Calculating the Contact Forces at Imperfect Surfaces Considering Elastohydrodynamic Lubrication Effects in Rolling Element Bearings

Abstract

The contact forces largely affect the vibrations of rolling element bearings with geometrical imperfections, such as pits, spalls, etc. In the current paper, a novel method to calculate the contact force of rolling element at imperfect race surfaces in rolling element bearings is proposed considering the elastohydrodynamic lubrication effect. In the proposed method, the oil film thickness, the oil film pressure and the elastic deformation are determined by solving the Reynolds equation, the oil film thickness equation, the viscosity-pressure equation, the density-pressure equation and the force balance equation simultaneously. The geometrical imperfection is considered by modifying the oil film thickness equation. The above equations are solved iteratively until satisfy the balance relationship of oil film thickness, elastic deformation and geometrical interaction. Finally, the contact force is calculated by integrating the oil film pressure in the entire contact region. Results show that the geometrical imperfection would largely affect the oil film thickness and the oil film pressure, and thus affect the contact force. The current investigation could provide a theoretical tool to calculate the contact force in dynamic models of rolling element bearings with imperfect surfaces. Meanwhile, the current method can also be used in the calculation of the contact force at textured surfaces in rolling element bearings.