Key Parameters Matching And Vibration Optimization Research Of Shaft Intermediate Support

The drive shaft in the variable axial transmission system is one of the most important subsystems of the vehicle chassis.The power output varies with the non-uniform and additional bending moment of the U-joints and other non-linear factors,to some extent,the unreasonable parameters match can lead to the increasing vibration amplitude of the shaft and rear axle.The shaft intermediate support has great influence on the vibration response of the shaft and the energy-saving and noise-reduction of a shaft-final drive assembly.To this issue,the parameters match characteristics between intermediate support and shaft-axle system was considered,the viscoelastic characteristics of elastic support component and its nonlinear static and dynamic stiffness characteristics were studied by the Finite Element Analysis(FEA),and its variable stiffness change interval was discussed by the theoretical analysis and experiment.Then a 11-DOF non-linear coupled vibration model was established to analyze the influence of stiffness change interval on the dynamics of theshaft-finaldriveassembly.Bytheoptimizationanalysisand experiment verification,the results show that the system fluctuation values can be decreased effectively when the axial stiffness of the intermediate support is K_x?[50,55]N/mm,and the radial stiffness isK_z?[65,75]N/mm.The major contents are listed as follow:Based on the rubber isolation mechanism,the material mechanics theory was adopted to deduce the axial and radial deformation rule of the support bearing,the Abaqus software can be effective to simulate the static and dynamic stiffness characteristics of rubber bearing.By the comparative analysis of simulation and test supported by SAIC-GM-Wuling Automobile Co.,Ltd,a region of stiffness change interval could be determined.The 11-DOF non-linear coupled vibration model of the shaft-rear axle system was established by employing the lumped mass method so as to identify the coupling effects of the bearing stiffness to the vibration response of the shaft-final drive system.the intermediate support was simplified as the axial and radial spring-damping system,the engine's torque ripple,the alternating load from the U-joints as well as the time-varying mesh parameters of hypoid gear were also considered for accurate quantitative analysis.By the equivalent principle and numerical analysis,the influence of different intermediate support stiffnesses on dynamic response of the shaft and gear system were analyzed at the given speed and the different speeds.With the UG and ADAMS software,the dynamic model from U-joints to rear axle was built to study the influence of intermediate support stiffness on the speed and torque output fluctuations and system performance at the given speed and the different speeds,a region of support optimized stiffnesses of the drive shaft which could improve the system performance were obtained.Finally,the initial and optimized drive system were tested by the experimental platform,then LMS test system was adopted to the vehicle noise test.The correction of the theoretical analysis was validated by the experimental verification.It provides certain theoretical reference for the optimal design of intermediate support stiffness to realize the vibration and noise reduction.