Automobile suspension is an elastic device connecting frame and axle in automobile. It is generally composed of elastic elements, guiding mechanism, shock absorber and other components. Its main task is to mitigate the impact from uneven road surface to the frame, so as to improve the comfort of riding. Automobile suspension consists of three parts: elastic element, shock absorber and force transmission device, which play the role of buffer, shock absorption and force transmission respectively. Coil spring: it is the most widely used spring in modern automobile. It has strong shock absorption ability and good riding comfort. Its disadvantages are large length, large space occupation and large contact surface of installation position, which makes the layout of suspension system difficult to be very compact. Because the coil spring itself can't bear the transverse force, it is necessary to adopt the complex combination mechanism such as four-bar coil spring in the independent suspension. Leaf spring: it is mainly used in van and truck. It is composed of several long and thin springs with different lengths. Compared with coil spring, it has simple structure and low cost. It can be assembled in the bottom of the car body compactly. When it works, there is friction between the plates, so it has attenuation effect. But if there is serious dry friction, it will affect the ability to absorb impact. Modern cars that emphasize ride comfort are rarely used. Torsion bar spring: a long bar made of spring steel with torsion rigidity. One end is fixed on the body, the other end is connected with the upper arm of the suspension. When the wheel moves up and down, the torsion bar deforms and acts as a spring.
Independent suspension, the suspension structure commonly used in front wheels of cars. The left and right wheels do not interfere with each other, and the independent fulcrum moves up, down, left and right, which makes the car comfortable.
Non independent suspension, the structure commonly used by some low-end cars and legal cars, the left and right wheels are connected by a single axle, and when one side of the wheel floats with the road conditions, the other side of the wheel will move in the opposite direction, which is certainly not better than independent suspension, but it saves costs, and the French people always think that the performance of the non independent suspension vehicles they teach does not need to be independently suspended.
Semi independent suspension, on the basis of non independent suspension plus balance bar to improve the inherent shortcomings of non independent suspension, horizontal direction plays a stable role.