Working principle of the hottest servo valve

2022-09-23
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Working principle of servo valve

typical servo valve is composed of permanent magnet torque motor, nozzle, baffle, valve core, valve sleeve and control chamber (see Figure). When the input coil is energized with current, the baffle moves to the right, strengthening the throttling effect of the right nozzle, reducing the flow and increasing the right back pressure; At the same time, the throttling effect of the left nozzle decreases, the flow increases, and the left back pressure decreases. The force at both ends of the valve core loses balance, and the valve core moves to the left. High pressure oil flows from s to C, adopts a unique heat cut-off structure and heat storage 2, and is sent to the load. The load return oil flows through the oil return port through C1 and enters the oil tank. The displacement of the valve core is proportional to the input current of the torque motor, and the hydraulic pressure acting on the valve core is balanced with the spring force. Therefore, in the balanced state, the differential current of the torque motor is proportional to the displacement of the valve core. If the input current is reversed, the flow is also reversed. The classification of servo valves is shown in the table

servo valve is mainly used in electric hydraulic servo system as actuator (see hydraulic servo system). In the servo system, compared with electrical and pneumatic actuators, hydraulic actuators have the characteristics of good rapidity, large output power per unit weight, stable transmission, strong anti-interference ability and so on. On the other hand, electrical components are often used when transmitting signals and correcting characteristics in servo systems. Due to the combination of signal comparison, component exchange and other methods, modern high-performance servo systems also adopt electro-hydraulic mode, and servo valve is the necessary component for the two-phase construction of this system

servo valve has complex structure, high cost and high requirements for oil quality and cleanliness. New servo valves are trying to overcome these shortcomings, such as the servo valve using electrostrictive elements, which greatly simplifies the structure. Another direction including the maximum non seizure load Pb is to develop special working oils (such as electric viscous oils). This kind of working oil can change the viscosity coefficient under the action of electromagnetism. Using this property, the oil flow can be directly controlled by electrical signals

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