At present, great attention has been paid to the control and research of transmission vibration and noise at home and abroad. From the perspective of research direction, it can be roughly divided into: the research and control of the vibration and noise of transmission case and gear transmission system, the research on the mechanism of transmission vibration and noise, and the formulation and development of transmission vibration and noise related test scheme and test system Research on knocking noise and gear whine of transmission. In addition, some achievements have been made in the research of the materials which can better control the noise of the transmission assembly.
The control of vibration and noise in automobile transmission is regarded as a key factor to measure the comfort level of vehicle performance. NVH control and research should be regarded as an important evaluation index for a transmission from design and development to manufacturing. At present, foreign automobile manufacturers have their own vibration and noise laboratories to carry out NVH research on transmission. On the one hand, in order to meet the increasing noise standards or regulations and optimize the noise of the whole vehicle and its parts, on the other hand, they carry out tests for the research and development of transmission. At this stage, the development and investment of major automobile manufacturers in NVH have reached a certain level, at the same time, their research level has also reached a certain height. At present, there is a big difference between domestic automobile manufacturers and developed countries in terms of NVH. Due to the relatively late development of the domestic automobile industry, until the beginning of the 21st century, there have been a number of manufacturers and institutions to study the vibration and noise of vehicle and parts. In recent years, with the improvement of relevant theoretical level and in-depth research, a large number of domestic automobile transmission manufacturers and automobile manufacturers began to invest a lot of energy on the NVH problem of transmission. However, at present, most of the domestic analysis and test systems for vehicle transmission vibration and noise are purchased from abroad, and the core technology of auxiliary software and equipment for vibration and noise research is still blocked.
In the early stage, based on the linear vibration theory, many scholars have carried on the thorough research to the gear system. In recent ten years, experts at home and abroad have gradually turned their attention to the nonlinear vibration theory. Based on the time-varying meshing stiffness and backlash, the nonlinear vibration of the gear system is tested and discussed.
At home and abroad, the research on the vibration and noise problem of automobile transmission only depends on the test improvement at the initial stage, and gradually transits to using a variety of high-end equipment and means to test and simulate the noise. At present, the relevant theory and test system have been gradually improved in solving the problem of transmission vibration and noise. At present, the research on transmission vibration and noise is mainly divided into two directions, one is based on test, the other is based on computer-aided simulation.
As for the test and analysis of automobile transmission, the transmission structure is often tested and analyzed by advanced test equipment and test theory. Nowadays, as one of the most common technologies used in transmission vibration and noise related test, compared with the traditional testing technology, acoustic testing technology has lower requirements for anechoic chamber and does not need special acoustic environment. It is very effective for field test, especially for noise source test. However, the transmission test research in high precision at the same time, its related instruments and equipment are often very expensive, at the same time, the test time span is large, so if only through the test method for research, it will take a long time from finding out the problem to solving the problem, it is difficult to meet the research and development needs of transmission products, so the computer is used as an assistant hand The simulation research of segment is gradually derived. At present, the theoretical system and technical means of transmission vibration and noise simulation research abroad are more perfect than those at home, especially in the application of finite element method (FEM) and boundary element method (BEM) in transmission. On the basis of improving the theoretical system, foreign countries have gradually developed and perfected some targeted and powerful simulation software to assist simulation analysis.
When analyzing the vibration and noise of a transmission, Howard et al. Further improved the modification parameters by analyzing the tooth profile modification scheme of the gear in the system, so as to achieve the goal of reducing the vibration and noise of the transmission. Rigaud et al. Studied the transmission gear transmission system and case, on the one hand, studied the causes of transmission vibration and noise, on the other hand, obtained the conclusion that there is mutual influence between the vibration noise generated by transmission work and the gear parameters, bearing stiffness and manufacturing and assembly errors in the transmission system. M. Barth et al. Applied harmonic load to the transmission gear system, and studied the vibration and noise problems through experiments. J. By optimizing the gear design parameters, and calculating and analyzing in time and frequency domain, Tuma proposed the concept of the contribution of the transmission gear system to the whole, and finally verified its rationality.