DOWNLOAD PDF KCM 60Z7 Wheel Loader Shop Manual PN 93206-00300 by www.heydownloads.com

93206-00300 March 2015

SHOP MANUAL (Function & Structure) INTRODUCTION ....................................................................................................................................... IN-01~02 Symbol and Abbreviation........................................................................................................................... SY-1~2 SECTION 1

GENERAL

Group 1

Specifications ................................................................................................................................................. T1-1-1

Group 2

Component Layout...................................................................................................................................... T1-2-1

Group 3

Component Specifications ....................................................................................................................... T1-3-1

SECTION 2

SYSTEM

Group 1

Controller......................................................................................................................................................... T2-1-1

Group 2

Control System .............................................................................................................................................. T2-2-1

Group 3

ECM System .................................................................................................................................................... T2-3-1

Group 4

Hydraulic System .......................................................................................................................................... T2-4-1

Group 5

Electrical System ........................................................................................................................................... T2-5-1

SECTION 3

COMPONENT OPERATION

Group 1

Pump Device .................................................................................................................................................. T3-1-1

Group 2

Control Valve .................................................................................................................................................. T3-2-1

Group 3

Priority Valve................................................................................................................................................... T3-3-1

Group 4

Steering Valve ................................................................................................................................................ T3-4-1

Group 5

HST Motor ....................................................................................................................................................... T3-5-1

Group 6

Transmission................................................................................................................................................... T3-6-1

Group 7

Axle .................................................................................................................................................................... T3-7-1

Group 8

Brake Valve ...................................................................................................................................................... T3-8-1

Group 9

Others ............................................................................................................................................................... T3-9-1

Group 10

Ride Control Valve ......................................................................................................................................T3-10-1

Group 11

Pilot Valve ...................................................................................................................................................... T3-11-1

DIAGRAMS Electrical Connection Diagram Wiring Diagrams Hydraulic Circuit Diagram

All information, illustrations and specifications in this manual are based on the latest product information available at the time of publication. The right is reserved to make changes at any time without notice.

60Z7

INTRODUCTION To The Reader This manual is written for an experienced technician to provide technical information needed to maintain and repair this machine. y Be sure to thoroughly read this manual for correct product information and service procedures.

Additional References Please refer to the other materials (operation and maintenance manual, parts catalog, engine technical material, Kawasaki shop materials, etc.) in addition to this manual.

Manual Composition y Information included in the Workshop Manual: Technical information needed for maintenance and repair of the machine, tools and devices needed for maintenance and repair, maintenance standards, and removal / installation and assembly / disassembly procedures.

Our shop manuals consist of the Technical Manual, the Workshop Manual and the Engine Manual. y Information included in the Technical Manual: Technical information needed for machine pre-delivery and delivery, operation and activation of all devices and systems, operational performance tests, and troubleshooting procedures.

y Information included in the Engine Manual: Technical information needed for machine pre-delivery and delivery and maintenance and repair of the machine, operation and activation of all devices and systems, troubleshooting and assembly / disassembly procedures.

Page Number Each page has a number, located on the center lower part of the page, and each number contains the following information: Example: y Technical Manual: T 1-3-5 T 1 3 5

y Workshop Manual: W 1-3-2-5 W 1 3 2 5

Technical Manual Section Number Group Number Consecutive Page Number for Each Group

IN-01

Workshop Manual (disassembly and reassembly) Section Number Group Number Sub Group Number Consecutive Page Number for Each Group

INTRODUCTION Safety Alert Symbol and Headline Notations In this manual, the following safety alert symbol and signal words are used to alert the reader to the potential for personal injury of machine damage.

CAUTION: Indicated potentially hazardous situation which could, if not avoided, result in personal injury or death.

This is the safety alert symbol. When you see this symbol, be alert to the potential for personal injury. Never fail to follow the safety instructions prescribed along with the safety alert symbol. The safety alert symbol is also used to draw attention to component/part weights. To avoid injury and damage, be sure to use appropriate lifting techniques and equipment when lifting heavy parts.

IMPORTANT: Indicates a situation which, if not conformed to the instructions, could result in damage to the machine.

NOTE: Indicates supplementary technical information.

Units Used Example: 24.5 MPa (250 kgf/cm2, 3560 psi)

SI Units (International System of Units) are used in this manual. MKSA (Meter, Kilogram, Second, Ampere) system units and English units are also indicated in parentheses just behind SI units.

A table for conversion from SI units to other system units is shown below for reference purposes.

Quantity

To Convert From

Into

Multiply By

Length

0.03937

0.003281

US gal

0.2642

US qt

1.057

Volume

L 3

1.308

Weight

2.205

Force

kgf

0.10197

lbf

0.2248

N·m

kgf·m

Torque Pressure

0.10197 2

MPa

kgf/cm

MPa

psi

145.0

1.360

1.341

Temperature

°C

°F

°C×1.8+32

Velocity

km/h

mph

0.6214

-1

min

rpm

1.0

L/min

US gpm

0.2642

mL/rev

cc/rev

1.0

Power

Flow rate

NOTE: The numerical value in this manual might be different from the above-mentioned table.

IN-02

10.197

Symbol and Abbreviation Symbol and Abbreviation Symbol / Name Abbreviation T/M Transmission S/M Shop Manual

MC ECM ICF HST Controller

GSM

GPS CAN

A/C OPT MPDr. WU Li ATT

Explanation

Transmission Shop manual (Function and Structure, Operational Performance Test / Troubleshooting, Disassembly and Reassembly). Main Controller Main controller. MC controls the engine, pump, and valve according to the machine operating condition. Engine Control Module Engine controller. ECM controls fuel injection amount according to the machine operating condition. Information Controller Information Controller communicates with the Maintenance Pro Dr. (MPDr.) and GPS. Hydrostatic Transmission Controller Hydrostatic transmission controller. Hydraulic pump and motors drive the clutch where all power is transmitted by hydraulic fluid. HST controller controls the transmission, HST pump and HST motors according to the machine operating condition. Global System for Mobile communications Communication controller. GSM is a type of wireless controller communication system, is used in more than on 100 countries around Europe and Asia, and becomes the factual global standards of the mobile telephone. Global Positioning System Global positioning system. Controller Area Network CAN communication. CAN is a serial communications protocol internationally-standardized by ISO (International Organization for Standardization). Air Conditioner Air conditioner. Option Optional component. Maintenance Pro Dr. MPDr. is software that troubleshooting, monitoring, and adjustment. Warming-Up Warming-up. Low (Slow) Idle Slow idle engine speed. Attachment Attachment.

SY-1

Symbol and Abbreviation Symbol / Name Abbreviation DA Automatische Verstellung drehzahlabhängig (German) EGR Exhaust Gas Recirculation

Explanation Speed related automatic hydraulic control The EGR control re-circulates a part of exhaust gas in the intake manifold and combines it with intake-air. Therefore, combustion temperature is lowered and generation of oxide of nitrogen (NOx) is controlled.

SY-1

SECTION 1

GENERAL CONTENTS Group 1 Specifications Specifications ....................................................................... T1-1-1

Group 2 Component Layout Main Component (Overview) ......................................... T1-2-1 Main Component (Travel System) ................................ T1-2-2 Electrical System (Overview) .......................................... T1-2-3 Electrical System (Components Related with Relays) ......................... T1-2-4 Electrical System (Components Related with Engine)........................ T1-2-4 Electrical System (Cab) ...................................................... T1-2-5 Front Console.................................................................. T1-2-6 Right Console.................................................................. T1-2-7 Rear Console ................................................................... T1-2-8 Monitor Panel ................................................................. T1-2-9 Engine ...................................................................................T1-2-10 Pump Device ......................................................................T1-2-11 Transmission/HST Motor ...............................................T1-2-12 Control Valve.......................................................................T1-2-13 Priority Valve .......................................................................T1-2-14 Ride Control Valve (Option) ...........................................T1-2-15 Secondary Steering Block (Option) ............................T1-2-16 Secondary Steering Pump (Option) ...........................T1-2-16 Pilot Shut-Off Solenoid Valve (Hydraulic Operated Type: Option) .......................T1-2-17

Group 3 Component Specifications Engine ..................................................................................... T1-3-1 Engine Performance Curve (TCD3.6 L4) ................ T1-3-4 Engine Accessories ............................................................. T1-3-5 Hydraulic Component ....................................................... T1-3-7 Electrical Component ......................................................T1-3-12

60Z7 F&S (US)

(Blank)

60Z7 F&S (US)

SECTION 1 GENERAL Group 1 Specifications Specifications

45 ° I G E

H 50 °

40 °

F D R1

R2 MNCB-12-001

Model Bucket Capacity: heaped Operating Weight Tipping Load (Straight) Engine A: Overall Length B: Overall Width (Bucket) C: Overall Height D: Wheel Base E: Tread F: Ground Clearance G: Bucket Hinge Height H: Dumping Clearance (45 °) I: Dumping Reach (45 °) R1: Minimum Rotation Radius R2: Minimum Rotation Radius Travel Speed Forward/Reverse Transmission Speeds (F/R) Articulation Angle (Left/Right) deg Tire Size

m3 (Y3) kg (lb) kg (lb)

60Z7 *1.5 (1.96) 8120 (1790) 5310 (11707) DEUTZ TCD 36 6420 (253) 2450 (96.5) 3210 (126.4) 2725 (107.3) 1820 (71.7) 370 (14.6) 3560 (140.2) 2705 (106.5) 1010 (39.8) 4690 (184.6) 5430 (213.8) 34.5 (21.4)/34.5 (21.4) 2/2 40 17.5-25-12PR

mm (in) mm (in) mm (in) mm (in) mm (in) mm (in) mm (in) mm (in) mm (in) mm (in) mm (in) km/h (mph) (°) -

NOTE: x * BOC (Bolt-On Cutting Edge) x These specifications are subject to change without notice.

T1-1-1

SECTION 1 GENERAL Group 1 Specifications (Blank)

T1-1-2

SECTION 1 GENERAL Group 2 Component Layout Main Component (Overview)

3 2

8 9

25 10 11 12

23 22

13 14

15 20

16 TNCC-01-02-001

1234567-

Bucket Bell Crank (Lever) Bucket Cylinder Lift Arm Steering Valve Control Lever Brake Valve

891011121314-

Priority Valve Hydraulic Oil Tank Brake Oil Reserve Tank Muffler Coolant Reservoir Oil Cooler Radiator

15161718192021-

T1-2-1

Intercooler Fuel Tank Engine Fuel Pre-Filter Fuel Main Filter Air Cleaner Pump Device

22232425-

Declutch Valve Control Valve Lift Arm Cylinder Bucket Link

SECTION 1 GENERAL Group 2 Component Layout Main Component (Travel System)

5 6 7

8 TNCC-01-02-002

123-

Front Axle Steering Cylinder HST Filter

456-

Brake/Transmission Oil Filter Transmission Propeller Shaft (Rear)

789-

T1-2-2

Rear Axle HST Motor Propeller Shaft (Front)

SECTION 1 GENERAL Group 2 Component Layout Electrical System (Overview)

7 8 9 10 11

15 14

TNCC-01-02-003

12345-

Bucket Proximity Switch Front Work Light Horn Front Wiper Motor (Cab) Pressure Sensor (Front Attachment Pressure)

67891011-

Rear Wiper Motor (Cab) HST Oil Temperature Sensor Battery Relay Reverse Buzzer Rear Work Light Battery

12- Rear Combination Light (Turn Signal Light, Tail Light, Brake Light, Backup Light) 14- Fuel Level Sensor 15- Brake Oil Level Switch 16- Brake Light Switch

T1-2-3

17- Clearance light/Turn Signal light 18- Head Light

SECTION 1 GENERAL Group 2 Component Layout Electrical System (Components Related with Relays) 2

5 TNCC-01-02-004

Front Side of Machine

12-

Fusible Link B (65A) Fusible Link A (65A)

34-

Fusible Link (100A) (2 Used) Battery Relay

Preheat Relay 2

Electrical System (Components Related with Engine) 7

TNCC-01-02-011

9 a-

Front Side of Machine

ECM

Fuel Pressure Switch (Fuel Main Filter)

T1-2-4

Electric fuel pump

Water Separator Switch (Fuel Pre-Filter)

SECTION 1 GENERAL Group 2 Component Layout Electrical System (Cab) Detail D

a 4

TNDB-01-02-032 Detail E

E 12 7

TNDB-01-02-029

15 13

TNCC-05-02-012

Front Console (Refer to T1-2-6.)

Right Console (Refer to T1-2-7.)

Rear Console (Refer to T1-2-8.)

1234-

Radio Upper Switch Panel (Option) Speaker Rear Wiper Motor

5789-

Accelerator Pedal Sensor Brake Light Switch Front Wiper Motor Air Conditioner Controller

10111213-

Front Wiper (1) Relay (WR1) Front Wiper (2) Relay (WR2) GSM (OPT)/GPS (OPT) Flasher Relay

T1-2-5

15- MC (Main Controller)

SECTION 1 GENERAL Group 2 Component Layout Front Console 1

2 3

MNDB-01-001

15 16 17 12 18

19 20

22 14

123456-

MNDB-01-002

Air Conditioner Vent Hazard Light Switch Work Light Switch Parking Brake Switch Neutral Lever Lock (For Forward/Reverse Lever) Steering Wheel

78910-

Monitor Panel Wheel Horn Switch Accelerator Pedal Brake/Inching Pedal (Both at left and right are interlocked.) 11- Front/Rear Wiper Switch

21 MNDB-01-003

12- Forward/Reverse Lever/Shift Switch 13- Steering Column Tilt Pedal 14- Tilt/Telescopic Lever 15- Turn Signal Lever/Light Switch/Dimmer Switch 16- Key Switch

T1-2-6

171819202122-

Slow Speed (L) Select Switch Auxiliary Auxiliary Auxiliary Ashtray Cigar Lighter

SECTION 1 GENERAL Group 2 Component Layout Right Console y Manual Type (Standard) 1

11 4

12-

Control Lever Auxiliary Control Lever Lock (Option)

345-

Auxiliary Control Lever (Option) Ride Control Switch (Option) Power Mode Switch

678-

MNCB-01-005

Back Buzzer Switch (Option) Secondary Steering Operation Check Switch (Option) Auxiliary

9- Traction Control Switch 10- Control Lever Lock 11- Quick Shift Switch (QSS)

y Hydraulic Pilot Type (Option) 2

4 5

7 8

9 10

15 17

12345-

Joystick Type Lever Auxiliary Control Lever (Option) Control Lever Lock Switch Auxiliary Traction Control Switch

678910-

14 13

12 MNCB-01-006

Power Mode Switch Auxiliary Auxiliary Back Buzzer Switch (Option) Auxiliary

11- Secondary Steering Operation Check Switch (Option) 12- Auxiliary 13- Auxiliary 14- Auxiliary 15- Ride Control Switch (Option)

T1-2-7

16171819-

Armrest Adjust Handle Armrest Quick Shift Switch (QSS) Horn Switch

SECTION 1 GENERAL Group 2 Component Layout Rear Console

12 11 10 9

17 16 15 14 13

22 21 20 19 18

27 26 25 24 23

12345678-

Fuse Box B Fuse Box A MPDr. Connector Preheat Relay 1 Back Buzzer Relay A/C Condenser Relay (CR1) A/C Condenser (High Pressure) Relay (CR2) Fuel Pump Relay (A-R1)

9101112-

Head Light Relay (A-R2) High-Beam Relay (A-R3) Bucket Leveler Relay (A-R4) Alternator Indicator Relay 1 (A-R5) 13- Work Light (Front) Relay (A-R6) 14- Work Light (Rear) Relay (A-R7) 15- Right Turn Signal Light Relay (A-R8)

16- Horn Relay (A-R9) 17- Alternator Indicator Relay 2 (A-R10) 18- Parking Brake Relay 1 (B-R1) 19- Parking Brake Relay 2 (B-R2) 20- Control Lever Lock Relay (B-R3) (Option) 21- Brake Light Relay (B-R4) 22- Load Dump Relay (B-R5)

T1-2-8

TNED-01-02-009

23- Neutral Relay (B-R6) 24- Left Turn Signal Light Relay (B-R7) 25- Front Washer Relay (B-R8) 26- Rear Wiper Relay (B-R9) 27- Rear Washer Relay (B-R10) 28- Relay Box A 29- Relay Box B

SECTION 1 GENERAL Group 2 Component Layout Monitor Panel

7 8

9 10

37 12 36 35

14 15

33 16

32 31 30

1234-

Left Turn Signal Light Indicator High-Beam Indicator Work Light Indicator Right Turn Signal Light Indicator 5- (Unused) 6- (Unused) 7- Service Indicator 8- Maintenance Indicator 9- Parking Brake Indicator 10- Clearance Light Indicator 11- Control Lever Lock Indicator (Option)

12131415161718192021-

29 28 27 26

25 24 23 22 21 20 19 18 17

(Unused) (Unused) Brake Oil Low Level Indicator Secondary Steering Indicator (Option) Low Steering Oil Pressure Indicator (Option) Seat Belt Indicator (Option) Alternator Indicator Fuel Gauge Power Mode Indicator Monitor Display Selection Switch

22- (Unused) 23- Monitor Display Selection Switch (Up) 24- Preheat Indicator 25- Monitor Display Selection Switch (Down) 26- (Unused) 27- Monitor Display 28- (Unused) 29- Engine Warning Indicator 30- Overheat Indicator 31- Coolant Temperature Gauge

T1-2-9

MNDB-01-034

32- Engine Oil Low Pressure Indicator 33- (Unused) 34- (Unused) 35- (Unused) 36- (Unused) 37- (Unused) 38- HST Warning Indicator 39- HST Oil Temperature Indicator 40- HST Oil Temperature Gauge

SECTION 1 GENERAL Group 2 Component Layout Engine

1 2 8 7 3

6 5 4

13 11

10 TNCC-01-02-010

1234-

Common Rail Pressure Sensor Alternator Fan Belt Auto Tension Pulley

567-

Engine Oil Filter Starter Coolant Temperature Sensor

Boost Pressure/Boost Temperature Sensor 9- Engine Oil Pressure Sensor 10- Cam Angle Sensor

T1-2-10

11- Crank Speed Sensor 12- EGR Valve 13- Supply Pump

SECTION 1 GENERAL Group 2 Component Layout Pump Device

1 a A

10 9

7 T4FJ-01-02-012

View A

T4FJ-01-02-012

Engine Side

Forward/Reverse Control Solenoid Valve Cutoff Valve HST Pump

23-

5678-

Main Pump Brake/Transmission Pump Low-Pressure Relief Valve DA Valve

High-Pressure Relief Valve (Forward Circuit Side) 10- Displacement Angle Control Cylinder

T1-2-11

11- High-Pressure Relief Valve (Reverse Circuit Side)

SECTION 1 GENERAL Group 2 Component Layout Transmission/HST Motor

9 6

a T4FJ-01-02-014

Front Side of Machine

123-

Transmission Vehicle Speed Sensor Driving Mode Selection Valve

456-

Driving Mode Selection Solenoid Valve HST Motor HST Circuit Pressure Sensor

789-

T1-2-12

Displacement Angle Control Solenoid Valve Driving Control Solenoid Valve Parking Brake Solenoid Valve

10- Parking Brake 11- Pressure Sensor (Parking Brake)

SECTION 1 GENERAL Group 2 Component Layout Control Valve y Manually Operated Type (Standard)

2 T4FJ-01-02-015

Front Side of Machine

Main Relief Valve

Overload Relief Valve (Bucket: Rod Side)

y Hydraulic Operated Type (Option)

5 1

Front Side of Machine

12-

Main Relief Valve Overload Relief Valve (Bucket: Rod Side)

Make-Up Valve (Lift Arm: Rod Side)

T1-2-13

Overload Relief Valve (Lift Arm: Bottom Side)

TNCC-03-02-001

Overload Relief Valve (Bucket: Bottom Side)

SECTION 1 GENERAL Group 2 Component Layout Priority Valve

a a-

Front Side of Machine

Pressure Sensor (Front Attachment Pressure)

T1-2-14

T4FJ-01-02-016

SECTION 1 GENERAL Group 2 Component Layout Ride Control Valve (Option)

3 TNCC-01-02-014

12-

Overload Relief Valve Ride Control Solenoid Valve

Ride Control Accumulator

T1-2-15

SECTION 1 GENERAL Group 2 Component Layout Secondary Steering Block (Option)

TNCC-01-02-015

Secondary Steering Pump (Option) 5

TNED-01-02-019

12-

Secondary Steering Block Check Valve

34-

Steering Pressure Switch Secondary Steering Pump

56-

T1-2-16

Relief Valve Gear Pump

Electric Motor

SECTION 1 GENERAL Group 2 Component Layout Pilot Shut-Off Solenoid Valve (Hydraulic Operated Type: Option)

1 3 4

TNCC-01-02-013

Pilot Shut-Off Solenoid Valve

Pressure Sensor (Primary Pilot Pressure)

34-

T1-2-17

Pilot Accumulator Check Valve

SECTION 1 GENERAL Group 2 Component Layout (Blank)

T1-2-18

SECTION 1 GENERAL Group 3 Component Specifications Engine Manufacturer

DEUTZ corp.

Model

TCD3.6 L4

Type

Diesel, 4-Cycle, Water-cooled, Direct Injection Type, Exhaust Turbo Charged Type

Cyl. No.- Bore × Stroke

4-98 mm × 120 mm (3.9 in × 4.7 in)

Piston Displacement

3621 cm3 (221 in3)

Rated Output

74 kW/2000 min-1 (101 PS/2000 rpm)

Compression Ratio

17.2

Dry Weight

365 kg (805 lb)

Firing Order

1-3-4-2

Rotation Direction

Clockwise (Viewed from fan side)

T1-3-1

SECTION 1 GENERAL Group 3 Component Specifications Engine COOLING SYSTEM

Cooling Fan

Dia. 510 mm (20 in), 7 Blades, Hybrid

Thermostat

Cracking Temperature at Atmospheric Pressure : 88 °C (190 °F) Full Open 95 °C (203 °F)

LUBRICATION SYSTEM

STARTING SYSTEM

Lubrication Pump Type

Trochoid Pump

Oil Filter

Full-Flow Paper Element Type

Oil Cooler

Water Cooled Integral Type

Motor

Magnetic Pinion Shift Reduction Type

Voltage/Output

24 V/4.0 kW

PREHEAT SYSTEM

Preheating Method

Glow Plug Type

ENGINE STOP SYSTEM

Stop Method

Fuel Shut-Off (Electronic Control)

ALTERNATOR

Type

AC Type

Voltage/Output

24 V/80 A

SUPERCHARGING SYSTEM

Type

Exhaust-Turbocharger Type, Forced Lubrication

FUEL SYSTEM

Type

Common Rail Type

Governor

Electronic All Speed Control

Injection Nozzle

Electrical Multi-Hole Injector

T1-3-2

SECTION 1 GENERAL Group 3 Component Specifications IMPORTANT: This list shows design specifications, which are not servicing standards. PERFORMANCE

Fuel Consumption Ratio

225 g/kW/h (165 g/PS·h) (at Full Load : 2000 min-1)

Maximum Output Torque

410 N·m (41 kgf·m, 302 lbf·ft) at1600 min-1

No Load Speed

Slow : 880±50 min-1 Fast : 2200±50 min-1

T1-3-3

SECTION 1 GENERAL Group 3 Component Specifications Engine Performance Curve (TCD3.6 L4) Test Condition: 1. In conformity with JIS D1005 (Performance Test Method for Diesel Engine Used for Construction Machinery) under standard atmospheric pressure. 2. Equipped with alternator.

N·m

min-1 (rpm)

kW : Output N·m : Torque

min-1 (rpm) : Engine Speed

T1-3-4

TNCC-01-03-001

SECTION 1 GENERAL Group 3 Component Specifications Engine Accessories RADIATOR ASSEMBLY

Type

Radiator, Oil Cooler, Intercooler Parallel Type Assembly.

Weight

16.2 kg (36 lb)

Radiator

Inter Cooler 2

Air-Tight Test Pressure

100 kPa (1.0 kgf/cm , 14 psi)

245 kPa (2.5 kgf/cm2, 35.5 psi)

Cap Opening Pressure

90 kPa (0.9 kgf/cm2, 13 psi))

−

Oil Cooler Air-Tight Test Pressure

1500 kPa (15 kgf/cm2, 218 psi)

Cap Opening Pressure

−

T1-3-5

SECTION 1 GENERAL Group 3 Component Specifications BATTERY

Type

75D26R

Voltage

12 V

Capacity

58 Ah (5-Hour Rate)

Weight

Approx. 16 kg (35 lb) ×2

T1-3-6

SECTION 1 GENERAL Group 3 Component Specifications Hydraulic Component HST PUMP

Type Maximum Flow Rate (Theoretical Value ) Theoretical Displacement High-Pressure Relief Valve Set-Pressure Low-Pressure Relief Valve Set-Pressure Cutoff Valve Set-Pressure

HST CHARGING PUMP

PUMP DEVICE

Control System Type Rated Current (Theoretical Value ) Theoretical Displacement Type Speed Ratio Function (At the HST Pump Side) Rated Current (Theoretical Value ) Theoretical Displacement

HST MOTOR

Type Maximum Flow Rate Control System

Swash Plate Type (Two-Direction Displacement Angle) Variable Displacement Plunger Pump 0 to 156 L (41 gal)/min-1 at 2000 min-1 71 cm3 (4.3 in3)/rev 43.2±1.0 MPa (440±10 kgf/cm2, 6264 psi), Differential Pressure 41.2 MPa (420 kgf/cm2, 5974 psi) 2.5±0.1 MPa (25±1 kgf/cm2, 363 psi) 40.2±1.0 MPa (410±10 kgf/cm2, 5829 psi), Differential Pressure 38.2 MPa (390 kgf/cm2, 5539 psi) Direct-Drive-Type Speed Sensitive Output Control Internal Gear Pump 39.2 L (10.4 gal)/min-1 at 2000 min-1 19.6 cm3 (1.2 in3)/rev Fixed Displacement Type Gear Pump Main Pump: 1, Brake/Transmission Pump: 1 Main Pump, Brake/Transmission Pump Main Pump: 121 L (32 gal)/min-1at 2000 min-1 Brake/Transmission Pump 22 L (5.8 gal)/min-1at 2000 min-1 Main Pump: 60.8 cm3 (3.7 in3)/rev Brake Transmission Pump: 1 cm3/rev Bent-Axis Type Variable Displacement Axial Plunger Motor 16 to107 cm3 (1 to 6.5 in3)/rev Proportional Solenoid Control

T1-3-7

SECTION 1 GENERAL Group 3 Component Specifications Hydraulic Component PRIORITY VALVE CONTROL VALVE (Mechanical Type)

Relief Set-Pressure Type Main Relief Set-Pressure Overload Relief Set-Pressure CONTROL VALVE Type (Hydraulic Type) (Option) Main Relief Set-Pressure Overload Relief Set-Pressure

FRONT ATTACHMENT PILOT VALVE (Mono Lever) (Option) AUXILIARY PILOT VALVE (Option) PILOT SHUT-OFF SOLENOID VALVE (Option) PILOT ACCUMULATOR (Option)

Type Plunger Stroke

17.2 MPa (2494 psi) at 61 L (16 gal)/min Manually Operated Type (2-Spools) 20.6 MPa (2988 psi) at 140 L (37 gal)/min Bucket Rollback: 16.2 MPa (2349 psi) at 25 L (6.6 gal)/min Hydraulic Operated Type (2-Spools) 20.6 MPa (2988 psi) at 110 L (29 gal)/min Lift Arm Raise: 27.9 MPa (4046 psi) at 50 L (13 gal)/min Bucket Rollback: 23.5 MPa (3408 psi) at 50 L (13 gal)/min Bucket Dump: 23.5 MPa ( 3408 psi) at 50 L (13 gal)/min Joystick Lever, 4-Port (With Electromagnetic Detent) 1, 2, 3, 4 Port: 10 mm (0.4 in)

Type Plunger Stroke Type Rated Voltage Coil Resistance Capacity Charging Pressure

Finger Type, 2-Port (Without Detent) 1, 2 Port: 4.8 mm (0.19 in) ON/OFF Solenoid Valve DC 24 V 49 Ω at 20 °C (68 °F) 0.75 L (0.2 gal) 2.0 MPa (290 psi) at 20 °C (68 °F)

T1-3-8

SECTION 1 GENERAL Group 3 Component Specifications Hydraulic Component STEERING VALVE

BRAKE VALVE TRANSMISSION

AXLE (Front, Rear)

PROPELLER SHAFT

Type Overload Relief Set-Pressure Gerotor Capacity Brake Pressure Type Speed Ratio Clutch Pressure Parking Brake Release Pressure Model Brake Type Brake Pressure Final Reduction Gear Ratio Type Dimension between Pins

Orbitrol® Type 17.2 MPa (175 kgf/cm2, 2494 psi) at 1 L (1 quart)/min 438 cm3 (26.7 in3)/rev 1.5 MPa (15 kgf/cm2, 218 psi) Counter Shaft Type Low Speed: 3.407 Fast Speed: 1.088 1.6 to 1.8 MPa (16 to 18 kgf/cm2, 232 to 261 psi) 1.5 MPa (15 kgf/cm2, 218 psi) Two Stage Reduction Wet-Type Single Disk Brake 1.5 MPa (15 kgf/cm2, 218 psi) 20.152 Cruciform Joint Type Front : 1410 mm (4’7.5”) Rear : 111 mm (4.4”)

NOTE: Orbitrol® is a trademark of Eaton Corporation.

T1-3-9

SECTION 1 GENERAL Group 3 Component Specifications Hydraulic Component RIDE CONTROL VALVE (Option)

Type

Hydraulic Operated Type

Overload Relief Set-Pressure

28.4 MPa (290 kgf/cm2, 4119 psi) at 50 L (13 gal)/min

Charge-Cut Valve

8.5 MPa (87 kgf/cm2, 1233 psi)

RIDE CONTROL ACCUMULATOR (Option)

Capacity

2.5 L (0.66 gal)

Charging Pressure

2.2 MPa (22 kgf/cm2, 319 psi)

SECONDARY STEERING BLOCK (Option)

Function Rated Pressure

Secondary Steering Circuit (OPT) 29.4 MPa (300 kgf/cm2, 4263 psi)

T1-3-10

SECTION 1 GENERAL Group 3 Component Specifications Hydraulic Component CYLINDER

FILTER

Lift Arm (Right, Left)

Bucket

Steering

Rod Diameter

60 mm (2.4”)

65 mm (2.6”)

35 mm (1.4”)

Cylinder Bore

105 mm (4.1”)

125 mm (4.9”)

60 mm (2.4”)

Stroke

710 mm (28”)

445 mm (18”)

395 mm (16”)

Fully Retracted Length

1185 mm (3’11”)

990 mm (39”)

675 mm (27”)

Plating Thickness

30 μm (1.18 μm)

Full-Flow Filter (Filtration)

β10≥1.2 (filters 16% or more particles 10 μm in diameter)

Suction Filter (Filtration)

177 μm (80 mesh)

Filter (HST, Brake/Transmission)

β10≥1.4 (filters 30% or more particles 10 μm in diameter)

T1-3-11

SECTION 1 GENERAL Group 3 Component Specifications Electrical Component ENGINE OIL PRESSURE SENSOR

Operating Pressure

48 kPa (0.5 kgf/cm2, 7.0 psi)

COOLANT TEMPERATURE Operating Temperature SENSOR

-10 to 110 °C (14 to 230 °F)

FUEL LEVEL SENSOR

Resistance Value

Empty : 90 +10/0 Ω, Full : 10 0/-4 Ω

HYDRAULIC OIL TEMPERATURE SENSOR

Operating Temperature

-30 to 120 °C (-22 to 248 °F)

BATTERY RELAY

Voltage/Current

24 V/100 A

PREHEAT RELAY 2

Voltage/Current

24 V/100 A

T1-3-12

SECTION 1 GENERAL Group 3 Component Specifications Electrical Component AIR FILTER RESTRICTION SWITCH

Operating Pressure

6.2±0.6 kPa (0.9±0.09 psi)

HORN

Voltage/Current

24 V / 1.5±0.7 A

Sound Pressure

113±5 dB (A) at 2 m (6’7”)

Work Light

Halogen 24 V, 70 W (51.6 PS)

Cab Light

24 V, 10 W (7.4 PS)

Head Light

24 V, 62/62 W (45.7 PS)

Turn Signal Light

24 V, 25 W (18.4 PS) (Front), 21 W (15.5 PS) (Rear)

Clearance Light

24 V, 5 W (3.7 PS)

ILLUMINATION

AIR CONDITIONER

SECONDARY STEERING PUMP UNIT (Option)

License Light

24 V, 12 W (8.9 PS)

Tail Light

24 V, 5 W (3.7 PS)

Brake Light

24 V, 21 W (15.5 PS)

Refrigerant

134 a

Cooling Ability

4.5 kW or More

Cool Air Volume

550 m3/h (719 yd3/h) or More

Heating Ability

5.81 kW (7.8 HP) or More

Warm Air Volume

390 m3 (510 yd3)/h or More

Temperature Adjusting System

Electronic Type

Refrigerant Quantity

800±50 g (1.76±0.1 lb)

Compressor Oil Quantity

160 cm3 (9.8 in3)

Type

Electric Motor Operated Type

Theoretical Displacement

7.0 cm3 (0.4 in3)/rev

Relief Set-Pressure

10.0 MPa (102 kgf/cm2, 1450 psi) at 11.3 L (gal)/min

Electric Motor

24 V, 2.4 kW (3.2 HP)

T1-3-13

SECTION 1 GENERAL Group 3 Component Specifications (Blank)

T1-3-14

SECTION 2

SYSTEM CONTENTS Group 1 Controller Outline .................................................................................... T2-1-1 CAN Circuit ............................................................................ T2-1-2

Group 2 Control System Outline .................................................................................... T2-2-1 Engine Control ..................................................................... T2-2-3 Engine Control System Layout ................................. T2-2-3 Accelerator Pedal Control........................................... T2-2-4 HST Pump Control .............................................................. T2-2-6 HST Pump Control System Layout .......................... T2-2-7 Forward/Reverse Lever Control................................ T2-2-8 HST Brake .............................................................................T2-2-14 Traveling .........................................................................T2-2-14 Stopping .........................................................................T2-2-16 Inching Operation .......................................................T2-2-18 HST Motor Control ............................................................T2-2-20 Driving Slow Speed Selection Control.................T2-2-22 Traction Force Limit Control ....................................T2-2-24 Traction Control ...........................................................T2-2-26 Overrun Limit Control ................................................T2-2-28 Engine Protection Control........................................T2-2-30 Overheat Prevention Control ..................................T2-2-32 Driving Slow Speed Switching Shock Reduction Control ......................................................T2-2-34 Transmission Control .......................................................T2-2-38 Transmission Control System Layout ...................T2-2-38 Driving Slow Speed Selection Control.................T2-2-40 Other Controls ...................................................................T2-2-44 Backup Light Lighting Control ...............................T2-2-46 Ride Control Function (Option) ..............................T2-2-48 Parking Brake Operation Indicator Control........T2-2-50 Secondary Steering Control (Option) ..................T2-2-52 Bucket Auto Leveler Control....................................T2-2-56 Lift Arm Float Control (Hydraulic Pilot Type) (Option) .........................................................................T2-2-60 Lift Arm Kickout Control (Hydraulic Pilot Type) (Option) .........................................................................T2-2-62

Group 3 ECM System Outline .................................................................................... T2-3-1 Fuel Injection Control ........................................................ T2-3-2 Fuel Injection Amount Control ................................. T2-3-4 Fuel Injection Pressure Control ................................ T2-3-6 Fuel Injection Timing Control.................................... T2-3-8 Fuel Injection Rate Control ........................................ T2-3-8 EGR Control .........................................................................T2-3-10 Neutral Engine Start Control.........................................T2-3-12 Engine Trouble Alarm Control ......................................T2-3-14 Engine Oil Pressure Alarm Control..............................T2-3-16 Overheat Alarm Control .................................................T2-3-17

Group 4 Hydraulic System Outline .................................................................................... T2-4-1 Main Circuit ........................................................................... T2-4-2 Steering Circuit............................................................... T2-4-4 Priority Valve Circuit (Neutral) ................................... T2-4-6 Steering Circuit (Right Turn) ...................................... T2-4-8 Steering Stop Circuit ..................................................T2-4-10 Secondary Steering Circuit (OPT) ...............................T2-4-12 Lift Arm, Bucket Circuit ...................................................T2-4-14 Neutral Circuit...............................................................T2-4-14 Single Operation Circuit............................................T2-4-14 Relief Circuit ..................................................................T2-4-14 Single Operation Circuit............................................T2-4-16 Combined Operation Circuit ...................................T2-4-18 HST Circuit ...........................................................................T2-4-22 Charge Circuit ...............................................................T2-4-24 Neutral Circuit...............................................................T2-4-24 Forward Circuit .............................................................T2-4-26 Reverse Circuit ..............................................................T2-4-28 Inching Circuit ..............................................................T2-4-30 Transmission Circuit .........................................................T2-4-33 Outline of Clutch Circuit ...........................................T2-4-33 Travel Slow Mode Selector Circuit .........................T2-4-34 Travel Fast Mode Selector Circuit...........................T2-4-34 Transmission Lubrication Circuit............................T2-4-34 Outline of Brake Circuit .............................................T2-4-37 Service Brake Circuit ...................................................T2-4-38 Parking Brake Circuit ..................................................T2-4-40 Ride Control Circuit (Option) ........................................T2-4-42 Pilot Circuit (Only Hydraulic Operated Type) (Option) ..........................................................................T2-4-44

60Z7 F&S (US)

Group 5 Electrical System Outline .................................................................................... T2-5-1 Main Circuit ........................................................................... T2-5-2 Electric Power Circuit (Key Switch: OFF) ................ T2-5-4 CAN Circuit....................................................................... T2-5-6 Accessory Circuit (Key Switch: ACC) ....................... T2-5-8 Light Bulb Check Circuit (Key Switch: ON)..........T2-5-10 Preheating Circuit (Key Switch: ON)......................T2-5-12 Engine Starting Circuit (Key Switch: START) ......T2-5-14 Charging Circuit (Key Switch: ON) .........................T2-5-16 Alternator Operation...............................................T2-5-18 Regulator Operation ...............................................T2-5-18 Surge Voltage Prevention Circuit ...........................T2-5-20 Engine Stop Circuit .....................................................T2-5-22 Pilot Shut-Off Circuit (Key Switch: ON) (Hydraulic Operated Type)(Option) ....................T2-5-24 Accessory Circuit ...............................................................T2-5-29 Wiper/Washer Circuit .................................................T2-5-30 Front Wiper Circuit (INT) ........................................T2-5-30 Front Wiper Circuit (Slow)......................................T2-5-32 Front Wiper Circuit (Fast) .......................................T2-5-34 Front Washer Circuit ................................................T2-5-36 Rear Washer Circuit ..................................................T2-5-38 Rear Wiper Circuit .....................................................T2-5-40 Rear Wiper, Washer Circuit ....................................T2-5-42 Cab Light Circuit ..........................................................T2-5-44 Front Cab Light Circuit............................................T2-5-44 Rear Cab Light Circuit .............................................T2-5-44 Light/Horn Circuit .............................................................T2-5-47 Light Circuit ...................................................................T2-5-48 S Position .....................................................................T2-5-48 H Position ....................................................................T2-5-50 High-Beam Circuit ....................................................T2-5-52 Work Light Circuit ........................................................T2-5-54 Turn Signal Light Circuit............................................T2-5-58 Brake Light Circuit .......................................................T2-5-62 Hazard Light Circuit ....................................................T2-5-64 Horn Circuit ...................................................................T2-5-66 Parking Brake Circuit ..................................................T2-5-68

60Z7 F&S (US)

SECTION 2 SYSTEM Group 1 Controller Outline The following controllers are provided in this machine in order to control functions. Each controller excluding the communication controller communicates by using the CAN circuit and sends or receives the required signal. Controller

Control

Controls the engine speed, HST pump, valves, HST motor, and transmission. Controls the engine. Accumulates the operating information and alarms. Controls the wiper and buzzer. Displays the gauge and indicator. Controls the air conditioner. Sends the mails and operating information.

ECM ICF Monitor Controller Air Conditioner Controller Communication Controller

NOTE: Refer to the corresponding group for details of each controller control.

T2-1-1

Comment on Control T2-2 T2-3 T5-3 T5-2 T5-8 T5-3

SECTION 2 SYSTEM Group 1 Controller CAN Circuit CAN (Controller Area Network) is ISO Standards of the serial communication protocol. The network (CAN bus (4)), CAN 1 (1) is equipped for this machine. CAN bus (4) consists of two harnesses, CAN-H (High) (2) and CAN-L (Low) (3). Each controller judges the CAN bus (4) level due to potential difference between CAN-H (High) (2) and CAN-L (Low) (3). Each controller arranges the CAN bus (4) level and sends the signal and data to other controllers. In addition, termination resistors (120 Ω) (17) are installed to both ends of CAN bus (4).

T2-1-2

SECTION 2 SYSTEM Group 1 Controller

2 1

4 3

TDEK-02-03-004

TNCB-02-05-001

1234-

CAN 1 CAN-H (High) CAN-L (Low) CAN Bus

791011-

ECM (Engine Controller) MC (Main Controller) Communication Controller ICF (Information Controller)

12131417-

T2-1-3

MPDr. Air Conditioner Controller Monitor Controller Termination Resistor (120 Ω)

SECTION 2 SYSTEM Group 1 Controller (Blank)

T2-1-4

SECTION 2 SYSTEM Group 2 Control System Outline MC is used in order to control the machine operations. The signals from the accelerator pedal sensor, various sensors, and switches are sent to MC and processed in the logic circuit. MC sends the signals equivalent to the target engine speed to ECM by using CAN communication in order to control the engine. (Refer to SYSTEM / ECM System.) In addition, MC activates the forward/reverse control solenoid valve, travel control solenoid valve, displacement angle control solenoid valve, and travel mode selector solenoid valve in order to control HST pump, HST motor, and the transmission.

NOTE: HST: Hydro Static Transmission

T2-2-1

SECTION 2 SYSTEM Group 2 Control System

Input Signal Accelerator Pedal Sensor

Forward/Reverse Lever

Shift Switch Slow Speed (L) Select Switch Power Mode Switch Quick Shift Switch Traction Control Switch Ride Control Switch (Option) Machine Speed Sensor HST Pressure Sensor Pressure Sensor (Front Attachment Pressure)

Coolant Temperature Sensor Crank Speed Sensor Cam Angle Sensor

Output Signal Engine Control (ECM) Accelerator Pedal Control

HST Pump Control (Forward/Reverse Control Solenoid Valve) Forward/Reverse Lever Control

J J J J J J J J J

J J J

ECM

J J

Transmission Control (Travel Mode Selector Solenoid Valve) Driving Slow Mode Selection Control Other Controls

CAN

Parking Brake Pressure Sensor HST Oil Temperature Sensor Secondary Check Switch (Option)

HST Motor Control (Travel Control Solenoid Valve, Displacement Angle Control Solenoid Valve) Driving Slow Speed Selection Control Traction Force Limit Control Traction Control Overrun Limit Control Engine Protection Control Overheat Prevention Control Driving Slow Speed Switching Shock Reduction Control

Backup Light Lighting Control Ride Control Function (Option) Parking Brake Operation Indicator Control Secondary Steering Control (Option) Bucket Auto Leveler Control Lift Arm Float Control (Hydraulic Pilot Type) (Option) Lift Arm Kickout Control (Hydraulic Pilot Type) (Option)

Monitor Controller

T2-2-2

SECTION 2 SYSTEM Group 2 Control System Engine Control The engine control consists of the followings. x Accelerator Pedal Control

Engine Control System Layout

T4FJ-02-02-001

123-

Accelerator Pedal Sensor Accelerator Pedal MC

456-

CAN Communication ICF ECM

T2-2-3

Engine

SECTION 2 SYSTEM Group 2 Control System Accelerator Pedal Control Purpose: The accelerator pedal control controls the engine speed according to the depressing amount of accelerator pedal (2).

Operation: 1. MC (3) receives the signal from accelerator pedal sensor (1). The signal changes according to the depressing amount of accelerator pedal (2). 2. MC (3) sends the signals equivalent to the target engine speed to ECM (6) by using CAN communication (4) according to the depressing amount of accelerator pedal (1).

B C

3. ECM (6) controls the engine speed according to CAN communication (4).

AB-

4. When accelerator pedal sensor (1) becomes abnormal, MC (3) sends the signals to hold engine speed at 1300 min-1 to ECM (6) by using CAN communication (4) and fix the engine speed.

T2-2-4

Engine Speed Depressing Amount of Accelerator Pedal

D CD-

Low Idle Position High Idle Position

SECTION 2 SYSTEM Group 2 Control System 2

T4FJ-02-02-002

123-

Accelerator Pedal Sensor Accelerator Pedal MC

456-

CAN ICF ECM

78-

T2-2-5

Engine MPDr.

SECTION 2 SYSTEM Group 2 Control System HST Pump Control The HST pump control consists of the followings. x Forward/Reverse Lever Control

T2-2-6

SECTION 2 SYSTEM Group 2 Control System HST Pump Control System Layout 1 a 2

6 4 5

10 9

8 T4FJ-02-02-004

From Battery

123-

Forward/Reverse Lever MC Reverse Side Solenoid Valve

456-

Forward/Reverse Control Solenoid Valve Forward Side Solenoid Valve HST Filter

789-

T2-2-7

HST Charging Pump Displacement Angle Control Cylinder Engine

10- HST Pump

SECTION 2 SYSTEM Group 2 Control System Forward/Reverse Lever Control Purpose: The forward/reverse lever control controls HST pump (10) displacement angle direction and selects the y port of HST pump (10) according to the signals from forward/ reverse lever (1).

y Forward/Reverse Lever Neutral (N) Position Operation: 1. When forward/reverse lever (1) is in the neutral (N) position (b), current flows from terminal N in forward/reverse lever (1) to MC (2). 2. As MC (2) does not activate forward side solenoid valve (5) and reverse side solenoid valve (3) of forward/reverse control solenoid valve (4) of HST pump (10), forward/reverse control solenoid valve (4) is held in the neutral position. 3. Left and right spring chambers of displacement angle control cylinder (8) of HST pump (10) connect to the neutral circuit in forward/reverse control solenoid valve (4). 4. As the pressure routed to both right and left spring chambers of displacement angle control cylinder (8) are equal, HST pump (10) displacement angle tilts to neither the forward nor reverse position so that pressure oil is not ed from HST pump (10).

T2-2-8

SECTION 2 SYSTEM Group 2 Control System

1 a

6 4 5

10 9

8 T4FJ-02-02-005

From Battery

Neutral (N) Position

123-

Forward/Reverse Lever MC Reverse Side Solenoid Valve

Forward/Reverse Control Solenoid Valve Forward Side Solenoid Valve HST Filter

56-

789-

T2-2-9

HST Charging Pump Displacement Angle Control Cylinder Engine

10- HST Pump

SECTION 2 SYSTEM Group 2 Control System y Forward/Reverse Lever Forward (F) Position Operation: 1. When forward/reverse lever (1) is set in the forward (F) position (c), current flows from terminal F in forward/reverse lever (1) to MC (2). 2. MC (2) activates forward side solenoid valve (5) of forward/reverse control solenoid valve (4) of HST pump (10). 3. Pressure oil from HST charge pump (7) is routed to the spring chamber of displacement angle control cylinder (8) on forward side of HST pump (10) through forward/reverse control solenoid valve (4). 4. Pressure oil ed from HST pump (10) flows to port A (d) in the HST motor through y port B and rotates the HST motor forward.

T2-2-10

SECTION 2 SYSTEM Group 2 Control System

c a

6 4 5

10 9

7 e

8 T4FJ-02-02-006

From Battery

Forward (F) Position

To HST Motor (Port A)

123-

Forward/Reverse Lever MC Reverse Side Solenoid Valve

Forward/Reverse Control Solenoid Valve Forward Side Solenoid Valve HST Filter

78-

HST Charging Pump Displacement Angle Control Cylinder Engine

10- HST Pump

56-

T2-2-11

From HST Motor (Port B)

SECTION 2 SYSTEM Group 2 Control System y Forward/Reverse Lever Reverse (R) Position Operation: 1. When forward/reverse lever (1) is set in the reverse (R) position (f ), current flows from terminal R in forward/reverse lever (1) to MC (2). 2. MC (2) activates reverse side solenoid valve (3) of forward/reverse control solenoid valve (4) of HST pump (10). 3. Pressure oil from HST charge pump (7) is routed to the spring chamber of displacement angle control cylinder (8) on reverse side of HST pump (10) through reverse side solenoid valve (3). 4. Pressure oil ed from HST pump (10) flows to port B (h) in the HST motor through y port A and rotates the HST motor in reverse.

T2-2-12

SECTION 2 SYSTEM Group 2 Control System

1 a

10 9

7 h

8 T4FJ-02-02-007

From Battery

Reverse (R) Position

From HST Motor (Port A)

123-

Forward/Reverse Lever MC Reverse Side Solenoid Valve

Forward/Reverse Control Solenoid Valve Forward Side Solenoid Valve HST Filter

78-

HST Charging Pump Displacement Angle Control Cylinder Engine

10- HST Pump

56-

T2-2-13

To HST Motor (Port B)

SECTION 2 SYSTEM Group 2 Control System HST Brake When traveling 1. During the normal travel condition by using accelerator pedal (2), pressure oil ed from HST pump (6) rotates HST motor (7) and the machine travels. 2. When accelerator pedal (2) is released to reduce speed, the machine has tendency to keep moving at constant speed by inertia force. HST motor (7) is rotated by transformed inertia force through tire, axle and transmission. 3. Pressure oil flow rate flowing from HST motor (7) to HST pump (6) becomes larger than the flow rate ed from HST pump (6). 4. Delivery pressure from HST motor (7) to HST pump (6) increases. HST motor (7) functions as a pump, and HST pump (6) is rotated as a hydraulic motor. 5. Rotation of HST pump (6) rotates engine (9) through shaft (8), and it functions as a engine brake.

T2-2-14

SECTION 2 SYSTEM Group 2 Control System When traveling (Forward)

3 4

9 8

TNCC-02-02-101

From Transmission

123-

Accelerator Pedal Sensor Accelerator Pedal Forward/Reverse Lever

45-

MC Forward/Reverse Control Solenoid Valve

678-

T2-2-15

HST Pump HST Motor Shaft

9- Engine 10- ECM

SECTION 2 SYSTEM Group 2 Control System When stopping 1. When the machine is stopping, the displacement angle control cylinder of HST pump (6) is in the neutral position and pressure oil is not ed to HST motor (7). 2. On a slope, descending force in proportion to the machine weight and slope gradient is applied to the machine. 3. Descending force is transmitted from the tire, axle, transmission (a) to HST motor (7), however, pressure oil does not flow into HST pump (6), thus pressure oil between HST pump (6) and HST motor (7) circuit is compressed and pressure increases. 4. As this pressure acts like a brake which balances out with descending force, the machine stops. 5. As oil leak between HST pump (6) and HST motor (7) circuit rotates HST motor (7), the parking brake is required to completely stop the machine.

T2-2-16

SECTION 2 SYSTEM Group 2 Control System When stopping

3 4

9 8

TNCC-02-02-102

From Transmission

123-

Accelerator Pedal Sensor Accelerator Pedal Forward/Reverse Lever

45-

MC Forward/Reverse Control Solenoid Valve

678-

T2-2-17

HST Pump HST Motor Shaft

9- Engine 10- ECM

SECTION 2 SYSTEM Group 2 Control System When inching operation 1. During the operation of front attachment and driving the machine at a same time, accelerator pedal (2) is depressed to increase the power of front attachment machine speed is also increased. 2. When brake pedal (5) is depressed, declutch valve (14) which is linked brake pedal (5) is operated and displacement angle control pressure oil in HST pump (8) is routed to the hydraulic oil tank. 3. Flow rate of pressure oil flowing from declutch valve (14) to the hydraulic oil tank is increased according to the depressing amount of brake pedal (5), the displacement angle control pressure of HST pump (8) decreases. 4. The displacement angle control cylinder of HST pump (8) moves toward the neutral position, HST pump (8) delivery flow rate decreases. 5. As pressure oil flow rate flowing from HST pump (8) to HST motor (11) decreases, HST motor (11) speed decreases. 6. Therefore, the machine speed decreases.

T2-2-18

SECTION 2 SYSTEM Group 2 Control System When inching operation

2 5

3 4

14 7

8 9 10

TNCC-02-02-102

To Transmission

Depressing

1234-

Accelerator Pedal Sensor Accelerator Pedal Forward/Reverse Lever MC

567-

Brake Pedal Front Attachment Circuit Forward/Reverse Control Solenoid Valve

891011-

T2-2-19

HST Pump Priority Valve Main Pump HST Motor

12- Engine 13- ECM 14- Declutch Valve

SECTION 2 SYSTEM Group 2 Control System HST Motor Control The HST motor control consists of the followings. x Driving Slow Speed Selection Control x Traction Force Limit Control x Traction Control x Overrun Limit Control x Engine Protection Control x Overheat Prevention Control x Driving Slow Speed Switching Shock Reduction Control

T2-2-20

SECTION 2 SYSTEM Group 2 Control System 1

4 11

6 14

13 12

15 9 17

16 20 TNCC-02-02-001

1234567-

Machine Speed Sensor Forward/Reverse Lever Shift Switch Slow Speed (L) Select Switch Traction Control Switch Power Mode Switch MC

891011-

Monitor Controller CAN Coolant Temperature Sensor Pressure Sensor (Front Attachment Pressure) 12- HST Circuit Pressure Sensor

13- Displacement Angle Control Solenoid Valve 14- Driving Control Solenoid Valve 15- HST Motor 16- Displacement Angle Control Cylinder 17- ECM

T2-2-21

18- Engine 19- HST Pump 20- Shaft

SECTION 2 SYSTEM Group 2 Control System Driving Slow Speed Selection Control (only Cab Spec. Machine)

Purpose: Machine speed in slow-speed driving is optimized. IMPORTANT: This control functions when shift switch (3) is set in slow position (4) while driving forward. Operation: 1. Slow Speed (L) Select Switch (5) sends voltage signal according to the rotation angle to MC (6). B C

2. MC (6) calculates the machine speed according to the voltage signals sent from machine speed sensor (1) and slow speed (L) select switch (5).

D TNCC-02-02-002 A-

3. MC (6) activates displacement angle control solenoid valve (7) according to the machine speed.

C-

4. Pressure oil from HST motor (8) is routed to displacement angle control cylinder (9) of HST motor (8) through displacement angle control solenoid valve (7). 5. Displacement angle control cylinder (9) sets HST motor (8) to the displacement angle according to the machine speed. 6. Consequently, the rotation speed of HST motor (8) is changed to the selected speed of slow (L) driving speed limit switch (5) while driving in slow speed.

T2-2-22

HST Motor Displacement Angle 7 km/h (4.3 mph)

BD-

Machine Speed 11.5 km/h (7 mph)

SECTION 2 SYSTEM Group 2 Control System 1 2 a

6 3 4 a

8 b

TNCC-02-02-003

From Battery

To HST Pump (Port A)

From HST Pump (Port B)

123-

Machine Speed Sensor Forward/Reverse Lever Shift Switch

456-

Slow Speed Position Slow Speed (L) Select Switch MC

Displacement Angle Control Solenoid Valve HST Motor

T2-2-23

Displacement Angle Control Cylinder

SECTION 2 SYSTEM Group 2 Control System Traction Force Limit Control Purpose: The traction force limit control controls the displacement angle of HST motor (5) to change the machine traction force and keeps machine speed.

Operation: 1. When turning power mode switch (1) ON, power mode switch (1) sends signals to MC (3). 2. MC (3) calculates matching value according to the signals sent from pressure sensor (front attachment pressure) (2). 3. MC (3) activates displacement angle control solenoid valve (4) of HST motor (5) according to the matching value. 4. Pressure oil from HST motor (5) is routed to displacement angle control cylinder (6) of HST motor (5) through displacement angle control solenoid valve (4). 5. Displacement angle control cylinder (6) sets the displacement angle of HST motor (5) to the matching value calculated by MC (3). 6. Therefore, y pressure of HST motor (5) changes and the maximum traction force is reduced.

T2-2-24

SECTION 2 SYSTEM Group 2 Control System

2 3 1

7 9

8 6

TNCC-02-02-004

From Battery

12-

Power Mode Switch Pressure Sensor (Front Attachment Pressure)

34-

MC Displacement Angle Control Solenoid Valve

56-

T2-2-25

HST Motor Displacement Angle Control Cylinder

789-

HST Pump Shaft Engine

SECTION 2 SYSTEM Group 2 Control System Traction Control Purpose: The traction control improves work efficiency by controlling the maximum displacement angle of HST motor (4) and changing the machine maximum traction force to prevent tires from slipping on a slippy surface.

Operation: 1. When turning traction control switch (2) ON, traction control switch (2) sends the signals to MC (3). 2. MC (3) calculates traction control value according to the voltage signals sent from pressure sensor (front attachment pressure) (1) and traction control switch (2). 3. MC (3) activates the displacement angle control solenoid valve of HST motor (4) according to the traction control value. 4. Pressure oil from HST motor (4) is routed to displacement angle control cylinder (5) of HST motor (4) through displacement angle control solenoid valve (6). 5. Displacement angle control cylinder (5) sets the displacement angle of HST motor (4) to the displacement angle of traction control value calculated by MC (3). 6. Therefore, y pressure of HST motor (4) changes and the maximum traction force is changed.

T2-2-26

SECTION 2 SYSTEM Group 2 Control System

3 1

a b

TNCC-02-02-005

From Battery

From Key Switch Terminal M

To HST Pump (Port A)

From HST Pump (Port B)

Pressure Sensor (Front Attachment Pressure) Traction Control Switch

34-

MC HST Motor

Displacement Angle Control Cylinder

Displacement Angle Control Solenoid Valve

T2-2-27

SECTION 2 SYSTEM Group 2 Control System Overrun Limit Control Purpose: When the machine speed exceeds allowable speed, the overrun limit control controls the machine speed to the maximum allowable speed by controlling the displacement angle of HST motor (4).

Operation: 1. MC (2) calculates the machine speed according to the signals from machine speed sensor (1). 2. When machine speed exceeds the allowable speed, MC (2) activates displacement angle control solenoid valve (3). 3. Pressure oil from HST pump (6) is divided in HST motor (4); one route rotates HST motor (4) and another route is routed to displacement angle control cylinder (5) of HST motor (4) through the displacement angle control solenoid valve. 4. Displacement angle control solenoid valve (3) controls pressure of pressure oil routed to displacement angle control cylinder (5) according to the signals from MC (2); displacement angle control cylinder (5) gradually increases displacement angle of HST motor (4). 5. Rotation speed of HST motor (4) is decreased until machine speed reduces to the maximum allowable speed.

T2-2-28

SECTION 2 SYSTEM Group 2 Control System 1

3 8

T4FJ-02-02-030

12-

Machine Speed Sensor MC

34-

Displacement Angle Control Solenoid Valve HST Motor

56-

T2-2-29

Displacement Angle Control Cylinder HST Pump

78-

Engine ECM

SECTION 2 SYSTEM Group 2 Control System Engine Protection Control Purpose: When the engine speed exceeds allowable maximum speed, the engine protection control prevents the engine overspeed by controlling the displacement angle of HST motor (3) and reducing the HST brake force.

A G

Operation: 1. When engine speed exceeds 2850 min-1, ECM (8) sends the engine speed signal to MC (1) by using CAN communication (9).

B F

T4FJ-02-02-012

2. MC (1) activates displacement angle control solenoid valve (2) by calculating the displacement angle of HST motor (3) according to the engine speed signal. 3. Displacement angle control solenoid valve (2) gradually decreases pressure of pressure oil routed to displacement angle control cylinder (4) of HST motor (3) according to the signals from MC (1).

ABCDE-

4. Pressure oil from driving control solenoid valve (10) acts on displacement angle control cylinder (4), which gradually reduce the displacement angle of HST motor (3). 5. As pressure oil flow rate flowing from HST motor (3) to HST pump (5) gradually decreases, suction pressure of HST pump (5) also decreases. 6. Consequently, HST pump (5) speed decreases and HST brake force decreases. The engine over speed prevented by the HST brake force decrease.

T2-2-30

Displacement Angle Machine Speed Maximum Minimum Speed before Control

FGH-

Speed after Control Displacement Angle before Control Displacement Angle after Control

SECTION 2 SYSTEM Group 2 Control System

2 8

T4FJ-02-02-013

12-

MC Displacement Angle Control Solenoid Valve

34-

HST Motor Displacement Angle Control Cylinder

567-

T2-2-31

HST Pump Shaft Engine

8- ECM 9- CAN 10- Driving Control Solenoid Valve

SECTION 2 SYSTEM Group 2 Control System Overheat Prevention Control Purpose: When the coolant temperature and HST oil temperature rise abnormally, the overheat prevention control prevents abnormal rise of coolant temperature by limiting minimum displacement angle of HST motor (6), reducing HST motor (6) speed and reducing the machine speed.

Operation: 1. ECM (2) receives the signals from coolant temperature sensor (1). 2. ECM (2) sends the coolant temperature signals to MC (4) by using CAN communication (3). 3. Signals from HST oil temperature sensor (9) is sent to monitor controller (8). 4. Monitor controller (8) sends HST oil temperature signals to MC (4) by using CAN communication (3). 5. MC (4) activates displacement angle control solenoid valve (5) by calculating the displacement angle of HST motor (6). 6. Pressure oil from HST motor (6) is routed to displacement angle control cylinder (7) of HST motor (6) through displacement angle control solenoid valve (5). 7. Displacement angle control cylinder (7) increases displacement angle of HST motor (6). 8. Therefore, the rotation speed of HST motor (6) is decreased and the machine speed is decelerated. 9. As the HST pump speed is also decreased and engine load is decreased, rise of the coolant and HST oil temperature is reduced.

T2-2-32

SECTION 2 SYSTEM Group 2 Control System

B a

A b

TNCC-02-02-006

To HST Pump (Port A)

From HST Pump (Port B)

123-

Coolant Temperature Sensor ECM CAN

45-

MC Displacement Angle Control Solenoid Valve

67-

T2-2-33

HST Motor Displacement Angle Control Cylinder

89-

Monitor Controller HST Oil Temperature Sensor

SECTION 2 SYSTEM Group 2 Control System Driving Slow Speed Switching Shock Reduction Control Purpose: The driving slow speed switching shock reduction control reduces the clutch connection shock by reducing the HST brake force when the driving mode is changed from high to slow speed.

Operation: x Forward Operation 1. When forward/reverse lever (2) is set to forward (F) position (3), MC (4) activates driving control solenoid valve (5) to the forward side. 2. When shift switch (1) is set to the slow speed position, MC (4) shifts the transmission to the slow speed position according to the driving slow speed selection control. (Refer to Driving Slow Speed Selection Control) 3. As the rotation speed of the HST pump does not change due to the HST brake, the machine speed is maintained. 4. Pressure oil flows from port B (c) of the HST pump to port A of HST motor (6), and pressure oil is divided in HST motor (6); one route rotates HST motor (6) and another route is routed to displacement angle control cylinder (7) of HST motor (6) through travel control solenoid valve (5). 5. Displacement angle control cylinder (7) changes the displacement angle of HST motor (6) from minimum to 1/4. 6. As y pressure from port B of HST motor (6) to port A (b) of the HST pump reduces, the HST brake force reduces. 7. Rotation speed of the HST pump reduces and the machine speed is decelerated.

T2-2-34

SECTION 2 SYSTEM Group 2 Control System 3

4 2

c A

TNCC-02-02-007

From Battery

To HST Pump (Port A)

From HST Pump (Port B)

123-

Shift Switch Forward/Reverse Lever Forward (F) Position

456-

MC Driving Control Solenoid Valve HST Motor

Displacement Angle Control Cylinder

T2-2-35

SECTION 2 SYSTEM Group 2 Control System x Reverse Operation 1. When forward/reverse lever (2) is set to reverse (R) position (3), MC (4) activates driving control solenoid valve (5) to the reverse side. 2. When shift switch (1) is set to the slow speed position, MC (4) shifts the transmission to the slow speed position according to the driving slow speed selection control. (Refer to Driving Slow Speed Selection Control) 3. As the rotation speed of the HST pump does not change due to the HST brake, the machine speed is maintained. 4. Pressure oil flows from port A (b) of the HST pump to port B of HST motor (6), and pressure oil is divided in HST motor (6); one route rotates HST motor (6) and another route is routed to displacement angle control cylinder (7) of HST motor (6) through travel control solenoid valve (5). 5. Displacement angle control cylinder (7) changes the displacement angle of HST motor (6) from minimum to 1/4. 6. As y pressure from port A of HST motor (6) to port B (c) of the HST pump reduces, the HST brake force reduces. 7. Rotation speed of the HST pump reduces and the machine speed is decelerated.

T2-2-36

SECTION 2 SYSTEM Group 2 Control System 3

4 2

TNCC-02-02-008

From Battery

From HST Pump (Port A)

To HST Pump (Port B)

123-

Shift Switch Forward/Reverse Lever Reverse (R) Position

456-

MC Driving Control Solenoid Valve HST Motor

Displacement Angle Control Cylinder

T2-2-37

SECTION 2 SYSTEM Group 2 Control System Transmission Control The transmission control consists of the followings. x Driving Slow Mode Selection Control Transmission Control System Layout 2

3 1 4

T4FJ-02-02-015

123-

Shift Switch Machine Speed Sensor MC

45-

Quick Shift Switch Transmission

67-

T2-2-38

Driving Mode Selection Solenoid Valve Driving Mode Selection Valve

SECTION 2 SYSTEM Group 2 Control System (Blank)

T2-2-39

SECTION 2 SYSTEM Group 2 Control System Driving Slow Speed Selection Control Purpose: The driving slow speed selection control shifts the machine speed to the slow speed.

Slow Speed Selection by using Shift Switch (1) Operation: 1. When shift switch (1) is set to the Lo position, current from terminal Lo (2) of shift switch (1) flows to MC (3). 2. MC (3) activates travel mode selector solenoid valve (7). 3. Pressure oil flowing from brake/transmission pump (a) is routed to driving mode selection valve (8) through driving mode selection solenoid valve (7), driving mode selector valve (8) is sifted. 4. Pressure oil flowing from brake/transmission pump (a) is routed to clutch slow speed side (6) through driving mode selection valve (8), the clutch is shifted to the slow speed.

T2-2-40

SECTION 2 SYSTEM Group 2 Control System

b 1 4

7 a

T4FJ-02-02-016

From Brake/ Transmission Pump

From Battery

123-

Shift Switch Terminal Lo MC

456-

Quick Shift Switch Transmission Slow Speed Side

78-

T2-2-41

Driving Mode Selection Solenoid Valve Driving Mode Selection Valve

SECTION 2 SYSTEM Group 2 Control System Slow Speed Selection by using Quick Shift Switch (4) Operation: 1. When quick shift switch (4) is pushed with shift switch (2) is in Hi position and the machine speed is 10 km/h (6.2 mph) or lower, MC (3) activates travel mode selector solenoid valve (7). 2. Pressure oil flowing from brake/transmission pump (a) is routed to travel mode selector valve (9) through drive mode selection solenoid valve (7), thus travel mode selector valve (9) is sifted. 3. Pressure oil flowing from brake/transmission pump (a) is routed to clutch slow speed side (6) through drive mode selection valve (9), the clutch is shifted to the slow speed. 4. When quick shift switch (4) is pushed again, MC (3) deactivates drive mode selection solenoid valve (7). 5. Drive mode selection valve (9) is shifted by spring (8). 6. Pressure oil flowing from brake/transmission pump (a) is routed to clutch high speed side (10) through drive mode selection valve (9), the clutch is shifted to the high speed.

T2-2-42

SECTION 2 SYSTEM Group 2 Control System

3 2

4 b

5 6 10

7 a

T4FJ-02-02-017 a-

From Brake/ Transmission Pump

From Battery

1234-

Machine Speed Sensor Shift Switch MC Quick Shift Switch

567-

Transmission Slow Speed Side Driving Mode Selection Solenoid Valve

8- Spring 9- Driving Mode Selection Valve 10- Fast Speed Side

T2-2-43

SECTION 2 SYSTEM Group 2 Control System Other Controls The other control consists of the followings. x Backup Light Lighting Control x Ride Control Function (Option) x Parking Brake Operation Indicator Control x Secondary Steering Control (Option) x Bucket Auto Leveler Control x Lift Arm Float Control (Option) (Hydraulic Pilot Type) x Lift Arm Kickout Control (Option) (Hydraulic Pilot Type)

T2-2-44

SECTION 2 SYSTEM Group 2 Control System (Blank)

T2-2-45

SECTION 2 SYSTEM Group 2 Control System Backup Light Lighting Control 1. When forward/reverse lever (1) is set to reverse (R) position (b), MC (2) excites back buzzer relay (4). 2. Therefore, current from fuse #2 (3) in fuse box A flows to backup lights (6) in the rear combination lights through back buzzer relay (4), backup lights (6) light. 3. At the same time, current from back buzzer relay (4) flows to backup buzzer (5) and backup buzzer (5) sounds.

a 3

From Battery

Reverse (R) Position

12-

Forward/Reverse Lever MC

34-

Fuse Box A, Fuse #2 Back Buzzer Relay

56-

T2-2-46

Backup Buzzer Backup Light

T4FJ-02-02-018

SECTION 2 SYSTEM Group 2 Control System (Blank)

T2-2-47

SECTION 2 SYSTEM Group 2 Control System Ride Control Function (Option) Purpose: The ride control function reduces machine vibration while driving on a rough road to reduce operator's fatigue by forming a damper circuit in lift arm cylinder (9). IMPORTANT: When ride control switch (6) or ride control solenoid valve (11) become abnormal, the ride control function is deactivated.

Operation: 1. When ride control switch (6) is turned in AUTO, ride control switch (6) sends the signals to MC (2). 2. MC (2) sends the ride control switch (6) AUTO signal to monitor controller (4) by using CAN communication (3). 3. Monitor controller (4) displays the ride control indicator on the monitor panel. 4. Signal from machine speed sensor (1) is sent to MC (2) and is converted to a machine speed data. 5. When the machine speed exceeds 6 km/h (3.7 mph), MC (2) activates ride control solenoid valve (11). 6. Pressure oil from HST charging pump (c) flows to spool (13) through ride control solenoid valve (11) and moves spool (13) in ride control valve (10). 7. When spool (13) moves, a damper circuit is formed between rod side and bottom side of lift arm cylinder (9). 8. When the machine travels on a rough road, ride control accumulator (12) absorbs bottom pressure change of lift arm cylinder (9), mechanical shock on whole machine is reduced. 9. When the machine speed becomes 4 km/h (2.5 mph) or less, the ride control function is deactivated. IMPORTANT: When the machine speed is 6 km/h (3.7 mph) or less, the ride control function is not activated.

T2-2-48

SECTION 2 SYSTEM Group 2 Control System

1 3

a 7 8 a

9 b

c 12

13 TNCC-02-02-009

From Battery

To Control Valve

12345-

Machine Speed Sensor MC CAN Monitor Controller Fuse Box 1 Fuse #1

678910-

Ride Control Switch Light Switch Fuse Box 1 Fuse #17 Lift Arm Cylinder Ride Control Valve

11- Ride Control Solenoid Valve 12- Ride Control Accumulator 13- Spool

T2-2-49

From HST Charging Pump

SECTION 2 SYSTEM Group 2 Control System Parking Brake Operation Indicator Control Purpose: The parking brake operation indicator control lights the parking brake indicator on monitor controller (3) when the parking brake is applied. Also, the control cancels forward/reverse lever (1) operation signals in order to prevent parking brake dragging and sounds an alarm on monitor controller (3) when forward/reverse lever (1) is operated while the parking brake is applied.

y Parking Brake Switch: ON position Operation: 1. When the parking brake switch is in the ON position, parking brake solenoid valve (8) is not activated and release pressure is not applied to the parking brake.

y Parking Brake Switch: OFF Position Operation: 1. When the parking brake switch is in the OFF position, parking brake solenoid valve (8) activates and release pressure is applied to the parking brake. 2. Therefore, the parking brake circuit pressure increases and the parking brake is released.

2. Therefore, the parking brake circuit pressure is reduced.

3. When the parking brake circuit pressure increases, parking brake sensor (7) does not send the voltage signals to monitor controller (3).

3. When the parking brake circuit pressure falls below the specified value, parking brake sensor (7) sends the signals to monitor controller (3).

4. Monitor controller (3) turns off the parking brake indicator.

4. Monitor controller (3) lights the parking brake indicator.

NOTE: Refer to SYSTEM / Electrical System for the 5. When forward/reverse lever (1) is set to forward (F) or reverse (R) position, MC (2) sends the forward/ reverse lever (1) position signal to monitor controller (3) by using CAN communication (4). 6. Monitor controller (3) sounds the buzzer and gives warning to the operator. 7. In addition, a signal which lights the parking brake indicator is sent from terminal #2-11 in monitor controller (3) to terminal #21 in MC (2). 8. MC (2) cancels forward (F) or reverse (R) position signal sent from forward/reverse lever (1).

parking brake operation circuit. IMPORTANT: When parking brake sensor (7) becomes abnormal, monitor controller (3) holds the parking brake indicator OFF even the parking brake switch is set to the ON position and the parking brake is applied. At the same time, as the parking brake indicator lighting signal from monitor controller (3) to MC (2) is stopped, MC (2) is possible to control forward/reverse control solenoid valve (10) in the HST pump. Consequently, be sure that the machine travel operation may be possible even if the parking brake is applied.

9. As current does not flow through forward side solenoid valve (9) or reverse side solenoid valve (11) in forward/reverse control solenoid valve (4), the machine will not move to forward or reverse.

T2-2-50

SECTION 2 SYSTEM Group 2 Control System

#2-11

3 1 #21

10 7

c b

TNCC-02-02-010

From Brake/ Transmission Pump

From HST Charging Pump

To HST Pump Displacement Angle Cylinder

123-

Forward/Reverse Lever MC Monitor Controller

456-

CAN Transmission Parking Brake

789-

Parking Brake Pressure Sensor Parking Brake Solenoid Valve Forward Side Solenoid Valve

NOTE: Refer to Electrical System for the parking brake operation circuit.

T2-2-51

10- Forward/Reverse Control Solenoid Valve 11- Reverse Side Solenoid Valve

SECTION 2 SYSTEM Group 2 Control System Secondary Steering Control (Option) Purpose: When hydraulic pressure oil cannot be supplied to the steering circuit due to the engine fault, the steering operation cannot be made. The secondary steering control activates secondary steering pump (8) for a while, and makes the steering operation possible. IMPORTANT: Large capacity of electricity is required in order to operate secondary steering pump (8). Check secondary steering pump (8) within 1 or 2 seconds. y Operation of secondary steering pump (8) by operating secondary steering check switch (6) (option) Operation: 1. When secondary steering check switch (6) is set to the ON position, current from terminal #1-33 in monitor controller (4) flows to the ground circuit through secondary steering check switch (6). 2. Monitor controller (4) connects the ground circuit of secondary steering pump relay (5) while current flows from terminal #1-33 in monitor controller (4) to the ground circuit, thus secondary steering pump relay (5) is excited continuously. 3. Monitor controller (4) lights the secondary steering indicator while secondary steering pump relay (5) is excited. 4. Current from battery (a) flows to secondary steering motor (7) through secondary steering pump relay (5) and operates secondary steering pump (8). 5. Pressure oil from secondary steering pump (8) is supplied to steering circuit (b) and makes the steering operation possible for a while.

T2-2-52

SECTION 2 SYSTEM Group 2 Control System

3 4 2 #1-33

5 6

b 9

8 c

TNCC-02-02-011

From Battery

To Steering Circuit

From Main Pump

1234-

Machine Speed Sensor MC CAN Monitor Controller

Secondary Steering Pump Relay Secondary Steering Check Switch

789-

Secondary Steering Motor Secondary Steering Pump Steering Pressure Switch

T2-2-53

SECTION 2 SYSTEM Group 2 Control System y Operation of secondary steering pump when steering oil circuit is malfunctioning 1. Current flowing from steering pressure switch (9) to monitor controller (4) stops when machine speed is 5 km/h (3.1 mph) or more and the steering cannot be operated. 2. Monitor controller (4) connects secondary steering pump relay (5) to the ground and secondary steering pump relay (5) is excited. 3. Monitor controller (4) lights the secondary steering indicator and sounds buzzer while secondary steering pump relay (5) is excited. 4. Current from battery (a) flows to secondary steering motor (7) through secondary steering pump relay (5) and operates secondary steering pump (8). 5. Pressure oil from secondary steering pump (8) is supplied to the steering circuit (b) and makes the steering operation possible for a while.

T2-2-54

SECTION 2 SYSTEM Group 2 Control System

3 4

7 8

TNCC-02-02-012

From Battery

To Steering Circuit

From Main Pump

1234-

Machine Speed Sensor MC CAN Monitor Controller

Secondary Steering Pump Relay Secondary Steering Check Switch

789-

Secondary Steering Motor Secondary Steering Pump Steering Pressure Switch

T2-2-55

SECTION 2 SYSTEM Group 2 Control System Bucket Auto Leveler Control Purpose: The bucket auto leveler control automatically tilts the bucket at an appropriate angle (horizontal) to start digging in returning the bucket to the tilting position.

y Manually Operated Type Operation: 1. Bar (3) is located in front of bucket proximity switch (2) during dumping operation of the bucket. While bar (3) passes by bucket proximity switch (2), bucket proximity switch (2) is turned ON. 2. Therefore, current from battery (a) excites bucket tilt coil (4) of bucket spool (5). 3. When the bucket control lever is moved to the bucket tilting detent position (position to move farther than the tilting position), bucket spool (5) is held to the detent position by bucket tilt coil (4) of bucket spool (5). 4. Pressure oil from main pump (c) flows to the bottom side of bucket cylinder (1) through bucket spool (5) in control valve (6) and tilts the bucket. 5. At the same time, bar (3) passes by bucket proximity switch (2). When bar (3) becomes distant from bucket proximity switch (2), bucket proximity switch (2) is turned OFF and bucket tilt coil (4) is unexcited. 6. Therefore, bucket spool (5) in control valve (6) also returns to neutral (N) position (d), bucket cylinder (1) stops. 7. Consequently, the bucket tilting operation is stopped automatically.

T2-2-56

SECTION 2 SYSTEM Group 2 Control System

5 3

b 4 TNCC-02-02-013

ab-

From Battery To Hydraulic Oil Tank

cd-

From Main Pump Neutral (N) Position

Bucket Tilting Position

12-

Bucket Cylinder Bucket Proximity Switch

34-

Bar Coil (Bucket Tilt)

56-

Bucket Spool Control Valve

T2-2-57

SECTION 2 SYSTEM Group 2 Control System y Hydraulic Operated Type (Option) Operation: 1. Bar (3) is located in front of bucket proximity switch (2) during dumping operation of the bucket. While bar (3) passes by bucket proximity switch (2), bucket proximity switch (2) is turned ON.

7. At the same time, bar (3) passes by bucket proximity switch (2). 8. When bar (3) becomes distant from bucket proximity switch (2), bucket proximity switch (2) is turned OFF, bucket leveler relay (6) (coil side) is disconnect from the ground, and bucket leveler relay (6) is turned OFF.

2. Bucket leveler relay (6) (coil side) is connected to the ground through bucket proximity switch (2). Then, bucket leveler relay (6) turns ON. 3. Coil (5) on the bucket tilting side is connected to the ground through bucket leveler relay (6) (contact side).

9. As coil (5) on the bucket tilting side is disconnect from the ground, it is unexcited.

4. Current from battery (a) flows to coil (5) on the bucket tilting side and excites coil (5) on the bucket tilting side.

10. Therefore, the bucket control lever is returned to neutral (N) position (c). As bucket spool (7) in control valve (8) also returns to neutral (N) position (c), bucket cylinder (1) stops.

5. When the bucket control lever is moved farther than the bucket tilting detent position (position to move farther than the tilting position), the bucket control lever is held by coil (5) on the bucket tilting side and pressure oil from pilot valve (4) moves bucket spool (7) in control valve (8).

11. Consequently, the bucket tilting operation is stopped automatically.

6. Pressure oil from main pump (e) flows to the bottom side of bucket cylinder (1) through bucket spool (7) in control valve (8) and tilts the bucket.

T2-2-58

SECTION 2 SYSTEM Group 2 Control System

b a c

7 5

4 c f

d 6 f

e TNCC-02-02-014

ab-

From Battery Bucket Tilting Position

cd-

Neutral (N) Position From HST Charging Pump

ef-

From Main Pump To Hydraulic Oil Tank

123-

Bucket Cylinder Bucket Proximity Switch Bar

Pilot Valve (Bucket Control Lever) Coil on Bucket Tilting Side

678-

Bucket Leveler Relay Bucket Spool Control Valve

T2-2-59

SECTION 2 SYSTEM Group 2 Control System Lift Arm Float Control (Hydraulic Pilot Type) (Option) Purpose: Free raising and lowering of the lift arm in response to the external load for snow removing and road cleaning

Operation: 1. When the lift arm control lever is moved to the floating position (farther position than the lift arm lower position), the lift arm control lever is held by coil (2) on the lift arm lower side.

NOTE: Coil (2) on the lift arm lower side is always excited by current from battery (a) with the key ON. 2. Pressure oil from pilot valve (3) moves lift arm spool (5) in control valve (4) to the floating position (b). 3. Pressure oil from main pump (f ) flows to the neutral circuit through lift arm spool (5). In addition, the circuits on bottom and rod sides in lift arm cylinder (1) are connected in lift arm spool (5). Then, it is connected to hydraulic oil tank (11). 4. Therefore, as the circuit pressure between lift arm cylinder (1) and hydraulic oil tank (b) becomes same, the lift arm can move freely depending on the external force. 5. The lift arm control lever returns to the neutral (N) position (c) if pulled more strongly than the magnetic force of coil (2) on the lift arm lowering side. 6. Therefore, lift arm spool (5) in control valve (4) returns to the neutral (N) position and the lift arm float control is deactivated.

T2-2-60

SECTION 2 SYSTEM Group 2 Control System 1

a 2 c

3 5

4 d

TNCC-02-02-015

ab-

From Battery Lift Arm Float Position

cd-

Neutral (N) Position To Hydraulic Oil Tank

ef-

From HST Charging Pump From Main Pump

12-

Lift Arm Cylinder Coil on Lift Arm Lower Side

Pilot Valve (Lift Arm Control Lever) Control Valve

Lift Arm Spool

T2-2-61

SECTION 2 SYSTEM Group 2 Control System Lift Arm Kickout Control (Hydraulic Pilot Type) (Option) Purpose: The lift arm kickout control automatically stops raising the lift arm at any height when returning the lift arm to the highest position. Operation: 1. Plate (3) is located in front of lift arm proximity switch (2) when the bucket is lowered. While plate (3) passes by lift arm proximity switch (2), lift arm proximity switch (2) is turned ON.

7. At the same time, plate (3) passes by lift arm proximity switch (2). 8. When plate (3) becomes distant from lift arm proximity switch (2), lift arm proximity switch (2) is turned OFF, kickout relay (8) (coil side) is disconnect from the ground, and kickout relay (8) is turned OFF.

2. Kickout relay (8) (coil side) is connected to the ground through lift arm proximity switch (2). Then, kickout relay (8) turns ON.

9. As coil (5) on the lift arm raise side is disconnected from the ground, it turned OFF.

3. Coil (5) on the lift arm raise side is connected to the ground through kickout relay (8) (contact side).

10. Therefore, the lift arm control lever is returned to neutral (N) position (c). As lift arm spool (7) in control valve (6) also returns to neutral position (c), lift arm cylinder (1) stops.

4. Current from battery (a) flows to coil (5) on the lift arm raise side and excites coil (5) on the lift arm raise side.

11. Consequently, the lift arm raising operation is stopped automatically.

5. When the lift arm control lever is moved farther than the lift arm raise detent position (position to move farther than the raise position), the lift arm control lever is held by coil (5) on the lift arm raise side and pressure oil from pilot valve (4) moves lift arm spool (7) in control valve (6). 6. Pressure oil from main pump (e) flows to the bottom side of lift arm cylinder (1) through lift arm spool (7) in control valve (6) and raise the lift arm.

T2-2-62

SECTION 2 SYSTEM Group 2 Control System

a c

b 5

8 e f TNCC-02-02-016

ab-

From Battery Lift Arm Raise Position

cd-

Neutral (N) Position From HST Charging Pump

ef-

From Main Pump To Hydraulic Oil Tank

123-

Lift Arm Cylinder Lift Arm Proximity Switch Plate

Pilot Valve (Lift Arm Control Lever) Coil On Lift Arm Raise Side Control Valve

78-

Lift Arm Spool Kickout Relay

56-

T2-2-63

SECTION 2 SYSTEM Group 2 Control System (Blank)

T2-2-64

SECTION 2 SYSTEM Group 3 ECM System Outline ECM (11) receives the signals from sensors and MC (21). ECM (11) processes and activates two-way valve (12), suction control valve (18), and EGR motor (10) in order to control supply pump (16), injector (13), and the EGR valve.

Supply pump (16) is activated by the engine and produces high-pressure fuel. Common rail (15) distributes high-pressure fuel produced by supply pump (16) to injector (13) in each engine cylinder. Injector (13) injects high-pressure fuel from common rail (15).

5 6 2

19 18

16 17

TNCC-02-03-001

234567-

Boost Pressure Sensor Boost Temperature Sensor Coolant Level Switch Crank Speed Sensor Cam Angle Sensor Coolant Temperature Sensor

8910111213-

Engine Oil Pressure Sensor EGR Motor Position Sensor EGR Motor ECM Two-Way Valve Injector

141516171819-

T2-3-1

Common Rail Pressure Sensor Common Rail Supply Pump Fuel Tank Suction Control Valve Fuel Pressure Switch

20- CAN 21- MC

SECTION 2 SYSTEM Group 3 ECM System Fuel Injection Control ECM (11) detects the engine running condition according to the signals from each sensor and MC (21), and controls fuel injection amount, injection pressure, injection timing, and injection rate. Two-way valve (12) controls: x Fuel Injection Amount Control x Fuel Injection Timing Control x Fuel Injection Rate Control Suction control valve (18) controls: x Fuel Injection Pressure Control

T2-3-2

SECTION 2 SYSTEM Group 3 ECM System

5 6 2

19 18

16 17

TNCC-02-03-001

234567-

Boost Pressure Sensor Boost Temperature Sensor Coolant Level Switch Crank Speed Sensor Cam Angle Sensor Coolant Temperature Sensor

8910111213-

Engine Oil Pressure Sensor EGR Motor Position Sensor EGR Motor ECM Two-Way Valve Injector

141516171819-

T2-3-3

Common Rail Pressure Sensor Common Rail Supply Pump Fuel Tank Suction Control Valve Fuel Pressure Switch

20- CAN 21- MC

SECTION 2 SYSTEM Group 3 ECM System Fuel Injection Amount Control Purpose: The fuel injection amount control controls the best fuel injection amount. Operation: 1. ECM (11) detects the engine speed according to the signals from crank Speed sensor (5) and cam angle sensor (6). 2. MC (21) calculates the target engine speed according to the signals from accelerator pedal sensor (23) and power mode switch (22), and sends the signals equivalent to it to ECM (11). (Refer to SYSTEM / Control System.) 3. ECM (11) mainly controls fuel injection amount by turning two-way valve (12) in injector (13) ON/OFF according to the engine speed and the signals from MC (21).

T2-3-4

SECTION 2 SYSTEM Group 3 ECM System

5 23

6 2

22 9

20 21

19 18 13

15 16 17

TNCC-02-03-002

234567-

Boost Pressure Sensor Boost Temperature Sensor Coolant Level Switch Crank Speed Sensor Cam Angle Sensor Coolant Temperature Sensor

8910111213-

Engine Oil Pressure Sensor EGR Motor Position Sensor EGR Motor ECM Two-Way Valve Injector

141516171819-

T2-3-5

Common Rail Pressure Sensor Common Rail Supply Pump Fuel Tank Suction Control Valve Fuel Pressure Switch

20212223-

CAN MC Power Mode Switch Accelerator Pedal Sensor

SECTION 2 SYSTEM Group 3 ECM System Fuel Injection Pressure Control Purpose: The fuel injection pressure control controls the best fuel injection pressure. Operation: 1. ECM (11) calculates fuel injection amount according to the engine speed and the signals from MC (21). (Refer to Fuel Injection Amount Control.) 2. Common rail pressure sensor (14) sends the signals according to pressure in common rail (15) to ECM (11). 3. ECM (11) calculates the best fuel pressure in common rail (15) according to the engine speed, fuel injection amount, and the signals of common rail pressure sensor (14). 4. ECM (11) activates suction control valve (18) in supply pump (16) and supplies the best amount of fuel to common rail (15). 5. Fuel according to fuel pressure in common rail (15) is supplied to injector (13) from common rail (15) so that fuel injection pressure is controlled.

T2-3-6

SECTION 2 SYSTEM Group 3 ECM System

5 23

6 2

22 9

20 21

19 18 13

15 16 17

TNCC-02-03-003

234567-

Boost Pressure Sensor Boost Temperature Sensor Coolant Level Switch Crank Speed Sensor Cam Angle Sensor Coolant Temperature Sensor

8910111213-

Engine Oil Pressure Sensor EGR Motor Position Sensor EGR Motor ECM Two-Way Valve Injector

141516171819-

T2-3-7

Common Rail Pressure Sensor Common Rail Supply Pump Fuel Tank Suction Control Valve Fuel Pressure Switch

20212223-

CAN MC Power Mode Switch Accelerator Pedal Sensor

SECTION 2 SYSTEM Group 3 ECM System Fuel Injection Timing Control

Operation of Fuel Injection: 1. Fuel pressure is always applied to nozzle (6) in the injector.

Purpose: The fuel injection timing control calculates the best fuel injection timing.

2. When turning electromagnetic coil (9) in two-way valve (2) ON, high-pressure fuel in control chamber (5) returns to the fuel tank through orifice A (4).

Operation: 1. ECM calculates the fuel injection timing according to the engine speed and fuel injection amount.

3. Therefore, hydraulic piston (10) is raised and nozzle (6) is opened so that the injection starts.

2. ECM turns two-way valve (2) in the injector ON/OFF according to fuel injection timing. Fuel Injection Rate Control

4. When turning electromagnetic coil (9) in two-way valve (2) OFF, valve (8) is closed and the circuit to the fuel tank is closed. High-pressure fuel from the common rail flows to control chamber (5) through orifice B (12). 5. Therefore, when high-pressure fuel flows to control chamber (5), hydraulic piston (10) is lowered by the pressure difference due to movement of hydraulic piston (10). As nozzle (6) is closed, the injection stops.

Purpose: The fuel injection rate control improves combustion in the engine cylinder. Operation: 1. The injector injects small amount of fuel (pilot injection) first and ignites. 2. After igniting, the injector makes secondary injection (main injection). 3. ECM controls fuel injection timing and fuel injection amount by turning two-way valve (2) in the injector ON/OFF.

T2-3-8

SECTION 2 SYSTEM Group 3 ECM System 1. Two-way valve: ON

2. Injection Start 1

8 7

5 10 11

TDAA-02-03-014

TDAA-02-03-015

3. Two-way valve: OFF

4. Injection Stop 1

1 2

8 7

7 5

TDAA-02-03-017

TDAA-02-03-016

123-

From ECM Two-Way Valve Returning to Fuel Tank

456-

Orifice A Control Chamber Nozzle

789-

T2-3-9

From Common Rail Valve Electromagnetic Coil

10- Hydraulic Piston 11- Spring 12- Orifice B

SECTION 2 SYSTEM Group 3 ECM System EGR Control

NOTE: EGR: Exhaust Gas Recirculation

Purpose: The EGR control re-circulates a part of exhaust gas in intake manifold (12) and combines it with intake-air. Therefore, combustion temperature is lowered and generation of oxide of nitrogen (NOx) is controlled. Operation: x EGR Gas Amount Control 1. ECM (13) decides EGR gas amount according to engine speed, fuel flow rate, coolant temperature, and intake-air temperature. 2. ECM (13) activates EGR motor (10), opens EGR valve (8), and flows EGR gas to intake manifold (12) in response to engine condition so that EGR gas is combined with intake-air. 3. At the same time, ECM (13) detects the opening amount of EGR valve (8) by using EGR motor position sensor (9). x EGR Gas Cooling 1. EGR gas is cooled by cooling system (6) in the EGR gas passage. 2. Cooled EGR gas is combined with intake-air so that combustion temperature is lowered and NOx is generated lower than normal EGR gas.

T2-3-10

SECTION 2 SYSTEM Group 3 ECM System

17 16 15 14

9 10

8 3

5 6 4 7

12 11

TNCC-02-03-004

12345-

From Air Cleaner To Intercooler Exhaust Engine Outlet of Coolant

678910-

Cooling System Inlet of Coolant EGR Valve EGR Motor Position Sensor EGR Motor

1112131415-

T2-3-11

Intake-Air (From Intercooler) Intake Manifold ECM Common Rail Pressure Sensor Coolant Temperature Sensor

16- Cam Angle Sensor 17- Crank Speed Sensor

SECTION 2 SYSTEM Group 3 ECM System Neutral Engine Start Control Purpose: The neutral engine start control prevents the engine from unexpectedly starting out. 1. When key switch (1) is in START position (2), current from battery (3) flows to forward/reverse lever (12) through battery relay (4), fusible link 100 A (8), and fuse #10 in fuse box A (9). 2. Current on forward (F) (a) or reverse (R) (b) from forward/reverse lever (12) flows to neutral relay (13) (coil side) and excites neutral relay (13). 3. Current which flows to terminal K15 of ECM (10) through neutral relay (13) (contact side) from terminal K68 of ECM (10) stops flowing. 4. ECM(10) disconnects terminal K73 from the ground circuit and disconnects starter relay 1 (6) from the ground circuit. 5. Starter relay 1 (6) is turned OFF. As current from starter relay 1 (6) stops flowing to starter motor (7), starter motor (7) does not rotate.

T2-3-12

SECTION 2 SYSTEM Group 3 ECM System

K73 K28 K35

2 3

K68

K15

7 6

11 12

a b

TNCC-02-03-005 1234-

Key Switch START Position Battery Battery Relay

5678-

Fusible Link A Starter Relay 1 Starter Motor Fusible Link (100A)

Current on Forward (F)

Current on Reverse (R)

9101112-

T2-3-13

Fuse Box A ECM MC Forward/Reverse Lever

13- Neutral Relay

SECTION 2 SYSTEM Group 3 ECM System Engine Trouble Alarm Control Operation: 1. ECM (14) detects the trouble due to the signals from sensors (1 to 5, 9), supply pump (11), the injector, and EGR motor (6) and sends fault code (18) of ECM (14) to monitor controller (19) and ICF (16) by using CAN communication (15). 2. At the same time, monitor controller (19) receives service signal (17) from ECM (14). 3. Monitor controller (19) lights the service indicator as well as the engine warning indicator of monitor panel. 4. ICF (16) records a chronology of fault codes (18) of ECM (14) and sends them to center server by using Communication terminal.

T2-3-14

SECTION 2 SYSTEM Group 3 ECM System

1 2 3

5 6 15 14 7

16 9

13 10 17 11 18

TNCC-02-03-006

12356-

Crank Speed Sensor Cam Angle Sensor Coolant Temperature Sensor EGR Motor Position Sensor EGR Motor

79101112-

Two-Way Valve Common Rail Pressure Sensor Common Rail Supply Pump Fuel Tank

1314151617-

T2-3-15

Suction Control Valve ECM CAN Communication ICF Service Signal

18- ECM Fault Code 19- Monitor Controller

SECTION 2 SYSTEM Group 3 ECM System Engine Oil Pressure Alarm Control Operation: 1. Engine oil pressure sensor (1) sends signals to ECM (2) when engine oil pressure decreases. 2. ECM (2) sends signals (3, 4) to monitor controller (5). 3. Monitor controller (5) lights the engine warning indicator as well as the engine oil pressure indicator of monitor panel.

3 4

5 TNCC-02-03-007

12-

Engine Oil Pressure Sensor ECM

34-

Engine Trouble Alarm Signal Engine Oil Pressure Signal

T2-3-16

Monitor Controller

SECTION 2 SYSTEM Group 3 ECM System Overheat Alarm Control Operation: 1. Coolant temperature sensor (1) sends the coolant overheat signal to ECM (2). 2. ECM (2) sends signals (3, 4) to monitor controller (5). 3. Monitor controller (5) lights the engine warning indicator as well as the overheat indicator of monitor panel.

3 4

5 TNCC-02-03-008

12-

Coolant Temperature Sensor ECM

34-

Engine Trouble Alarm Signal Overheat Signal

T2-3-17

Monitor Controller

SECTION 2 SYSTEM Group 3 ECM System (Blank)

T2-3-18

SECTION 2 SYSTEM Group 4 Hydraulic System Outline Hydraulic system is broadly divided into the main circuit, HST circuit, transmission circuit, and pilot circuit. Main Circuit Power Source Main Pump Secondary Steering Pump (Option)

HST Circuit Power Source HST Pump (HST Charging Pump)

Transmission Circuit Power Source Brake/ Transmission Pump

Controller Control Valve Priority Valve Steering Valve

Supplied to Lift Arm Cylinder, Bucket Cylinder, Steering Cylinder

Controller Forward/Reverse Control Solenoid Valve

Supplied to HST Motor

Controller Supplied to Driving Mode Selection Solenoid Valve Brake Circuit Driving Mode Selection Valve Clutch Circuit Parking Brake Solenoid Valve

Pilot Circuit (Only Hydraulic Operated Type) (Option) Power Source Controller HST Charging Pump Pilot Valve

Supplied to Operation Control Circuit

T2-4-1

SECTION 2 SYSTEM Group 4 Hydraulic System Main Circuit Outline: 1. Main pump (1) draws hydraulic oil from hydraulic oil tank (13) through suction filter (14) and delivers it to priority valve (2). 2. Priority valve (2) shifts the priority spool according to the steering operation. (Refer to Priority Valve Circuit (When steering is in neutral).) 3. Pressurized oil from main pump (1) is supplied to steering valve (11) and control valve (3) by shifting the priority spool. 4. Pressurized oil in steering valve (11) moves steering cylinders (10) at right and left by shifting the steering spool. (Refer to Steering Circuit.) 5. Returning oil from steering cylinders (10) returns to hydraulic oil tank (13) through steering valve (11). 6. Pressurized oil in control valve (3) moves lift arm cylinder (8) and bucket cylinder (7) by shifting lift arm spool (5) and bucket spool (4). (Refer to Lift Arm, Bucket Circuit.) 7. Returning oil from bucket cylinder (7) and lift arm cylinder (8) returns to hydraulic oil tank (13) through control valve (3).

T2-4-2

SECTION 2 SYSTEM Group 4 Hydraulic System

6 3 11

5 4

TNCC-02-04-007

1234-

Main Pump Priority Valve Control Valve Bucket Spool

5678-

Lift Arm Spool Attachment Spool (Option) Bucket Cylinder Lift Arm Cylinder

9101112-

T2-4-3

Attachment Cylinder (Option) Steering Cylinder Steering Valve Return Filter

13- Hydraulic Oil Tank 14- Suction Filter

SECTION 2 SYSTEM Group 4 Hydraulic System Steering Circuit

NOTE: Refer to COMPONENT OPERATION/Steering Valve. y Priority Valve Circuit

y Relief Circuit

1. Priority spool (2) of priority valve (7) is shifted according to the steering wheel (14) operation and its speed.

Main relief valve (priority valve) (18) prevents the pressure in the circuit (between pump and steering valve) from increasing over the set pressure while operating steering spool (13).

2. Pressurized oil from port CF of priority valve (7) is supplied to steering valve (5). (Refer to Priority Valve Circuit (When steering is in neutral).)

y Steering Circuit 1. When steering wheel (14) is operated, pressurized oil from port CF of priority valve (7) flows to steering spool (13) through load check valve (17) of steering valve (5) and rotates gerotor (12). 2. The delivered pressurized oil due to gerotor (12) rotation moves steering cylinder (6). 3. Orifice 4 (15) is opened or closed according to pressurized oil flow rate so that pressurized oil flow rate which is supplied to gerotor (12) is changed. 4. Load check valve (17) prevents pressurized oil which is supplied to steering spool (13) from flowing reversely.

T2-4-4

SECTION 2 SYSTEM Group 4 Hydraulic System

5 12

13 14

P 15

10 8

9 LS

CF EF

3 LS1 LS2 10

11 1

12345-

Main Pump Priority Spool Orifice 1 Control Valve Steering Valve

678910-

Steering Cylinder Priority Valve Orifice 3 Orifice 2 Spring

1112131415-

T2-4-5

Hydraulic Oil Tank Gerotor Steering Spool Steering Wheel Orifice 4

TNCC-02-04-008

16- Check Valve 17- Load Check Valve 18- Main Relief Valve (Priority Valve)

SECTION 2 SYSTEM Group 4 Hydraulic System Priority Valve Circuit (When steering is in neutral)

NOTE: Orifice 2 (9) of priority valve (7) is installed in

1. When the engine is stopped, priority spool (2) of priority valve (7) has been pushed to the right by the spring (10) force. 2. When the engine is started, pressurized oil delivered from main pump (1) flows to steering valve (5) through priority spool (2) of priority valve (7). 3. At the same time, it also flows to ports LS1 and LS2 through orifices 1 (3) and 2 (9) respectively. 4. When the steering is in neutral, pressurized oil which has flown to port LS2 flows to the hydraulic oil tank (11) through orifice 3 (8) and steering spool (12) of steering valve (5). Therefore, port LS2 is not pressurized. 5. As pressure at port LS1 is larger than the spring (10) force, priority spool (2) of priority valve (7) is moved to the left. 6. More pressurized oil in main pump (1) flows to control valve (4). 7. Priority spool (2) of priority valve (7) has a notch to lead pressurized oil from main pump (1) to port CF (toward steering valve (5)) and a notch to lead pressurized oil to port EF (toward control valve (4)). Both notches are constantly connected to the delivery port in main pump (1). 8. Priority spool (2) of priority valve (7) is moved to the left until pressure of port LS1 is balanced with the spring (10) force. At this time. the opening of port CF becomes minimum.

T2-4-6

order to warm up the circuit by leading pressurized oil to hydraulic oil tank (11) from port LS2 with steering valve (5) set in neutral. Although the diameter of orifice 2 (9) is small and temperature of pressurized oil passing through it rises rapidly, pressure is not raised enough to influence the movement of priority spool (2) of priority valve (7).

SECTION 2 SYSTEM Group 4 Hydraulic System

P 4 8

9 LS

CF EF 3 LS1

LS2 10

When Engine Stops T4FJ-02-03-002

NOTE: The illustration shows the oil flow without operation while the engine is running.

123-

Main Pump Priority Spool Orifice 1

456-

Control Valve Steering Valve Steering Cylinder

789-

T2-4-7

Priority Valve Orifice 3 Orifice 2

10- Spring 11- Hydraulic Oil Tank 12- Steering Spool

SECTION 2 SYSTEM Group 4 Hydraulic System Steering Circuit (When steering is operated) 1. When steering wheel (10) is operated, the oil passage (orifice 4 (11)) between steering spool (5) and sleeve (4) of steering valve (7) is opened in proportion to the steering wheel (10) rotation speed. Port P is connected to gerotor (9) in steering valve (7).

6. At this time, pressurized oil from main pump (1) flows to both steering valve (7) and control valve (3). 7. Pressurized oil from main pump (1) flows to greater (9) through steering spool (5) and sleeve (4) in steering valve (7).

2. When steering wheel (10) is operated quickly, the opening of orifice 4 (11) becomes large and pressurized oil flow rate flowing to steering valve (7) increases. On the contrary, when steering wheel (10) is operated slowly, the opening of orifice 4 (11) becomes small and pressurized oil flow rate flowing to steering valve (7) decreases.

8. Gerotor (9) delivers pressurized oil as a hydraulic motor. This pressurized oil flows to steering cylinders (8) and the machine turns. 9. When the rotation of steering wheel (10) is stopped, the oil passage between steering spool (5) and sleeve (4) is closed. Steering spool (5) and sleeve (4) are returned to the neutral position completely by the spring (6) force. Pressurized oil from main pump (1) does not flow to gerotor (9) and steering cylinders (8) are stopped. (Refer to COMPONENT OPERATION / Control Valve.)

3. Orifice 4 (11) is opened at the same time when steering wheel (10) is operated, pressurized oil between port LS and port CF in priority valve (12) and orifice 4 (11) in steering valve (7) flows to gerotor (9).

NOTE: The load sensing control is performed by the

4. As pressurized oil flows to gerotor (9), the pressure between LS and port CF in priority valve (12) and orifice 4 (11) in steering valve (7) decreases and priority spool (2) of priority valve (12) is moved to the right.

combinations of orifice 4 (11) and priority spool (2) of priority valve (12). Priority spool (2) of priority valve (12) corresponds to the flow rate control valve.

NOTE: As gerotor (9) is connected to the middle shaft of

5. Priority spool (2) of priority valve (12) is moved to the position where pressurized oil corresponding to the opening of orifice 4 (11) flows to steering valve (7).

T2-4-8

steering valve (7), powered steering effect is generated. (Refer to COMPONENT OPERATION/Steering Valve.)

SECTION 2 SYSTEM Group 4 Hydraulic System

9 4 6 10

5 4

P 11

LS1 13

14 1

T4FJ-02-03-003

NOTE: The illustration shows the oil flow when steering wheel (11) is rotated right.

1234-

Main Pump Priority Spool Control Valve Sleeve

5678-

Steering Spool Spring Steering Valve Steering Cylinder

9101112-

T2-4-9

Gerotor Steering Wheel Orifice 4 Priority Valve

13- Spring 14- Hydraulic Oil Tank

SECTION 2 SYSTEM Group 4 Hydraulic System Steering Stop Circuit (When steering cylinder is at stroke end) 1. Pressurized oil which flows from port P in steering valve (4) to greater (6) is divided in steering spool (14) and is routed to port LS2 through port LS and orifice 3 (8) in priority valve (10). 2. When steering cylinder (5) reaches the stroke end, the pressure at port LS 2 in priority valve (10) also increases due to pressurized oil flowing from main pump (1) through port LS. 3. When the pressure at port LS2 exceeds the specified level, relief valve (12) in priority valve (10) is operated and pressurized oil routed to port LS2 flows from relief valve (12) to hydraulic oil tank (13). 4. Therefore, the pressure difference between port LS1 and port LS2 occurs due to orifice 2 (9). 5. Therefore, priority spool (2) in priority valve (10) is moved to the left and pressurized oil from main pump (1) flows to control valve (3).

T2-4-10

SECTION 2 SYSTEM Group 4 Hydraulic System

4 6

P 14

3 8

9 LS

LS1 12

LS2 11

13 1

T4FJ-02-03-004

NOTE: The illustration shows the oil flow when relief valve (12) in priority valve (10) is operated.

1234-

Main Pump Priority Spool Control Valve Steering Valve

5678-

Steering Cylinder Gerotor Steering Wheel Orifice 3

9101112-

T2-4-11

Orifice 2 Priority Valve Spring Relief Valve

13- Hydraulic Oil Tank 14- Steering Spool

SECTION 2 SYSTEM Group 4 Hydraulic System Secondary Steering Circuit (Option) 1. When the conditions for secondary steering control exist, the monitor controller activates secondary steering motor (3) so that secondary steering pump (4) is activated. (Refer to Control System.) 2. Secondary steering pump (4) draws hydraulic oil from hydraulic oil tank (10) and delivers it to steering valve (12) through load check valve (6) and secondary steering block (7). 3. Steering valve (12) moves steering cylinder (14) by shifting steering spool (13) when operating steering wheel (11). (Refer to Steering Circuit.) 4. Load check valve (6) is installed so that pressurized oil from priority valve (2) may not be routed to secondary steering pump (4) in normal state. 5. Load check valve (8) is installed so that pressurized oil from secondary steering pump (4) may not flow back to the main pump (1) side. 6. Relief valve (5) prevents the pressure in the circuit between secondary steering pump (4) and steering valve (12) from increasing over the set pressure when secondary steering pump (4) is operated.

T2-4-12

SECTION 2 SYSTEM Group 4 Hydraulic System

5 3

TNCC-02-04-012

12345-

Main Pump Priority Valve Secondary Steering Motor Secondary Steering Pump Relief Valve

678910-

Load Check Valve Secondary Steering Block Load Check Valve Steering Pressure Switch Hydraulic Oil Tank

11121314-

T2-4-13

Steering Wheel Steering Valve Steering Spool Steering Cylinder

SECTION 2 SYSTEM Group 4 Hydraulic System Lift Arm, Bucket Circuit

NOTE: Manually operated type control valve circuit is explained here. Neutral Circuit

Relief Circuit

1. Pressurized oil (EF) from the priority valve is supplied to control valve (1). (Refer to Priority Valve Circuit (When steering is in neutral).)

1. Main relief valve (2) prevents the pressure in the circuit from increasing over the set pressure while operating each spool of lift arm spool (6) and bucket spool (3).

2. When not operating the front attachment control lever (when lift arm spool (6) and bucket spool (3) are in the neutral position), pressurized oil (EF) in control valve (1) flows back to hydraulic oil tank (15) through neutral circuit (5).

2. When bucket spool (3) is in the neutral position, overload relief valve (bucket) (13) prevents the pressure in the circuit (between control valve and actuator) due to surge pressure developed by external force from increasing over the set pressure. 3. In addition, overload relief valve (bucket: rod side) (13) is equipped with make-up function. It draws pressurized oil from hydraulic oil tank (15) and prevents cavitation from occurring when the pressure in the circuit (between control valve and actuator) decreases below the specified value.

Single Operation Circuit 1. During single operation of lift arm or bucket, pressurized oil (EF) in control valve (1) flows to lift arm spool (6) and bucket spool (3) through load check valves (12, 14), and moves lift arm cylinder (7) and bucket cylinder (4).

NOTE: Overload relief valves are also equipped to the lift arm rod side and the bottom side circuits of the hydraulic operated control valve (option) (Refer to COMPONENT OPERATION/Control Valve)

2. Load check valves (12, 14) prevent pressurized oil which has been supplied to lift arm spool (6) and bucket spool (3) from flowing reversely.

T2-4-14

SECTION 2 SYSTEM Group 4 Hydraulic System

10 9

8 11 7 6

13 5 12 3

2 4

1 EF

15 TNCC-02-04-011

EF- From Priority Valve (Main Pump Pressurized Oil) 123456-

Control Valve Main Relief Valve Bucket Spool Bucket Cylinder Neutral Circuit Lift Arm Spool

789101112-

Lift Arm Cylinder Attachment Spool (Option) Attachment Cylinder (Option) Overload Relief Valve (Option) Load Check Valve (Option) Load Check Valve (Lift Arm)

13- Overload Relief Valve (Bucket: Rod Side) 14- Load Check Valve (Bucket) 15- Hydraulic Oil Tank

T2-4-15

SECTION 2 SYSTEM Group 4 Hydraulic System Single Operation Circuit y Bucket Rollback Single Operation

NOTE: The bucket rollback operation when not operating the steering is explained here. 1. Bucket spool (6) is shifted when the front attachment control lever is set to bucket rollback (back tilting) operation. 2. When not operating the steering wheel, more pressurized oil (EF) from the priority valve is supplied to control valve (1). (Refer to Priority Valve Circuit (When steering is in neutral).) 3. Pressurized oil (EF) from the priority valve flows to bucket spool (3) through load check valve (14). 4. Pressurized oil (EF) flowing to bucket spool (3) moves bucket cylinder (4) and rolls the bucket back. 5. Returning oil from bucket cylinder (4) returns to hydraulic oil tank (15) through bucket spool (3).

T2-4-16

SECTION 2 SYSTEM Group 4 Hydraulic System

10 9

8 11 7 6

13 5 12 3

2 4

1 EF

15 TNCC-02-04-010

EF- From Priority Valve (Main Pump Pressurized Oil) 123456-

Control Valve Main Relief Valve Bucket Spool Bucket Cylinder Neutral Circuit Lift Arm Spool

789101112-

Lift Arm Cylinder Attachment Spool (Option) Attachment Cylinder (Option) Overload Relief Valve (Option) Load Check Valve (Option) Load Check Valve (Lift Arm)

13- Overload Relief Valve (Bucket: Rod Side) 14- Load Check Valve (Bucket) 15- Hydraulic Oil Tank

T2-4-17

SECTION 2 SYSTEM Group 4 Hydraulic System Combined Operation Circuit y Combined operation of lift arm raise and bucket dump:

NOTE: The lift arm raise and bucket dump operation when not operating the steering is explained here. 1. Lift arm spool (6) and bucket spool (3) are shifted when the front attachment control lever is set to lift arm raise and bucket dump (frontward tilting) operation. 2. When not operating the steering wheel, more pressurized oil (EF) from the priority valve is supplied to control valve (1). (Refer to Priority Valve Circuit (When steering is in neutral).) 3. Pressurized oil (EF) is divided in control valve (1). One flows to bucket spool (3) through load check valve (14). 4. Pressurized oil (EF) flowing to bucket spool (3) moves bucket cylinder (14) and tilts the bucket forward. 5. The other of pressurized oil (EF) flows through parallel circuit (16), and load check valve (12), and flows to lift arm spool (6). 6. Pressurized oil (EF) flowing to lift arm spool (6) moves lift arm cylinder (7) and raises the lift arm. 7. Returning oil from lift arm cylinder (7) and bucket cylinder (4) return to hydraulic oil tank (15) through lift arm spool (6) and bucket spool (3).

T2-4-18

SECTION 2 SYSTEM Group 4 Hydraulic System

10 9

8 11 7 6

5 12 3

2 16

1 EF

15 TNCC-02-04-009

EF- From Priority Valve (Main Pump Pressurized Oil) 123456-

Control Valve Main Relief Valve Bucket Spool Bucket Cylinder Neutral Circuit Lift Arm Spool

789101112-

Lift Arm Cylinder Attachment Spool (Option) Attachment Cylinder (Option) Overload Relief Valve (Option) Load Check Valve (Option) Load Check Valve (Lift Arm)

13- Overload Relief Valve (Bucket: Rod Side) 14- Load Check Valve (Bucket) 15- Hydraulic Oil Tank 16- Parallel Circuit

T2-4-19

SECTION 2 SYSTEM Group 4 Hydraulic System y Combined operation of steering and lift arm raise:

NOTE: The lift arm raise operation when turning the steering wheel (right) is explained here. 1. When steering wheel (4) is rotated right, pressurized oil (CF) from priority valve (3) is supplied to steering valve (5). At the same time, other pressurized oil is supplied to control valve (9) from port EF. (Refer to Priority Valve Circuit (When steering is in neutral).) 2. Pressurized oil from port CF in priority valve (3) flows to steering spool (7) through load check valve (8) in steering valve (5). 3. Pressurized oil flowing to steering spool (7) moves steering cylinders (6) and the machine turns right. (Refer to Steering Circuit.) 4. Lift arm spool (13) in control valve (9) is shifted when the front attachment control lever is set to lift arm raise operation. 5. Pressurized oil port EF in priority valve (3) flows to lift arm spool (13) through load check valve (14) in control valve (9). 6. Pressurized oil flowing to lift arm spool (13) moves lift arm cylinders (11) and raises the lift arm. 7. Therefore, steering (right) operation and lift arm raise operation are simultaneously made.

T2-4-20

SECTION 2 SYSTEM Group 4 Hydraulic System

6 9 10

11 12

15 7

16 P2

8 2 3

2 LS

1 2 TNCC-02-04-014

12345-

Main Pump Hydraulic Oil Tank Priority Valve Steering Wheel Steering Valve

678910-

Steering Cylinder Steering Spool Load Check Valve Control Valve Attachment (Option)

1112131415-

T2-4-21

Lift Arm Cylinder Attachment Spool (Option) Lift Arm Spool Load Check Valve Bucket Cylinder

16- Bucket Spool

SECTION 2 SYSTEM Group 4 Hydraulic System HST Circuit Outline 1. HST (Hydro-Static Transmission) circuit is a closed circuit including HST pump (1) and HST motor (5). 2. HST pump (1) is directly activated by the power of engine (3). HST motor (5) is turned by pressurized oil from HST pump (1). 3. The output power of HST motor(5) is transmitted to transmission (6), propeller shaft (8), front axle (9), rear axle (10), and tires in sequence. 4. HST pump (1) has built-in HST charging pump (2). HST charging pump (2) is directly driven by the engine (3) power and draws hydraulic oil from hydraulic oil tank (7). Hydraulic oil is added to the low-pressure side in the closed circuit in HST pump (1) and HST motor (5) through HST filter (4). 5. Pressurized oil from HST charging pump (2) also cools HST pump (1) and HST motor (5). In addition, pressurized oil from HST charging pump (2) is the oil pressure source of HST pump (1) displacement angle control.

T2-4-22

SECTION 2 SYSTEM Group 4 Hydraulic System

1 3 2

7 5

8 T4FJ-02-03-014

123-

HST Pump HST Charging Pump Engine

456-

HST Filter HST Motor Transmission

789-

T2-4-23

Hydraulic Oil Tank Propeller Shaft Front Axle

10- Rear Axle

SECTION 2 SYSTEM Group 4 Hydraulic System Charge Circuit

Neutral Circuit

1. Pressurized oil from HST charging pump (5) flows to orifice (6) in DA valve (4) through HST filter (3).

1. Forward/reverse control solenoid valve (2) is located between DA valve (4) and displacement angle control cylinder (9). When the forward/reverse lever is in the neutral position, forward/reverse control solenoid valve (2) is not excited and is kept in the neutral position.

2. The pressure difference occurs between the front and the rear of orifice (6) due to the delivery flow rate of HST charging pump (5). DA valve (4) decreases oil pressure in HST charging pump (5) according to this pressure difference.

2. Therefore, the decreased pressurized oil in DA valve (4) is not supplied to displacement angle control cylinder (9) and the HST pump (1) displacement angle is kept in the neutral position.

3. DA valve (4) controls the HST pump (1) displacement angle by supplying the decreased pressurized oil to displacement angle control cylinder (9).

3. Therefore, pressurized oil is not delivered from HST pump (1) and HST motor (10) does not turn.

4. In addition, pressurized oil flowing through orifice (6) also flows to high-pressure relief valve (7). 5. High-pressure relief valve (7) provides the function of a check valve. When the flow rate on the lowpressure side in the HST close circuit is insufficient, the check valve is opened and pressurized oil from HST charging pump (5) is added.

NOTE: The pump delivery flow rate of HST charging pump (5) is proportional to the engine (8) speed. Therefore, the displacement angle control pressure of HST pump (1) is almost proportional to the engine (8) speed.

T2-4-24

SECTION 2 SYSTEM Group 4 Hydraulic System

2 1 4

8 7 6 11 12

T4FJ-02-03-005 1234-

HST Pump Forward/Reverse Control Solenoid Valve HST Filter DA Valve

5678-

HST Charging Pump Orifice High-Pressure Relief Valve Engine

Displacement Angle Control Cylinder 10- HST Motor 11- Travel Control Solenoid Valve 12- Transmission

T2-4-25

SECTION 2 SYSTEM Group 4 Hydraulic System Forward Circuit 1. When the forward/reverse lever is set to the forward position, the forward side solenoid valve of forward/ reverse control solenoid valve (2) is activated and the spool moves to the left. 2. Therefore, the circuit between DA valve (3) and displacement angle control cylinder (5) is connected, and pressurized oil from HST charging pump (4) is supplied to displacement angle control cylinder (5). 3. As pressurized oil from HST charging pump (4) is supplied to displacement angle control cylinder (5) at the right, the piston of displacement angle control cylinder (5) moves to the left. 4. Therefore, the HST pump (1) displacement angle is changed from the neutral position and HST pump (1) delivers pressurized oil. 5. Pressurized oil from HST pump (1) is supplied to HST motor (6). 6. Therefore, HST motor (6) rotates to the forward direction.

NOTE: When the forward/reverse lever is in the forward position, travel control solenoid valve (7) is not activated.

T2-4-26

SECTION 2 SYSTEM Group 4 Hydraulic System

2 3

7 8 6

TNCC-02-04-002

123-

HST Pump Forward/Reverse Control Solenoid Valve DA Valve

456-

HST Charging Pump Displacement Angle Control Cylinder HST Motor

78-

T2-4-27

Travel Control Solenoid Valve Transmission

SECTION 2 SYSTEM Group 4 Hydraulic System Reverse Circuit 1. When the forward/reverse lever is set to the reverse position, the reverse side solenoid valve of forward/ reverse control solenoid valve (2) is activated and the spool moves to the right. 2. As pressurized oil from HST charging pump (4) is supplied to displacement angle control cylinder (5) at the left, the displacement angle direction of HST pump (1) is reversed in a forward circuit case. 3. Therefore, HST motor (6) rotates to the reverse direction.

NOTE: When the forward/reverse lever is in the reverse position, travel control solenoid valve (7) is activated.

T2-4-28

SECTION 2 SYSTEM Group 4 Hydraulic System

2 3

7 8 6

TNCC-02-04-001

123-

HST Pump Forward/Reverse Control Solenoid Valve DA Valve

456-

HST Charging Pump Displacement Angle Control Cylinder HST Motor

78-

T2-4-29

Travel Control Solenoid Valve Transmission

SECTION 2 SYSTEM Group 4 Hydraulic System Inching Circuit 1. When depressing brake pedal (7), declutch valve (6) is activated and pressurized oil from DA valve (3) flows to hydraulic oil tank (5). 2. Therefore, the displacement angle control pressure of HST pump (1) decreases and displacement angle control cylinder (4) returns to the neutral position. 3. Consequently, the displacement angle of HST pump (1) is changed to the neutral position and the delivery flow rate of HST pump (1) decreases. 4. As the delivery flow rate HST pump (1) decreases, the rotation speed of the HST motor decreases and the machine speed is decelerated. 5. The displacement angle control pressure of HST pump (1) is changed according to the depressing amount of brake pedal (7). When brake pedal (7) is depressed fully, the displacement angle of HST pump (1) is in the neutral position.

T2-4-30

SECTION 2 SYSTEM Group 4 Hydraulic System

3 1 8

4 9 10 T4FJ-02-03-013

NOTE: The illustration shows the oil flow while driving in forward direction. 12-

HST Pump Forward/Reverse Control Solenoid Valve

34-

DA Valve Displacement Angle Control Cylinder

567-

T2-4-31

Hydraulic Oil Tank Declutch Valve Brake Pedal

8- To HST Motor (Port A) 9- From HST Motor (Port B) 10- From Hydraulic Oil Tank

SECTION 2 SYSTEM Group 4 Hydraulic System (Blank)

T2-4-32

SECTION 2 SYSTEM Group 4 Hydraulic System Transmission Circuit Outline of Clutch Circuit 1. Brake/ transmission pump (1) draws pressurized oil in transmission (7) from oil pan (8) through the suction filter and delivers it. 2. The delivered pressurized oil flows to brake valve (3) through transmission oil filter (2). 3. Pressurized oil which has flown to brake valve (3) flows to clutch (5) when clutch (5) is connected, and returns to oil pan (8) when clutch (5) is disconnected. 4. In addition, pressurized oil which has flown to brake valve (3) is used for lubrication of transmission (7), and returns to oil pan (8) through each part of transmission (7). 6

5 4

T4FJ-02-03-013

123-

Brake/Transmission Pump Transmission Oil Filter Brake Valve

456-

HST Motor Clutch Lubrication Circuit

78-

T2-4-33

Transmission Oil Pan

SECTION 2 SYSTEM Group 4 Hydraulic System Travel Slow Mode Selector Circuit

Travel Fast Mode Selector Circuit

1. Pressurized oil from brake/transmission pump (1) flows to brake valve (5) through the transmission oil filter. Relief valve (8) is installed to brake valve (5) and the circuit pressure is kept constant.

1. While clutch (17) is connected to the slow mode, driving mode selection solenoid valve (13) of transmission (16) is kept activated by current from MC. Therefore, the spool is in the left.

2. When the shift switch is shifted to the slow mode, current flows to travel mode selector solenoid valve (13) from MC.

2. Pressurized oil is routed to driving mode selection valve (15) and the spool is in the left.

3. Driving mode selection solenoid valve (13) is activated, moves the spool to the left, and supplies pressurized oil to driving mode selection valve (15). 4. Therefore, the spool of driving mode selection valve (15) is moved to the left and pressurized oil is routed to the slow speed side of clutch (17) so that the clutch (17) pressure increases. 5. Consequently, clutch (17) is connected to the slow mode. 6. While clutch (17) is connected to the slow mode, current continues to flow to driving mode selection solenoid valve (13) from MC.

3. When the shift switch is shifted to the fast mode, current stops flowing to driving mode selection solenoid valve (13) from MC. Therefore, the spool in driving mode selection solenoid valve (13) is moved to the right and the oil passage is connected to oil pan (14). 4. Therefore, the spool in driving mode selection valve (15) is moved to the right and pressurized oil from brake/transmission pump (1) is routed to the fast speed side of clutch (17). 5. Consequently, clutch (17) is connected to the fast mode.

Transmission Lubrication Circuit 1. Relief valve (12) allows the unused oil of transmission (16) for shifting clutch (17) to flow to each part of transmission (16) for lubrication. 2. The used oil of transmission (16) for lubrication flows to each part of transmission (16) and returns to oil pan (14).

T2-4-34

SECTION 2 SYSTEM Group 4 Hydraulic System

4 5

3 8 2

6 9 7

T4FJ-02-03-010

12345-

Brake/Transmission Pump Master Cylinder Booster Brake Oil Reserve Tank Brake Valve

678910-

Brake Pedal Orifice Relief Valve Service Brake (Front) Service Brake (Rear)

11- Lubrication Circuit 12- Relief Valve 13- Driving Mode Selection Solenoid Valve 14- Oil Pan

T2-4-35

15- Driving Mode Selection Valve 16- Transmission 17- Clutch

SECTION 2 SYSTEM Group 4 Hydraulic System (Blank)

T2-4-36

SECTION 2 SYSTEM Group 4 Hydraulic System Outline of Brake Circuit 1. Brake/transmission pump (1) draws oil in transmission (6) from oil pan (9) through the suction filter and delivers it. 2. The delivered pressurized oil flows to brake valve (3) through transmission oil filter (2). 3. Pressurized oil which has flown to brake valve (3) is routed as assist pressure to push the booster in brake valve (3) when service brake (5) is applied so that the brake pedal stepping force is reduced. 4. In addition, pressurized oil which has flown to brake valve (3) is routed to the piston in parking brake (7) built in transmission (6) and releases parking brake (7).

5 6

3 7

8 10

T4FJ-02-03-011

1234-

Brake/Transmission Pump Transmission Oil Filter Brake Valve Brake Oil Reserve Tank

5678-

Service Brake Transmission Parking Brake Clutch

9- Oil Pan 10- HST Motor

T2-4-37

SECTION 2 SYSTEM Group 4 Hydraulic System Service Brake Circuit The service brake circuit operates service brake (front (9), rear (10)) in front and rear axles by brake pedal (service brake pedal) (6). 1. Pressurized oil from brake/transmission pump (1) flows to brake valve (5) through the transmission oil filter. 2. When brake pedal (service brake pedal) (6) is depressed, booster (3) of brake valve (5) is shifted. 3. At the same time, when orifice (8) of booster (3) regulates pressurized oil flowing to booster (3) from brake/transmission pump (1), pressurized oil from brake/transmission pump (1) pushes booster (3) as assist pressure. The brake pedal (6) stepping force is reduced due to this assist pressure (7). 4. Master cylinder (2) and booster (3) are shifted together and pressurized oil between master cylinder (2) and service brakes (front (9), rear (10)) in creases. Service brake (front) (9) and service brake (rear) (10) of both front and rear axles are applied by the increased oil pressure so that the machine speed is decelerated.

T2-4-38

SECTION 2 SYSTEM Group 4 Hydraulic System

4 5

6 8

10 11

T4FJ-02-03-007

12345-

Brake/Transmission Pump Master Cylinder Booster Brake Oil Reserve Tank Brake Valve

6789-

Brake Pedal (Service Brake Pedal) Assist Pressure Orifice Service Brake (Front)

10111213-

T2-4-39

Service Brake (Rear) Transmission Parking Brake Parking Brake Solenoid Valve

SECTION 2 SYSTEM Group 4 Hydraulic System Parking Brake Circuit

NOTE: When parking brake solenoid valve (13) is ON, parking brake (12) is released. When parking brake solenoid valve (13) is OFF, parking brake (12) is applied. (Refer to Electrical System.) y Circuit with parking brake (12) released: 1. Pressurized oil from brake/transmission pump (1) is routed to parking brake solenoid valve (13). 2. When the parking brake switch is turned OFF (release), parking brake solenoid valve (13) is turned ON and the spool of parking brake solenoid valve (13) is moved. 3. Pressurized oil from brake/transmission pump (1) compresses the spring of parking brake (12) in transmission (11) through parking brake solenoid valve (13) so that parking brake (12) is released.

T2-4-40

SECTION 2 SYSTEM Group 4 Hydraulic System

4 5

6 8

10 11

T4FJ-02-03-008

1234-

Brake/Transmission Pump Master Cylinder Booster Brake Oil Reserve Tank

5678-

Brake Valve Brake Pedal Assist Pressure Orifice

9101112-

T2-4-41

Service Brake (Front) Service Brake (Rear) Transmission Parking Brake

13- Parking Brake Solenoid Valve

SECTION 2 SYSTEM Group 4 Hydraulic System Ride Control Circuit (Option)

NOTE: Refer to SYSTEM/ Control System. 1. During front attachment operation, the operating pressure of lift arm cylinder (4) is accumulated in ride control accumulator (2) through charge-cut spool (8). 2. When the ride control switch is turned ON, ride control solenoid valve (10) is activated and spool (9) is moved to the left. 3. The bottom side of lift arm cylinder (4) is connected to ride control accumulator (2). The rod side of lift arm cylinder (4) is connected to hydraulic oil tank (7). 4. The force to raise the front attachment is relieved to hydraulic oil tank (7). The force to lower the front attachment is reduced by ride control accumulator (2). Therefore, the machine moves stably when traveling on rough roads.

T2-4-42

SECTION 2 SYSTEM Group 4 Hydraulic System

5 1

6 8

TNCC-02-04-013

NOTE: The illustration shows the oil flow when ride control solenoid valve (10) is activated.

1234-

Ride Control Valve Ride Control Accumulator To Control Valve Lift Arm Cylinder

5678-

Ride Control Operating Signal From HST Charging Pump Hydraulic Oil Tank Charge-Cut Spool

9- Spool 10- Ride Control Solenoid Valve

T2-4-43

SECTION 2 SYSTEM Group 4 Hydraulic System Pilot Circuit (Only Hydraulic Operated Type) (Option) Outline: Pressurized oil from HST charging pump (12) is used in order to operate the operation control circuit.

3 1

4 16

5 6 7 8 9

13 TNCC-02-04-005

1234-

Pilot Valve (Right) (Lift Arm, Bucket) Pilot Valve (Option) Operation Control Circuit Control Valve

56789-

Spool 3 (Option) Spool 2 (Option) Spool 1 (Option) Lift Arm Spool Bucket Spool

1011121314-

T2-4-44

Hydraulic Oil Tank Suction Filter HST Charging Pump HST Charge Oil Filter Check Valve (Option)

15- Accumulator (Option) 16- Pilot Shut-Off Solenoid Valve

SECTION 2 SYSTEM Group 4 Hydraulic System Operation Control Circuit 1. The pilot valve controls pressurized oil from HST charging pump (B1) and moves the spool in control valve (B0).

A3 A2

TNCC-02-04-006

12-

Bucket Dump Bucket Rollback

A0- Bucket B0- Control Valve

34-

Lift Arm Lower Lift Arm Raise

A1- Lift Arm B1- HST Charging Pump

56-

Option 1 (Lower) Option 1 (Raise)

A2- Option 1

T2-4-45

78-

Option 2 (Lower) Option 2 (Raise)

A2- Option 2

SECTION 2 SYSTEM Group 4 Hydraulic System (Blank)

T2-4-46

SECTION 2 SYSTEM Group 5 Electrical System Outline The electrical circuit is broadly divided into the main circuit, light/horn circuit, and control circuit. y Main Circuit: Operates the engine and the battery charging related circuits. y Accessory Circuit: Operates the accessory circuit. Consists of monitor controller, relays, and switches. y Light/Horn Circuit: The circuits for headlights, work lights, turn signal lights, bake lights, and horn. y Control Circuit: Controls the engine, pump, HST motor, transmission, and circuit for valves [composed of actuator as solenoid valve, MC (main controller), ECM (engine control module), ICF (information controller), monitor controller, switch, sensor, and pressure switch]. (Refer to SYSTEM / Control System, ECM System.)

T2-5-1

SECTION 2 SYSTEM Group 5 Electrical System Main Circuit x Electric Power Circuit: Supplies electric power to the electrical system. x CAN Circuit: Performs communication between each controller. x Accessory Circuit: Is operated when the key switch is in the ACC position. x Light Bulb Check Circuit: Is the circuit to check the bulbs of monitor controller and indicators. x Preheating Circuit: Assists the engine when starting in cold weather. x Engine Starting Circuit: Starts the engine. x Charging Circuit: Supplies electric power to the batteries and charges them. x Surge Voltage Prevention Circuit: Prevents the occurrence of serge voltage developed when stopping the engine. x Engine Stop Circuit: Stops the engine by using ECM. x Pilot Shut-Off Circuit (Key Switch: ON) (Hydraulic Operated Type) (Option): Supplies pressure oil from the HST charging pump to the pilot valve through the pilot shut-off solenoid valve.

T2-5-2

SECTION 2 SYSTEM Group 5 Electrical System (Blank)

T2-5-3

SECTION 2 SYSTEM Group 5 Electrical System Electric Power Circuit (Key Switch: OFF) The battery (2) minus terminal is grounded to the body. Current from the battery (1) plus terminal flows as shown below when key switch (1) is in the OFF position. Battery (2)

Fusible Link A (4)

Key Switch (1) Terminal B Fuse Box A(5) Terminal Fuel Pump Relay (Power) (6) #4 Terminal Horn Relay (Power) (7) #5 Terminal Flasher (Power) (8) #6 Hazard Light Switch (9) Terminal Load Dump Relay (Power) (22) #7 Communication Terminal (Power) (10) ICF (C1) (Power) (11) ICF (C2) (Power) (12) Option (13) Monitor Controller (Backup Power) (14) Terminal ECM (Power) (21) #8 Terminal Light Switch (15) #17 Terminal Option 1 (16) #18 Fuse Box B (17) Terminal Radio (Power) (18) #11 Cab Light (Power) (19) Tachograph (Power) (20)

T2-5-4

SECTION 2 SYSTEM Group 5 Electrical System

1 21 2

5 3 22

6 7

8 9

4 10 11 12 13 14 15 16 17

18 19 20

TNCB-02-05-002 123456-

Key Switch Battery Battery Relay Fusible Link A Fuse Box A Fuel Pump Relay (Power)

78910-

Horn Relay (Power) Flasher (Power) Hazard Light Switch Communication Terminal (Power) 11- ICF (C1) (Power)

12- ICF (C2) (Power) 13- Option 14- Monitor Controller (Backup Power) 15- Light Switch 16- Option

T2-5-5

171819202122-

Fuse Box B Radio (Power) Cab Light (Power) Tachograph (Power) ECM (Power) Load Dump Relay (Power)

SECTION 2 SYSTEM Group 5 Electrical System CAN Circuit CAN (Controller Area Network) is ISO Standards of the serial communication protocol. The network (CAN bus (4)), CAN 1 (1) is equipped for this machine. CAN bus (4) consists of two harnesses, CAN-H (High) (2) and CAN-L (Low) (3). Each controller judges the CAN bus (4) level due to potential difference between CAN-H (High) (2) and CAN-L (Low) (3). Each controller arranges the CAN bus (4) level and sends the signal and data to other controllers. In addition, termination resistors (120 Ω) (17) are installed to both ends of CAN bus (4).

T2-5-6

SECTION 2 SYSTEM Group 5 Electrical System

2 1

4 3

TDEK-02-03-004

TNCB-02-05-001

1234-

CAN1 CAN-H (High) CAN-L (Low) CAN Bus

791011-

ECM (Engine Controller) MC (Main Controller) Communication Controller ICF (Information Controller)

12131417-

T2-5-7

MPDr. Air Conditioner Controller Monitor Controller Termination Resistor (120 Ω)

SECTION 2 SYSTEM Group 5 Electrical System Accessory Circuit (Key Switch: ACC) 1. When key switch (1) is set to the ACC position, terminal B (2) is connected to terminal ACC (3) in key switch (1). 2. Current from terminal ACC (3) in key switch (1) flows as shown below and makes radio (8) operable. Key Switch Terminal ACC (3) Fuse Box B (7)

Terminal #1 Radio (8)

T2-5-8

SECTION 2 SYSTEM Group 5 Electrical System

3 4

TNCB-02-05-011 123-

Key Switch Terminal B Terminal ACC

456-

Battery Battery Relay Fusible Link A

78-

T2-5-9

Fuse Box B Radio

SECTION 2 SYSTEM Group 5 Electrical System Light Bulb Check Circuit (Key Switch: ON) 1. When key switch (1) is set to the ON position, terminal B (2) is connected to terminal M (3) in key switch (1). 2. Current from terminal M (3) in key switch (1) flows to terminal #1-2 in monitor controller (8) through fuse #13 of fuse box A (7). 3. Monitor controller (8) lights the indicators, and checks the bulbs. Then monitor controller (8) starts the liquid crystal display.

T2-5-10

SECTION 2 SYSTEM Group 5 Electrical System

3 4

7 5

6 #1-2

TNCB-02-05-003

123-

Key Switch Terminal B Terminal M

456-

Battery Battery Relay Fusible Link A

78-

T2-5-11

Fuse Box A Monitor Controller

SECTION 2 SYSTEM Group 5 Electrical System Preheating Circuit (Key Switch: ON) 1. When key switch (1) is set to the ON position, terminal B (2) is connected to terminal M (3) in key switch (1). 2. Current from terminal M (3) flows through fuse #13 of fuse box A (8) and excites battery relay (5). 3. Current from battery (4) flows to preheat relay 2 (11) (contact side) through battery relay (5) and fusible link (100 A) (7). 4. ECM (13) supplies current to preheat relay 1 (12) (coil side) from terminal A45 in ECM (13) according to the input signals from the coolant temperature sensor. 5. Therefore, preheat relay 1 (12) is excited. 6. Current from terminal M (3) flows to preheat relay 2 (11) (coil side) through fuse #14 of fuse box A (8), and preheat relay 2 (11) (contact side). Then, preheat relay 2 (11) is excited. 7. Current from preheat relay 2 (11) (contact side) flows to heater plug (10) and the preheating is carried out. 8. While preheat relay 1 (12) is excited, terminal K48 in ECM (13) is connected to the ground circuit. Current from terminal #1-21 in monitor controller (9) flows to K48 in ECM (13). Then, monitor controller (9) turns on the preheat indicator.

NOTE: Even if the preheating is not carried out, the preheat indicator lights for two seconds after the key is turned ON in order to check the indicator bulbs.

T2-5-12

SECTION 2 SYSTEM Group 5 Electrical System

A35

2 1

A45 3

13 8 4

K48

7 6

#1-21 9

10 12

TNCB-02-05-004

1234-

Key Switch Terminal B Terminal M Battery

5678-

Battery Relay Fusible Link A Fusible Link (100 A) Fuse Box A

9101112-

T2-5-13

Monitor Controller Heater Plug Preheat Relay 2 Preheat Relay 1

13- ECM

SECTION 2 SYSTEM Group 5 Electrical System Engine Starting Circuit (Key Switch: START) IMPORTANT: ECM receives the forward/reverse lever position signal from MC by using CAN communication. Forward/Reverse Lever at Neutral Position 1. When key switch (1) is set to the START position, terminal B (2) is connected to terminals M (3) and ST (4) in key switch (1). 2. Current from terminal M (3) flows through fuse #13 of fuse box A (10) and excites battery relay (6). The battery power from battery relay (6) is routed to the relay contact in starter motor (9) through starter relay 1 (8). 3. At the same time, current from fuse #14 of fuse box A (10) flow to terminal K88 in ECM (11) and the key ON signal is sent to ECM (11). 4. ECM (11) receives the forward/reverse lever neutral position signal from MC (12) by using CAN communication (13). Then, ECM (11) connects terminal K73 in ECM (11) to the ground circuit. 5. Current from terminal ST (4) flows to terminal K35 in ECM (11) and the start signal is sent. 6. Current from terminal K28 in ECM (11) flows to the coil in starter relay 1 (8) and starter relay 1 (8) is turned ON. 7. Therefore, current from starter relay 1 (8) also flows to starter motor (9). 8. Consequently, the relay in starter motor (9) is turned ON and starter motor (9) rotates.

T2-5-14

SECTION 2 SYSTEM Group 5 Electrical System

1 K73 3

K28 K35 11 K88

10 6

12 7

TNCB-02-05-005

1234-

Key Switch Terminal B Terminal M Terminal ST

5678-

Battery Battery Relay Fusible Link A Starter Relay 1

9101112-

T2-5-15

Starter Motor Fuse Box A ECM MC

13- CAN Communication

SECTION 2 SYSTEM Group 5 Electrical System Charging Circuit (Key Switch: ON) 1. After the engine starts and key switch (1) is released, key switch (1) is returned to the ON position. 2. When key switch (1) is in the ON position, terminal B (2) is connected to terminal M (3) in key switch (1). 3. Alternator (7) starts generating electricity with the engine running. Current from terminal B in alternator (7) flows to battery (4) through battery relay (5) and charges battery (4). 4. Alternator (7) disconnects the ground circuit of terminal D after generating electricity has started. 5. Then, alternator indicator relay 1 (8) is not excited. Current from alternator indicator relay 1 (8) flows to monitor controller (10). Monitor controller (10) puts out the alternator indicator. 6. At the same time, current from alternator indicator relay 1 (8) also flows to ICF (11).

T2-5-16

SECTION 2 SYSTEM Group 5 Electrical System

#2-28 8 9

11 D 7

TNCB-02-05-006

1234-

Key Switch Terminal B Terminal M Battery

5678-

Battery Relay Fusible Link A Alternator Alternator Indicator Relay 1

9- Alternator Indicator Relay 2 10- Monitor Controller 11- ICF

T2-5-17

SECTION 2 SYSTEM Group 5 Electrical System Alternator Operation

Regulator Operation

1. Alternator (6) consists of field coil FC, stator coil SC, and diodes (5).

1. Regulator (4) is an IC chip, which maintains generating voltage at a constant level.

2. At the beginning, no current is flowing through field coil FC. When the rotor rotates, alternate current is generated in stator coil SC due to the rotor remain magnetism.

2. When generating voltage exceeds the set voltage, regulator (4) reduces current through field coil FC. Therefore, generating voltage of stator coil SC decreases.

3. When current flows through field coil FC, the rotor is further magnetized so that the generating voltage increases. Therefore, generating voltage increases further and the battery starts charging.

3. When generating voltage becomes lower than the set voltage, regulator (4) increases current through field coil FC. Therefore, generating voltage of stator coil SC increases. 4. The above operation is repeated so that the alternator (6) generating voltage is kept constant.

T2-5-18

SECTION 2 SYSTEM Group 5 Electrical System

6 B

4 W

SC FC

TNCB-02-05-020

12-

Battery Battery Relay

34-

From Key Switch Terminal M Regulator

56-

T2-5-19

Diode Alternator

SECTION 2 SYSTEM Group 5 Electrical System Surge Voltage Prevention Circuit 1. When the engine is stopped (key switch (1): OFF position), current from terminal M (3) in key switch (1) disappears and battery relay (5) is turned OFF. 2. The engine continues to rotate due to inertia force just after key switch (1) is set to the OFF position so that alternator (10) continues to generate electricity. 3. As the generating current cannot flow to battery (4), surge voltage arises in the circuit and failures of the electronic components, such as the controller, possibly cause. In order to prevent the occurrence of surge voltage, the surge voltage prevention circuit is provided. 4. Current from battery (4) always flows to terminals #1 and #3 of load dump relay (7). 5. When current from terminal M (3) in key switch (1) stops flowing to terminal #2-28 of monitor controller (9), monitor controller (9) connects terminal #2-17 to the ground. 6. Current flows to the exciting circuit in load dump relay (7) and load dump relay (7) is turned ON. 7. Therefore, even if key switch (1) is set to the OFF position with the engine running, current from battery (4) continues to excite battery relay (5) through load dump relay (7). 8. In addition, when a fixed time has passed monitor controller (9) disconnects terminal #2-17 from the ground. Therefore, battery relay (5) is turned OFF.

T2-5-20

SECTION 2 SYSTEM Group 5 Electrical System

#2-17 8

#2-28 9

TNCB-02-05-007 1234-

Key Switch Terminal B Terminal M Battery

5678-

Battery Relay Fusible Link A Load Dump Relay Alternator Indicator Relay 1

9- Monitor Controller 10- Alternator

T2-5-21

SECTION 2 SYSTEM Group 5 Electrical System Engine Stop Circuit 1. When key switch (1) is set to the OFF position from the ON position, current indicating that key switch (1) is in the ON position stops flowing to terminal #K88 of ECM (7) from terminal M (3). 2. As no current flows from terminals A32, A33, A46, and A48 of ECM (7), ECM (7) stops fuel injection of the injector and stops the engine.

T2-5-22

SECTION 2 SYSTEM Group 5 Electrical System

7 K88

TNCB-02-05-008

123-

Key Switch Terminal B Terminal M

456-

Battery Battery Relay Fusible Link A

T2-5-23

ECM

SECTION 2 SYSTEM Group 5 Electrical System Pilot Shut-Off Circuit (Key Switch: ON) (Hydraulic Operated Type) (Option) y Control Level Lock Switch (9): ON (Lock) Position 1. When key switch (1) is in the ON position, current from battery relay (3) flows to pilot shut-off relay (7) through fusible link (100 A) (5), fuse #15 of fuse box A (6). 2. When control lever lock switch (9) is in the ON (lock) position, terminals #2 and #4 are connected inside control lever lock switch (9). 3. Pilot shut-off relay (7) (coil side) is connected to the ground through control lever lock switch (9). Then, pilot shut-off relay (7) is excited. 4. Current which flows to pilot shut-off solenoid valve (8) from pilot shut-off relay (7) (contact side) stops flowing. Then, pilot shut-off solenoid valve (8) is turned OFF. 5. Therefore, pressure oil which flows to the pilot valve from the HST charging pump is blocked by pilot shut-off solenoid valve (8). 6. Consequently, pressure oil from the HST charging pump is not supplied to the pilot valve. (Refer to Hydraulic System.) 7. Current from fuse #11 of fuse box A (6) flow to terminals #8 and #9 in control lever lock switch (9) and turn on the indicators of control lever lock switch (9).

T2-5-24

SECTION 2 SYSTEM Group 5 Electrical System

6 2

4 10

TNCB-02-05-009 123-

Key Switch Battery Battery Relay

456-

Fusible Link A Fusible Link (100A) Fuse Box A

789-

T2-5-25

Pilot Shut-Off Relay Pilot Shut-Off Solenoid Valve Control Lever Lock Switch

10- From Light Switch

SECTION 2 SYSTEM Group 5 Electrical System y Control Lever Lock Switch (9): OFF (Release) Position 1. When control lever lock switch (9) is set to the OFF (release) position, terminals #2 and #4 are disconnected inside control lever lock switch (9). Therefore, the ground in control lever lock switch (9) is disconnected. 2. Pilot shut-off relay (7) (coil side) is disconnected from the ground and pilot shut-off relay (7) is not excited. 3. Current flows to pilot shut-off solenoid valve (8) from pilot shut-off relay (7) (contact side). Then, pilot shut-off solenoid valve (8) is turned ON. 4. Therefore, pressure oil from the HST charging pump is supplied to the pilot valve through pilot shut-off solenoid valve (8).

T2-5-26

SECTION 2 SYSTEM Group 5 Electrical System

TNCB-02-05-010

123-

Key Switch Battery Battery Relay

456-

Fusible Link A Fusible Link (100A) Fuse Box A

789-

T2-5-27

Pilot Shut-Off Relay Pilot Shut-Off Solenoid Valve Control Lever Lock Switch

SECTION 2 SYSTEM Group 5 Electrical System (Blank)

T2-5-28

SECTION 2 SYSTEM Group 5 Electrical System Accessory Circuit The major functions and circuits in the accessory circuit are as follows. x Wiper Circuit: Operates the intermittent operation of wiper and the washer. x Cab Light Circuit: Turns on/off the cab light by shifting the switch or by opening/closing the door.

T2-5-29

SECTION 2 SYSTEM Group 5 Electrical System Wiper/Washer Circuit

c b

Front Wiper Circuit (Front Wiper Switch (6)): INT) 1. When front wiper switch (6) is set to INT. position (a), the signals according to the set intervals are sent to monitor controller (8).

2. Monitor controller (8) connects terminal #2-19 to the ground inside according to the input intervals. 3. Therefore, wiper relay (F) 1 (3) is turned ON QOFF repeatedly. MNEC-01-076

4. When wiper relay (F) 1 (3) is ON, current from fuse #3 of fuse box B (7) flow to wiper motor (F) (1) and the front wiper is operated at slow speed.

Front Wiper Switch ab-

T2-5-30

INT. Position Slow Position

cd-

Fast Position Washer Switch

SECTION 2 SYSTEM Group 5 Electrical System

2 1

3 5

b c d

#1-20

#2-19

TNCB-02-05-012

ab-

INT. Position Slow Position

Fast Position

Washer Switch

123-

Wiper Motor (F) Wiper Relay (F) 2 Wiper Relay (F) 1

456-

Washer Motor Washer Relay (F) Front Wiper Switch

78-

Fuse Box B Monitor Controller

T2-5-31

SECTION 2 SYSTEM Group 5 Electrical System Front Wiper Circuit (Front Wiper Switch (6)): Slow)

c b

1. When front wiper switch (6) is set to slow position (b), monitor controller (8) turns ON wiper relay (F) 1 (3).

2. Current from fuse #3 of fuse box B (7) flow to wiper motor (F) (1) and the front wiper is operated at slow speed.

MNEC-01-076

Front Wiper Switch ab-

T2-5-32

INT. Position Slow Position

cd-

Fast Position Washer Switch

SECTION 2 SYSTEM Group 5 Electrical System

3 4

b c d

#1-29

#2-19

TNCB-02-05-013

ab-

INT. Position Slow Position

Fast Position

Washer Switch

123-

Wiper Motor (F) Wiper Relay (F) 2 Wiper Relay (F) 1

456-

Washer Motor Washer Relay (F) Front Wiper Switch

78-

Fuse Box B Monitor Controller

T2-5-33

SECTION 2 SYSTEM Group 5 Electrical System Front Wiper Circuit (Front Wiper Switch (6)): Fast)

c b

1. When front wiper switch (6) is set to fast position (c), monitor controller (8) turns ON wiper relay (F) 1 (3) and wiper relay (F) 2 (2).

2. Current from fuse #3 of fuse box B (7) flow to wiper motor (F) (1) and the front wiper is operated at fast speed.

MNEC-01-076

Front Wiper Switch ab-

T2-5-34

INT. Position Slow Position

cd-

Fast Position Washer Switch

SECTION 2 SYSTEM Group 5 Electrical System 2

3 4

b c d

#1-30 8

#2-18 #2-19 TNCB-02-05-014

ab-

INT. Position Slow Position

Fast Position

Washer Switch

123-

Wiper Motor (F) Wiper Relay (F) 2 Wiper Relay (F) 1

456-

Washer Motor Washer Relay (F) Front Wiper Switch

78-

Fuse Box B Monitor Controller

T2-5-35

SECTION 2 SYSTEM Group 5 Electrical System Front Washer Circuit 1. While washer switch (d) is pushed, front wiper switch (6) is connected to the ground and washer relay (F) (4) is excited.

c b

2. Current from fuse #3 of fuse box B (7) flow to washer motor (F) (5) and washer liquid is jetted.

3. In addition, when washer switch (d) is pushed beyond 1.4 seconds, monitor controller (8) turns ON wiper relay (F) 1 (3). 4. Therefore, the washer and front wiper are operated at slow speed at the same time.

MNEC-01-076

Front Wiper Switch ab-

T2-5-36

INT. Position Slow Position

cd-

Fast Position Washer Switch

SECTION 2 SYSTEM Group 5 Electrical System 2 1

3 4

b c d

#1-34 8

#2-19 TNCB-02-05-015

ab-

INT. Position Slow Position

Fast Position

Washer Switch

123-

Wiper Motor (F) Wiper Relay (F) 2 Wiper Relay (F) 1

456-

Washer Motor Washer Relay (F) Front Wiper Switch

78-

Fuse Box B Monitor Controller

T2-5-37

SECTION 2 SYSTEM Group 5 Electrical System Rear Washer Circuit c b

1. When rear wiper switch (1) is set to washer position (a), rear wiper switch (1) is connected to the ground and washer relay (R) (5) is excited.

2. Current from fuse #6 of fuse box B (2) flow to washer motor (R) (6) and washer liquid is jetted.

MNEC-01-077

Rear Wiper Switch ab-

T2-5-38

Washer Position Wiper Position

Wiper, Washer Position

SECTION 2 SYSTEM Group 5 Electrical System

TNCB-02-05-016

12-

Rear Wiper Switch Fuse Box B

34-

Wiper Relay (R) Wiper Motor (R)

56-

T2-5-39

Washer Relay (R) Washer Motor (R)

SECTION 2 SYSTEM Group 5 Electrical System Rear Wiper Circuit c

1. When rear wiper switch (1) is set to wiper position (b), rear wiper switch (1) is connected to the ground and wiper relay (R) (3) is turned ON.

2. Current from fuse #6 of fuse box B (2) flow to wiper motor (R) (4) and the rear wiper is operated.

MNEC-01-077

Rear Wiper Switch ab-

T2-5-40

Washer Position Wiper Position

Wiper, Washer Position

SECTION 2 SYSTEM Group 5 Electrical System

b c

TNCB-02-05-017

12-

Rear Wiper Switch Fuse Box B

34-

Wiper Relay (R) Wiper Motor (R)

56-

T2-5-41

Washer Relay (R) Washer Motor (R)

SECTION 2 SYSTEM Group 5 Electrical System Rear Wiper, Washer Circuit c b

1. When rear wiper switch (1) is set to wiper, washer position (c), rear wiper switch (1) is connected to the ground, wiper relay (R) (3) is turned ON and washer relay (R) (5) is excited.

2. Current from fuse #6 of fuse box B (2) flow to wiper motor (R) (4) and washer motor (R) (6) so that the rear wiper is operated and washer liquid is jetted.

MNEC-01-077

Rear Wiper Switch ab-

T2-5-42

Washer Position Wiper Position

Wiper, Washer Position

SECTION 2 SYSTEM Group 5 Electrical System

a b c

TNCB-02-05-018

12-

Rear Wiper Switch Fuse Box B

34-

Wiper Relay (R) Wiper Motor (R)

56-

T2-5-43

Washer Relay (R) Washer Motor (R)

SECTION 2 SYSTEM Group 5 Electrical System Cab Light Circuit Front Cab Light Circuit

Rear Cab Light Circuit

1. When front cab light switch (3) is set to neutral position (4), front cab light (2) is connected to the ground through door open/close switch (6).

1. When rear cab light switch (8) is set to the ON position, rear cab light (7) is connected to the ground.

2. When the cab door is opened, door open/close switch (6) is turned ON. Current from fuse #11 of fuse box B (1) flow to front cab light (2) and turns on front cab light (2).

2. Current from fuse #11 of fuse box B (1) flow to rear cab light (7) and turns on rear cab light (7).

3. When the cab door is closed, door open/close switch (6) is turned OFF. Door open/close switch (6) is disconnected from the ground and cab light (2) is tuned off. 4. When front cab light switch (3) is set to ON position (5), front cab light (2) is connected to the ground. 5. Current from fuse #11 of fuse box B (1) flow to front cab light (2) and turns on cab light (2).

T2-5-44

SECTION 2 SYSTEM Group 5 Electrical System

TNCB-02-05-019

12-

Fuse Box B Front Cab Light

34-

Front Cab Light Switch Neutral Position

56-

T2-5-45

ON Position Door Open/Close Switch

78-

Rear Cab Light Rear Cab Light Switch

SECTION 2 SYSTEM Group 5 Electrical System (Blank)

T2-5-46

SECTION 2 SYSTEM Group 5 Electrical System Light/Horn Circuit x Light Circuit: Turns on and off head lights, clearance lights, and license lights. x Work Light Circuit: Turns on and off the work light. x Turn Signal Light Circuit: Turns on and off turn signal lights. x Brake Light Circuit: Turns on and off brake lights. x Hazard Light Circuit: Turns on and off hazard lights. x Horn Circuit: Sounds the horn. x Parking Brake Circuit: Applies and releases the parking brake. x Backup Light/Buzzer Circuit: Turns on and off backup lights and the buzzer. (Refer to p. T2-2-46 Backup Light Lighting Control.)

T2-5-47

SECTION 2 SYSTEM Group 5 Electrical System Light Circuit Light Switch: S Position 1. Current from battery (2) flows to light switch (6) through fusible link (A) (4), fuse #17 of fuse box A (5). 2. When light switch (6) is set to the S position, current from terminal S (7) in light switch (6) flows to clearance lights (8, 9, 11, 12) and license light (option) (10) through fuse #11 of fuse box A (5). 3. Therefore, clearance lights (8, 9, 11, 12) and license light (option) (10) are turned on. 4. At the same time, current from terminal S (7) in light switch (6) flows to monitor controller (13) and turns on the clearance light indicator.

T2-5-48

SECTION 2 SYSTEM Group 5 Electrical System

1 5

3 8 9 10

4 11 12 7

13 #1-25

TNCB-02-05-021

1234-

Key Switch Battery Battery Relay Fusible Link A

5678-

Fuse Box A Light Switch Terminal S Clearance Light (Rear) (RH)

9101112-

T2-5-49

Clearance Light (Rear) (LH) License Light (Option) Clearance Light (Front) (RH) Clearance Light (Front) (LH)

13- Monitor Controller

SECTION 2 SYSTEM Group 5 Electrical System Light Switch (9): H Position 1. When key switch (1) is set to the ON position, terminal B (2) is connected to terminal M (3) in key switch (1). 2. Current from terminal M (3) flows through fuse #13 of fuse box A (8) and excites battery relay (5). 3. When light switch (9) is set to the H position, terminal S (10) is connected to terminal H (11) in light switch (9). 4. When dimmer switch (14) is in low-beam position (12), current from terminal H (11) flows to head light relay (15) (coil side) through dimmer switch (14) and excites head light relay (15). 5. Current from battery relay (5) flows to head lights (16, 19) through fuse #9 of fuse box A (8), head light relay (15) and turns on low-beams (17, 18).

T2-5-50

SECTION 2 SYSTEM Group 5 Electrical System

9 10

12 13 14

TNCB-02-05-022

12345-

Key Switch Terminal B Terminal M Battery Battery Relay

678910-

Fusible Link A Fusible Link (100 A) Fuse Box A Light Switch Terminal S

1112131415-

T2-5-51

Terminal H Lo (Low-Beam) Position Hi (High-Beam) Position Dimmer Switch Head Light Relay

16171819-

Head Light (RH) Low-Beam (RH) Low-Beam (LH) Head Light (LH)

SECTION 2 SYSTEM Group 5 Electrical System High-Beam Circuit 1. When light switch (9) is in the H position and dimmer switch (14) is in Hi (high-beam) position (13), current from terminal H (11) flows to highbeam relay (15) (coil side) through dimmer switch (14) and excites high-beam relay (15). 2. Current from battery relay (5) flows to head lights (16, 19) through fuse #19 of fuse box A (8), highbeam relay (15) and turns on high-beams (17, 18). 3. At the same time, current from high-beam relay (15) flows to monitor controller (20) and turns on the high-beam indicator.

T2-5-52

SECTION 2 SYSTEM Group 5 Electrical System

9 10

12 13 14

TNCB-02-05-023

12345-

Key Switch Terminal B Terminal M Battery Battery Relay

678910-

Fusible Link A Fusible Link (100 A) Fuse Box A Light Switch Terminal S

1112131415-

T2-5-53

Terminal H Lo (Low-Beam) Position Hi (High-Beam) Position Dimmer Switch High-Beam Relay

1617181920-

Head Light (RH) High-Beam (RH) High-Beam (LH) Head Light (LH) Monitor Controller

SECTION 2 SYSTEM Group 5 Electrical System Work Light Circuit 1. When key switch (1) is set to the ON position, terminal B (2) is connected to terminal M (3) in key switch (1). 2. Current from terminal M (3) flows through fuse #13 of fuse box A (8) and excites battery relay (5). 3. Current from battery (4) flows to light switch (10) through battery relay (5), fusible link (A) (6), fuse #17 of fuse box A (8). 4. When light switch (10) is set to the S position or H position, current flows to work light switch (13) from light switch (10) and turns on switch light (20) of work light switch (13). 5. When front work light position (14) of work light switch (13) is pushed, terminals #1 and #2 are connected inside work light switch (13). 6. Current from terminal #2 of work light switch (13) flows to front work light relay (16) and excites it. 7. Current from fuse #5 of fuse box B (9) flows to front work lights (17, 18) through front work light relay (16) and turns on front work lights (17, 18). 8. At the same time, current from fuse #5 of fuse box B (9) flows to monitor controller (19) and turns on the work light indicator.

T2-5-54

SECTION 2 SYSTEM Group 5 Electrical System

19 7

#2-12

10 12

16 13 9

17 15

TNCB-02-05-025 123456789-

Key Switch Terminal B Terminal M Battery Battery Relay Fusible Link A Fusible Link (100 A) Fuse Box A Fuse Box B

101112131415-

Light Switch Terminal S Terminal H Work Light Switch Front Work Light Position Front and Rear Work Light Position 16- Front Work Light Relay 17- Front Work Light (RH)

18- Front Work Light (LH) 19- Monitor Controller 20- Switch Light

T2-5-55

SECTION 2 SYSTEM Group 5 Electrical System 9. When front and rear work light position (15) of work light switch (13) is pushed, terminals #1 and #3 and terminals #4 and #5 are connected inside work light switch (13) respectively. 10. Current from terminal #3 of work light switch (13) flows to front work light relay (16) and excites it. 11. Current from fuse #5 of fuse box B (9) flows to front work lights (17, 18) through front work light relay (16) and turns on front work lights (17, 18). 12. At the same time, current from fuse #5 of fuse box B (9) flows to monitor controller (19) and turns on the work light indicator. 13. Current from terminal #5 of work light switch (13) flows to rear work light relay (21) and excites it. 14. Current from battery (13) flows to rear work lights (22, 23) through battery relay (5), fuse #16 of fuse box A (8), and rear work light relay (21) and turns on rear work lights (22, 23).

T2-5-56

SECTION 2 SYSTEM Group 5 Electrical System

19 7

#2-12

10 12

16 13 9

17 15

18 21 20

TNCB-02-05-024

123456-

Key Switch Terminal B Terminal M Battery Battery Relay Fusible Link A

789101112-

Fusible Link (100 A) Fuse Box A Fuse Box B Light Switch S Position H Position

13- Work Light Switch 14- Front Work Light Position 15- Front and Rear Work Light Position 16- Front Work Light Relay 17- Front Work Light (RH)

T2-5-57

181920212223-

Front Work Light (LH) Monitor Controller Switch Light Rear Work Light Relay Rear Work Light (RH) Rear Work Light (LH)

SECTION 2 SYSTEM Group 5 Electrical System Turn Signal Light Circuit 1. Current from battery (4) flows to flasher (9), turn signal light relay (R) (13) (contact side), and turn signal light relay (L) (14) (contact side) through fusible link A (6), and fuse #6 of fuse box A (8). 2. In addition, current from battery (4) flows to turn signal light switch (10) through battery relay (5), fuse #3 of fuse box A (8). 3. When the turn signal lever is set to left-turn position (11), current from terminal L in turn signal light switch (10) flows to turn signal light relay (L) (14) (coil side) and excites turn signal light relay (L) (14). 4. Current from flasher (9) flows to turn signal lights (17, 18) through turn signal light relay (L) (14). 5. As current from flasher (9) flows intermittently, turn signal lights (17, 18) blink. 6. At the same time, current from flasher (9) flows to monitor controller (19) and the left-turn signal light indicator blinks.

T2-5-58

SECTION 2 SYSTEM Group 5 Electrical System

#2-14

19 9 7

15 11

10 12

17 18

TNCB-02-05-026

12345-

Key Switch Terminal B Terminal M Battery Battery Relay

678910-

Fusible Link A Fusible Link (100 A) Fuse Box A Flasher Turn Signal Light Switch

1112131415-

T2-5-59

Left-Turn Position Right-Turn Position Turn Signal Light Relay (R) Turn Signal Light Relay (L) Turn Signal Light (Right Front)

16171819-

Turn Signal Light (Right Rear) Turn Signal Light (Left Front) Turn Signal Light (Left Rear) Monitor Controller

SECTION 2 SYSTEM Group 5 Electrical System 7. When the turn signal lever is set to right-turn position (12), current from terminal R in turn signal light switch (10) flows to turn signal light relay (R) (13) (coil side) and excites turn signal light relay (R) (13). 8. Current from flasher (9) flows to turn signal lights (15, 16) through turn signal light relay (R) (13). 9. As current from flasher (9) flows intermittently, turn signal lights (15, 16) blink. 10. At the same time, current from flasher (9) flows to monitor controller (19) and the right-turn signal light indicator blinks.

T2-5-60

SECTION 2 SYSTEM Group 5 Electrical System

#2-15 9 7

15 11

10 12

17 18

TNCB-02-05-027 12345-

Key Switch Terminal B Terminal M Battery Battery Relay

678910-

Fusible Link A Fusible Link (100 A) Fuse Box A Flasher Turn Signal Light Switch

1112131415-

T2-5-61

Left-Turn Position Right-Turn Position Turn Signal Light Relay (R) Turn Signal Light Relay (L) Turn Signal Light (Right Front)

16171819-

Turn Signal Light (Right Rear) Turn Signal Light (Left Front) Turn Signal Light (Left Rear) Monitor Controller

SECTION 2 SYSTEM Group 5 Electrical System Brake Light Circuit 1. When key switch (1) is set to the ON position, terminal B (2) is connected to terminal M (3) in key switch (1). 2. Current from terminal M (3) flows through fuse #13 of fuse box A (8) and excites battery relay (5). 3. Current from battery (4) flows to brake light relay (9) through battery relay (5), and fuse #3 of fuse box A (8). 4. When the brake pedal (service brake) is depressed, brake light switch (12) is turned ON and brake light relay (9) (coil side) is connected to the ground. 5. Brake light relay (9) is excited. Current from fuse #3 of fuse box A (8) flows to brake lights (10, 11) at both sides through brake light relay (9). Then, brake lights (10, 11) are turned on. 6. In addition, current from brake light relay (9) flows to MC. 7. MC stops the forward or rear side solenoid valve of forward/reverse control solenoid valve. (Refer to Control System.)

T2-5-62

SECTION 2 SYSTEM Group 5 Electrical System

13 11 12 TNCB-02-05-028

1234-

Key Switch Terminal B Terminal M Battery

5678-

Battery Relay Fusible Link A Fusible Link (100 A) Fuse Box A

9101112-

T2-5-63

Brake Light Relay Brake Light (RH) Brake Light (LH) Brake Light Switch

13- To MC

SECTION 2 SYSTEM Group 5 Electrical System Hazard Light Circuit 1. Current from battery (2) flows to flasher (6), turn signal light relay (R) (14) (contact side), and turn signal light relay (L) (15) (contact side) through fusible link A (4), and fuse #6 of fuse box A (5). 2. In addition, current from fuse #6 of fuse box A (5) flows to hazard light switch (7). 3. When light switch (11) is set to S position (12) or H position (13), current flows to hazard light switch (7) from light switch (11) and turns on switch light 1 (9) of hazard light switch (7). 4. When hazard light switch (7) is set to ON position (8), current from hazard light switch (7) flows to turn signal light relay (R) (14) (coil side) and turn signal light relay (L) (15) (coil side). Then, turn signal light relay (R) (14) and turn signal light relay (L) (15) are excited respectively. 5. Current from flasher (6) flows to turn signal light relay (R) (14) and turn signal light relay (L) (15) respectively. 6. Current from turn signal light relay (L) (15) flows to turn signal lights (18, 19). 7. Current from turn signal light relay (R) (14) flows to turn signal lights (16, 17). 8. At the same time, current flows to hazard light switch (7) from turn signal light relay (R) (14) and turns on switch light 2 (10) of hazard light switch (7). 9. As current from flasher (6) flows intermittently, turn signal lights blink. 10. At the same time, current from flasher (6) flows to monitor controller (20) and the left-turn signal light indicator and right-turn signal light indicator blink.

T2-5-64

SECTION 2 SYSTEM Group 5 Electrical System

1 5

#2-15

#2-14

6 8

4 7

11 13 10

16 14 17

18 19

TNCB-02-05-029

12345-

Key Switch Battery Battery Relay Fusible Link A Fuse Box A

678910-

Flasher Hazard Switch ON Position Switch Light 1 Switch Light 2

1112131415-

T2-5-65

Light Switch S Position H Position Turn Signal Light Relay (R) Turn Signal Light Relay (L)

1617181920-

Turn Signal Light (Right Front) Turn Signal Light (Right Rear) Turn Signal Light (Left Front) Turn Signal Light (Left Rear) Monitor Controller

SECTION 2 SYSTEM Group 5 Electrical System Horn Circuit 1. Current from battery (1) flows to horn relay (5) through fusible link (A) (3), and fuse #5 of fuse box A (4). 2. When horn switch (7) or horn switch (joystick type lever) (8) is pushed, it is connected to the ground and horn relay (5) is excited. 3. Current from fuse #5 of fuse box A (4) flows to horn (6) and it sounds.

T2-5-66

SECTION 2 SYSTEM Group 5 Electrical System

6 5

7 3 8

TNCB-02-05-030

123-

Battery Battery Relay Fusible Link A

456-

Fuse Box A Horn Relay Horn

78-

T2-5-67

Horn Switch Horn Switch (Joystick Type Lever)

SECTION 2 SYSTEM Group 5 Electrical System Parking Brake Circuit 1. When key switch (1) is set to the ON position, terminal B (2) is connected to terminal M (3) in key switch (1). 2. Current from terminal M (3) flows through fuse #13 of fuse box A (8) and excites battery relay (5). 3. In addition, current from terminal M (3) flows to parking brake relay 1 (11) through fuse #14 of fuse box A (8). 4. Current from battery (4) flows to light switch (16) through battery relay (5), fusible link (A) (6), and fuse #17 of fuse box A (8). 5. When light switch (16) is set to S position (17) or H position (18), current from light switch (16) flows to parking brake switch (12) through fuse #11 of fuse box A (8) and turns on switch light (15). 6. Therefore, the parking brake can be operated.

T2-5-68

SECTION 2 SYSTEM Group 5 Electrical System

3 19 20 4

13 12 14

16 18

TNCB-02-05-031

12345-

Key Switch Terminal B Terminal M Battery Battery Relay

678910-

Fusible Link A Fusible Link (100 A) Fuse Box A Parking Brake Solenoid Valve Parking Brake Relay 2

1112131415-

T2-5-69

Parking Brake Relay 1 Parking Brake Switch OFF ON Switch Light

1617181920-

Light Switch S Position H Position Parking Brake Pressure Sensor Monitor Controller

SECTION 2 SYSTEM Group 5 Electrical System Parking brake is released (Parking Brake Switch: OFF) 1. When parking brake switch (12) is in ON (14), parking brake relay 1 (11) (coil side) is connected to the ground through parking brake switch (12) and parking brake relay 1 (11) is excited.

7. At the same time, current from parking brake relay 2 (10) (coil side) flows to parking brake relay 2 (10) (contact side) and the self-exciting circuit is formed. 8. Pressure oil from the brake/ transmission pump flows to the parking brake of transmission and releases it.

2. As the circuit between parking brake relay 1 (11) and parking brake relay 2 (10) is disconnected, current does not flow and parking brake solenoid valve (9) is not activated.

9. At this time, monitor controller (20) turns off the parking brake indicator according to the signals from parking brake pressure sensor (19).

3. When parking brake switch (12) is set to OFF (13), terminals #4 and #6 is connected inside parking brake switch (12).

10. When parking brake switch (12) is released, it returns to the neutral position. Therefore, current from terminal #6 in parking brake switch (12) stops flowing to parking brake relay 2 (10).

4. At the same time, as the circuit between terminals #1 and #2 in parking brake switch (12) is disconnected, parking brake relay 1 (11) is not excited. 5. Current from parking brake relay 1 (11) flows to the ground through parking brake relay 2 (10) (coil side) and parking brake switch (12) and excites parking brake relay 2 (10).

11. However, as the self-exciting circuit is formed in parking brake relay 2 (10), parking brake solenoid valve (9) continues to be operated until key switch (1) is set to the OFF position or parking brake switch (12) is set to ON (14).

6. Therefore, as parking brake solenoid valve (9) is connected to the ground, current from battery (4) flows to parking brake solenoid valve (9) through battery relay (5), and fuse #20 of fuse box A (8) and activates it.

T2-5-70

SECTION 2 SYSTEM Group 5 Electrical System

3 19 20 4

13 12 14

16 18

TNCB-02-05-032

12345-

Key Switch Terminal B Terminal M Battery Battery Relay

678910-

Fusible Link A Fusible Link (100 A) Fuse Box A Parking Brake Solenoid Valve Parking Brake Relay 2

1112131415-

T2-5-71

Parking Brake Relay 1 Parking Brake Switch OFF ON Switch Light

1617181920-

Light Switch S Position H Position Parking Brake Pressure Sensor Monitor Controller

SECTION 2 SYSTEM Group 5 Electrical System Parking brake is applied (Parking Brake Switch: ON) 1. When parking brake switch (12) is set to ON (14), terminal #1 of parking brake switch (12) is connected to the ground through terminal #2 and parking brake relay 1 (11) is excited. 2. Current which flows to parking brake relay 2 (10) from parking brake relay 1 (11) stops flowing. 3. Consequently, as parking brake relay 2 (10) is not excited, parking brake solenoid valve (9) is disconnected from the ground and is stopped. 4. As pressure oil from the brake/ transmission pump does not flow to the parking brake, the parking brake of transmission is applied. 5. As the signals from parking brake pressure sensor (19) stop, monitor controller (20) turns on the parking brake indicator.

T2-5-72

SECTION 2 SYSTEM Group 5 Electrical System

3 19 20 4

13 12 14

16 18

TNCB-02-05-033

12345-

Key Switch Terminal B Terminal M Battery Battery Relay

678910-

Fusible Link A Fusible Link (100 A) Fuse Box A Parking Brake Solenoid Valve Parking Brake Relay 2

1112131415-

T2-5-73

Parking Brake Relay 1 Parking Brake Switch OFF ON Switch Light

1617181920-

Light Switch S Position H Position Parking Brake Pressure Sensor Monitor Controller

SECTION 2 SYSTEM Group 5 Electrical System (Blank)

T2-5-74

SECTION 3

COMPONENT OPERATION CONTENTS Group 1 Pump Device Outline .................................................................................... T3-1-1 HST Pump .............................................................................. T3-1-2 Operational Principle......................................................... T3-1-3 Displacement Angle Control Cylinder ......................... T3-1-4 DA Valve ...............................................................................T3-1-10 Forward/Reverse Control Solenoid Valve.................T3-1-11 Cutoff Valve .........................................................................T3-1-15 High-Pressure Relief Valve .............................................T3-1-18 Low-Pressure Relief Valve...............................................T3-1-22 HST Charging Pump.........................................................T3-1-23 Main Pump, Brake/Transmission Pump ....................T3-1-24

Group 2 Control Valve Outline (Manually Operated Type) ............................... T3-2-1 Hydraulic Circuit .................................................................. T3-2-4 Main Relief Valve ................................................................. T3-2-6 Overload Relief Valve (Bucket: Rod Side).................... T3-2-8 Outline (Hydraulic Operated Type) (Option) ...........T3-2-13 Hydraulic Circuit ................................................................T3-2-16 Main Relief Valve ...............................................................T3-2-20 Overload Relief Valve .......................................................T3-2-22

Group 6 Transmission Outline .................................................................................... T3-6-1 Operation............................................................................... T3-6-2 Fast speed mode............................................................ T3-6-2 Slow speed mode .......................................................... T3-6-3 Parking Brake........................................................................ T3-6-4 Travel Mode Selector Valve ............................................. T3-6-6 Accumulator ......................................................................... T3-6-8 Solenoid Valve ...................................................................... T3-6-9 Travel Mode Selector Solenoid Valve ..................... T3-6-9 Parking Brake Solenoid Valve .................................... T3-6-9 ON/OFF Solenoid Valve .............................................T3-6-10

Group 7 Axle Outline .................................................................................... T3-7-1 Differential ............................................................................. T3-7-2 Purpose of Differential................................................. T3-7-3 Principle of Differential................................................ T3-7-4 Operation of Differential ............................................. T3-7-5 Torque Proportioning Differential (TPD) .................... T3-7-6 Limited Slip Differential (LSD) (Option)....................... T3-7-8 Service Brake ......................................................................T3-7-10 Final Drive / Axle Shaft ....................................................T3-7-12

Group 3 Priority Valve Outline .................................................................................... T3-3-1 Operation............................................................................... T3-3-2

Group 4 Steering Valve Outline .................................................................................... T3-4-1 Structure ................................................................................ T3-4-2 Operation............................................................................... T3-4-3 Steering (Left) ................................................................. T3-4-4 Steering (Right) .............................................................. T3-4-5 Neutral ............................................................................... T3-4-5

Group 5 HST Motor Outline .................................................................................... T3-5-1 Travel Motor .......................................................................... T3-5-4 Regulator ............................................................................... T3-5-5 Displacement Angle Control Solenoid Valve ............ T3-5-5 Motor Displacement Angle Control ............................. T3-5-6 Travel Control Solenoid Valve ......................................... T3-5-8 Flushing Valve ....................................................................T3-5-10

Group 8 Brake Valve Outline .................................................................................... T3-8-1 Structure ................................................................................ T3-8-2 Operation............................................................................... T3-8-4

Group 9 Others Propeller Shaft ..................................................................... T3-9-1 Inching Valve (Declutch Valve) ....................................... T3-9-2 Pilot Shut-Off Solenoid Valve (Only Hydraulic Pilot Type)(Option) ........................ T3-9-3 HST Cooler Bypass Check Valve ..................................... T3-9-5 Pilot Accumulator (Only Hydraulic Pilot Type) (Option) ....................... T3-9-6 Ride Control Accumulator (Option) ............................. T3-9-7 Secondary Steering Check Block (Option) ................. T3-9-8 Secondary Steering Pump (Option) ............................. T3-9-9 Oil Filter ................................................................................T3-9-10

60Z7 F&S (US)

Group 10 Ride Control Valve Outline ..................................................................................T3-10-1 Ride Control Hydraulic Circuit ................................T3-10-2 Layout ..............................................................................T3-10-3 Operation .......................................................................T3-10-3 Charge-Cut Spool .............................................................T3-10-6 Overload Relief Valve .......................................................T3-10-8 Drain Plug ......................................................................... T3-10-12

Group 11 Pilot Valve Joystick Type Pilot Valve for Front Attachment (Hydraulic Pilot Type) (Option) ...............................T3-11-1 Outline.............................................................................T3-11-1 Operation .......................................................................T3-11-3 Electromagnetic Detent......................................... T3-11-10 Auxiliary Pilot Valve (Hydraulic Pilot Type) (Option) ......................... T3-11-11 Outline.......................................................................... T3-11-11 Operation .................................................................... T3-11-12 Auxiliary Joystick Type Pilot Valve) (Hydraulic Pilot Type)(Option) .......................... T3-11-17 Outline.......................................................................... T3-11-17 Operation .................................................................... T3-11-18

60Z7 F&S (US)

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Outline The pump device consists of HST pump (3), main pump (5), and brake/ transmission pump (6). HST pump (3) is a swash-plate type variable displacement axial plunger pump. Main pump (5) and brake/ transmission pump (6) are gear pumps.

6 a A

7 T4FJ-01-02-012

View A

T4FJ-01-02-013 a-

Engine Side

Forward/Reverse Control Solenoid Valve Cutoff Valve HST Pump

23-

4567-

HST Charging Pump Main Pump Brake/ Transmission Pump Low-Pressure Relief Valve

89-

T3-1-1

DA Valve High-Pressure Relief Valve (Forward Circuit Side)

10- Displacement Angle Control Cylinder 11- High-Pressure Relief Valve (Reverse Circuit Side)

SECTION 3 COMPONENT OPERATION Group 1 Pump Device HST Pump The HST pump supplies pressurized oil that drives the HST motor. Shaft (1) is connected to cylinder block (3) by a spline joint, and plunger (2) is inserted into cylinder block (3). When shaft (1) rotates, cylinder block (3) also rotates. Plunger (2) slides along the shoe plate and reciprocates in cylinder block (3) due to the inclination of swash plate (4) so that pressurized oil is drawn and delivered. The HST pump provides a displacement angle control cylinder for selecting delivery port and controlling delivery flow rate, a forward/reverse control solenoid valve, and a DA valve. 2

T4FJ-03-01-001

Shaft

Plunger

T3-1-2

Cylinder Block

Swash Plate

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Operational Principle Engine torque is transferred to shaft (1) and causes cylinder block (3) to rotate. Shoe (5) at the end of plunger (2) slides along the surface on swash plate (4). Plunger (2) reciprocates in the cylinder block (3) bore due to the inclination and pressurized oil is drawn and delivered.

3 T8UC-03-01-002

12-

Shaft Plunger

Cylinder Block

T3-1-3

Swash Plate

Shoe

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Displacement Angle Control Cylinder Displacement angle control cylinder (1) changes the displacement angle of swash plate (4) in the HST pump by receiving pressurized oil from the forward/reverse control solenoid valve. The delivery port of the HST pump is selected to forward, neutral, and reverse according to the displacement angle of swash plate (4).

Section A

The major parts of displacement angle control cylinder (1) are servo piston (3), outer spring (7), inner spring (6), spring guides (5, 8), and stopper ring (2). 3

As servo piston (3) is connected to swash plate (4) in the HST pump, the displacement angle of swash plate (4) is changed according to movement of servo piston (3). 4

5 A

6 7 8

T4FJ-01-02-012 T4FJ-03-01-002

12-

Displacement Angle Control Cylinder Stopper Ring

345-

Servo Piston Swash Plate Spring Guide

678-

T3-1-4

Inner Spring Outer Spring Spring Guide

SECTION 3 COMPONENT OPERATION Group 1 Pump Device In Neutral: When the displacement angle control cylinder is in neutral, swash plate (4) is not tilted, plunger (2) does not reciprocate in the cylinder block (3) bore. Although the HST pump rotates, pressurized oil is not drawn and delivered.

T4FJ-03-01-003

12-

Shaft Plunger

34-

Cylinder Block Swash Plate

T3-1-5

Chamber A

Chamber B

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Forward: 1. Pressurized oil from forward/reverse control solenoid valve (7) flows to chamber A (5) in the displacement angle control cylinder. 2. Servo piston (8) moves and changes the displacement angle of swash plate (4) to the forward position. 3. The HST pump delivers pressurized oil from port B. 4. As servo piston (8) has moved, pressurized oil from chamber B (6) of the displacement angle control cylinder returns to the hydraulic oil tank through the return circuit of forward/reverse control solenoid valve (7).

6 4

8 T4FJ-03-01-016 123-

Shaft Plunger Cylinder Block

456-

Swash Plate Chamber A Chamber B

78-

T3-1-6

Forward/Reverse Control Solenoid Valve Servo Piston

SECTION 3 COMPONENT OPERATION Group 1 Pump Device

3 8 5 e

4 f

T4FJ-03-01-004

cd-

Signal from MC Forward

From Forward/Reverse Control Solenoid Valve

To Hydraulic Oil Tank

123-

Shaft Plunger Cylinder Block

456-

Swash Plate Chamber A Chamber B

Forward/Reverse Control Solenoid Valve Servo Piston

T3-1-7

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Reverse: 1. Pressurized oil from forward/reverse control solenoid valve (7) flows to chamber B (6) in the displacement angle control cylinder. 2. Servo piston (8) moves and changes the displacement angle of swash plate (4) to the reverse position. 3. The HST pump delivers pressurized oil from port A. 4. As servo piston (8) has moved, pressurized oil from chamber A (5) of the displacement angle control cylinder returns to the hydraulic oil tank through the return circuit of forward/reverse control solenoid valve (7).

8 T4FJ-03-01-017

123-

Shaft Plunger Cylinder Block

456-

Swash Plate Chamber A Chamber B

78-

T3-1-8

Forward/Reverse Control Solenoid Valve Servo Piston

SECTION 3 COMPONENT OPERATION Group 1 Pump Device

g 1

3 8

5 f

4 h

T4FJ-03-01-005

cf-

Signal from MC To Hydraulic Oil Tank

Reverse

From Forward/Reverse Control Solenoid Valve

123-

Shaft Plunger Cylinder Block

456-

Swash Plate Chamber A Chamber B

Forward/Reverse Control Solenoid Valve Servo Piston

T3-1-9

SECTION 3 COMPONENT OPERATION Group 1 Pump Device DA Valve The DA valve is shifted by the HST charge pressure. The DA valve controls the flow rate of pressurized oil which flows from the DA valve to the forward/reverse control solenoid valve in order to control the signal pressure between the forward/reverse control solenoid valve and the displacement angle control cylinder. The displacement angle control cylinder changes the displacement angle of swash plate in HST pump according to the signal pressure from the forward/reverse control solenoid valve. Then, delivery flow rate of the HST pump is changed.

Operation

NOTE: DA stands for Automatische Verstellung

3. When pressure in port P1 reaches the set force of spring (5), spool (4) moves.

1. Pressurized oil flows to port P1, flows to the cylinder block through the spool and port P2, and flows to the forward/reverse control solenoid valve through port P3. 2. Pressure in port P1 is routed to orifice (3) of spool (4).

drehzahlabhängig (German), which means speedrelated automatic hydraulic control.

4. The outlet to port P2 is restricted by spool (4) and hole (2) of spool (4) is connected to port P3.

5. Pressurized oil flowing to the cylinder block is decreased and pressurized oil in spool (4) flows to the forward/reverse control solenoid valve through hole (2) and port P3.

P2 c

T81S-03-01-008

a P2

3 b P1

T4FJ-03-01-100

To Forward/Reverse Control Solenoid Valve

From HST Charging Pump

To Cylinder Block

12-

Rod Hole

34-

Orifice Spool

Spring

T3-1-10

Spring Seat

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Forward/Reverse Control Solenoid Valve The forward/reverse control solenoid valve consists of forward side solenoid valve (1), reverse side solenoid valve (3), and spool (2). Forward side solenoid valve (1) and reverse side solenoid valve (3) are ON/OFF solenoid valves.

Section A

Forward side solenoid valve (1) or reverse side solenoid valve (3) is turned ON according to the position of the forward/reverse lever. Then, the signal pressure is sent to the displacement angle control cylinder.

The displacement angle control cylinder changes the delivery port of the HST pump to forward or reverse.

T4FJ-01-02-012

T4FJ-03-01-006

Forward Side Solenoid Valve

Spool

T3-1-11

Reverse Side Solenoid Valve

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Forward Travel 1. When setting the forward/reverse lever to the forward position, forward side solenoid valve (1) is excited and spool (2) moves upward.

2. Port P is connected to port A. 3. Pressurized oil from the DA valve flows to port P and flows to the displacement angle control cylinder through the spool (2) clearance and port A. 2

4. Returning oil from the displacement angle control cylinder flows to port B and returns to the hydraulic oil tank through reverse side solenoid valve (3) and port T.

A T

P B

T4FJ-03-01-007 PA-

Port P Port A

123-

Forward Side Solenoid Valve Spool Reverse Side Solenoid Valve

T3-1-12

BT-

Port B Port T

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Reverse Travel 1. When setting the forward/reverse lever to the reverse position, reverse side solenoid valve (3) is excited and spool (2) moves downward.

2. Port P is connected to port B. 3. Pressurized oil from the DA valve flows to port P and flows to the displacement angle control cylinder through the spool (2) clearance and port B. 4. Returning oil from the displacement angle control cylinder flows to port A and returns to the hydraulic oil tank through forward side solenoid valve (1) and port T.

A P

T4FJ-03-01-008 PA-

Port P Port A

123-

Forward Side Solenoid Valve Spool Reverse Side Solenoid Valve

T3-1-13

BT-

Port B Port T

SECTION 3 COMPONENT OPERATION Group 1 Pump Device (Blank)

T3-1-14

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Cutoff Valve The cutoff valve regulates the maximum circuit pressure and protects the circuit on the high-pressure side.

p B

When the high-pressure side in the travel circuit reaches the specified circuit pressure, the cutoff valve decreases the control pressure that is routed to the displacement angle control cylinder through the forward/reverse control solenoid valve.

T81S-03-01-019

When the control pressure routed to the displacement angle control cylinder is decreased, the displacement angle of HST pump is controlled.

AB-

The heat generation can be minimized as the circuit pressure on the high-pressure side is regulated by the pump flow rate control. The high-pressure relief valve functions as a safety valve and the cutoff valve regulates the circuit pressure on the high-pressure side. Therefore, the cutoff valve pressure is usually set at 2 to 3 MPa (20 to 31 kgf/cm2, 290 to 435 psi) lower than that of the high-pressure relief valve.

T3-1-15

Port A Port B

Displacement Angle Control Cylinder Control Pressure Oil

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Forward Operation: 1. When forward travel pressure (b) increases, pressurized oil from port B is routed to spool 1 (5) and moves it to the left. 2. When forward travel pressure (b) further increases, pressurized oil from port B is routed to piston (3) through passage (4) in spool 1 (5). 3. When the pressure routed to piston (3) reaches the set force of spring (1), spool 2 (2) is moved to the left through piston (3). 4. Displacement angle control cylinder control pressurized oil (p) of HST pump flowing to the forward/reverse control solenoid valve flows to hydraulic oil tank (c) through spool 2 (2). 5. Therefore, pressurized oil which is routed to the displacement angle control cylinder through the forward/reverse control solenoid valve decreases.

p A

5 T4FJ-03-01-010

12-

Displacement Angle Control Cylinder Control Pressure Oil

Aa-

Port A Reverse Travel Pressure

Bb-

Port B Forward Travel Pressure

Spring Spool 2

34-

Piston Passage

Spool 1

T3-1-16

To Hydraulic Oil Tank

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Reverse Operation: 1. When reverse travel pressure (a) increases, pressurized oil from port A is routed to spool 1 (5) and moves it to the right. 2. When reverse travel pressure (a) further increases, the inner pressure in spool 1 (5) increases and pressurized oil from port A is routed to piston (3). 3. When the pressure routed to piston (3) reaches the set force of spring (1), spool 2 (2) is moved to the left through piston (3). 4. Displacement angle control cylinder control pressure oil (p) of HST pump flowing to the forward/ reverse control solenoid valve flows to hydraulic oil tank (c) through spool 2 (2). 5. Therefore, pressurized oil which is routed to the displacement angle control cylinder through the forward/reverse control solenoid valve decreases.

p A

5 T4FJ-03-01-009

12-

Displacement Angle Control Cylinder Control Pressure Oil

Aa-

Port A Reverse Travel Pressure

Bb-

Port B Forward Travel Pressure

Spring Spool 2

34-

Piston Passage

Spool 1

T3-1-17

To Hydraulic Oil Tank

SECTION 3 COMPONENT OPERATION Group 1 Pump Device High-Pressure Relief Valve The high pressure relief valve regulates the maximum pressure of the travel circuit and protects the circuit on the high-pressure side. In addition, it has the make-up function for HST charging. When the pressurized oil flow rate to the suction side circuit is insufficient, pressurized oil from the HST charging pump is routed to the suction side circuit.

Relief Operation 1. Pressure in port HP (travel circuit) is routed to pilot poppet (6) through orifice (9) in piston (8). 2. When pressure in port HP reaches the set pressure of spring C (4), pilot poppet (6) is opened. Pressurized oil flows to passage (5) and flows to port LP (hydraulic oil tank) through the external circumference of main poppet (3). 3. At this time, a pressure difference is caused between port HP and spring chamber (7) due to orifice (9). 4. When this pressure difference reaches the set pressure of spring A (2) and spring B (1), piston (8) and main poppet (3) are opened and pressurized oil in port HP flows to port LP. 5. Consequently, the pressure in the travel circuit decreases. 6. When the pressure in the travel circuit decreases to the specified pressure, piston (8) and main poppet (3) are closed by the force of spring A (2) and spring B (1).

T3-1-18

SECTION 3 COMPONENT OPERATION Group 1 Pump Device During Normal Operation: 1

7 T4FJ-03-01-011

During Relief Operation:

7 T4FJ-03-01-012

HP- Port HP

LP- Port LP

123-

456-

Spring B Spring A Main Poppet

Spring C Passage Pilot Poppet

78-

T3-1-19

Spring Chamber Piston

9- Orifice 10- Sleeve

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Make-Up Operation 1. When pressure in port HP (travel circuit) decreases lower than pressure in port LP (hydraulic oil tank), main poppet (3) is moved to the right. 2. Pressurized oil in port LP flows to port HP and cavitation is prevented. 3. When pressure at the port HP side increases to the specified pressure, main poppet (3) is closed by the force of spring A (2) and spring B (1).

T3-1-20

SECTION 3 COMPONENT OPERATION Group 1 Pump Device During Make-Up Operation:

T4FJ-03-01-013 HP- Port HP

LP- Port LP

Spring B

Spring A

T3-1-21

Main Poppet

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Low-Pressure Relief Valve The low-pressure relief valve regulates the HST charge pressure. When pressure in the circuit increases over the set pressure of the relief valve due to pressurized oil (a) flowing from the HST charging pump, poppet (1) is opened and pressurized oil flows to hydraulic oil tank (b).

T4FJ-03-01-014 a-

From HST Charging Pump

Poppet

T3-1-22

To Hydraulic Oil Tank

SECTION 3 COMPONENT OPERATION Group 1 Pump Device HST Charging Pump 2

The HST charging pump is coaxially connected to the shaft of the HST pump. When the engine runs, the HST charging pump rotates with the HST pump together.

The HST charging pump is an internal gear pump. Inner rotor (1) and outer rotor (3) rotate together by engaging so that hydraulic oil is drawn to chamber A (4) and delivered from chamber B (2).

4 T4FC-03-08-100

12-

T3-1-23

Inner Rotor Chamber B

34-

Outer Rotor Chamber A

SECTION 3 COMPONENT OPERATION Group 1 Pump Device Main Pump, Brake/Transmission Pump 2

The engine output power is transmitted to shaft (1) of main pump (6) and shaft (3) of brake/transmission pump (5) in sequence through shaft (a) of the HST pump. When shafts (1, 3) rotate, main pump (6) and brake/ transmission pump (5) are activated simultaneously.

Main pump (6) and brake/ transmission pump (5) are gear pumps. When shafts (1, 3) rotate, drive gear (2) rotates. Therefore, driven gear (4) is rotated. Pressurized oil from suction port (b) fills the spaces between gears, flows along the inner surfaces of housing (7), and delivers through delivery port (c).

4 T487-03-01-006

4 5

T4FJ-03-01-015

Shaft (a) of HST Pump

Suction

Delivery

12-

Shaft Drive Gear

34-

Shaft Driven Gear

56-

Brake/ Transmission Pump Main Pump

T3-1-24

Housing

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Outline (Manually Operated Type) The control valve controls the pressure, flow rate, and flow direction in the hydraulic circuit. The major parts are the main relief valve, overload relief valve, and spools. The spool is operated manually by the cable.

Control Valve Overview a

Machine Front Side

Machine Left Side

Bucket

Lift Arm

T3-2-1

T4FJ-01-02-015

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Control Valve Hydraulic Diagram

5 2

T3-2-2

T4FJ-03-02-001

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Layout of Control Valve

1 2

Load Check Valve (Lift Arm Circuit)

Overload Relief Valve (Bucket: Rod Side)

34-

T3-2-3

Load Check Valve (Bucket Circuit) Main Relief Valve

56-

Bucket Spool Lift Arm Spool

T4FJ-03-02-002

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Hydraulic Circuit Main Circuit Pressurized oil from main pump (10) flows to hydraulic oil tank (9) through neutral circuit (11). Parallel circuit (12) is provided in the main circuit and makes the combined operation possible. Main relief valve (4) is provided in the main circuit (between pump and actuator). Main relief valve (4) prevents the pressure in main circuit from exceeding the set pressure when the spool is operated (or when the control lever is operated). Overload relief valve (2) is provided in the bucket circuit (between control valve and bucket cylinder (7)). Overload relief valve (2) prevents surge pressure caused by external force in the bucket circuit from exceeding the set pressure when bucket spool (5) is in neutral (with the control lever set in neutral). The spool in the control valve is operated by operating the control lever.

NOTE: Lift arm spool (6) in the lift arm circuit has two stage functions. First stage function is lift arm lower (a) and second stage function is lift arm float (b).

T3-2-4

SECTION 3 COMPONENT OPERATION Group 2 Control Valve

8 a

7 5 2

4 10

Lift Arm Lower

Lift Arm Float

Overload Relief Valve (Bucket Circuit) Main Relief Valve

567-

Bucket Spool Lift Arm Spool Bucket Cylinder

8- Lift Arm Cylinder 9- Hydraulic Oil Tank 10- Main Pump

T3-2-5

T4FJ-03-02-001

11- Neutral Circuit 12- Parallel Circuit

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Main Relief Valve The main relief valve prevents the pressure in the main circuit from exceeding the set pressure when the actuator such as the cylinder is operated. Therefore, oil leak from hose and pipe joints and breakage of the actuator are prevented.

Relief Operation 1. Pressure in port HP (main circuit) is routed to pilot poppet (7) through orifice A (2) in main poppet (1) and orifice B (3) in seat (4). 2. When pressure in port HP reaches the set pressure of spring B (6), pilot poppet (7) is opened, pressurized oil from passage A (5) flows to port LP (hydraulic oil tank) through the external circumference of sleeve (10). 3. At this time, a pressure difference is caused between port HP and spring chamber (9) due to orifice A (2). 4. When this pressure difference reaches the set pressure of spring A (8), main poppet (1) is opened and pressurized oil from port HP flows to port LP. 5. Consequently, the main circuit pressure decreases. 6. When the main circuit pressure decreases to the specified pressure, main poppet (1) is closed by the force of spring A (8).

T3-2-6

SECTION 3 COMPONENT OPERATION Group 2 Control Valve During Normal Operation: 1

T145-02-03-001

During Relief Operation:

T4FJ-03-02-003

HP- Main Circuit

LP- Hydraulic Oil Tank

123-

456-

Main Poppet Orifice A Orifice B

Seat Passage A Spring B

789-

T3-2-7

Pilot Poppet Spring A Spring Chamber

10- Sleeve

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Overload Relief Valve (Bucket: Rod Side) The overload relief valve is provided in the bucket rod side circuit. The overload relief valve prevents the bucket circuit pressure from rising excessively when the bucket is moved by external force. In addition, when the bucket circuit pressure decreases, the overload relief valve draws pressurized oil from the hydraulic oil tank and prevents the occurrence of cavitation (make-up function).

Relief Operation 1. Pressure in port HP (actuator circuit) is routed to pilot poppet (8) through orifice (1) of piston (3). 2. When pressure in port HP reaches the set pressure of spring B (6), pilot poppet (8) is opened, pressurized oil from passage A (5) flows to port LP (hydraulic oil tank) through the external circumference of sleeve (10). 3. At this time, a pressure difference occurs between port HP and spring chamber (9) due to orifice (1). 4. When this pressure difference reaches the set pressure of spring A (4), piston (3) and main poppet (2) are opened and pressurized oil from port HP flows to port LP. 5. Consequently, the actuator circuit pressure decreases. 6. When the actuator circuit pressure decreases to the specified pressure, piston (3) and main poppet (2) are closed by the force of spring A (4).

T3-2-8

SECTION 3 COMPONENT OPERATION Group 2 Control Valve During Normal Operation: 2

T4GB-03-02-030

During Relief Operation: 2

HP- Actuator Circuit

LP- Hydraulic Oil Tank

123-

456-

Orifice Main Poppet Piston

Spring A Passage A Spring B

T4GB-03-02-031

789-

T3-2-9

Spring C Pilot Poppet Spring Chamber

10- Sleeve

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Make-Up Operation 1. When pressure in port HP (actuator circuit) decreases lower than pressure in port LP (hydraulic oil tank), sleeve (10) is moved to the right. 2. Hydraulic oil in port LP flows to port HP and cavitation is prevented. 3. When pressure in port HP increases to the specified pressure, sleeve (10) is closed by the force of spring C (7).

T3-2-10

SECTION 3 COMPONENT OPERATION Group 2 Control Valve During Make-Up Operation: 10

7 T4GB-03-02-032

HP- Actuator Circuit

LP- Hydraulic Oil Tank

10- Sleeve

Spring C

T3-2-11

SECTION 3 COMPONENT OPERATION Group 2 Control Valve (Blank)

T3-2-12

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Outline (Hydraulic Operated Type) (Option) The control valve controls the pressure, flow rate, and flow direction in the hydraulic circuit. The major parts are the main relief valve, overload relief valve, and spools. The spools are operated by the pilot oil pressure.

Control Valve Overview

1 TNCC-03-02-001

b a-

Machine Front Side

Machine Left Side

Bucket

Lift Arm

T3-2-13

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Control Valve Hydraulic Diagram

6 1

T3-2-14

TNCC-03-02-002

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Layout of Control Valve

7 4

TNCC-03-02-001

TNCC-03-02-003

12-

Load Check Valve (Lift Arm Circuit) Overload Relief Valve (Bucket: Rod Side)

3456-

Load Check Valve (Bucket Circuit) Main Relief Valve Bucket Spool Lift Arm Spool

78-

T3-2-15

Overload Relief Valve (Bucket: Bottom Side) Make-Up Valve (Lift Arm: Rod Side)

Overload Relief Valve (Lift Arm: Bottom Side)

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Hydraulic Circuit Main Circuit Pressurized oil from main pump (12) flows to hydraulic oil tank (13) through neutral circuit (11). Parallel circuit (10) is provided in the main circuit and makes the combined operation possible. Main relief valve (4) is provided in the main circuit (between pump and actuator). Main relief valve (4) prevents the pressure in main circuit from exceeding the set pressure when the spool is operated (or when the control lever is operated). Overload relief valves (2, 7, 9) are provided in the actuator circuits (between control valve and actuator) of lift arm cylinder (15) bottom side and bucket cylinder (14). Overload relief valves (2, 7, 9) prevent the surge pressure caused by external force in the actuator circuit from exceeding the set pressure when the spool is in neutral (with the control lever set in neutral). Make-up valve (8) is provided in the actuator circuit (between control valve and actuator) of lift arm cylinder (15) rod side. Make-up valve (8) draws pressurized oil from hydraulic oil tank (13) and prevents cavitation from occurring when the pressure in the actuator circuit decreases.

T3-2-16

SECTION 3 COMPONENT OPERATION Group 2 Control Valve

6 1

11 5

123-

Load Check Valve (Lift Arm Circuit) Overload Relief Valve (Bucket: Rod Side) Load Check Valve (Bucket Circuit)

4567-

Main Relief Valve Bucket Spool Lift Arm Spool Overload Relief Valve (Bucket: Bottom Side)

Make-Up Valve (Lift Arm: Rod Side) 9- Overload Relief Valve (Lift Arm: Bottom Side) 10- Parallel Circuit 11- Neutral Circuit

T3-2-17

12131415-

TNCC-03-02-002

Main Pump Hydraulic Oil Tank Bucket Cylinder Lift Arm Cylinder

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Pilot Operation Control Circuit Pressurized oil from the pilot valve acts on the spool in the control valve in order to move the spool. x During bucket dump (Pia1) operation, pressurized oil moves bucket spool (5). x During lift arm lower (Pia2) operation, pressurized oil moves lift arm spool (6).

NOTE: Lift arm spool (6) has two stage functions. First stage function is lift arm lower (a) and second stage function is lift arm float (b).

T3-2-18

SECTION 3 COMPONENT OPERATION Group 2 Control Valve

P2 Pia1

Pib1

Pib2

Pia2

Pib2

Pia2

Pib1

Pia1

TNCC-03-02-004

Pia1- Bucket Dump

Pib1- Bucket Rollback

Lift Arm Lower

Lift Arm Float

12-

Bucket Pilot Valve Lift Arm Pilot Valve

34-

Pilot Pump Control Valve

Pia2- Lift Arm Lower

56-

T3-2-19

Bucket Spool Lift Arm Spool

Pib2- Lift Arm Raise

T3-2-20

SECTION 3 COMPONENT OPERATION Group 2 Control Valve During Normal Operation: 1

T145-02-03-001

During Relief Operation:

T4FJ-03-02-003

HP- Main Circuit

LP- Hydraulic Oil Tank

123-

456-

Main Poppet Orifice A Orifice B

Seat Passage A Spring B

789-

T3-2-21

Pilot Poppet Spring A Spring Chamber

10- Sleeve

SECTION 3 COMPONENT OPERATION Group 2 Control Valve Overload Relief Valve The overload relief valve is located in the lift arm raise and bucket circuits. The overload relief valve prevents each actuator circuit pressure from rising excessively when the actuators are moved by external force. In addition, when the actuator circuit pressure decreases, the overload relief valve draws pressurized oil from the hydraulic oil tank and prevents the occurrence of cavitation (make-up function).

T3-2-22

SECTION 3 COMPONENT OPERATION Group 2 Control Valve During Normal Operation: 2

T4GB-03-02-030

During Relief Operation: 2

HP- Actuator Circuit

LP- Hydraulic Oil Tank

123-

456-

Orifice Main Poppet Piston

Spring A Passage A Spring B

T4GB-03-02-031

789-

T3-2-23

Spring C Pilot Poppet Spring Chamber

10- Sleeve

T3-2-24

SECTION 3 COMPONENT OPERATION Group 2 Control Valve During Make-Up Operation: 10

7 T4GB-03-02-032

HP- Actuator Circuit

LP- Hydraulic Oil Tank

10- Sleeve

Spring C

T3-2-25

SECTION 3 COMPONENT OPERATION Group 2 Control Valve (Blank)

T3-2-26

SECTION 3 COMPONENT OPERATION Group 3 Priority Valve Outline The priority valve consists of relief valve (1), spool (3), spring (2), orifice A (4), orifice B (5), and orifice C (6).

Relief valve (1) is provided in the priority valve. Relief valve (1) prevents the circuit pressure between priority valve and steering valve (c) from increasing beyond the set pressure when the steering cylinder is at the stroke end.

The priority valve delivers pressurized oil (a) from the main pump to steering valve (c) and control valve (b) according to the steering valve (c) operation.

a 1

Pressurized Oil from Main Pump To Control Valve

c- To Steering Valve P- Port P CF- Port CF

EF- Port EF LS- Port LS T- Port T

12-

Relief Valve Spring

34-

Spool Orifice A

T3-3-1

Orifice B

TNCC-03-03-005

Orifice C

SECTION 3 COMPONENT OPERATION Group 3 Priority Valve Operation When steering is in neutral 1. Pressurized oil (a) from the main pump flows to port P and is divided into three directions in the inner passage of spool (3). 2. When steering valve (10) is in neutral (the steering wheel is not operated), pressurized oil flowing from port CF is blocked by steering valve (10) so that pressure in port CF increases. 3. As pressure in port CF increases, pressurized oil (a) from the main pump flows to chamber A (7) and chamber B (8) through orifice A (4) and orifice B (5) respectively. 4. As pressurized oil in chamber B (8) flows to the hydraulic oil tank through port LS and steering valve (10), pressure in chamber B (8) becomes lower than pressure in chamber A (7) due to orifice B (5). 5. When the pressure difference overcomes the spring (2) force, spool (3) moves to the left. 6. Therefore, pressurized oil (a) from the main pump flows to control valve (b) through port EF.

T3-3-2

SECTION 3 COMPONENT OPERATION Group 3 Priority Valve

LS 8 5 2 EF

a P

TNCC-03-03-001

Pressurized Oil from Main Pump

bP-

To Control Valve Port P

CF- Port CF EF- Port EF

123-

Relief Valve Spring Spool

456-

Orifice A Orifice B Orifice C

7- Chamber A 8- Chamber B 10- Steering Valve

T3-3-3

LS- Port LS T- Port T

SECTION 3 COMPONENT OPERATION Group 3 Priority Valve When steering is operated IMPORTANT: Orifice D (15) of steering valve (10) is a variable orifice and the opening area of it is changed in proportion to the rotating speed of steering wheel (11). 1. When steering wheel (11) is rotated, spool (13) of steering valve (10) moves and orifice D (15) is opened. 2. Pressurized oil in the circuit between chamber A (7) and port CF in the priority valve and orifice D (15) in steering valve (10) flows to gerotor (12). 3. When pressurized oil flows to gerotor (12), the pressure in the circuit between chamber A (7) and port CF in the priority valve and orifice D (15) in steering valve (10) decreases. Then, spool (3) in the priority valve is moved to the right by the spring (2) force. 4. Spool (3) in the priority valve becomes balanced at the position where pressurized oil flow rate corresponds to the open amount of orifice D (15). 5. At this time, pressurized oil (a) from the main pump flows to steering valve (10) and control valve (b) through spool (3) in the priority valve. 6. Pressurized oil (a) from the main pump flows to gerotor (12) through spool (13) and sleeve (14) in steering valve (10). 7. Gerotor (12) delivers pressurized oil as a hydraulic motor. This pressurized oil flows to steering cylinder (16) and the machine turns.

T3-3-4

SECTION 3 COMPONENT OPERATION Group 3 Priority Valve

12 14 15 11 13 14

a P

T 7

b TNCC-03-03-002

Pressurized Oil from Main Pump

bP-

To Control Valve Port P

CF- Port CF EF- Port EF

LS- Port LS T- Port T

237-

Spring Spool Chamber A

10- Steering Valve 11- Steering Wheel 12- Gerotor

13- Spool 14- Sleeve 15- Orifice D

16- Steering Cylinder

T3-3-5

SECTION 3 COMPONENT OPERATION Group 3 Priority Valve When steering cylinder is at stroke end IMPORTANT: Relief valve (1) prevents the circuit pressure between priority valve and steering valve (10) from increasing beyond the set pressure when steering cylinder (16) is at the stroke end.

1. Pressurized oil flowing to port P in steering valve (10) is divided inside spool (13). One flows to gerotor (12). The other flows to port LS in the priority valve and is routed to chamber B (8) through orifice C (6). 2. When steering cylinder (16) reaches the stroke end, the pressure at port P increases and the pressure in chamber B (8) in the priority valve also increases due to the pressure through port LS. 3. When pressure in chamber B (8) increases beyond the set pressure, poppet (9) of relief valve (1) in the priority valve is opened and pressurized oil routed to chamber B (8) flows to hydraulic oil tank (17) through relief valve (1). 4. As pressurized oil in chamber B (8) flows to hydraulic oil tank (17) when poppet (9) of relief valve (1) is opened, the pressure difference between chamber A (7) and chamber B (8) occurs due to orifice B (5). 5. When the pressure difference overcomes the spring (2) force, spool (3) in the priority valve moves to the left. 6. Pressurized oil (a) from the main pump flows to control valve (b) through spool (3) in the priority valve and port EF. 7. Therefore, when steering cylinder (16) is at the stroke end, pressurized oil flows to control valve (b).

T3-3-6

SECTION 3 COMPONENT OPERATION Group 3 Priority Valve

10 12 13

9 3

a P

17 EF 6 8

b TNCC-03-03-003

Pressurized Oil from Main Pump

bP-

To Control Valve Port P

CF- Port CF EF- Port EF

LS- Port LS T- Port T

1235-

Relief Valve Spring Spool Orifice B

6789-

Orifice C Chamber A Chamber B Poppet

10111213-

16- Steering Cylinder 17- Hydraulic Oil Tank

T3-3-7

Steering Valve Steering Wheel Gerotor Spool

SECTION 3 COMPONENT OPERATION Group 3 Priority Valve (Blank)

T3-3-8

SECTION 3 COMPONENT OPERATION Group 4 Steering Valve Outline The steering valve is located between the priority valve and the steering cylinder. The steering valve supplies pressurized oil from the main pump to the steering cylinder through the priority valve in response to the movement of the steering wheel. (Refer to SYSTEM / Hydraulic System / Steering Circuit.)

T4FC-03-04-001

Steering Wheel

12-

Port L (for Steering (Left)) Port R (for Steering (Right))

34-

Port P (from Priority Valve) Port T (to Hydraulic Oil Tank)

T3-4-1

Port LS

SECTION 3 COMPONENT OPERATION Group 4 Steering Valve 11

Structure

The steering valve consists of gerotor (8), drive (7), sleeve (3), spool (4), pin (5), housing (1), centering springs (2), and others. When the steering wheel is rotated, spool (4) rotates and an oil passage is generated between spool (4) and sleeve (3). Pressurized oil from the main pump is controlled by spool (4) and sleeve (3), and flows to the steering cylinder. Centering springs (2) are arranged in both spool (4) and sleeve (3), and return sleeve (3) to the neutral position when the steering handle operation is stopped.

T4FC-03-04-007

2 5 4

2 3 1

12 5

10 9

6 T4FC-03-04-002 1234-

Housing Centering Spring Sleeve Spool

5678-

Pin Plate Drive Gerotor

9101112-

T3-4-2

Spacer Cap Check Valve Hole

13- Load Check Valve

SECTION 3 COMPONENT OPERATION Group 4 Steering Valve Operation Sleeve (3), spool (4), and drive (7) are mutually connected by pin (5). L

When the steering wheel (spool (4)) is rotated, a relative angular difference arises between sleeve (3) and spool (4) as hole (12) of spool (4) is a elongate hole. 7

The movement of the steering wheel is transmitted only to spool (4), and port P (from the main pump) is connected to port R (to the steering cylinder (right)) or port L (to the steering cylinder (left)) through sleeve (3) and spool (4).

3 4

a T

T4FJ-03-04-002

T4FC-03-04-003

Steering Wheel

T3-4-3

SECTION 3 COMPONENT OPERATION Group 4 Steering Valve Steering (Left) 1. When the steering wheel is rotated left, spool (4) rotates via shaft (16), and pressurized oil from main pump (15) flows in the order of port P - sleeve (3) spool (4) - sleeve (3) - housing (1) - gerotor (8).

4. When pressurized oil from main pump (15) enters gerotor (8), gerotor (8) rotates left. The rotation of gerotor (8) is transmitted to sleeve (3) through drive (7) and sleeve (3) rotates left similarly.

2. Pressurized oil from gerotor (8) flows in the order of housing (1) - sleeve (3) - spool (4) - sleeve (3) - port L - steering cylinder (13). Then, it moves steering cylinder (13) and directs the machine to the left.

5. When sleeve (3) rotates the same amount of turns as spool (4), the passages of sleeve (3) and spool (4) are closed and operation of steering cylinder (13) is stopped.

3. Returning oil from steering cylinder (13) enters port R, flows in the order of housing (1) - sleeve (3) - spool (4) - sleeve (3) - port T, and returns to the hydraulic oil tank.

6. Therefore, gerotor (8) rotates in response to the rotation of the steering wheel and steering cylinder (13) is operated in response to the amount of turns of the steering wheel.

15 1 8 7

16 123-

Housing Centering Spring Sleeve

478-

Spool Drive Gerotor

TNCC-03-03-004

3 13- Steering Cylinder 14- Steering Valve 15- Main Pump

T3-4-4

16- Shaft

SECTION 3 COMPONENT OPERATION Group 4 Steering Valve Steering (Right) T

1. When the steering wheel is rotated right, pressurized oil from the main pump flows in the order of port P - port R - steering cylinder, moves the steering cylinder, and directs the machine to the right.

2. Returning oil from the steering cylinder flows in the order of port L - port T and returns to the hydraulic oil tank.

TNDB-03-04-010

Neutral

1. When the steering wheel is not rotated, pressurized oil from the main pump is blocked by spool (4) and does not flow to the steering cylinder. 2. Therefore, the steering cylinder is not operated.

T3-4-5

TNDB-03-04-011

SECTION 3 COMPONENT OPERATION Group 4 Steering Valve (Blank)

T3-4-6

SECTION 3 COMPONENT OPERATION Group 5 HST Motor Outline The HST motor consists of travel motor (1), regulator (4), displacement angle control solenoid valve (5), travel control solenoid valve (9), and flushing valve (3). Travel motor (1) is a bent-axis type variable displacement axial plunger motor. Travel motor (1) is driven by pressurized oil from the HST pump and transmits the rotation power to the transmission. Regulator (4) regulates the displacement angle of travel motor (1) due to pressurized oil from displacement angle control solenoid valve (5) or travel control solenoid valve (9). Flushing valve (3) releases hydraulic oil in the lowpressure side to the drain circuit and exchanges hydraulic oil in the HST circuit.

7, 8 (Opposite Side)

9 b

5 TNCC-03-05-001

Machine Front Side

Machine Upper Side

123-

Travel Motor Port T1 Flushing Valve

45-

Regulator Displacement Angle Control Solenoid Valve

67-

T3-5-1

Port T2 Port B

89-

Port A Travel Control Solenoid Valve

SECTION 3 COMPONENT OPERATION Group 5 HST Motor HST Motor Hydraulic Diagram 2

1 T1

4 T4FC-03-09-005

HST Motor Layout b

3 TNCC-03-05-001

A-

Port A

B-

Port B

Port T1

T2- Port T2

123-

Regulator Travel Control Solenoid Valve Displacement Angle Control Solenoid Valve Flushing Valve

56789-

Shaft Plunger Cylinder Block Valve Plate Control Rod

1011121314-

Spring Center Pin Bearing Spring Spool

15161718-

T3-5-2

Spring (2 Used) Spring Plunger Spool

SECTION 3 COMPONENT OPERATION Group 5 HST Motor Rotary Group Part: 7

12 11 9

T4FC-03-09-006

Travel Control Solenoid Valve:

Flushing Valve: 17 16 4 2

15 15

14 T4FC-03-09-009 View a

T4FC-03-09-010

Section b-b

1234-

Regulator Travel Control Solenoid Valve Displacement Angle Control Solenoid Valve Flushing Valve

56789-

Shaft Plunger Cylinder Block Valve Plate Control Rod

1011121314-

T3-5-3

Spring Center Pin Bearing Spring Spool

15161718-

Spring (2 Used) Spring Plunger Spool

SECTION 3 COMPONENT OPERATION Group 5 HST Motor Travel Motor The travel motor is a bent-axis type variable displacement axial plunger motor. The travel motor consists of valve plate (8), cylinder block (7), plunger (6), and shaft (5). Shaft (5) and cylinder block (7) are connected by plunger (6).

When pressurized oil is supplied from the HST pump, plunger (6) reciprocates in the cylinder block (7) bore and cylinder block (7) slides on valve plate (8). Then, shaft (5) rotates.

T4FC-03-09-006

Shaft

Plunger

T3-5-4

Cylinder Block

Valve Plate

SECTION 3 COMPONENT OPERATION Group 5 HST Motor Regulator 1

The regulator consists of servo piston (2), servo pin (3), balance spring (4), spring (5), and spool (6). Servo piston (2) is connected to valve plate (1) in the travel motor through servo pin (3). The displacement angle of valve plate (1) and the cylinder block is changed according to the movement of servo piston (2). Therefore, the rotation speed of the travel motor is controlled.

2 3

T4FC-03-09-003

Displacement Angle Control Solenoid Valve Displacement angle control solenoid valve (7) is a proportional solenoid valve. Displacement angle control solenoid valve (7) controls servo piston (2) in the regulator according to the signal from MC. When MC sends maximum current value (F), it makes the displacement angle of the travel motor maximum. When MC sends minimum current value (D), it makes the displacement angle of the travel motor minimum.

C F

ABCD-

12-

Valve Plate Servo Piston

34-

Servo Pin Balance Spring

56-

T3-5-5

Maximum Displacement Travel Motor Displacement Angle Minimum Displacement Minimum Current Value

Spring Spool

EF-

Command Current Maximum Current Value

Displacement Angle Control Solenoid Valve

SECTION 3 COMPONENT OPERATION Group 5 HST Motor Motor Displacement Angle Control Displacement Angle Control (From Large Displacement Angle to Small Displacement Angle) 1

1. One pressurized oil from port B (or port A) flows to the plunger through the valve plate. The other pressurized oil pushes to open check valve (4) and flows to the small chamber (7) side of servo piston (5) through piston (6).

2 a

3 6

2. When MC sends signal (a) to displacement angle control solenoid valve (2), spool (3) moves upward. Pressurized oil in the large chamber (8) side of servo piston (5) flows to the hydraulic oil tank through spool (3).

3. Therefore, servo piston (5) moves downward and the travel motor displacement angle decreases. 5

4. Consequently, the travel motor rotates at fast speed. 7

NOTE: The illustration shows the circuit while driving in forward direction.

A b

8 TNCC-03-05-002 AB-

Port A Port B

ab-

Signal from MC Travel Motor Operating Pressure

12-

Travel Control Solenoid Valve Displacement Angle Control Solenoid Valve Spool Check Valve

5678-

Servo Piston Piston Small Chamber Large Chamber

34-

T3-5-6

SECTION 3 COMPONENT OPERATION Group 5 HST Motor Displacement Angle Control (From Small Displacement Angle to Large Displacement Angle) 1. One pressurized oil from port B (or port A) flows to the plunger through the valve plate. The other pressurized oil pushes to open check valve (4) and flows to the small chamber (7) side of servo piston (5) through spool (6).

3 6

2. When MC sends signal (a) to displacement angle control solenoid valve (2), spool (3) is pushed down. Pressurized oil from port B (or port A) flows to the large chamber (8) side of servo piston (5) through spool (3).

7 4

3. As the pressure receiving area in the large chamber (8) side of servo piston (5) is larger than that in the small chamber (7) side, servo piston (5) moves upward to the position where servo piston (5) balances with balance spring (9) so that the travel motor displacement angle increases.

4. Consequently, the travel motor rotates at slow speed.

A b

NOTE: The illustration shows the circuit while driving in forward direction. 8 TNCC-03-05-003 AB-

Port A Port B

ab-

Signal from MC Travel Motor Operating Pressure

12-

Travel Control Solenoid Valve Displacement Angle Control Solenoid Valve Spool Check Valve

56789-

Servo Piston Spool Small Chamber Large Chamber Balance Spring

34-

T3-5-7

SECTION 3 COMPONENT OPERATION Group 5 HST Motor Travel Control Solenoid Valve 1

Travel control solenoid valve (1) decreases the HST braking power when decelerating from fast speed and prevents travel speed from decelerating immediately. (Refer to SYSTEM / Control System / Travel Immediate Slowdown Prevention Control.) Travel control solenoid valve (1) is an ON/OFF solenoid valve and is shifted by signal (a) from MC.

2 T4FC-03-09-009

y While driving in forward direction:

1. When the forward/reverse lever is in the forward position, travel control solenoid valve (1) is turned OFF by signal (a) from MC. Piston (2) is moved up by the spring (3) force.

2 6

2. The circuit pressure in the port A side is higher than that in the port B side while driving in forward direction.

3. When the accelerator pedal is released (the accelerator is shifted to OFF from ON), the circuit pressure in the port B side is temporarily high. At this time, one circuit pressure in the port B side pushes to open check valve (5) and is blocked by piston (2) of travel control solenoid valve (1).

4 7 b

4. Therefore, the travel motor displacement angle increase is limited temporarily. (Refer to Displacement Angle Control (From Small Displacement Angle to Large Displacement Angle).) 5. Consequently, when the accelerator pedal is released (the accelerator is shifted to OFF from ON) while driving in forward direction, travel speed is prevented from decelerating immediately.

TNCC-03-05-004

AB-

Port A Port B

ab-

Signal from MC Travel Motor Operating Pressure

1234-

Travel Control Solenoid Valve Piston Spring Servo Piston

567-

Check Valve Check Valve Small Chamber

NOTE: When the forward/reverse lever is shifted from forward to neutral position, it functions in the same way.

T3-5-8

SECTION 3 COMPONENT OPERATION Group 5 HST Motor y While driving in reverse direction: 1. When the forward/reverse lever is in the reverse position, travel control solenoid valve (1) is turned ON by signal (a) from MC. Piston (2) is moved down.

2. The circuit pressure in the port B side is higher than that in the port A side while driving in reverse direction.

6 5

3. When the accelerator pedal is released (the accelerator is shifted to OFF from ON), the circuit pressure in the port A side is temporarily high. At this time, one circuit pressure in the port A side pushes to open check valve (6) and is blocked by piston (2) of travel control solenoid valve (1).

4 5

4. Therefore, the travel motor displacement angle increase is limited temporarily. (Refer to Displacement Angle Control (From Small Displacement Angle to Large Displacement Angle).) 5. Consequently, when the accelerator pedal is released (the accelerator is shifted to OFF from ON) while driving in reverse direction, travel speed is prevented from decelerating immediately.

TNCC-03-05-005

AB-

Port A Port B

ab-

Signal from MC Travel Motor Operating Pressure

1234-

Travel Control Solenoid Valve Piston Spring Servo Piston

567-

Check Valve Check Valve Small Chamber

T3-5-9

SECTION 3 COMPONENT OPERATION Group 5 HST Motor Flushing Valve Flushing valve (5) receives both high pressure in the HST circuit (motor operating pressure from the HST pump) and low pressure (circuit pressure returned from the HST motor). Then, it releases hydraulic oil in the low-pressure side to the drain circuit and exchanges hydraulic oil in the HST circuit. Pressurized oil in the port A side and pressurized oil in the port B side are routed to spool (3) of flushing valve (5) respectively. When motor operating pressure (high pressure) from the HST pump is routed to port B (or port A), it is also routed to spool (3) of flushing valve (5) and overcomes the spring (2) force. Therefore, spool (3) moves to the right (or left) and the circuit (low pressure) returned from the HST motor is connected to the drain circuit through port T2. Consequently, hydraulic oil in the HST circuit flows to the drain circuit.

T3-5-10

3 T4FC-03-09-010

SECTION 3 COMPONENT OPERATION Group 5 HST Motor

2 1

3 T4FC-03-09-013

A-

Port A

B-

Port B

T2- Port T2

12-

Spring Spring

Spring

NOTE: The illustration shows the circuit when motor operating pressure (high pressure) is routed to the port B side.

T3-5-11

Motor

Flushing Valve

SECTION 3 COMPONENT OPERATION Group 5 HST Motor (Blank)

T3-5-12

SECTION 3 COMPONENT OPERATION Group 6 Transmission Outline The transmission consists of input shaft (1), fast-speed clutch (3), fast-speed drive gear (2), slow-speed drive gear (11), slow-speed clutch (8), parking brake (12), and output shaft (15). The transmission converts diving power (a) from the HST motor into either fast speed or slow speed and transmits it to the front and rear axles through propeller shafts (b, c).

4, 5

9, 10 11

13 T4FJ-03-06-001

HST Motor Driving Power

Propeller Shaft (Front)

Propeller Shaft (Rear)

1234-

Input Shaft Fast-Speed Drive Gear Fast-Speed Clutch Drive Plate

5678-

Clutch Disc Piston Piston Slow-Speed Clutch

9101112-

Drive Plate Clutch Disc Slow-Speed Drive Gear Parking Brake

T3-6-1

13- Slow-Speed Driven Gear 14- Fast-Speed Driven Gear 15- Output Shaft

SECTION 3 COMPONENT OPERATION Group 6 Transmission Operation When fast speed mode is selected: 1. When the shift switch is set to the Hi position, pressurized oil (P) is delivered to fast-speed clutch (3). (Refer to SYSTEM / Hydraulic System.)

3. When fast-speed clutch (3) is engaged, input shaft (1) is connected to fast-speed drive gear (2). 4. Fast-speed driven gear (14) is connected to output shaft (15) by a spline joint. The output power of the HST motor is transmitted to input shaft (1), fastspeed drive gear (2), fast-speed driven gear (14), and output shaft (15) in sequence. Then, output shaft (15) rotates at fast speed.

2. When pressurized oil (P) is delivered, piston (6) is moved to the left and pushes drive plates (4) and clutch discs (5) so that fast-speed clutch (3) is engaged.

14 T4FJ-03-06-002

P-

Pressurized Oil

12-

Input Shaft Fast-Speed Drive Gear

34-

Fast-Speed Clutch Drive Plate

56-

T3-6-2

Clutch Disc Piston

14- Fast-Speed Driven Gear 15- Output Shaft

SECTION 3 COMPONENT OPERATION Group 6 Transmission When slow speed mode is selected: 1. When the shift switch is set to the Lo position, pressurized oil (P) is delivered to slow-speed clutch (8).(Refer to SYSTEM / Hydraulic System.)

3. When slow-speed clutch (8) is engaged, input shaft (1) is connected to slow-speed drive gear (11). 4. Slow-speed driven gear (13) is connected to output shaft (15) by a spline joint. The output power of the HST motor is transmitted to input shaft (1), slowspeed drive gear (11), slow-speed driven gear (13), and output shaft (15) in sequence. Then, output shaft (15) rotates at slow speed.

2. When pressurized oil (P) is delivered, piston (7) is moved to the right and pushes drive plates (9) and clutch discs (10) so that slow-speed clutch (8) is engaged.

11 1

13 T4FJ-03-06-003

P-

Pressurized Oil

17-

Input Shaft Piston

89-

Slow-Speed Clutch Drive Plate

10- Clutch Disc 11- Slow-Speed Drive Gear

T3-6-3

13- Slow-Speed Driven Gear 15- Output Shaft

SECTION 3 COMPONENT OPERATION Group 6 Transmission Parking Brake The parking brake is a wet-type spring set hydraulic released multi-disc brake. When the brake release pressure is routed to brake piston chamber (4), the brake is released. Friction plates (1) and plates (3) are connected to housing (2) in the parking brake and output shaft (15) by a spline joint respectively.

When brake is released 1. When the parking brake switch is set to the OFF position, the parking brake solenoid valve is activated so that pressurized oil (a) from the brake/ transmission pump is routed to brake piston (4) through the parking brake solenoid valve. 2. Consequently, as brake piston (4) is pushed, plates (3) and friction plates (1) become freed each other so that the brake is released.

3 a 4 5

6 T4FJ-03-06-005

Pressurized Oil from Brake/ Transmission Pump

To Oil Pan

12-

Friction Plate Housing

Plate

T3-6-4

Brake Piston

56-

Output Shaft Spring

SECTION 3 COMPONENT OPERATION Group 6 Transmission When brake is applied 1. When the parking brake switch is set to the ON or neutral position, the parking brake solenoid valve stops. 2. As pressurized oil routed to brake piston (4) returns to oil pan (b) of the transmission through the spool of the parking brake solenoid valve, brake piston (4) is pushed back by spring (6). 3. Consequently, the spring (6) force acts on plate (3), which is engaged with the external circumference of output shaft (5), and on friction plate (1), which is engaged with the inside of parking brake housing (2) through brake piston (4). Therefore, the external circumference of output shaft (5) is secured with friction force.

3 b 4 5

6 T4FJ-03-06-004

Pressurized Oil from Brake/ Transmission Pump

To Oil Pan

12-

Friction Plate Housing

Plate

T3-6-5

Brake Piston

56-

Output Shaft Spring

SECTION 3 COMPONENT OPERATION Group 6 Transmission Travel Mode Selector Valve Travel mode selector valve (1) supplies pressurized oil (a) from the brake/transmission pump to the crutch and shifts fast and slow travel speeds.

T4FJ-03-06-006

At Fast Speed:

When the shift switch is set to the Hi position, the travel mode selector solenoid valve is turned OFF. Pressurized oil (a) from the brake/transmission pump flows to fastspeed clutch (c) through spool (2) in travel mode selector valve (1).

T4FJ-03-06-007

At Slow Speed:

When the shift switch is set to the Lo position, the travel mode selector solenoid valve is turned ON. Pressurized oil (d) from travel mode selector valve (1) moves spool (2) in travel mode selector valve (1) to the right. Pressurized oil (a) from the brake/transmission pump flows to slow-speed clutch (e) through spool (2) in travel mode selector valve (1).

T4FJ-03-06-008

Pressurized Oil from Brake/ Transmission Pump To Fast-Speed Clutch

Pressurized Oil from Travel Mode Selector Solenoid Valve To Slow-Speed Clutch

Travel Mode Selector Valve

Spool

T3-6-6

SECTION 3 COMPONENT OPERATION Group 6 Transmission

8 a 6

7 TNCC-03-06-004

Pressurized Oil from Brake/ Transmission Pump

123-

Transmission Fast-Speed Clutch Slow-Speed Clutch

456-

Parking Brake Parking Brake Solenoid Valve Relief Valve

78-

T3-6-7

Oil Pan Accumulator

Travel Mode Selector Solenoid Valve 10- Travel Mode Selector Valve

SECTION 3 COMPONENT OPERATION Group 6 Transmission Accumulator P

1. Pressurized oil from the brake/ transmission pump is routed to the fast or slow-speed clutch piston through accumulator (1), the travel mode selector valve. (The procedures with the slow-speed clutch engaged are explained.) 2. Generally, piston (3) compresses spring (2) due to pressurized oil from the brake/ transmission pump and is moved to the left so that stopper (4) is kept. (Fig. B)

T4FJ-03-06-006

3. When shifting to slow speed from fast speed, pressurized oil flows to the slow-speed clutch side and pressure decreases.

4. Therefore, as pressure in chamber P of accumulator (1) becomes smaller than the spring (2) force, piston (3) is moved back by the spring (2) force and is moved to the right. (Fig. A) TNCC-03-06-002

5. When the slow-speed clutch starts operating, pressure increases.

6. As pressure in chamber P of accumulator (1) becomes larger than the spring (2) force, piston (3) compresses spring (2) and is moved to the left. (Fig. B)

7. The shock developed when engaging the slowspeed clutch is reduced due to the operation of piston (3).

12-

T3-6-8

Accumulator Spring

34-

Piston Stopper

TNCC-03-06-003

SECTION 3 COMPONENT OPERATION Group 6 Transmission Solenoid Valve The travel mode selector solenoid valve (2) for shifting travel speed and parking brake solenoid valve (1) for releasing the parking brake are provided.

Travel Mode Selector Solenoid Valve Travel mode selector solenoid valve (2) is an ON/OFF solenoid valve. It shifts the travel mode selector valve according to the signal from MC (Main Controller). (Refer to SYSTEM / Control System.)

Parking Brake Solenoid Valve Parking brake solenoid valve (1) is an ON/OFF solenoid valve. When the parking brake release function of the parking brake switch is selected, parking brake solenoid valve (1) is turned ON and the transmission parking brake is released. (Refer to SYSTEM / Electrical System.)

T4FJ-03-06-011 1-

T3-6-9

Parking Brake Solenoid Valve

Travel Mode Selector Solenoid Valve

SECTION 3 COMPONENT OPERATION Group 6 Transmission ON/OFF Solenoid Valve The ON / OFF solenoid valve shifts the parking brake switch and shift switch in order to shift pilot pressure. y When in neutral Spool (1) is pushed to the right by spring (2). Output port (A) is connected to tank port (T). y When operated: As solenoid (3) is activated, spool (1) is pushed to the left. Pilot port (P) is connected to output port (A) and tank port (T) is blocked.

TNCC-03-06-001

P-

Pilot Port

A-

Output Port

T-

Tank Port

Spool

Spring

Solenoid

T3-6-10

SECTION 3 COMPONENT OPERATION Group 7 Axle Outline Axle consists of differential (3), final drive (2), axle shaft (1), and brake (4).

Power from the transmission is transmitted to the front axle and the rear axle through the propeller shaft. Inside the axle, power is transmitted to differential (3). The power is divided into left and right by differential (3) and drives axle shaft (1) and the wheels through final drive (2).

View A

T4FJ-03-07-001

Axle Shaft

Final Drive

T3-7-1

Differential

Brake

SECTION 3 COMPONENT OPERATION Group 7 Axle Differential The differential enables the left and right drive wheels to rotate at different rotating speeds while steering and traveling on uneven surfaces.

9 10 11 12 13

7 8

14 15

2 1

17 18 19

20 T4FJ-03-07-002

123456-

Brake Disc End Plate Brake Ring Piston Side Gear Pinion Gear

789101112-

Case B Spider Ring Gear Case A Roller Bearing Differential Body

131415161718-

T3-7-2

Shaft Bearing Retainer Pinion Shaft Roller Bearing Bearing Cage Spacer

19- Roller Bearing 20- Oil Seal 21- Flange

SECTION 3 COMPONENT OPERATION Group 7 Axle Purpose of Differential 1. When the machine is steered, the inner wheel turns with a smaller radius, so the outer wheel needs to rotate faster for smooth steering. 2. Suppose driving the rear wheel by directly installing the gear to the propeller shaft with a shaft having no differential. 3. In this case, the outer wheel and the inner wheel rotate at the same rate. Therefore, when the machine is steered, the outer wheel cannot rotate more than the inner wheel. Consequently, axle strain, tire scuffing and wear takes place. In addition, due to axle shaft torsional stress and unstable transmission of drive force take place. 4. On the other hand, with a differential installed, the inner and the outer wheels can rotate at different speeds, and the problem mentioned above is eliminated.

b c T202-03-05-005 a-

Extension Line of Rear Wheel Centers

While Turning the Machine

T3-7-3

Traveling on Rough Surfaces

SECTION 3 COMPONENT OPERATION Group 7 Axle Principle of Differential Operation principle of the differential is explained here comparing it to the racks and the pinion gear in the drawing. W

1. When the load W is equally applied to rack A (1) and rack B (3), and if C is moved upward by the distance of H, rack A (1) and rack B (2) both move the same distance of H in unison with pinion (2).

W C

C H

2. If moved by removing the load from rack B (3), pinion (2) rotates on rack A (1) (with load applied) and moves upward.

3. Rack B (3) (with light load applied) moves upward by rotating pinion (2).

4. At this time, the distance that rack B (3) moves is longer than the distance that pinion (2) moves while rotating.

2 T202-03-05-006

5. The distance that rack B (3) moves can be calculated using the equation of H+H=2H. This principle is applied to the differential.

12-

T3-7-4

Rack A Pinion

Rack B

SECTION 3 COMPONENT OPERATION Group 7 Axle Operation of Differential y Traveling Straight 1. In case resistances applied to axle shafts (1, 7) connected to side gear (2) by spline joint are the same or when the machine is traveling straight on a smooth flat surface, idle gear (4) does not rotate.

9 4

2. Idle gear (4) and side gear (2) are proportionally "geared together", and rotate in unison with half case (6) and half gear (3)which are connected to ring gear (8). 2

3. When the rate of movement of each wheel is identical on each side, the differential function of the differential does not need to work, but side gear (2), idle gear (4), and spider (5) play only the role of joints for connecting axle shafts (1, 7).

3 T202-03-05-007

y When Steering 4. When the machine turns, uneven distances are applied to the drive wheels. Therefore, idle gear (4) begins revolving on side gear (2) while rotating around spider (5) due to the difference of the distances applied to the left and right tires.

9 4

5. Consequently, in case the resistance force applied to axle shaft (1) is great, idle gear (4) rotates in the same direction as the rotational direction on side gear (2). And the speed of axle shaft (1) is lowered and the amount of the speed reduction is applied to axle shaft (7), working the differential function.

6. Suppose ring gear (8) is driven by pinion shaft (9) at the speed of 100. In the condition that the machine is traveling straight, the drive wheels on the both sides rotate at the same speed. 7. When the machine turns and the speed of the right drive wheel is lowered to 90, the left wheel turns at the speed of 100+(100-90)=110 as the speed of 10 (100-90=10) is added to the speed of the left wheel.

8. If ring gear (8) rotates at the speed of 100, the summation of the speeds of the left and right wheels becomes always 200 regardless of movement of the respective wheels.

T3-7-5

2 5

T202-03-05-008

SECTION 3 COMPONENT OPERATION Group 7 Axle Torque Proportioning Differential (TPD) A wheel loader is operated mostly on rough surfaces. With scuffing of tires, working efficiency and tire life is lessened. In order to avoid loss of working efficiency and tire life, the axle is provided with the torque proportioning differential. Differential pinion gear (2) of the torque proportioning differential has an odd number of teeth, and differential pinion gear (2) and side gears (1, 3) have special teeth in shape. If the surface resistance values of the right and left wheels differ from each other, engagement position of pinion gear (2) with left and right side gears (1, 3) will be automatically shifted to transmit different torque, to the left and right wheels. Different torque in right and left wheels prevents the tires from slipping.

Forward Rotation

12-

Left Side Gear Differential Pinion Gear

Right Side Gear

T3-7-6

T487-03-06-015

SECTION 3 COMPONENT OPERATION Group 7 Axle Traveling Straight with the Same Road Resistances to Left and Right Tires

1. In case resistances to the left and right tires are the same, distance a and distance b from differential pinion gear (2) center to the respective contact points of left and right side gears (1, 3) are the same.

2. Therefore, differential pinion gear (2) and left and right side gears (1, 3) solidly rotate toward forward, and the drive forces of the left and right tires are the same.

T487-03-06-016

Traveling on Soft Roads (Different Road Resistances to Left and Right Tires) 1. While traveling on soft roads, if the left tire slips, left side gear (1) on the left tire receiving little resistance tends to rotate more forward than right side gear (3). 2. This rotation causes deviation of the contact points of differential pinion gear (2) and left and right side gears (1, 3) in the torque proportioning differential.

T487-03-06-017

3. When left side gear (1) rotates slightly more forward than right side gear (3), distance a of the contact point of differential pinion gear (2) and left side gear (1) is longer than distance b of right side gear (3). Correlation of the forces at this time is as follows. a × TA (force applied to left side gear (1)) = b × TB (force applied to right side gear (3)) 4. Until the difference of the road resistances exceeds the certain value, differential pinion gear (2) does not rotate, but left and right side gears (1, 3) rotate at the same speed solidly. 5. Besides, the left tire does not rotate redundantly and does not slip. (The right tire can have drive force larger than the left tire.) 6. Therefore, tire life is prolonged, and working efficiency is improved.

T3-7-7

SECTION 3 COMPONENT OPERATION Group 7 Axle Limited Slip Differential (LSD) (Option) LSD is so constructed so that clutch disc (5) is inserted between pressure ring (2) supporting spider (8) with the cam and case (6), which increases restriction of different movement and assists to keep the left and right side tire speeds close to the same. In addition, the left to right tractive ratio is better for traction than the TPD style differentials.

A wheel loader, as required by the kind of work, must be operated in places where skidding takes place easily like sand and muddy soil. In places like these, tires can slip even if the torque proportioning differential (TPD) is installed. Rotation is transmitted to the slipping tire, but not to the tires contacting the earth, so not only is the function of the wheel loader worsened, but the tire lives are shortened. To avoid this, a limited slip differential (LSD) (equipped with a differential and axle shaft movement restriction device) can be provided to help avoid loose movement of one side of the axle, and provide more stable tractive conditions. Drive force between the left and right side is more stable.

1 2 3

4 5 6 8

T4GB-03-10-003

12-

Ring Gear Pressure Ring

34-

Side Gear Pressure Plate

56-

T3-7-8

Clutch Disc Case

78-

Pinion Gear Spider

SECTION 3 COMPONENT OPERATION Group 7 Axle Traveling Straight with the Same Road Resistances to Left and Right Tires As the differential pinion gear and the left and right pinion gears rotate together simultaneously, the drive forces of the left and right tires are the same, similar to the TPD.

Traveling on Soft Roads (Different Road Resistances to Left and Right Tires) 5

1. Drive force is transmitted to the case, pressure ring (2), and spider (8) through the ring gear.

2. At this time, spider (8) having the cam construction pushes pressure ring (2) toward the case with thrust P. 8

3. Clutch disc (5) is geared with the case through pressure ring (2).

2 T4GB-03-10-004

4. Side gears connected to clutch disc (5) by spline joint rotate solidly with the case, and the left and right side gears rotate at the same speed.

24-

5. Therefore, the left and right axle shafts connected to the side gears by spline joint tend to rotate solidly, together with the case, and the differential movement restriction works, resulting in better overall traction and less tire slippage. 6. When the drive force provided for the skidding tire is greater than the road resistance, part of the torque of the skidding tire is added to the tire contacting the road by the differential movement restriction (because of the same rotation speed of the left and right tires), and the tire contacting the road is provided with more torque. 7. Until the difference of the resistances between the left and right tires exceeds the clutch friction gripping value (until the clutch disc begins to slip), the left and right gears solidly turn together at a constant speed. 8. On such soft roads, the drive force increases by 1.5 times the value for the TPD if the LSD is provided.

T3-7-9

Pressure Ring Pressure Plate

58-

Clutch Disc Spider

SECTION 3 COMPONENT OPERATION Group 7 Axle Service Brake The type of service brake used is a wet-type multi-disc brake and is assembled in the differential housing of the axle. All four wheels are equipped with wet disc brakes.

yWhen brake is applied 1. Pressure from the brake valve works on the back of brake piston (5) and moves brake piston (5), so that brake friction disc (3) and brake plate (2) are compressed. 2. The inner surface of brake disc (3) is splined to shaft (8) through disk hub (7). 3. In addition, the outer surface of brake plate (2) is fixed to differential housing (4). 4. Therefore, the rotation of applied and compressed brake disc (3) stops, slowing the machine.

y When brake is released 1. Pressure from the brake valve is reduced, brake piston (5) is returned by return spring (6). 2. Brake friction disc (3) is released and machine brakes are released.

T3-7-10

SECTION 3 COMPONENT OPERATION Group 7 Axle 2

a 9

T4FJ-03-07-003

When brake is applied

When brake is released 4

c 8

9 9

T4FJ-03-07-005

T4FJ-03-07-004

Brake Pressurized Oil

From Brake Valve

To Brake Valve

123-

Axle Shaft Final Drive End Plate

45-

Pin Brake Disc

67-

Brake Ring Brake Piston

T3-7-11

89-

Differential Body Shaft

SECTION 3 COMPONENT OPERATION Group 7 Axle Final Drive / Axle Shaft Final drive (2) is the device for finally decreasing the speed in the power transmission system, and of the planetary gear type. As for power transmission, the power from the differential is transmitted from shaft (7) and rotates three planetary gears (4) in ring gear (3). The rotation of planetary gear (4) is transmitted to axle shaft (1) through planetary carrier (5). View A

2 3

T4FJ-03-07-006 Section A

7 4 T4FJ-03-07-007

12-

Axle Shaft Final Drive

34-

Ring Gear Planetary Gear

56-

T3-7-12

Planetary Carrier Housing

Shaft

SECTION 3 COMPONENT OPERATION Group 8 Brake Valve Outline Brake valve (1) consists of booster (2) and master cylinder (3). Pressurized oil (a) from the brake/transmission pump is routed to booster (2). Booster (2) pushes master cylinder (3) to the right according to the stroke of brake pedal (c). As master cylinder (3) is moved together with booster (2), the service brakes of front and rear axles are applied.

3 T487-03-07-001

Pressurized Oil from Brake/ Transmission Pump

bc-

To Transmission (Oil Pan) From Brake Pedal

Brake Valve

Booster

T3-8-1

Master Cylinder

SECTION 3 COMPONENT OPERATION Group 8 Brake Valve Structure The brake valve consists of dust cover (1), cover (2), relief valve (3), pistons (7, 12, 18), and spool (20). Brake pedal (c) is directly connected to spool (20) of the brake valve. When brake pedal (c) is stepped on, spool (20) is moved. The brake valve is connected to the brake/transmission pump, transmission, and the brake oil reserve tank.

T3-8-2

SECTION 3 COMPONENT OPERATION Group 8 Brake Valve

a 1

d 4

18 17

15 14

12 11 10

5 T487-03-07-001

Pressurized Oil from Brake/ Transmission Pump

bc-

To Transmission (Oil Pan) From Brake Pedal

To Brake Oil Reserve Tank

12345-

Dust Cover Cover Relief Valve Relief Port Rear Brake Chamber

678910-

Spring Piston Spring Front Brake Chamber Rear Cushion Rod

1112131415-

Rear Cushion Piston Piston Connector Rod Spring

NOTE: The illustration shows the state of the brake valve when brake pedal (c) is not stepped on.

T3-8-3

1617181920-

Spring Chamber B Piston Chamber A Spool

SECTION 3 COMPONENT OPERATION Group 8 Brake Valve Operation When in neutral (the brake pedal is released): 1. When brake pedal (22) is released, spool (20) is pushed to the left by spring (16). 2. Under this condition, passage (21) between spool (20) and piston (18) is opened so that pressurized oil (a) from the brake/transmission pump flows to transmission (oil pan) (b) through passage (21) and chamber B (17). 3. Pistons (7, 12) are also pushed to the left by springs (6, 8). Front brake chamber (9) is connected to service bake (25) of the front axle. In addition, rear brake chamber (5) is connected to service brake (24) of the rear axle. 4. When pistons (7, 12) are pushed to the left, front brake chamber (9) and rear brake chamber (5) are connected to brake oil reserve tank (23) through relief ports (4). 5. Therefore, the pressure in front brake chamber (9) and rear brake chamber (5) are equal to the pressure in brake oil reserve tank (23). 6. As the pressure routed to service brakes (24, 25) are equal to the pressure in brake oil reserve tank (23), service brakes (24, 25) are not applied.

T3-8-4

SECTION 3 COMPONENT OPERATION Group 8 Brake Valve

23 a

9 20

21 18 17

24 T4FJ-03-08-001

Pressurized Oil from Brake/ Transmission Pump

To Transmission (Oil Pan)

456789-

Relief Port Rear Brake Chamber Spring Piston Spring Front Brake Chamber

101112131415-

Rear Cushion Rod Rear Cushion Piston Piston Connector Rod Spring

161718192021-

T3-8-5

Spring Chamber B Piston Chamber A Spool Passage

22232425-

Brake Pedal Brake Oil Reserve Tank Service Brake (Rear Axle) Service Brake (Front Axle)

SECTION 3 COMPONENT OPERATION Group 8 Brake Valve When the brake is applied (when the brake pedal is stepped on): 1. When brake pedal (22) is stepped on, spool (20) is moved to the right and passage (21) between spool (20) and piston (18) becomes narrow. 2. When passage (21) between spool (20) and piston (18) becomes narrow, pressure difference between chamber A (19) and chamber B (17) occurs. 3. As the pressure in chamber A (19) is higher than that in chamber B (17), piston (18) is moved to the right and pushes connector (13) to the right. 4. Then, connector (13) pushes piston (12) to the right and piston (12) closes relief port (4). As relief port (4) is closed and piston (12) is moved to the right, the pressure in front brake chamber (9) increases. 5. In addition, piston (7) is also moved to the right and the pressure in rear brake chamber (5) also increases. 6. As the pressure in front brake chamber (9) and rear brake chamber (5) increase, service brakes (24, 25) are applied. 7. And, the circuit to front brake chamber (9) is separated from that to rear brake chamber (5). Even if an oil leakage occurs in either of the circuits, the other brake system can be operated normally. 8. While service brakes (24, 25) are applied, pressurized oil in front brake chamber (9) is routed to reaction piston (11) and moves reaction piston (11) to the left. 9. When reaction piston (11) touches rod (14), rod (14) is also pushed to the left. Then, rod (14) pushes brake pedal (22) via spool (20). 10. Therefore, pressure in front brake chamber (9) is transmitted to brake pedal (22) as a reaction force.

T3-8-6

SECTION 3 COMPONENT OPERATION Group 8 Brake Valve

23 a

4 22

9 20

18 17

11 12

24 T4FJ-03-08-02KC

a456789-

Pressurized Oil from Brake/ Transmission Pump Relief Port Rear Brake Chamber Spring Piston Spring Front Brake Chamber

101112131415-

Rear Cushion Rod Rear Cushion Piston Piston Connector Rod Spring

161718192021-

T3-8-7

Spring Chamber B Piston Chamber A Spool Passage

22232425-

Brake Pedal Brake Oil Reserve Tank Service Brake (Rear Axle) Service Brake (Front Axle)

SECTION 3 COMPONENT OPERATION Group 8 Brake Valve (Blank)

T3-8-8

SECTION 3 COMPONENT OPERATION Group 9 Others Propeller Shaft Propeller shafts are installed between the transmission and the front axle, and between the transmission and the rear axle, respectively. Propeller shafts transmit the power from the transmission to the front axle and the rear axle. The adopted joint is universal joint (1) most commonly used.

Between Front Axle and Transmission 1

T4GB-03-12-003

Between Transmission and Rear Axle 1

TNCC-03-09-001

Universal Joint

T3-9-1

SECTION 3 COMPONENT OPERATION Group 9 Others Inching Valve (Declutch Valve) The inching (declutch) valve is operated by brake pedal (a), which rotates the spool, flows HST charge pressure oil to the hydraulic oil tank, decreases the HST pump displacement angle control pressure, and decreases the HST pump delivery flow rate.

1. When brake pedal (a) is stepped on, spool (2) rotates via lever (1) which is in conjunction with brake pedal (a). Pressurized oil from the DA valve flows to port P and flows to the hydraulic oil tank through notch (3) on spool (2) and port T.

3. Therefore, the HST pump displacement control pressure decreases. As the displacement angle control cylinder moves toward the neutral position, the HST pump rotation speed decreases.

4. Consequently, as pressurized oil flow rate flowing from the HST pump to the HST motor decreases, the HST motor rotation speed decreases.

2. As the notch (3) size of spool (2) increases according to the brake pedal (a) depressing amount, pressurized oil flow rate flowing to the hydraulic oil tank also increases.

Section A-A

1 A T

T4FJ-03-09-001

Brake Pedal

P-

Port P

T-

Port T

Lever

Spool

Notch

T3-9-2

SECTION 3 COMPONENT OPERATION Group 9 Others Pilot Shut-Off Solenoid Valve (Only Hydraulic Pilot Type) (Option) Section Z-Z

The pilot shut-off solenoid valve is a solenoid valveoperated switch valve. Spool (1) in the pilot shut-off solenoid valve is shifted by the control lever lock switch and turns ON/OFF pilot pressure oil to the pilot valve and quick coupler (option).

T1 to T4

P A1 to A4

1 T1V1-03-07-012 Z

A3 Z T4

T1V1-03-07-011

P- From HST Charge Pump A1- (Unused) A2- Lift Arm, Bucket, Auxiliary Pilot Pressure 1-

A3- (Unused) A4- Quick Coupler (Option) Pilot Pressure

T1- Returning Oil to Hydraulic Oil Tank T2- (Unused)

Spool

T3-9-3

T3- Returning Oil from Lift Arm, Bucket, Auxiliary Pilot T4- Returning Oil from Quick Coupler (Option) Pilot

SECTION 3 COMPONENT OPERATION Group 9 Others y Pilot Shut-Off Lever: LOCK Position

Pilot Shut-Off Lever: LOCK Position

1. When the pilot shut-off lever is set to the LOCK position, the pilot shut-off relay is turned OFF and the pilot shut-off solenoid valve is turned OFF. (Refer to SYSTEM / Electrical System.)

T1 toT4

2. Pressurized oil from the HST charge pump is blocked by spool (1) in the pilot shut-off solenoid valve.

P A1 to A4

3. Pressurized oil in the pilot valve (A2) and quick coupler (option) (A4) sides flow to the hydraulic oil tank. 4. Therefore, even if the control lever is operated, the pilot valve is not activated.

1 T1J1-03-07-011

y Pilot Shut-Off Lever: UNLOCK Position

Pilot Shut-Off Lever: UNLOCK Position

1. When the pilot shut-off lever is set to the UNLOCK position, the pilot shut-off relay is turned ON and the pilot shut-off solenoid valve is excited. (Refer to SYSTEM / Electrical System.)

T1 to T4

2. Therefore, spool (1) in the pilot shut-off solenoid valve is pushed down and returning oil from the pilot valve and quick coupler (option) are blocked by spool (1).

P A1 to A4

3. Pressurized oil from the HST charging pump flows to the pilot valve and quick coupler. 4. Consequently, when the control lever is operated, the pilot valve is activated.

1 T1J1-03-07-001

P- From HST Charge Pump A1- (Unused) A2- Lift Arm, Bucket, Auxiliary Pilot Pressure A3- (Unused) A4- Quick Coupler (Option) Pilot Pressure 1-

T3-9-4

Spool

T1- Returning Oil to Hydraulic Oil Tank T2- (Unused) T3- Returning Oil from Lift Arm, Bucket, Auxiliary Pilot T4- Returning Oil from Quick Coupler (Option) Pilot

SECTION 3 COMPONENT OPERATION Group 9 Others HST Cooler Bypass Check Valve HST cooler bypass check valve (1) is provided in the circuit between drain circuits in HST pump and HST motor and hydraulic oil tank. When abnormal pressure is generated in the circuit, HST cooler bypass check valve (1) is operated and releases abnormal pressure.

a, b

TNDF-03-14-001

From HST Pump (Port T2)

HST Cooler Bypass Check Valve

From HST Motor (Port T2)

T3-9-5

To Hydraulic Oil Tank

SECTION 3 COMPONENT OPERATION Group 9 Others Pilot Accumulator (Only Hydraulic Pilot Type) (Option) The pilot accumulator is installed in the pilot circuit (option). High-pressure nitrogen gas is contained in the accumulator, and pressurized oil from the HST charging pump compresses the nitrogen gas through diaphragm (1). The pilot circuit pressure oil is retained by compression of the nitrogen gas.

IMPORTANT: The accumulator cannot be disassembled due to structural problem. Replace it as an assembly if necessary.

T4GB-03-06-011

Diaphragm

T3-9-6

SECTION 3 COMPONENT OPERATION Group 9 Others Ride Control Accumulator (Option) The ride control accumulator is installed in the accumulation circuit of the ride control. High-pressure nitrogen gas is contained in the accumulator, and pressurized oil compresses the nitrogen gas through the piston. Compression of the nitrogen gas dampens the shock of pressurized oil due to pitching of the lift arm cylinder raise circuit.

TNDB-03-08-009

T3-9-7

SECTION 3 COMPONENT OPERATION Group 9 Others Secondary Steering Check Block (Option) 4

Secondary steering check block (1) is installed between the priority valve and the steering valve. Built-in check valve (2) is provided for preventing delivery pressure oil (B) of the secondary steering pump from flowing to the priority valve. In addition, check valve (4) is provided for preventing pressurized oil of the priority valve from flowing to the secondary steering pump.

1 D B

2 A

TNCC-03-09-002

Section Z-Z A

Z TNCC-03-09-003 D

AB-

Port A (From Priority Valve) Port B (From Secondary Steering Pump)

C-

Dr- To Hydraulic Oil Tank

D-

Port C (Steering Pressure Switch Mounting Port) Port D (To Steering Valve)

Secondary Steering Check Block

23-

Check Valve Steering Pressure Switch

T3-9-8

Check Valve

SECTION 3 COMPONENT OPERATION Group 9 Others Secondary Steering Pump (Option) The secondary steering pump is started in case supply of the pressurized oil from the main pump is suddenly stopped. The secondary steering pump is installed for supplying pressurized oil to the steering valve in place of the main pump until the time when the machine is moved to a safe place.

The secondary steering pump consists of gear pump (2), electric motor (3), and relief valve (1).

TNED-01-02-019

Relief Valve

Gear Pump

T3-9-9

Electric Motor

SECTION 3 COMPONENT OPERATION Group 9 Others Oil Filter The filter is provided in each circuit of HST charge oil filter (1) and brake/transmission oil filter (2). The relief valve is built in each filter. When abnormal pressure (abnormally high pressure) is generated in delivery pressure oil from each pump, the filter is protected.

M4FJ-07-009

1 12-

T3-9-10

HST Charge Oil Filter Brake/Transmission Oil Filter

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Outline Ride control valve (option) (1) makes the machine travel stable by reducing the force generated in lift arm cylinder when driving on rough. Ride control valve (1) consists of ride control solenoid valve (3), ride control spool, charge-cut spool, and overload relief valve (9). (Refer to SYSTEM / Hydraulic System.)

TNDB-03-12-001

Ride Control Valve

Ride Control Solenoid Valve

T3-10-1

Overload Relief Valve

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Ride Control Hydraulic Circuit

PS2

A1 B1

Pi a

11 9

A B

5 TNDB-03-12-002

A1- Lift Arm Cylinder Bottom Side Circuit B1- Lift Arm Cylinder Rod Side Circuit

aA-

1234-

5678-

Ride Control Valve Ride Control Accumulator Ride Control Solenoid Valve Lift Arm Cylinder

ON Signal from MC Port A (from Lift Arm Cylinder Bottom Side)

B-

HST Charge Pump Hydraulic Oil Tank Charge-Cut Spool Ride Control Spool

9- Overload Relief Valve 10- Orifice 11- Drain Plug

Pi-

T3-10-2

Port B (to Lift Arm Cylinder Rod Side) Port Pi (Pilot Pressure Oil)

PS2- Port PS2 (to Ride Control Accumulator) T- Port T (to Hydraulic Oil Tank)

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Layout PS2

9 b

a A

Section a-a

TNDB-03-12-001

Section b-b

PS2

PS2 A T T TNDB-03-12-003

T3-10-3

T4GD-03-08-001

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Operation 1. When the ride control is not activated, the oil passage between port Pi and output port (2) is blocked by spool (3) in ride control solenoid valve (4). 2. When the conditions for ride control exist, the ON signal from MC excites the solenoid in ride control solenoid valve (4) and spool (3) moves right. 3. Therefore, the oil passage between port Pi and output port (2) is opened. 4. Pilot pressure oil from port Pi flows to output port (2) through spool (3) in ride control solenoid valve (4). 5. When the pressure in output port (2) exceeds the spring (7) force, ride control spool (1) moves right (to the spring (7) side). 6. Therefore, the circuit between port A (the bottom side of lift arm cylinder) and port PS2 (the ride control accumulator) is connected. 7. At the same time, the circuit between port B (the rod side of lift arm cylinder) and port T (hydraulic oil tank) is connected. 8. Consequently, when the force pushing down the lift arm cylinder occurs, the circuit pressure increases and this pressure is reduced by accumulator (6). 9. In addition, the negative pressure in the circuit due to the force pushing down the lift arm is canceled by drawing hydraulic oil supplied from port T.

T3-10-4

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve

5 Pi

PS2

3 2 7

A-

123-

Port A (from Lift Arm Cylinder Bottom Side)

Ride Control Spool Output Port Spool

B-

Pi-

Port B (to Lift Arm Cylinder Rod Side) Port Pi (Pilot Pressure Oil)

PS2- Port PS2 (to Ride Control Accumulator) T- Port T (to Hydraulic Oil Tank)

456-

Ride Control Solenoid Valve HST Charge Pump Ride Control Accumulator

78-

T3-10-5

Spring Hydraulic Oil Tank

TNDB-03-12-006

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Charge-Cut Spool Charge-cut spool (3) makes the ride control accumulator accumulate pressurized oil up to the set pressure. In addition, it keeps the pressure in the ride control accumulator when the ride control accumulator pressure is accumulated to the set pressure. 1. When the ride control is not activated, pressurized oil from the lift arm cylinder bottom side flows to port X through port A and orifice (1). 2. Pressurized oil from port X flows through chargecut spool (3), pushes to open check valve (2), and flows to port Y. 3. Pressurized oil from port Y flows to ride control accumulator and is accumulated. 4. As sectional area M (5) of charge-cut spool (3) is larger than sectional area N (6) and when the ride control accumulator pressure is accumulated to the set pressure, pressurized oil in port X pushes charge-cut spool (3) to the spring (4) side. 5. As charge-cut spool (3) moves to the spring (4) side, the oil passage between port X and port Y is closed. 6. Therefore, pressurized oil is stopped accumulating in the ride control accumulator.

T3-10-6

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve When accumulating accumulator pressure A

PS2

T4GB-03-08-007

After accumulating accumulator pressure

To Ride Control Accumulator

A-

Port A (from Lift Arm Cylinder Bottom Side)

XY-

Port X Port Y

12-

Orifice Check Valve

34-

Charge-Cut Spool Spring

56-

Sectional Area M Sectional Area N

T3-10-7

T4GB-03-08-008

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Overload Relief Valve The overload relief valve prevents the hoses and the ride control accumulator from being damaged in case pressure in the bottom side circuit of the lift arm cylinder is suddenly raised by an external force or something during operation of the lift arm cylinder.

Relief Operation 1. Pressure in port HP (actuator circuit) is routed to pilot poppet (8) through orifice A (2) in main poppet (1) and orifice B (3) in seat (4). 2. When pressure in port HP reaches the set force of spring B (6), pilot poppet (8) is opened and pressurized oil flows to port LP (the hydraulic oil tank) through passage A (5) and the periphery of sleeve (11). 3. At this time, a pressure difference is caused between port HP and spring chamber (10) due to orifice A (2). 4. When this pressure difference reaches the set pressure of spring A (9), main poppet (1) is opened and pressurized oil from port HP flows to port LP. 5. Consequently, the actuator circuit pressure decreases. 6. When the actuator circuit pressure decreases to the specified pressure, main poppet (1) is closed by the force of spring A (9).

T3-10-8

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Normal Operation: 12

T176-03-03-012

Relief Operation: 1

HP- Actuator Circuit

LP- Hydraulic Oil Tank

123-

456-

Main Poppet Orifice A Orifice B

Seat Passage A Spring B

8- Pilot Poppet 9- Spring A 10- Spring Chamber

T3-10-9

T176-03-03-013

11- Sleeve 12- Spring C 13- Make-Up Valve

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Make-Up Operation 1. When pressure in port HP (actuator circuit) decreases lower than pressure in port LP (hydraulic oil tank), make-up valve (13) moves left. 2. Hydraulic oil in port LP flows to port HP and cavitation is prevented. 3. When pressure in the port HP side increases to the specified pressure, make-up valve (13) is closed by the force of spring C (12).

T3-10-10

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Make-Up Operation: 12

TNDB-03-12-013

HP- Actuator Circuit

LP- Hydraulic Oil Tank

12- Spring C

13- Make-Up Valve

T3-10-11

SECTION 3 COMPONENT OPERATION Group 10 Ride Control Valve Drain Plug The ride control valve is provided with drain plug (2) in order to return pressure oil of the ride control accumulator to hydraulic oil tank (4) at the time of maintenance or something. Pressurized oil from the ride control accumulator flows to hydraulic oil tank (4) by loosening drain plug (2). Therefore, the pressure of ride control accumulator decreases. Do not loosen drain plug (2) too much CAUTION: as pressurized oil may spout out due to removal of drain plug (2). Do not loosen drain plug (2) more than 2 turns.

1 2 3

From Ride Control Accumulator

12-

Lock Nut Drain Plug

34-

Overload Relief Valve Hydraulic Oil Tank

T3-10-12

TNDB-03-12-010

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Joystick Type Pilot Valve for Front Attachment (Hydraulic Pilot Type) (Option) Outline The pilot valve controls pilot pressure oil in order to move the spool in the control valve. The pilot valve outputs pressure according to the control lever stroke by PPC (Pressure Proportional Control Valve) function and moves the spool in the control valve. Port No. 1 2 3 4

Lift Arm Lower Bucket Dump Lift Arm Raise Bucket Rollback

Hydraulic Symbol

P T 2

1 T4GB-03-05-001

PT-

T3-11-1

Port P (Pressurized Oil from HST Charging Pump) Port T (To Hydraulic Oil Tank)

TNCC-03-11-001

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve (Blank)

T3-11-2

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Operation The spool (7) head comes in contact with the upper surface of spring guide (4). Spring guide (4) is kept raised by return spring (6). NOTE: Total lever stroke is determined by stroke dimension (E) of pusher (2).

2 4 7

6 8 3 TNED-03-06-003

12-

Cam Pusher

34-

Casing Spring Guide

56-

T3-11-3

Balance Spring Return Spring

78-

Spool Hole

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Neutral (Output Curve: A to B) 1. When in neutral, spool (7) completely blocks pressurized oil from port P (HST charging pump). In addition, the output port is opened to port T (hydraulic oil tank) through the inner passage in spool (7).

2. Therefore, pressure in the output port is equal to that in port T. 3. When the control lever is slightly tilted, cam (1) is tilted and pusher (2) is pushed downward. Pusher (2) compresses return spring (6) along with spring guide (4) together.

4. At this time, as pressure in the output port is equal to that in port T, spool (7) moves downward due to the balance spring (5) force while keeping the lower surface of the spool (7) head in contact with spring guide (4).

T523-02-05-001 a-

5. This status continues until hole (8) on spool (7) is connected to port P.

T3-11-4

Pilot Pressure

Control Lever Stroke

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve

4 7

3 P

TNED-03-06-003

P-

Port P

T-

Port T

Output Port

12-

Cam Pusher

34-

Casing Spring Guide

56-

Balance Spring Return Spring

T3-11-5

TNED-03-06-004

78-

Spool Hole

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve During Metering or Decompressing (Output Curve: C to D) 1. When the control lever is further tilted and pusher (2) is moved downward further, hole (8) on spool (7) is connected to port P and pressurized oil in port P flows to the output port.

2. Pressure in the output port is routed to the bottom surface of spool (7) so that spool (7) is pushed upward. C

3. When the force to move spool (7) upward is smaller than the balance spring (5) force, balance spring (5) is not compressed so that spool (7) is not raised and pressure in the output port increases. 4. As pressure in the output port increases further, the force to move spool (7) upward increases. When this force overcomes the balance spring (5) force, spool (7) compresses balance spring (5) and moves upward.

T523-02-05-001 a-

5. As spool (7) is moved upward, hole (8) is closed so that pressurized oil from port P stops flowing to the output port and pressure in the output port stops increasing. 6. As spool (7) is moved downward and balance spring (5) is compressed, pressure routed to the bottom surface of spool (7) increases until pressure balances with the increasing spring force. This increasing pressure becomes pressure in the output port.

T3-11-6

Pilot Pressure

Control Lever Stroke

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve

4 7

3 P

TNED-03-06-005

P-

Port P

T-

Port T

Output Port

12-

Cam Pusher

34-

Casing Spring Guide

56-

Balance Spring Return Spring

T3-11-7

TNED-03-06-006

78-

Spool Hole

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Full Stroke (Output Curve: E to F) 1. When the control lever is fully stroked, the balance spring (5) force (force to push spool (7) downward) becomes larger than pressure in output port (a) (force to push spool (7) upward).

2. Therefore, even if pressure in output port (a) increases further, hole (8) on spool (7) is kept open. 3. Consequently, pressure in output port (a) is equal to that in port P.

T523-02-05-001 a-

T3-11-8

Pilot Pressure

Control Lever Stroke

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve

2 4 7

6 8 3 P

TNED-03-06-007

P-

Port P

T-

Port T

Output Port

12-

Cam Pusher

34-

Casing Spring Guide

56-

Balance Spring Return Spring

T3-11-9

78-

Spool Hole

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Electromagnetic Detent 1. The coil for detent is installed in the pilot valve. 2. If the control lever is fully stroked, plate (9) is adsorbed by coil assembly (10). 3. Adsorption condition is retained until coil assembly (10) is unexcited or until adsorption is forcefully cancelled by operating the control lever toward the other direction.

TNED-03-06-007

Plate

10- Coil Assembly

T3-11-10

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Auxiliary Pilot Valve (Hydraulic Pilot Type) (Option) Outline The two-direction, four-port type (Optional) is adopted for the additional circuit pilot valve. Port No. 1 2

Optional Optional

T T

Hydraulic Symbol

P P P

1 1

T554-02-07-009

P-

T3-11-11

T1LA-03-04-001

Port P (Pressurized Oil from HST Charging Pump)

T-

Port T (To Hydraulic Oil Tank)

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Operation Neutral (Output Curve: A to B) 1. At the neutral position of the control lever, spool (7) completely blocks the pressurized oil of port P. Also, outlet port (a) is connected to port T through passage (9) of spool (7), and the pressurized oil at output port (a) is equal to the pressure in the hydraulic tank.

p D

2. When the control lever is moved slightly, cam (1) is tilted. Then, pusher (2) and spring guide (4) remain mutually connected, compress return spring (6), and move downward. 3. At this time, spool (7) is pushed by balance spring (5) and moves downward until clearance (A) becomes 0 mm.

b T1F3-03-09-004

4. During this movement, output port (a) remains connected with port T and pressurized oil is not supplied to output port (a).

NOTE: Pedal stroke until clearance (A) becomes 0 mm is the play of the control lever.

T3-11-12

Pilot Pressure

Control Lever Stroke

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Neutral (Output Curve: A to B)

3 4 5 T

6 A

A: 0 P

8 7 9 a

T1LA-03-04-003

T1LA-03-04-002

PA-

Port P Clearance

TB-

Port T Notch Part

Output Port

123-

Cam Pusher Plate

456-

Spring Guide Balance Spring Return Spring

789-

Spool Hole Part Passage

T3-11-13

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve During Metering or Decompressing (Output Curve: C to D) 1. When the control lever is further tilted, hole part (8) of spool (7) is connected to notch part (B). p

2. Pressurized oil of port P flows to output port (a) through hole part (8) of spool (7) and pressure at output port (a) increases.

3. Pressure in output port (a) is routed to the bottom surface of spool (7) so that spool (7) is pushed upward.

4. When the force to move spool (7) upward is smaller than the balance spring (5) force, balance spring (5) is not compressed so that spool (7) is not raised and pressure in the output port (a) increases. 5. As pressure in the output port (a) increases further, the force to move spool (7) upward increases. When this force overcomes the balance spring (5) force, spool (7) compresses balance spring (5) and moves upward.

b T1F3-03-09-004

6. As spool (7) is moved upward, notch part (B) is closed so that pressurized oil from port P stops flowing to output port (a) and pressure at output port (a) stops increasing. 7. In this way, balance spring (5) is compressed by the amount that spool (7) is pushed down, and the pressure at output port (a) is the balanced pressure working on the spring force and spool (7).

T3-11-14

Pilot Pressure

Control Lever Stroke

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve During Metering or Decompressing (Output Curve: C to D)

5 T

B P

8 7 a

T1LA-03-04-004

PA-

Port P Clearance

TB-

Port T Notch Part

Output Port

123-

Cam Pusher Plate

456-

Spring Guide Balance Spring Return Spring

789-

Spool Hole Part Passage

T3-11-15

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve (Blank)

T3-11-16

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Auxiliary Joystick Type Pilot Valve (Hydraulic Pilot Type) (Option) Outline The joystick type (four-direction, four-port type) (Optional) is adopted for the additional circuit pilot valve. Port No. 1 2 3 4

Optional Optional Optional Optional

Hydraulic Symbol P

3 1

4 T105-02-07-020

T1V1-03-04-001 T P-

T3-11-17

Port P (Pressurized Oil from Pilot Pump)

T-

Port T (To Hydraulic Oil Tank)

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Operation The spool (6) head comes in contact with the upper surface of spring guide (3). Spring guide (3) is kept raised by return spring (5). Neutral (Output Curve: A to B) 1. When in neutral, spool (6) completely blocks pressurized oil from port P (pilot pump). In addition, output port (a) is opened to port T (hydraulic oil tank) through the inner passage in spool (6).

2. Therefore, pressure in output port (a) (to the control valve) is equal to that in port T.

3. When the control lever is slightly tilted, cam (1) is tilted and pusher (2) is pushed downward. Pusher (2) compresses return spring (5) along with spring guide (3) together. 4. At this time, as pressure in output port (a) is equal to that in port T, spool (6) moves downward due to the balance spring (4) force while keeping the lower surface of the spool (6) head in contact with spring guide (3).

T523-02-05-001 p-

5. This status continues until hole (7) on spool (6) is connected to port P.

T3-11-18

Pilot Pressure

Control Lever Stroke

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve

2 6

6 P

T1V1-03-04-007

P-

Port P

T-

Port T

Output Port

12-

Cam Pusher

34-

Spring Guide Balance Spring

56-

Return Spring Spool

T3-11-19

T1V1-03-04-008

Hole

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve During Metering or Decompressing (Output Curve: C to D) 1. When the control lever is further tilted and pusher (2) is moved downward further, hole (7) on spool (6) is connected to port P and pressurized oil in port P flows to output port (a).

2. Pressure in output port (a) is routed to the bottom surface of spool (6) so that spool (6) is pushed upward.

3. When the force to move spool (6) upward is smaller than the balance spring (4) force, balance spring (4) is not compressed so that spool (6) is not raised and pressure in output port (a) increases. 4. As pressure in the output port (a) increases further, the force to move spool (6) upward increases. When this force overcomes the balance spring (4) force, spool (6) compresses balance spring (4) and moves upward.

T523-02-05-001 p-

5. As spool (6) is moved upward, hole (7) is closed so that pressurized oil from port P stops flowing to output port (a) and pressure in output port (a) stops increasing. 6. In this way, balance spring (4) is compressed by the amount that spool (6) is pushed down, and the pressure at output port (a) is the balanced pressure working on the spring force and spool (6).

T3-11-20

Pilot Pressure

Control Lever Stroke

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve

6 T

T1V1-03-04-009

P-

Port P

T-

Port T

Output Port

12-

Cam Pusher

34-

Spring Guide Balance Spring

56-

Return Spring Spool

T3-11-21

T1V1-03-04-010

Hole

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve Full Stroke (Output Curve: E to F) 1. When the control lever is fully stroked, pusher (2) moves downward until it comes in contact with the shoulder part of the casing.

2. At this time, spool (6) is directly pushed by the bottom of pusher (2). Therefore, even if pressure in output port (a) increases further, hole (7) on spool (6) is kept open.

3. Consequently, pressure in output port (a) is equal to that in port P.

NOTE: Total lever stroke is determined by stroke

dimension (E) of pusher (2).

T523-02-05-001 p-

T3-11-22

Pilot Pressure

Control Lever Stroke

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve

1 2

3 4 5 E

6 T

T1V1-03-04-011

T1V1-03-04-007

P-

Port P

T-

Port T

Output Port

E-

Pusher Stroke

12-

Cam Pusher

34-

Spring Guide Balance Spring

56-

Return Spring Spool

Hole

T3-11-23

SECTION 3 COMPONENT OPERATION Group 11 Pilot Valve (Blank)

T3-11-24

INDEX

A Accelerator Pedal Control...................................................... T2-2-4 Accessory Circuit ....................................................................T2-5-29 Accessory Circuit (Key Switch: ACC) .................................. T2-5-8 Accumulator ............................................................................... T3-6-8 Alternator Operation.............................................................T2-5-18 Auxiliary Joystick Type Pilot Valve) (Option) .............. T3-11-17 Auxiliary Pilot Valve (Option)........................................... T3-11-11 Axle Shaft ..................................................................................T3-7-12 Axle, Outline ............................................................................... T3-7-1 B Backup Light Lighting Control ..........................................T2-2-46 Brake Circuit .............................................................................T2-4-37 Brake Light Circuit ..................................................................T2-5-62 Brake Valve, Operation ........................................................... T3-8-4 Brake Valve, Outline ................................................................. T3-8-1 Brake Valve, Structure ............................................................. T3-8-2 Bucket Auto Leveler Control...............................................T2-2-56 Bucket Circuit ...........................................................................T2-4-14 C Cab Light Circuit .....................................................................T2-5-44 CAN Circuit.................................................................................. T2-1-2 CAN Circuit.................................................................................. T2-5-6 Charge Circuit, HST ................................................................T2-4-24 Charge-Cut Spool ...................................................................T3-10-6 Charging Circuit (Key Switch: ON) ....................................T2-5-16 Clutch Circuit ...........................................................................T2-4-33 Combined Operation Circuit ..............................................T2-4-18 Control System, Outline ......................................................... T2-2-1 Control Valve ............................................................. T1-2-13, T3-2-1 Controller, Outline.................................................................... T2-1-1 Cutoff Valve...............................................................................T3-1-15 D DA Valve .....................................................................................T3-1-10 Declutch Valve ........................................................................... T3-9-2 Differential .................................................................................. T3-7-2 Differential, Operation ............................................................ T3-7-5 Differential, Principle ............................................................... T3-7-4 Differential, Purpose ................................................................ T3-7-3 Displacement Angle Control Cylinder .............................. T3-1-4 Displacement Angle Control Solenoid Valve ................. T3-5-5 Drain Plug............................................................................... T3-10-12 Driving Slow Speed Selection Control............................T2-2-22 Driving Slow Speed Selection Control............................T2-2-40 Driving Slow Speed Switching Shock Reduction Control T22-34 E ECM System, Outline ............................................................... T2-3-1 EGR Control ..............................................................................T2-3-10

Electric Power Circuit (Key Switch: OFF)........................... T2-5-4 Electrical Component, Specifications .............................T1-3-12 Electrical System (Cab) ........................................................... T1-2-5 Electrical System (Components Related with Engine) T1-2-4 Electrical System (Components Related with Relays) . T1-2-4 Electrical System (Overview) ................................................ T1-2-3 Electrical System, Outline ...................................................... T2-5-1 Engine.........................................................................................T1-2-10 Engine Accessories, Specifications..................................... T1-3-5 Engine Control........................................................................... T2-2-3 Engine Control System Layout ............................................ T2-2-3 Engine Oil Pressure Alarm Control ...................................T2-3-16 Engine Performance Curve (TCD3.6 L4) ........................... T1-3-4 Engine Protection Control...................................................T2-2-30 Engine Starting Circuit (Key Switch: START) .................T2-5-14 Engine Stop Circuit ................................................................T2-5-22 Engine Trouble Alarm Control ...........................................T2-3-14 Engine, Electrical System ....................................................... T1-2-4 Engine, Specifications ............................................................. T1-3-1 F Fast speed mode ...................................................................... T3-6-2 Final Drive .................................................................................T3-7-12 Flushing Valve ..........................................................................T3-5-10 Forward Circuit, HST ..............................................................T2-4-26 Forward/Reverse Control Solenoid Valve ......................T3-1-11 Forward/Reverse Lever Control........................................... T2-2-8 Front Cab Light Circuit..........................................................T2-5-44 Front Console............................................................................. T1-2-6 Front Washer Circuit ..............................................................T2-5-36 Front Wiper Circuit (Fast) .....................................................T2-5-34 Front Wiper Circuit (INT) ......................................................T2-5-30 Front Wiper Circuit (Slow)....................................................T2-5-32 Fuel Injection Amount Control ............................................ T2-3-4 Fuel Injection Control ............................................................. T2-3-2 Fuel Injection Pressure Control ........................................... T2-3-6 Fuel Injection Rate Control ................................................... T2-3-8 Fuel Injection Timing Control .............................................. T2-3-8 H H Position, Light SW ..............................................................T2-5-50 Hazard Light Circuit ...............................................................T2-5-64 High-Beam Circuit ..................................................................T2-5-52 High-Pressure Relief Valve ...................................................T3-1-18 Horn Circuit ..............................................................................T2-5-66 HST Brake ..................................................................................T2-2-14 HST Charging Pump ..............................................................T3-1-23 HST Circuit.................................................................................T2-4-22 HST Cooler Bypass Check Valve........................................... T3-9-5 HST Motor .................................................................................T1-2-12 HST Motor Control .................................................................T2-2-20 HST Motor, Outline .................................................................. T3-5-1 HST Pump.................................................................................... T3-1-2 HST Pump Control.................................................................... T2-2-6

60Z7 F&S

INDEX

HST Pump Control System Layout ..................................... T2-2-7 Hydraulic Circuit .....................................................................T3-2-16 Hydraulic Circuit ....................................................................... T3-2-4 Hydraulic Component, Specifications .............................. T1-3-7 Hydraulic System, Outline ..................................................... T2-4-1 I Inching Circuit, HST ...............................................................T2-4-30 Inching Operation ..................................................................T2-2-18 Inching Valve (Declutch Valve) ............................................ T3-9-2 J Joystick Type Pilot Valve for Front Attachment (Option)...T311-1

Oil Filter ......................................................................................T3-9-10 ON/OFF Solenoid Valve ........................................................T3-6-10 Operational Principle .............................................................. T3-1-3 Outline.......................................................................................... T3-1-1 Outline (Hydraulic Operated Type) (Option) ................T3-2-13 Outline (Manually Operated Type) ..................................... T3-2-1 Outline of Brake Circuit ........................................................T2-4-37 Outline of Clutch Circuit ......................................................T2-4-33 Overheat Alarm Control .......................................................T2-3-17 Overheat Prevention Control .............................................T2-2-32 Overload Relief Valve ............................................................T3-2-22 Overload Relief Valve (Bucket: Rod Side) ......................... T3-2-8 Overload Relief Valve, Ride Control Valve ......................T3-10-8 Overrun Limit Control ...........................................................T2-2-28

P Parking Brake ............................................................................. T3-6-4 Parking Brake Circuit .............................................................T2-4-40 Parking Brake Circuit .............................................................T2-5-68 Parking Brake Operation Indicator Control...................T2-2-50 Parking Brake Solenoid Valve ............................................... T3-6-9 Pilot Accumulator (Option) ................................................... T3-9-6 Pilot Circuit (Only Hydraulic Operated Type) (Option) ...T2-4L 44 Lift Arm Circuit ........................................................................T2-4-14 Pilot Shut-Off Circuit (Key Switch: ON) (Hydraulic Operated Lift Arm Float Control (Hydraulic Pilot Type) (Option)T2-2-60 Type)(Option) .....................................................................T2-5-24 Lift Arm Kickout Control (Hydraulic Pilot Type) (Option)T2-2- Pilot Shut-Off Solenoid Valve (Hydraulic Operated Type: 62 Option)..................................................................................T1-2-17 Light Bulb Check Circuit (Key Switch: ON).....................T2-5-10 Pilot Shut-Off Solenoid Valve (Option) ............................. T3-9-3 Light Circuit ..............................................................................T2-5-48 Pilot Valve ..................................................................................T3-11-1 Light/Horn Circuit ..................................................................T2-5-47 Pilot Valve, Electromagnetic Detent ............................. T3-11-10 Limited Slip Differential (LSD) (Option) ............................ T3-7-8 Pilot Valve, Operation......................................................... T3-11-12 Low-Pressure Relief Valve ....................................................T3-1-22 Pilot Valve, Operation......................................................... T3-11-18 LSD (Option) ............................................................................... T3-7-8 Pilot Valve, Operation............................................................T3-11-3 Pilot Valve, Outline .................................................................T3-11-1 M Pilot Valve, Outline .............................................................. T3-11-11 Main Circuit, Electrical ............................................................ T2-5-2 Pilot Valve, Outline .............................................................. T3-11-17 Main Circuit, Hydraulic ........................................................... T2-4-2 Preheating Circuit (Key Switch: ON) ................................T2-5-12 Main Component (Overview) .............................................. T1-2-1 Priority Valve ............................................................................T1-2-14 Main Component (Travel System) ...................................... T1-2-2 Priority Valve Circuit (Neutral) .............................................. T2-4-6 Main Pump, Brake/Transmission Pump ..........................T3-1-24 Priority Valve, Operation ........................................................ T3-3-2 Main Relief Valve .....................................................................T3-2-20 Priority Valve, Outline.............................................................. T3-3-1 Main Relief Valve ....................................................................... T3-2-6 Propeller Shaft ........................................................................... T3-9-1 Monitor Panel ............................................................................ T1-2-9 Pump Device Motor Displacement Angle Control .................................. T3-5-6 Pump Device ............................................................................T1-2-11 K JKey Switch: ACC....................................................................... T2-5-8 Key Switch: OFF ......................................................................... T2-5-4 Key Switch: ON .................... T2-5-10, T2-5-12, T2-5-16, T2-5-24 Key Switch: START ..................................................................T2-5-14

N Neutral, Steering Valve ........................................................... T3-4-5 Neutral Circuit..........................................................................T2-4-14 Neutral Circuit, HST................................................................T2-4-24 Neutral Engine Start Control ..............................................T2-3-12 O

R Rear Cab Light Circuit ...........................................................T2-5-44 Rear Console .............................................................................. T1-2-8 Rear Washer Circuit ................................................................T2-5-38 Rear Wiper Circuit ...................................................................T2-5-40 Rear Wiper, Washer Circuit ..................................................T2-5-42 Regulator Operation .............................................................T2-5-18 Regulator, HST Motor .............................................................. T3-5-5 Relays ............................................................................................ T1-2-4 60Z7 F&S

INDEX

Relief Circuit .............................................................................T2-4-14 Reverse Circuit, HST ...............................................................T2-4-28 Ride Control Accumulator (Option) ................................... T3-9-7 Ride Control Circuit (Option) ..............................................T2-4-42 Ride Control Function (Option) .........................................T2-2-48 Ride Control Hydraulic Circuit ...........................................T3-10-2 Ride Control Valve (Option) ................................................T1-2-15 Ride Control Valve, Layout ..................................................T3-10-3 Ride Control Valve, Operation............................................T3-10-3 Ride Control Valve, Outline .................................................T3-10-1 Right Console............................................................................. T1-2-7

Travel Mode Selector Valve ................................................... T3-6-6 Travel Motor ............................................................................... T3-5-4 Travel Slow Mode Selector Circuit ....................................T2-4-34 Traveling ....................................................................................T2-2-14 Turn Signal Light Circuit.......................................................T2-5-58 W Wiper/Washer Circuit ............................................................T2-5-30 Work Light Circuit...................................................................T2-5-54

S S Position, Light SW ...............................................................T2-5-48 Secondary Steering Block (Option)..................................T1-2-16 Secondary Steering Check Block (Option) ...................... T3-9-8 Secondary Steering Circuit (OPT) .....................................T2-4-12 Secondary Steering Control (Option) .............................T2-2-52 Secondary Steering Pump (Option) ................................T1-2-16 Secondary Steering Pump (Option) .................................. T3-9-9 Service Brake ............................................................................T3-7-10 Service Brake Circuit ..............................................................T2-4-38 Single Operation Circuit.......................................................T2-4-14 Single Operation Circuit.......................................................T2-4-16 Slow speed mode ..................................................................... T3-6-3 Solenoid Valve ........................................................................... T3-6-9 Specifications ............................................................................. T1-1-1 Steering (Left) ............................................................................ T3-4-4 Steering (Right) ......................................................................... T3-4-5 Steering Circuit.......................................................................... T2-4-4 Steering Circuit (Right Turn) ................................................. T2-4-8 Steering Stop Circuit .............................................................T2-4-10 Steering Valve, Operation ...................................................... T3-4-3 Steering Valve, Outline ........................................................... T3-4-1 Steering Valve, Structure ....................................................... T3-4-2 Stopping ....................................................................................T2-2-16 Surge Voltage Prevention Circuit......................................T2-5-20 T TCD3.6 L4, Engine Performance Curve ............................. T1-3-4 Torque Proportioning Differential (TPD).......................... T3-7-6 TPD ................................................................................................ T3-7-6 Traction Control ......................................................................T2-2-26 Traction Force Limit Control ...............................................T2-2-24 Transmission ............................................................................T1-2-12 Transmission Circuit ..............................................................T2-4-33 Transmission Control ............................................................T2-2-38 Transmission Control System Layout ..............................T2-2-38 Transmission Lubrication Circuit ......................................T2-4-34 Transmission, Operation ........................................................ T3-6-2 Transmission, Outline ............................................................. T3-6-1 Travel Control Solenoid Valve .............................................. T3-5-8 Travel Fast Mode Selector Circuit .....................................T2-4-34 Travel Mode Selector Solenoid Valve ................................ T3-6-9

60Z7 F&S

INDEX

60Z7 F&S