Aircraft Propulsion Coupling Layout for Transmission-Free Maintenance

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Solution Overview

Problem

Existing propulsion systems require frequent and cumbersome maintenance of coupling systems, necessitating the disassembly of the transmission system due to their integration within it, leading to increased downtime and costs.

Innovation Solution

The coupling systems are positioned outside the transmission system, allowing maintenance without disassembling it, with features like free wheels and splines facilitating accessibility and reducing friction-induced pollution, and incorporating detachable links for easy inspection and maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If coupling systems are integrated within the transmission system, then structural compactness is improved, but maintenance complexity increases due to required disassembly

Engineering Contradiction:
Improvetransmission system volumeVSAvoidcoupling system maintenance
Core Design Contradiction:
Volume of moving objectVSEase of repair

Solution Approach 1:

The coupling system is segmented from the transmission system by positioning it on the output shaft external to the transmission housing. This allows the coupling system to be maintained independently through the free end of the output shaft without disassembling the transmission system, resolving the contradiction between compact integration and maintenance accessibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The free end of the output shaft acts as an intermediary access point, allowing maintenance personnel to reach and service the coupling system without penetrating or disassembling the transmission housing. This intermediary access path enables external maintenance while maintaining structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If coupling systems are positioned outside the transmission system, then maintenance accessibility is improved, but structural integration deteriorates

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidsystem integration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The coupling system is nested within the output shaft structure, which itself is integrated with the transmission system. This nested arrangement allows the coupling system to be externally accessible while still being structurally connected to and protected by the transmission system, balancing accessibility with integration.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Manufacturing precision

If transmission system is disassembled for coupling system maintenance, then complete system inspection is improved, but downtime increases

Engineering Contradiction:
Improvesystem inspection thoroughnessVSAvoidmaintenance downtime
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The coupling system maintenance function is extracted from the transmission system disassembly process. By positioning the coupling system externally on the output shaft, maintenance can be performed by accessing only the coupling system through the free end of the output shaft, leaving the transmission system intact and operational, thus eliminating unnecessary downtime.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If coupling systems require frequent maintenance, then reliability is improved through regular servicing, but operational continuity deteriorates

Engineering Contradiction:
Improvesystem reliabilityVSAvoidoperational continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The coupling system is designed to be self-serviceable through external access via the free end of the output shaft. This allows rapid maintenance without requiring transmission system disassembly, enabling frequent servicing with minimal operational disruption, thus maintaining both high reliability and operational continuity.

Inventive Principle:
Principle #25Self-service

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

Maintenance operations are simplified, reducing downtime and prolonging the time between system maintenance, while maintaining operational efficiency and reducing component degradation.

Implementation Method 1

each coupling system (36) includes a free wheel configured to occupy a coupled state in which the output shaft (34) of the corresponding electric motor (20) is coupled in rotation and transmits a rotational motion to the kinematic chain (26) of the transmission system (22), and an uncoupled state, in case of an incident for example, in which the output shaft (34) of the corresponding electric motor (20) is no longer coupled to the kinematic chain (26) of the transmission system (22) and no longer transmits a rotational motion to it

Methodology Applied
Scientific EffectFree wheel mechanism: Ratchet

Data Source

PatentEP4339104B1Propulsion assembly comprising a transmission system, a plurality of electric motors and at least one offset coupling system, aircraft comprising at least one such propulsion assembly
Publication Date: 2025.11.12 AIRBUS (SAS)
  • EP4339104B1 patent drawingFigure 1~3
  • EP4339104B1 patent drawingFigure 4~5
  • EP4339104B1 patent drawingFigure 6

AI summary

The invention relates to a propulsion assembly comprising a propulsion system, electric motors (44) and a transmission system (46) configured to couple the electric motors (44) to the propulsion system, at least one of the electric motors having an output shaft (60) positioned at a face (56.2) opposite the transmission system (46). In addition, the propulsion assembly includes at least one coupling shaft (64) connecting the output shaft (60) of the electric motor (44) and the transmission system (46), a first coupling system (66), capable of switching to the uncoupled state in the event of an incident at the electric motor (44), configured to rotationally couple the first end (64.1) of the coupling shaft (64) and the output shaft (60) of the electric motor (44) as well as a second coupling system (68) configured to rotationally couple the second end (64.2) of the coupling shaft (64) and the transmission system (46).