Annular Resin Filling for Motor Core Magnet Fixing

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Solution Overview

Problem

The existing method of mounting permanent magnets in motor cores results in a long resin fill path, leading to excessive resin usage and hardening outside the fill portions, which increases material costs and inefficiencies.

Innovation Solution

A motor core manufacturing device with a mold structure that includes convex portions within the chamber and short resin fill paths, along with a plunger mechanism, to minimize resin hardening outside the fill portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the resin tablet is placed in the central portion of the gate mold, then the magnets can be fixed in the motor core, but the resin fill path becomes long and excessive resin hardens outside the fill portions

Engineering Contradiction:
Improvemagnet fixingVSAvoidresin waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The invention changes the spatial arrangement from a conventional central pot to an annular chamber positioned at the outer periphery of the motor core. This dimensional repositioning aligns the resin source closer to the magnet insertion holes, reducing the fill path length and minimizing resin waste that hardens outside the intended fill portions.

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

Solution Approach 2:

The annular chamber is positioned specifically at the outer periphery where the magnet insertion holes are located, creating a localized resin supply system. This local positioning ensures resin is delivered directly to the required areas without excessive travel distance, reducing overall resin consumption while maintaining effective magnet fixing.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If the resin fill path is long, then the magnets can be reached, but the amount of resin that hardens outside the resin fill portions increases

Engineering Contradiction:
Improveresin fillingVSAvoidresin consumption
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The annular chamber configuration and peripheral positioning create a shorter, more direct resin fill path from the resin source to the magnet insertion holes. This spatial optimization reduces the distance resin must travel, thereby reducing the quantity of resin that hardens outside the intended fill portions.

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

3Loss of substance

If the convex portions are added to the chamber, then the resin usage is reduced, but the device complexity increases

Engineering Contradiction:
Improveresin waste reductionVSAvoidchamber structure
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

Convex portions are added to specific localized areas of the annular chamber to control resin flow and prevent excessive resin from hardening outside the fill portions. These localized structural modifications target specific problem areas without requiring a complete redesign of the entire chamber, thus achieving resin waste reduction with minimal increase in overall device complexity.

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

Reduces the amount of resin used and hardening within the chamber, improving manufacturing efficiency and reducing material waste.

Implementation Method 1

an annular plunger that can move within the annular chamber

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP4693844A1Motor core manufacturing device and motor core manufacturing method
Publication Date: 2026.02.11 NHK SPRING CO LTD
  • EP4693844A1 patent drawingFigure 1
  • EP4693844A1 patent drawingFigure 2A~2B
  • EP4693844A1 patent drawingFigure 3A~3B

AI summary

A motor core manufacturing device of the present disclosure includes: a mold that can hold a motor core including plural resin fill portions disposed in an annular form at a predetermined interval, and the mold includes a first mold and a second mold; an annular chamber communicating with resin fill paths, which are formed in the first mold and whose end portions can communicate with the plural resin fill portions respectively, and an annular resin material of a predetermined wall thickness can be accommodated in an interior of the annular chamber; an annular plunger that can move within the annular chamber; and one or plural convex portions projecting toward an inner side of the annular chamber from an inner surface within the annular chamber except at portions that communicate with the resin fill paths.