In modern ship control system, steering gear is the key equipment to realize ship steering, and its performance directly affects the maneuverability and safety of the ship. The servo valve is the core component in the hydraulic control system of the steering gear, which plays a vital role in the control process of the steering gear. This paper will discuss the driving principle, structural characteristics and related problems in practical application of servo valve of ship steering gear.
First, the basic function of servo valve
Servo valve is a kind of high-precision hydraulic control valve, which is mainly used to adjust the flow and pressure of oil in the hydraulic system, so as to realize the accurate control of the position, speed and force of the actuator (such as steering gear hydraulic cylinder). In the ship steering gear, the servo valve receives the electric signal from the steering gear and converts it into hydraulic signal, thus accurately controlling the steering angle deflection.
Second, the working principle of servo valve
The drive of servo valve depends on electro-hydraulic conversion mechanism. Its basic working principle is as follows:
1. Signal input: The steering device (such as the steering wheel or autopilot system on the bridge) sends out command signals, usually electrical signals.
2. Electro-hydraulic conversion: the electric signal is input to the torque motor inside the servo valve, which drives the valve core to move.
3. Hydraulic control: the displacement of the valve core changes the flow direction and flow rate of hydraulic oil, thus controlling the movement direction and speed of the piston of the hydraulic cylinder.
4. Feedback adjustment: The system is equipped with a position feedback device (such as differential transformer LVDT) to feed back the actual position of the rudder to the control system to form a closed-loop control to ensure the high-precision tracking of the rudder angle.
Three, the main types of servo valve
Servo valves commonly used in ship steering gear include:
-Nozzle flapper servo valve: simple structure, fast response, suitable for medium and low power systems.
-Jet tube servo valve: strong anti-pollution ability, suitable for harsh working environment.
-Direct-drive servo valve: It has high control accuracy and fast response speed, but its cost is high. It is often used in high-performance ship control systems.
Four, the key factors of servo valve drive
1. Stability of power supply and control signal: Servo valve is very sensitive to the fluctuation of input signal, so it is necessary to ensure the stability and reliability of power supply and signal line of steering system.
2. Cleanliness of hydraulic medium: The internal clearance of the servo valve is extremely small, which is easy to be stuck or worn due to oil pollution, so it is necessary to replace the oil filter regularly to keep the hydraulic oil clean.
3. System pressure and flow matching: The normal operation of the servo valve depends on the appropriate system pressure and oil supply flow, and the hydraulic pump station must be reasonably configured according to the power of the steering gear.
V. Application and Development Trend of Servo Valve
With the improvement of ship automation level, the application of servo valve in steering gear system is becoming increasingly intelligent. Modern ships generally use electro-hydraulic servo system, combined with PLC, CAN bus and other technologies, to achieve remote control, automatic rectification, fault diagnosis and other functions. In the future, with the development of new materials and electronic technology, servo valves will further develop in the direction of miniaturization, energy saving and intelligence.
VI. Conclusion
To sum up, the servo valve is the core component of the ship steering gear system to achieve high precision control, and its driving mode directly affects the response speed and control accuracy of the steering gear. Reasonable selection, standardized operation and regular maintenance are the keys to ensure the stable operation of servo valves. By continuously optimizing the servo control system, the safety and maneuverability of ship navigation will be further improved, which will provide a strong guarantee for the development of modern shipping industry.