Research status of transmission vibration and noise in China

China started to pay attention to transmission vibration and noise relatively late, and the early main direction focused on the reduction of transmission noise. Through the test of the transmission reverse gear produced by Beijing gear works, it is found that the knocking noise of the transmission is mainly caused by the large period error of the gear teeth under the low speed condition, and the noise intensity level increases mainly due to the small period error of the gear teeth. The noise can be reduced by controlling the profile curve and gear accuracy before and after heat treatment. E Zhongkai and others carried out experimental analysis and theoretical calculation for a light vehicle transmission, and finally found the noise source of the transmission. Then, through the improvement of heat treatment process of the transmission gear and the method of adding axial stiffener to the box, the noise reduction was carried out, and good results were obtained.

By modifying several common gears, Liu Dezhao found that the transmission error and transmission noise of gears with the same accuracy level are affected by the tooth profile curve, so the noise can be suppressed by adjusting the optimal tooth profile. In the same year, Feng Zhendong of Jilin University of technology and others established a mathematical model for the knocking of transmission gears at idle speed. Through the comparison of calculation and test, the prediction method of sound pressure level of transmission under idle condition was put forward. Then, Chang Wenxiang et al. Weakened the vibration source and vibration transmission path, calculated its natural frequency with the help of finite element method. Finally, through coating organic materials on the surface of transmission case, the vibration energy was converted into heat energy, and the bearing related parts were properly treated to achieve the purpose of noise reduction of automobile transmission assembly.

Chinese scholars have made further research on transmission vibration and noise, and have made some achievements in the research and control of transmission noise and the optimization of transmission noise test methods. On the one hand, the noise of transmission comes from the impact of gears, on the other hand, it is related to the structure and characteristics of transmission case. Xu Xiangnong et al. Combined with the mechanism of vibration and noise, established the mathematical model of optimization design of high-grade gear noise reduction to optimize the design of gear pair, and achieved ideal results. In the same year, Xu Xianfeng found that the gears in the transmission assembly produced low-frequency noise and the box produced high-frequency noise. By optimizing the weak link of the box, the noise could be reduced. When testing and analyzing the transmission of an automobile, Jin Yezhuang et al. Found the noise source and frequency range of the transmission by using the method of combining sound intensity, sound pressure and vibration. In the same year, Wang Jianjun, Li Runfang and others discussed the characteristics and parameter laws of transmission under nonlinear vibration. Pei Ling et al. Proved the feasibility of reducing noise by gear modification by discussing the calculation process of gear modification.