, Product performance and uses: a complete hydraulic system consists of five parts, namely, power components, actuators, control components, auxiliary components and hydraulic oil. A complete hydraulic system consists of five parts, namely, power components, actuators, control components, auxiliary components and hydraulic oil. The role of the element of the power hydraulic element is the original motivation of the mechanical energy is converted into fluid pressure, means of the hydraulic system of pumps, it is to provide power to the entire hydraulic system. The general structure of hydraulic pump gear pumps, vane pumps and piston pumps. Actuators (such as hydraulic cylinders and hydraulic motors) the role of the pressure of the liquid can be converted to mechanical energy to drive the load for the reciprocating linear motion or rotary motion. Control elements (ie, hydraulic valve) to control and adjust the pressure, flow and direction of the liquid in the hydraulic system. Different hydraulic valve control functions can be divided into the pressure control valves, flow control valves and directional control valves. The pressure control valve is divided into the relief valve (safety valve), pressure reducing valves, sequence valves, pressure relay; flow control valves including throttle, adjusting valves, flow diversion valve; directional control valves including unidirectional valves, pilot-operated check valve, shuttle valve, valve. Depending on the control mode, the hydraulic valve can be divided into the switch control valve setpoint control valve proportional control valve. Auxiliary components, including the fuel tank, oil filter, tubing and pipe joints, seals, pressure gauge, oil level, oil temperature meter. Hydraulic oil is the working medium to transfer energy in the hydraulic system, a variety of mineral oil, the emulsion oil hydraulic molding Hop broad categories.