The principle of operation of shock absorbers

Shock absorbers are used to suppress the impact of the spring when it recovers after shock absorption and the impact from the road surface. It is widely used in automobiles to accelerate the shock absorption of the frame and body and improve the riding comfort of the car. After passing through uneven roads, although the shock absorber spring can filter the road vibration, the spring itself will also have reciprocating motion, and the shock absorber is used to suppress spring jumping.

Suspension system due to the elastic element in the impact vibration, in order to improve the riding comfort of the car, in the suspension parallel installed elastic element shock absorber, for attenuating the vibration, the shock absorber used in the car suspension system is hydraulic shock absorber, more in its working principle is, when the frame (or body) and the shaft relative movement vibration, the piston moves up and down inside the shock absorber, the oil in the shock absorber cavity repeatedly flows from one chamber to another through different pores. 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 vibration energy of the car is converted into oil heat energy, which is then absorbed by the shock absorber and distributed to the atmosphere. When factors such as the oil passage section remain unchanged, the damping force increases or decreases the relative speed between the frame and the shaft (or wheel), which is related to the viscosity of the oil.

Shock absorbers and elastic elements perform the task of shock absorption and shock absorption. If the damping force is excessive, the suspension elasticity will deteriorate, and even the shock absorber joints will be damaged. Therefore, it is necessary to adjust the contradiction between the elastic element and the shock absorber.

(1) In 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 point, the elastic element plays a major role.

(2) In 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 the shock should 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 liquid flow, so that the damping force is always kept within a certain limit to avoid excessive shock load.

Cylinder shock absorbers are widely used in automobile suspension systems, and a type of shock absorber that can play the role of shock absorber in compression and tensile stroke is called bidirectional action shock absorber, and a new type of shock absorber is adopted, which includes pneumatic shock absorbers and resistance adjustable shock absorbers.

Description of the working principle of the two-way acting cylinder shock absorber: In the compression stroke, it means that the car wheel is close to the body, the shock absorber is compressed, and the piston in the shock absorber moves downward at this time. The volume of the lower cavity of the piston decreases and the oil pressure increases. The oil flows through the flow valve to the chamber above the piston (upper chamber). The upper chamber is occupied by part of the piston rod space, so the volume added by the upper chamber is less than the volume reduced by the lower chamber, and then a part of the oil pushes the compression valve back to the storage cylinder. The fuel saving of these valves creates the damping force that is suspended during compression movement. When the shock absorber extends the stroke, the wheel is equivalent to moving away from the body, and the shock absorber is extended. The piston of the shock absorber moves upwards. The oil pressure in the upper chamber of the piston rises, the flow valve closes, and the oil from the upper chamber pushes the extension valve into the lower chamber. Due to the presence of the piston rod, the amount of oil flowing out of the upper cavity is not enough to fill the increased volume of the lower cavity. The main reason is the vacuum created in the lower cavity. At this time, the oil in the storage cylinder pushes the compensation valve 7 into the lower cavity to replenish. Due to the throttling effect of these valves, the suspension acts as a damping in the extension movement.