Flexible Coupling with Diaphragms and Wedging Backup

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Solution Overview

Problem

Current flexible coupling means for rotating mechanical components, such as those in rotorcraft turbine engines, face challenges in tolerating axial and angular misalignments without compromising torque transmission integrity, particularly when diaphragms rupture or connections fail, leading to potential imbalance and increased wear.

Innovation Solution

A coupling system with a first and second member, each equipped with a diaphragm, featuring a complementary torque transmission device with protuberances and bearing faces having double inclinations, allowing for axial and radial misalignments while ensuring continuous torque transmission through wedging and centering mechanisms, even in emergency modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If thin flexible diaphragms are used to allow axial and angular misalignments, then the coupling means can tolerate misalignment between rotating members, but the diaphragms become fragile and susceptible to rupture under extreme conditions

Engineering Contradiction:
Improvemisalignment toleranceVSAvoiddiaphragm strength
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The coupling means is divided into two independent torque transmission paths: the primary path through flexible diaphragms and a secondary backup path through protrusions and grooves. This segmentation allows the diaphragms to handle normal misalignments while the backup mechanism provides reliability protection against rupture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The backup torque transmission device with protrusions and grooves is pre-installed and positioned to engage automatically when diaphragms rupture or fail. This beforehand preparation ensures continuous torque transmission without interruption, cushioning against the harmful effect of diaphragm rupture.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If a backup torque transmission device is added to prevent rupture consequences, then reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvetorque transmission continuityVSAvoidcoupling structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The backup torque transmission device is merged with the primary diaphragm coupling structure, sharing the same housing and alignment features. The protrusions and grooves are integrated into the existing coupling members, eliminating the need for separate backup mechanisms and reducing overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coupling members serve dual functions: the diaphragms provide flexible torque transmission and misalignment accommodation during normal operation, while the same coupling members with integrated protrusions and grooves provide backup torque transmission when diaphragms fail. This multi-functionality reduces the need for additional dedicated backup components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If protuberances and bearing faces with double inclinations are used for backup torque transmission, then continuous torque transmission is ensured, but manufacturing precision requirements increase

Engineering Contradiction:
Improveemergency mode operationVSAvoidface inclination accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The double inclination faces of the protuberances and bearing faces are designed to self-align and self-center during engagement. The geometric configuration automatically establishes the correct orientation and positioning when the backup mechanism activates, eliminating the need for high-precision manual alignment and reducing manufacturing complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The double inclination faces use asymmetric angles optimized for the specific engagement conditions. The first and second inclinations are differently angled to accommodate the directional forces and misalignments that occur during emergency operation, providing reliable torque transmission while being tolerant of manufacturing variations.

Inventive Principle:
Principle #4Asymmetry

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 system effectively maintains torque transmission and alignment between rotating members, minimizing the risk of rupture and wear by allowing controlled misalignments and self-locking connections, thus ensuring continuous operation and reducing mechanical stress.

Implementation Method 1

Each annular member comprises a thin flexible annular disc extending radially from a base towards an outer periphery... The flexibility of the diaphragms allows the coupling mechanism to tolerate an axial and/or angular offset

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

each protuberance having at least one face with double inclinations called 'face sliding' facing a face with double inclinations of an abutment called 'first bearing face'... The first inclination makes it possible, following a relative rotation of the protuberances with respect to the faces, to move axially the protuberances with respect to the faces

Methodology Applied
Scientific EffectWedging: Wedge

Implementation Method 3

The second inclination makes it possible... to generate radial forces on the protuberances, these radial forces being illustrated by arrows F3. The coupling means comprising several protuberances, the radial forces make it possible to center the first member with respect to the second member

Methodology Applied
Scientific EffectForce balance: Force

Data Source

PatentEP3130815B1Flexible coupling means, a mechanical transmission, and an aircraft
Publication Date: 2017.12.13 EUROCOPTER FRANCE SA
  • EP3130815B1 patent drawingFigure 1~2
  • EP3130815B1 patent drawingFigure 3~4
  • EP3130815B1 patent drawingFigure 5~6

AI summary

The present invention relates to a coupling means (10) having a first member (20) provided with a first diaphragm (22) and a second member (30) provided with a second diaphragm (32). The coupling means (10) includes a complementary device (40) comprising a plurality of protrusions (50) distributed circumferentially on a first cylinder (21) of the first member (20) and a plurality of stops (60) distributed circumferentially on a second cylinder (31) of the second member (30), each protrusion (50) having at least one sliding face (51) opposite a first bearing face (61) of a stop (60), each protrusion (50) having a blocking face (52) opposite a face called the "second bearing face (62)" of the second member (30).