Composite Tube Bellow With Offset Holes for Compact Flexibility

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Solution Overview

Problem

Existing composite drive shafts and pipes face limitations in flexibility due to the stiffness of metallic bellows, which can lead to installation challenges in confined spaces and misalignment issues, and require additional weight and space with larger diameters or multiple bellows, which is undesirable in aerospace applications.

Innovation Solution

A composite tube design featuring a bellow with offset holes on either side, providing increased flexibility without increasing diameter or length, allowing for uniform material properties and reduced material stiffness, while maintaining torque transmission efficiency and allowing for higher operational velocities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the diameter of the bellow is increased to achieve greater flexibility, then the flexibility is improved, but the weight and space requirements increase

Engineering Contradiction:
ImproveflexibilityVSAvoidweight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The bellow is designed with a porous or honeycomb structure in the radial direction, creating multiple radial layers connected by radial walls. This porous architecture reduces material usage and weight while maintaining flexibility through the interconnected cellular structure that can deform during bending.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The bellow structure is segmented into multiple radial layers (first radial layer, second radial layer, etc.) separated by radial walls. This segmentation allows each layer to deform independently during flexing, providing flexibility without requiring a large overall diameter, thus reducing weight and space requirements.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If multiple bellows are used along the drive shaft to increase articulation, then the flexibility is improved, but the axial length increases

Engineering Contradiction:
ImprovearticulationVSAvoidaxial length
Core Design Contradiction:
Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The bellow is divided into multiple radial layers separated by radial walls, creating segmented regions that can articulate independently. This radial segmentation provides multiple articulation points within a compact axial length, eliminating the need for multiple separate bellow components along the shaft.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of increasing articulation by adding bellows along the axial dimension, the invention creates articulation in the radial dimension through multiple radial layers. This dimensional shift allows high articulation capability within a constrained axial length.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If a larger diameter bellow is used to provide flexibility, then the flexibility is improved, but the space requirements increase

Engineering Contradiction:
ImproveflexibilityVSAvoidspace
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The porous or honeycomb radial structure reduces the effective material volume while maintaining flexibility. The interconnected cells can deform during bending, providing flexibility without requiring a large external diameter, thus reducing space requirements in confined installations.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

Multiple radial layers segmented by radial walls allow the bellow to achieve flexibility through layered deformation rather than requiring a large single-diameter structure. This segmentation enables high flexibility within a compact radial envelope, reducing the space occupied.

Inventive Principle:
Principle #1Segmentation

4Adaptability or versatility

If material stiffness is reduced to increase flexibility, then the flexibility is improved, but the strength decreases

Engineering Contradiction:
ImproveflexibilityVSAvoidstrength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The porous or honeycomb structure reduces material stiffness to enable flexibility while maintaining structural integrity through the geometric configuration of the cellular walls. The radial walls and layered structure provide load-bearing pathways that preserve strength despite reduced material density.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The bellow utilizes composite construction with multiple radial layers and radial walls, potentially using different materials or material configurations in different regions. This composite approach allows optimization of flexibility in certain areas while maintaining strength in load-critical regions.

Inventive Principle:
Principle #40Composite materials

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 design enhances flexibility and reduces material strength impact, enabling the bellow to accommodate misalignments and facilitate installation in constrained spaces with reduced weight and cost, while maintaining high critical velocities and efficient torque transmission.

Implementation Method 1

each side of the bellow comprises at least one hole; wherein the at least one hole on the first side is offset in relation to the at least one hole on the second side

Methodology Applied
Scientific EffectMaterial removal:

Data Source

PatentEP4283143A1Composite tube
Publication Date: 2023.11.29 CROMPTON TECH GROUP
  • EP4283143A1 patent drawingFigure 1
  • EP4283143A1 patent drawingFigure 2
  • EP4283143A1 patent drawingFigure 3

AI summary

A composite tube (2) comprising a region of greater diameter forming a bellow (4). The bellow (4) has a first side (20) and a second side (21) spaced apart in the axial direction of the tube (3). Each side of the bellow (20, 21) comprises at least one hole (6, 7) and the at least one hole (6) on the first side (20) is offset in relation to the at least one hole (7) on the second side (21). The holes in the bellow provide increased flexibility, thereby allowing a greater amount of bending or articulation in the shaft. The holes reduce the amount of material in the sides of the bellow, thereby reducing the material stiffness and thereby increasing the flexibility. As the increased flexibility is provided in the sides of the bellow, the flexibility is achieved without increasing the diameter or axial length of the bellow. Axial length is kept to a minimum as a single bellow can provide the desired degree of flexibility rather than requiring the use of several bellows. This presents an advantage in applications where there is limited space or where added weight is undesirable.