Influence of a ring flat zone in the point contact surface on thermal elastohydrodynamic lubrication

Abstract

This paper describes a geometrical profile, an elastohydrodynamically lubricated point contact surface with a ring flat zone, aimed at building up local line contact elastohydrodynamic lubrication (EHL) in point contact conjunctions to reduce the influence of side-leakage on the central film thickness. Effects of the ring flat zone on the thermal EHL characteristics are studied. A dimensionless coefficient, r W, is defined to represent the relative half width of the ring flat zone in a point contact EHL surface. Thermal EHL numerical simulations have been performed to investigate the influence of r W on the film thickness as well as pressure, temperature and friction coefficients under different operating conditions. In the range of 0≤ r W≤1.0 results show that the minimum film thickness decreases with increasing r W and the central film thickness increases with increasing r W, and the influence of r W on the film thickness is more pronounced than those on the maximum pressure, the maximum temperature and the friction coefficients. It is revealed that the proposed ring flat zone with appropriate width is beneficial to the thermal lubrication.