Facts About Hydraulics

Hydraulic is a term for machinery industry and electromechanical industry. Hydraulic power can be used as a power transmission. Hydraulic pressure can also be used as a control method, which is called hydraulic pressure control. Hydraulic transmission uses liquid as the working medium and uses the pressure energy of the liquid to transmit power. Hydraulic control is based on the transmission of control signals with pressure liquid. 

The control system composed of hydraulic technology is called a hydraulic control system. Hydraulic control usually includes hydraulic open-loop control and hydraulic closed-loop control. The hydraulic closed-loop control is also the hydraulic servo control. It constitutes a hydraulic servo system, which usually includes an electric hydraulic servo system (electro-hydraulic servo system) and a mechanical hydraulic servo system (mechanical-hydraulic servo system, or mechanical-hydraulic servo mechanism).

A complete hydraulic system consists of five parts, namely energy device, actuator, control device, auxiliary device, and liquid medium. Hydraulic is widely used in industrial and civil industries due to its large transmission power, easy transmission and configuration. The role of the hydraulic system's actuators (hydraulic cylinders and hydraulic motors) is to convert the pressure energy of the liquid into mechanical energy, to obtain the required linear reciprocating or rotary motion. The energy device of the hydraulic system (hydraulic pump) is used to convert the mechanical energy of the prime mover into the pressure energy of the liquid.

Composition of hydraulic system

A complete hydraulic system consists of five parts, namely power elements, actuators, control elements, auxiliary components and working medium. The role of the power element is to convert the mechanical energy of the prime mover into the pressure energy of the liquid. 

Power element refers to the hydraulic pump in the hydraulic system, which provides power to the entire hydraulic system. The structure of the hydraulic pump is generally gear pump, vane pump, plunger pump, screw pump. The function of the actuator is to convert the pressure energy of the liquid into mechanical energy, and drive the load to perform a linear reciprocating motion or a rotary motion. The actuators are hydraulic cylinders and hydraulic motors. 

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 valves are further divided into relief valves (relief valves), pressure reducing valves, sequence valves, pressure relays, etc. .; flow control valves include throttle valves, regulating valves, diverter manifolds, etc. .; directional control valves include check valves, Hydraulically controlled check valve, shuttle valve, directional 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 accumulators, filters, coolers, heaters, oil pipes, pipe joints, fuel tanks, pressure gauges, flow meters, sealing devices, etc. They play an auxiliary role in connecting, storing, filtering and measuring oil pressure Refer to "Hydraulic Transmission" and "Hydraulic System Design Series”. The working medium refers to the hydraulic oil or emulsion in various hydraulic transmissions. There are several types of mineral oil, emulsion and synthetic hydraulic oil. The hydraulic system realizes movement and power transmission through it.