Recessed Core Piece Structure for Coil Insulation Protection

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Solution Overview

Problem

The insulating coating of coils in reactors with molded resin portions is prone to damage during manufacturing due to contact with detached soft magnetic particles from the gate mark during the resin solidification process.

Innovation Solution

The core piece is designed with a recessed portion and a gate mark located inside the recessed portion to contain detached soft magnetic particles, preventing them from entering the coil and causing friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a molded resin portion is used to cover the magnetic core and coil, then productivity and ease of manufacture are improved, but the insulating coating of the coil may become damaged due to contact with detached soft magnetic particles from the gate mark

Engineering Contradiction:

ImproveproductivityVSAvoidinsulating coating integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention converts the harmful effect of detached soft magnetic particles from the gate mark into a beneficial containment system. By designing a recessed portion that specifically captures these particles, the harmful detachment phenomenon is redirected to serve the protective function of preventing particle migration to the coil, thus converting a manufacturing defect source into a protective feature

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The recessed portion acts as an intermediary structure between the gate mark and the coil. It serves as a containment zone that intercepts detached soft magnetic particles before they can reach the coil, thereby protecting the insulating coating while allowing the gate mark to remain functional for resin injection

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the gate mark is positioned at the bottom portion of the recessed portion, then detached soft magnetic particles are contained within the recessed portion, but the structural complexity of the core piece increases

Engineering Contradiction:

Improveparticle containmentVSAvoidcore piece structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The recessed portion is created only at the specific location where the gate mark exists, rather than modifying the entire core piece structure. This localized structural change provides particle containment functionality only where needed, minimizing overall structural complexity while achieving the required protective effect

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The core piece structure is segmented into distinct functional zones: the recessed portion for particle containment, the gate mark for resin injection, and the remaining core structure for magnetic function. This segmentation allows each zone to perform its specific function independently, simplifying the overall design compared to a completely redesigned core structure

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12573531B2Core piece, reactor, converter, and power conversion apparatus

Publication Date: 2026.03.10 AUTONETWORKS TECH LTD

AI summary

A core piece of the present invention is constituted by a molded body of a composite material in which a soft magnetic powder is dispersed in a resin. The core piece includes an end core portion configured to face an end face of a coil. The end core portion includes a recessed portion provided outside the coil, and a gate mark provided at a bottom portion of the recessed portion. An end face of the gate mark is located inside the recessed portion.