1.The hydraulic cylinder is the actuator which make hydraulic energy of hydraulic system into mechanical energy, through the expansion and compression of the cylinder, implementation mechanism for a variety of actions, in order to meet the requirements of all kinds of equipment.

2.The hydraulic cylinder is divided into single and double acting cylinder, single acting cylinder starting action by hydraulic propulsion, reset action by load gravity or spring to achieve, the single hydraulic cylinder with an oil inlet and an exhaust port; and the expansion and contraction of the double acting cylinder are dependent on hydraulic oil pressure to achieve, there are inlet and outlet in the hydraulic cylinder.


3.In a power unit hydraulic circuit, the power unit control a single acting hydraulic cylinder or two single acting hydraulic cylinders or more than three cylinders, referring to the power unit in one operation allows for one or two or more cylinders operate simultaneously to achieve the same operation request; if the power unit to control a double-acting cylinders or more double-acting cylinders in a circuit, the same reason.


4.The power unit respectively in a hydraulic control a single acting cylinder or double acting cylinder, or several circuits’ cylinders.That is mean this power unit control different cylinders with different requirement,different time,but mutual non-interference, and some need to control the system and require simultaneous control, electronically controlled to achieve;with several circuits in the hydraulic system,they are the same as electronically controlled to achieve.