If the car frame (or body) is directly installed on the axle (or wheel), the goods and people will feel very uncomfortable due to the uneven road and the impact of the ground. This is because there is no suspension device. Automobile suspension is the general designation of elastic coupling device between frame (or body) and axle (or wheel). Its function is to connect the axle and the frame (or body) elastically, so as to alleviate the impact force on the vehicle during driving. Ensure that the goods are in good condition and the personnel are comfortable; attenuate the vibration introduced by the elastic system, so that the vehicle can maintain a stable posture and improve the handling stability; at the same time, the suspension system undertakes to transfer the vertical reaction force, longitudinal reaction force (traction force and braking force) and lateral reaction force as well as the torque caused by these forces to the frame (or body) to ensure smooth driving of the vehicle; and And when the wheel relative to the frame jump, especially in steering, the wheel trajectory must meet certain requirements, so the suspension also plays a guiding role in making the wheel jump relative to the body according to a certain track.

Whether the suspension structure and performance parameters are reasonable or not has a great influence on vehicle ride comfort, handling stability and comfort. It can be seen that the suspension system is one of the important assemblies in modern automobiles.