In the suspension system, vibration is generated due to the impact of the elastic member. In order to improve the ride comfort of the vehicle, a shock absorber is installed in parallel with the elastic member in the suspension, so as to attenuate the vibration, the shock absorber in the automobile suspension system is mostly hydraulic shock absorption. The working principle is that when the frame (or the body) and the axle vibrate and move relative to each other, the piston in the shock absorber moves up and down, and the oil in the shock absorber chamber repeatedly passes through a different cavity. The pores flow into the other cavity.
At this time, the friction between the wall of the hole and the oil and the internal friction between the oil molecules form a damping force for the vibration, so that the vibration energy of the automobile is converted into the thermal energy of the oil, and then absorbed by the shock absorber to the atmosphere. When the oil passage section and other factors are constant, the damping force increases or decreases with the relative movement speed between the frame and the axle (or wheel) and is related to the viscosity of the oil.