1, control the movement of the machine, such as the engine valve spring, control of clutch spring, etc.

2, absorption of vibration and impact energy, such as buffer spring under the car, train carriages, coupling of the vibration-absorbing springs, etc.

3, storage and output energy as power, such as clock spring, spring in the gun etc.

4, used as the load components, such as force-measuring device, the spring spring balance, etc. The ratio of the load and deformation of the spring called spring stiffness, the stiffness, the greater the spring harder.

According to stress nature, spring can be divided into tensile spring, compression spring, torsion spring and bending spring, according to the shape can be divided into the disc spring, circular spring, leaf spring, coil spring, truncated cone vortex coil spring and torsion bar spring, etc. Ordinary cylindrical spring because of its simple manufacture, and can be made into various types according to the load situation, simple structure, is the most widely used.