Aircraft Rotor Flexible Coupling for Misalignment and Torque Transfer

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Solution Overview

Problem

Existing convertiplanes and helicopters face challenges in efficiently managing oscillations and misalignments of rotor components due to aerodynamic and gyroscopic forces, requiring complex and heavy homokinetic joints that are not optimized for weight and simplicity.

Innovation Solution

The use of corrugated, elastic flexible joints made of fibre-reinforced laminate or composite materials to allow oscillations and misalignments between rotor components, providing homokinetic transmission without articulated components, ensuring high torsional rigidity and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If homokinetic articulated joints with multiple rigid elements are used to allow oscillation between hub and control shaft, then torque transmission capability is improved, but device complexity and weight increase

Engineering Contradiction:

Improvetorque transmission capabilityVSAvoidnumber of articulated components

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The joint changes from a rigid multi-component structure to a flexible single-component structure made of elastomeric material, allowing oscillation through material deformation rather than mechanical articulation. This maintains torque transmission while reducing complexity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The joint uses composite elastomeric material that combines flexibility for oscillation with sufficient strength for torque transmission, eliminating the need for multiple rigid articulated components while maintaining both oscillation capability and torque capacity.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If homokinetic articulated joints with multiple rigid elements are used to accommodate misalignment between hub and control shaft, then misalignment tolerance is improved, but weight increases

Engineering Contradiction:

Improvemisalignment toleranceVSAvoidjoint weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The joint uses material elasticity rather than rigid mechanical components to accommodate misalignment, allowing the elastomeric material to deform and absorb angular deviations without requiring heavy articulated structures.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical articulated joint system with a flexible elastomeric coupling that uses material deformation to accommodate misalignment, eliminating the need for complex rigid component assemblies and reducing weight.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If simplified joint design with fewer components is used, then ease of manufacture is improved, but torque transmission capability may deteriorate

Engineering Contradiction:

Improvenumber of componentsVSAvoidtorque transmission capability

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The elastomeric joint uses composite material formulation that provides both flexibility for oscillation and sufficient strength for torque transmission, achieving simplified single-component design without sacrificing torque capacity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The joint design changes from rigid components to flexible elastomeric material with optimized physical parameters, allowing a single component to simultaneously provide oscillation capability and torque transmission that previously required multiple articulated parts.

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 solution simplifies the rotor structure, reduces weight, and maintains efficient torque transmission while accommodating variable oscillations and misalignments, enhancing the convertiplane's operational flexibility and reducing construction complexity.

Implementation Method 1

The joint according to the invention is flexible and, in particular, is defined by at least one corrugated element made of elastically deformable material

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

corrugated, elastic flexible joints made of fibre-reinforced laminate or composite materials to allow oscillations and misalignments between rotor components, providing homokinetic transmission without articulated components, ensuring high torsional rigidity and flexibility

Methodology Applied

Scientific EffectComposite materials: Composite Materials

Data Source

PatentUS12434824B2Rotor for an aircraft capable of hovering

Publication Date: 2025.10.07 LEONARDO SPA

AI summary

A rotor for an aircraft is described, comprising an input shaft rotatable around a first axis; an output member rotatable around a second axis; a coupling element functionally interposed between the input shaft and the output member and adapted to transmit the motion from the input shaft to the output member; the coupling element is configured to allow, in use, a fixed or variable inclination between the respective first and second axes; the coupling element comprises at least a first corrugated element made of an elastically deformable material; the first corrugated element allows the inclination through elastic deformation.