In hydraulic control system, servo valve, as the core control element, is widely used in high-precision and high-response automation equipment. Among them, the pilot servo valve has been widely used in the industrial field because of its structural characteristics and good control performance. This paper will focus on how to realize the signal amplification function of pilot servo valve and its key role in hydraulic control system.
First, the basic structure of pilot servo valve
Pilot servo valve usually consists of two parts: main valve and pilot valve. The main valve is responsible for the on-off and adjustment of large flow, while the pilot valve is the control part, usually a small electro-hydraulic servo valve or proportional valve. When the control system sends out a tiny electric signal, the signal first acts on the pilot valve, and then drives the main valve to act through hydraulic amplification, thus realizing accurate control of large-flow hydraulic oil.
This structural design enables the pilot servo valve to control a larger hydraulic system with a smaller input signal, thus realizing the “amplification” of the signal.
Second, the working principle of signal amplification
1. Primary signal input
The control system (such as PLC or controller) outputs a weak electrical signal, usually a milliampere or millivolt signal, which is input into the solenoid coil of the pilot valve.
2. Preliminary control of pilot valve
After the electromagnetic coil is excited by the electric signal, it generates corresponding electromagnetic force to push the valve core of the pilot valve to move. This movement changes the on-off state of the internal oil circuit of the pilot valve, and then changes the pressure of the control chamber.
3. Amplification of hydraulic signal
Because the pilot valve is connected to the control chamber of the main valve, its pressure change will directly affect the action of the main valve. The main valve is displaced under the pressure change of the control chamber, thus changing the opening of the main valve port, and finally controlling the flow and direction of hydraulic oil in the main circuit.
In this process, tiny electrical signals are converted into hydraulic signals through the pilot valve, and then the flow and pressure are amplified through the main valve, thus realizing the step-by-step amplification process from electrical signals to mechanical movements.
Third, advantages and applications
The advantages of pilot servo valve lie in its high response speed, large flow gain and good control accuracy. Through this signal amplification mechanism, it can realize efficient control of large hydraulic system without increasing the volume and power consumption of control components.
Common applications include aerospace, metallurgical equipment, heavy machinery, injection molding machines and other fields. For example, in the aircraft hydraulic control system, the pilot’s tiny operation signal can be amplified by the pilot servo valve, and the deflection angle of the aircraft rudder surface can be accurately controlled to ensure the flight stability and maneuverability.
Fourth, summary
To sum up, the pilot servo valve acts on the pilot stage first, then amplifies the signal step by step by using the hydraulic principle, and finally drives the main valve to control the large flow system. This signal amplification mechanism not only improves the response speed and control accuracy of the system, but also reduces the energy consumption and complexity of the control system. With the continuous development of modern hydraulic technology, the performance of pilot servo valve in signal amplification will continue to be optimized, and the hydraulic control technology will develop towards higher precision and higher efficiency.