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Add.: No.4, New Industrial Road, Shipai Tangwei, shipai town, Dongguan City
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Sealing principle of Y-shaped sealing ring
Release time:
2019-07-24 12:30
Source:
Sealing principle of Y-shaped sealing ring
Y-ring sealRely on its open lip against the sealing mating surface. In the absence of internal pressure, only a small contact pressure is generated due to the deformation of the lip tip. In the case of sealing, every point in contact with the sealing medium has a normal pressure equal to the pressure of the medium, so the bottom of the lip ring will be compressed axially, the lip will be compressed circumferentially, and the contact with the sealing surface will be widened. At the same time, the contact stress increases. When the internal pressure rises again, the distribution form and size of the contact pressure are further changed, and the lip and the sealing surface are more closely matched, so the sealing is better. This is the "self-sealing effect" of the Y-shaped ring ".
Due to this self-sealing effect, a Y-ring can effectively seal the high pressure of 32MPa. The effective sealing pressure of a pressure energized seal is equal to the sum of the pre-pressure and the fluid pressure. The Y-shaped seal ring effectively acts on the seal by the action of the lip, and its pre-pressure can be reduced to a small value, and the higher the fluid pressure, the smaller the effect of the pre-pressure. In high-pressure occasions, the effect of the pre-pressure can be ignored. In this case, it is advantageous to reduce the seal friction, since the seal friction is proportional to the seal contact pressure. Therefore, the friction force of the Y-shaped seal ring is less than that of the extrusion type seal while ensuring the seal.
Y-shaped sealing ring is mainly used for reciprocating sealing, by its working principle, Y-shaped ring installation, the lip to the high pressure side, in order to play a role, so the Y-shaped sealing ring can only play a role in one direction. When the coupling piece moves relative to the working speed, a layer of sealing oil film is formed between the sealing lip and the sliding surface. The existence of the oil film can improve the friction condition of the sealing ring and reduce the wear; the oil film plays a sealing role in the pneumatic seal. In the reciprocating motion of the hydraulic component, the oil film thickness is different when the moving part is extended and retracted, and the accumulation of this oil film thickness difference will cause leakage.

Therefore, when the Y-shaped ring is working normally, a very small amount of leakage occurs, and when the reciprocating speed is large, the amount of leakage is large. This is because the reciprocating speed is large, the number of reciprocating becomes very frequent, and the hydrodynamic effect of the oil film increases the thickness of the oil film, forming a rapid accumulation of the oil film. When the viscosity of the working oil increases, the oil film thickness increases accordingly, and the amount of leakage due to the reciprocating speed also increases. However, because the viscosity of hydraulic oil decreases with the increase of temperature, when the hydraulic equipment starts at low temperature, the leakage at the beginning of the movement is large. As the temperature rises due to various losses during the movement, the leakage will Gradually reduce.
The leakage situation of the piston in the reciprocating formation is different. When the internal pressure is low, the amount of leakage in the extraction stroke increases with the increase of the internal pressure. When the internal pressure is sufficiently large (about more than 7.5MPa), the leakage no longer changes with the internal pressure. When the internal pressure p1 of the Y-ring is low, the frictional force increases as the internal pressure increases. When the internal pressure is sufficiently large, the friction force no longer changes greatly. Such as good lubrication, and even a downward trend. The results of foreign starting friction tests on Y-rings show that starting friction has little to do with parking time, which is the biggest difference from O-rings. This is extremely advantageous for machines with intermittent motion. At the same time, when the internal pressure is low, the starting friction increases with the increase of the internal pressure. When the internal pressure exceeds 5MPa, the starting friction will have nothing to do with the internal pressure. Therefore, for high-pressure intermittent machinery, there will be no problem of excessive starting friction. After the sealing lip is worn, the lip has a certain automatic compensation ability due to the pressure of the medium.
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