Research On The Key Parameters Matching Of Self-Steering Bogie For Railway Freight Car

Currently the subject of railway freight in our country is to further promote the efficient, heavy-loaded, rapid, low-carbon and low-cost transportation mode. Self-steering bogie has the advantages over conventional bogies in reducing wheel rail forces and wears as well as controlling the noise in relatively low level, since its wheelsets are much easier to occupy the radial position in curved tracks, and completely meet the development requirements of green, environmental protection and energy conservation, thus it is one of the most potential running gears.According to the creep force guiding mechanism, the main technical measures, including low axle-box longitudinal stiffness and wheelsets with high tread conicity, should be used for self-steering bogies in order to improve curve performance remarkablely, and an inter-axle shear system is mounted to ensure high hunting stability. Focus on the ideal working mechanism of the inter-axle shear system, and the matching rules of the key parameters of the bogie, the following researches have been done:(1) Firstly, conduct theoretical analysis of self-steering bogie separately in straight and curved lines based on the stiffness equivalent theory of rail bogies, then analysis the influence mechanism to both the hunting stability and curving ability by placing different combinations of main parameters including bending stiffness, shearing stiffness and wheelset gravity stiffness, and give priority to discuss the fundamental role the inter-axle shear system play when self-steering bogie running on straight and curved lines, especially to point out the possible matching relation between the parameters, which means the inter-axle shear system have non-interference to self-steering ability of the wheelsets;(2) Based on the theoretical analysis of steady curve negotiating, the matching relation between axle-box longitudinal stiffness and wheelset gravity stiffness is derived aiming at the best curving ability, and then by using multi-body dynamics numerical simulation technology and comparing between simulation results and theoretical analysis results, it is verified that the ideal working status that the inter-axle shear system is in free state can be achieved, in this case, the self-steering capability of wheelsets work fully and properly, helping the bogie realize the best curving, and further explore key parameters and optimizing-matching mechanism of self-steering bogie, which should be pay attention to when it is designed;(3) Considering engineering practice is hampered by relevant constraints, the key param-eters of self-steering bogie may not reach the ideal matching state, and the inter-axle shear system will affect the curving ability. In view of this, research on the trend and laws of the wheelsets motion position, the load in the inter-axle shear system, creep force, and rail wheel wear under the combinations of the different parameter values of axle-box longitudinal stiffness and shear stiffness of inter-axle shear system when curve negotiating, furthermore, propose specific design recommendations on the key parameters in engineering practice after comprehensive analysis. At the same time, for the bogie with 25t axle-load, maximum operating speed of 120 km/h, the recommendations on the values of axle-box longitudinal stiffness and the shear stiffness of inter-axle shear system have been put forward and conduct the dynamic simulation on the vehicle with such bogies as well as the advisable key parameters, and finally evaluate all indicators according to the criterion GB/T5599-1985.