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Spherical Plain Bearings - Internal Clearance

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Definition of Internal Clearance for Spherical Plain Bearings

Bearing internal clearance for spherical plain bearings is defined as the total distance through which one ring can be moved radially (radial internal clearance) or axially (axial internal clearance) in relation to the other ring under a defined measuring load.

It is necessary to distinguish between the internal clearance of a spherical plain bearing before it is mounted and the internal clearance of a mounted bearing when in operation (operational clearance). The initial clearance will always be greater than the operational clearance because the rings are expanded or compressed by interferences fits and as a result of the differences in thermal expansion of the bearing rings and mating components.

The bearing internal clearance shall be selected so that when bearings are mounted with recommended fits, and operate under normal conditions a suitable operational clearance will be obtained. For other conditions (e.g. where both rings are mounted with an interference fit or where unusual temperatures prevail), bearings with greater or smaller internal clearance than normal may be required.

Radial Internal Clearance Of Radial Spherical Plain Bearings Supplied by AST Bearings

The following data is provided by AST Bearings and is specific to the series of Spherical Plain Bearing Series as indicated by each table.  The data is presented by construction/material types:  Steel-on-Steel, Steel-on-PTFE-Composite, Steel-on-PTFE-Fabric, and Steel-on-Copper-Alloy.

Radial Internal Clearance Of Steel-On-Steel Radial Spherical Plain Bearings

Series GE—E, GE—ES, GE—ES-2RS, GEEW—ES, GEEM—ES-2RS

d (mm) 
Group C2 (µm)
Group normal (µm)
Group C3 (µm)
over
incl.
min 
max 
min 
max 
min 
max 
12 8 32 32 68 68 104
12 20 10 40 40 82 82 124
20 35 12 50 50 100 100 150
35 60 15 60 60 120 120 180
60 90 18 72 72 142 142 212
90 140 18 85 85 165 165 245
140 240 18 100 100 192 192 284
240 300 18 110 110 214 214 318
300 320 18 135 135 261 261 387

Series GEG—E, GEG—ES, GEG—ES-2RS

d (mm) 
Group C2 (µm) 
Group normal (µm)
Group C3 (µm)
over
incl.
min 
max 
min 
max 
min 
max 
10
8
32
32
68
68
104
10
17
10
40
40
82
82
124
17
30
12
50
50
100
100
150
30
50
15
60
60
120
120
180
50
80
18
72
72
142
142
212
80
120
18
85
85
165
165
245
120
160
18
100
100
192
192
284
160
220
18
100
100
192
192
284
220
280
18
110
110
214
214
318

Series GEF—ES

d (mm) 
Group normal (µm)
over incl. min  max 
12
32
68
12
20
40
82
20
35
50
100
35
55
60
120
55
80
72
142
80
120
85
165
120
150
100
192

Series GEBJ—S, GEFZ—S

d (mm) 
Group normal (µm)
over
incl.
min 
max 
8
20
60
8
14
40
90
14
20
50
110
20
35
60
120

Series GEBK—S

d (mm) 
Group normal (µm)
over
RI incl.
min 
max 
30
0
35

Series GE—XS/K

d (mm) 
Group normal (µm)
over RI incl.
min 
max 
15
70
125
15 30
75
140
30 50
85
150
50 65
90
160
65 80
95
170
80 100
100
185
100 120
110
200
120 150
120
215

Series GEZ—ES, GEZ—ES-2RS, GEWZ—ES, GEWZ—ES-2RS

d (mm) 
Group C2 (µm) 
Group normal (µm)
Group C3 (µm)
over
RI incl.
min 
max 
min 
max 
min 
max 
15.875
10
50
50
150
150
220
15.875
50.8
10
80
80
180
180
250
50.8
76.2
30
100
100
200
200
270
76.2
152.4
60
130
130
230
230
300
152.4
203.2
80
180
180
300
300
380
203.2
254
100
200
200
330
330
410
254
304.8
120
230
230
350
350
430

Series GEGZ—ES, GEGZ—ES-2RS

d (mm)
Group C2 (µm)
Group normal (µm)
Group C3 (µm)
over
RI incl.
min
max
min
max
min
max
12.7
44.45
10
80
80
180
180
250
44.45
69.85
30
100
100
200
200
270
69.85
139.7
60
130
130
230
230
300

Series GEC— XS, GEC—XS-2RS

d (mm)
 Group C2 (µm)
 Group normal (µm)
 Group C3 (µm)
 over
RI incl.
min
max
min
max
min
max
300
340
18
125
125
239
239
353
340
420
18
135
135
261
261
387
420
530
18
145
145
285
285
425

Series GEK—XS-2RS

d (mm)
Group normal (µm)
over
RI incl.
min
max
20
35
100
200
35
60
120
250

Radial Internal Clearance Of Steel On PTFE Composite Material Radial Spherical Plain Bearings

Series GEH—HC

d (mm)
Group normal (µm)
over
incl.
min
max
90
120
85
285
120
180
100
335
180
220
100
355
220
240
110
356
240
280
110
380
280
300
135
415
300
320
135
490
320
360
135
490
360
380
135
490
380
400
135
510
400
480
145
550
480
500
145
570
500
600
145
610
600
630
160
640

Series GE—C, GEG—C, GEBJ—C, GEFZ—C

d (mm)
Group C2 (µm)
Group normal (µm)
Group C3 (µm)
over
incl.
min
max
min
max
min
max
12
2
20
4
28
20
55
12
20
3
25
5
35
25
60
20
30
4
30
6
44
30
75
30
50
5
35
7
53
35
80

Radial Internal Clearance Of Steel –On-Fabric And Steel-On-Copper Alloy Radial Spherical Plain Bearings

Series GE— ET-2RS, GE— XT-2RS, GE—ET/X, GE— ET-2RS/X, GE—XT/X, GE—XT-2RS/X, GEZ —ET-2RS, GEC —XT, GEC— XT-2RS, GEC— HT, GEFZ— T, GE—N

d (mm)
Group C2 (µm)
Group normal (µm)
Group C3 (µm)
over
incl.
min
max
min
max
min
max
20
0
30
0
40
30
60
20
35
0
35
0
50
35
65
35
60
0
40
0
60
40
80
60
90
0
50
0
72
50
90
90
140
0
60
50
130
95
145
140
180
0
70
50
140
110
160
180
300
0
80
80
190
160
220
300
340
18
125
125
239
239
353
340
420
18
135
135
261
261
387
420
600
18
145
145
285
285
425

Series GEG —2RS, GEG —XT-2RS

d (mm)
Group normal (µm)
over
inch
min
max
30
0
50
30
50
0
60
50
80
0
72
80
120
0
85
120
220
0
100
220
280
0
110

Series GEH— XT GEH— XT-2RS GEH—HT GE— XF/Q GEC—XF/Q GEH— XF/Q GEH—HF/Q

d (mm)
Group normal (µm)
over
incl.
min
max
90
120
85
165
120
180
100
192
180
240
110
214
240
300
125
239
300
380
135
261
380
480
145
285
480
600
160
320
600
750
170
350

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