Vibration Noise Analysis And Experimental Study Of High Speed Differential Gear Reducer For Electric Vehicles

In the automotive industry,with the increasing consumption of non-renewable energy,new energy vehicles represented by electric vehicles have turned into the crucial development direction.The differential reducer for electric vehicles is driven directly by the motor,which makes the drive system structure more compact.Compared with traditional vehicles,the engine and exhaust system with the largest contribution to noise are eliminated.However,due to the high input speed of the motor,the howling noise generated by the differential gear transmission system during high-speed meshing becomes the main noise source of the drive system.In this thesis,the high-speed differential reducer of electric vehicle was considered as a research object.The dynamic model of the differential reducer was built.The internal excitation was calculated and analyzed.The influence of different speed and load conditions on the vibration and radiation noise of the housing was studied.And the vibration and noise experiment of the differential reducer was carried out.The research results have certain theoretical significance and engineering value for realizing the vibration and noise prediction and control of high speed differential reducer gear transmission system.The main contents of this dissertation are shown as follows:(1)Based on the transmission principle and structural analysis of the electric differential gear reducer,the MASTA professional calculation software was used to establish the coupled analysis model of the differential reducer system with the flexibility of the differential reducer box,and the main internal excitation meshing stiffness and transmission error that cause the vibration and noise of the housing were calculated and analyzed;(2)The modal analysis model of the differential reducer housing was established by a software called LMS Virtual.Lab,and the natural frequency and mode shape of the housing were calculated and analyzed.Based on the analysis of the dynamic response of bearing capacity to the bearing load,the effects of the rotational speed and torque conditions on the vibration response of the box were studied;(3)Based on the acoustic boundary element method,the LMS Virtual.Lab software was used to generate the box acoustic boundary element surface mesh.According to the ISO standard,the field point grid was set up in the space distance of 1 m from the housing,and the radiation noise calculation model of the differential reducer housing was established.The influence of speed and torque condition on the acoustic noise of the field of differential retarder was studied;(4)Using the vibration test platform of the differential reducer,the experimental research on the differential reducer was carried out.The vibration of the housing under different input conditions was tested.The sound level meter was used to measure the noise in the upper,left,right and rear direction of the housing.The correctness of the theoretical conclusions were verified by comparing the test results and the theoretical calculation.