The first major category of cylinder seals: compression seals
Compress the sealing ring When the sealing ring is placed into the sealing groove, there will be a certain amount of pre-compression, and the leakage path will be blocked by the contact surface pressure on the sealing surface, such as an O-shaped and square sealing rings, etc.
The second largest category of cylinder seals: air pressure seals
Pneumatic sealing rings rely on air pressure to press the lip of the sealing ring against the sealing surface to ensure sealing, such as lip seals. See the figure below for the sealing principle and characteristics of the sealing ring. Commonly used sealing materials are nitrile rubber and polyurethane.
Application range of different cylinder seals:
① The seal connecting the cylinder head and the cylinder barrel generally uses an O-ring seal installed in the groove of the cylinder head and the cylinder barrel;sometimes a rubber equal washer is also used to place it in the groove. Connect to the seam to form a flat seal.
② Piston sealing There are two places in the piston that need to be sealed. One is the dynamic seal between the piston and the cylinder. In addition to using O-rings and lip seals , W-shaped seals are also used. It is a sealing structure in which the piston and rubber are vulcanized into one body. The W-shaped seal is a two-way seal with small axial size. The other place is the static seal at the connection between the piston and the piston rod, generally using an O-ring.
③ To seal the piston rod, place a lip seal ring and a dust-proof seal ring, or a dust-proof combined seal ring in the groove of the cylinder head to ensure that the piston rod reciprocates Sealed and dustproof.
④ There are two methods for sealing the buffer plunger: one is to place a lip seal ring in the groove of the buffer plunger, and the other is to install a lip seal on the cylinder head Press up and insert the special sealing ring for cylinder buffer. It is composed of a lip seal vulcanized on a round steel cover. The buffering performance of this special buffer sealing ring is better than the former. The floating buffer seal structure that has appeared in recent years has a lip seal ring floating on the cylinder head. When the buffer plunger enters the buffer, the floating lip seal can move a short distance with the buffer plunger. The use of this floating seal structure can reduce the concentricity requirements for the processing and installation of cylinder parts and ensure the buffer sealing performance.
Cylinder sealing faults and troubleshooting
External leakage: The working air leaks from the inside of the cylinder block to the outside. The air leakage that occurs is called external leakage.
1. The sealing ring is worn and should be replaced in time;
2. The piston rod is eccentric;reinstall it so that the piston rod is not affected by the eccentric load;
3. The piston rod is damaged;replace the piston rod;
4. There are impurities in the mating surface of the piston rod and sealing bushing;remove the impurities and install a dust cover;
Internal leakage: occurs inThe leakage between the front chamber and the rear chamber inside the cylinder body is called internal leakage.
1. The piston sealing ring is damaged;replace the piston sealing ring;
2. Poor lubrication;check the lubrication device and lubricating oil;
3. The piston is stuck;reinstall it so that the piston rod is not affected by eccentric load;
4. The piston mating surface is defective, and impurities are squeezed into the sealing surface. If the defect is serious, replace the parts and remove impurities.
WhatsApp: +8615857777578