Jet Pipe Servo Valve is a kind of high-precision control element widely used in hydraulic control system, especially in the industrial and aerospace fields which require high response speed and control accuracy. It can control the actuator (such as hydraulic cylinder or hydraulic motor) accurately by controlling the flow direction and flow rate of hydraulic oil.
First, the basic structure of jet tube servo valve
Jet tube servo valve is mainly composed of the following parts:
1. Torque motor: As the input control part of servo valve, it usually consists of permanent magnet, coil and armature. When the input current signal changes, the electromagnetic force changes and drives the armature to move.
2. Jet pipe assembly: including nozzle and receiving pipe (or control hole). The jet pipe is installed under the drive of torque motor and can swing between two receiving pipes, thus controlling the flow direction of hydraulic oil.
3. Main spool and main valve body: constitute a hydraulic amplification stage, and control the movement of the main spool through the pressure difference output by the jet pipe, thereby controlling the flow direction and flow rate of large-flow hydraulic oil.
4. Feedback mechanism: usually mechanical feedback, used to improve the stability and control accuracy of the system.
Second, the working principle
The working process of jet tube servo valve can be divided into three stages: electrical signal input, hydraulic primary control and hydraulic power amplification.
1. Signal input stage: When the controller outputs a current signal to the torque motor of the servo valve, the current in the coil generates a magnetic field, which changes the position of the armature and drives the jet tube to deflect.
2. Primary hydraulic control: after the jet tube is deflected, the flow direction of the oil sprayed from the nozzle is changed, resulting in a pressure difference between the two receiving cavities. This pressure difference becomes the control signal for subsequent hydraulic amplification.
3. Power amplification stage: the main valve core moves under the action of the above pressure difference, changing the opening of the main valve port, thus controlling the flow and direction entering the actuator. The displacement of the main spool is proportional to the input signal, which realizes high precision control.
Third, the characteristics of jet tube servo valve
-Fast response speed: Due to simple structure, small inertia and short response time, the jet pipe is suitable for high-frequency control.
-Compact structure and high reliability: no slide valve structure, little wear and long service life.
-Strong anti-pollution ability: the jet pipe has a large gap and is not easily blocked by impurities in hydraulic oil.
-High control accuracy: micron positioning accuracy can be achieved through closed-loop feedback.
Fourth, the application field
Jet tube servo valve is widely used in many high-precision control fields because of its excellent performance, such as:
-Aerospace: flight control system, steering gear control.
-Industrial automation: CNC machine tools and robot servo systems.
-Test equipment: material testing machine, vibration table and other systems requiring high dynamic performance.
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To sum up, jet tube servo valve plays an irreplaceable role in modern hydraulic servo control system with its fast response, high precision and good anti-pollution ability. With the continuous progress of technology, its performance will be more superior and its application scope will be further expanded. For engineers and technicians engaged in the design and maintenance of hydraulic control system, it is of great significance to deeply understand its working principle.