Aircraft Flap Actuation System with Angled Crank Shaft
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Solution Overview
Problem
Actuating flaps on aircraft wings in a streamwise direction efficiently, simply, and lightweightly is challenging, especially with modern commercial aircraft having swept and thin wings.
Innovation Solution
A geared rotary actuator system with a drive gear and crank shaft, where the crank shaft is rotated by the drive gear about a second rotational axis angled relative to the first, allowing the crank arm to move the flap in the streamwise direction, facilitating efficient and compact flap actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional flap actuation systems are used, then flap actuation is achieved, but the system becomes heavy and complex
Solution Approach 1:
The patent combines the rotary actuator, crank mechanism, and flap linkage into an integrated assembly where components share structural elements and mounting points. The actuator housing serves as a structural component, and the crank mechanism is directly coupled to the actuator output, eliminating the need for separate coupling devices and reducing overall system weight and complexity.
Solution Approach 2:
The actuator assembly is designed to perform multiple functions: the rotary actuator provides both the driving torque and structural support, the crank mechanism simultaneously converts rotary motion to reciprocating motion and provides mechanical advantage, and the linkage system handles both force transmission and geometric constraints. This multi-functionality reduces the number of dedicated components needed.
2Volume of moving object
If traditional actuation mechanisms are used, then flap motion is achieved, but the system does not fit within thin modern aircraft wings
Solution Approach 1:
The patent nests components within each other to minimize the overall envelope of the actuation system. The crank mechanism is positioned within the actuator housing, and the linkage components are arranged to fit within the available space in the wing cross-section. This nesting allows the system to fit within the thin profile of modern aircraft wings while maintaining full actuation functionality.
Solution Approach 2:
The patent utilizes the spanwise dimension of the wing to arrange actuation components, rather than only using the chordwise dimension. By orienting the crank mechanism and linkage along the spanwise direction and leveraging the wing's thickness in the lateral dimension, the system achieves compact packaging that fits within the three-dimensional space available in thin wings.
3Device complexity
If simple actuation linkages are used, then system complexity is reduced, but power transfer efficiency decreases
Solution Approach 1:
The patent employs a dynamic crank mechanism that adjusts the mechanical advantage ratio throughout the flap travel range. As the flap moves through different positions, the crank geometry automatically provides optimal force multiplication, ensuring efficient power transfer across the entire range of motion without requiring complex variable geometry linkages or multiple actuators.
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
Enables efficient actuation of flaps in the streamwise direction with significant Fowler motion range, reducing weight and complexity, while fitting within the thin wings of modern aircraft, and simplifying power transfer.
Implementation Method 1
a driven gear of a crank shaft in gear meshing engagement with the drive gear of the geared rotary actuator to rotate the crank shaft about a second rotational axis
Data Source
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AI summary
Disclosed herein is a system for actuating a flap coupled to a wing of an aircraft in a streamwise direction. The system comprises a geared rotary actuator comprising a drive gear that is rotatable about a first rotational axis. The system also comprises a crank shaft comprising a driven gear in gear meshing engagement with the drive gear of the geared rotary actuator to rotate the crank shaft about a second rotational axis. The second rotational axis is angled relative to the first rotational axis. The system further comprises a crank arm co-rotatably coupled to the crank shaft and configured to be coupled to the flap. Rotation of the crank shaft about the second rotational axis rotates the crank arm in a direction perpendicular to the second rotational axis.