| Transmission is an important part of the drive line system, it has a direct impact on thevehicle stability and ride comfort. As the rising demand for passenger cars year by year andthe pursuit of comfort, the demand for the cars with automatic transmission is increasing.The Dual-clutch transmission combines the advantages of the hydraulic automatictransmission and mechanical transmission, such as improving fuel economy andeliminating the shortcoming of shifting power interruption. And the long termaccumulation of machining capacity and human resources on the mechanical transmissionindustry can be fully used. On the background of advocating independent research anddevelopment on China auto industry, the study on the Dual-clutch automatic transmissionis particularly important.In the paper, the Dual-clutch of transmission of Shanghai SICAR Vehicle TechnologyDevelopment Co., Ltd is for research. On the base of Multi-body Dynamics Theory andFEM, the structural strength, the dynamic excitation and the dynamic response areanalysed. The radiated noise of the transmission is predicted through using BoundaryElement Method. At last the optimal design of transmission system is obtained on the studyof the gear parameters and modification of tooth profile, the vibration and noise is reducedwith the transmission error reduction.The research work presented in this thesis can be summarized as follows:(1) The geometry model, finite element model and the simulation model of theDual-clutch transmission are built. The structural strength of transmission housing andshaft are analysed, and the working life of gear and bearing is predicted.(2) According to Machinery Dynamics and Gears System Dynamics, the torsional vibration model of Dual-clutch transmission is built. The modes of the transmissionhousing and transmission system are analysed through using the method of Lanszos, thenatural frequency and vibration modes are obtained. And the influence of the bearingstiffness on the modes of transmission is researched.(3) Using the gear system dynamics theory, the dynamic characteristics of meshinggears is analysed on the study of tooth stiffness excitation, error excitation and meshingimpact excitation, the dynamic excitation curve is obtained. The results of vibration arecalculated by means of mode superposition method in transient response analysis moduleof NASTRAN. By Fast Fourier transform, the vibration values are transformed to thefrequency domain responses which act as the boundary excitation condition. Thetransformed vibration values are imported to acoustic boundary element model, and thenthe radiated noise of transmission is predicted.(4) By studying the transmission gear parameters which effect the vibration and noise,the optimal design is proposed and the vibration and noise is reduced with modification oftooth profile. |
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