The car suspension consists of three parts: elastic element, shock absorber and force-transmitting device. These three parts act as buffering, damping and force transmission.
Coil spring: It is the most used spring in modern cars. The utility model has the advantages of strong shock absorption and good riding comfort; the disadvantage is that the length is large, the space is occupied, and the contact surface of the installation position is also large, so that the arrangement of the suspension system is difficult to be very compact. Since the coil spring itself cannot withstand the lateral force, a complicated combination mechanism such as a four-link coil spring has to be employed in the independent suspension. For the sake of ride comfort, it is desirable that the spring can be softer for ground impacts with high frequency and small amplitude, and when the impact force is large, it can exhibit greater rigidity and reduce the impact stroke, so the spring is needed. There are two or even more than two stiffnesses at the same time. Springs with different wire diameters or springs with unequal pitches can be used, and their stiffness increases with increasing load.
Leaf spring: It is mostly used in vans and trucks. It is composed of several elongated spring pieces with different lengths. Compared with the coil spring, the structure is simple, the cost is low, and it can be compactly assembled on the bottom of the vehicle body, and friction is generated between the pieces during operation, so that it has a damping effect. However, if severe dry friction occurs, it will affect the ability to absorb shock. Modern cars that value ride comfort are rarely used.
Torsion bar spring: A long rod made of spring steel with torsion rigidity. One end is fixed to the vehicle body, and one end is connected with the upper arm of the suspension. When the wheel moves up and down, the torsion bar is twisted and deformed to function as a spring.
Gas spring: replaces the metal spring with the compressibility of the gas. Its greatest advantage is its variable stiffness, which gradually increases stiffness as the gas continues to compress, and this increase is a continuous gradual process, unlike metal springs that are graded. Another advantage is that it is adjustable, that is, the stiffness of the spring and the height of the body can be actively adjusted.