Hydraulic systems


Hydraulic system is a system that uses oil as the working medium to drive the hydraulic actuator to work through the pressure energy of the oil. It is an important part in the fields of mechanical engineering, transmission and hydraulic transmission, and is mainly composed of five parts: power components, hydraulic actuators, control components, testing and auxiliary components and hydraulic fluids.


The five main parts of a hydraulic system include:

1. Power element: This is the "heart" of the hydraulic system, usually referring to the hydraulic pump. Its main function is to convert the mechanical energy provided by the prime mover (such as electric motor, internal combustion engine, etc.) into the hydraulic energy of the working fluid.

2. Actuator: This part is mainly the hydraulic motive, which converts the hydraulic energy of the working liquid into the mechanical energy of the driving load. Common actuators are hydraulic cylinders and hydraulic motors, which are used to achieve linear motion and rotary motion, respectively.

3. Control components: mainly including various hydraulic control valves, such as pressure control valves, flow control valves and directional control valves. The main function of these valves is to control and regulate the pressure, flow or flow direction of the working fluid to meet the transmission performance requirements of the hydraulic system.

4. Auxiliary components: this part includes fuel tank, oil filter, cooler, heater, accumulator, oil pipe and pipe joint, sealing ring, quick change joint, high-pressure ball valve, hose assembly, pressure measuring joint, pressure gauge, oil level gauge, oil thermometer, etc. These components play an auxiliary and protective role in the hydraulic system, ensuring the normal operation of the system.

5. Working medium: hydraulic oil and emulsion. They are not only carriers of energy, but also information carriers for condition monitoring and fault diagnosis of hydraulic systems. Commonly used hydraulic oils include mineral oils, animal and vegetable fats, and emulsions.


The working principle of the hydraulic system is: the hydraulic pump sucks the liquid from the oil tank, sends the liquid into the hydraulic valve through pressure, the hydraulic valve controls the flow direction and pressure of the liquid, and then sends the liquid into the hydraulic cylinder (or hydraulic motor), and the hydraulic cylinder (or hydraulic motor) converts the pressure of the liquid into mechanical energy to complete the corresponding work. After the work is completed, the liquid is controlled by the hydraulic valve to flow back into the hydraulic tank in preparation for the next work cycle.


Hydraulic systems have a variety of applications, including the defense industry, machine tool industry, metallurgical industry, automotive industry, textile industry, and shipbuilding industry. For example, hydraulic transmission and control technology has been widely used in the weapons and equipment of the navy, land and air forces in the national defense industry, grinders, drilling machines, milling machines and planers in the machine tool industry, and hydraulic off-road vehicles and hydraulic dump vehicles in the automobile industry.


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