Methods of location
Bearings with a cylindrical boreBearing rings having an interference fit are generally mounted so that the ring abuts a shoulder on the shaft or in the housing on one side (fig 1). On the opposite side, inner rings are normally secured using lock nuts, as shown in the section Lock nuts, e.g. of type KM + MB (fig 2) or by end plates (fig 3) attached to the shaft end. Outer rings are usually retained by the housing end cover (fig 4) or possibly, in special cases, by a threaded ring (fig 5).
Instead of integral shaft or housing shoulders, it is frequently more convenient to use spacer sleeves or collars between the bearing rings or between a bearing ring and an adjacent component, e.g. a gear (fig 6). Location on a shaft can also be accomplished using a split collar that is seated in a groove in the shaft and retained either by a second one-piece collar or ring or by the bearing inner ring.
The use of snap rings for the axial location of rolling bearings saves space, permits rapid mounting and dismounting, and simplifies the machining of shafts and housing bores. If moderate or heavy axial loads have to be supported an abutment collar should be inserted between the bearing ring and the snap ring, so that the snap ring is not subjected to excessive bending moments (fig 7). The usual axial play between the snap ring and snap ring groove can be reduced, if necessary, by choosing suitable tolerances for the abutment collar or by using shims. Bearings with a snap ring groove in the outer ring (fig 8) can be secured in a very simple and space-saving manner using a snap ring, see section Single row deep groove ball bearings.
Other methods of axial location which are suitable, especially for high precision bearing arrangements involve the use of press fits, e.g. in the form of stepped sleeve arrangements. Additional details can be found in the SKF catalogue "Super-precision bearings"
Bearings with a tapered boreBearings with a tapered bore mounted directly on tapered journals are generally secured on the shaft by a lock nut (fig 9).
When using an adapter sleeve on a stepped shaft, the lock nut positions the bearing relative to the sleeve, and a spacer ring is inserted between the shaft shoulder and inner ring on the other side (fig 10). Where smooth shafts without integral abutments are used (fig 11), the friction between the shaft and sleeve governs the axial load carrying capacity of the bearing, see sections
- Self-aligning ball bearings and
- Spherical roller bearings.
Where bearings are mounted on a withdrawal sleeve, an abutment, e.g. a spacer ring, which is frequently designed as a labyrinth ring, must support the inner ring. The withdrawal sleeve itself is axially located by an end plate or a lock nut (fig 12).