Research On Kinematics/Dynamics Analysis And Acceleration Life Prediction Of Multi Stage Planetary Gear Reducer

The multi-stage planetary gear reducer is one of the important components of concrete transportation mixer trucks.Due to the complex operating conditions and large load fluctuations,it is easy to cause abnormal damage to the reducer.Therefore,it is necessary to conduct load tests on the reducer to test its working performance and reliability indicators.But the testing time of the gearbox is long and the cost is very high.Therefore,this project proposes an accelerated life prediction test method,which can not only meet the test requirements but also accelerate the test process.It is of great significance for shortening the test time,reducing test costs,and accelerating product launch to the market.The main work and innovative conclusions in this paper are listed blow:Based on the domestic manufacturing level and processing capacity,first,the structural composition and working principle of the concrete mixing transport vehicle were briefly described,and the general layout plan of the high speed ratio planetary gear reducer was selected and verified;then,an optimization model of the transmission ratio for the large-ratio planetary gears was established,and the optimal matching of all levels of transmission ratios was completed by using MATLAB;finally,the 3D solid modeling and prototype trial production of the reducer were completed,which provides the theoretical model and prototype for its subsequent dynamic analysis,numerical simulation,and experiments.After a brief analysis of the main factors affecting the performance of the reducer,the kinematics/dynamics equations of the planetary gear transmission system were established,and the corresponding solution methods were given;then the kinematics/dynamics simulation models were established in Adams;subsequently,based on the loading conditions and the requirements of the "Test Methods for Earthmoving Machinery Reducers"(JB/T 9721-2015),the analysis plans for the constant speed with variable torque and the constant torque with variable speed were designed,and simulation analysis was completed.The effects of factors such as tooth transmission error,time-varying meshing stiffness,meshing in and out impact,and inter stage transmission error on output torque and component load were discussed,which will be helpful for subsequent static strength analysis Accelerated life prediction provides basic data and theoretical guidance.Based on the requirements of the bench test,a mathematical model for the accelerated life test of the gearbox was first established,and then the method for compiling the load spectrum of the accelerated life test and the testing method for the accelerated life were determined;then,by using the Ansys software and quasi-static analysis method,the stress levels and distribution status of key components were identified such as sun gear,planetary gear,gear ring,and planetary shaft under different external loads were analyzed,and then the weak aspects of each key component in the reducer were found;finally,a test plan for accelerated life testing was verified according to the weak components.The experimental results indicate that the accelerated life prediction method is feasible and equivalent to conventional fatigue operation tests and overload operation tests.It can greatly accelerate the testing process,effectively reduce testing costs,accelerate the speed of product introduction to the market,and provide more selection routines for the design of similar product testing schemes in the future.