Cylinder Structure

The cylinder is composed of a cylinder barrel, an end cover, a piston, a piston rod and a seal, etc. Its internal structure is shown in the figure "SMC Cylinder Schematic Diagram":
1) Cylinder
The inner diameter of the cylinder barrel represents the size of the cylinder output force. The piston should slide back and forth smoothly in the cylinder barrel, and the surface roughness of the inner surface of the cylinder barrel should reach Ra0.8μm.
SMC and CM2 cylinder pistons use a combined sealing ring to achieve bidirectional sealing, and the piston and piston rod are connected by riveting without nuts.
2) End cover
The end cover is provided with an inlet and outlet port, and some are also provided with a buffer mechanism in the end cover. The rod side end cover is provided with a sealing ring and a dust ring to prevent air leakage from the piston rod and prevent external dust from mixing into the cylinder. The rod side end cover is provided with a guide sleeve to improve the guiding accuracy of the cylinder, bear a small amount of lateral load on the piston rod, reduce the amount of downward bending when the piston rod is extended, and extend the service life of the cylinder. The guide sleeve is usually made of sintered oil-containing alloy and forward-leaning copper castings. End caps used to be made of forgeable cast iron. To reduce weight and prevent rust, aluminum alloy die-casting is often used. Brass materials are used for micro cylinders.
3) Piston
The piston is a pressure-bearing part in the cylinder. In order to prevent the left and right chambers of the piston from leaking gas, a piston seal is provided. The wear-resistant ring on the piston can improve the guiding property of the cylinder, reduce the wear of the piston seal, and reduce friction resistance. The wear-resistant ring is made of polyurethane, polytetrafluoroethylene, and synthetic resin with cloth. The width of the piston is determined by the size of the seal and the necessary length of the sliding part. If the sliding part is too short, it is easy to cause early wear and jamming. The material of the piston is usually aluminum alloy and cast iron. The piston of the small cylinder is made of brass. As shown in Figure 2
4) Piston rod
The piston rod is the most important force-bearing part in the cylinder. High carbon steel is usually used, the surface is hard chrome-plated, or stainless steel is used to prevent corrosion and improve the wear resistance of the seal.
5) Sealing ring
The seal of the rotating or reciprocating part is called a dynamic seal, and the seal of the stationary part is called a static seal.
There are several main connection methods between the cylinder barrel and the end cover: integral type, riveted type, threaded connection type, flange type, and tie rod type. 6) When the cylinder is working, the piston must be lubricated by the oil mist in the compressed air. There are also a small number of lubrication-free cylinders.