Research On Rational Matching Of The Wheel Tread Parameters And The Suspension Parameters Of EMU

There are differences in the equivalent conicity and suspension parameters of the CRH3and CRH2which are used currently and domestically, resulting in the differences of the dynamic performance. The wheel tread of CRH2has a small conicity and primary positioning stiffness. It performances well at straightline operation, but it is weak in curve passing, and parts of the tread peel seriously after long-time operation. The wheel tread of CRH3has a large conicity and primary positioning stiffness. It performances well at curve passing, but it is prone to shake in some speed section and its stability and horizontal comfort are poorer than the CRH2when running on straight line. In order to speed up the pace of CRH towards world, domestic standard EMU is currently being developed, which is planned to unify these two conicity and positioning parameters and form the tread and positioning parameters of Chinese standard EMU.Therefore, the dynamic model of CRH2is established in the SIMPACK, with an elastic wheelset and a primary steel spring model to improve the accuracy and authenticity of the simulation results. Based on the established model, the curve passing ability of CRH2on different curve radius is calculated and verificated, thereby revealing the problems that exist with the CRH2as well as the cause of these problems. Further, a method of altering the conicity of the thread and finding its suitable suspension parameters is proposed in order to achieve a new vehicle with better curve passing ability than the CRH2. The main conclusions are drawn as follows.(1) The vibration of primary steel spring of high speed EMU has some influence on the lateral and vertical vibration of the bogie frame. Therefore, the modeling of the spring in the simulation calculation of the vibration of the bogie frame of high speed EMU should be considered.(2)When passing curve, the dynamic indices of the CRH2under the deficient superelevation are better or as good as those under the balanced superelevation,except that the wheel rail vertical force is little bigger than that under the balanced superelevation. Therefore, it is preferable that actual railways be designed with suitable deficient superelevation.(3) For the CRH2with new wheel tread, the primary longitudinal stiffness and the anti-yaw damping coefficient have strong impact on dynamic indices and there is a strong interaction between the two parameters. Therefore, the influence of the interaction should be considered during optimization. The primary vertical damping coefficient strongly affects the load reduction rate, while it has little effect on the other dynamic indices.(4) A set of suspension parameters matching with the equivalent conicity0.11is obtained. The stability and curve passing ability of the optimized vehicle is better than those of the CRH2. When passing curve, the wear number goes down, and the wheel rail contact condition has been significantly improved compared to the CRH2. When running on straight line, the performance of the optimized vehicle is basically the same as the CRH2.