Research On The Characterastics Of Wheelset Which Orientated Var Friction For Rolling Stock

Since 1997, china has increased the speed of railway passenger trains for six times, at present, the fastest speed of EMU which used for passenger transportation is 250km/h, china also intend to increase the speed of wagon to 160km/h, this can match the passenger and freight transportation effectually, improve the whole economic benefits of railway system. So, increase the speed of wagon has become to a very urgent task with the perfection of passenger trains in china.Because the objects of passenger vehicles and wegons are different, so there are so many big differences between them, for example, the speed, amount, safety, cost of manufacturing and maintenance, and so on, these differences are fully reflected in the design of car body and bogie. The way to orientate the wheelsets is an important difference of bogie, in order to improve the comfort and adapt the large distinction between empty and full vehicle, all of the bogie for passenger vehicles are used spring-damper which are resiliently and have a suitable primary static deflection. But most of the wagons are uses three-piece bogies, their wheelsets are orientated use friction, this bogie can adapt the big difference between empty and full vehicle because this bogie don't have primary static deflection. Many textbooks and papers have an depth study on the characteristics of wheelset which orientated by spring-damper, but only a little study are dedicate to the characteristics of wheelset which orientated by friction because the friction is complexity and strongly nonlinear, this paper mainly research on this topic.Used the theory of tribology and based on the model of static friction and friction-speed gradient, this paper summarized the relationship between friction and the relative movement speed of friction body. It also discussed the Stribeck rule of friction and the function of dry friction damper to the orientation of wheelst.An analysis model of wheelset have been established, the wheelset in it have six degrees freedom and orientated by friction. In the model, the Kalker simple method were adopted in the creep force calculation, the trace method were adopted in calculation of the wheel/rail space geometry contact relation, and the single side spring damp force element method were adopted to calculate the wheel/rail normal force. Used the model, research the dynamic characteristics of wheelset on the straight track use the theory of two-dimensional friction combined with the structure of friction orientation, then compared these characteristics with their of the wheelset which orientated by spring-damper. The results show that there are many differences between wheelset which orientated by friction and spring-damper, for example, horizontal stability, derailed coefficient, vertical vibration, horizontal vibration, wheel/rail forces and abrasion, and so on.Finally, through the variable parameters, this paper analysis the influence from parameters of friction orientation to the wheelset's dynamic characteristics, for example, the friction coefficient, horizontal gap, vertical gap between side frame and carrying-saddle, axle load, and so on. The results show that all of these parameters have obviously impaction to the dynamic characteristics of wheelset and all have an optimal range.We hope the work of this paper are contributionaly to incease the speed of china's wagon, and offer some basis to the research of railway wagon's dynamic characteristics.