A new numerical method for the tribo-dynamic analysis of cylindrical roller bearings

This paper proposes a new numerical method for the tribo-dynamic analysis of the CRB by coupling the roller–raceway mixed EHL model and the motion equations of the CRB multibody system. The mixed EHL model is established by an implicit solution of the empirical EHL film thickness expression and Greenwood–Tripp asperity contact formula. The CRB motion equations are derived using Lagrange multibody dynamics methodology. The proposed model improves the previous CRB dynamics models by considering the roller–raceway mixed EHL contact. Based on this model, the tribo-dynamic characteristics of CRB system and the effects of radial load, rotation speed and lubricant viscosity are analyzed. The results show that the asperity interaction accounts for 90% of the friction but a small fraction of the total contact force. The roller-inner raceway friction causes the inner ring to move horizontally, leading to a saw-like fluctuation of the contact forces within the contact zone. Moreover, a higher radial load leads to a smaller vertical motion amplitude of the inner ring. The asperity contact force shows a nonlinear decrease as the rotation speed and lubricant viscosity increase. In addition, the high rotation speed tends more to cause skidding (more than 4%). This model provides a new option for the tribo-dynamic simulations of the CRB system.