Dynamic characteristics of pitted gear with variation of tooth surface topography

Abstract

As a fundamental element of a transmission system, a gear is often used in complex working conditions, wherein surface pitting ranks among prevalent gear failure modes. Previous studies on the surface pitting and dynamic characteristics of gears fail to consider the variation in surface topography induced by surface pitting, resulting in a discrepancy between the study results and actual situation. Herein, a dynamic model of a gear transmission system with surface pitting was developed by considering the involved variation in tooth surface topography to accurately predict the vibration responses of the gears. First, a distributed-pitting model was established to quantify the involved time-varying mesh stiffness (TVMS) with various pitting degrees. Then, a time-varying friction model was established to obtain the friction coefficients with the three-dimensional surface topography of the pitted tooth. Based on the pitting and friction models, a dynamic model was proposed to elucidate the dynamic characteristics and fault features of the gear transmission system with surface pitting. Results demonstrate that pitting changes the surface topography, causes variations in TVMS and friction, and further induces diverse vibration responses and characteristics. Finally, the proposed model and simulated results were validated through experimental tests.