Transmission Efficiency Research On Automobile Fixed Constant Velocity Joint

In an automotive driveline,a driveshaft system is used between the differential or reduction gear and the wheels to transmit motion and power.The torque transfer efficiency of system has always been a hot topic of research.Compared with the torque loss of the engine and transmission,the torque loss of the drive shaft is relatively much smaller.But with the major car companies paying attention to the drive shaft transfer efficiency,there have been some related researches in recent years.In this paper,the torque transfer efficiency of different CVJs and under different operating conditions are compared experimentally for a ball-cage universal joint.Then a multi-body dynamics model is established,and a simulation analysis is carried out to obtain some kinematic and dynamical conclusions.At the same time,the parametric dynamics model is explored to simplify the model development process.On the basis of the parametric model,scripted simulations are carried out to automate the simulation process.So the same model does not require frequent adjustment of working conditions and geometrical parameters during the simulation process.Further,based on the parametric modelling and scripted simulation,a response surface model is developed to investigate the influence of the geometrical parameters and operating conditions on the torque transfer efficiency,and to obtain a predictive model for the torque transfer efficiency.The response surface prediction model is then used to optimize the dimensional parameters for better transfer efficiency,which is of guidance to the design of ball-cage constant velocity universal joints.The main work of the dissertation is as follows:(1)A discussion of the drive shaft system and the structure of the ball-cage universal joint.The principle of the torque transfer efficiency bench test is explained.Then a bench test plan is designed to determine and compare the effect of different operating conditions and structures on the torque transfer efficiency.A bench test is carried out on the high-efficiency ball-cage universal joint and the common joint under different working conditions.The differences in the number of raceways and raceway shapes are compared and analyzed,and the effects of different structures and working conditions on the torque transfer efficiency are obtained.(2)Exploration of parametric modelling and scripting simulation of ADAMS multi-body dynamics simulation software.Firstly,a three-dimensional model of the ball-cage universal joint is established in ADAMS,and constraints and loads are added to obtain a multi-body dynamics model,which facilitates the reduction of test costs.The parametric model simplifies the subsequent development of the multi-body dynamics model and facilitates scripted simulations,while the scripted simulations automate the simulation process so that the same model does not require manual adjustment of operating conditions and geometric parameters during the simulation.So all the required data can be obtained in a single simulation.After obtaining the parametric multi-body dynamics model,a bench test is conducted to verify its accuracy.(3)A comparative analysis of the internal ball motion and contact forces between the highefficiency ball-cage type and the common universal joint.This paper analyzes the dynamics of this type of joint to obtain the advantages of this structure.The internal motion and friction losses on the raceways of the high-efficiency and normal joint are investigated through the multi-body dynamics model,.The effect of the combination of straight and circular raceways on the torque transfer efficiency is discussed.(4)Combined with the simulation results of the parametric model,a multi-factor response surface prediction model is developed for the dimensional parameters.The influence on the torque transfer efficiency is analyzed and optimized.The principle of the response surface model is explained,and the key dimensional parameters are selected for the study.Combined with the parametric multi-body dynamics model,the effect of certain key dimensional factors on the torque transfer efficiency,is quickly and effectively derived.On this basis,the key dimensional parameters of the high-efficiency joint FEJ-U are optimized to a certain extent.