Rotor Magnet Resin Curing to Prevent Core Lamination Leakage

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Solution Overview

Problem

The resin injected into the rotor core leaks between stacked steel sheets due to the long molten resin curing period, even when the rotor core is urged in a jig during heating.

Innovation Solution

The resin is cured at a curing start temperature or higher by heating the rotor core to prevent leakage between stacked steel sheets, using a holding jig and induction heaters to maintain the required temperature during resin injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a rotor is divided into multiple sections for manufacturing, then ease of manufacture is improved, but the number of assembly steps increases and assembly precision becomes more difficult to ensure

Engineering Contradiction:
Improveease of manufactureVSAvoidassembly precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-forming recesses in the rotor sections at the time of section manufacturing, rather than attempting to form them during assembly. This preliminary preparation of the recesses allows for precise positioning and fitting of the rotor core and coil units, ensuring assembly precision while maintaining the benefits of divided-section manufacturing.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If rotor sections are manufactured separately and then assembled, then ease of manufacture is improved, but the number of parts increases and assembly complexity increases

Engineering Contradiction:
Improveease of manufactureVSAvoidassembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges multiple components into integrated assemblies. Specifically, the rotor core and coil units are combined into pre-assembled rotor core-coil unit assemblies, which are then installed as single units into the rotor sections. This merging reduces the number of discrete assembly steps and simplifies the overall assembly process while still allowing the rotor to be manufactured in separate sections.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If the rotor is manufactured as a single integrated unit, then assembly precision is maintained, but ease of manufacture decreases and manufacturing complexity increases

Engineering Contradiction:
Improveassembly precisionVSAvoidease of manufacture
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent divides the rotor into multiple manufacturable sections that can be produced separately using standard manufacturing processes. Each section is designed with specific recesses that accommodate rotor core-coil unit assemblies. This segmentation enables easier manufacturing of each individual section while the overall rotor assembly maintains precision through the carefully designed interface features between sections.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4216411B1Method for manufacturing rotor
Publication Date: 2026.04.22 AISIN CORP
  • EP4216411B1 patent drawingFigure 1
  • EP4216411B1 patent drawingFigure 2
  • EP4216411B1 patent drawingFigure 3

AI summary

A rotor manufacturing method for manufacturing a rotor of a rotary electric machine by disposing magnets in hole portions of a rotor core formed of stacked steel sheets, and injecting and curing a thermosetting resin to fix the magnets to the rotor core includes a temperature increasing step for increasing a temperature of the rotor core to a curing start temperature (T3) or higher, a resin injection step for causing a resin injection apparatus to inject the liquid resin at a melting start temperature (T1) or higher into the hole portions of the rotor core at the curing start temperature (T3) or higher, and a magnet fixing step for curing the resin by keeping the rotor core at the curing start temperature (T3) or higher.