The Influence Of Hydraulic Damper’s Structure Parameters On Its Performance

With people’s living standard continue to improve, the pursuit of the quality of automotive products is getting higher and higher. Comfortable, safe, car products with small noise are more and more popular. Hydraulic damper is a kind of vibration damping device which is widely used in automobile chassis, its performance directly affects the stability and comfort of the vehicle, so the dynamic characteristics of the vibration damper are more and more concerned by the manufacturer. At present, the imported hydraulic shock absorber price is relatively high, the maintenance cost is expensive. Domestic research of vibration damper started late, and the domestic hydraulic shock absorber has a big gap in the performance of the hydraulic shock absorber compared with the foreign, so most of the vibration absorber are dependent on imports. The traditional absorber design method is modify its structure parameters through experience and produce a new prototype tested on the test-bed, and then repeatedly adjust the structure size. Such repeated experiments, not only it have a long development cycle and high cost, but also it is difficult to obtain the exact optimal damping characteristics of shock absorber. With the development of numerical analysis theory and computer technology, the simulation analysis can be used to predict the performance of damper which has a certain significance.Taking a certain type of vehicle shock absorber as the research object, this paper has established simulation model of the shock absorber. Analyzing the impact of the structural parameters of damper on dynamic characteristics with the combination of fluid mechanics and solid finite element calculation. Mainly includes the following 5 aspects of the content:(1) Damper’s bench test:A group of damping characteristic curves vary with piston’s speed are acquired by analyzing damper’s dynamic property through experimental method. Therefore the effect of damper’s velocity characteristic on its damping performance is obtained.(2) The 3d simulation model of damper’s flow field is established in order to simulate its dynamic process. Get the valve opening status at different speeds of the shock absorber by using numerical analysis method, and the analysis of shock absorber internal flow pressure and flow rate.(3) In order to obtain the influence of damper normally through hole and piston throttle valve to the damping characteristic, change its size, calculate and analyze its influence. Analysis obtained that:The amplitude of damping force will become larger as the hole’s size is smaller. The hole of the piston throttle valve has influence on the damping force during the stretch stroke, the larger the hole size, the smaller the damping force, and the change of the hole size has little effect on the damping force under high speed.(4) In order to get the valve disc stiffness, the stiffness of the valve plate is calculated by the finite element method, the effect of the number of the valve on the valve disc stiffness are analyzed. Analysis obtained that:When the total thickness of the valve plate is the same, the equivalent stiffness of the valve plate is gradually decreased with the increase of the number of valve plates. The stiffness of the valve is reduced, the opening speed becomes large, the damping force of the damper is reduced. When the valve thickness is the same, the number of valve plates increases, the deformation decreases, the valve disc stiffness increases, the valve opening speed becomes small, the damping force of the shock absorber becomes large.(5) In order to find out the influence of spring and valve’s stiffness on the performance of the damper, the influences of different valve plate and spring stiffness on the damping characteristics and speed characteristics of the damper are calculated under the same speed. Analysis obtained that:The greater the magnitude of the damping force of the valve plate group, the greater the damping force is, the greater the damping force is required. Within a certain range, the opening degree of the valve plate has a linear relationship with the damping force, and the greater the stiffness is, the more obvious the nonlinear characteristics are. The change of spring stiffness has little effect on the amplitude of damping, but the damping force is less affected by the compression process.