In the suspension system, the elastic element is shocked to produce vibration. In order to improve the smoothness of the car, a shock absorber is installed in parallel with the elastic element in the suspension to attenuate the vibration. The shock absorber used in the automobile suspension system is mostly hydraulic shock absorber. The working principle of the shock absorber is that when relative movement occurs between the frame (or body) and the axle, the piston in the shock absorber moves up and down, and the oil in the shock absorber cavity repeatedly passes through different The pore flows into another cavity. At this time, the friction between the hole wall and the oil and the internal friction between the oil molecules form a damping force on the vibration, so that the vehicle vibration energy is converted into oil heat, which is then absorbed by the shock absorber and emitted into the atmosphere. When the oil channel cross-section and other factors remain unchanged, the damping force increases or decreases with the relative movement speed between the frame and the axle (or wheel), and is related to the oil viscosity.
The shock absorber and the elastic element undertake the task of buffering and damping shock. Excessive damping force will deteriorate the elasticity of the suspension and even damage the shock absorber connector. Therefore, the contradiction between the elastic element and the shock absorber must be adjusted.
(1) In the compression stroke (the axle and the frame are close to each other), the damping force of the shock absorber is small, in order to give full play to the elastic effect of the elastic element and alleviate the impact. At this time, the elastic element plays a major role.
(2) During the extension stroke of the suspension (the axle and the frame are far away from each other), the damping force of the shock absorber should be large and the shock can be absorbed quickly.
(3) When the relative speed between the axle (or wheel) and the axle is too large, the shock absorber is required to automatically increase the fluid flow, so that the damping force is always kept within a certain limit to avoid excessive impact Load.
In the automobile suspension system, the barrel type shock absorber is widely used, and it can play the role of damping in both compression and extension strokes. It is called a two-way-acting shock absorber. There is also a new type of shock absorber, which includes an inflatable shock absorber. Shock absorber and adjustable resistance shock absorber.