Nested Bushing Assembly for Independent Two-Axis Fastener Alignment
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Solution Overview
Problem
In rotary wing aircraft rotor systems, the use of large tolerances and oversized attachment holes leads to potential relative movement between components, requiring an adjustable yet rigid interface to translate bearing loads, but existing solutions either increase complexity and cost or fail to provide independent bi-directional adjustment.
Innovation Solution
A bushing assembly comprising a first and second bushing portion arranged coaxially, allowing independent adjustment about two perpendicular axes through rotation, with features such as nesting and offset openings to align fasteners effectively, reducing misalignment and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If oversized attachment holes are formed to ensure alignment between components, then alignment is improved, but relative movement between components occurs
Solution Approach 1:
The bushing assembly employs nested bushings where an inner bushing is positioned within an outer bushing. The inner bushing defines a first opening for alignment while the outer bushing provides structural support and load translation. This nested configuration allows precise alignment through the inner bushing's opening while the outer bushing maintains component stability and prevents relative movement through proper fit and load distribution.
Solution Approach 2:
The bushing assembly acts as an intermediary component between adjacent rotor components. It provides a rigid interface that translates bearing loads while maintaining precise alignment. The bushing's opening accommodates fasteners for accurate alignment, while the bushing material and structure prevent undesirable relative movement, effectively mediating between the requirements for alignment precision and movement restriction.
2Adaptability or versatility
If two separate eccentric bushings are used to allow independent adjustment in two directions, then adjustability is improved, but complexity and cost increase
Solution Approach 1:
The invention merges the functionality of two separate eccentric bushings into a single integrated bushing assembly. The outer bushing and inner bushing work together as a unified structure where the inner bushing can rotate independently within the outer bushing. This allows independent adjustment in two perpendicular directions through the rotation of the inner bushing, while maintaining a simpler, more cost-effective single assembly rather than requiring two separate adjustable components.
Solution Approach 2:
The bushing assembly incorporates dynamic adjustability where the inner bushing can be rotated to different angular positions within the outer bushing. This rotational degree of freedom enables independent adjustment in two perpendicular directions. The dynamic capability is achieved through a simple rotational mechanism rather than complex multi-component adjustment systems, maintaining ease of adjustment while reducing overall complexity.
3Device complexity
If a single eccentric bushing is used, then complexity is reduced, but independent bi-directional adjustment is not provided
Solution Approach 1:
The bushing assembly is segmented into an outer bushing and an inner bushing that can rotate independently within the outer bushing. This segmentation allows the inner bushing to provide independent adjustment capability in two directions through rotation, while the outer bushing maintains structural integrity and load translation functionality. The segmented design achieves bi-directional adjustment without requiring two completely separate bushing assemblies.
Solution Approach 2:
The nested configuration of the inner bushing within the outer bushing provides independent adjustability. The inner bushing's rotation within the stationary outer bushing enables adjustment in two perpendicular directions. This nested arrangement achieves the functionality of independent bi-directional adjustment while maintaining a compact, integrated structure that is simpler than using two separate eccentric bushings.
Data Source
AI summary
A bushing assembly for receiving a fastener includes a first bushing portion and a second bushing portion arranged coaxially with the first bushing portion. The second bushing portion defines at least part of an opening for receiving the fastener. The second bushing portion is rotatable relative to the first bushing portion about an axis of rotation to adjust a position of the opening about a first axis and a second axis independently relative to the first bushing portion and the second bushing portion. The first axis is coplanar with and perpendicular to the second axis.