Compliant Bushing Channel Structure for Leak-Resistant Installation

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Solution Overview

Problem

Conventional bushings face challenges in balancing installation ease with leakage prevention, as tight clearances hinder installation while split designs introduce unwanted leakage paths.

Innovation Solution

The design incorporates a compliant bushing with specific channel geometries that provide axial and hoop direction compliance without full-length splits, featuring channels that terminate short of ends and have varying angles and widths, allowing for tailored stiffness and thermal response while minimizing leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tight clearance is used between bushing and shaft, then leakage resistance is improved, but installation difficulty increases

Engineering Contradiction:
Improveleakage resistanceVSAvoidinstallation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The bushing is divided into multiple segments along its length, creating gaps between adjacent segments. These gaps allow the bushing to be compressed and installed over the shaft more easily, while the segments remain closely spaced to prevent leakage. The segmentation principle resolves the contradiction by providing installation compliance without creating continuous leakage paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the bushing have different clearance characteristics. The gaps between segments provide local compliance for installation, while the regions between gaps maintain tight clearances for leakage prevention. This local differentiation of quality allows the bushing to satisfy both installation ease and leakage resistance requirements in different locations.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If split design is used through entire length of bushing, then installation ease is improved, but leakage risk increases

Engineering Contradiction:
Improveinstallation easeVSAvoidleakage resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Instead of a single continuous split through the entire length, the bushing is segmented into multiple discrete sections. This creates multiple small gaps rather than one large continuous gap, providing installation compliance while significantly reducing the leakage path area and preventing through-leakage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The split is applied partially rather than completely - gaps exist between segments but the segments extend far enough along the bushing length to maintain structural integrity and prevent leakage. This partial application of the split principle provides sufficient installation ease without excessive leakage risk.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If compliance is increased for installation, then installation ease is improved, but leakage paths are introduced

Engineering Contradiction:
Improveinstallation easeVSAvoidleakage resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The compliance needed for installation is achieved through segmentation into discrete sections with small gaps, rather than through continuous splitting. This provides the necessary flexibility for installation while maintaining enough material between segments to block leakage paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bushing segments act as flexible elements that can compress during installation, similar to flexible shells. The segments deform elastically to accommodate installation requirements while maintaining their structural integrity to prevent leakage, embodying the flexible shell principle.

Inventive Principle:
Principle #30Flexible shells and thin films

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 approach facilitates easier installation with reduced tooling and cost, comparable to solid bushings in terms of leakage resistance, and better than split bushings, by maintaining compliance without introducing additional leakage paths.

Implementation Method 1

a first plurality of channels (86) extending from the first end (76) towards the second end (78); and a second plurality of channels (88) extending from the second end (78) towards the first end (76)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4215768B1Leak resistant compliant bushing
Publication Date: 2024.11.13 HAMILTON SUNDSTRAND CORP
  • EP4215768B1 patent drawingFigure 1~2
  • EP4215768B1 patent drawingFigure 3~4
  • EP4215768B1 patent drawingFigure 5~6

AI summary

A leak resistant compliant bushing (64) includes a body (74) having a first end (76), a second end (78), an outer surface (80) and an inner surface (82) defining a passage. The outer surface (80) and the inner surface (82) extending between the first end (76) and the second end (78) and define an axial axis (B). A first plurality of channels (86) extends into the body (74) from the first end (76). Each of the first plurality of channels (86) includes a terminal end (90) that is spaced from the second end (78). A second plurality of channels (88) extend into the body (74) from the second end (78). Each of the second plurality of channels (88) extend between adjacent ones of the first plurality of channels (86) and include a terminal end section (92) that is spaced from the first end (76).