Study on run-out of ball bearings - Relation between unroundness of race and locus of shaft in rotation

To find out the conditions of occurrence of non-repeatable run-out of ball bearings, an apparatus which enables setting the outer ring in a prescribed profile was developed, and the loci of the center of the shaft during rota tion were investigated. From the results the loci were found to be classifi ed into several patterns according to the combinations of the profile of th e race and number of the balls. The experimental results were confirmed by a simple numerical simulation an d the calculated results coincided with most of the experimental results ex cept in unstable conditions, and it was verified that non-repeatable run-ou t can appear in most of the conditions.