Classification of hydraulic seals
Dec 07, 2022
The hydraulic seals commonly used in hydraulic cylinders are mainly divided into O-shaped seals, lip seals and combination seals.
One, O-shaped seal; cross-sectional "O" type, simple shape, material is rubber, wear resistance is not as good as polyurethane, so in the hydraulic system is mainly used for static sealing.
Second, lip-shaped seals; U-shaped seal: U-shaped seal sealing performance is better, but used alone is easy to roll over, its frictional resistance and increase with the increase in working pressure. Therefore, this type of hydraulic seal is only suitable for hydraulic cylinders with low working pressure or low speed.
V-shaped seal ring: V-shaped seal ring shall be used with the support ring and pressure ring, V-shaped seal ring sealing performance is better, according to the size of the working pressure to determine the number of seals used, through the pressure ring can be adjusted to compensate for the wear of the seal ring, the disadvantage is that the structure is complex, its frictional resistance is large. Therefore, this type of V-shaped seal is only suitable for hydraulic cylinders with low movement speed and high working pressure.
YX-shaped seal: YX-shaped seal is the cross-sectional width and its height ratio is greater than 2, and based on the requirements of the use of stability, YX-shaped seal work lip shorter than the non-working lip, thus divided into hole with YX-shaped seal and shaft with YX-shaped seal, YX-shaped seal will not roll over when used, so YX-shaped seal this type of hydraulic seals suitable for high-pressure, high-speed hydraulic cylinder selection.
Three, combination seals
Lace-shaped ring: Lace-shaped ring is composed of synthetic rubber O-ring and cloth rubber Y-shaped seal superimposed, relying on its own deformation to produce a high initial contact stress on the sealing surface to prevent the leakage of non-pressure liquid. When the hydraulic cylinder works, the pressure oil makes the elastic deformation of the O-ring, always squeeze and hold open the sealing lip of the Y-ring, so that it is close to the sealing surface, and together with the initial contact stress to prevent the leakage of pressure oil.
Gyld ring: Gyld ring is composed of O-rubber seal and filled with PTFE square seal superimposed, it can be divided into hole Gyld ring and shaft Gyld ring, but its sealing mechanism is the same, according to its own deformation of the sealing surface to produce a high initial contact stress, to prevent the leakage of non-pressure fluid. When the hydraulic cylinder is working, the pressure oil makes the elastic deformation of O-ring squeeze the square seal, which makes it tight to the sealing surface, and together with the initial contact stress, stops the leakage of pressure oil.
Step Seal: The structure of Step Seal is similar to that of Gyld Ring, which is also composed of O-shaped rubber seal and special shaped rectangular or trapezoidal seal filled with PTFE, and can be divided into Step Seal for hole and Step Seal for shaft. The common feature of Step seal and Gyld ring is filled with PTFE material, low friction, no crawling and long life.
