Study On Tooth Modification And Transmission Efficiency Of High-speed Railway Gear Box

The gear transmission system is an important part of the mechanical transmission system,and the gearbox is an important part of the transmission system in the traction device of rail transit,which has a great impact on the locomotive power and bearing capacity.In the running process of high-speed railway,there will be many complex working conditions,such as acceleration,deceleration,emergency braking,etc.,which will have a great impact on the gearbox.As an important part of locomotive power,its transmission efficiency will directly affect the working efficiency and economic benefits of bullet train.Therefore,in order to improve the bearing capacity and transmission efficiency of traction device,it is of great practical significance to analyze its transmission efficiency.However,in the process of gear assembly and processing,due to the existence of machining and assembly errors,the uneven load distribution and impact phenomenon on the tooth surface of the gear appear in the meshing process,which will reduce the service life and bearing capacity of the gear,and increase the noise and vibration of the gear transmission system.In the actual production process,in order to improve the bearing capacity of the gears,the gears are generally modified to effectively improve the meshing performance.However,the selection of modification parameters will have an impact on the transmission error of the gears,thus affecting the meshing efficiency of the gears and ultimately the transmission efficiency.Therefore,the determination of gear modification parameters is the key to the result of modification.Therefore,the design research of gear modification parameters has important theoretical and practical significance for reducing noise and vibration and improving the transmission efficiency of gear box.In this paper,a helical gear transmission model was established by using Romax Designer.Under given working conditions,the driving wheel(pinion)was modified in microscopic geometry according to the performance indexes such as the transmission error curve,the load distribution on the tooth surface and the maximum contact stress distribution on the tooth surface.The micro-parameters of the gear pair were optimized by Monte Carlo method of Romax Designer software,and the modified parameters were obtained.Through the simulation analysis of the reducer,the unmodified shape,the parameters given by the enterprise,the manual shape modification and the micro optimization are compared,and the influence of the modification on the gear stress,transmission error and transmission efficiency is analyzed.Thus,the stress on the tooth surface is reduced,the transmission error is reduced,the transmission efficiency is improved and the vibration of the gearbox is reduced to make the transmission more stable.This paper first analyzes the tooth surface contact of the unmodified gear to determine the practice method.Secondly,according to the shape modification parameters given in the drawing,the shape modification results are further analyzed,and the next step shape modification plan is proposed.Then,through the calculation of shaping parameters,the cultivation amount and the final cultivation method were determined.The tooth profile was modified by the tooth tip trimming edge and tooth direction to the tooth end,and the shaping parameters were set in the Romax software according to the shaping parameters,and the shaping parameters were adjusted according to the contact analysis results of the tooth surface of the gear.Setting the optimization goal,and then the modification parameter is further optimum design,by optimizing the modification,the tooth to the load distribution is improved before modification,down from 1430 MPa to 557 MPa,the biggest stress transmission error reduced to 1.55 μm from 27 μm,and according to each component,the power loss in transmission efficiency analysis,through the modification of gear transmission efficiency increased by 6.3%.