Thermoelastohydrodynamic Lubrication Analysis of Bearing Considering Shaft Deformation and Surface Roughness

Abstract

The thermoelastrohydrodynamic lubrication properties of bearing with journal misalignment caused by shaft deformation under load considering surface morphology, thermal effect and bearing surface deformation are studied. The effect of thermal deformation of bearing surface on the thermoelastrohydrodynamic lubrication of misaligned bearing with surface roughness is discussed mainly. The lubrication of bearing is analyzed by using average flow model based generalized Reynolds equation. The deformation of bearing surface under pressure or heat of oil film is calculated by deformation matrix method. The temperature distributions of oil and bearing are calculated by energy equation and heat conduction equation. The results show that there is relatively great effect of radial clearance on the maximum film pressure, minimum film thickness, distribution of film pressure and thickness when thermal deformation of bearing surface is considered. The larger the load of bearing is, the more remarkable the effect of thermal deformation on the bearing performance will be. The rotational speed has direct relationship with the affecting degree of thermal deformation on the bearing performance. The higher the speed is, the greater the effect of thermal deformation will be. Compared with elastic deformation, the thermal deformation has greater effect on the bearing performance. The surface morphology has certain effect on the bearing performance when only thermal deformation is considered, but the effect becomes very small when thermal deformation and elastic deformation are considered simultaneously.