Servo valve is a key control element in hydraulic system, which is widely used in high precision and high response industrial and aviation fields. Among them, the hydraulic Chinese servo valve is widely favored because of its compact structure, rapid response and high control accuracy. This paper will focus on the theme of “how to realize the balance of Chinese servo valve by hydraulic pressure”, and analyze the structural principle, working process and key factors to realize the balance.
First, the basic structure of hydraulic alignment Chinese servo valve
Hydraulic Chinese servo valve is usually composed of torque motor (or electromagnetic coil), nozzle baffle mechanism, slide valve and feedback mechanism. Its core lies in the “centering” design, that is, when the system is at rest, the slide valve is in the middle position, the oil inlet and the oil outlet are closed, and the system is in a balanced state.
Second, the establishment process of equilibrium state
When the servo valve is not energized, the slide valve is in the neutral position under the action of spring or hydraulic pressure. At this point, the oil can’t circulate, and the system keeps static balance. When the controller sends out an electrical signal, the torque motor generates magnetic force, which drives the baffle to deviate and changes the gap between the nozzle and the baffle, thus causing pressure change.
This pressure change pushes the slide valve to move, changes the oil channel, and makes the hydraulic actuator (such as hydraulic cylinder or motor) act. As the slide valve moves, the feedback mechanism (such as spring or mechanical connection) feeds back the displacement of the slide valve to the baffle mechanism, forming closed-loop control, and finally returning the slide valve to a new equilibrium position.
Third, the key factors to achieve balance
1. Feedback mechanism: the servo valve adopts negative feedback mechanism, which counteracts the influence of input signal through the displacement feedback of slide valve, thus stabilizing the system output. The accuracy and rigidity of the feedback mechanism directly affect the balance performance of the system.
2. Hydrodynamic balance: the slide valve will be affected by hydrodynamic force during the movement. The symmetry of hydraulic force should be considered in the design, so that the force of the slide valve is balanced when it moves in the positive and negative direction, and the imbalance caused by offset can be avoided.
3. Matching of electromagnetic force and reset force: the electromagnetic force generated by the torque motor must match the reset spring force and hydraulic force to ensure that the slide valve can accurately respond to the input signal and automatically return to the center after the signal disappears.
4. Manufacturing and assembly accuracy: the internal clearance of servo valve is very small, and the machining accuracy and assembly quality of parts are very important to the dynamic response and static balance of the system.
IV. Conclusion
Through precise structural design and closed-loop feedback mechanism, the hydraulic Chinese servo valve realizes dynamic balance under various working conditions. Its balance performance depends not only on the reasonable mechanical structure, but also on the synergy of electromagnetic, hydraulic and feedback systems. With the development of material science and control technology, the balance of servo valve will be further improved, which will provide more reliable and stable support for high-precision hydraulic control system.
(The full text is about 650 words)