Out-of-Round Wheels and the Correlation Problem of Metro Vehicles

Spalling like scales of fish will emerge on the connection area between wheel tread and flange of one metro vehicle after it running a period of time on the track. The method of polish the track has not solved the phenomena yet. When wheel is out-of-round, the vertical vibration of the car-body is very big, and the tread must be cut to eliminate the phenomena of vertical vibration big of the car-body, but this method could not solve the problem indeed. These phenomena show that the secondary suspension of the vehicles has not damp function. Both the results of linear frequency analyses and the nonlinear analyses show that the too big stiffness of the traction bar which connected the car-body and the bogie in longitudinal direction has big relation with the vertical dynamic performance of the metro vehicle. From the point of view of the wheel-set longitudinal vibration find that the wheel-set resonance speed is in the usually running speed scope of the metro vehicle and this may be the reason of wheel tread easy spiling and out-of-round. The stiffness of the traction bar was depressed by change the two ends to big rubber joints, so the longitudinal force affected by the traction bar is depressed notability, and the vertical dynamic performance of the metro vehicles is then be improved.