Dynamic modelling of deep groove ball bearings with different local defects considering skidding and thermal elastohydrodynamic lubrication

The vibration characteristics and skidding behaviour of deep groove ball bearings (DGBBs) are significantly influenced by the evolution of local defects and thermal effects. In previous studies, the influences of skidding and thermal effects were not considered in order to simplify the model of defective bearings. But the presence of skidding and thermal should not be ignored to accurately simulate the operation of bearing. To gain a comprehensive understanding of the operational mechanism of defective bearings, it is crucial to examine the skidding and thermal characteristics of various defect types using dynamic modelling approaches. In this study, the DGBB dynamic model for seven types of defects is established, which considers the self-rotation, rotation, and radial motion of ball, the contact force, ball/cage and ball/raceway skidding, and the effects of thermal elastohydrodynamic lubrication (TEHL). Experimental data from a machine fault simulator test rig is utilized to validate the accuracy of the proposed modelling methods. The results indicate that compound defects (CDs) result in higher vibration amplitudes and more severe skidding phenomena compared to single defects (SDs). Furthermore, compound defects exhibit a greater thermal effect on the oil film in the contact area than SDs, significantly impacting the operational performance of the bearing.