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2022

Advantages of large size seal

The self-sealing compression seal specifications commonly used in large-size seals include O-rings, square seals, etc. The temperature is suitable for various sealing occasions. Large-size seals have simple structure, easy design and operation, and low sealing material cost. It has many advantages and is the best choice for ordinary customers who do not require high sealing materials. O-rings are dynamic and static sealing components used in many hydraulic transmission systems. It is installed in the seal groove and is deformed by the radial compression of the friction of the mechanical movement, which generates contact stress on the higher surface of the seal, forming a leakage condition to prevent unpressurized liquid.

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　　Large size sealCommonly used in the self-sealing compression seal specifications are O-ring, square seal, the temperature is suitable for a variety of sealing occasions. Large-size seals have simple structure, easy design and operation, and low sealing material cost. It has many advantages and is the best choice for ordinary customers who do not require high sealing materials. O-rings are dynamic and static sealing components used in many hydraulic transmission systems. It is installed in the seal groove and is deformed by the radial compression of the friction of the mechanical movement, which generates contact stress on the higher surface of the seal, forming a leakage condition to prevent unpressurized liquid.

During the working process of the hydraulic cylinder, the internal liquid extrusion process further deforms the sealing ring, and a large pressure on the sealing surface depends on the liquid. Strictly speaking, it should be pressure. The increased large-gauge seal adds additional contact stress and, together with the initial contact stress, prevents leakage of the pressurized liquid. However, when the working pressure is greater than 10Mpa, in order to avoid the synthetic rubber self-sealing compression type large-size seal being squeezed into the sealing gap, the hydraulic cylinder will be cut off in the reciprocating motion and cause leakage. Install the resin retaining ring.

(1)O-ring overview and sealing principle

O-ring seal is referred to as O-ring, which is a rubber ring with a circular cross section. O-rings are the most widely used seals in hydraulic and pneumatic systems. O-rings have good sealing performance and can be used for static and dynamic seals; they can not only be used alone, but also are the basic components of many combined sealing devices. Its use range is very wide, if the material is selected properly, it can meet the requirements of various media and various sports conditions.

O-rings are squeeze seals. The basic working principle of the squeeze seal is to rely on the elastic deformation of the seal to generate a contact pressure on the contact surface of the seal. If the contact pressure is greater than the internal pressure of the sealed medium, it will not occur. leakage and vice versa.

(2) Compression ratio and current stretching

An O-ring is a typical squeeze seal. The compression ratio and elongation of the O-ring section diameter are the main contents of the seal design, which are of great significance to the sealing performance and service life. The good sealing effect of the O-ring largely depends on the correct matching of the size of the O-ring with the size of the groove to form a reasonable compression and tension of the sealing ring.

From the above factors is not difficult to find, they are contradictory. A larger compression ratio can obtain a larger contact pressure, but an excessively high compression ratio will undoubtedly increase sliding friction and permanent deformation. If the compression ratio is too small, it may cause leakage due to the coaxiality error of the sealing groove and the O-ring error does not meet the requirements, resulting in the disappearance of part of the compression. Therefore, when choosing the compression ratio of the O-ring, various factors must be weighed. Generally, the compression ratio of the static seal is greater than that of the dynamic seal, but the extreme value should be less than 25%, otherwise the compressive stress will obviously relax, resulting in excessive permanent deformation, especially under high temperature conditions.

Since the synthetic rubber ring has a large compression deformation in the working range, it must maintain its anti-static friction. This is why large-size seals rarely operate alone, because static friction resistance can produce undesirable conditions, such as low-pressure creep in hydraulic systems or operating difficulties.

Key words:

Large size seal