Brushless Ring Motor Layout for High-Temperature Torque Stability

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Solution Overview

Problem

Rotary electric machines face challenges in operating in extreme temperature environments, such as those found in turbine jet engines, due to the loss of magnetism in permanent magnet machines, and there is a need for a design that can withstand high temperatures while maintaining efficient torque generation.

Innovation Solution

A brushless electric ring motor with an inner rotor and outer stator configuration, utilizing ferritic elements made of electrical steel and radially-oriented ferromagnetic elements, coupled with a guide element, to generate magnetic force and torque efficiently in high-temperature conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If permanent magnet electric machines are used, then efficient torque generation is achieved, but loss of magnetism occurs in high temperature environments

Engineering Contradiction:
Improvetorque generation efficiencyVSAvoidmagnetism retention at high temperature
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent changes the material parameter from permanent magnet to ferromagnetic material that does not lose its magnetic properties at high temperatures. The stator uses ferromagnetic material with specific magnetic properties that remain stable in extreme temperature environments, eliminating the magnetism loss problem while maintaining torque generation capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structure combining ferromagnetic material in the stator with specific magnetic properties. The stator comprises ferromagnetic material that can be magnetized and maintains its magnetic characteristics at high temperatures, creating a composite solution that addresses both power generation and thermal stability requirements.

Inventive Principle:
Principle #40Composite materials

2Power

If conventional rotary electric machine designs are used, then basic torque generation is achieved, but torque ripple and vibration increase in high temperature conditions

Engineering Contradiction:
Improvetorque generationVSAvoidtorque ripple and vibration
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent segments the stator into multiple independent windings arranged circumferentially around the rotor. Each winding can be controlled independently, allowing for optimized current distribution that reduces torque ripple and vibration while maintaining effective torque generation in high temperature environments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different magnetic properties to different regions of the stator by using ferromagnetic material with specific local characteristics. The stator structure incorporates regions with optimized magnetic permeability and coercivity to minimize harmful torque fluctuations and vibrations while maintaining overall torque generation efficiency.

Inventive Principle:
Principle #3Local quality

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 design enables continuous operation at sustained high temperatures without loss of power, reducing torque ripple and vibration, and providing efficient torque generation.

Implementation Method 1

electric power is converted to mechanical power in the form of torque using sequentially applied electromagnetic power

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the plurality of radially-oriented, inwardly-projecting ferromagnetic elements are arranged to exert magnetic force on the plurality of ferritic elements when the plurality of electro-magnetic elements are electrically activated

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Implementation Method 3

the plurality of radially-oriented, inwardly-projecting ferromagnetic elements are magnetically coupled to corresponding ones of the electro-magnetic elements

Methodology Applied
Scientific EffectMagnetic coupling: Magnetic Field

Implementation Method 4

torque is generated through magnetic reluctance

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Data Source

PatentEP4037167B1Rotary electric machine
Publication Date: 2025.10.29 THE BOEING CO
  • EP4037167B1 patent drawingFigure 1
  • EP4037167B1 patent drawingFigure 2
  • EP4037167B1 patent drawingFigure 3~4

AI summary

A rotary electric machine (100, 660) arranged as a brushless electric ring motor is described and includes a rotor (50, 650) that is disposed within a stator (20, 620) and arranged to rotate on a guide element (13, 613). The rotor (50, 650) has a plurality of ferritic elements (60, 664) arranged on an outer surface (54, 663), and the stator (20, 620) is an annular device having a plurality of electro-magnetic elements (25, 668) arranged on an inner portion (32) between first (21, 667) and second flanges (22, 669). The first and second flanges both include an annular ring (652) that is fabricated from a non-magnetic material and has a plurality of ferromagnetic elements (28). The ferromagnetic elements (28) are magnetically coupled to corresponding ones of the electro-magnetic elements (25, 668) to exert magnetic force on the ferritic elements (60, 664) of the rotor when the electro-magnetic elements (25, 668) are activated. The rotary electric machine may operate as a first thrust generating system that is upstream of a second thrust generating system for a turbojet engine.