According to the nature of the force, the compressed spring can be divided into tension springs, compression springs, torsion springs and bending springs; according to the shape can be divided into disc springs, ring springs, plate springs, coil springs, cut cone scroll spring and torsion spring The Ordinary cylindrical spring as a result of simple manufacturing, and according to the load made of various types, simple structure, so the most widely used. Spring manufacturing materials should generally have a high elastic limit, fatigue limit, impact toughness and good heat treatment performance, commonly used carbon spring steel, alloy spring steel, stainless steel spring and copper alloy, nickel alloy and rubber Wait. Spring manufacturing methods are cold roll and hot roll method. The diameter of the spring wire is less than 8 mm in general with a cold roll method, greater than 8 mm using a hot roll method. Some springs in the made after the pressure or shot peening, can improve the carrying capacity of the spring.