Research On Traction And Braking Load Characteristics Of High-speed Emus

With the rapid development of my country’s high-speed railways,the operating speed of high-speed EMUs continues to increase.High-speed EMUs require both large traction power and superior braking devices.The traction motor exerts traction power to generate traction load,and the train starts to generate wind resistance and wheel-rail longitudinal load.The actual measurement of traction braking load has a relatively high level,but there are still difficulties in measuring the wheel-rail longitudinal creep force.This article considers that there is a certain relationship between the traction brake load,the wheel/rail longitudinal load,and the wind load.With the aid of the actual measured traction brake load,to derive the wheel/rail longitudinal creep force,which has greater economic and time significance.Reduce the difficulty of obtaining the actual test data of the circuit.The specific content of this article is as follows:(1)The dynamics model of the whole vehicle including the traction and braking system is established using dynamics software.According to the structure and suspension parameters of a certain type of domestic high-speed EMU power vehicle,a vehicle system dynamics model is established.According to the suspension mode of the motor and the structure of the braking unit,a sub-model of the traction system and a sub-model of the braking system are established.The theoretically calculated traction braking force expression and resistance characteristic parameters are assigned to the model as the traction braking parameters and resistance torque of the model.(2)The load characteristics of the vehicle system under the influence of the traction conditions and different wind speeds of the high-speed EMU are studied,and the characteristics of the longitudinal load of the EMU changing with time are obtained.The relationship between the traction power of the vehicle motor,the train speed and the load of the traction device,and the relationship between the traction power,the train speed and the longitudinal load of the wheel and rail are studied.The results show that in the constant torque traction phase of the motor,the speed has little effect on the traction load and wheel/rail longitudinal load,and it decreases linearly and slowly.Compared with the speed,the traction power has a greater effect on the two loads,and the load decreases linearly.In the constant power stage,speed and traction power have a great influence on the two loads and show a non-linear decline.In traction conditions,the wind load has a non-linear relationship with the traction rod load and the wheel/rail longitudinal load.(3)The load characteristics of the vehicle system under the influence of braking conditions and different wind speeds are studied,and the characteristics of the longitudinal load of the vehicle changing with time are obtained.Under braking conditions,the relationship between the speed of the train,air resistance and the traction rod load,as well as the relationship between the speed of the train,the wind load and the longitudinal load of the wheel and rail are studied.The results show that in the electric braking stage,as the speed decreases,the values of the traction rod load and wheel/rail longitudinal load are increasing,and the traction rod load has a greater tendency to increase.In the air braking phase,the traction rod load increases,and the wheel/rail longitudinal load changes.Small and gradually stabilized.By studying the relationship between wind load and traction load and wheel/rail longitudinal load under the influence of different wind speeds,the wheel/rail longitudinal load can be derived from the traction load.In the electric braking constant torque stage,the wind load is respectively the traction rod load and wheel/rail longitudinal load.In the constant power and air braking stage,the relational expression is nonlinear.66 figures,33 tables,54 reference.