Partial EHL analysis of rib-roller end contact in tapered roller bearings

A partial EHL analysis was performed for the tapered rib/spherical roller end contact in tapered roller bearings. The average Reynolds equation, the elasticity equation and the pressure-viscosity relation were solved simultaneously. The effects of the surface roughness as well as the peculiar geometrical and kinematics parameters of the rib-roller end contact on the friction torque and film thickness were investigated. The optimal ratios of radius of curvature of roller end to rib face were deduced, which confirm the previous finding with the theory of smooth surfaces. The significant range of surface roughness, and the optimal surface roughness for the roller big end were obtained. It was found that asperity contacts extend into the outlet zone. The results are significant for the design of rib faces and roller ends. The theoretical treatment is validated by its good correlation with the existing experimental data for smooth surface contact.