Noise Analysis And Optimization Of Electric Vehicle Transmission Based On Multi-objective Topology Optimization

In recent years,with the advancement of the electric vehicle industry,customers have become more stringent in their requirements for vibration and noise.The different structures of electric vehicles bring new NVH problems.Therefore,research on vibration and noise of electric vehicles is of great significance.This paper takes a four-speed automatic mechanical transmission equipped with a self-owned brand electric vehicle as the research object,and carries out the optimization of transmission vibration and noise.Conduct research on vibration and noise testing of electric vehicles.The order spectrum analysis is used to analyze the influence of motor and transmission noise on the interior noise of electric vehicles under accelerated conditions and uniform speed conditions.A gear with severe vibration noise is determined.The main components that affect the noise level in the car are determined,and data support is provided from the source to reduce the noise level of the electric vehicle.Conduct research on transmission vibration and noise bench experiments in a semi-anechoic chamber.According to the industry standard design vibration and noise bench experiment of the transmission,the measured vibration and noise signals are identified and analyzed by the spectrum analysis method.The characteristics of transmission vibration and noise are analyzed,and the main gears and positions of noise generated by the transmission are clarified.This provides a basis for the subsequent simulation and optimization of the transmission.Carry out frequency response simulation and modal research of the transmission.The experimental mode and simulation mode of the transmission case are obtained through experiments and CAE simulation.The accuracy is verified by comparing the modal frequencies of the experimental modalities and the simulated modes and the errors of the modes.Pick a reference point at the front of the transmission.The vibration acceleration at the four bearing seats of the transmission was applied as an excitation to the finite element model of the transmission,and the vibration frequency response simulation analysis was performed using the finite element software Radioss.The transmission housing vibration frequency cloud map and the acceleration frequency response curve at the reference point will be obtained.Carry out research on multi-target topology optimization of transmission housing.Considering the analysis results of the simulation results of the vibration frequency response of the transmission,the vibration peak is used as the sub-objective of the topology optimization,and several sub-objects are associated by the multi-objective function to form the total objective function.The design area is determined based on the vibrational cloud map and the feasibility of the transmission housing casting process.The transmission housing model was modified based on multi-target topology optimization results,and a new transmission housing was obtained using 3D printing technology.The optimized housing and gear system were assembled and subjected to vibration and noise experiments.Compared with the unoptimized transmission,the vibration acceleration at the reference point of the transmission was reduced by 1.6 m/s~2 and the noise was reduced by 2.2 d B.The optimization scheme has a good effect.