Torque motor servo valve is a key component in hydraulic servo control system, which is widely used in aerospace, industrial automation, precision machinery and other fields. Its main function is to convert electrical signals into hydraulic signals (pressure or flow), so as to realize high-precision control of actuators (such as hydraulic cylinders or hydraulic motors). This paper will introduce the structure, working principle and electro-hydraulic signal conversion process of torque motor servo valve in detail.
First, the basic structure of torque motor servo valve
Torque motor servo valve usually consists of the following parts:
1. Torque Motor: As an electro-mechanical conversion element, it receives the input current signal and generates the corresponding electromagnetic torque.
2. Nozzle baffle mechanism: used to convert the mechanical motion of the torque motor into the change of hydraulic pressure.
3. Slide valve assembly (main valve core): control the flow direction and flow rate of hydraulic oil according to the pressure change of nozzle baffle.
4. Feedback mechanism: feedback of valve core displacement is realized by mechanical or hydraulic means to ensure the stability and accuracy of control.
Second, the working principle and signal conversion process
The core function of torque motor servo valve is to convert the input electrical signal into hydraulic output, and the conversion process can be divided into the following stages:
# 1. Input electric signal to drive torque motor
When the controller sends out a current signal (usually ±10mA or ±40mA), current will flow in the coil inside the torque motor, and a rotating torque proportional to the current will be generated in the magnetic field. This moment deflects the baffle around the fulcrum and changes the gap between the nozzle and the baffle.
# 2. Pressure difference generated by nozzle baffle mechanism
Deflection of baffle will change the flow area of two symmetrical nozzles, resulting in pressure imbalance in nozzle cavity. For example, when the nozzle on one side is approached by the baffle, the pressure on this side increases and the pressure on the other side decreases, thus forming a pressure difference.
# 3. The pressure difference drives the slide valve to move
The pressure difference of the nozzle cavity acts on both ends of the slide valve, pushing the slide valve to move to the low pressure side. The movement of the slide valve changes the flow channel of hydraulic oil, so that the high-pressure oil flows to one chamber, while the other chamber returns oil, thus forming a flow output.
# 4. Feedback mechanism to achieve closed-loop control
The displacement of the slide valve is connected with the torque motor through a feedback rod or a spring to form negative feedback. When the spool valve reaches the position corresponding to the input current, the feedback torque cancels the input torque, and the system reaches a new equilibrium state, thus realizing high-precision control.
Third, the characteristics and advantages
-Fast response: The torque motor responds quickly, which makes the servo valve have good dynamic performance.
-High control accuracy: Through the closed-loop feedback mechanism, positioning control with micron level or even higher accuracy can be realized.
-strong adaptability: suitable for various hydraulic systems, especially for closed-loop control occasions with high precision requirements.
Fourth, the application field
Because of its excellent control characteristics, torque motor servo valve is widely used in:
-Hydraulic servo mechanism of aerospace flight control system;
-Precise position control of industrial robots and CNC machine tools;
-Dynamic loading in automobile test-bed and simulation system;
-All kinds of hydraulic servo test equipment, etc.
tag
To sum up, the torque motor servo valve realizes high-precision control of the hydraulic system by efficiently and accurately converting the input electrical signal into the corresponding hydraulic output. Its working principle involves the coupling of electric-mechanical-hydraulic multi-physical fields, and it is an indispensable core component in modern hydraulic servo system. With the development of intelligent manufacturing and automation technology, torque motor servo valve will play an important role in more high-precision and high-performance applications.