Study On The Stick-slip Vibration And Noise Of The Driving Wheel End Of A Car Model Under The Launching Condition

Since the 21 st century,thanks to the rapid economic development and the rise of domestically-produced automobiles,China has become the world's largest automobile country in terms of production and sales volume and ownership.At the same time,the car's NVH(Noise,Vibration and Harshness)performance has gradually become one of the important factors that users consider when buying a car.Automobiles are highly integrated mechanical systems,including various system components with mutual friction properties,which may induce stick-slip frictional vibration noise such as clutch judder,brake flutter,and wiper abnormal noise,which seriously affects the performance of the vehicle's NVH.It may even cause excessive wear of parts and components,which poses certain safety hazards.Therefore,the study of stick-slip frictional vibration is of great significance to the improvement of automotive NVH and safety performance.Based on the theory of stick-slip friction and vibration mechanism,this paper conducts the following research work on the abnormal noise of the drive wheel end of the transmission system of a certain vehicle under the starting conditions:First of all,it is determined through experimental analysis that the abnormal ‘click' is generated at the drive wheel end,And the abnormal ‘click' is caused by stick-slip friction on the contact surface of the drive half-shaft and the hub bearing due to the excessive driving torque of the half-shaft.The drive half-shaft hub bearing system is simplified as a 1DOF rotational friction model,and three friction models of Stribeck,Karnopp,and Lugre are introduced to compare and analyze its stick-slip friction characteristics.Compared with the other two models,Karnopp has obvious advantages in simulation calculation.Then,based on the Karnopp model,the influence of system parameters such as stiffness,damping,moment of inertia,normal pressure,and friction coefficient on the characteristics of stick-slip friction is analyzed.The AMEsim simulation software was used to build a vehicle transmission model based on the relevant parameters of the test vehicle.The drive half shaft-wheel hub bearing system was simplified to the Karnopp model.The speed and friction torque on both sides of the friction model were used as observations to analyze the stick-slip friction characteristics of the abnormal noise parts..The results show that both the rotational speed of the hub bearing side and the torque of the friction model have obvious stick-slip friction characteristics in the initial stage.Then,the influence of system structural parameters such as locking torque,spline stiffness,static and dynamic friction coefficient of the contact surface on the characteristics of stick-slip friction is analyzed.Based on the simulation results of the AMEsim vehicle transmission model combined with the structure of the drive half shaft-wheel hub bearing system,several engineering control abnormal noises are proposed from the three directions of reducing the locking torque,eliminating the conditions for stick-slip friction,and changing the friction characteristics of the contact surface.After comprehensive consideration of cost,Implementation difficulty,suppression effect and other factors,the solution was finally selected to install anti-friction gaskets containing PTFE coating on the abnormal noise part,which successfully solved abnormal ‘click' problem of driving wheel end under the launching condition of the car.