The structure of hydraulic cylinders is diverse, and the classification methods are also diverse: according to the movement mode, it can be divided into linear reciprocating type and rotary swing type; according to the function of hydraulic pressure, it can be divided into single-acting type and double-acting type; according to structure type, it can be divided into piston type, plunger type, multi-stage telescopic sleeve type, rack and pinion type, etc.

Telescopic hydraulic cylinders have two or more pistons. The extension sequence of the telescopic hydraulic cylinder piston is from large to small, while the no-load retraction sequence is generally from small to large. The telescopic cylinder has long stroke, short telescopic length and compact structure. This hydraulic cylinder is often used in construction machinery and agricultural machinery. When each piston moves successively, the output speed and output force of the multi-motion piston are variable.

Piston hydraulic cylinders can be divided into two types: single rod type and double rod type. The fixing method is cylinder block and piston rod type. According to the role of hydraulic pressure, there are single-acting and double-acting. In a single-acting hydraulic cylinder, the pressure oil is only supplied to one cavity of the hydraulic cylinder. The hydraulic cylinder can move on one side, while the reverse movement is realized by external force (such as spring force, dead weight or external load). The piston can move within two Ds. Alternate directions through two air chambers and hydraulic pressure. The piston hydraulic cylinder has only one piston rod on the piston side, so the effective areas of the two chambers are different. When the fuel supply is the same, the piston moves at different speeds in different chambers; when the load to be overcome is the same, the pressures to be supplied in different chambers are different, or after adjusting the system pressure, the two hydraulic cylinders of the sanitary garbage truck The load to be overcome in each direction is different.

The rotary hydraulic cylinder is an actuator that outputs torque and realizes reciprocating motion. It has several forms, such as single-edged, double-edged and spiral swing. Blade type: The stator base is fixed on the cylinder block, and the blade and the rotor are connected together. According to the oil inlet direction, the blade drives the rotor to swing back and forth. The spiral swing type is divided into a single spiral swing type and a double spiral swing type. Now the double helix is commonly used. The linear motion of the piston in the two screw hydraulic cylinders is converted into a compound motion of linear motion and rotary motion, so as to realize the swing motion.