Two-dimensional quantitative analysis model with a shallow spall of rolling element bearing based on early weak multi-impact characteristics

The shallow spall faults will lead to multiple additional contact phenomenon of rolling element passing through the defects in the early stage of crack-to-spall evolution. The existing bearing defect analysis models ignore this stage. In this paper, the mechanism of the shallow spall fault is analyzed, and the width and depth of the spall are quantitatively studied. Based on Hertz contact theory, a multi-impact dynamic model of raceway spall damage on the rolling element bearing outer ring is constructed by time-varying contact displacement and force. The dynamic response of raceway spall damage on the rolling element bearing outer ring is calculated by the Runge–Kutta method under different spall sizes and compared with the existing dual-impact model. The results show that the model accurately describes the phenomenon of weak multi-impact in early stage of the shallow spall. The two-dimensional spall including spall width and depth are quantified in this model, compared with the limitation of the dual-impact model which only quantifies the spall width. This model fills in the blank of the mechanism model with early weak multi-impact characteristics of bearing defect evolution in the whole life. It is of great significance for rolling element bearing damage degree evaluation.