V-ring sealing meaning:
V-shaped ring section is V-shaped, also a labial ring.
The V-shaped sealing device is composed of three parts: support ring, sealing ring and pressure ring. The V-ring has a standard angle of 90 and 60 is used for special occasions. The supporting ring is an important part of supporting the V-shaped sealing ring, its section is thick and strong, accurate in size, concave angle is the same as the V-shaped sealing ring (90) or slightly larger, so that the sealing ring is stable. The function of the pressure ring is to cause an initial compression of the V-shaped ring, so that it has full contact with the sealed surface, and can adjust the compression of the V-shaped ring.
In the free state, the outer diameter of the V-shaped ring lip is greater than the inner diameter of the packing cavity, and the inner diameter of the lip is less than the outer diameter of the piston rod. In this way, there will be a certain deformation after the assembly. Due to the action of the support ring, this deformation occurs only at the tip of the lip and creates pressure at the site of its contact, allowing the lip to seal a certain internal pressure even without applying a compression force. Because the lip has the effect of "self-sealing", when the working pressure of the medium increases, the lip tip changes the contact shape and increases the contact stress, the lip and the sealed surface fit more closely to achieve the sealing effect, and the medium pressure increases the contact stress accordingly.  The main feature of V-rings compared to other labral seals is:
1)However, the sealing performance increases with the number of overlaps, it should be noted that this relationship is not straight; while the friction resistance also increases；
2)It has a strong ability to follow the eccentric load and eccentric movement of the piston or the piston rod, and the leakage prevention effect is very good；
3)If the leakage results from sealing ring deformation or wear, it can be adjusted by its pressing mechanism and pressed again, so it can be used for a long time, with reliable sealing and long life；
4)It can be cut and assembly, installation and maintenance, suitable for difficult to replace the sealing ring；
5)It can be used for low pressure (5MPa) and low speed (3m / min) rotation；
6)No extrusion measures is required under high pressure；
7)Frictional resistance, difficult to adjust, the installation space is large；
Scope for V-ring seals：
The maximum working pressure of V-ring is> 60MPa; applicable for working temperature is-30~80℃; working speed range: nitrile rubber V-ring is 0.02~0.3m/s; and laminated rubber V-ring is 0.005~0.5m/s. Can be used in various forms of high pressure hydraulic equipment, hydraulic machinery reciprocating motion piston and piston rod sealing.
Common materials for V-shaped seals：
V-shaped materials are most commonly used in nitrile rubber and neoprene. Natural rubber is used for sealing water and air, and butyl rubber is used for non-combustible hydraulic oil and phosphate-ester hydraulic oil. Chlorine rubber is used for various chemicals and high temperatures. When wear resistance is required, use polyurethane rubber. Clip fabric rubber is also a commonly used material for V-ring, which is characterized by increasing the stiffness and strength of the sealing ring, to prevent the occurrence of rubber extrusion, gap bite phenomenon, so that it is suitable for high pressure. At the same time, in the process of wear, rubber produces wear before the fabric, when the contact part of the large pressure expands, so that the wear of the whole sealing surface tends to be uniform, but the friction does not change significantly. However, the lip of the clip fabric rubber sealing ring is easy to scrape off the oil film on the sliding surface, so the lubricity is relatively poor. Pressure ring and support ring generally have a harder tape pressing, support ring sometimes also use hard plastic suppression.