Effect of Inertia Forces on Contact State of Ball Bearing with Local Defect in Outer Raceway

Abstract Based on the de Mul bearing model, a five-degrees-of-freedom quasi-static model with local defect is proposed, after which its validity is verified. The inertial force of the ball will affect the contact state between itself and the raceway, thus affecting the mechanical properties of the bearing. Taking centrifugal force and gyro moment as analysis objects, the effect of their single action on bearing contact state is studied. The results of this study show that the centrifugal force and gyro moment of the ball will increase with an increase in bearing rotation speed. Ignoring centrifugal force, the normal load between the ball and raceways increases slightly with the increase of gyro torque, while the contact angle almost remains unchanged. Ignoring gyro moment, with the increase of centrifugal force, there is an increase in the normal load between the ball and outer raceway and a decrease in contact angle. On the other hand, the normal load between the ball and inner raceway decreases, whereas there is an increase in contact angle. In comparison to centrifugal force, gyro torque has less influence on bearing contact angle and load distribution. When a ball enters into the defect, it will be partially or completely unloaded. Thereafter, the unloaded load will be distributed to the adjacent balls, the load will be redistributed, and the mechanical properties of the bearing will be completely changed. In addition to revealing the action mechanism of centrifugal force and gyroscopic moment, this work provides a theoretical basis for the mechanical research of high-speed bearing.