Preload is the relationship of the bearing bore to
the shaft diameter and bearing clearance. The formula for preload
calculation is:
| Preload = 1 - |
(Bearing Dia. - Shaft Dia.) |
| ___________ |
| (Shoe Dia. - Shaft Dia.) |
Preload in other words is the load generated from the axial interference
within a bearing resulting in elastic deformation between rolling elements
and the raceway. It is the axial load applied permanently to bearings to
ensure proper operation under external load.
Rigid preload involves a gap between the faces of opposite
bearings that is eliminated when bearings are locked axially. It may change
due to thermal expansion.
Elastic preload, expansion is compensated for by the
springs. Bearing preload variation is minimal in this case. Bearing preload
influences speed limits, rigidity and other applicable workloads.
