A study on the effect of acceleration on slip velocity and lubrication performance in cylindrical roller bearings

Abstract

Skidding may cause wear and incipient failure of rollers and races of cylindrical roller bearings when the roller is loaded. The previous skidding studies on bearings are mainly focused on steady state condition. However, bearings often operate under different accelerations. This paper proposes an analytical model to investigate skidding between the maximum loaded roller and the races taking account of contact force and friction force between the roller, the cage and the races, fluid pressure and centrifugal force of roller. This model consists of nonlinear first-order ordinary differential equations which can be solved using Euler method. The results of this model are compared to the results of Harris model (steady-state condition) to analyze the effect of acceleration on skidding. A mixed elastohydrodynamic lubrication model which is capable of handling practical case with 3D machined roughness is used to study the lubricating performance between the maximum loaded roller and the inner race during acceleration. The results indicate that acceleration has a great impact on hydrodynamic pressure, friction coefficient, and contact stress, however, the acceleration can hardly affect oil film thickness and contact area ratio.