In the machine tools, ships, automobiles, aerospace equipment, metallurgical machinery, chemical machinery, engineering machinery, construction machinery, mining machinery, petroleum machinery, plastic machinery, agricultural machinery, and various types of instruments, a large number of types of seals are applied. element. O-rings are mainly used for static and reciprocating seals. For rotary motion seals, only for low speed rotary seals. O-rings are generally mounted in a groove with a rectangular cross section on the outer or inner circle to seal. O-ring seals still have good sealing and shock absorption in oil, acid, alkali, grinding and chemical corrosion. Therefore, O-rings are the most widely used seals in hydraulic and pneumatic transmission systems.