Angular misalignment between the shaft and housing occurs when the shaft deflects (bends) under the operating load. Misalignment can also occur when the bearings are too far apart.
Rigid bearings, i.e. deep groove ball bearings and cylindrical roller bearings, can accommodate only a few minutes of angular misalignment without damaging the bearing. Self-aligning bearings, e.g. self-aligning ball bearings, spherical roller bearings, toroidal roller bearings and spherical roller thrust bearings (fig. 1), can accommodate shaft deflections as well as initial misalignment resulting from machining or mounting errors. Values for the permissible misalignment are listed in the relevant product section. If the expected misalignment exceeds the permissible values, contact the SKF application engineering service.
Thrust ball bearings with sphered housing and seat washers, Y-bearing units and alignment needle roller bearings (fig. 2) can compensate for initial misalignment arising from machining or mounting errors.