Automobile shock absorption
In the suspension system, the elastic element vibrates due to impact. In order to improve the ride comfort of the vehicle, the shock absorber is installed in parallel with the elastic element in the suspension. In order to attenuate the vibration, the shock absorber used in the vehicle suspension system is mostly hydraulic shock absorber. Its working principle is that when the vibration between the frame (or body) and the axle occurs relative movement, the piston in the shock absorber moves up and down, The oil in the shock absorber cavity repeatedly flows from one cavity through different pores into another cavity.
At this time, the friction between the hole wall and the oil [1] and the internal friction between the oil molecules form a damping force on the vibration, so that the vehicle vibration energy is transformed into oil heat energy, which is absorbed and emitted into the atmosphere by the shock absorber. When the oil channel section and other factors remain unchanged, the damping force increases or decreases with the relative motion speed between the frame and the axle (or wheel), and is related to the oil viscosity.
The shock absorber and elastic element undertake the task of reducing impact and vibration. If the damping force is too large, the elasticity of the suspension will deteriorate, and even the connecting parts of the shock absorber will be damaged. Because of the contradiction between the elastic element and the shock absorber.
(1) During the compression stroke (the axle and frame are close to each other), the damping force of the shock absorber is small, so as to give full play to the elastic effect of the elastic element and mitigate the impact. At this time, the elastic element plays a major role.
(2) During the suspension extension stroke (the axle and frame are far away from each other), the damping force of the shock absorber should be large and absorb vibration quickly.
(3) When the relative speed between the axle (or wheel) and the axle is too large, the damper is required to automatically increase the fluid flow to keep the damping force within a certain limit, so as to avoid bearing excessive impact load.
The cylindrical shock absorber is widely used in the automobile suspension system, and it can play the role of shock absorption in both compression and extension stroke. It is called bidirectional shock absorber. There are also new shock absorbers, including inflatable shock absorber and resistance adjustable shock absorber.
