A new load-sharing-based approach to model mixed-lubrication contact of spur gears

Abstract

An isothermal model is developed for predicting the performance of spur gears with provision for surface roughness. For each point along the line of action of the gears, the contact of pinion and gear is replaced by that of two cylinders. The radii of cylinders and transmitted load are calculated, and lubricant film thickness as well as contribution of fluid film and asperities in carrying the total load is obtained using the Johnson’s load-sharing concept. For each asperity in contact, occurrence of elastic, plastic, and elasto-plastic deformation is investigated. To validate the analysis, the predicted film thickness and the friction coefficient are compared to published theoretical data. The results of a series of simulations presenting the effect of surface roughness, load, and speed on the friction coefficient are presented and discussed.