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Miniature & Small ball bearings -11. Designs of shaft and housing

Please carefully design to optimize the bearing performance with regard to the dimensions and precision of the shaft and housing which contact the bearings when they are installed in the equipment.


Shaft and housing

Finish precision of shaft and housing

When the bearings are installed, roundness of the bearings is degraded if the precision and surface roughness of the shaft and housing are not at satisfactory levels.


Fillet radii of corners of shaft and housing

The side faces of shafts and housings (area contacting bearing side face) come at right angles to the shaft center and fit surface. The maximum permissible radius (ras max) of the fillet radii of the shaft and housing corners is smaller than minimum permissible chamfer dimensions of the bearings.


Height of shoulder

The height of the shaft and housing shoulders must be taller than minimum permissible chamfer dimensions. They also need to contact the side faces of the inner and outer rings.
The minimum height of shoulders is four times taller than minimum permissible chamfer dimensions. Please refer to the table on the right and figure11-1 for dimensions.


Referred from JIS B 1566

unit : μm

Chamfer dimensions of inner and outer ring Shaft and housing
Radii of rounding of corners General case*1 Particular case*2
rs min ras max h (min)
0.05*3 
0.08*3 
0.1 
0.15 
0.2 
0.3
0.05 
0.08 
0.1 
0.15 
0.2 
0.3
0.2 
0.3 
0.4 
0.6 
0.8 
1.25
0.2 
0.3 
0.4 
0.6 
0.8 
1

*1 In the case where a large axial load is applied, the height of the shoulder needs to be taller than this.
*2 It is used in the case where an axial load is small.
*3 It is not specified in JIS B 1566.

Figure11-1

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