GROUP 13 EPPR VALVE 1. PUMP EPPR VALVE 1) COMPOSITION EPPR (Electro Proportional Pressure Reducing) valve consists of electro magnet and spool valve installed at main pump. (1) Electro magnet valve Receive electric current from MCU and move the spool proportionally according to the specific amount of electric current value. (2) Spool valve Is the two way direction control valve for pilot pressure to reduce main pump flow. When the electro magnet valve is activated, pilot pressure enters into flow regulator of main pump. (3) Pressure and electric current value for each mode Pressure kgf/cm2
psi
Electric current (mA)
P
7
100
280 ± 30
1950 ± 50
S
10 ± 3
142 ± 40
320 ± 30
1750 ± 50
E
15 ± 3
213 ± 40
400 ± 30
1600 ± 50
P
0
0
160 ± 30
1950 ± 50
S
7±3
100 ± 40
280 ± 30
1850 ± 50
E
12 ± 3
171 ± 40
350 ± 30
1700 ± 50
Mode
Standard (Stage : 1.0)
Option (Stage : 2.0)
Engine rpm (at accel dial 10)
2) HOW TO SWITCH THE STAGE (1.0 ↔ 2.0) ON THE CLUSTER You can switch the EPPR valve pressure set by selecting the stage (1.0 ↔ 2.0). - Management ·Service menu
21093CD67M
Enter the password
21093CD67N
21093CD67P
21093CD67ZZ
· Power shift (standard/option) : Power shift pressure can be set by option menu.
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3) OPERATING PRINCIPLE (pump EPPR valve) (1) Structure 7
6 3
2
4
5
1 5-22(1)
1 2 3
Sleeve Spring Spool
P
4 5
A
T
P T A
O-ring O-ring
6 7
Solenoid valve Connector
Pilot oil supply line (pilot pressure) Return to tank Secondary pressure to flow regulator at main pump
eutral (2) Neutral Pressure line is blocked and A oil returns to tank. P
A P
T
T A
perating (3) Operating Secondary pressure enters into A.
P
A
T P
T A 5-22(2)
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4) EPPR VALVE CHECK PROCEDURE
Spec : 100~700 mA
(1) Check electric current value at EPPR valve
Adapter(P/no.:21Q6-50410)
① Disconnect connector CN-75 from EPPR valve.
CN-75
Multimeter
② Insert the adapter to CN-75 and install multimeter as figure. ③ Start engine.
EPPR valve
④ Set S-mode and cancel auto decel mode. ⑤ Position the accel dial at 10.
Main pump
⑥ If tachometer show approx 1750±50 rpm disconnect one wire harness from EPPR valve.
21095MS21
⑦ Check electric current at bucket circuit relief position. (2) Check pressure at EPPR valve
Spec : 2~25 kgf/cm2 (30~350 psi)
① Remove plug and connect pressure gauge as figure. ·Gauge capacity : 0 to 50 kgf/cm2 (0 to 725 psi)
Pilot pressure supply line
Pressure adjusting screw locknut CN-75
② Start engine. ③ Set S-mode and cancel auto decel mode. EPPR valve
④ Position the accel dial at 10. ⑤ If tachometer show approx 1750±50 rpm check pressure at relief position of bucket circuit by operating bucket control lever.
Main pump
⑥ If pressure is not correct, adjust it.
2107A5MS13
⑦ After adjust, test the machine.
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2. BOOM PRIORITY EPPR VALVE 1) COMPOSITION The boom priority EPPR valve is built in a manifold and mainly consisting of valve body and coil. This EPPR valve installed under the solenoid valve. 2) CONTROL The boom priority EPPR valve has to be controlled by a specific electronic amplifier card, which is supplying the coil with a current 580 mA at 30â„Ś and 24 V. 3) OPERATING PRINCIPLE (1) Structure 1
5
4
6
A P
T
2 Control spool
3 21095MS14
P T
1 2
O-ring Support ring
A
P : Pilot supply line T : Return to tank A : Secondary pressure to flow MCV
3 4
Valve body Coil
5 6
Connector Cover cap
(2) Operation In de-energized mode the inlet port (P) is closed and the outlet port (A) is connected to tank port (T). In energized mode the solenoid armature presses onto the control spool with a force corresponding to the amount of current. This will set a reduced pressure at port A. The setting is proportional to the amount of current applied. (3) Maximum pressure relief If a pressure from outside is applied on port A the valve may directly switch to tank port (T) and protect the system before overload.
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2) EPPR VALVE CHECK PROCEDURE
Spec : 400~600 mA (combined boom up and swing operation)
(1) Check electric current value at EPPR valve
Solenoid valve
① Disconnect connector CN-133 from EPPR valve. ② Insert the adapter to CN-133 and install multimeter as figure.
Boom priority EPPR valve
③ Start engine. ④ If rpm display approx 1750±50 rpm disconnect one wire harness from EPPR valve.
CN-133
⑤ Check electric current in case of combined boom up and swing operation.
Multimeter
Adapter (P/no.:21Q6-50410) 21095MS15
(2) Check pressure at EPPR valve
Spec : 12~37 kgf/cm2 (170~530 psi) (bucket relief operation)
① Remove hose from A5 port and connect pressure gauge as figure. ·Gauge capacity : 0 to 50 kgf/cm2 (0 to 725 psi)
Pressure gauge A5
② Start engine. ③ If rpm display approx 1750±50 rpm check pressure at relief position of bucket circuit by operating bucket control lever.
Solenoid valve Boom priority EPPR valve
④ If pressure is not correct, adjust it. ⑤ After adjust, test the machine.
21095MS16
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