Research And Application Of The Variable Stiffness Coil Spring On Crossover Rear Suspension

As an important elastic component in automotive suspension system,the coil spring plays a role of absorbing vibration,which affects the vehicle ride comfort.With the higher requirements on the vehicle ride comfort,improving the vibration reduction effect of the coil spring and reducing the vibration in driving have become an important direction to improve the performance of the vehicle.The constant stiffness coil spring which is used in a certain type of crossover can not meet the requirements of the vehicle ride comfort,and it is proposed to improve the ride comfort of the whole vehicle by using variable stiffness coil spring to improve the rear suspension.Thus it is very necessary to carry out research on the variable stiffness coil spring of this type of vehicle.In this paper,the research on the variable stiffness coil spring of the vehicle is mainly carried out as follows:Firstly,with the original constant stiffness coil spring as the object of study,the necessity of the study on the variable stiffness coil spring is obtained through starting with the frequency domain analysis of linear vibration of the suspension.Secondly,in order to acquire the structure parameters,the drum type variable stiffness coil spring is measured,and then the corresponding relationships of parameters are derived.The stiffness characteristics of variable stiffness coil spring are calculated by using the method of discretization,moreover,the effects of parameters on the stiffness of the coil spring are studied.Thirdly,the three-dimensional model of variable stiffness coil spring is established by using MATLAB and Pro/E,and then stiffness characteristics,strength,natural frequency and fatigue life of the variable stiffness coil spring are studied with finite element analysis of variable stiffness spring by using Workbench,moreover,the coil spring compression text is designed to verify the results validity of the theoretical calculation and finite element analysis,and the MATLAB is used to get the mathematical model of the characteristic curve by fitting the stiffness characteristic curve.Then,in order to analyze the vibration response of the vehicle body under different conditions,the nonlinear vibration simulation model and the linear vibration simulation model of the rear suspension are established by using Simulink according to the actual structure of the rear suspension,and then the ride performances of the two kinds of coil spring suspension system are discussed,furthermore,the subjective evaluation of road tests are designed to verify the reliability of simulation results.Finally,The anti-resonance mechanism of the variable stiffness coil spring and its effect on the suspension design space are analyzed.The results show that the variable stiffness coil spring can effectively improve the vehicle ride comfort without increasing the suspension design space.The research of this paper provides a certain technical support for the application of variable stiffness coil spring on this vehicle,which will decrease vibration,reduce noise and improve the vehicle ride comfort.