A complete hydraulic system consists of five parts, namely power components, actuators, control components, auxiliary components and hydraulic medium.

The function of the power element is to convert the mechanical energy of the prime mover into the pressure energy of the liquid, which refers to the oil pump in the hydraulic system, which provides power to the entire hydraulic system. The structural forms of hydraulic pumps generally include gear pumps, vane pumps and plunger pumps.

The function of the actuators (such as hydraulic cylinders and hydraulic motors) is to convert the pressure energy of the liquid into mechanical energy, and drive the load to perform linear reciprocating motion or rotary motion.

Control elements (ie, various hydraulic valves) control and regulate the pressure, flow and direction of liquids in hydraulic systems. According to the 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, regulating valve, diverter collecting valve, etc.; directional control valve includes check valve, Hydraulic control check valve, shuttle valve, reversing valve, etc. According to different control methods, hydraulic valves can be divided into on-off control valves, fixed value control valves and proportional control valves.

Auxiliary components include oil tank, oil filter, oil pipe and pipe joint, sealing ring, pressure gauge, oil level oil temperature gauge, etc. Hydraulic oil is the working medium that transmits energy in the hydraulic system. There are various types of mineral oils, emulsions and synthetic hydraulic oils.

Hydraulic parts are all components used in hydraulic systems such as hydraulic pumps, hydraulic motors, hydraulic cylinders, hydraulic valves, and boosters.

The failure of hydraulic parts leads to noise, and the air suction phenomenon is one of the main reasons for the excessive noise of the hydraulic pump. The hydraulic pump distribution plate is also one of the important components that easily cause noise.