Design considerations

Free space on both sides of the bearing

Where NN design bearings fitted with window-type or pin-type cages are used, free space must be provided on both sides of the bearing (fig. 1) to enable axial displacement of the shaft relative to the housing. The required width of free space can be obtained using

Ca = 1,3 smax

where

Caminimum width of space required on both sides of the bearing [mm]
smaxpermissible axial displacement from the normal position of one bearing ring relative to the other [mm] (→ product table)

Flange support

Where cylindrical roller bearings are subjected to axial loads, total axial run-out (→ Tolerances for bearing seats and abutments) and the size of the abutment surfaces of adjacent components are particularly important for an even load distribution on the flange.
The inner ring flange should only be supported up to half of its height (fig. 2) so that it is not subjected to damaging alternating stresses that can result, for example, from shaft deflection.

The recommended shaft abutment diameter can be obtained using

das = 0,5 (d1 + F)

where
das
shaft abutment diameter for axially loaded bearings [mm]
d1
inner ring flange diameter [mm] (→ product table)
F
inner ring raceway diameter [mm] (→ product table)
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