Research On Valve-controlled Adjustable Damping Shock Absorber And Its Damping Characteristics

The shock absorber is an important part of the automotive suspension system. It can attenuate the shock and vibration transmitted to the vehicle body due to the road bumps, thereby ensuring the vehicle to keep stable, safe and comfortable. The adjustable damping shock absorber has the characteristics of adjustable damping level, and can switch the damping level automatically to meet the requirements of various working conditions. The research on the technology of adjustable damping shock absorber has great practical significance due to it has a wide range of application prospects in the automotive industry. In view of this, this article has conducted thorough research in the following aspects.(1) A kind of valve-controlled adjustable damping shock absorber is designed, and its damping characteristics can be adjusted in 4 damping levels. Three dimensional model and virtual assembly of the shock absorber are completed in Pro/Engineer software. Some key components are designed and the parameters are checked.(2) The differential equations and the analytic solutions of a single elastic valve slice and some elastic valve slices are derived based on the theory of the bending deflection in the elastic mechanics. The influences of the bending deformation of the valve slice are studied, and the results show that: valve open value decreases with the ring radius, valve slice thickness, the valve slice number increases, and valve open value increases with the valve slice radius, valve port radius, valve slice radius ratio, valve slice thickness ratio increases. According to the analytical results, the parameters of the elastic valve slice are selected.(3) When the valve is closed or open, the damping force mathematical model of the compression stroke and rebound stroke under the certain working condition is established based on the theory of fluid mechanics. The relationships between the damping force and the velocity of the piston rod and the size of the throttle orifice are researched. The simulation model is built by using MATLAB/Simulink, and the characteristics of force-displacement and force-velocity during its working process are simulated and analyzed.(4) A performance test bench of electro hydraulic servo is set up, and the prototype of the shock absorber is developed. According to a large number of experiments, the characteristics of force-displacement and force-velocity of the shock absorber under the same damping level, different piston rod speed and the same piston rod speed, different damping level are studied. The experimental results are basically in agreement with the simulation analysis. The damping characteristics change significantly when the damping level is switched. This shows that the designed valve-controlled adjustable damping shock absorber has good performances and can meet the requirements of the application.