Analysis of varying contact angles and load distributions in defective angular contact ball bearing

Angular contact ball bearing (ACBB) is widely used in rotating machinery for its great external load capacity. The operating condition of ACBB is easily affected by surrounding mechanical components. The variations of contact angles and load distributions can sufficiently reflect the operating condition of ACBB. A localized defect on the raceway will lead to the dramatic change of contact angle and load distribution of ACBB. In this paper, a mechanical model of ACBB with a localized defect on outer raceway is established, in which the effects of centrifugal force and gyroscopic moment on the force equilibrium relation of balls in high speed operating condition are considered. The proposed model is verified by comparing with the existing model in literature. On the basis of the proposed bearing model, the effects of some parameters on the variations of contact angles and load distributions are investigated. The results show that as the operating speed increases, the centrifugal forces of balls increase and the balls are gradually moving towards outer raceway, which results in that the load distributions between balls and outer raceway are much larger than those between balls and inner raceway. In view of the combined external forces and moments acted on the bearing, the variations of contact angles and load distributions become more complicated than those under the single force or moment applied condition. With the increase of the circumferential extent of localized defect, abrupt changes of contact angles and load distributions in defect area increase obviously.