Contact Analysis Between Rollers and Raceway of Axle Box Bearing Under Multi-source Fault

The axle box bearing is highly nonlinear and affected by external excitation factors during the service process, such as the running environment of the vehicle and wheel-rail excitations. Based on the coupling dynamics model of a high-speed train and axle box bearing, wheel tread damage and bearing outer ring fault were introduced in this paper. On this basis, the contact force between the roller and raceway of the bearing in the presence of multi-source faults was analyzed. In addition, the simulation of the vehicle running in tangent-line and curve-line conditions was carried out, and the evolution law of bearing contact force was further revealed through analysis. Through research, it is found that the curve-line running conditions have a significant impact on the bearing contact force. The following conclusions can be drawn from the analysis: If the wheel is normal, faulty bearings are more affected when running in a tangent-line, while normal bearings are more affected when running in a curve-line. The maximum difference between the tangent and curve conditions occurs in normal bearing of the longitudinal direction. If the wheel is defective, the distribution of contact force in curve-line running is close, with peak values of 251.77 kN. Meanwhile, the RMS of the fault bearing essentially stays the same in comparison to the normal bearing, so the vibration caused by a bearing fault is relatively weak when compared to the excitation caused by a wheel flat. When running in a curve, the contact force of the normal bearing in the longitudinal direction increases by a factor of about 74.69, with the largest growth range. The smaller the radius of the curve, the greater the influence of the contact force, and also the larger the fluctuation of the contact force between the roller and raceway, so that the probability of bearing fatigue damage greatly increases.