Electromechanical Actuator Synchronizer for Spoiler Droop
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Solution Overview
Problem
Existing electromechanical actuators (EMAs) lack the capability to lower spoilers below their neutral position, which is essential for high-lift situations and closing air gaps between spoilers and wing flaps.
Innovation Solution
The development of an electromechanical actuator (EMA) with a droop function, featuring a housing, motor, sun gear, ratchet, torque limiter, synchronizer, solenoid, and spring, allowing the actuator to move the output in both positive and negative quadrants, including below the neutral position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the EMA is designed with anti-extension mode to prevent rotation in positive quadrant, then safety is improved, but the ability to move output in negative quadrant is restricted
Solution Approach 1:
The synchronizer dynamically changes the connection state between the output shaft and ratchet based on the output position. In the negative quadrant, the synchronizer automatically disengages, disconnecting the ratchet from the output shaft, allowing bidirectional rotation. In the positive quadrant, the synchronizer engages to enable anti-extension mode. This dynamic switching resolves the contradiction by adapting the system's constraints to the operational quadrant.
Solution Approach 2:
The synchronizer acts as an intermediary mechanism between the output shaft and ratchet. It mediates the torque transmission by selectively engaging or disengaging based on the output position. When disengaged in the negative quadrant, it allows free rotation; when engaged in the positive quadrant, it enables the ratchet to prevent rotation. This intermediary component resolves the contradiction by controlling the coupling state between drive and load.
2Reliability
If the ratchet is connected to the output shaft to provide anti-extension capability, then safety is improved, but the device complexity increases
Solution Approach 1:
The synchronizer serves multiple functions: it acts as a clutch to engage/disengage the ratchet, it determines the operational quadrant, and it controls the anti-extension capability. By making this single component multi-functional, the patent avoids adding separate mechanisms for each function, thereby limiting the increase in device complexity while still providing the required safety and adaptability.
3Ease of operation
If the solenoid is used to control synchronizer engagement, then ease of operation is improved, but the device complexity increases
Solution Approach 1:
The spring-loaded cam mechanism automatically positions the floating frame based on the output position, causing the synchronizer to engage or disengage without requiring external control signals. The system self-regulates the anti-extension mode based on the quadrant, with the solenoid only needed to override this automatic behavior when active mode is required. This self-service approach minimizes the need for complex control systems.
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 EMA effectively provides a droop function, enabling the actuator to lower spoilers below the neutral position, enhancing its operational capabilities in high-lift situations and maintaining system safety by automatically disengaging anti-extension mode in the negative quadrant.
Implementation Method 1
a solenoid mounted to a floating frame within the housing and connected to the second conical portion, the solenoid configured to pull the second conical portion along the axis away from the first conical portion when the solenoid is energised
Implementation Method 2
a spring arranged to bias the frame along the axis away from the first conical portion
Implementation Method 3
a synchroniser comprising a first conical portion connected to an end of the output shaft, and a second conical portion connected to the ratchet wheel, wherein the synchroniser has an engaged position in which rotation of the first conical portion is transmitted to the second conical portion
Data Source
AI summary
An electromechanical actuator, EMA, having a plurality of modes. The EMA includes a housing, a motor fixed relative to the housing, the motor having an output shaft, the output shaft defining an axis (X) of the EMA and a first sun gear connected for rotation with the output shaft. The system includes an output arranged to be driven by rotation of the first sun gear, wherein the output is arranged to have a neutral position and to be movable away from the neutral position within a positive quadrant and away from the neutral position within a negative quadrant and a ratchet comprising a ratchet wheel and a pawl. The system also has a torque limiter having a predetermined torque limit and arranged to limit torque transfer between the first sun gear and the output.