A hydraulic cylinder is a hydraulic device that converts hydraulic energy into mechanical energy and performs linear reciprocating or swinging motion. A hydraulic cylinder is a hydraulic actuator that converts hydraulic energy into mechanical energy and performs linear reciprocating motion (or swinging motion). It has a simple structure and reliable operation. When used to achieve reciprocating motion, the reducer can be omitted and there is no transmission gap, so hydraulic cylinders are widely used in various mechanical hydraulic systems. The output force of the hydraulic cylinder is proportional to the effective area of ​​the piston and the pressure difference on both sides of it. The hydraulic cylinder is basically composed of a cylinder and a cylinder head, a piston and a piston rod, a sealing device, a buffer device and an exhaust device. The buffer device and the exhaust device depend on the specific application, and other devices are also necessary. The hydraulic cylinder has a simple structure and a smooth reciprocating motion. It is widely used in various engineering machinery, ships, machine tools and even defense equipment industries.