Theoretical Study of the Parameters Affecting Vane Tip Friction in Oil Vane Pumps Using Simplified Tehl-Model

Abstract

A simple (Thermo-Elasto-Hydrodynamic Lubrication) TEHL-Model was developed to calculate the friction forces between vane tip and cam-ring in oil vane pumps. The incentive of this work is to present an effective and sim-ple tool that helps vane pump designers to make a primary study of the effect of important parameters on the friction coefficient between vane tip and cam-ring. Such parameters are relative vane tip speed, normal vane force and vane tip radius of curvature. Navier- Stokes and energy equations were numerically solved using a finite difference tech-nique. The viscosity and density distributions as a function of pressure and temperature were taken into consideration. The results show that the effect of the normal vane force is very small compared to the relative speed. The vane tip relative speed should be higher than 4.8 m/s for reduced vane tip friction. Increasing of van tip radius of curvature and relative speed as well as decreasing of normal vane force, increases the lubricant oil film thickness and decreases the vane tip friction coefficient. It is feasible to concentrate future studies to include the effect of the material surface properties into TEHL-Model.