Segmented Input Shaft With Overrunning Clutches for Multi-Motor Gearboxes

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Solution Overview

Problem

Aircraft propulsion systems with a single electric motor are prone to failure and inefficient in meeting power demands, while multi-motor systems face manufacturing challenges and increased complexity.

Innovation Solution

A segmented input shaft and overrunning clutch design for an electric motor stack and gearbox unit, where each motor drives a gearbox input shaft segment with splined connectors, allowing for assembly and quality control improvements and reducing manufacturing costs and precision requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single electric motor is used in the propulsion system, then the system complexity is reduced, but the reliability decreases and power demand efficiency is insufficient

Engineering Contradiction:
Improvesystem complexityVSAvoidreliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The propulsion system is segmented into multiple independent motor modules (typically three), each capable of independent operation. This segmentation allows the system to maintain lower individual component complexity while achieving higher overall reliability through redundancy - if one motor fails, the others can continue to operate and drive the propeller.

Inventive Principle:
Principle #1Segmentation

2Reliability

If two or more electric motors are used in the propulsion system, then reliability and power demand efficiency are improved, but device complexity and manufacturing challenges increase

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system is divided into modular motor units with standardized interfaces. Each motor module is a self-contained unit with its own mounting structure and connection points, allowing for simplified assembly and reducing overall system complexity despite having multiple motors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple motor modules are merged together with their output shafts coupled to a common propeller shaft. The motors are positioned radially around the shaft and connected through standardized coupling mechanisms, consolidating multiple power sources into a unified propulsion system that maintains manageable complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multiple electric motors are used in the propulsion system, then reliability and power efficiency are improved, but manufacturing cost and precision requirements increase

Engineering Contradiction:
ImprovereliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The propulsion system is segmented into identical or similar motor modules that can be manufactured using the same processes and tooling. This modular segmentation allows for economies of scale in manufacturing, reducing the cost per unit while maintaining the reliability benefits of having multiple motors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The motor modules are designed with universal, standardized interfaces and mounting configurations that can be used across different modules. This universality simplifies manufacturing by reducing the number of unique parts and assembly variations, thereby lowering overall manufacturing costs while maintaining the multi-motor reliability configuration.

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

Data Source

PatentEP3930158B1Segmented input shaft for electric motor stack and gearbox unit
Publication Date: 2024.02.14 TEXTRON INNOVATIONS INC
  • EP3930158B1 patent drawingFigure 1A
  • EP3930158B1 patent drawingFigure 1B
  • EP3930158B1 patent drawingFigure 2

AI summary

A motor assembly is described and includes a housing; a plurality of motors (406A-C) disposed within the housing; and a drive shaft comprising a plurality of interconnected drive shaft segments (410A-C), wherein each one of the drive shaft segments (410A-C) is driven by a different one of the motors (406A-C) connected to the drive shaft segment (410A-C) via an integrated overrunning clutch (412A-C).