Oblique-Link Torque Coupling for Rotary Misalignment

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Solution Overview

Problem

Existing couplings face challenges in accommodating misalignment between rotary components while maintaining dynamic stress resistance, low friction, and minimizing weight, particularly in aeronautical applications where precise axis alignment is difficult to achieve.

Innovation Solution

A coupling design featuring obliquely oriented links with compressive stress transfer capabilities, allowing for a significant degree of axial misalignment, utilizing materials with lower Young's modulus and higher thermal expansion coefficients to accommodate deformation and thermal growth, and optimized slant angles to minimize compressive stress density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the coupling accommodates significant misalignment between rotary components, then ease of assembly and adaptability improve, but dynamic stress resistance and friction control become more challenging

Engineering Contradiction:
Improvemisalignment toleranceVSAvoiddynamic stress resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the physical parameters of the link materials by selecting materials with lower Young's modulus and higher thermal expansion coefficients. This allows the links to deform more easily under misalignment conditions while maintaining stress resistance, effectively resolving the contradiction between adaptability and reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material selection for the links, combining materials that exhibit both lower Young's modulus for flexibility and higher thermal expansion coefficients for thermal accommodation. This composite approach enables the coupling to handle misalignment while maintaining dynamic stress resistance

Inventive Principle:
Principle #40Composite materials

2Reliability

If traditional coupling designs are used to ensure dynamic stress resistance, then reliability improves, but misalignment tolerance and ease of assembly deteriorate

Engineering Contradiction:
Improvedynamic stress resistanceVSAvoidease of assembly
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

By modifying material parameters (lower Young's modulus, higher thermal expansion), the links can accommodate assembly tolerances and misalignments without compromising stress resistance, thereby improving ease of assembly while maintaining reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The oblique link design introduces dynamic deformation capability, allowing the coupling to adapt to misalignment conditions during operation. This dynamic response enables easier assembly while maintaining reliable stress resistance throughout the operating envelope

Inventive Principle:
Principle #15Dynamics

3Strength

If oblique links with optimized slant angles are used to minimize compressive stress density, then stress resistance improves, but device complexity increases

Engineering Contradiction:
Improvecompressive stress resistanceVSAvoidlink geometry complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent optimizes the slant angle parameter of the oblique links to minimize compressive stress density. By carefully selecting this geometric parameter, the design achieves improved stress resistance while keeping the complexity increase manageable through a single primary geometric modification

Inventive Principle:
Principle #35Parameter changes

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 coupling effectively transfers torque while accommodating misalignment, reducing wear and allowing for easier assembly and disassembly, while maintaining low friction and weight efficiency.

Implementation Method 1

A plurality of circumferentially arranged links occupy the spacing, each link having an inner end connected to the outer face and an outer end connected to the inner face, the links being configured to work in compression during torque transfer

Methodology Applied
Scientific EffectCompressive stress: Compression

Implementation Method 2

utilizing materials with lower Young's modulus and higher thermal expansion coefficients to accommodate deformation and thermal growth

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

utilizing materials with lower Young's modulus and higher thermal expansion coefficients to accommodate deformation and thermal growth

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3971434B1Coupling and associated method of transferring torque
Publication Date: 2024.05.15 PRATT & WHITNEY CANADA CORP
  • EP3971434B1 patent drawingFigure 1
  • EP3971434B1 patent drawingFigure 2A
  • EP3971434B1 patent drawingFigure 2B

AI summary

The coupling (30) can have a female member (32) configured to rotate around an axis, defining an axial recess (36), and having a plurality of connections (52) circumferentially arranged along a radially inner face (38); a male member (34) extending inside the axial recess (36) concentrically to the female member (32) and having a plurality of connections (50) circumferentially arranged along a radially outer face (40); and a plurality of circumferentially arranged links (44), each link (44) having an inner end (46) engaged with a corresponding one of the male member connections (50), and an outer end (48) engaged with a corresponding female member connection (52), the links (44) being slanted off the radial orientation, with the inner end (46) being circumferentially offset from the outer end (48), the links (44) subjected to compression when transmitting torque between the female member (32) and male member (34).