Evaluation of PV Limits for Plastic Bearing Materials

Abstract

Polymeric bearing materials are usually operated below a limit of sliding severity expressed as the PV limit, where P is the average contact pressure and V is the surface sliding speed. In principle the PV limit should relate to the occurrence of melting on the polymer surface but cannot be derived from the physical properties of the polymer. The thermal properties of the counterface material and the manner of formation of transfer film appear to be as important in controlling the rate of wear as the softening temperature of the polymer. The influence of surface finish is not yet clear.