Electromechanical Propeller Pitch Actuation System
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Solution Overview
Problem
Current hydraulic propeller pitch actuation systems in turboprop engines are complex, with issues related to strict redundancy requirements, feathering function after pitch control failure, risk of actuator locking, rotation offset, and additional mechanical and hydraulic devices needed for protection functions.
Innovation Solution
An electromechanical pitch actuation system using electric motors with a common rotor, transmission screw, and reduction gear, eliminating the need for hydraulic components and providing redundancy through electric motors and independent power supply, allowing continuous operation and feathering without additional devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic system is used for propeller pitch actuation, then the system can provide pitch control and emergency feathering functions, but the system complexity increases and requires additional components
Solution Approach 1:
The patent replaces the hydraulic actuation system with an electromechanical system using an electric motor directly coupled to a screw mechanism. This substitution eliminates hydraulic fluid, pumps, valves, and associated components, achieving the same pitch control and emergency feathering functions through electrical and mechanical means, thereby reducing system complexity while maintaining reliability
Solution Approach 2:
The patent extracts and removes the hydraulic system components (hydraulic fluid, hydraulic pump, hydraulic valves) from the actuation system, retaining only the essential electric motor and screw mechanism needed to achieve pitch control and emergency feathering, thus simplifying the overall system architecture
2Reliability
If redundancy systems are added to meet FHA requirements, then pitch control reliability improves, but device complexity increases
Solution Approach 1:
The patent merges the pitch control function and emergency feathering function into a single integrated electromechanical actuator. The electric motor provides continuous power for pitch control, while the screw mechanism inherently provides emergency feathering capability through its mechanical design, eliminating the need for separate redundant hydraulic systems and reducing overall complexity
Solution Approach 2:
The electromechanical actuator is designed to perform multiple functions: normal pitch control through electric motor operation and emergency feathering through the screw mechanism's mechanical properties. This multi-functionality eliminates the need for separate auxiliary systems, meeting FHA redundancy requirements without increasing device complexity
3Reliability
If counterweights are added to provide feathering function after hydraulic failure, then emergency feathering capability is ensured, but device complexity increases
Solution Approach 1:
The screw mechanism in the electromechanical actuator inherently provides emergency feathering capability through its own mechanical design. The screw threads and nut assembly automatically enable blade feathering when power is lost or during emergency conditions, without requiring external counterweights or additional auxiliary systems, thus achieving self-service emergency functionality
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 electromechanical system meets reliability requirements, reduces the risk of actuator locking, maintains pitch control during engine power loss, and eliminates the need for counterweights and additional protection devices, providing a simpler and more reliable propeller pitch control system.
Implementation Method 1
at least two electric motors for driving a common rotor
Implementation Method 2
a transmission screw rotated by the common rotor, the system further comprises a nut, through which the transmission screw passes and which is designed to cooperate with the blades so as to move them
Implementation Method 3
the common rotor is connected to the transmission screw by a reduction gear, the reduction gear comprising: a planetary shaft constrained to rotate with the common rotor; an external ring gear that surrounds the planetary shaft and is rigidly connected to a stator casing; and planet gears that mesh with the planetary shaft and the ring gear
Data Source
AI summary
A pitch actuation system for a turbine engine propeller, comprising an actuator, a movable part of which is designed to be connected to blades of the propeller so as to rotate said blades relative to blade pitch-setting axes, wherein the actuator is an electromechanical actuator and comprises at least two electric motors for driving a common rotor, and a transmission screw rotated by the common rotor, and in that the system further comprises a nut, through which the transmission screw passes and which is designed to cooperate with the blades so as to move them.