Seal type of cylinder
Everyone knows that construction machinery cannot be separated from the oil cylinder, and the oil cylinder cannot be separated from the seal. A common seal is a sealing ring, also called an oil seal, which plays a role of insulating oil and preventing oil from overflowing or passing through. What are the types of cylinder seals?
1. Dust ring: The dust ring is installed on the outside of the end cover of the hydraulic cylinder to prevent external contaminants from entering the cylinder. It can be divided into snap-in type and press-in type according to the installation method. The snap-in dust wiper, as the name implies, is snapped into a groove in the inner wall of the end cap for use in less severe environmental conditions. The material of the snap-in dust wiper is usually polyurethane, and there are many variants of the structural form. For example, the H and K cross sections are double-lip structures, but they are invariable. The press-in dust wiper is used under severe and heavy load conditions, and is not stuck in the groove. Instead, the polyurethane material is wrapped with a layer of metal to increase strength and is pressed into the end cap of the hydraulic cylinder. There are also many types of press-in dust wipers, which are also divided into single and double lips.
2. Piston rod seal: also known as U-cup, is the main piston rod seal, installed inside the end cover of the hydraulic cylinder, the role is to prevent hydraulic oil from leaking. The piston rod seal ring is made of polyurethane or nitrile rubber. In some cases, it needs to be used with a support ring (also called a retaining ring). The support ring is used to prevent the seal ring from being deformed under pressure. There are also many variations of piston rod seals.
3. 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 one-piece seal made of polyurethane. Types B and C are two-pieces designed to prevent seal squeeze and allow seals to withstand higher pressures.
4. Guide support ring: The guide support ring is installed on the end cover of the hydraulic cylinder and the piston, and is used to support the piston rod and piston, and guide the piston to perform linear movement to prevent metal-to-metal contact. Materials include plastic, bronze coated with Teflon, etc.
5. End cap sealing ring: It is used to seal the cylinder end cap and the cylinder wall. It is a static seal to prevent hydraulic oil from leaking from the gap between the end cap and the cylinder wall. It usually consists of a nitrile rubber O-ring and a support ring (retaining ring).
6. Piston seal: It is used to isolate the two chambers of the hydraulic cylinder. It is the main seal in the hydraulic cylinder. Usually two-piece, the outer ring is made of Teflon or nylon, and the inner ring is made of nitrile rubber. There are also many variations, including the use of Teflon-coated bronze, among others. On single-acting cylinders, there are also polyurethane U-cups.