Two-dimensional random surface model for asperity contact in elastohydrodynamic lubrication

Abstract

Relations for the asperity contact time fraction during elastohydrodynamic lubrication of a ball bearing are presented. The analysis is based on a two-dimensional random surface model and actual profile traces of the bearing surfaces are used as statistical sample records. The results of the analysis show that transition from 90% contact to 1% contact occurs within a dimensionless film thickness range of approximately 4–5. This thickness ratio is several times larger than that reported in the literature where onedimensional random surface models were used. It is shown that low-pass filtering of the statistical records will bring agreement between the present results and those in the literature.