Mixed Elastohydrodynamic Lubrication in Micro Wedge-Platform Thrust Bearing Involving Adsorbed Layer

Abstract

The film pressure and film thickness distributions, carried load and friction coefficient of the hydrodynamic lubricated micro wedge-platform thrust bearing were numerically calculated when the effects of the surface roughness, the surface elastic deformation and the physically adsorbed layer on the bearing surface were incorporated. The bearing clearance is so small that the effect of the adsorbed layer is significant but in the whole lubricated area there is the continuum fluid film. The flow in the bearing is multiscale and the solution is sought from the multiscale approach. The obtained results show that for the given load, sliding speed and surface roughness, the surface elastic deformation modifies both the film pressure and film thickness distributions, it makes the total lubricating film thickness increased but reduces the maximum film pressure; For the given minimum bearing clearance and sliding speed, the increase of the surface roughness increases both the film pressure and carried load of the bearing but the surface elastic deformation reduces this surface roughness effect especially when the fluid-bearing surface interaction is strong; The surface elastic deformation, the increase of the surface roughness and the increase of the interaction strength between the fluid and the bearing surface all result in the reduction of the friction coefficient of the bearing.