Numerical simulation of defective gear transmission under mixed EHL conditions

Abstract

Pitting is a common phenomenon for gears. The mechanisms governing the lubrication and vibration caused by the peeling of the material are not well understood, which limits the development of precision and reliability of gear transmission. In this paper, a transient mixed lubrication model is proposed to study the meshing behaviors of spur gears with pit defects. For a start, the time-varying contact parameters are calculated using tooth contact analysis along the meshing path. Then, the entire meshing process of a single teeth pair is simulated using the grid moving method. The influences of different pit geometries on gear meshing are studied, and the impacts of the pit at different speeds are also investigated. Simulation results show that defects will not only increase the asperity contact ratio but also cause fluctuations in contact stiffness and normal distance. The expansion of defect dimensions greatly affects the contact stiffness and normal distance, while the expansion of defect depth has a limited effect on them when the defect has already reached a certain depth.