Motor Core Production via Magnetic Phase Diffusion

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Solution Overview

Problem

The existing methods for producing motor cores with embedded permanent magnets have a limited degree of freedom in design due to the need for multiple molds and difficulty in inserting magnets with complex shapes into soft magnetic plate laminates.

Innovation Solution

A method involving the diffusion and penetration of rare earth elements into soft magnetic plates to form hard magnetic phases at specific positions, allowing for the creation of motor cores with varying shapes and designs without the need for multiple molds, using modifying members with lower melting points than the soft magnetic plates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If molded articles (permanent magnets) are used, then production is simplified, but the degree of freedom in shape is limited and multiple molds are required

Engineering Contradiction:
Improveproduction simplicityVSAvoiddegree of freedom in shape
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the physical state and composition parameters of the soft magnetic plate by introducing modifying members containing rare earth elements. Through heat treatment, the modifying members diffuse into the soft magnetic plate to form hard magnetic phases, transforming the material properties directly within the plate rather than using separate molded magnets. This enables complex shapes without requiring multiple molds.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent merges the functions of the soft magnetic plate and the permanent magnet into a single integrated structure. The modifying members are brought into contact with the soft magnetic plate, and through diffusion and heat treatment, the hard magnetic phase is formed within the soft magnetic plate itself, combining what were previously separate components into one unified motor core structure.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If multiple types of permanent magnets are prepared, then various motor core types are supported, but the number of molds required increases

Engineering Contradiction:
Improvevariety of motor core typesVSAvoidnumber of molds
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal producing method that can generate various types of motor cores using a single basic process. By controlling the position, amount, and composition of the modifying members, and adjusting heat treatment parameters, the same diffusion-based method can produce different hard magnetic phase patterns suitable for various motor core types, eliminating the need for multiple specialized molds.

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

Solution Approach 2:

The patent applies local quality by allowing different regions of the soft magnetic plate to have different magnetic properties through selective placement of modifying members. The modifying members can be positioned at specific locations and in specific amounts to create localized hard magnetic phases with different characteristics, enabling diverse motor core designs within a single unified production approach.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If through-holes are punched to form cavity parts, then permanent magnets can be embedded, but punching molds are required and the process becomes complex

Engineering Contradiction:
Improveembedding capabilityVSAvoidpunching mold requirements
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical punching process with a thermal diffusion process. Instead of using punching molds to create physical cavities, the modifying members are brought into contact with the soft magnetic plate and heat-treated to diffuse rare earth elements into the plate, forming hard magnetic phases in the desired locations. This substitutes mechanical cavity formation with a thermal-chemical process that directly creates the magnetic structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If complex shaped permanent magnets are used, then design freedom is increased, but insertion into the laminate becomes difficult

Engineering Contradiction:
Improvedesign freedomVSAvoidinsertion ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent performs preliminary action by forming the hard magnetic phases directly within the soft magnetic plate during the heat treatment process, before any assembly operations. The modifying members are placed on the soft magnetic plate surface, and through diffusion and heat treatment, the complex magnetic structures are created in situ within the plate itself, eliminating the need for subsequent insertion operations.

Inventive Principle:
Principle #10Preliminary action

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 approach enables the production of motor cores with a high degree of design freedom, allowing for complex shapes and reduced production costs by eliminating the need for multiple molds and simplifying the insertion of magnets, while maintaining effective magnetic properties.

Implementation Method 1

causing each modifying member to diffuse and penetrate into the soft magnetic plate from a contact surface between the soft magnetic plate and the modifying member

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

preparing modifying members containing an alloy having a melting point lower than a melting point of the soft magnetic plate

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3713046B1Method of producing motor core
Publication Date: 2023.05.17 TOYOTA JIDOSHA KK
  • EP3713046B1 patent drawingFigure 1A~2B
  • EP3713046B1 patent drawingFigure 2C~3A
  • EP3713046B1 patent drawingFigure 3B~3D

AI summary

A method of producing a motor core (30) includes preparing soft magnetic plates (11) containing a transition metal element, preparing a modifying member (21) containing an alloy having a melting point lower than a melting point of the soft magnetic plate (11), bringing the modifying member (21) into contact with part of a plate surface of the soft magnetic plate (11), causing the modifying member to diffuse and penetrate into the soft magnetic plate (11) from a contact surface between the soft magnetic plate (11) and the modifying member (21) and forming a hard magnetic phase-containing part (16) in part of the soft magnetic plate (11), and laminating a plurality of soft magnetic plates (11) on each other after the modifying member (21) is brought into contact with part of the plate surface of the soft magnetic plates (11).