Flexible Diaphragm Coupling Axial Force Tolerance

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Solution Overview

Problem

Aerospace shaft coupling applications require a flexible diaphragm coupling that can tolerate both linear and nonlinear deflections caused by axial force loading, which existing designs fail to accommodate due to the absence of consideration for cubic non-linear membrane stresses.

Innovation Solution

A flexible diaphragm coupling with a radially inner hub portion, a radially outer rim portion, and a diaphragm portion that tapers from maximum axial thickness near the hub to minimum thickness near the rim, optimized to manage stress distribution from linear and cubic non-linear restorative spring forces, featuring a contoured and planar surface configuration and integral formation with additional flexible elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the diaphragm is made thinner at the center to reduce bending stress from axial deflection, then bending stress is minimized, but the diaphragm cannot tolerate cubic non-linear membrane stresses from axial force loading

Engineering Contradiction:
Improvebending stressVSAvoidaxial force tolerance
Core Design Contradiction:
Stress or pressureVSStrength

Solution Approach 1:

The diaphragm is designed with non-uniform thickness distribution, being thinnest at the center and thicker toward the hub and rim. This local variation in thickness allows different regions to handle different stress types: the thin center reduces bending stress while the thicker edges provide strength for axial force tolerance

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The diaphragm profile is asymmetric with respect to thickness distribution, creating a specific geometric configuration where the point of minimum thickness is positioned to optimize the balance between bending stress reduction and axial force tolerance, accommodating both linear and cubic non-linear stress distributions

Inventive Principle:
Principle #4Asymmetry

2Ease of operation

If the diaphragm is designed for linear axial spring rate only, then simple restorative force is achieved, but nonlinear deflections from axial force loading cannot be tolerated

Engineering Contradiction:
Improverestorative force simplicityVSAvoiddeflection tolerance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The diaphragm's geometric parameters, particularly its thickness distribution and contour profile, are specifically optimized to accommodate both linear and cubic non-linear stress distributions. This allows the diaphragm to provide simple restorative force while reliably tolerating nonlinear deflections under axial force loading

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the diaphragm thickness is uniform, then manufacturing is simplified, but stress distribution under axial loading is not optimized

Engineering Contradiction:
Improvediaphragm fabricationVSAvoidstress distribution
Core Design Contradiction:
Ease of manufactureVSStress or pressure

Solution Approach 1:

Rather than uniform thickness, the diaphragm employs local quality variation with specific thickness at different locations optimized for stress distribution under axial loading, while still maintaining manufacturability through defined geometric parameters

Inventive Principle:
Principle #3Local quality

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 novel diaphragm coupling effectively accommodates axial force loads and stress distributions, enhancing stiffness and torque transmission while maintaining buckling stability, with improved deflection tolerance and reduced material stress.

Implementation Method 1

a flexible diaphragm portion that extends between the radially outer rim portion and the radially inner hub portion. The flexible diaphragm portion includes a radially inner diaphragm section having a maximum axial thickness adjacent the radially inner hub portion and a radially outwardly tapering axial thickness extending to a point of minimum axial thickness

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the geometric configuration of the diaphragm coupling of the subject invention is optimized to accommodate the stress distribution associated with linear and cubic non-linear restorative spring forces generated by an axially applied load

Methodology Applied
Scientific EffectMembrane stress:

Data Source

PatentEP2568190B1Flexible diaphragm coupling for axial force loading
Publication Date: 2014.10.22 GOODRICH CORP
  • EP2568190B1 patent drawingFigure 1
  • EP2568190B1 patent drawingFigure 2

AI summary

A flexible diaphragm coupling is disclosed which includes a radially inner hub portion (12), a radially outer rim portion (14), and a flexible diaphragm portion (16) extending between the radially outer rim portion and the radially inner hub portion. The flexible diaphragm portion includes a radially inner diaphragm section (18) having a maximum axial thickness (TBF) adjacent the radially inner hub portion and a radially outwardly tapering axial thickness extending to a point of minimum axial thickness (Tmin) of the diaphragm portion, and a radially outer diaphragm section (20) having a maximum axial thickness (TA)adjacent the radially outer rim portion and a radially inwardly tapering axial thickness extending to the point of minimum axial thickness of the diaphragm portion. By design, the point of minimum axial thickness of the diaphragm portion is closer to the radially outer rim portion than to the radially inner hub portion.