Aircraft Structure Joint for Large-Engine Wing Clearance
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Solution Overview
Problem
Conventional engine mounting pylons with low hyperstaticity are not suitable for large diameter engines, as they require a significant vertical distance between the engine and the wing to accommodate thrust loads and movement, limiting their use in aircraft with Ultra High-Bypass Ratio engines.
Innovation Solution
A joint design allowing relative rotation and translational movement along a specific axis while preventing movement orthogonal to it, using a bracket, pin, and part-spherical bearing surfaces to connect aircraft structures, enabling close coupling and load distribution for large engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional couplings are used to connect engine mounting pylon to wing box, then thrust loads can be transmitted and freedom of movement is allowed, but the vertical distance between engine and wing must be significant
Solution Approach 1:
The patent employs a spherical bearing interface where a spherical portion of the pylon engages with a corresponding spherical bearing in the wing box. This curved surface contact allows rotational movement and accommodates misalignment while maintaining a compact vertical profile, eliminating the need for long vertical couplings.
Solution Approach 2:
The joint design incorporates dynamic capabilities through the spherical bearing that permits rotation and the ability to accommodate thermal expansion and structural deformation. The pylon can rotate relative to the wing box within the spherical bearing, providing freedom of movement without requiring excessive vertical clearance.
2Adaptability or versatility
If engine mounting pylon is designed for large diameter engines, then engine clearance is improved, but the vertical distance requirement increases
Solution Approach 1:
The spherical bearing interface enables the pylon to accommodate large diameter engines by providing rotational freedom and alignment tolerance, while maintaining a compact vertical structure. The curved contact surface allows the pylon to self-align with the wing box, reducing the vertical space required compared to conventional rigid couplings.
3Device complexity
If conventional statically determined interface is used, then structure is simple, but it cannot accommodate very large diameter engines
Solution Approach 1:
The spherical bearing interface provides a compact yet highly adaptable connection that can accommodate very large diameter engines. The curved surface geometry allows for rotational movement and thermal expansion while maintaining structural integrity, achieving high adaptability without significantly increasing interface complexity.
Solution Approach 2:
The joint transforms the static interface into a dynamic one by allowing rotation within the spherical bearing. This dynamic capability enables the structure to accommodate large diameter engines and their associated thermal and mechanical loads while maintaining a relatively simple overall interface design.
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 design reduces the vertical distance between the engine and wing, allowing for very close coupling and efficient load distribution, accommodating engine movement and simplifying aircraft construction by enabling installation without opening the pylon or wing box.
Implementation Method 1
The convex part-spherical outer bearing surface is disposed on the first end of the pin and is configured for rotational sliding contact with a concave part-spherical bearing surface disposed in the opening
Implementation Method 2
The pin is configured to translate along the first axis relative to the part-spherical outer bearing surface and/or relative to the second aircraft structure
Data Source
AI summary
A joint for connecting a first aircraft structure to a second aircraft structure such that relative rotation and relative translational movement of the first and second aircraft structures along a first axis is permitted, whilst relative translational movement of the first and second aircraft structures along axes orthogonal to the first axis is substantially prevented. The joint includes a bracket having an opening aligned with the first axis; a pin aligned with the first axis and extending through the opening; and a bearing mounted in the opening. The bearing has an inner bearing surface defining a bore through which the pin extends, which is configured for translational sliding contact with the pin, and a part-spherical outer bearing surface configured for rotational sliding contact with the opening.