Electromechanical Pitch Actuation System for Turbomachine Propellers
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Solution Overview
Problem
Current hydraulic pitch actuation systems for turbomachine propellers are complex, with stringent FHA requirements, challenges in ensuring the feathering function after pitch control failure, risk of actuator blocking, and inefficiencies in managing propeller rotation and pitch control, requiring redundant mechanical and hydraulic devices.
Innovation Solution
An electromechanical pitch actuation system using an electric motor-driven rotor and transmission screw with decoupling means, allowing translational movement of a nut to control blade pitch without inducing rotational movement, ensuring reliability through electrical redundancy and independent power circuits, and eliminating the need for additional devices to cover failures and overspeed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic system is used for pitch actuation, then the propeller pitch can be controlled, but the system becomes complex with multiple hydraulic components and requires redundancy for reliability
Solution Approach 1:
The patent replaces the hydraulic actuation system with an electromechanical actuator that uses an electric motor to drive a rotor and transmission screw mechanism. This substitution eliminates hydraulic fluid, pumps, valves, and associated components, thereby reducing system complexity while maintaining pitch control functionality and reliability through direct electromagnetic actuation
Solution Approach 2:
The patent extracts and removes the hydraulic system entirely from the pitch actuation mechanism. By eliminating the hydraulic fluid and associated hydraulic components (pumps, reservoirs, hoses, filters), the system achieves reduced complexity and potential failure points while the electromechanical actuator provides the necessary actuation force for pitch control
2Reliability
If additional mechanical and hydraulic systems are added to cover protective functions, then reliability against failures and overspeed is improved, but device complexity increases
Solution Approach 1:
The electromechanical actuator is designed to perform multiple functions including pitch control, feathering, and protective functions against overspeed and failures. The electric motor can be controlled to reverse rotation direction and adjust pitch angle in response to various failure conditions, eliminating the need for separate mechanical protective devices while maintaining comprehensive safety coverage
Solution Approach 2:
The patent combines multiple previously separate functions (pitch control, feathering, overspeed protection, failure protection) into a single integrated electromechanical actuator system. The control system manages all these functions through the same actuator, reducing the number of components while maintaining or improving overall system reliability
3Reliability
If counterweights are added to ensure feathering function after hydraulic failure, then feathering reliability is improved, but device complexity and weight increase
Solution Approach 1:
The patent replaces the mechanical counterweight system with an electromechanical feathering actuator. The electric motor can actively drive the blades to the feathered position (parallel to rotation axis) even after complete power loss or control failure, providing more reliable feathering without adding significant weight compared to large counterweights
4Ease of operation
If hydraulic lines and slides are used to transmit rotation, then pitch control is achieved, but the system requires additional components and potential failure points
Solution Approach 1:
The patent removes the hydraulic transmission system including lines, slides, and hydraulic actuators from the pitch control mechanism. The electromechanical actuator directly drives the transmission screw and nut mechanism, eliminating the need for hydraulic fluid transmission and associated components, thereby reducing complexity and potential leakage failure points
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 system provides a simpler, robust architecture that maintains pitch control and feathering functionality even in power loss or FADEC failure without additional devices, reducing the risk of actuator blocking and mechanical energy dependence, while minimizing size and power requirements.
Implementation Method 1
at least one electric motor driving a rotor about an axis
Implementation Method 2
a transmission screw driven in rotation about the axis by the rotor, a nut through which the transmission screw passes and cooperating with this screw so as to move in translation along the axis
Data Source
AI summary
A pitch actuation system for a turbomachine propeller, comprising an actuator with a movable portion configured to be connected to blades of the propeller in order to rotate them relative to the blade-pitch setting axes, wherein the actuator is an electromechanical actuator and comprises: blade-pitch control having a transmission screw rotated about an axis; a nut through which the transmission screw passes; and a member configured to engage with the blades in order to move the blades, wherein the nut is connected to the member via a decoupler configured such that a translational movement of the nut causes a translational movement of the member, but rotational movement of the member does not cause rotational movement of the nut.