Simulation And Analysis Of Vibration And Noise Of Reducer Of Electric Vehicle

Electric vehicles are the trend of future automobile development in the world,and the research on electric vehicle reducers is also gradually carried out.Aiming at the reducer of an electric vehicle,this article applies the hybrid dynamics theory to construct the theoretical model of the two-stage helical gear transmission of the reducer.The method of combining theoretical model and software simulation is used to simulate the vibration response and noise radiation of the transmission system,and the actual vehicle test is carried out.The specific research process is as follows:(1)Aiming at the wide rotation speed characteristics of electric vehicle reducers,the dynamic characteristics of the helical gears are accurately modeled by using the concentrated mass method.Based on its torsional vibration model,through the Timoshenko beam model in structural dynamics,combined with the rotor dynamics theory,a two-stage gear-rotor-bearing hybrid dynamics bending-torsion shaft pendulum dynamics model was constructed.The theoretical model is used to study the effects of rotational speed excitation within 12000 rpm and parameter excitation including position angle,intermediate connecting shaft length,and meshing stiffness of two gear teeth on the dynamic characteristics of the transmission system.And The dynamic meshing force is used to evaluate the vibration characteristics of transmission system.The results of the speed excitation show that the gearbox will have a unilateral meshing shock due to the gear meshing frequency being close to the common frequency of the system at high speeds,which will increase the vibration.The parameter excitation results show that the reasonable setting of related parameters can reduce a certain dynamic meshing force,thereby reducing vibration.(2)two-stage gear transmission was established through ADAMS.The model considered the gear meshing and bearing stiffness effects.The simulation results obtained the numerical change curve of the gear meshing force,and the bearing force numerical change curve of the gear shafts at all levels.The study found that the system has obvious gear order characteristics,and there is a vibration enhancement phenomenon near the important frequency band.(3)The restraint modal analysis of the reducer shell model was carried out,and the natural frequency and mode shapes of the first 12 steps of the reducer shell were obtained.The vibration and noise simulation of the reducer shell was performed.There are peaks in vibration and radiated noise on the surface of the shell under modal frequency,and the structural improvement of the reducer for the modal shape will help to reduce the benefits of noise and vibration.(4)The real vehicle experimental test of the reducer was conducted.The experiment collected and analyzed the noise in the vehicle at 1000 Hz and the gear vibration acceleration in the vertical direction of the vehicle.The comparative analysis with the theoretical results shows that the gear’s vibration trend in the experiment is consistent with the theoretical test trend,and the casing noise has a common peak noise at the first-order natural frequency of 750 Hz..