Piezoelectric Ring Bender Servo Valve for Wear-Free Flow Control
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Solution Overview
Problem
Existing aircraft flight control and fuel control systems experience significant mechanical wear and tear due to the use of metal components like valves, springs, and flappers in servo valves, leading to reliability issues and maintenance challenges.
Innovation Solution
A piezoelectric ring bender servo valve assembly replaces the electromagnetic torque motor, flapper, and feedback spring with piezoelectric bendable members, a linear position sensing device, and valve control software to independently regulate fluid flow through nozzles, eliminating moving parts and reducing mechanical wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal components (valves, springs, flappers) are used in servo valves, then mechanical strength and structural stability are ensured, but mechanical wear and tear increases significantly
Solution Approach 1:
The patent replaces the electromagnetic torque motor with a piezoelectric actuator that directly positions the spool valve without mechanical flappers or springs. The piezoelectric material converts electrical signals directly into mechanical displacement, eliminating the need for electromagnetic components and their associated mechanical wear.
Solution Approach 2:
The patent removes the feedback spring component entirely from the system. Instead of using a mechanical spring to provide feedback force, the system uses electronic sensing and control to achieve the same regulatory function, thereby eliminating the source of mechanical wear associated with spring-flapper interactions.
2Ease of operation
If electromagnetic torque motor and flapper mechanisms are used, then fluid flow regulation is achieved, but mechanical wear leads to fluid contamination
Solution Approach 1:
The patent replaces the mechanical flapper-nozzle regulation mechanism with a piezoelectrically-actuated spool valve system. The piezoelectric actuator directly moves the spool to regulate flow, eliminating the flapper mechanism that causes wear and potential fluid contamination through particle generation.
3Measurement precision
If mechanical feedback springs are used to regulate spool valve, then position control is achieved, but moving parts increase device complexity
Solution Approach 1:
The patent replaces the mechanical feedback spring system with an electronic position sensing and control system. Sensors detect spool position and feed this information to a controller that adjusts the piezoelectric actuator accordingly, achieving precise control without mechanical feedback components.
Solution Approach 2:
The patent removes the feedback spring entirely from the system architecture. The mechanical feedback mechanism is completely extracted and replaced with an electronic control loop that uses sensors and a controller to achieve the same regulatory function without any moving feedback parts.
4Reliability
If piezoelectric bendable members are used to replace mechanical components, then mechanical wear is reduced, but the system requires independent flow regulation capability
Solution Approach 1:
The patent uses two independent piezoelectric bendable members, each controlling one side of the spool valve. This segmentation allows independent regulation of fluid flow to each side of the spool, providing precise flow control capability while maintaining a wear-free mechanical design.
Solution Approach 2:
The piezoelectric bendable members change their physical shape (bending) in response to electrical signals, altering the flow path geometry to regulate fluid flow. This parameter change approach enables flow regulation without mechanical moving parts that would wear.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution minimizes mechanical wear, enhances reliability, reduces fluid contamination risks, and maintains high bandwidth while being compact and low-power, capable of operating in high-g force and vibration environments without null bias and shift.
Implementation Method 1
a piezoelectric servo valve reduces mechanical wear and tear by removing the prior art torque motor, flapper, and feedback spring, and replacing with a pair of piezo bendable members
Data Source
AI summary
A piezoelectric ring bender servo valve assembly reduces mechanical wear by removing mechanical components used in prior art servo valves. The assembly does not use torque motor, flapper, and feedback spring. In this manner, no moving parts are required, which reduces maintenance and costs. A pair of piezoelectric ring benders mount adjacently to a pair of nozzles. The piezoelectric ring benders independently regulate the flow of fluid through the nozzles by moving between an open position to enable flowage, and a closed position to restrict flowage. A linear position sensing device measures and provides feedback about the spool position to a valve controller. The valve controller allows the spool valve to move until valve position achieves command position and the force on the spool valve is in equilibrium with pressure difference across spool valve. An H-bridge operable to switch the polarity of a differential pressure applied across to a load.