A new instantaneous contact based dynamic model of rolling element bearings with local defects

An accurate dynamic model is significant for the understanding of defect induced dynamic characteristics of rolling element bearings, which further contributes to effective diagnosis and prognosis of bearings. In the development of dynamic models of bearings, how to model the contacts between the defective component and normal component is of vital importance. Existing contact models use displacement excitation instead of actual roller-defective raceway contact and thus leave space for improvement. To fill in this gap, this paper proposes a new dynamic model of rolling element bearings with a defect on the inner or outer raceway in a rotating reference frame with the gyroscopic effect and gravity force considered. In the proposed model, the contact between the roller and the defective raceway is modeled based on the instant positions of the rollers, cage, inner ring and outer ring. The effectiveness of the proposed model is validated through simulation and experiment studies. The results have shown that compared with the existing models, the proposed model exhibits a more gradual load change in the stressing stage and the restressing stage when the roller passes through the defect, yielding a more accurate modeling of the real contact of bearing components.