Suspension is the general name of all the force-transmitting coupling devices between the frame (or load-bearing body) and the axle (or wheel). The function of suspension is to transmit all kinds of forces acting on wheels and moments generated by road surface to the frame (or load-bearing body), and to absorb and reduce the impact and vibration transmitted to the frame due to wheel jumping caused by uneven road surface during driving. Suspension consists of three parts: elastic element, damping device and guiding mechanism. There are several types of elastic elements, such as leaf spring, spiral spring, torsion bar spring, rubber spring and oil-gas spring. Its function is to bear and transmit vertical load, reduce and restrain the impact caused by uneven road surface, and make the frame and axle elastically connected. The damping device is used to accelerate the attenuation of vibration. The guiding mechanism is used to transmit all kinds of forces except vertical force and the moment formed by it, and ensure that the wheel has a certain movement law relative to the frame (or body). In addition, in cars and passenger cars, an auxiliary elastic element, namely a lateral stabilizer, is installed in the suspension in order to prevent the body from tilting too much when steering. The functions are buffering, damping and guiding respectively. The task of * * * is to transfer various forces and moments between the wheel and the frame. According to whether the wheel movements on both sides of the automobile are interrelated, the automobile suspension can be divided into two categories: dependent suspension and independent suspension. The structural feature of dependent suspension is that the wheels on both sides are mounted on an integral axle, and the wheels and the axle are connected with the frame (or body) through elastic elements. The relative stability of the car body is poor. However, this kind of suspension is simple in structure, convenient to manufacture and widely used in freight cars. The structural feature of the independent suspension is that the wheels on both sides are respectively connected with the frame (or car body) through elastic elements, and the disconnected axle is adopted. If the position of one wheel relative to the frame (or body) changes, the other wheel will not be affected. This kind of suspension is complex in structure, but it has good stability in car body and high-speed driving, and is widely used in cars and passenger cars. ]