| With the rapid development of China’s automobile industry,people’s attention to environmental protection and health is constantly increasing,and the comfort,reliability,and safety of automobiles especially passenger cars,have gradually became the focus of public attention.The vibration of passenger cars and the noise generated by the vibration not only pollute the surrounding environment,but also endanger the health of drivers and passengers.Due to the distance between the transmission and the drive axle is relatively long,the transmission shaft assembly is generally connected by multiple cross shaft universal joints and two sections.This special structure makes its angle and length constantly change,which inevitably leads to vibration problems in the process of transmitting power.Therefore,studying the dynamic characteristics of the transmission shaft and fundamentally controlling the impact of the transmission shaft vibration can effectively improve the quality of the transmission shaft products and the market competitiveness of manufacturers.This article takes a passenger car transmission shaft as the research object,and analyzes the dynamic characteristics of the drive shaft from the following aspects:(1)The dynamic characteristics of single and multiple universal joints are analyzed,and the influence of the angle between the universal joint shafts on the dynamic characteristics of the transmission shaft is analyzed using Matlab simulation;At the same time,the impact of the additional bending moment and the support reaction force at the bearing on the dynamic characteristics of the drive shaft are analyzed due to the existence of the angle,these Provide theoretical basis for dynamic simulation analysis of drive shaft assembly.(2)ANSYS Workbench is used to establish the finite element analysis model of the drive shaft assembly and perform free modal analysis.The LMS Test.lab software is used to perform free modal experimental analysis on the sample of the drive shaft assembly,and the correctness of the simulation model is verified by comparing the two results.The effects of transmission shaft length,shaft tube thickness,and support stiffness on the natural frequency of the transmission shaft are studied.Based on the analysis of the above parameters and the design process of the transmission shaft,the intermediate support stiffness is determined as the optimization target,and feasible measures for improving the vibration problem of the transmission shaft are proposed.(3)The verified and accurate transmission shaft model was imported into the ADAMS simulation software,and the front and rear shaft tubes were replaced with flexible bodies to establish a rigid-flexible coupling shaft simulation model.According to the actual working conditions,the material properties of each component,the driving pair,and the conditions of the drive shaft assembly are defined,and preliminary verification is performed.Simulate and analyze the dynamic characteristics of the transmission shaft,and verify the correctness of the dynamic simulation model according to the theory of universal joint unequal speed.(4)The parameter optimization design method is used,and the stiffness and damping of the intermediate support is the design variable,and the Y-direction vibration acceleration at the intermediate support is the target value.The influence of design variables on the dynamic characteristics of the transmission shaft assembly at different speeds is analyzed,and reasonable ranges of stiffness and damping are proposed.The influences of the maximum unbalance amount on the transmission shaft vibration is analyzed when the maximum imbalance is located on the different plans of the transmission shaft assembly,and then propose a reasonable optimization scheme to achieve the purpose of reducing vibration and noise of the transmission shaft. |
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