The V-ring seal has a V-shaped cross section and is also a lip seal. The V-shaped combination seal ring is composed of a support ring, a V-shaped seal ring and a pressure ring. The standard angle of the V-ring is 90°, and 60° for special seals. The support ring is an important part to support the V-ring. The section is thick and strong, the size is accurate, the concave angle and the V-ring seal are the same (90°) or slightly larger, which makes the V-ring stable. . The function of the pressure ring is to create an initial compression amount for the V-ring, so that the V-ring is in full contact with the surface to be sealed, and the compression of the V-ring can be adjusted. In the free state, the outer diameter of the sealing lip of the V-ring seal is larger than the inner diameter of the packing cavity, and the inner diameter of the sealing lip is smaller than the outer diameter of the piston rod. In this way, there will be a certain amount of deformation after installation. Due to the action of the support ring, this deformation occurs only at the tip end of the sealing lip and generates pressure at the contact portion thereof, and the sealing lip can seal a certain internal pressure even if no pressing force is applied. Because the deformation of the sealing lip has self-sealing effect, when the working pressure of the sealing medium increases, the sealing lip tip changes the contact shape and increases the contact stress, and the sealing lip and the sealed surface are more closely attached to achieve the sealing effect, and the medium pressure rises. The high contact stress increases accordingly.

When the working pressure of the medium is high, several V-rings can be used in combination, and the pressing force is applied to the V-ring seal through the pressure ring. Several V-ring seals are combined into one piece, and the pressing force is combined. Can be adjusted according to the medium pressure. Even if the leakage medium passes through the first V-ring seal, the pressure will be greatly reduced. By the sealing lip of the second V-ring seal, the pressure will drop once, and the internal pressure will be lost. Finally, The leak was blocked. The compressed 3~4 ring V-ring seals the internal pressure of 60MPa or higher.

The V-ring can only work in one direction. When it is used as a double-acting piston seal, two sets of V-rings arranged symmetrically must be used. At this time, the size of the piston is greatly lengthened and the frictional resistance is also increased.

The material of the V-ring seal is most commonly used for nitrile rubber and neoprene. Natural rubber is used for sealing water and air. Butyl rubber is used for non-combustible hydraulic oil and phosphate ester hydraulic oil. Chlorine rubber is used in a variety of chemicals and high temperatures. When abrasion resistance is required, urethane rubber is used.

Clamped fabric rubber is also a commonly used material for V-rings. It is characterized by increasing the rigidity and strength of the sealing ring, preventing the occurrence of rubber extrusion and gap biting, making it suitable for high pressure. At the same time, during the wear process, the rubber is worn before the fabric, and when the contact pressure is large, the wear of the entire sealing surface tends to be uniform, and the friction does not change significantly. However, the lip of the rubber seal of the fabric is easy to scrape off the oil film on the sliding surface, so the lubricity is relatively poor. The pressure ring and the support ring are generally pressed with a harder tape which is sometimes pressed with a hard plastic.