A study of the film formation for a rough slider bearing

Abstract

An average Reynolds equation, suggested by Patir and Cheng, is applied to the compound random surfaces, including both roughness and waviness, in the present paper. The critical load capacity W cr , at the moment when the minimum nominal film thickness h min = CR p , is regarded as the criterion to evaluate the film formation ability of nominally flat friction pairs. The important influence on the critical load capacity of the height profile of rough surfaces is demonstrated, i.e. W cr will increase rapidly as the values of a and R p / σ reduce. The critical load capacity of various slider bearings with different surface topographies is calculated and measured. The experimental results for the different specimens are similar to those predicted by the computer simulation. The significant effect of the height profile on film formation is confirmed by experiment. The simulation indicates that the good lubrication behaviour of wide scraped surfaces mainly results from the fact that they have smaller a and R p / σ characteristics, and a larger waviness component with longer wavelength.