1. Structural form of seals

The structural form of the seal is improperly chosen. Very easy to cause leakage. Usually, the structure of hydraulic seals has a very complex effect on leakage. But under the same working conditions, the leakage of lip-type seals is usually less than that of the self-styled pressure-tight type seals, and lip-type seals are usually the least leakage of YX-type seals.

2. Sealing material

The material selection of seals is very easy to cause leakage. If the sealing material is too soft, then the hydraulic cylinder work, seals extremely easy to squeeze into the seal gap and damage, resulting in leakage of hydraulic oil. If the sealing material is too hard. Even under the action of larger external forces, the deformation of seals is also difficult, it is obvious that the initial contact stress and additional contact stress caused by the sealing surface will be lower, thus aggravating the leakage of hydraulic oil. If the sealing material is incompatible with the hydraulic oil, then the seal will dissolve, soften, dissolve or harden, etc., no longer has the elasticity and loses the seal effect, causes the hydraulic oil leakage.

3. Design and manufacture quality of sealing groove

The size of the sealing groove is unreasonable

If the section size of the sealing groove is too large, the compression deformation produced after the seal is installed is too small. The initial contact stress caused by seals on the sealing surface is low, which is very easy to cause leakage. On the other hand, if the size of the sealing groove is too small, although the compression deformation of the seal is too large, but the friction resistance is larger, the temperature rise is higher, the seals are prone to premature wear and cause leakage.

4. Sealing surface design and manufacturing quality

Sealing gap is unreasonable

If the seal gap is too large, then under the action of pressure liquid, seals extremely easy to squeeze into the seal clearance, in the hydraulic cylinder frequently works under the action extremely easily damage seals and causes the leakage. If the seal gap is too small, then the two relative moving parts of the surface is not enough to form the relative movement of the minimum lubricant film required, resulting in a dry friction or dry friction, speed up the seal of premature wear and other causes of leakage.

When the surface roughness and the shape position accuracy are low, the sealing surface and the sealing parts are frequently contacted. It is very easy to damage the seals and cause leakage.

5. Installation quality of sealing parts

Seals belong to standard parts, with higher dimensional accuracy and shape position accuracy and smooth surface. However, because the Assembly is not careful or brutal assembly easily caused damage and/or produce a larger plastic deformation, etc., easy to weaken its sealing effect, resulting in leakage of hydraulic oil.

6. Working environment of Seals

The higher the relative movement speed of the ① sealing surface, the thicker the oil film thickness formed between the seal and the sealing surface. So the leak is also more serious.

The higher the working pressure of the ② hydraulic oil, the higher the oil film pressure formed between the sealing part and the sealing surface. Obviously the more serious the leak.

The higher the temperature of the ③ hydraulic oil, the smaller the oil film viscosity formed between the sealing parts and the sealing surface, and the leakage is serious.

④ other factors, such as dust flying, air humidity and so easily pollute the hydraulic oil and accelerate the wear and tear of seals and other causes of leakage.

7. The pollutant of the hydraulic cylinder

Dust particles and water droplets will invade the hydraulic transmission system in different ways and from different ways. At the same time, hydraulic pumps and hydraulic valves and other normal wear and tear produced by the debris will also accelerate the pollution of hydraulic oil. Moreover, the hydraulic oil containing solid particulate contaminants is similar to the abrasive of the machined surface of the metal parts, which causes the leakage of the seals to wear prematurely.