Slipping characteristics of rolling element bearing considering local defects and cage flexibility

Abstract Slipping and local defects are significant causes of abnormal vibration and instability in rolling element bearings (REBs). In particular, the secondary slipping of rolling elements (REs) triggered by local defects on the raceway would exacerbate the vibration and reduce rotational precision of the bearing system. Therefore, to more accurately reveal the characteristics of local slipping and the vibration response mechanisms in defective bearings, a comprehensive 4 N b + 4 degrees of freedom dynamic model of defective REB with flexible cage is proposed. This model based on the consideration of time-varying displacement excitation, cage stiffness and damping, pocket clearance, and isothermal elastohydrodynamic lubrication. Through comparisons the simulation results with both experimental and reference results, the proposed model is verified. The study investigated variations in contact forces between REs and overall raceways in detail, especially the trend of changes within the local defect area as the defect width increases. Furthermore, the effects of flexible cage stiffness, radial load, and speed on bearing slipping behavior are explored, along with the secondary slipping phenomenon triggered by local raceway defects. The results indicate that with increase of flexible cage stiffness and load, the REs slipping speed and cage slipping rate would decrease. Conversely, as rotational speed increases, both slipping speed and cage slipping rate would also increase.