Hello everyone, I am the editor. Today I will introduce to you how many types of seals there are on construction machinery? What are they used for? The following content is compiled by the editor, and the relevant content is for reference.

Construction machinery cannot do without oil cylinders, and oil cylinders cannot do without seals. Common seals are seals, also called oil seals, which play the role of isolating oil and prevent oil from overflowing or passing through.

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Common seals used for hydraulic cylinders are the following types: dust rings, piston rod seals, buffer seals, guide support rings, end cover seals and piston seals.

Dust ring

Dust rings are installed on the outside of the hydraulic cylinder end cover to prevent external contaminants from entering the cylinder. According to the installation method, they can be divided into snap-in and press-in types.

Snap-in dust rings are the most common. As the name suggests, the dust ring is stuck in the groove on the inner wall of the end cover and is used in less harsh environmental conditions. The material of the snap-in dust ring is usually polyurethane. There are many variations in the structure, such as the H and K sections are double-lip structures, but the essence remains the same.

Press-in dust rings are used in harsh and heavy-load conditions. They are not stuck in the groove, but the polyurethane material is wrapped with a layer of metal to increase strength and pressed into the hydraulic cylinder end cover. Press-in dust rings also have many forms, and are also divided into single lip and double lip.

Piston rod seals

Piston rod seals, also known as U-cups, are the main piston rod seals. They are installed on the inside of the hydraulic cylinder end cover to prevent hydraulic oil from leaking out. The piston rod seal is made of polyurethane or nitrile rubber. In some cases, it is necessary to use it with a support ring (also called a retaining ring). The support ring is used to prevent the seal from being squeezed and deformed under pressure. There are also many variations of piston rod seals.

Buffer seal

The buffer seal is used as an auxiliary piston rod seal to protect the piston rod when the system pressure suddenly increases. There are three common types of buffer seals. Type A is a single-piece seal made of polyurethane. Types B and C are two-piece, used to prevent seal extrusion, allowing the seal to withstand higher pressure.

Guide support ring

The guide support ring is installed on the end cover and piston of the hydraulic cylinder to support the piston rod and piston, guide the piston to move linearly, and prevent metal-to-metal contact. The materials include plastic, bronze coated with polytetrafluoroethylene, etc.

End cover seal

The end cover seal is used to seal the end cover of the cylinder with the cylinder wall. It is a static seal used to prevent hydraulic oil from leaking from the gap between the end cover and the cylinder wall. It usually consists of a nitrile rubber O-ring and a support ring (retaining ring).

Piston seals

Piston seals are used to separate the two chambers of the hydraulic cylinder and are the main seals in the hydraulic cylinder. They are usually two-piece, with the outer ring made of PTFE or nylon and the inner ring made of nitrile rubber. There are also many variations, including bronze coated with PTFE, etc. On single-acting cylinders, there are also polyurethane U-cups.