Research On Hydraulic Radial Mechanism Of Single-Axle Bogie For Urban Rail Vehicles

With the increase of urban population and the number of cars, traffic congestion has become a worldwide problem. The development of the city rail transit with the characteristics of quick rapid, large transit quality, energy saving and environmental protection has been proved to be the most effective solution. However, compared with traditional railway traffic, the operating environment of urban rail transit has more curves and the radii are smaller, so the wheel/rail wear is especially prominent. Therefore, improving the curving performance of urban rail vehicles has been the focus of the research on urban rail transit technology.Single-axle bogie has a significant advantage in reducing vehicle weight, easing wheel-rail force, reducing operating noise and improving the curving performance, but it also has poor stability compared with the traditional two-axle truck, it is necessary to take a series of measures to improve its stability. Based on this point, a hydraulic radial mechanism which mounted between the bogie frame and body was designed for the urban rail vehicle with single-axle bogies, the mechanism can improve the stability by longitudinal positioning as well as keep the curving performance.Firstly, the paper presents the domestic and foreign situation of research and development on axle bogie technology and radial technology. An urban rail train with single-axle bogies is chosen as the study object, the dynamic differential equations of the train are derived and the dynamics model is established in the SIMPACK software.Secondly, the paper proposes the general structure scheme and the working principle of the hydraulic radial mechanism. And then the structure design of the mechanism is completed. The simulation model of the mechanism is established in the AMESim software. The SIMPACK dynamic simulation model is integrated with the AMESim hydraulic radial mechanism simulation model through the software interface in SIMULINK to compose the SIMPACK/AMESim/SIMULINK co-simulation model.By using the SIMPACK/AMESim/SIMULINK co-simulation model, kinematics simulation and dynamics simulation of the single-axle bogie vehicle with hydraulic radial mechanism are accomplished. The kinematic characteristics of the hydraulic radial mechanism are analyzed. The influences of the hydraulic radial mechanism on dynamic performance of the vehicles are studied and the parameters of the mechanism are optimized.On the basis of parameter optimization of the hydraulic radial mechanism, the stability, riding quality, and curve negotiation of the single-axle bogie vehicle with hydraulic radial mechanism are analyzed by using the SIMPACK/AMESim/SIMULINK co-simulation model again. Finally, the dynamics performance of the single-axle bogie vehicle with yaw damper is compared with that of the single-axle bogie vehicle with hydraulic radial mechanism. The results show that the hydraulic radial mechanism is the better solution to the contradiction between curving performance and hunting stability for the single-axle bogie vehicle.