OK shaft couplings
Contents 3 4 6 7 8 8 9 10 11 12 13 14 15 15 16 16 17 17 18 20 20 21 21 22
The clever connection The OK coupling explained OKC 100 - 190 OKC 200 - 400 OKC 410 - 490 OKC 500 - 520 OKC 530 - 1000 OKF 100 - 300 OKF 310 - 700 OKCS 178 - 360 OKTC 245 - 790 Tailor-made OK couplings Power transmission capacity Safety factors Shafts Conversion tables Hollow shafts for OKC Hollow shafts for OKCS and OKF Modular equipment for mounting and dismounting Oil Approved by leading classification societies Locating device for outer sleeve Mounting arrangements for OKC couplings The Supergrip bolt cuts down on downtime
The clever connection When using the OK couplings for shaft connections, you take advantage of our powerful oil injection method. Preparation of the shaft is simple. No keyways to machine, no taper and no thrust ring. When mounting the OK coupling, a thin inner sleeve with a tapered outer diameter slides onto the shaft. A thick outer sleeve with a matching tapered inner surface fits onto the inner sleeve. Ordinary mineral oil is then injected between the sleeves. A built-in hydraulic jack drives the outer sleeve up the taper of the inner sleeve. When the outer sleeve has reached its final position an interference fit is created – just as if the outer sleeve had been heated and shrunk on. But no heat is required, and the coupling can be removed as easily as it was mounted. This powerful use of friction enables the OK coupling to transmit torque and axial loads over the entire area of the shaft. There are no stress raisers at the keyway. And no fretting when high shock or reversing loads exist.
Make it the clever way! Let the OK coupling work for you. You’ll save both time and money!
3
The OK couplings explained With the OKC and OKF couplings SKF presents benefits impossible to achieve with traditional couplings. The simplicity of mounting and dismounting and the high torque transmission capacity characterised by the OK couplings are achieved using a powerful friction joint. The five stages below illustrate the principle. Up to 2011 more than 40 000 couplings have been delivered for use in many various applications. The OKC coupling (see figure 1 on page 5) has been on the market since the early 40s. OKC couplings are the standard with many well-known controllable pitch propeller manufacturers in the world, but are also used for other applications such as rolling mills, pumps, diesel engines, etc. The OKCS coupling evolved from a special design for engine builders where the torque requirements were less stringent compared to the shaft diameter.
The OKF coupling (see figure 2 on page 5) was developed to create a simple connection between a cylindrical shaft and engines or gearboxes having a flanged at the thrust shaft. The OKF coupling is available with or without a built-in tool for mounting/ dismounting. Since the coupling is mounted on a cylindrical shaft and not fixed by keyways, it can easily be adjusted axially and rotated to the desired position. The OK coupling’s higher torque capacity is obtained due to the entire contact surface transmitting torque as opposed to conventional couplings. Since there is no need for keyways, the dimensions of the shafts and the couplings can be reduced. The OK coupling assures a simplified mounting and dismounting procedure. Very large couplings, which previously could only be shrunk on after heating, can now be assembled cold with the OK method.
Typical installation with OKC and OKF for a propeller shaft line.
‘
4
When oil has drained from the contact surfaces of the two sleeves and friction has been restored, low pressure B is released. All oil connections are plugged. The exposed parts of the coupling should be covered with a rust preventive and the coupling is ready for years of trouble-free operation.
A
A
A
‘
‘
B
‘
5.
The coupling has reached its final position when the outer diameter of the coupling has grown by a predetermined value. The oil pump is stopped, but pressure in B must remain. Pressure in A is released.
A
‘
4.
B
‘
When there is a good oil film between the sleeves, oil leaks out at the thick end of the inner sleeve. Oil is pumped into B and the outer sleeve starts moving up the taper. Oil is continuously injected between the sleeves (A), in order to avoid metallic contact.
A
‘
3.
A
‘
Oil is injected into A under high pressure, building up an oil film between the inner and outer sleeves, eliminating metallic contact and reducing friction forces.
A
‘
2.
B
‘
The coupling is put into position. High pressure injectors are connected to A, and a low pressure to the hydraulic chamber B.
‘
1.
‘
And this is what happens...
A
Fig. 1 The OKC coupling.
Fig. 2 The OKF coupling.
5
Shaft couplings
OKC 100 – 190 Couplings in sizes OKC 180 – OKC 190 are provided with two injection holes A1 BSP 1/4”
A3
BSP 3/4”
A2 D
da h7/E7
A
BSP 1/4” = G 1/4 BSP 3/4” = G 3/4
Designation1)
da mm
D mm
A mm
A1 mm
A2 mm
A32) mm
D3) mm
Mass kg
OKC 100 OKC 110 OKC 120
100 110 120
170 185 200
275 296 322
260 280 300
108 118 130
8 8 10
0,16 0,17 0,18
30 38 48
26,0 34,6 44,9
OKC 130 OKC 140 OKC 150
130 140 150
215 230 250
344 373 396
325 350 370
140 150 162
10 10 12
0,21 0,23 0,23
58 71 91
57,1 71,3 87,7
OKC 160 OKC 170 OKC 180
160 170 180
260 280 300
420 442 475
395 415 445
172 182 195
12 12 15
0,27 0,27 0,28
101 125 155
107 128 152
OKC 190
190
310
505
475
205
15
0,31
175
179
1)
Couplings for shafts of intermediate diameters are, for instance, designated OKC 148.
2)
May be slightly greater or smaller when D is reached, depending on how the tolerance of coupling seatings and coupling bore have been used.
3)
Increase of outer diameter, D, after mounting.
4)
The safety factor referred to on page 15 must be applied to obtain the permissible torque.
Note: Required free length on one shaft for installation A + 75 mm.
6
Mt max.4) kNm
Shaft couplings
OKC 200 – 400 Couplings OKC 300 – OKC 490 have threaded holes for lifting at both ends. Thread OKC A3
A1 BSP 3/4”
BSP 1/4”
A4
300 – 380: M20 x 2,5 390 – 440: M24 x 3 450 – 490: M30 x 3,5
G
A2 D
A
da h7/E7
BSP 1/4” = G 1/4 BSP 3/4” = G 3/4
Designation1)
da mm
D mm
A1 mm
A2 mm
A32) mm
A4 mm
D3) mm
G
OKC 200 OKC 210 OKC 220
200 210 220
330 340 360
525 550 575
500 520 540
215 225 235
15 15 15
30 30 30
0,31 0,35 0,35
M12-(4x) M12-(4x) M12-(4x)
215 230 265
208 241 277
OKC 230 OKC 240 OKC 250
230 240 250
370 390 400
600 620 645
565 585 610
250 260 270
20 20 20
30 30 30
0,38 0,38 0,41
M12-(4x) M12-(4x) M12-(4x)
285 330 350
317 360 407
OKC 260 OKC 270 OKC 280
260 270 280
420 440 450
670 690 715
635 655 680
280 290 300
20 20 20
30 30 30
0,42 0,42 0,46
M12-(4x) M12-(4x) M12-(4x)
410 470 510
457 512 571
OKC 290 OKC 300 OKC 310
290 300 310
470 480 500
740 773 793
700 730 750
315 325 335
25 25 25
30 27 27
0,46 0,50 0,50
M12-(4x) M16-(4x) M16-(4x)
580 625 700
634 702 775
OKC 320 OKC 330 OKC 340
320 330 340
520 530 550
818 843 863
770 795 815
345 355 365
25 25 25
27 27 27
0,50 0,54 0,54
M16-(4x) M16-(4x) M16-(4x)
790 830 930
852 935 1 020
OKC 350 OKC 360 OKC 370
350 360 370
560 580 600
888 908 928
840 860 880
375 385 395
25 25 25
27 27 27
0,57 0,58 0,58
M16-(4x) M16-(4x) M16-(4x)
980 1 080 1 190
1 120 1 220 1 320
OKC 380 OKC 390 OKC 400
380 390 400
610 630 640
958 983 1 003
905 925 950
410 420 430
30 30 30
27 27 27
0,61 0,62 0,65
M16-(4x) M16-(4x) M16-(4x)
1 250 1 370 1 440
1 430 1 550 1 670
A mm
1)
Couplings for shafts of intermediate diameters are, for instance, designated OKC 148.
2)
May be slightly greater or smaller when D is reached, depending on how the tolerance of coupling seatings and coupling bore have been used.
3)
Increase of outer diameter, D, after mounting.
4)
The safety factor referred to on page 15 must be applied to obtain the permissible torque.
Mass kg
Mt max.4) kNm
Note: Required free length on one shaft for installation A + 75 mm.
7
Shaft couplings
OKC 410 – 490 Designation1)
da mm
D mm
A mm
A1 mm
A2 mm
A32) mm
A4 mm
D3) mm
G
Mass kg
Mt max.4) kNm
OKC 410 OKC 420 OKC 430
410 420 430
660 680 690
1 028 1 053 1 073
975 995 1 015
440 450 460
30 30 30
27 27 27
0,66 0,67 0,69
M16-(4x) M16-(4x) M16-(4x)
1 580 1 730 1 800
1 800 1 930 2 070
OKC 440 OKC 450 OKC 460
440 450 460
710 720 740
1 098 1 123 1 148
1 040 1 065 1 085
470 485 495
30 35 35
27 27 27
0,69 0,74 0,74
M16-(4x) M16-(4x) M16-(4x)
1 960 2 050 2 200
2 220 2 370 2 530
OKC 470 OKC 480 OKC 490
470 480 490
750 760 780
1 170 1 195 1 215
1 110 1 135 1 155
505 515 525
35 35 35
27 27 27
0,77 0,80 0,81
M16-(4x) M16-(4x) M16-(4x)
2 290 2 360 2 530
2 700 2 880 3 060
1) 2)
3) 4)
Couplings for shafts of intermediate diameters are, for instance, designated OKC 299. May be slightly greater or smaller when D is reached, depending on how the tolerance of coupling seatings and coupling bore have been used. Increase of outer diameter, D, after mounting. The safety factor referred to on page 15 must be applied to obtain the permissible torque.
Note: Required free length on one shaft for installation A + 75 mm.
Shaft couplings
OKC 500 – 520 A1 BSP 1/4” BSP 1/2”
A4
Couplings OKC 500 – OKC 1000 have threaded holes for lifting at both ends Thread OKC 500 – 520: M30 x 3,5 530 – 610: M36 x 4 620 – 690: M42 x 4,5 700 – 770: M48 x 5 780 – 1000: M64 x 6
A3 BSP 3/4” G
A2 D
A
da h7/E7
BSP 1/4” = G 1/4 BSP 3/4” = G 3/4 BSP 1/2” = G 1/2 Designation1)
da mm
D mm
A mm
A1 mm
A2 mm
A32) mm
A4 mm
D3) mm
G
Mass kg
Mt max.4) kNm
OKC 500 OKC 510 OKC 520
500 510 520
790 810 830
1 240 1 265 1 290
1 175 1 200 1 225
535 545 560
35 35 40
42 42 42
0,84 0,86 0,86
M20-(4x) M20-(4x) M20-(4x)
2 610 2 820 3 060
3 250 3 450 3 660
8
Shaft couplings
OKC 530 – 1000 Designation1)
da mm
D mm
A mm
A1 mm
A2 mm
A32) mm
A4 mm
D3) mm
G
Mass kg
Mt max.4) kNm
OKC 530 OKC 540 OKC 550
530 540 550
840 860 870
1 315 1 340 1 360
1 250 1 275 1 295
570 580 590
40 40 40
42 42 42
0,89 0,89 0,93
M20-(4x) M20-(4x) M20-(4x)
3 140 3 400 3 520
3 870 4 100 4 330
OKC 560 OKC 570 OKC 580
560 570 580
890 900 920
1 385 1 405 1 425
1 315 1 335 1 360
600 610 620
40 40 40
42 42 42
0,93 0,97 0,96
M20-(4x) M20-(4x) M20-(4x)
3 760 3 840 4 150
4 570 4 820 5 080
OKC 590 OKC 600 OKC 610
590 600 610
930 940 960
1 455 1 480 1 500
1 385 1 410 1 430
635 645 655
45 45 45
42 42 42
0,99 1,02 1,03
M20-(4x) M20-(4x) M20-(4x)
4 270 4 400 4 680
5 340 5 620 5 900
OKC 620 OKC 630 OKC 640
620 630 640
970 990 1 010
1 525 1 545 1 570
1 455 1 475 1 495
665 675 685
45 45 45
42 42 42
1,06 1,06 1,07
M20-(4x) M20-(4x) M20-(4x)
4 840 5 140 5 460
6 200 6 500 6 820
OKC 650 OKC 660 OKC 670
650 660 670
1 020 1 040 1 050
1 595 1 625 1 650
1 520 1 545 1 575
695 710 720
45 50 50
42 42 42
1,10 1,11 1,14
M20-(4x) M20-(4x) M20-(4x)
5 620 5 940 6 150
7 140 7 480 7 820
OKC 680 OKC 690 OKC 700
680 690 700
1 070 1 080 1 090
1 670 1 695 1 720
1 590 1 615 1 640
730 740 750
50 50 50
42 42 42
1,14 1,18 1,21
M20-(4x) M20-(4x) M20-(4x)
6 480 6 670 6 830
8 180 8 540 8 920
OKC 710 OKC 720 OKC 730
710 720 730
1 100 1 120 1 130
1 745 1 765 1 790
1 665 1 680 1 700
760 770 785
50 50 55
42 42 42
1,24 1,25 1,28
M20-(4x) M20-(4x) M20-(4x)
7 010 7 390 7 550
9 310 9 700 10 100
OKC 740 OKC 750 OKC 760
740 750 760
1 150 1 160 1 180
1 815 1 835 1 860
1 730 1 750 1 770
795 805 815
55 55 55
42 42 42
1,28 1,32 1,32
M20-(4x) M20-(4x) M20-(4x)
7 990 8 180 8 660
10 600 11 000 11 400
OKC 770 OKC 780 OKC 790
770 780 790
1 190 1 210 1 220
1 886 1 910 1 930
1 795 1 815 1 840
825 835 845
55 55 55
42 42 42
1,36 1,36 1,39
M20-(4x) M20-(4x) M20-(4x)
8 860 9 330 9 530
11 800 12 300 12 800
OKC 800 OKC 820 OKC 840
800 820 840
1 240 1 260 1 300
1 960 2 015 2 055
1 865 1 920 1 960
860 880 900
60 60 60
42 42 42
1,39 1,47 1,47
M20-(4x) M20-(4x) M20-(4x)
10 070 10 520 11 560
13 300 14 300 15 400
OKC 860 OKC 880 OKC 900
860 880 900
1 330 1 360 1 390
2 105 2 155 2 200
2 005 2 055 2 100
920 945 965
60 65 65
42 42 42
1,51 1,54 1,58
M20-(4x) M20-(4x) M20-(4x)
12 370 13 230 14 020
16 500 17 700 18 900
OKC 920 OKC 940 OKC 960
920 940 960
1 430 1 460 1 490
2 245 2 295 2 340
2 145 2 190 2 235
985 1 010 1 030
65 70 70
42 42 42
1,59 1,62 1,66
M20-(4x) M20-(4x) M20-(4x)
15 290 16 270 17 270
20 200 21 600 23 000
980 1 000
1 520 1 550
2 385 2 430
2 280 2 325
1 050 1 070
70 70
42 42
1,69 1,73
M20-(4x) M20-(4x)
18 310 19 390
24 400 26 000
OKC 980 OKC 1000 1)
Couplings for shafts of intermediate diameters are, for instance, designated OKC 505.
2)
May be slightly greater or smaller when D is reached, depending on how the tolerance of coupling seatings and coupling bore have been used.
3)
Increase of outer diameter, D, after mounting.
4)
The safety factor referred to on page 15 must be applied to obtain the permissible torque.
Note: Required free length on one shaft for installation A + 100 mm.
9
Flange couplings
OKF 100 – 300 A A1 C
Drive-up length
B
BSP 3/4”
R
BSP 1/4” BSP 3/4”
D1 D
L da h7/F7 L1
BSP 1/4” = G 1/4 BSP 3/4” = G 3/4
Lock levels from size OKF 300
The pitch circle is evaluated from: E = D1 – (1.6 x bolt diameter)
Designation mm
da
D
D1
A
A1
B
R
L
L1
C
Mass
Mt max.1)
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
kg
kNm
OKF 100 OKF 110 OKF 120
100 110 120
165 175 195
235 260 285
191 210 220
188 197 206
40 40 40
8 9 10
120 135 145
15 15 15
17,5 18,5 19,0
25 29 39
26,0 34,6 44,9
OKF 130 OKF 140 OKF 150
130 140 150
205 225 240
305 325 345
244 255 266
230 235 246
40 40 40
10 11 12
165 170 180
15 15 15
21,5 22,0 23,0
46 56 66
57,1 71,3 87,7
OKF 160 OKF 170 OKF 180
160 170 180
255 265 290
365 390 415
278 295 310
257 274 288
40 40 40
13 14 14
195 205 215
15 15 15
24,5 26,0 26,5
77 87 108
107 128 152
OKF 190 OKF 200 OKF 210
190 200 210
295 315 325
435 455 475
338 348 362
311 320 338
40 40 42
15 16 17
230 240 250
18 18 18
29,5 30,0 31,5
118 138 153
179 208 241
OKF 220 OKF 230 OKF 240
220 230 240
345 350 370
495 500 525
378 390 402
353 365 376
44 46 48
18 18 19
265 275 285
18 18 18
31,5 34,5 34,5
180 184 216
277 317 360
OKF 250 OKF 260 OKF 270
250 260 270
380 400 420
555 575 595
418 436 452
392 408 424
50 52 54
20 21 22
300 310 325
18 22 22
36,0 38,0 38,0
238 275 316
407 457 512
r ss
OKF 280 OKF 290 OKF 300
280 290 300
430 445 460
605 620 635
464 476 498
435 447 463
56 58 60
22 23 24
335 345 360
22 22 22
40,0 41,5 42,0
335 364 399
571 634 702
f OKBS 40 s s c
1)
The safety factor referred to on page 15 must be applied to obtain permissible torque.
10
Suitable Supergrip Bolt size
Flange couplings
OKF 310 – 700 Designation OKF 310 OKF 320 OKF 330
da
D
D1
A
A1
B
R
L
L1
C
Mass
Mt max.1)
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
kg
kNm
62 64 66
25 26 26
370 380 395
22 25 25
43,5 44,5 46,5
310 320 330
475 495 505
675 695 705
510 526 544
479 494 512
451 508 537
775 r 852 s 935 s
OKF 340 OKF 350 OKF 360
340 350 360
525 530 550
730 735 760
555 572 584
522 538 550
68 70 72
27 28 29
405 420 430
25 25 25
47,0 49,0 50,0
599 615 680
f s 1 020 s 1 120 s 1 220 c
OKF 370 OKF 380 OKF 390
370 380 390
570 580 600
810 820 840
595 612 624
560 577 588
74 76 78
30 30 31
440 455 465
25 25 25
50,5 51,5 52,5
770 805 885
1 320 r 1 430 s 1 550 f
OKF 400 OKF 410 OKF 420
400 410 420
610 630 640
855 875 890
648 660 672
611 627 639
80 82 84
32 33 34
480 490 500
25 30 30
54,0 55,5 57,5
930 1 030 1 070
s 1 670 s 1 800 s 1 930 c
OKF 430 OKF 440 OKF 450
430 440 450
655 675 685
935 955 970
688 700 716
654 665 681
86 88 90
34 35 36
515 525 540
30 30 30
58,0 58,5 60,5
1 170 1 270 1 330
2 070 r 2 220 s 2 370 s
OKF 460 OKF 470 OKF 480
460 470 480
700 715 720
985 1 000 1 005
728 740 758
692 703 717
92 94 96
37 38 38
550 560 570
30 30 30
61,5 62,5 65,0
1 410 1 480 1 510
2 530 f 2 700 s 2 880 s
OKF 490 OKF 500 OKF 510
490 500 510
740 750 770
1 030 1 040 1 090
770 790 810
728 748 766
98 100 102
39 40 41
580 600 610
30 30 35
66,0 67,0 69,5
1 630 1 700 1 870
3 060 s 3 250 c 3 450 r
OKF 520 OKF 530 OKF 540
520 530 540
790 800 815
1 115 1 125 1 145
820 834 845
776 789 800
104 106 108
42 42 43
620 630 640
35 35 35
70,0 72,0 73,5
2 020 2 080 2 190
OKF 550 OKF 560 OKF 570
550 560 570
825 845 855
1 155 1 175 1 190
868 878 890
822 832 843
110 112 114
44 45 46
660 670 680
35 35 35
74,5 75,0 77,0
2 270 2 420 2 510
s s sf s s 4 330 s 4 570 s 4 820 c
OKF 580 OKF 590 OKF 600
580 590 600
875 885 895
1 235 1 245 1 260
900 914 926
853 866 877
116 118 120
46 47 48
690 700 710
35 35 35
77,0 79,0 81,0
2 710 2 780 2 860
5 080 r 5 340 s 5 620 s
OKF 610 OKF 620 OKF 630
610 620 630
910 920 940
1 275 1 290 1 310
938 950 962
888 900 911
122 124 126
49 50 50
720 730 740
35 35 35
82,0 84,0 84,5
2 880 3 070 3 230
5 900 f 6 200 6 500 s
OKF 640 OKF 650 OKF 660
640 650 660
960 970 990
1 330 990 1 345 1 004 1 395 1 018
938 951 961
128 130 132
51 52 53
760 770 780
40 40 40
85,5 87,5 88,0
3 510 3 600 3 750
6 820 s 7 140 c 7 480 r
OKF 670 OKF 680 OKF 690
670 680 690
995 1 015 1 025
1 410 1 030 1 420 1 042 1 435 1 054
973 984 996
134 136 138
54 54 55
790 800 810
40 40 40
91,0 91,5 93,5
3 930 4 130 4 230
s 7 820 s 8 180 f 8 540 s
OKF 700
700
1 035
1 445 1 068 1 009
140
56
820
40
96,0
4 330
8 920 c
Suitable Supergrip Bolt size
OKBS 50
OKBS 60
s
3 660 3 870 4 100
OKBS 70
OKBS 80
s OKBS 90
s
OKBS 100
s 1)
The safety factor referred to on page 15 must be applied to obtain the permissible torque.
11
Shaft couplings
OKCS 178 – 360 A A1 BSP 1/4”
10
–0 – 0,5
BSP 3/4”
A2 da D h6/F7
F
BSP 1/4” = G 1/4 BSP 3/4” = G 3/4 Designation1)
da mm
D mm
A mm
A1 mm
A2 mm
F mm
Mass kg
Mt max.2) kNm
OKCS 178 OKCS 210 OKCS 214
178 210 214
310 350 365
282 331 345
244 295 308
105 127,5 132
8 8 8
98 166 170
65 110 118,6
OKCS 230 OKCS 250 OKCS 270
230 250 270
400 420 460
348 364 386
315 328 350
134,5 140 149
8 8 8
209 231 300
141 180 225
OKCS 300 OKCS 310 OKCS 330 OKCS 360
300 310 330 360
510 525 560 600
426 446 457 493
385 400 410 455
164 170 177 190
9 9 9 9
406 429 521 635
301,8 338,8 391,5 525
1)
Couplings for shafts of intermediate diameters are, for instance, designated OKCS 215.
2)
The safety factor referred to on page 15 must be applied to obtain the permissible torque
Note: Required free length on one shaft for installation A + 75 mm.
12
Hydraulic rings and propeller nuts
OKTC 245 – 790 L BSP 1/4”
Propeller nut
Propeller nut
Propeller
Propeller nut
Propeller
Propeller
d Ø D1 d1 d2 Ø D2
S
Nut with integrated thread is designated OKTH.
Designation
d mm
D1 mm
d1 mm
d2 mm
D2 mm
L mm
Smax. mm
Max. force kN (at 70 MPa)
Mass kg
OKTC 245 OKTC 265 OKTC 285
260 – 275 275 – 295 295 – 315
245 265 285
275 295 315
340 365 385
390 415 435
55 55 55
15 15 15
2 195 2 540 2 690
31 35 37
OKTC 305 OKTC 325 OKTC 345
315 – 335 335 – 365 365 – 385
305 325 345
335 365 385
415 445 470
465 510 535
55 70 70
15 20 20
3 295 3 560 3 995
42 66 72
OKTC 365 OKTC 385 OKTC 405
385 – 405 405 – 425 425 – 445
365 385 405
405 425 445
495 520 545
560 585 610
70 70 70
20 20 20
4 450 4 935 5 440
77 84 90
OKTC 425 OKTC 445 OKTC 465
445 – 465 465 – 485 485 – 505
425 445 465
465 485 505
570 595 620
635 660 685
70 70 70
20 20 20
5 975 6 530 7 110
96 103 110
OKTC 485 OKTC 505 OKTC 525
505 – 525 525 – 545 545 – 565
485 505 525
525 545 565
645 670 695
710 735 760
70 70 70
20 20 20
7 715 8 350 9 005
116 123 130
OKTC 545 OKTC 565 OKTC 585
565 – 595 595 – 615 615 – 635
545 565 585
595 615 635
725 750 775
805 830 855
90 90 90
25 25 25
9 430 10 130 10 850
195 205 216
OKTC 605 OKTC 625 OKTC 645
635 – 655 655 – 675 675 – 695
605 625 645
655 675 695
800 825 860
880 905 940
90 90 90
25 25 25
11 595 12 370 14 105
226 238 260
OKTC 670 OKTC 690 OKTC 720
695 – 720 720 – 740 740 – 770
670 690 720
720 740 770
885 915 955
965 995 1 050
90 90 100
25 25 30
14 560 15 920 17 545
267 285 360
OKTC 750 OKTC 770 OKTC 790
770 – 800 800 – 820 820 – 840
750 770 790
800 820 840
985 1 010 1 035
1 080 1 105 1 130
100 100 100
30 30 30
18 155 19 115 20 100
372 387 402
This list is designed as a guide. If the ring you require is not listed, please contact your closest distributor, and we will design a ring for you on the receipt of the following information: a. Dimensions of propeller boss. b. Maximum power, kW. c. Speed, r/min. d. Safety factor. e. Modulus of elasticity for boss and shaft respectively, N/mm2. f. Temperature coefficient of linear expansion for boss and shaft respectively. g. Yield point for shaft and boss, N/mm2. If drive-up force and drive-up length is being calculated by customer that information together with the propeller shaft thread and the small inner diameter of the propeller boss only are required. SKF pump 728619 E is recommended for the ring as well as for injecting oil in the propeller hub. For sizes OKTC 505 or larger, an air driven pump, THAP 150 is recommended.
13
Tailor-made OK couplings Besides standard series of OK couplings, SKF Coupling Systems design and manufacture ‘‘tailor-made’’ OK couplings for shaft diameters from 100 mm and up. Some examples:
Flange couplings with oil chamber under the flange and Supergrip bolts combination for limited space
Double sleeve arrangement for bearing installation
Hub for gear couplings
Oil power shrink disc couplings
Double flange couplings
14
Power transmission capacity Torque transmitted by the OKC coupling is directly proportional to the surface pressure between the inner sleeve of the coupling and the shaft after the outer sleeve has been driven up axially. The necessary driveup, which is reached when the diameter of the outer sleeve has increased by dimension D for OKC and OKCS couplings, and the stated drive-up length for OKF couplings given in the tables, will ensure a pressure of 120 N/mm2 for OKC couplings, and 100 N/mm2 for OKF couplings.
If the coupling is subjected to axial forces, their effect on the power transmission capacity is generally insignificant. The transmissible torque is obtained from the equation:
P Mtmax.
The table lists the maximum torque which can be transmitted calculated using the equation:
t F xd y 2 a a s v 2 x 103 b
– a
where:
p . da2 . B . p . µ Mtmax. = 2 .103
Mtmax.
maximum transmissible torque, Nm
Fa
axial force, N
da
shaft diameter, mm
The permissible torque is obtained from:
where: Mtmax.
maximum transmissible torque, Nm
da
shaft diameter, mm
B
effective pressure length (equal to da for OKC) in mm
p
minimum surface pressure between shaft and inner sleeve in N/mm2 – 120 N/mm2 for OKC and OKCS – 100 N/mm2 for OKF
µ
2
Mt =
M=
Mtmax. or Mt f
where M
permissible torque, Nm
Mtmax.
maximum transmissible torque, Nm
Mt
transmissible torque, Nm
f
safety factor, which can be selected from the table below
coefficient of friction (0,14)
Safety factor f at different loads Type of power source
Type of load on the driven machine Uniform load Centrifugal pumps Fans Light conveyors Turbo compressors Agitators
Moderate shock-loads Piston compressors Small piston pumps Cutting tool machines Packeting machines Wood working machines
Heavy shock-loads Excenter presses Draw benches Plane machines Large piston compressors
Electric motor, turbine
2
2,25 – 2,5
2,5 – 2,75
Multiple cylinder piston engine
2,25 – 2,5
2,5 – 2,75
2,75 – 3
Single cylinder piston engine
2,75 – 3
3
3,25 – 4
– 2,25
– 3,25
When the coupling is intended for marine applications, the safety factor has to be selected according to the rules of the referred classification society.
15
Shafts To facilitate shaft alignment for OKC and OKCS couplings one of the shafts should be so designed that the coupling can be slid along it far enough to expose the outermost part of the coupling seating.
Ø da
Surface roughness is to be within Ra 2,5 µm. ISO tolerance h8 applies to coupling seatings from 25 - 90 mm. ISO tolerance h7 is used for larger diameters.
Shaft diameter da over mm
to mm
IT 7 2
Tolerance
Cylindricity tolerance
h7 deviation upper lower µm µm
IT7 2 µm
100 120 180
120 180 250
0 0 0
– 35 – 40 – 46
17,5 20 23
250 315 400
315 400 500
0 0 0
– 52 – 57 – 63
26 28,5 31,5
500 630 800
630 800 1 000
0 0 0
– 70 – 80 – 90
35 40 45
Conversion tables Conversion: millimetre to inch Shaft diameter da Millimetre Inch over to over to
Tolerance h7 deviation Millimetre upper lower
Inch upper
100 120 180
120 180 250
3,937 4,724 7,087
4,724 7,087 9,843
0 0 0
– 0,035 – 0,040 – 0,046
0 0 0
– 0,001378 – 0,001575 – 0,001811
250 315 400
315 9,843 400 12,402 500 15,748
12,402 15,748 19,685
0 0 0
– 0,052 – 0,058 – 0,063
0 0 0
– 0,002047 – 0,002244 – 0,002480
500 630 800
630 19,685 800 24,803 1 000 31,496
24,803 31,496 39,370
0 0 0
– 0,070 – 0,080 – 0,090
0 0 0
– 0,002756 – 0,003150 – 0,003543
Length
1 mm = 0,03937 in 1 in = 25,4 mm
Mass
1 kg = 2,205 lb 1 lb = 0,4536 kg
Force
1 N = 0,225 lbf 1 lbf = 4,45 N
Torque
1 Nmm = 0,00885 in.lbf 1 Nm = 8,85 in.lbf 1 lbf.in = 113 Nmm = 0,113 Nm 1 lbf.ft = 1356,23 Nmm = 1,35623 Nm
Power
1 W = 0,00136 HP 1 HP = 736 W
Pressure
1 MPa = 1 N/mm2 = 145 psi 1 psi = 0,007 N/mm2 = 0,007 MPa
Kinematic viscosity
1 mm2/s = 1 cSt
lower
Temperature 0 °C = 32 °F °F = 1,8 x °C + 32
16
Hollow shafts for OKC couplings The outer sleeve must be driven further up with hollow shafts than with solid ones if the same pressure and power transmission capacity are to be achieved. The shafts must also be reinforced by means of sleeves shrunk into recess turned beneath the coupling seatings. This will prevent the stresses, which arise in the shaft material when the coupling has been mounted, from exceeding the permissible value. The reinforcement sleeve should be made of toughened steel with a yield point of at least 850 N/mm2. The length of the sleeves should be 15 mm longer than the pressure length (= A2 - A3 + 15 mm). The outside diameter, the required interference between the sleeves and the shafts, and the increase in the drive-up distance (the reduction in dimension A3) can be obtained from the table below for various values of diameter ratio dc/da. Suitable tolerance ranges for the outside diameter of the sleeves and the recesses in the shafts are IT6 and IT7 respectively. Note that the coupling seatings should be machined to the prescribed diameter tolerance only after the reinforcement sleeves have been fitted. dc da
db da
d db
R da
0,1 0,15 0,2
0,38 0,41 0,45
0,0006 0,0008 0,0009
0,001 0,002 0,004
0,25 0,3 0,35
0,48 0,49 0,51
0,0011 0,0013 0,0015
0,006 0,009 0,013
0,4 0,45 0,5 0,55
0,54 0,58 0,62 0,67
0,0017 0,0019 0,0021 0,0023
0,018 0,024 0,031 0,040
Example: An OKC coupling is to be mounted on shafts with an outside diameter of 400 mm and a bore of 120 mm. i.e.
dc 120 = = 0,3 da 400
The outside diameter of the reinforcement sleeve is d obtained from b = 0,49, i.e. db = 196 mm. da The interference d is obtained from d = 0,0013, i.e. d = 0,25 mm db The increase in drive-up distance, R, is obtained R from the ratio = 0,009. Thus dimension A3 in da the table on page 7 (30 mm) must be reduced by 3,6 mm.
A3– R
dc db da
With hollow shafts whose diameter ratio exceeds 0,55 the normal pressure and transmitted torque cannot be fully achieved. In such cases, please consult us or your local representative.
Hollow shafts for OKCS and OKF couplings For OKCS and OKF couplings mounted on hollow shafts, please contact your local representative.
17
Modular equipment for mounting and dismounting
TMHK 36 Suitable for OKC 100 - OKC 170 and OKCS 178 - OKCS 360 1 Tool case 728245/3A 1 Oil injector 226400 1 Hand operated pump TMJL 50 1 Set of hex keys 1 Spare parts for injector 226400 Mass: 19 kg
TMHK 37 Suitable for OKC 180 - OKC 250 and OKF 100 - OKF 300 1 Tool case 728245/3A 2 Oil injectors 226400 1 Hand operated pump TMJL 50 1 Pipe 227958A 1 Adapter block 226402 1 Set of hex keys 1 Spare parts for injector 226400 Mass: 28,1 kg Set TMHK 38 can also be used for these coupling sizes. The set contains a hydraulic pump driven by compressed air which enables the coupling to be mounted more quickly.
TMHK 38 Suitable for OKC 180 - OKC 490 and OKF 300 - OKF 700 1 Air-driven pump set THAP 030/SET 1 Return hose 729147A 2 Oil injectors 226400 1 Set of hex keys 1 Spare parts for injector 226400 Mass: 32,1 kg
18
TMHK 38S Suitable for OKC 180 - OKC 490 and OKF 300 - OKF 700 1 Air-driven pump set THAP 030/SET 1 Return hose 729147A 1 Air-driven pump THAP 300E 1 Oil injector 226400 1 Set of hex keys 1 Spare parts for injector 226400 Mass: 78,2 kg including weight of pallet
TMHK 39 Suitable for OKC 500 and larger 1 Air-driven pump set THAP 030/SET 1 Return hose 729147A 3 Oil injectors 226400 1 Set of hex keys 1 Spare parts for injector 226400 Mass: 35,1 kg This set is intended for use on board ship where dismounting and mounting is only carried out infrequently. For shipyards and workshops sets TMHK 40 or TMHK 41 with an air-driven high pressure pump are recommended.
TMHK 40 Suitable for OKC 500 and larger 1 Air-driven pump set THAP 030/SET 1 Return hose 729147A 1 Air-driven pump THAP 300E 2 Oil injectors 226400 1 Set of hex keys 1 Spare parts for injector 226400 Mass: 80,2 kg including weight of pallet This set or also set TMHK 41 are recommended for shipyards and workshops. The air-driven high pressure pump simplifies works considerably.
TMHK 41 Suitable for OKC 500 and larger 1 Air-driven pump set THAP 030/SET 1 Return hose 729147A 3 Air-driven pumps THAP 300E 1 Set of hex keys Mass: 132,7 kg including weight of pallet This pump set is recommended for shipyards and workshops.
19
Oil The mineral motor oil to be used for the pump and the injectors should have a viscosity of 300 mm2/s (300 cSt) at the temperature of the coupling. This viscosity will generally be obtained with sufficient accuracy if the oil is chosen according to the table below. Temperature range
0 – 8 °C 8 – 18 °C 18 – 27 °C 27 – 32 °C 32 – 38 °C
Viscosity
mineral motor oil mineral motor oil mineral motor oil mineral motor oil mineral motor oil
SAE 10 W SAE 20 W SAE 30 W SAE 40 W SAE 50 W
Approved by all leading classification societies Connecting rigid shafts with OK couplings is a timesaving solution that has been usen on land and at sea for more than fifty years. The couplings are well known all over the world for their high quality, creative design and operational safety. In the production line each step is carefully controlled and the finished couplings are subjected to a rigid final inspection regarding dimensions and steel quality before delivery. The couplings are also approved by all major classification societies, for example Det Norske Veritas.
20
Locating device for outer sleeve and nut All OKC couplings for shafts with diameters 200 mm or bigger and OKF couplings for shafts with diameter 300 mm or bigger are equipped with lock levers, which prevent the outer sleeve from being driven up un-
Locating device before mounting
intentionally on the inner sleeve during transport and when the coupling is being mounted or dismounted. The lock levers also lock the nut when the coupling has been installed.
Locating device after mounting
Mounting arrangements for OKC couplings To facilitate the mounting and dismounting of large OKC couplings, it is advisable to use some type of lifting arrangement. The types of arrangements shown will also allow radial shaft alignment. In both cases the carriages should move in line with the shafts.
OPTION I A wheeled carriage is provided with two hydraulic jacks, positioned as shown. This allows the coupling to be adjusted as required.
OPTION II An overhead carriage with two fixed chain blocks is positioned above the coupling. Lifting ropes are positioned as shown giving the required adjustment or lifting eyebolts can be used from size OKC ≤ 400.
21
The Supergrip bolt cuts down on downtime At a time when maintenance cost efficiency in heavy industries is a make-or-break factor in operational economy, the time-saving Supergrip concept can cut costs dramatically. When you connect your couplings with Supergrip bolts, there is no uncertainty about the length of downtime for removing the bolts. No worry about whether the bolts have jammed or seized in the holes. You know that once the tension and expansion pressure have been released, each bolt will slide out as easily as it went in. Ninety percent reduction of downtime A study released by the Swedish State Power Board on the comparison of individually fitted bolts with Supergrip bolts showed a 90 % reduction in the time required to disassemble and reassemble the couplings of two turbo sets (eight couplings). The unit equipped with Supergrip bolts was reconnected to the power grid 48 hours earlier than the unit with conventional bolts. Total savings were 19 200 000 kWh (48 hours x 400 MW). Oil injection method The Supergrip bolts are a superior solution for connecting rotating flange couplings. Compared with traditional bolt systems, Supergrip bolts are easier to install and remove, take much less time and hold the coupling halves together much more securely. The torque in a coupling connected with Supergrip bolts is transmitted in two ways: by shear strength of the expanded bolt in the hole, and by the friction effect at the flange faces created by pre-loading the bolt. Designed specifically for such high-torque applications as propeller shafts, rudder assemblies, turbo generators, the Supergrip bolt offers significant advantages. Simplified machining of the holes and no grinding of the bolts. You eliminate re-reaming and re-honing. The bolts are designed to be inserted and removed with an initial clearance fit. There is no risk of seizure. It is easy to see why we have delivered some 150 000 bolts over the years! For more detailed information and design recommendations, please ask for our Supergrip brochure.
22
The oil injection method used in our OK couplings was developed by us in the early 1940s. Since then more than 40 000 couplings have been supplied to ships, power installations, etc all over the world. The OK couplings are manufactured in modern NC-controlled equipment utilizing CAD/CAM technology. Our most important resource is, however, a well-trained staff with a long experience and tradition of manufacturing precision engineering products.
SKF Coupling Systems AB was established in the early 1940s when SKF’s Chief Designer, Erland Bratt, invented the SKF oil injection method. As the result of continuous development, SKF is currently a world leader in selected market niches. Our business concept is to develop, produce and supply products based on the SKF oil injection method. These products significantly reduce downtime and lower maintenance costs of the capital-intensive equipment in which they are used.
® SKF is a registered trademark of the SKF Group. © SKF Group 2011 The contents of this catalogue are the copyright of the publisher and may not be reproduced (even extracts) unless permission is granted. Every care has been taken to ensure the accuracy of the information contained in this catalogue but no liability can be accepted for any loss or damage whether direct, indirect or consequential arising out of the use of the information contained herein. Publication November 2011 Printed in Sweden on environmentally friendly, chlorine-free paper.
2000
SE-813 82 Hofors, Sweden. Tel: +46 290 284 00. Fax: +46 290 282 70 E-mail: skf.coupling.systems@skf.com Website: www.couplings.skf.com