Influences of external moment on the contact characteristics of angular contact ball bearings under combined loads

Angular contact ball bearings are widely used in rotating machinery. The external moment about the bearing lateral direction (i.e. the lateral moment) applied to a bearing affects the service life and performance of the bearings by influencing its internal contact characteristics. This work established a quasi-dynamic model of the ball bearing by comprehensively considering the inclination angle of the inner ring due to external lateral moment, the viscous drag, the inertial force and moment of the ball, the spin and sliding of the ball in the contact ellipse. On this basis, the operation process of angular contact ball bearings was simulated under combined radial and moment loads. The effectiveness of the model was verified experimentally, and the influences of external moments about different directions on the contact angle, slip-roll ratio, and load distribution under combined loads were analyzed. The results show that the increase in moment intensifies the spin-sliding of the rolling element. When the lateral moment and the radial load are applied together, the lateral moment can reduce the maximum load of the rolling element and causes the maximum load of the rolling element to deviate from its original position. When the lateral moment is combined with the axial and radial loads, the bearing load zone is concentrated by the rolling elements near the lateral direction. The curve of the load distribution changes from an ideal oval to a distorted oval. The research results can be used to guide the design, service life calculation, and performance evaluation of rolling bearings.