The structure and principle of hydraulic cylinders

A hydraulic cylinder is usually composed of main parts such as the rear end cover, cylinder barrel, piston rod, piston assembly and front end cover. To prevent the oil from leaking out of the hydraulic cylinder or from the high-pressure chamber to the low-pressure chamber, sealing devices are set between the cylinder barrel and the end cover, the piston and the piston rod, the piston and the cylinder barrel, and the piston rod and the front end cover. On the outside of the front end cover, a dust-proof device is also installed. In addition, to prevent the piston from rapidly retracting to the end of the stroke and hitting the cylinder head, a buffer device is also installed at the end of the hydraulic cylinder. Sometimes, an exhaust device is also required.

The specific components are introduced as follows:

1. Cylinder barrel: The cylinder barrel is the main component of a hydraulic cylinder. It forms a closed cavity together with the cylinder head, piston and other parts, driving the piston to move.

2. Cylinder head: The cylinder head is installed at both ends of the hydraulic cylinder and forms a tight oil chamber with the cylinder barrel. There are usually various connection methods such as welding, threading, bolts, keychains and tie rods. Generally, the selection is based on factors such as working pressure, the connection method of the oil cylinder and the usage environment.

3. Piston rod: The piston rod is the main component for transmitting force in a hydraulic cylinder, and its material is generally medium carbon steel (such as No. 45 steel).

4. Piston: The piston is the main component that converts hydraulic energy into mechanical energy. Its effective working area directly affects the force and movement speed of the hydraulic cylinder.

5. Guide sleeve: The guide sleeve serves to guide and support the piston rod. It is required to have high fit accuracy, low frictional resistance, good wear resistance, and be able to withstand the pressure, bending force, and impact vibration of the piston rod.

Principle

The hydraulic cylinder operates based on PASCAL's principle. When hydraulic oil is pumped into the cylinder body - side, the liquid pressure acts on the surface of the piston, causing it to move to the opposite side and driving the piston rod to output thrust or pull force. The structure of a hydraulic cylinder includes the cylinder body, pistons, seals and oil inlet and outlet ports. It achieves reciprocating motion by controlling the flow direction of the oil, converting the pressure energy of the hydraulic system into linear mechanical motion.