Integrated Rotor Fan Assembly for Aircraft Motor Cooling

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Solution Overview

Problem

Traditional electric motors for aircraft applications face challenges in minimizing weight while maintaining high power density and efficiency, particularly due to the weight burden of dense permanent magnets, and require advanced cooling solutions to manage thermal limitations effectively.

Innovation Solution

The design incorporates a rotor assembly with an outer and inner diameter portion, an end portion, and a fan assembly that induces cooling flow through the stator cavity, along with a compact thermal management system using lightweight materials and non-magnetic structures with embedded magnetic wires to reduce torque ripple and weight, while integrating fan assemblies for enhanced airflow and heat extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If dense permanent magnets are used to maximize magnetic loading, then torque density is improved, but weight increases

Engineering Contradiction:
Improvetorque densityVSAvoidrotor weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent combines the cooling fan function with the rotor structure by integrating fan blades into the rotor body, eliminating the need for separate cooling components and reducing overall weight while maintaining high magnetic loading for torque density

Inventive Principle:
Principle #5Merging (Combining)

2Temperature

If advanced cooling solutions are implemented, then thermal management is improved, but device complexity increases

Engineering Contradiction:
Improvethermal managementVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The rotor serves its own cooling needs by incorporating fan blades directly into its structure, allowing the rotating component to generate its own cooling airflow without requiring external cooling systems or additional complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The cooling function is merged with the rotor structure itself, combining two functions (rotation and cooling) into a single integrated component, thereby reducing overall system complexity

Inventive Principle:
Principle #5Merging (Combining)

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

This configuration achieves reduced weight, improved thermal and power efficiency, and increased power density by effectively managing thermal loads and minimizing torque ripple, enabling efficient operation under varying aircraft power conditions.

Implementation Method 1

at least one fan assembly arranged in the rotor assembly and configured to induce a cooling flow through the stator cavity

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Data Source

PatentEP4412044A1Electric machine having rotor with integrated fan
Publication Date: 2024.08.07 RTX CORP
  • EP4412044A1 patent drawingFigure 1A~1B
  • EP4412044A1 patent drawingFigure 2A
  • EP4412044A1 patent drawingFigure 2B

AI summary

An aircraft electric motor includes a rotor assembly (500) having an outer diameter portion (502), an inner diameter portion (504), and an end portion (506), arranged to define a stator cavity (534), and a rotor hub (510) configured to connect to a shaft of the aircraft electric motor, a stator assembly arranged within the stator cavity (534), and at least one fan assembly (530,532) arranged in the rotor assembly (500) and configured to induce a cooling flow through the stator cavity (534).