Accuracy of seats and abutments
Geometrical and running accuracyMaximum running accuracy, high speeds and low operating temperatures can only be achieved, even with super-precision bearings, if the mating parts and other associated components are made with equal precision as the bearings. Deviations from geometric form of associated seats and abutments should therefore be kept to a minimum when machining mating parts. Form and position recommendations in accordance with ISO 1101:2012 are provided in table 1.
Thin-walled bearing rings adapt themselves to the form of their seat. Any errors of form on the shaft or housing seat can therefore affect the bearing raceways and bearing performance, e.g. angular misalignment of one bearing ring relative to the other, can cause loss of running accuracy, load concentration and high operating temperatures, particularly at high speeds. The numerical values of IT tolerance grades in accordance with ISO 286-1:2010 are listed in table 2.