Nonlinear dynamic analysis of cylindrical roller bearing with flexible rings

Abstract

A nonlinear plan dynamic model for cylindrical bearings has been developed, predicting the interaction forces between the retainers and the rolling elements. Roller–race contacts are analyzed in detail and resulting forces and moments are determined. An elastohydrodynamic lubrication (EHL) model provides the traction components while a hydrodynamic formulation is used for the roller–cage interactions. Structural deformations of the rings are included in the geometrical equations linking the relative displacements between rings. The Newmark type implicit integration technique coupled with the Newton–Raphson method is used to solve the differential equation system iteratively. Time displacements and theirs FFT are used to illustrate and elucidate the diversity of the system response. Computations performed when considering the structural deformations of the rings show a low frequency shift, as higher harmonics are attenuated while the first are more pronounced. With an unbalanced rotor, the ball pass frequency (BPF) is modulated with this perturbation leading to an aperiodic response. This is particularly true for the counter-rotating bearing investigated. Finally, results for different cage materials show a significant influence only on the cage center location, whereas the inertia moment of the cage is of little impact on the global dynamics behavior.