Post: what is shock absorber in car

Shock absorbers are vulnerable parts during the use of cars, which quickly attenuate the vibration of the frame and body and improve the smoothness and comfort of the car’s driving. Most car suspension systems are basically equipped with shock absorbers. Whether the shock absorbers work well will affect the smoothness of the car’s driving and the service life of other parts. So how much do you know about the shock absorbers on the car? Next, let’s follow the car series of this site to learn more about the sound of shock absorbers and briefly introduce the car shock absorbers.
Shock absorbers are fragile accessories during the use of cars. The working state of the shock absorber will affect the driving stability of the car and the life of other parts at the same time, so the shock absorber should always be in good working condition.
Shock absorbers are the key to suppressing the impact when the spring bounces after absorbing earthquakes and road impacts. Although the shock-absorbing spring can filter the vibration of the road when passing through uneven roads, the spring itself can also reciprocate, and the shock absorber is used to suppress the spring bounce. If the shock absorber is too soft, the car body will jump up and down. If the shock absorber is too hard, it will bring too much resistance and hinder the normal operation of the spring. In the process of modifying the suspension system, the hard shock absorber needs to be matched with the hard spring, and the hardness of the spring is closely related to the weight of the vehicle, so heavier vehicles mostly use hard shock absorbers. A device connected to the crankshaft that induces shock to counteract the torsional vibration of the crankshaft (i.e. the phenomenon that the crankshaft is twisted due to the impact of the cylinder ignition).
In the suspension system, the vibration is caused by the impact of the elastic element. In order to improve the driving comfort of the car, the shock absorber is installed in parallel with the elastic element in the suspension system. In order to attenuate the vibration, the automobile suspension system mostly uses hydraulic shock absorbers. Its working principle is that when the vibration between the frame (or body) and the axle moves year by year, the piston in the shock absorber moves up and down, and the oil in the shock absorber cavity repeatedly enters another cavity through different pores.
At this time, the friction between the pore wall and the oil and the internal friction between the oil molecules develop and change, converting the damping force into vibration, converting the vibration energy of the car into oil heat energy, which is then absorbed by the shock absorber and dissipated into the atmosphere. When factors such as the cross section of the oil channel remain unchanged, the damping force increases or decreases year-on-year with the speed of movement between the frame and the axle (or wheel), and is related to the viscosity of the oil. The shock absorber and the elastic element undertake the tasks of buffering and vibration reduction. If the damping force is too large, the elasticity of the suspension will deteriorate, and even the connector of the shock absorber will be damaged. It is necessary to adjust the contradiction between the elastic element and the shock absorber.
From the perspective of damping materials, there are two types of shock absorbers: hydraulic shock absorbers and pneumatic shock absorbers, and there is also a variable damping shock absorber.
Hydraulic shock absorbers are widely used in automobile suspension systems. The principle is that when the frame and axle reciprocate year by year, when the piston reciprocates in the cylinder of the shock absorber, the oil in the shock absorber housing repeatedly enters another cavity through a narrow hole. At this time, the friction between the liquid and the inner wall and the internal friction of the liquid molecules become the damping force of the secondary vibration through development and change.
Pneumatic shock absorber is a new type of shock absorber developed in the 1960s. Its structural feature is that a floating piston is installed at the bottom of the cylinder, and the closed air chamber formed by the development and change between the floating piston and one end of the cylinder is filled with high-pressure nitrogen. The floating piston is equipped with a large-section O-ring to completely separate the oil and gas. The working piston is equipped with a compression valve and an extension valve, which change the cross-sectional area of ​​the channel with the movement speed of the channel. When the wheel bounces up and down, the working piston of the shock absorber reciprocates in the oil, causing the oil pressure difference between the upper and lower chambers of the working piston, and the pressure oil pushes the compression valve and the extension valve to flow back and forth. Because the valve has a large damping force on the pressure oil, the vibration is attenuated.
The structure of the shock absorber is that the piston rod with a piston is inserted into the cylinder, and the cylinder is filled with oil. There is a throttle hole on the piston, so that the oil in the two parts of the air separated by the piston can complement each other. Viscous oil will generate damping when passing through the throttle hole. The smaller the throttle hole, the greater the damping force, and the greater the viscosity of the oil, the greater the damping force. If the size of the throttle hole remains unchanged, when the shock absorber works at high speed, excessive damping will affect shock absorption. Therefore, a disc-shaped leaf spring valve is provided at the outlet of the orifice. When the pressure increases, the valve is pushed open, the orifice opening becomes larger, and the damping becomes smaller. Due to the bidirectional movement of the piston, the leaf spring valve is basically installed on both sides of the piston, which are called compression valve and tension valve respectively.
According to its structure, the shock absorber includes single cylinder and double cylinder. It can also include: 1. Single cylinder pneumatic shock absorber; 2. Double cylinder oil shock absorber; 3. Double cylinder oil-gas shock absorber.
It means that the shock absorber has an inner cylinder and an outer cylinder, and the piston moves in the inner cylinder. Due to the in-and-out movement of the piston rod, the amount of oil in the inner cylinder increases and contracts accordingly, so it needs to be exchanged with the outer cylinder to keep the oil amount in the inner cylinder balanced. So there are four valves in the double cylinder shock absorber, that is, in addition to the two throttle valves on the piston mentioned above, there are also circulating valves and compensation valves installed between the inner and outer cylinders to complete the exchange.
Compared with the double cylinder shock absorber, the single cylinder shock absorber has a simple structure and shortens a set of valve systems. It is equipped with a floating piston at the bottom of the cylinder (the so-called floating means that there is no piston rod to adjust its movement), and the floating piston forms a closed air chamber filled with high-pressure nitrogen after development and change. The above-mentioned level changes caused by the oil in and out of the piston rod are automatically adapted by the floating of the floating piston. In addition to the two shock absorbers mentioned above, there are also shock absorbers with adjustable resistance. It can change the size of the orifice by external operation. Recently, electronically adjustable shock absorbers are used as standard equipment in automobiles. The driving state is checked by sensors, and the optimal damping force is calculated by computers, so that the damping force adjustment mechanism on the shock absorber works automatically.
The above is an introduction to Bian Xiao’s automobile shock absorbers. Introduction to automobile shock absorbers Most of the automobile suspension systems are basically equipped with shock absorbers, and double-acting cylinder shock absorbers are widely used in automobiles. There are generally two types of shock absorbers, hydraulic shock absorbers and pneumatic shock absorbers, and another type is variable damping shock absorbers. Automobile shock absorbers are vulnerable parts during the use of automobiles, so the shock absorbers should always be kept in good working condition.