A complete hydraulic system consists of five parts, namely power elements, actuators, control elements, auxiliary elements and hydraulic oil.
The role of the power element is to convert the mechanical energy of the prime mover into the pressure energy of the liquid, referring to the oil pump in the hydraulic system, which provides power to the entire hydraulic system. The structure of the hydraulic pump is generally a gear pump, a vane pump and a plunger pump. Actuators (such as hydraulic cylinders and hydraulic motors) convert the pressure energy of the liquid into mechanical energy, and drive the load to perform linear reciprocating or rotary motion. Control elements (ie various hydraulic valves) control and regulate the pressure, flow and direction of the liquid in the hydraulic system. According to different control functions, hydraulic valves can be divided into pressure control valves, flow control valves and directional control valves. Pressure control valve is divided into relief valve (safety valve), pressure reducing valve, sequence valve, pressure relay, etc.; flow control valve includes throttle valve, adjusting valve, diverter flow valve, etc.; direction control valve includes check valve, Hydraulic check valves, shuttle valves, reversing valves, etc. According to different control methods, hydraulic valves can be divided into switch type control valves, fixed value control valves and proportional control valves. The auxiliary components include fuel tanks, oil filters, tubing and fittings, seals, pressure gauges, and oil level oil thermometers. Hydraulic oil is the working medium for transmitting energy in the hydraulic system. There are several types of mineral oil, emulsion and synthetic hydraulic oil.