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As an efficient and reliable way of power transmission, hydraulic system is widely used in many fields. Liquid is used as the transmission medium, and the actuator is driven by pressure changes to achieve high-precision and high-load motion control. This article will discuss the working principle of hydraulic system, introduce its main components and several common hydraulic system structures.
01. Working principle of hydraulic system
In the hydraulic system, the hydraulic pump converts mechanical energy into hydraulic energy, transfers energy through the flow of oil in the pipeline, and then the actuator (such as a hydraulic cylinder or a hydraulic motor) converts hydraulic energy into mechanical energy to complete specific work tasks. The basic working process of the hydraulic system is as follows:
Hydraulic pump operation: The hydraulic pump sucks in oil and pressurizes it to send the oil into the hydraulic system. This is the power source of the entire system. The function of the hydraulic pump is to convert mechanical energy into hydraulic energy.
Hydraulic oil flow and control: Through control valves (such as directional valves, flow valves, and pressure valves), the system controls the flow direction, flow rate, and pressure of the oil. These control elements ensure that the hydraulic system operates according to predetermined requirements.
Actuator operation: Hydraulic oil flows through the pipeline and enters the actuator (such as a hydraulic cylinder or a hydraulic motor) after control. The hydraulic cylinder completes the output of force or mechanical energy through the linear motion of the piston or the rotational motion of the hydraulic motor, thereby driving the mechanical equipment to complete the work.
Hydraulic oil returns to the tank: After work is completed, the oil returns to the tank through the oil return pipe and enters the next round of circulation.
02. Composition of hydraulic system
The hydraulic system consists of the following five main parts:
1. Power element
The power element is mainly a hydraulic pump, which converts mechanical energy into hydraulic energy. The hydraulic pump sucks in hydraulic oil and pressurizes it, sending the oil into the system to provide the required power for other components. Common types of hydraulic pumps include gear pumps, plunger pumps and vane pumps.
2. Actuator
The actuator is usually a hydraulic cylinder or hydraulic motor, which is responsible for converting hydraulic energy into mechanical energy to complete specific work tasks. The hydraulic cylinder achieves force output through the linear motion of the piston, while the hydraulic motor drives the mechanical parts through rotational motion.
3. Control elements
The function of control elements is to adjust and control the flow direction, flow rate and pressure of the oil to meet the working requirements of the system. Common control elements are directional valves, pressure valves and flow valves. Through these control valves, the system can achieve precise operations, such as controlling the movement direction, speed and force of the hydraulic cylinder.
4. Auxiliary elements
Auxiliary elements include oil tanks, filters, coolers, pressure sensors, etc. Although these components are not directly involved in power conversion, they play a role in supporting and protecting the system to ensure the normal operation and long-term stability of the system.
5. Working medium
The working medium is mainly hydraulic oil, which is the medium for transmitting power in the hydraulic system. Hydraulic oil is not only responsible for power transmission, but also plays the role of lubrication, cooling, cleaning and anti-corrosion.
03.Structural form of hydraulic system
The structural forms of hydraulic systems are mainly divided into three types according to the installation position of the hydraulic pump:
1. Vertical: This installation method is to place the hydraulic pump vertically on the cover of the oil tank. It is usually used in quantitative pump systems, that is, systems with a fixed flow rate. The vertical installation design is relatively simple and saves space. It is also conducive to the flow and heat dissipation of the oil. Due to the compact structure, the connection between the oil tank and the pump is also more direct, which is suitable for occasions with high space requirements.
2. Horizontal: This method is to install the hydraulic pump horizontally on the oil tank cover, which is suitable for variable pump systems that need to adjust the flow. Horizontal installation can easily adjust the flow, which is very important for systems that need to adjust the pressure or flow according to load changes. This design is stable and easy to maintain, and is suitable for hydraulic systems with unstable flow and more flexible control.
3. Side-mounted: The hydraulic pump of this type is installed horizontally next to the oil tank. This structure is suitable for hydraulic systems with large oil tank capacity and high motor power, and can also be equipped with a backup pump.
