On the Influence of Traction Coefficient on the Cage Angular Velocity in Roller Bearings

Abstract

The influence of different traction models on the dynamic performance of a radially loaded cylindrical roller bearing is investigated by means of a dynamic model of the bearing assembly. Two simplified traction curves along with two viscoelastic rheological models are employed to estimate the traction coefficient of MIL-L-7808-type lubricant between the roller and the races. The cage rotational speed as a function of traction forces between the roller and the races is calculated for a wide range of rotational speeds and bearing loads. Comparison of the simulation results to those of published experimental measurements reveals that the dynamic model with an appropriate viscoelastic rheological model is capable of realistically predicting the dynamic response of rolling elements under various operating conditions. However, in the case of low sliding velocities, employing a simplified traction curve may lead to acceptable results. The dynamic model was further extended to study the cage wear rate, and the results indicate that high rotational speeds and low radial loads can increase the cage wear rate due to high sliding velocities between the rollers and the races.