Structural Composition of Cylinder

Cylinder is composed of cylinder barrel, cylinder cover, piston, piston rod and seal kits.

1) Cylinder barrel

The inner diameter of cylinder represents the output force of cylinder. The piston should make smooth reciprocating sliding in the cylinder, and the surface roughness of the inner surface of the cylinder should reach Ra 0.8 um.

The piston of SMC and CM2 cylinders is sealed bidirectionally with a combined sealing ring. The piston is riveted with the piston rod without nuts.

2) Cylinder cover

The cylinder cover is provided with an intake and exhaust port, and some are also provided with a buffer mechanism in the end cap. The cylinder cover of the rod side is provided with a sealing ring and a dust-proof ring to prevent air leakage from the piston rod and dust mixing from the outside into the cylinder. A guide sleeve is arranged on the side cover of the rod to improve the guiding accuracy of the cylinder, bear a small amount of transverse load on the piston rod, reduce the downward bending of the piston rod when it extends, and prolong the service life of the cylinder. The guide sleeve is usually made of sintered oil-bearing alloy and forward inclined copper castings. In the past, malleable cast iron was commonly used for cylinder covers. In order to reduce weight and prevent rust, aluminum alloy die casting was often used, and brass material was used for micro cylinders.

3) Piston

The piston is a pressurized part in the cylinder. In order to prevent the piston left and right cavities from channeling each other, a piston sealing ring is provided. The wear-resistant ring on piston can improve the directivity of cylinder, reduce the wear of piston sealing ring and reduce friction resistance. The wear-resistant ring length is made of polyurethane, polytetrafluoroethylene and cloth synthetic resin. The width of the piston is determined by the size of the sealing ring and the length of the necessary sliding part. The sliding part is too short to cause early wear and stuck. Pistons are usually made of aluminium alloy and cast iron. Pistons of small cylinders are made of brass.

4) Piston rod

Piston rod is the most important force component in cylinder. Usually high carbon steel, hard chromium plated surface, or stainless steel are used to prevent corrosion and improve the wear resistance of sealing rings.

5) Seal kits

The seal of parts in rotating or reciprocating motion is called dynamic seal, and the seal of parts in stationary motion is called static seal.

The connection methods between cylinder barrel and end cap are as follows:

Integral type, riveting type, threaded connection type, flange type and tie rod type.

6) The piston must be lubricated by oil mist in compressed air when the cylinder is working. There are also a small number of non-lubricating cylinders.