OK shaft couplings

OK shaft couplings
Contents
3
4
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7
8
8
9
10
11
12
13
14
15
15
16
16
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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: [email protected]
Website: www.couplings.skf.com