Dynamic Modelling of Solid-Lubricated Ball Bearings Based on the Spinning Traction Curve of Ball

Ball bearings play a significant role in guaranteeing the stable operation of liquid rocket engines (LREs). To accurately analyze the static and dynamic characteristics of LRE bearings, full consideration of forces acting on the bearing components is needed. In this paper, a new spinning traction torque calculation approach for the ball called “the spinning traction curve” is proposed to ensure the accuracy and efficiency of the traction model. Based on the new traction model and a modified contact angle calculation method, a dynamic model of the ball bearing is developed considering six degree-of-freedoms of the ball as well as contact impacts between the ball and the cage. The proposed model is validated by comparing the results with the conventional quasi-static Jones-Harris model. The results show that the collision between the ball and the cage can significantly increase the sliding between the ball and the raceway, which is caused by the uneven load distribution originated by the radial load. An increase in the axial load can diminish this inhomogeneity of load and thus suppress the ball-cage collision.