Piston type
A single piston rod hydraulic cylinder has a piston rod at only one end. The inlet and outlet oil ports a and B at both ends can be supplied with pressure oil or return oil to realize two-way movement, so it is called double acting cylinder. The piston can only move in one direction, and its reverse movement needs to be completed by external force. But its stroke is generally larger than that of the piston type hydraulic cylinder.
The piston type hydraulic cylinder can be divided into two types: single rod type and double rod type. Its fixing methods are cylinder body fixing and piston rod fixing. According to the action of hydraulic pressure, there are single acting type and double acting type. In the single acting hydraulic cylinder, the pressure oil is only supplied to one chamber of the hydraulic cylinder. The cylinder moves in one direction by the hydraulic pressure, and the reverse direction is realized by the external force (such as spring force, self weight or external load); The movement of the piston in two directions of the double acting hydraulic cylinder is completed by the action of hydraulic pressure through the alternate oil feeding of the two chambers.
Plunger type
(1) The plunger type hydraulic cylinder is a single acting hydraulic cylinder, which can only move in one direction by hydraulic pressure. The return stroke of the plunger depends on other external forces or the self weight of the plunger;
(2) The plunger is only supported by the cylinder liner and does not contact with the cylinder liner, so the cylinder liner is extremely easy to process, so it is suitable for making long stroke hydraulic cylinders;
(3) When working, the plunger is always under pressure, so it must have sufficient rigidity;
(4) The weight of the plunger is often large. When it is placed horizontally, it is easy to sag due to its own weight, resulting in unilateral wear of the seal and guide. Therefore, its vertical use is more favorable.
Telescopic
The telescopic hydraulic cylinder has two or more stages of pistons. The sequence of piston extension in the telescopic hydraulic cylinder is from large to small, while the sequence of no-load retraction is generally from small to large. The telescopic cylinder can achieve a long stroke, while the retraction length is short and the structure is compact. This kind of hydraulic cylinder is commonly used in construction machinery and agricultural machinery. There are a plurality of pistons that move once. When each piston moves one by one, its output speed and output force change.
Swing type
Swing type hydraulic cylinder is an actuator that outputs torque and realizes reciprocating motion. It has several forms such as single blade, double blade and spiral swing. Vane type: the stator block is fixed on the cylinder block, and the blades and the rotor are connected together. According to the oil inlet direction, the blade will drive the rotor to reciprocate. Spiral swing type is divided into single spiral swing and double spiral. Now double spiral is commonly used. The linear motion of the piston in the hydraulic cylinder is transformed into the compound motion of linear motion and self rotation motion by two spiral pairs, so as to realize the swing motion.
