Dynamic Behaviors of Rolling Element-Raceway Tribopairs under Transient Elastohydrodynamic Lubrication

The transient elastohydrodynamic lubrication (EHL) model of point contacts between the rolling element and raceways was developed. The variations of film pressure and thickness under free vibrations of the contact solid were numerically solved based on the FFT method and semi-system approach. Simultaneously, the free vibration model of damping systems was combined and the method for predicting the dynamic behaviors of point contact tribopairs was presented. The variations of equivalent stiffness and damping coefficients were analyzed under wider load and speed ranges. The results demonstrate that the transient film thickness calculated in the EHL model using the dimensionless natural frequency which was determined by the working load and speed was more close to the experimental values. The film pressure and thickness fluctuated in the vicinity of the equilibrium position and the amplitude of the contact solid decayed because of the effects of the lubrication film. The stiffness increased with the increasing load and decreased with speed. However, the changes of the damping were complex, which were different in various load and speed ranges.