Line contact thermal elastohydrodynamic lubrication subjected to longitudinal vibration

Abstract

Complete numerical analysis was carried out for the time-dependent, thermal elastohydrodynamic lubrication (EHL) of line contacts. It was assumed that the contact was composed of an infinite plane and an infinitely long roller. The surfaces were running in opposite directions so that a deep dimple was produced by the action of the thermal viscosity wedge mechanism. The main purpose of this study was to examine the behaviour of the dimple when the roller was vibrating parallel to the surface of the infinite plane. The time-dependent numerical solutions were achieved instant after instant in a moving coordinate system. The lubricant was generally assumed to be a Ree-Eyring fluid, but solutions for a Newtonian fluid were also obtained for the purpose of comparison. The periodic error was checked at each end of the vibration period until the responses of pressure, film thickness and temperature were all periodic functions with the frequency of the roller's vibration. At each instant, the pressure field was solved with a multi-grid method, the surface deformation was solved with a multilevel multi-integration technique, and the temperature field was solved with a finite difference scheme through a double-direction sweeping process. The results show that, in the contact of a glass disc and a steel roller, the longitudinal vibration of the roller can produce an inlet dimple in each period, and, this dimple can then move towards the centre of the contact and become merged with the thermal dimple there.