Nozzle flapper servo valve is a kind of high-precision control element widely used in hydraulic control system, which has the characteristics of fast response and high control accuracy. It plays an important role in aerospace, industrial automation, precision machinery and other fields. In this paper, the structure principle and flow regulation mechanism of nozzle baffle servo valve will be introduced in detail.
1. Structure and working principle of nozzle baffle servo valve
The nozzle baffle servo valve is mainly composed of nozzle, baffle, slide valve, feedback mechanism and control coil. Its working principle is based on the change of the gap between the baffle and the nozzle, thus changing the pressure distribution of the fluid, further pushing the slide valve to move and controlling the flow and direction of the hydraulic oil.
Under normal working conditions, the baffle is located between the two nozzles, and the tiny displacement is adjusted by electromagnetic force or mechanical force. When an input signal (usually an electrical signal) acts on the control coil, the coil generates a magnetic field, which makes the armature drive the baffle to move and change the gap between the baffle and the two nozzles. The change of this gap leads to the imbalance of pressure on both sides of the nozzle, which pushes the slide valve to move and changes the on-off state and flow rate of the oil circuit.
Second, the basic mechanism of flow regulation
The nozzle flapper servo valve can accurately control the flow by adjusting the position of the flapper. Specifically, when the baffle is close to a nozzle on one side, the back pressure of the nozzle on the other side increases, while that on the other side decreases. This pressure difference drives the displacement of the slide valve, and then changes the opening of the valve port, and finally realizes the regulation and control of the oil flow in the hydraulic system.
The output flow of the servo valve is proportional to the input signal. By accurately controlling the magnitude and direction of the signal current, the high-precision control of the movement speed and position of the actuator (such as hydraulic cylinder or hydraulic motor) can be realized.
Third, factors affecting the accuracy of flow regulation
1. Structural accuracy and manufacturing tolerance: The internal components of servo valve (such as nozzle, baffle, slide valve, etc.) must have extremely high machining accuracy, otherwise the stability and repeatability of flow regulation will be affected.
2. Fluid pollution: impurities in hydraulic oil may block the nozzle or wear the slide valve, resulting in inaccurate flow control. Therefore, keeping the hydraulic system clean is the key to ensure the performance of servo valve.
3. Temperature change: Temperature change will affect the viscosity of hydraulic oil, thus affecting the flow characteristics. High-quality servo valves usually have temperature compensation function to improve control stability.
4. Stability of control signal: The servo valve is controlled by electric signal, so the stability and anti-interference ability of signal source also directly affect the effect of flow regulation.
Fourth, adjustment and maintenance in practical application
In the practical application process, the nozzle flapper servo valve needs to be adjusted and maintained regularly. Calibration usually includes zero adjustment, gain adjustment and frequency response test. In terms of maintenance, the filter element should be replaced regularly, the wear of the valve element should be detected, and the cooling and lubrication measures should be adjusted according to the use environment.
tag
The nozzle baffle servo valve realizes the precise control of the hydraulic system flow through the slight gap change between the baffle and the nozzle. It has compact structure, rapid response and high control precision, and is suitable for occasions with strict control performance requirements. Understanding its working principle and adjustment mechanism is of great significance for optimizing the performance of hydraulic system and improving the operation efficiency of equipment. In the process of use, paying attention to adjustment and daily maintenance is helpful to prolong the service life of servo valve and ensure the stable operation of the system.