Effects of Thermal Conductivity of Contacting Surfaces on Point EHL Contacts

Abstract

With actual and virtual materials, the effects of the thermal conductivity of contacting surfaces on EHL are investigated through experimental analyses using the optical interferometry technique and the Newtonian thermal EHL analyses in consideration of the variation of oil properties in all directions within the film. A mineral bright stock is used as a lubricant. It is found that the distributions of pressure and film thickness, including the minimum film thickness, are influenced very much by the entrainment velocity and the slide-roll ratio. One of the causes is the temperature-viscosity wedge action produced by the temperature variation across the oil film, and the other is an increase in oil temperature at the entrance of the contact due to the heat produced by the compression work and the shearing of the oil. The degree of both influences depends on the thermal properties of contacting materials.