The Film Formation Ability of Lubricants in Hydrodynamic Lubrication Regime

Abstract

The limiting ability of oils to build up hydrodynamic lubrication film was investigated using a plate-on cylinder testing apparatus on sliding condition. The oil viscosity entrained into the conjunction zone was estimated by comparing the values of the film thickness and coefficient of friction measured during testing and theoretical ones under oil starvation conditions. There was a critical sliding velocity above which the oil thickness and friction force inversely decreased with increasing the sliding velocity. Below the critical sliding velocity, the oil film thickness and coefficient of friction measured were nearly equal to the theoretical ones. The reduction in oil thickness and friction compared with theoretical ones of the supplied oil resulted from preferentially entraining the lower viscosity components of the supplied oil into the conjunction region.