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Spherical Plain Bearings - Mounting and Fitting

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Mounting Spherical Plain Bearings

To facilitate mounting, the ends of pins or shafts and the edges of housing bores for spherical plain bearings should have a lead chamfer of 10° to 20°.  The bearings can be more easily pressed into position and there is little risk of damage to the mating surfaces being caused by skewing of the bearing.

When mounting spherical plain bearings with a fractured or two-part outer ring, it is essential that the joint should be positioned at 90⁰ to the main load direction; otherwise the service life will be shortened, particularly under heavy loads. Also, the bearing’s lubrication holes will be placed in the load zone, allowing lubricant distribution where it is needed most.

Bearing rings should NEVER be hammered into place. Only apply mounting forces onto the ring that is being mounted (i.e. force on outer ring if being pressed into a housing, force on inner ring if pressed onto a shaft). NEVER apply mounting forces though the bearing’s sliding surfaces, this will damage the bearing and will severely decrease its service life. In the event that the bearing has a press fit on both the inner and outer rings, a special tool should be made to allow pressing of both components simultaneously.

Other ways of mounting with the facilitation of heat or refrigeration, or with the use of adhesives may be possible also, please contact AST Engineering for further assistance.

Fitting

Generally, outer rings of Spherical Plain bearings get press fit into housings. This allows the fracture to remain closed, and prevents rotation of the outer ring under heavy rotational or oscillating loads. Inner rings may have interference or clearance fits on shafts depending on the application. Below is a list of suggested fits for various conditions. Please contact AST Engineering for any further assistance needed.

Fits for Radial Spherical Plain Bearings

The following charts show the various fits for radial spherical plain bearings including: shaft and housing fits along with shaft diameter and housing bore tolerances.

Shaft Fits for Radial Spherical Plain Bearings

Operating Conditions
Sliding Contact Surface Combination
Requiring Maintenance
Maintenance-Free
Loads of all kinds
clearance or transition fit
h6
 hardened shaft ≥45Hrc
h6,g6
Loads of all kinds
interference fit
m6
k6

Housing Fits for Radial Spherical Plain Bearings

Operating Conditions 
Sliding Contact Surface Combination 
Requiring Maintenance 
Maintenance-Free 
Light loads Axial displacement required 
H7 
H7 
Heavy loads 
M7 
K7 
Light alloy housings 
N7 
M7 

Shaft Diameter Tolerances for Radial Spherical Plain Bearings

 
Shaft Diameter Tolerances (µm)
Shaft Diameter (mm)
g6 
h6 
k6 
m6 
 Over
Incl.
High 
Low 
High 
Low 
High 
Low 
High 
Low 
3
6
-4
-12
0
-8
9
1
12
4
6
10
-5
-14
0
-9
10
1
15
6
10
18
-6
-17
0
-11
12
1
18
7
18
30
-7
-20
0
-13
15
2
21
8
30
50
-9
-25
0
-16
18
2
25
9
50
80
-10
-29
0
-19
21
2
30
11
80
120
-12
-34
0
-22
25
3
35
13
120
180
-14
-39
0
-25
28
3
40
15
180
250
-15
-44
0
-29
33
4
46
17
250
315
-17
-49
0
-32
36
4
52
20
315
400
-18
-54
0
-36
40
4
57
21
400
500
-20
-60
0
-40
45
5
63
23
500
630
-22
-66
0
-44
44
0
70
26
630
800
-24
-74
0
-50
50
0
80
30

Housing Bore Tolerances for Radial Spherical Plain Bearings

Housing Bore Diameter (mm)
Housing Bore Tolerances (µm)
H7 
K7 
M7 
N7 
 Over
 incl.
Low 
High 
Low 
High 
Low 
High 
Low 
High 
10
18
0
18
-12
6
-18
0
-23
-5
18
30
0
21
-15
6
-21
0
-28
-7
30
50
0
25
-18
7
-25
0
-33
-8
50
80
0
30
-21
9
-30
0
-39
-9
80
120
0
35
-25
10
-35
0
-45
-10
120
150
0
40
-28
12
-40
0
-52
-12
150
180
0
40
-28
12
-40
0
-52
-12
180
250
0
46
-33
13
-46
0
-60
-14
250
315
0
52
-36
16
-52
0
-66
-14
315
400
0
57
-40
17
-57
0
-73
-16
400
500
0
63
-45
18
-63
0
-80
-17
500
630
0
70
-70
0
-96
-26
-114
-44
630
800
0
80
-80
0
-110
-30
-130
-50
800
1000
0
90
-90
0
-124
-34
-146
-56
1000
1250
0
105
-105
0
-145
-40
-171
-66

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