Thermal Elastohydrodynamic Lubrication of Rolling/Sliding Line Contacts

Abstract

The solution of thermal elastohydrodynamic lubrication of rolling/sliding line contacts has been obtained. The Newton-Raphson technique was used to solve the simultaneous system of Reynolds and elasticity equations. The energy equation with boundary conditions was solved by the finite-difference method. Two models were developed: one with a constant viscosity across the oil film and another with a variable viscosity across the oil film. Different viscosity formulas such as modified WLF, Roelands, and Barus can be used in these models. Viscosity measurements were also performed over wide ranges of pressure and temperature. A very good fitting of experimentally measured viscosity by modified WLF formula was obtained. The oil film shape and minimum film thickness were calculated for pure rolling and high slip. For high slip and high rolling velocity, a tapered wedge shape of EHL film (in the longitudinal direction) was obtained. These results show a good correlation with measurements reported in other papers. They show that there is a significant influence of temperature on the oil film shape.