Study On The Damping Matching Of Suspension System And Optimizing Design Of Its Components For Electric Vehicle

At present, although electric vehicle study are mostly located in tackling some key technology such as battery, motor and its controlling, we should pay enough attention on suspension system which effect electric vehicle driving safety and riding comfortableness. Some statistics has shown that nowadays fuel vehicle parameters are directly transplanted electric vehicle suspension system design parameters, it’s not matching design on suspension system according to electric vehicle practical parameters, so electric vehicle suspension system parameters can’t meet people’s requirements of safety and comfortableness. Theory of damp matching and designing of three composition parts were studied, aiming at the existing problems. The innovations are as follows:(1) Based on suspension offset frequency formula, static and dynamic deflection were referenced as terms of restriction,suspension expression was buit, to consider the suspension lever ratio and spring mounting angle of the premise, stiffness analytic formulas of coil spring was established. According to two methods of proportion middle term method and average method about main and assistant spring stiffness design and distribution, the main and assistant spring stiffness analytic formulas of coil spring were respectively built, the parameter formulas were determined; the practical design of spring was done with proportion middle term method.(2) With single wheel two freedom driving vibration model and differential equation, by objective function of wheel dynamic load and body vibration response mean square value, the vehicle suspension system optimum damping ratio mathematical models were respectively established based on driving safety and ride comfort, the optimal damping matching optimized design mathematical model of electric vehicle suspension system was established by the golden section method.(3) By analysis on the condition of real force on throttle-slice, the mechanical model of throttle-slice under non-uniform distributed pressure was established, based on elasticity theory, the deformation analysis formula was built, the deformation coefficient of throttle-slice under non-uniform distributed pressure was obtained, the matching design of restoration valve and compression valve was realized, practical design and absorber performance test were done.(4) With superposition principle, the superposition mechanical model of rubber bush was built, based on elasticity theory, the radial deformation analysis formula of rubber bush was established, according to the second cassette theorem, the deformation analysis formula and the diameter optimization mathematical model of stabilizer bar based on rubber bush were established.The damping ratio matching and three parts practical design for one kind of Shifeng electric vehicle suspension system was carried out, by absorber performance tests, the results show that the matching design of absorber is accurate reliable, it can meet the whole vehicle performance requirement. This study has important theoretical and application value for the matching design of electric vehicle suspension.