① Control mechanical movement, such as valve spring in internal combustion engine, control spring in clutch, etc. ② Absorb vibration and impact energy, such as buffer spring under car and train carriage, vibration absorption spring in coupling, etc. ③ Store and output energy as power, such as clocks, springs in guns, etc. ④ It is used as force measuring element, such as the spring in the force measuring device and spring scale.
The ratio of load to deformation of spring is called spring stiffness. The greater the stiffness, the harder the spring. Spring is a kind of elastic element widely used in mechanical and electronic industries. When loaded, the spring can produce large elastic deformation and convert mechanical work or kinetic energy into deformation energy. After unloading, the deformation of spring disappears and returns to its original state, and the deformation energy is converted into mechanical work or kinetic energy.