Study On Asymmetrical Hunting Phenomenon Of Lending And Trailing Bogies For Co-Co Axle-Mounted Locomotives

In engineering calculation of vehicle dynamics for Co-Co axle-mounted locomotives a kind of asymmetrical phenomenon for leading and trailing bogies is found that under a certain speed leading bogie is unstable while trailing bogie is stable. To investigate the phenomenon, a mathematical model of elastic positioning of wheelset driving system with two degrees on lateral dynamics is established, and numerical analysis and analytical analysis are used to analyze this model. Result shows that stability of mass center of wheelset driving system in the front is better than that in the back. In this paper, a certain type of internal Co-Co axle-mounted locomotive is for the study. Do research on the stability of leading and trailing bogies and the influences on the structure parameters.The simulation results show that:1) the bigger equivalent conicity, the worse the stability of bogies and the smaller difference between critical speeds of bogies.2) The wider the track gauge, the worse the stability of leading and trailing bogies and the bigger difference between critical speeds of bogies.3) The greater the mass of wheelset, the worse the stability of bogies and the smaller difference between critical speeds of bogies. The greater the mass of motor, the worse the stability of bogies and the bigger difference between critical speeds of bogies.4) The greater the inertia moment of wheelset, the worse the stability of bogies and the smaller difference between critical speeds of bogies. The greater the inertia moment of motor, the worse the stability of bogies.5) The greater the stiffness of primary suspension, the better the stability of bogies and the bigger difference between critical speeds of bogies.6) The bigger the positioning space of primary suspension, the better the stability of bogies and the bigger difference between critical speeds of bogies.7) The bigger the radius of wheelset, the better the stability of bogies and the bigger difference between critical speeds of bogies.Finally, the paper compares the influences of the structural parameters on bogies with that on the mathematical model of wheelset driving system, finds that the rules of two models are the same. Therefore, asymmetrical phenomenon for leading and trailing bogies can be explained by the mathematical model of elastic positioning of wheelset driving system, and also the mathematical model of elastic positioning of wheelset driving system can be verified by the whole locomotive model.