Nested Bushing Arrangement for Retention and Anti-Rotation

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Solution Overview

Problem

Typical bushing arrangements for short and narrow structural components face operational issues due to poor retention and rotation, especially when multiple bushings with small engaged lengths are used, leading to loosening over time.

Innovation Solution

A nested bushing arrangement is introduced, comprising a first and second bushing with specific geometric configurations and greasing grooves, where the tubular portions of each bushing are partially engaged to prevent rotation and press-fitted into a member, enhancing retention and allowing for greasing, and can be additively manufactured for complex designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple bushings with small engaged lengths are used to provide grease to lugs, then greasing of pin-to-bushing interface is enabled, but bushing retention is poor and bushings come loose during operation

Engineering Contradiction:

Improvegreasing capabilityVSAvoidbushing retention

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent employs nested bushings where a first bushing is positioned within a second bushing, creating overlapping engaged lengths. This nesting arrangement allows grease to be distributed to multiple lugs while each bushing benefits from extended retention length through the overlap region, simultaneously achieving greasing capability and improved retention.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention transitions from a single-bushing linear arrangement to a nested multi-dimensional configuration. By stacking bushings in a nested pattern with overlapping engaged lengths, the solution adds a dimensional aspect to the bushing arrangement, enabling both grease distribution to multiple lugs and enhanced retention through the overlapping regions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Length of moving object

If small engaged lengths are used in bushings, then installation in short structural components is feasible, but rotation of bushings occurs during operation

Engineering Contradiction:

Improvebushing engaged lengthVSAvoidbushing rotational stability

Core Design Contradiction:

Length of moving objectVSStability of the object's composition

Solution Approach 1:

The nested configuration allows bushings to be arranged concentrically with overlapping engaged lengths. This nesting provides rotational stability through the overlap region where bushings interlock, while still accommodating short structural component dimensions by utilizing the nested spatial arrangement rather than requiring a single long engaged length.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes bushings made from composite materials with varying hardness levels. The nested arrangement combined with composite material properties enhances rotational stability through differential wear characteristics and interlocking mechanisms in the overlap region, preventing rotation while maintaining compatibility with short component lengths.

Inventive Principle:

Principle #40Composite materials

3Ease of operation

If multiple separate bushings are used for greasing, then grease distribution to lugs is achieved, but the arrangement becomes complex and difficult to install

Engineering Contradiction:

Improvegrease distributionVSAvoidbushing arrangement complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges multiple bushing functions into a nested arrangement where bushings are positioned concentrically. This combining approach enables grease distribution to multiple lugs through the nested structure while simplifying installation compared to separate bushing arrangements, as the nested configuration can be installed as an integrated unit with overlapping engaged lengths providing automatic alignment.

Inventive Principle:

Principle #5Merging (Combining)

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 nested bushing arrangement increases retention length, prevents rotation of bushings, and allows for effective greasing, addressing the issues of loosening and poor retention in short and narrow structural components, such as in nose landing gear components.

Implementation Method 1

using either a press fit or shrink fit installation process

Methodology Applied

Scientific EffectPress fit:

Implementation Method 2

using either a press fit or shrink fit installation process

Methodology Applied

Scientific EffectShrink fit: Thermal Contraction

Data Source

PatentEP3342704B1Nested bushing arrangement

Publication Date: 2020.11.25 GOODRICH CORP

Figure 1A~1B
Figure 1C~1D
Figure 2

AI summary

A nested bushing arrangement is provided. The nested bushing arrangement may maximize bushing retention length in a narrow and/or small joint, and may offer anti-rotation features in the event that the nested bushing arrangement becomes loose. The nested bushing arrangement may comprise a first nested bushing (210) coupled to a second nested bushing (230). Each nested bushing may comprise a mating aperture located opposite an annulus body. The annulus body of each nested bushing may insert within the mating aperture of the opposite nested bushing to couple the first nested bushing to the second nested bushing.