| Auto transmission includes its internal gear transmission system and the shell. Gear transmission system, the most important power and transmission forms for machinery and mechanical equipment, now is wildly used in many fields of national economy, especially in auto power transmission systems, gear transmission system is the key component to realize speed and power transmission. The shell is support structure, which also play a role in cooling and lubrication for internal gear transmission system, its structure must be designed to save space and reduce weight.It will be the final aim with the high development of the modern industrial technology that the gear transmission system gets the high speed, highly efficiency and brute force. Vibration and noise of the gear transmission system have become a paramount problem increasingly because of the high power and speed of the gear transmission system. In the automobile industry, this is mainly embodied in the study of auto transmission NVH(Noise, Vibration, Harshness) characteristic, the article research dynamics characteristic of automotive transmission which affects the NVH characteristics.Dynamics of auto transmission mainly affected by the internal gear transmission system and the shell, therefore, the dynamics problems of auto transmission is essentially divided into three part which include the shell dynamics problems, internal gear transmission system dynamics problems and the two part’s coupled model dynamics problems.In this paper, automotive transmission is for research, completed the three-dimensional modeling and the virtual assembly of the automotive transmission and its main parts by SolidWorks software. In the finite element software ANSYS gears were simplified as two cylindrical which were connected by the coupling matrix, bearing was simplified as spring element, through finite element analysis and stress analysis the time-varying meshing stiffness and bearing stiffness of transmission on the specific operating condition were obtained. On this basis, the paper constructed gear transmission system and transmission assembly finite element model. Through finite element analysis, the mode of transmission case, the transmission system and transmissons are analyzed.The internal excitation of transmission includes stiffness excitation, error excitation and meshing shock excitation. It was obtained by finite element contact analysis, error equivalent method and finite element simulation. Then the dynamic response analysis of gear transmission system in internal dynamic excitations is processed. The whole transfer matrix method is suitable to analyze dynamics property of multi-rotor system. Dynamics equations of gear pair are deduced here. The paper established the third bevel gear coupled unit transfer matrix and the support of the shaft section of the node transfer matrix. The mode of input level transmission system (including input shall and output shall) is analysis by lumped parameter method and finite element analysis method, contrast of the two results shows they are good agreement. |
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