Research On Dynamics Characteristics Optimum Design Of Mini-car Transmission

Transmission is an importance component of automobile, and it's dynamics characteristic has great influence on the whole vehicle's performance. With the people's requirement for more comfortable ride, vibration decreasing and noise absorption have been played an important role in automobile Industry. With the support of Chongqing science technology & commission (project number: CSTC, 2005AC6035), dynamics characteristic of transmission has been investigated, and the research has some academic and practical value.Firstly, the main factors that bring the transmission's vibration and noise are theoretically studied, and the three means of gear motivation are analyzed.Secondly,Considering the drawbacks of existing contact study method, a mini-car gearbox's 4th shift gear system is taken for investigation object. The bear-gear system's three-dimension nonlinear contact dynamics model is presented and 3-D contact nonlinear dynamic characteristic is investigated in this paper. The regularity of dynamic parameters that varying with meshing position, including the contact state,contact stress, tooth root bend stress etc are obtained. The research results settle basis for the dynamic characteristic optimization of gearbox.Factors that influence transmission dynamics characteristic has been discussed, and the tooth profile of 4-shift and constant mesh gear pairs are modified. The dynamic analytical method mentioned above has been re-analyzed. The transient performance of modified gears has improved in analytical results.FE sensitivity analysis technology has been applied to analysis Eigenvalue response sensitivity of transmission box, a dynamics characteristic optimization method has been proposed. By the means of multi-body dynamics simulation, critical working condition is considered, the boundary conditions, such as the forces applying to bears are obtained. On the basis of boundary conditions, the transmission's house transient performance is simulated. it can be provided method to verify optimization results of transmission's house.Finally, modal experiment of mini-car transmission has been carried out, dynamics modification and experiment sensitivity analysis of the transmission can be analyzed on the base of the results. The study will overcome the blindness of dynamics modification, save time, and efficiency is highly improved. In view of experiment, a method of dynamics characteristic optimization is proposed.