Research On Fatigue Life Analysis And Prediction Method Of Electric Vehicle Gear Reducer

With the increasing maturity of battery motor electronic control technology,electric vehicles have gradually entered our lives.For electric vehicles,most of the existing researches are about the design and optimization of three-electric technology or the reducer of electric vehicle parts.Few studies on the fatigue life of electric vehicle reducers.At present,most electric vehicles still use a motor plus a fixed speed ratio reducer.Once the reducer fails,the electric vehicle will not be able to travel,so the fatigue problem of the reducer of the electric vehicle is very important.However,the fatigue problems of electric vehicle reducers are different from those of conventional gasoline vehicle reducers in terms of load spectrum,load characteristics,and fatigue life analysis and prediction methods.They cannot be copied from the data and methods of traditional gasoline vehicle fatigue problems.In response to the above problems,this article first collected the power source output torque and speed of a certain electric vehicle and fuel vehicle in a test field.Based on these data for analysis and comparison,it was pointed out that the output torque of the electric vehicle motor has high frequency oscillations and fluctuations,Due to the high speed of the motor and the single gear of the fixed speed ratio reducer,there will be a large number of small loads in the load of the electric vehicle reducer.Secondly,in view of the characteristics of gear meshing and the characteristics of fast output speed of the motor and large frequency of output torque fluctuation,it is pointed out that the traditional rain current counting method is not suitable for the processing of the load spectrum of the electric vehicle reducer.In this paper,the rotating rain current counting method is used to process the load spectrum of the reducer,which can record the load cycle history of the reducer relatively completely.Then,the gear torque load spectrum is converted into the tooth surface contact stress load spectrum by the contact stress calculation formula.Based on this,the influencing factors of the nominal stress method,Carten-Dolan theory,and local stress-strain method are studied,and these three methods are used to analyze The life of the reducer gear is determined through a comparative analysis to determine the fatigue life analysis method most suitable for electric vehicle reducers.Finally,in view of the shortcomings of the existing fatigue life prediction methods,an improved life prediction method is adopted to make it suitable for the fatigue life prediction of electric vehicle reducers.