The front shock absorber of a car is made up of springs and shock absorbers. Shock absorbers are not used to support the weight of the car, but to suppress the shock of the spring after the rebound and absorb the energy of the road impact. Shock absorbers 500357351 and elastic components bear the task of slow impact and shock absorption, too much damping force, will make the suspension elastic deterioration, and even damage the shock absorber connector. Therefore, it is necessary to adjust the contradiction between elastic components and shock absorbers. In the compression stroke (the bridge and the frame are close to each other), the damping force of the shock absorber is small, so as to give full play to the elastic role of the elastic element and mitigate the impact. At this point, the elastic element plays a major role. In the suspension stretch stroke (the bridge and the frame are far away from each other), the damping force of the shock absorber should be large and rapid shock absorption. When the relative speed between the axle (or wheel) and the axle is too large, the shock absorber is required to increase the liquid flow automatically, so that the damping force is always kept within a certain limit, in order to avoid bearing too much impact load.