Axle box bearings are the crucial components of high-speed trains (HSTs). Failure of which will directly threaten the safety of train operations. In order to describe the dynamic behavior of the axle box bearing more realistically, a dynamic model of cylindrical roller bearing is presented in this paper by considering the coupling effects of local defects and wheel-rail disturbances based on an existed model. It concludes 2 degrees of freedom for the outer raceway and 3 ones both for the inner raceway and each roller in this model. The Hertzian contact force and lubrication traction between the raceway and the roller are taken into account, as well as the gravity of the car body and the wheel-rail contact force. The local defects are described as the time-varying deflection excitations applied to the outer raceway, inner raceway and rollers respectively. By transforming the power spectrum of track irregularity into time-domain, the random excitation is input as external excitation. The fourth-order Runge-Kutta method is used to solve the equations of motion, and the dynamical behaviours of the bearing with different defects are analyzed. The results show that the outer raceway and inner raceway failure are coupled strongly with the track irregularity, whereas such coupling effect for roller failure is relatively small.

Axle box bearings,Dynamic model,Local defects,Track irregularity,Coupling characteristics