Do You Know Which O-rings Are Commonly Used?

Common sealing rings can be divided into O-ring seals and lip seals according to their cross-sectional shape, and lip seals can be further divided into Y-shaped, V-shaped sealing rings, etc.
1, O-ring seal
O-ring, also known as O-ring, has a circular cross-section. O-ring seals are generally made of oil resistant rubber (nitrile rubber, polyurethane rubber, etc.) and have good compatibility with commonly used petroleum based hydraulic oils. It is mainly used for static and sliding seals, and is less commonly used in rotary seals. When used for sliding seals. The usage speed of O-ring is required to be between 0.005M/s and 0.3m/s.
The inner, outer, and end of the O-ring seal can all provide sealing function. The sealing principle is. After the O-ring is installed in the sealing groove, its cross-section is compressed and deformed. When there is no liquid pressure, the elastic contact surface of the O-ring generates pre contact pressure to achieve initial sealing.
2, Y-shaped sealing ring
The overall shape of the Y-shaped sealing ring is circular, with a Y-shaped cross-section. It belongs to the category of lip seals and is generally made of oil resistant nitrile rubber. It is a sealing ring with good sealing, stability, and pressure resistance, low friction resistance, and long service life, so it is widely used. Y-shaped sealing rings are mainly used for sealing reciprocating motion devices. According to the different aspect ratios of the cross-section, Y-shaped rings can be divided into two forms: wide cross-section and narrow cross-section. Figure Fi-4 shows a wide cross-section Y-shaped sealing ring.
The sealing effect of a Y-shaped ring relies on the tight contact between its lip and mating surface, and generates a large contact pressure under the action of pressure oil to achieve the sealing purpose. When the hydraulic pressure increases The lip edge and coupling surface are more tightly attached, with higher contact pressure, and the Y-shaped ring has a certain degree of automatic compensation ability after wear, so it has good sealing performance.
3, V-shaped sealing ring
The V-shaped ring is made by pressing multiple layers of adhesive coated fabric Its cross-section is V-shaped, as shown in Figures 6-6. The V-shaped sealing device is composed of a pressure ring, a V-shaped ring, and a support ring, and must be used as a complete set when needed. It is suitable for working under conditions where the working pressure is not greater than 50MPa and the temperature is -40 ℃ -80 ℃. When the working pressure is higher than 10MPa, the number of V-shaped sealing rings can be increased, but not more than 6, to improve the sealing effect. During installation, the opening of the V-shaped ring should face the side with higher pressure.
4, Oil seal
Oil seal usually refers to the sealing of lubricating oil, used on rotating shafts to seal oil internally and prevent dust externally. Oil seals are divided into skeleton free oil seals and skeleton sealed oil seals that are encapsulated on the shaft There should be a certain amount of interference. The lip of the oil seal exerts a certain radial pressure on the shaft, forming a stable oil film. The working temperature of oil seals is generally 20 ℃ to 40 ℃ higher than the working medium temperature, so rubber and acrylic vinegar rubber are generally used. The working pressure of the oil seal cannot exceed 0.05MPa. When installing the oil seal, make sure that the lip is facing this medium.