| | | Radial location of bearings The inner and outer rings of spherical plain bearings must be radially secured (located) to the shaft and in the housing so that the sliding movements take place, as intended, in the bearing. Otherwise the rings may begin to creep or wander in or on their seatings in the circumferential direction under load. Successful radial location is only usually achieved by using fits with sufficient interference. However, an interference fit cannot always be applied, e.g. if easy mounting and dismounting are desired, or if the bearing must be able to be displaced axially without restraint. The appropriate fits are always determined by the operating conditions. | | |
| | | 1. Type and magnitude of the load The degree of interference must suit the type and magnitude of the load, i.e. the heavier the load, and the higher the shock content, the heavier the interference required fig |7 ). • Under heavy loads, spherical plain bearings will deform elastically which may lead to a loosening of the fit and creeping of the ring on/in its seating. • The strength of the associated components must be adequate to industrial take up the loads and fully support the bearing. • If the associated components deform, there is a risk that hardened bearing rings will break. • Steel-on-steel spherical plain bearings require tighter fits than the maintenance-free bearings which have lower friction. | | 2. Bearing internal clearance An interference fit will cause the • inner ring to expand elastically, and the • outer ring to be compressed elastic-ally. This reduces the original internal clearance in the bearing to the so-called operating clearance fig ^ ). The clearance also depends on load and temperature. The original internal clearance differs depending on the type and size of the bearing and has been selected so that if the recommended tolerances for the shaft and housing seatings are applied, an appropriate operational clearance (or preload) will be left in the bearing under normal operating conditions. If interference fits are used for both bearing rings, or if the temperature conditions are unusual, it may be necessary to use a larger initial internal clearance than "Normal" for steel-on-steel bearings. | | |