Torsional Vibration Analysis And Optimization Of Vehicle Transmission System With Front And Rear Drive

With the advancement of scientific and technological development level,the automotive industry has entered an era of rapid development,people are increasingly demanding automotive safety and comfort,and car manufacturers are also increasing their attention to automotive NVH performance.With the continuous development and sales increase of front-and rear-drive multi-purpose vehicles(MPVs),the vibration and noise problems and impacts caused by the large-power engine of this kind of car are particularly prominent.Therefore,the research,analysis and solution of these problems have become an important topic in the development of this kind of vehicle.This article studies the vibration and noise of an MPV model.The main research contents are as follows:(1)Aiming at the roar of the front and rear drive MPV cab,an automobile cab vibration and noise experiment and a car transmission system torsional vibration experiment were carried out.The reason for the roar of the cab and the engine speed corresponding to the resonance were analyzed through experiments.which provided the experimental verification basis for theoretical research and simulation analysis.(2)The power transmission system components of the front and rear drive MPV were analyzed and simplified,and the equivalent analysis model of the complete vehicle transmission system with 19 degrees of freedom was established;According to the model,the free vibration model of the power transmission system was established,and the natural frequency and mode of vibration were analyzed.At the same time,the forced vibration model of the power transmission system was established to analyze the stimulated response law of the input end of the transmission and the main reducer;The two vibration models were simulated and analyzed,and the results of the experiment were compared with the data obtained from the simulation analysis.The error between the two was within the allowable range,which verified the effectiveness of the two analysis models.(3)According to the free vibration model,the parameters of the main components of the power transmission system were analyzed for free vibration;According to the forced vibration model,the sensitivity of the forced vibration was analyzed,and the variation of the main parameters of the system,such as the inertia of the flywheel,the rigidity of the clutch,the damping of the clutch,the rigidity of the transmission shaft,the ratio of the final drive and the rigidity of the half shaft,on the torsional vibration response of the input end of the transmission and the input end of the final drive were analyzed.(4)According to the sensitivity parameter analysis,the four parameters of flywheel inertia,clutch stiffness,clutch damping and half shaft stiffness,which have a great influence on the power transmission system,were selected for optimization.The vibration effects of installing elastic couplings at different positions of the system were analyzed.The vibration effect of the transmission shaft end of the power transmission system is obviously reduced by the optimization analysis.