Automotive leaf spring is the most traditional of the elastic element in the vehicle suspension system, good reliability, simple structure, the manufacturing process is short, low cost structure can greatly simplify the advantages, which been widely used. Automotive leaf spring is generally a combination of strength as a group similar to the spring beam by a number of unequal length alloy spring steel. Suspension system, in addition to acting as a buffer inside out, when it disposed longitudinally in the car, and one end of the frame for a fixed hinge connection, can be passed to take up all to the force and torque, as well as to determine the trajectory of the motion of the wheel from the role of the guide, so there is no need to set the other guide means, another automobile spring is a multi-sheet superposition, when under load deformation, each sheet relative sliding friction, generate a certain resistance to promote body vibration attenuation, and therefore such structures can not install the damper. But the leaf spring unit weight of the energy stored in the lowest, the worst due to the utilization of these materials. Usually, multi-leaf spring ε = 60%, a small leaf spring ε = 75% to 85%. Spend a lot of alloy steel, its weight account for 8-9% of the vehicle weight.