A cylindrical metal part that guides the piston to reciprocate linearly in the cylinder. Air expands in the engine cylinder to convert thermal energy into mechanical energy. The gas is compressed by the piston in the compressor cylinder to increase the pressure. Shells of turbines, rotary piston engines, etc. It is also commonly referred to as a "cylinder." Application areas of cylinders: printing (tension control), semiconductors (spot welders, grinding discs), automatic control, robots, etc.

　　 The cavity in the cylinder block of an internal combustion engine. It is the trajectory of the piston movement, in which gas burns and expands, and part of the explosion waste heat transferred by the gas can be dissipated through the cylinder wall, so that the engine maintains a normal operating temperature. There are two types of cylinders: monolithic and single-casting. Single casting type is divided into dry type and wet type. The cylinder block and the cylinder block are cast as a single body, which is called the integral cylinder block; when the cylinder and the cylinder block are cast separately, the single cast cylinder barrel is called the cylinder liner. Cylinder liners that are in direct contact with cooling water are called wet cylinder liners; cylinder liners that are not in direct contact with cooling water are called dry cylinder liners. In order to maintain the close contact between the cylinder and the piston and reduce the friction loss when the piston moves in it, the inner wall of the cylinder should have high machining accuracy and precise shape and size.

　　 Pneumatic actuators convert the pressure energy of compressed gas into mechanical energy in pneumatic transmission. There are two types of cylinders: reciprocating linear motion and reciprocating swing. The cylinders that perform reciprocating linear motion can be divided into four types: single-acting cylinders, double-acting cylinders, diaphragm cylinders and impact cylinders.

　　 Cylinder classification

　　①Single-acting cylinder: Only one end has a piston rod, and the air is supplied by one side of the piston to generate air pressure, which pushes the piston to generate thrust, and expands and contracts through a spring or its own weight.

　　②Double-acting cylinder: Air is supplied alternately from both sides of the piston, outputting force in one or two directions.

　　③Diaphragm cylinder: Replace the piston with a diaphragm, output force in one direction only, and return with a spring. The sealing performance is good, but the stroke is short.

　　④ Impact cylinder: This is a new element. It converts the pressure energy of the compressed gas into the kinetic energy of the piston's high-speed movement (10~20m/s) to perform work.

　　⑤Rodless cylinder: The general term for rodless cylinders. There are two types: magnetic cylinders and cable cylinders.

A cylinder that swings back and forth is called a swing cylinder. The inner cavity is divided into two parts by blades, and the gas is alternately supplied to the two cavities. The swing angle of the output shaft is less than 280°. In addition, there are rotating cylinders, gas-liquid damping cylinders, and stepping cylinders.

　　The joint surface of the cylinder with large deformation or serious steam leakage adopts the method of grinding and scraping the joint surface:

　　 If the joint surface of the upper cylinder is deformed within 0.05mm, the joint surface of the upper cylinder is used as the reference surface, and the joint surface of the lower cylinder shall be coated with red lead or embossed blue paper, and the lower cylinder shall be polished and scraped according to the traces. If the joint surface of the upper cylinder is deformed greatly, apply red lead on the upper cylinder, rub off the traces with a large flat ruler, and smooth the upper cylinder. Or the joint surface of the upper cylinder is smoothed by machining, and then the joint surface of the lower cylinder is polished and scraped on the basis of the upper cylinder.