Research On Traction Transmission System Vibration And Wheel-rail Creep Characteristics Of High Speed EMU

In recent years,China’s high-speed railway has developed rapidly,and its total mileage ranks first in the world.However,with the increase of train speed,the requirements for traction and braking force are also increasing.As a key component of high-speed EMU,the traction drive system is responsible for the power output and torque transmission of bogies,and it is one of the core components to realize the traction and braking of trains.It has obvious influence on the running quality and safety of high-speed EMU.Therefore,it is of great engineering significance to study the dynamic characteristics of the main components of the traction drive system such as motor,gear box and wheels.The specific research work of this paper is as follows:(1)Taking a certain domestic high-speed EMU as the research object,based on the dynamic structural parameters of the actual vehicle system,using the multi-body dynamics software Simpack,and adopting the substructure modeling method,the dynamic model of high-speed EMU consisting of one move,one tow and two vehicles is established from bottom to top.The complete traction transmission system is considered in the model,and the measured excitation of Wuhan-Guangzhou irregular track spectrum is added.On this basis,according to the mathematical model of traction,running resistance and braking force calculation of EMU,the traction,idling and braking of the train are realized in turn by using the established train dynamics model.(2)The vibration of motor and gear box under traction,idling and braking conditions is studied,and the characteristics of vibration acceleration of motor and gear box are compared and analyzed from time domain and frequency domain.The results show that under traction and braking conditions,the vibration of the motor and gearbox is stronger than that under idling conditions because the motor continuously outputs torque and the gear transmission system continuously transmits traction torque and braking torque.Under traction and braking conditions,the vibration frequencies of motor and gear box are distributed in low frequency and high frequency,while under idling conditions,the vibration frequencies of motor and gear box are mainly concentrated in the low frequency region.(3)The dynamic meshing characteristics of gear pair under traction,idling and braking conditions are studied,including gear meshing stiffness and gear meshing load.The alternating change of the number of teeth makes the meshing stiffness of the gear also time-varying,and the meshing load of the gear can be divided into circumferential force,axial force and radial force according to the different acting directions.Among them,because the fluctuation of the circumferential force in gear meshing is the most obvious,and the direction of the circumferential force is actually the same as the vertical vibration acceleration of the gear box,it also intensifies the vertical vibration intensity of the gear box.(4)Combined with the calculation method of traction power and the generating principle of traction load,the variation characteristics of traction power and traction load during train traction are studied,and the internal relationship between them is explored.The results show that,under traction condition,the traction rod of motor car is in tension and the traction rod of trailer is in compression.In the stage of constant torque traction,the traction power suddenly increases,so does the traction load.In the constant power traction stage,the traction power remains constant and the traction load gradually decreases.(5)Using FASTSIM wheel-rail contact program algorithm,the wheel-rail creep performance of motor cars and trailers under three working conditions,such as traction,idling and braking,is studied,including the size of wheel-rail contact spot,wheel-rail creep rate and the time history of wheel-rail creep force in each working condition.The analysis results show that the contact spot areas of motor car and trailer wheels are about90 mm2 and 85 mm2,respectively.The longitudinal creep forces of the left and right wheels of the wheelset are similar in magnitude and direction,while the transverse creep forces of the left and right wheels of the wheelset are similar in magnitude and opposite in direction.Under the influence of traction devices such as motors and gearboxes,the change characteristics of creep rate and creep force of moving wheels and rails are more complex and diverse than those of trailers.There are 69 pictures,16 tables and 76 references.