Research On Vibration And Noise Analysis And Optimization For Transmission In Pure Electric Bus

In the electric drive system of electric vehicle,the transmission is directly connected with the motor,and the motor replaces the engine.The transmission noise becomes more and more obvious due to the lack of masking effect of engine noise.In addition,with the increase of motor speed at this stage,the vibration and noise of the transmission,especially the highfrequency squeal,become more and more seriousAs an important transmission component,gear is widely used in industrial production.Although people’s research on gears has been quite mature,the development of computer technology has gone beyond the stage when people study gears based on experience summary.In particular,the emergence of some gear professional software makes the design and analysis of gears more convenient,faster,more accurate and reliable.According to the existing theory,this paper analyzes the internal and external causes of transmission vibration.The internal gear transmission system generates vibration in the process of meshing,which is transmitted to the box body through the shaft,bearing,and then stimulates the box body to generate noise radiation and transmit it to the human ear,making the driver uncomfortable.Therefore,in this paper,KISSsoft software is used to model the dynamic analysis of the transmission gear transmission system,study its dynamic characteristics and analyze the influence of the center deviation,the deformation of the gear shaft,the parameters of the gear transmission system and the inherent characteristics of the gearbox on the vibration and noise characteristics of the transmission,which is of great significance for the design of the guide transmission and the reduction of the noise of the transmission.In the gear analysis module of KISSsoft,the influence of macro parameters such as pressure angle and helix angle of gear pair on meshing stiffness is studied.The results show that the helix angle has a great influence on the meshing stiffness,while the pressure angle has a small influence.The larger normal modulus is beneficial to reduce the meshing stiffness fluctuation,but it should not be too large.According to the above research,choosing reasonable gear macro parameters can effectively reduce the meshing stiffness.In KISSsoft,the dynamic model of the gear system is established.Based on this model,the influence of the center deviation of the gear pair and the deformation of the supporting device on the meshing performance of the gear is studied.The load distribution and meshing transmission error of the gear system with the flexibility supporting device are calculated and analyzed.These calculation and analysis make preparation for the later gear modification.By using the gear modification function of KISSsoft,the influence of different modification methods and amount on the transmission error is analyzed.Among them,the modification of tooth top flange and tooth end has obvious effect on reducing the peak value of transmission error.According to this conclusion,the gear with constant mesh is modified to obtain the optimal solution,and the load distribution and temperature distribution of the gear tooth surface are analyzed.The results show that the optimization scheme has an obvious optimization effect on improving the load distribution and reducing the temperature of the gear tooth surface.By using Hypermesh,the finite element model of the box is built and its natural frequency is analyzed,and the frequency response is optimized.Through the use of software to optimize the structure of the box and change its natural frequency and to avoid coincidence with the vibration frequency of the gear system.The results show that the optimization method in this paper has obvious optimization effect on the transmission.Compared with the noise and vibration test results before and after optimization,the overall vibration noise of the transmission is effectively controlled.