Hydraulic cylinders convert hydraulic energy into mechanical energy, enabling linear reciprocating or oscillating motion. They have a simple structure and provide smooth reciprocating movement, thus finding extensive application in various construction machinery, ships, and machine tool industries.

Different machines require different types of hydraulic cylinders. Cylinders are mainly classified into piston cylinders, plunger cylinders, and swing cylinders based on their structural form, each type having its own specific function.

There are two types of hydraulic cylinder pistons: single-piston and double-piston cylinders. The single-piston hydraulic cylinder has a piston rod at only one end, with both ends serving as oil outlet and return ports, enabling bidirectional movement. This is also known as a double-acting cylinder, commonly used in construction machinery like hydraulic excavators.

The twin-piston hydraulic cylinder features extended piston rods at both ends, with a composition similar to that of a single-piston rod cylinder. When the right chamber of the cylinder is filled with oil and the left chamber returns the oil, the piston moves to the left; otherwise, it moves to the right.

Hydraulic cylinders have pistons with identical rod diameters on both sides, resulting in equal effective working areas at each piston end. When the same pressure and flow of oil are introduced into both ends, the pistons produce equal thrust and reciprocating speeds. Such cylinders are commonly used in applications where the reciprocating speed is the same but the thrust is minimal, such as on a grinding machine's worktable.