In the suspension system, the elastic element is impacted and vibrates. In order to improve the ride comfort of the car, a shock absorber connected in parallel with the elastic element is installed in the suspension system. In order to attenuate vibration, most of the shock absorbers used in automobile suspension system are hydraulic shock absorbers. Its working principle is that when the frame (or car body) and the axle move relatively due to vibration, the piston in the shock absorber moves up and down, and the oil in the shock absorber cavity repeatedly flows from one cavity to another through different small holes. At this time, the friction between the hole wall and the engine oil and the internal friction between the engine oil molecules form a damping force on the vibration, so that the vibration energy of the automobile is converted into engine oil heat energy, which is absorbed by the shock absorber and radiated to the atmosphere. When the oil channel section and other factors are constant, the damping force increases or decreases with the relative movement speed of the frame and axle (or wheel), and it is related to the viscosity of oil.
Shock absorbers and elastic elements undertake the task of buffering impact and reducing vibration. If the damping force is too large, the elasticity of the suspension will deteriorate, and even the connecting piece of the shock absorber will be damaged. Because of the contradiction between elastic element and shock absorber.
test method
1. Drive on a road with poor road conditions 10km, then stop and touch the housing of the shock absorber with your hands. If it is not hot enough, you can add appropriate lubricating oil when explaining the shock absorber and then test it. If the shell is hot, it is the lack of oil inside the shock absorber, you should add enough oil; Otherwise, the shock absorber is invalid.
2. Press the bumper hard and release it. If the car jumps 2~3 times, the shock absorber works well.
3. When the car is driving slowly and braking urgently, if the car vibrates violently, there is something wrong with the shock absorber.
4. Remove the shock absorber and erect it, clamp the lower connecting ring on a vise, and press the shock absorber rod hard for several times. There should be steady resistance at this time. If the resistance is unstable or there is no resistance, it may be that the shock absorber is short of oil or the valve parts are damaged, and the parts should be repaired or replaced.