Back-to-Back Clutch Actuator for Variable Cowl Door Loads
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Solution Overview
Problem
Existing electro-mechanical actuator architectures for aircraft cowl doors face challenges due to high friction coefficients in frictional materials, which complicate the design and sizing for varied cowl door loads.
Innovation Solution
An electro-mechanical actuator architecture with a back-to-back clutch and no-back unit is designed, featuring skewed friction discs with adjustable skew angles to tailor torque capability, allowing for safe and controlled operation under different load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high friction coefficient materials are used in the clutch and no-back unit, then torque transmission capability is improved, but the design complexity and sizing difficulty increase
Solution Approach 1:
The patent applies parameter changes by varying the skew angles of friction discs in the clutch and no-back unit to optimize torque transmission. By adjusting the skew angle parameter, the design achieves adequate torque capability while simplifying the overall structure and reducing sizing complexity.
Solution Approach 2:
The patent employs dynamic design through adjustable skew angles that allow the friction discs to adapt to different load conditions. This dynamic parameter adjustment enables the actuator to handle varied cowl door loads without requiring an overly complex design.
2Reliability
If the actuator is designed to handle maximum cowl door loads, then reliability is improved, but the size and cost increase
Solution Approach 1:
The patent uses dynamic skew angle adjustment to enable the actuator to adapt to different load conditions. This allows a smaller, more compact actuator to reliably handle maximum cowl door loads by optimizing friction disc engagement based on actual operational requirements.
Solution Approach 2:
The patent applies local quality by varying the skew angles of specific friction discs within the clutch and no-back unit. This localized parameter optimization ensures reliable torque transmission under maximum load while keeping the overall actuator size reduced.
3Adaptability or versatility
If multiple friction discs with different skew angles are used, then adaptability to varied loads is improved, but manufacturing complexity increases
Solution Approach 1:
The patent manages manufacturing complexity by systematically varying the skew angle parameter across friction discs. This controlled parameter change provides adaptability to different loads while maintaining a standardized manufacturing approach that does not excessively complicate production.
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 architecture enables flexible sizing to accommodate various cowl door loads, reduces development time, prevents runaway failures, and offers cost advantages by optimizing torque capacity.
Implementation Method 1
a clutch (130) disposed on a first side (121) of the drive disc (120), the clutch (130) including a first friction disc (131) with a first skew angle (α1)... a no-back unit (140) disposed on a second side (122) of the drive disc (120), which is opposite the first side (121), the no-back unit (140) including a second friction disc (141) with a second skew angle (α2)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An electro-mechanical actuator architecture is provided for a cowl door (102) of an aircraft engine nacelle. The electro-mechanical actuator architecture includes a screw shaft (110), a drive disc (120) connected to the screw shaft, a clutch (130) disposed on a first side of the drive disc, the clutch including a first friction disc (131) with a first skew angle, and a no-back unit (140) disposed on a second side of the drive disc, which is opposite the first side, the no-back unit including a second friction disc (141) with a second skew angle, the first skew angle being higher than the second skew angle.