Song Rong-rong

Influence of the orientation stiffness of tumbler journal box to the stability of high speed vehicles

The structure of tumbler journal box orientation mode was widely used in the high speed EMU, as it has the excellence of the stiffness in longitudinal, lateral and vertical direction can be set respectively. The longitudinal stiffness and lateral stiffness of the journal box was supplied by the stiffness of the elasticity node of tumbler. The stability of the high speed vehicle has a big relation with the stiffness of the elasticity node of tumbler. The dynamic model of the high speed vehicle was set up based on the analysis of the structure of the tumbler journal box in detail. The linear and nonlinear stability analysis of the model in which the parameter of the real vehicle was used was carried out first, the influence of the variable of the longitudinal stiffness and the lateral stiffness of the elasticity node of tumbler to the hunting stability of the high speed vehicle was researched. The stiffness of the elasticity node of tumbler especially the longitudinal stiffness has a big influence to the hunting speed of the high speed vehicle.

Influence of the journal box positioning method to the load of tumbler node

The damage of the tumbler node was one of the common phenomena of the damage of the tumbler journal box setting. Aimed to the easy damage problem of the tumbler node of the CW-2 style bogie, two positioning method of the tumbler journal box was compared, one is the tumbler journal box of the CW-2 bogie, the other is the tumbler journal box on the high speed motor car of CRH2. The position of the journal box spring has a big influence to the load of the tumbler node. The dynamic model of the high speed vehicles with the two different tumbler journal boxes were set up through the dynamic simulation soft SIMPACK. The simulation cases of high speed on straight line, brake condition and the condition of the horizon wind were carried to research load of the tumbler node. All the results of the three different cases were coincided with the theory analysis result. The tumbler node of the model which the CRH2 tumbler journal box was adopted has a big longitudinal and lateral force; the tumbler node of the model which the CW-2 tumbler journal box was adopted not only has a big longitudinal and lateral force, but also has a bigger vertical force. The simulation results shown that the tumbler node of the CW-2 bogie has a bigger and complex force in total, this is the just reason why the tumbler node more easy damaged than other tumbler journal box.

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 splling 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.