Slot Coil Insulating Member With Flange-Guided Resin Flow

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Solution Overview

Problem

Existing insulating members for slot coils in rotary electric machines face challenges in achieving both high insulation and heat resistance while maintaining a thin, precise shape, as resin does not flow smoothly in metallic molds, leading to inefficiencies and potential leaks.

Innovation Solution

The insulating member is designed with flanges on its periphery to serve as flow paths for injected thermoplastic synthetic resin, using thermoplastic synthetic resin with high insulation and heat resistance, and employing high-speed injection molding with specific gate configurations to ensure smooth resin flow into thin partition and outer peripheral walls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the insulating member is made thin to reduce gap between lead wire, then insulation and heat resistance are required, but resin does not flow smoothly in metallic mold making it difficult to form by injection molding

Engineering Contradiction:

Improvethickness of insulating memberVSAvoidmoldability by injection molding

Core Design Contradiction:

Length of moving objectVSEase of manufacture

Solution Approach 1:

The insulating member is divided into regions with different thicknesses: thin partition walls (0.05-0.2mm) for insulation between wires, and thick flanges (0.5-2.0mm) at the ends that serve as resin reservoirs and flow paths during injection molding, enabling both thin overall profile and manufacturability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flanges are designed with greater thickness beforehand to serve as resin reservoirs that guide molten resin flow into the thin partition walls during injection molding, preventing resin short shots and ensuring complete filling of thin sections

Inventive Principle:

Principle #10Preliminary action

2Reliability

If insulation thickness is increased to raise electric insulation, then conversion efficiency of electric motor decreases and electric motor size enlarges

Engineering Contradiction:

Improveelectric insulationVSAvoidconversion efficiency of electric motor

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The insulating member features non-uniform thickness distribution: extremely thin partition walls (0.05-0.2mm) where insulation is needed between adjacent lead wires, while maintaining thick flanges (0.5-2.0mm) at the ends for structural support and resin flow control, achieving insulation with minimal material

Inventive Principle:

Principle #3Local quality

3Volume of moving object

If the insulating member is made thin to reduce motor size, then both insulation and heat resistance are required, but it is difficult to form a thin molded article by injection molding

Engineering Contradiction:

Improvemotor sizeVSAvoidformation precision of thin molded article

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The insulating member is segmented into thin partition walls (0.05-0.2mm) for minimal motor size and thick flanges (0.5-2.0mm) that serve as self-supporting resin reservoirs during molding, enabling precise formation of thin sections by providing molded-in support structures

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The thick flanges act as intermediary structures that facilitate resin flow and provide structural support during injection molding, enabling the formation of thin partition walls that would otherwise be difficult to mold with the required precision

Inventive Principle:

Principle #24Intermediary (Mediator)

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 design allows for the formation of a smooth, precise, and thick flange structure that aligns the insulating member within the slot, preventing resin leaks and ensuring effective electrical insulation and heat resistance, thereby improving the efficiency and reliability of the rotary electric machine.

Implementation Method 1

an insulating member formed by molding of thermoplastic synthetic resin and having through-holes with rectangular cross section for inserting lead wire and parallel to each other as well as having partition walls and outer peripheral walls for insulating the lead wire electrically, wherein the insulating member has a flange formed on periphery at one end thereof and formed to be thicker than the partition walls and the outer peripheral walls, the flange serving as flow path for injected molten resin as thermoplastic synthetic resin when the insulating member is formed by injection molding

Methodology Applied

Scientific EffectInjection molding:

Data Source

PatentUS12407207B2Insulating member for slot coil of rotary electric machine and method for molding the same

Publication Date: 2025.09.02 NAKAGAWA SPECIAL STEEL CO

AI summary

Thermoplastic synthetic resin flowing through both gates 173, 173 into lug part flanges 16, 16 collides with a confronting wall 161, converts direction of flow by 90°, changing velocity of flow, and thus fills the lug part flanges 16, 16 and flanges 15,15 on the long side. After this, as thermoplastic synthetic resin flows into thin outer peripheral walls 131, 132 and partition walls 133 at an optimum velocity of flow, thermoplastic synthetic resin flows smoothly and it is possible to form a smooth molded article. The lug part flanges 16,16 and the flanges 15, 15 on the long side serve as runners, so that thermoplastic synthetic resin flows smoothly into the thin outer peripheral walls 131,132 and partition wall 133.