Clocked Electric Machine Layout for Hybrid Aircraft Gearbox Integration

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Solution Overview

Problem

Existing hybrid-electric propulsion systems for aircraft lack optimal integration and efficiency in combining gas turbine engines with electric machines, particularly in terms of spatial arrangement and power distribution.

Innovation Solution

A propulsion system design that includes a geartrain, propulsor rotor, turbine engine core, electric machine, and accessory gearbox, where the electric machine and accessory gearbox are circumferentially offset from the turbine engine core, allowing for improved spatial arrangement and power distribution through the use of a geartrain and tower shaft connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the electric machine and accessory gearbox are integrated in a conventional co-located arrangement, then the structure is simpler, but the spatial arrangement efficiency and power distribution optimization are limited

Engineering Contradiction:
Improvestructural simplicityVSAvoidpower distribution efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent transitions from a conventional planar co-located arrangement to a three-dimensional spatial distribution where the electric machine and accessory gearbox are separated along the circumferential direction but connected through axial overlap. This dimensional reconfiguration enables optimized power distribution pathways while maintaining structural integrity through the geartrain and tower shaft connections.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If the electric machine and accessory gearbox are circumferentially offset and axially overlapped, then the spatial arrangement and power distribution are optimized, but the structural complexity increases

Engineering Contradiction:
Improvepower distribution efficiencyVSAvoidspatial arrangement complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the propulsion system into distinct functional modules: the electric machine, the accessory gearbox, and the geartrain, positioning them in separate spatial zones. The electric machine is circumferentially offset from the turbine engine core, while the accessory gearbox is positioned in the axial overlap region. This segmentation allows each component to be optimized independently while maintaining efficient power flow through the geartrain connections.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If conventional hybrid-electric propulsion systems are used, then the implementation is straightforward, but the integration efficiency and system performance are suboptimal

Engineering Contradiction:
Improveimplementation easeVSAvoidsystem integration efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The geartrain serves as an intermediary mechanism that facilitates efficient power distribution between the turbine engine core, the circumferentially offset electric machine, and the axially overlapped accessory gearbox. This intermediary connection enables optimized power flow pathways, improving overall system integration efficiency while maintaining implementation feasibility through established geartrain technology.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4671130A1Aircraft propulsion system with clocked electric machine and accessory gearbox
Publication Date: 2025.12.31 PRATT & WHITNEY CANADA CORP
  • EP4671130A1 patent drawingFigure 1
  • EP4671130A1 patent drawingFigure 2
  • EP4671130A1 patent drawingFigure 3A~3B

AI summary

A propulsion system (20) is provided for an aircraft. This propulsion system (20) includes a geartrain (62), a propulsor rotor (22), a turbine engine core (24), an electric machine (28) and an accessory gearbox system (30). The propulsor rotor (22) is disposed to a first side (88) of the geartrain (62). The turbine engine core (24) is disposed to a second side (90) of the geartrain (62). The turbine engine core (24) is operatively coupled to the propulsor rotor (22) through the geartrain (62). The electric machine (28) is disposed to the second side (90) of the geartrain (62). The electric machine (28) is operatively coupled to the propulsor rotor (22) and/or the turbine engine core (24) through the geartrain (62). The accessory gearbox system (30) is operatively coupled to the turbine engine core (24). The accessory gearbox system (30) is circumferentially offset from the electric machine (28) about a centerline axis of the turbine engine core (24). The accessory gearbox system (30) axially overlaps the electric machine (28) along the centerline axis of the turbine engine core (24).