Vibration Feature of Locomotive Axle Box with a Localized Defect in its Bearing Outer Race

摘要

The axle box bearing is a critical component to support the vehicle and reduce the friction effect between the wheelset and the axle box. As one of the major failure modes, the localized defect in the outer race of the axle box bearing is a great threat to the operation safety of railway vehicles. Therefore, it is helpful to investigate the dynamic features of locomotive with effect of a localized defect of axle box bearing so as for better understanding of the bearing fault mechanism. In this paper, a locomotive-track coupled dynamics model with traction transmissions is proposed where the dynamics sub-model of the axle box rolling bearing is included. And the impact effect between the roller and the defect region is described as the time-varying displacement excitation and the time-varying contact stiffness excitation of the fault bearing. The results show that the passing frequency of roller and its harmonics of the vertical acceleration vibration of the axle box could be good indicators for the diagnosis of this localized defect, even if the fault feature could not be observed in the time history signals under the wheel-rail interaction. This work can provide some guidance for the early localized defect detection and diagnosis for the axle box bearing.