Types of Hydraulic Cylinders And Their Characteristics

1. Piston-Type Hydraulic Cylinder

A single-rod piston hydraulic cylinder has a piston rod on only one side. It is a type of single-piston hydraulic cylinder. Both ports A and B can be used for pressurized oil input or return oil, allowing bidirectional motion, hence it is called a double-acting cylinder.
The piston itself can only move in one direction under pressure; movement in the opposite direction requires an external force. However, piston-type hydraulic cylinders generally have a longer stroke compared to others.

2. Plunger-Type Hydraulic Cylinder

1. The plunger-type hydraulic cylinder is a single-acting cylinder, which can only move in one direction by hydraulic pressure. The return movement of the plunger relies on external forces or the plunger’s own weight.

2. The plunger is supported only by the cylinder sleeve and does not come into contact with it. This makes the sleeve easier to manufacture, making it suitable for long-stroke applications.

3. The plunger is always under pressure during operation and thus must have sufficient rigidity.

4. The plunger is usually heavy. When placed horizontally, it tends to sag due to its own weight, which may cause uneven wear on seals and guide components. Therefore, vertical use is more favorable.

3. Telescopic Hydraulic Cylinder

Telescopic hydraulic cylinders feature two or more stages of pistons. In a telescopic cylinder, the pistons extend in sequence from the largest to the smallest, and typically retract from the smallest to the largest.
This type of cylinder can achieve a long stroke with a compact retracted length, making the structure more compact.
It is commonly used in construction and agricultural machinery. Since multiple pistons move in succession, both the output speed and force vary during operation.

4. Rotary (Oscillating) Hydraulic Cylinder

The rotary or oscillating hydraulic cylinder is an actuator that outputs torque and performs reciprocating rotary motion, also known as a rotary hydraulic motor.
There are two types: single-vane and double-vane.
The stator block is fixed to the cylinder body, while the vane and rotor are connected together. Depending on the oil flow direction, the vane drives the rotor to perform a reciprocating oscillating motion.