Eccentric Crankshaft Assembly for Aircraft Flap Actuation
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Solution Overview
Problem
Existing aircraft flap actuation mechanisms face clearance issues and mechanical inefficiencies, preventing over-center rotation and requiring suboptimal actuator loads.
Innovation Solution
A crankshaft assembly eccentrically mounted between cylindrical supports, coupled with a coupler link, allows 360° over-center rotation, translating the coupler link between retracted and deployed positions with a single direction of rotary actuator rotation, reducing motor torque requirements and avoiding over-center interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional crank arm mechanism is used to deploy flaps, then the mechanism can achieve flap deployment, but it cannot drive the crank arm over-center due to clearance issues and mechanical interference
Solution Approach 1:
The mechanism is divided into separate functional components: a crankshaft assembly with eccentric journal that can rotate independently, a coupler link that transmits motion, and a carrier beam that rotates the flap. This segmentation allows the crankshaft to rotate through 360 degrees without interference from other components, as each segment is designed to accommodate the motion of others.
Solution Approach 2:
The mechanism transitions from a planar two-dimensional motion to a three-dimensional spatial arrangement. The crankshaft rotates about an axis perpendicular to the plane of the coupler link and carrier beam, allowing over-center rotation by utilizing the third dimension. The eccentric journal position offset from the crankshaft center creates a spatial configuration that enables full rotation without mechanical interference.
2Productivity
If a conventional crank arm mechanism is used, then flap deployment is achieved, but mechanical inefficiency and suboptimal actuator loads are present
Solution Approach 1:
The mechanism changes the geometric parameters of the motion transmission path. By positioning the coupler link at an optimized angle relative to the carrier beam and crankshaft, the mechanical advantage is improved. The eccentric journal position and coupler link length are specific parameters that can be adjusted to optimize the actuator load and mechanical efficiency throughout the flap deployment range.
Solution Approach 2:
The mechanism allows dynamic adjustment of the transmission path geometry during operation. As the crankshaft rotates through its 360-degree range, the angles and relative positions of the coupler link and carrier beam continuously change, optimizing the mechanical advantage at different points in the flap deployment cycle. This dynamic configuration maintains more favorable actuator loads compared to fixed-geometry mechanisms.
3Ease of operation
If the crankshaft assembly with eccentric journal is used, then 360° over-center rotation is achieved, but the device complexity increases compared to conventional mechanisms
Solution Approach 1:
The crankshaft assembly with eccentric journal performs multiple functions: it provides the rotating motion drive, establishes the transmission path geometry, and enables over-center rotation capability. The coupler link simultaneously connects the crankshaft to the carrier beam while maintaining optimized angular relationships. This multi-functionality reduces the need for additional specialized components that would increase complexity.
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
This configuration enables efficient deployment and retraction of flaps with a smaller actuation mechanism footprint and reduced motor torque, overcoming previous inefficiencies and interference issues.
Implementation Method 1
A crankshaft assembly having a crankshaft eccentrically mounted between cylindrical supports is rotated in a first direction about a rotational axis. A coupler link rotatably engaged to the crankshaft and pivotally engaged to a carrier beam with an attached flap, is translated as the crankshaft is eccentrically rotated about the axis
Data Source
AI summary
A flap support mechanism includes a carrier beam on which a flap is mounted. The carrier beam is rotatably mounted to a flap support for rotation relative to a wing. A crankshaft assembly is rotatable about an axis and has a crankshaft eccentrically extending between an inboard cylindrical support and an outboard cylindrical support. A coupler link is rotatably engaged to the crankshaft and pivotally connected to the carrier beam. Rotation of the crankshaft from a first eccentric position to a second eccentric position translates the coupler link between a retracted position and a deployed position.