Analysis Of Dynamic Contact Characteristics And Contact Fatigue Mechanism Of High Speed Train Transmission Gear

For high-speed train transmission system,transmission gear is the key component to realize power transmission,and the stability of its meshing directly affects the performance of the train.With the increase of the mileage of high-speed railway,fatigue damage of transmission gear gradually appears in the long-term service process.Contact fatigue damage such as pitting and spalling is common among these fatigue failure gears.Therefore,the analysis of dynamic contact characteristics and contact fatigue damage mechanism of high-speed train transmission gear under different working conditions is of great engineering significance for reliability evaluation and maintenance of high-speed train gear.In this paper,the CRH3 C transmission gear was taken as the research object.The finite element method was used to discretization the solid model of the gear created by parameterization.Combined with the EHL time-varying friction model considering the effect of slip difference between the teeth,the transient contact finite element model of the transmission gear at low speed and high speed was constructed.The finite element model of transmission gear was verified based on Hertz contact theory.By using the implicit and explicit dynamic contact algorithms provided by the nonlinear finite element software ABAQUS,the contact dynamic characteristics of transmission gears at low and high speeds were studied respectively.At low speed,the implicit dynamic contact algorithm was directly used to simulate the dynamic contact characteristics of transmission gears under the conditions of EHL time-varying friction without friction and considering slip and different constant friction coefficients,and the effects of different friction excitation on the contact force,contact stress and state of the gear surface were obtained.Under high-speed operation condition,by using explicit will accelerate to set speed gear transmission system,to accelerate again after the state as the initial field variables,at the end of the drive gear dynamic contact characteristics of high speed working conditions was analyzed,and the contrast analysis of the time-varying friction excitation,considering the influences of slip motor harmonic excitation,the track spectrum form different role,such as incentives to drive the system output shaft speed,the influence of tooth contact force characteristics.In addition,based on the results of finite element simulation,load spectrum and material curve,the nominal stress method was used to predict the contact fatigue life of transmission gear.In addition,based on the results of finite element simulation,load spectrum and material curve,the nominal stress method was used to predict the contact fatigue life of transmission gear.By means of SEM electron microscope,nano-indentation instrument,3D surface profiler and other equipment,the microstructure and fatigue damage of fatigue samples with different slip rate were analyzed,and the causes of fatigue damage were analyzed in combination with relevant theories of materials...