Halbach Stator Core Projections to Prevent Magnet Detachment

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Solution Overview

Problem

The detachment of magnets from the stator core due to different magnetization directions in a Halbach array configuration is a concern, particularly for radially outward magnets, which are biased radially inward by magnetic forces from adjacent magnets.

Innovation Solution

A stator design with a Halbach array of magnets, where each magnet has inclined surfaces supported by projections on the stator core, which are inclined inwardly to counteract the magnetic forces, preventing detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a Halbach array configuration is used to concentrate magnetic flux radially inward, then magnetic performance is improved, but magnets may detach from the stator core due to radial inward magnetic forces

Engineering Contradiction:
Improvemagnetic flux concentrationVSAvoidmagnet detachment risk
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by providing support projections on the stator core that extend into the magnets before detachment can occur. These projections are positioned to counteract the radial inward magnetic forces generated by the Halbach array configuration, preventing magnet detachment while maintaining the magnetic performance benefits.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent segments the support structure into multiple discrete support projections distributed around the stator core. Each projection independently supports adjacent magnets, allowing the system to maintain overall magnetic flux concentration while providing localized counter-forces to prevent detachment at specific positions.

Inventive Principle:
Principle #1Segmentation

2Reliability

If support structures are added to prevent magnet detachment, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvemagnet detachment suppressionVSAvoidstator structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the support projections with the stator core structure, making them an integrated part of the core rather than separate components. This combining approach provides necessary mechanical support to prevent magnet detachment while avoiding the complexity of additional independent support structures or assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stator core structure serves dual functions: it provides the magnetic path and simultaneously incorporates support projections that prevent magnet detachment. The core structure essentially supports itself by including the necessary anti-detachment features as integral parts, eliminating the need for separate support mechanisms.

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

The design effectively suppresses magnet detachment with a simple configuration, enhancing stability and reducing the risk of magnets coming off the stator core.

Implementation Method 1

a radially outward magnetized magnet is biased radially inward by a magnetic force from the other magnets

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP4708650A1Stator, magnetic gear electric machine, and method for assembling stator
Publication Date: 2026.03.11 MITSUBISHI HEAVY IND LTD
  • EP4708650A1 patent drawingFigure 1
  • EP4708650A1 patent drawingFigure 2
  • EP4708650A1 patent drawingFigure 3

AI summary

A stator core includes: a core inner peripheral surface along which a plurality of magnets is arranged; a first projection protruding radially inward from the core inner peripheral surface and having a first support surface supporting the first inclined surface; and a second projection protruding radially inward from the core inner peripheral surface and having a second support surface supporting the second inclined surface. Both the first support surface and the second support surface are inclined with respect to the radial direction and slope toward the center of the first radial magnet as they extend radially inward.