Stiffness analysis of angular contact ball bearing under non-uniform preload

Reasonable bearing preload can sufficiently ensure the good performance of bearing. Traditionally, rigid and constant preloads are used to apply uniform forces on the bearing. However, considering the machining errors, assembly errors and load conditions, the uniform preload actually manifests as a non-uniform load distribution in ball bearing. The work presents a method to analyze the bearing characters under the different preload conditions. Under non-uniform preload the bearing outer ring is rotated at a small angle with respect to inner ring. In this occasion, the stresses and deformations of rolling elements at different azimuth angles diverse from each other. As a result, the bearing stiffness is also different from that under uniform preload. In this paper, the bearing deformation and stiffness under different uniform and non-uniform preloads are analyzed using nonlinear finite element method. The results show that the relationship between axial stiffness and axial preload are nonlinear. The bearing angular stiffness increases nonlinearly with the equivalent moment under non-uniform preload.