The main function of the shell:
1. Control the mechanical movement, such as the engine valve of shrapnel, clutch control of shrapnel, etc.
(2) to absorb vibration and impact energy, such as under the car, train carriages of buffer shrapnel, coupling of vibration absorbing shrapnel, etc.
3. The storage and output energy as power, such as clocks shrapnel, shrapnel in the gun etc.
4. Used for load components, such as force-measuring device, shrapnel shrapnel in the scale etc.
