The influence of race waviness on skidding characteristics of rolling bearings

Waviness is the main shape deviation generated in the processing of rolling bearings. The existence of race waviness directly alters displacement excitation and contact stiffness between the ball and the wavy race simultaneously, which will greatly affect the dynamic performance of rolling bearings. Most of the current work studying bearing dynamics with race waviness ignored the influence of waviness on contact stiffness. In addition, the influence of race waviness on bearing skidding problems was rarely investigated. To fill the research gap, a skidding dynamic model of race waviness bearing coupled with the time-varying displacement excitation and time-varying contact stiffness excitation is established by considering the nonlinear factors including internal nonlinear contact, non-continuous collision contact between ball and cage, lubrication friction, clearance and pocket gap. The validity of the dynamic model is verified by previously published results and analytical results of a static model. The influence of waviness amplitude and order on the contact and skidding characteristics are analyzed. The results indicate that the contact stiffness and contact force between the ball and race increase with the waviness amplitude and order. In addition, the waviness also causes fluctuations in the contact force. The increase in waviness amplitude and order restrains the skidding of the ball in the unloaded area. The waviness amplitude causes significant fluctuations in skidding, and the waviness order increases the number of skidding fluctuations. The results provide a theoretical basis for the surface quality assessment of rolling bearings via dynamic studies.