1. Automotive Shock Absorber
Types of Shock Absorber
To speed up the car’s frame and body vibration attenuation to make the driving more
comfortable, most cars are equipped with shock absorbers in the internal suspension
system.
Shock absorbers can be divided into 2 categories, hydraulic and pneumatic, with the
difference in damping materials. And there are shock absorbers that have variable
damping.
Hydraulic pressure shock absorber
Widely used in automobile suspension system is the hydraulic shock absorber. The
principle is that when the frame and axle keep a reciprocating relative motion while the
piston is reciprocating in the shock absorber cylinder, oil in the shock absorber will repeat
flowing from the lumen to another cavity through some narrow pores. In this way, friction
between the liquid and inner wall, as well as friction among liquid molecules will form a
damping force to the vibration.
Pneumatic shock absorber
This is a new type of shock absorbers ever since the 1960s. The structure is
characterized in a floating piston in the lower portion of the cylinder, and the
high-pressure nitrogen in a sealed chamber formed by the floating piston and
one end of the cylinder. The floating piston is equipped with an O-shaped
sealed ring of a large cross section, which separate oil and gas completely.
The working piston has a compression valve and a rebound valve, which can
change the channel’s cross-sectional area according to the velocity of
movement.
When the wheels are moving up and down, the piston will reciprocate in the
oil, and this forms a pressure difference between the upper and lower
chamber of the working piston, so the pressure oil could push away the
compression valve and rebound valve, then flow back and forth. As the valve

2. generates a large damping force to the pressure oil, the vibration is therefore
damped.
Resistance adjustable shock absorber
Cars with a resistance adjustable shock absorber has the suspension
generally equipped with air spring that is stiffness variable. The principle is
that when the pressure of air spring is increased, pressure in the damper
chamber also rises, thus changing the throttling aperture of oil, so as to
achieve the purpose of changing the damping stiffness.