What Are the Categories of Shock Absorbers?

Types of shock absorbers from the material point of view

First, from the perspective of materials, shock absorbers can be divided into two types: hydraulic and pneumatic, as well as a type of variable damping shock absorber.

Hydraulic shock absorber

The hydraulic shock absorber is widely used in automobile suspension systems. The principle is that when the frame and the axle of the vehicle move reciprocally and the piston moves back and forth in the shock absorber cylinder, the oil in the shock absorber shell repeatedly flows from the inner cavity through some narrow pores to another inner cavity. At this time, the friction between the liquid and the inner wall and the internal friction of the liquid molecules form a damping force against vibration.

Pneumatic shock absorber

The pneumatic shock absorber is a new type of shock absorber developed since the 1960s. Its structural feature is that a floating piston is installed in the lower part of the cylinder, and a sealed air chamber filled with high-pressure nitrogen gas is installed in the end of the cylinder where the floating piston is located. A large cross-sectional O-ring seal is installed on the floating piston to completely separate the oil and gas. The working piston is equipped with a compression valve and an extension valve that change the channel cross-sectional area according to its motion speed.

Types of shock absorbers from the structural point of view

Second, shock absorbers can be divided into single-tube and twin-tube structures. They can also be further divided into single-tube air pressure shock absorbers, twin-tube oil pressure shock absorbers, and twin-tube oil and gas shock absorbers.

Twin-tube shock absorber

The twin-tube shock absorber has an internal and an external cylinder, and the piston moves in the internal cylinder. Due to the movement of the piston rod in and out, the volume of oil in the internal cylinder increases and decreases, so it needs to be exchanged with the external cylinder to maintain the balance of oil in the internal cylinder. Therefore, there are four valves in the twin-tube shock absorber, which are the two throttle valves on the piston and the flow valve and compensation valve that complete the exchange function between the internal and external cylinders.

Single-tube shock absorber

Compared with the twin-tube shock absorber, the single-tube shock absorber has a simpler structure and reduces a set of valve systems. It has a floating piston installed in the lower part of the cylinder (the so-called floating means that there is no piston rod to control its movement), and a sealed air chamber filled with high-pressure nitrogen gas is formed under the floating piston. The height of the liquid surface caused by the piston rod entering and exiting the oil is automatically adapted by the floating of the floating piston.

In addition to the above two types of shock absorbers, there are also adjustable damping shock absorbers that can change the size of the throttle orifice by external operation. Recently, electronic control shock absorbers have become standard equipment for cars. The damping adjustment mechanism on the shock absorber works automatically through the sensor detecting the driving status and the computer calculating the optimal damping force.