Angular misalignments between the shaft and housing occur, for example, when the shaft bends (flexes) under the operating load, when the bearing seats in the housing are not machined to the same height or when shafts are supported by bearings in separate housings that are too far apart.
Rigid bearings, i.e. deep groove ball bearings and cylindrical roller bearings cannot accommodate any misalignment, or can only accommodate very minor misalignments, unless by force. Self-aligning bearings, i.e. self-aligning ball bearings, spherical roller bearings, toroidal roller bearings and spherical roller thrust bearings (fig 1), on the other hand, can accommodate misalignment produced under operating loads and can also compensate for initial misalignment resulting from machining or mounting errors. Values for the permissible misalignments are provided in the introductory text of the table section. If the expected misalignment exceeds the permissible values, please contact the SKF application engineering service.
Thrust ball bearings with sphered housing washers and seat rings, Y-bearing units and alignment needle roller bearings (fig 2) can compensate for initial misalignment arising from machining or mounting errors.