With the rapid development of China’s economy, the proportion of automobile in urban construction, resource exploitation, transportation and daily travel is increasing year by year. In the environment of rapid development of automobile industry, the impact of noise on the overall quality of automobile has become more and more serious, whether from the perspective of relevant national policies and standards or from the perspective of consumers’ attention. On the one hand, consumers have more and more strict requirements on automobile comfort, especially on noise; on the other hand, with the gradual increase of environmental protection, noise, as one of the environmental pollution, is also subject to more strict supervision and control. Therefore, in recent years, in addition to the attention paid to the power, stability and safety of vehicles, in recent years, in addition to the importance of vehicle power, stability and safety, in the car NVH (noise, vibration, harshness) research is also increasing.
The engine, transmission system, brake system, tire and body constitute a complex vehicle system, and each part will produce different levels of noise. Generally speaking, automobile noise mainly comes from engine and transmission system. As one of the most important systems in the automobile, the automobile transmission system does not work independently, and it is often connected with other structural assemblies at the front and rear ends. Therefore, when the automobile transmission system produces strong vibration and noise, on the one hand, it will have a negative impact on the vibration and noise of the whole vehicle, on the other hand, the structural assembly connected with it will also produce correlation reaction, which will be strict At the same time, it will cause unnecessary noise pollution. Therefore, it is necessary to control the vibration and noise of automobile transmission system. In the transmission system, the transmission is the most important structure, so the research of transmission NVH is very important for the research of vehicle noise.
In order to adapt to the complex and changeable road conditions and meet the dynamic requirements of different loads, the working environment of automobile transmission is changing at any time, so the vibration and noise sources of automobile transmission are various. In a transmission, the gear transmission system is the main part of the transmission for power transmission. Its front end is connected with the engine for power input, and the other end is connected with the transmission shaft for power output. At the same time, the whole gear system and the box are connected by the support bearing fixed on the shaft. Therefore, the noise of the transmission assembly mainly comes from the transmission gear transmission system and the box, so the research on transmission NVH mainly focuses on these two aspects.
Taking the manual six speed transmission of a medium-sized truck as the research object, the gear transmission system and case are simulated, optimized and improved respectively, and the effectiveness of the scheme is verified. The significance of the research is to suppress the vibration and noise of this type of transmission, and provide a reference for the study of vibration and noise of similar transmission.