Shock absorber piston in the cylinder barrel with the vehicle vibration reciprocating movement of oil within the damper case repeatedly from a cavity flow through the pores of some other cavity narrow, this time, cell wall and the friction between oil internal friction of liquid molecules will form a vibration damping force, the vehicle's vibration energy into heat energy, shell Oil and the shock absorber has been absorbed, and then scattered into the atmosphere. Simply put, that is, the kinetic energy converted into heat.