Dual-Layer Coreless Stator Structure for Higher Interlinking Flux

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Solution Overview

Problem

Existing rotating electric machines with coreless coils struggle to maximize the interlinking magnetic flux, which affects torque generation in motors and voltage induction in generators.

Innovation Solution

A stator structure comprising an inner and outer coil layer with coreless coils arranged in a circumferential direction, where each coil pitch is equal to or greater than 360° divided by the total number of coils, increasing the area occupied by the coils and enhancing interlinking magnetic flux.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If coreless coils are used in the stator, then weight is reduced, but the amount of interlinking magnetic flux is insufficient

Engineering Contradiction:
Improveweight of statorVSAvoidamount of interlinking magnetic flux
Core Design Contradiction:
Weight of moving objectVSQuantity of substance

Solution Approach 1:

The patent introduces a dual-layer coil structure (inner coil layer and outer coil layer) arranged in the radial direction, transforming the single-layer planar arrangement into a three-dimensional spatial configuration. This dimensional change allows coils to be arranged more densely while maintaining adequate spacing, thereby increasing the total amount of interlinking magnetic flux without compromising the weight reduction benefit of coreless construction

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

2Quantity of substance

If coil pitch is increased to maximize interlinking magnetic flux, then magnetic flux amount increases, but coil insulation becomes more difficult to maintain

Engineering Contradiction:
Improveamount of interlinking magnetic fluxVSAvoidcoil insulation reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent divides the coil structure into two separate layers (inner and outer coil layers) with distinct insulation arrangements. Each layer has its own insulation structure, and the layers are separated by a specific radial distance. This segmentation allows independent optimization of insulation for each layer while achieving increased coil pitch and magnetic flux linkage in the overall structure

Inventive Principle:
Principle #1Segmentation

3Quantity of substance

If multiple coil layers are arranged closely to increase magnetic flux, then interlinking magnetic flux increases, but risk of coil contact increases

Engineering Contradiction:
Improveamount of interlinking magnetic fluxVSAvoidcoil contact risk
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an insulation structure that acts as an intermediary between the inner and outer coil layers. This insulation structure includes insulation films and insulation ribs that physically separate the two layers, preventing direct contact while allowing close spatial arrangement. The intermediary insulation structure enables the dual-layer configuration to achieve increased magnetic flux linkage without the harmful effect of coil contact

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 configuration increases the amount of interlinking magnetic flux, thereby improving torque in motors and voltage induction in generators, while ensuring effective electrical insulation and preventing coil contact.

Implementation Method 1

a rotating magnetic field is generated by applying a voltage to a coil of the stator. Then, the rotor is rotated by the generated rotating magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an electromotive force is induced on the rotor by the rotating magnetic field, and the rotor is rotated by the induced electromotive force

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a voltage (electromotive force) is induced on a coil of the stator by a rotating magnetic field generated by rotation of the rotor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4648263A1Stator structure of rotating electric machine
Publication Date: 2025.11.12 KK TOSHIBA
  • EP4648263A1 patent drawingFigure 1
  • EP4648263A1 patent drawingFigure 2
  • EP4648263A1 patent drawingFigure 3

AI summary

In an embodiment, a stator structure in a rotating electric machine includes an inner coil layer and an outer coil layer. In the inner coil layer, a plurality of coreless inner coils are arranged side by side in a circumferential direction. In the outer coil layer, a plurality of coreless outer coils are arranged side by side in the circumferential direction on an outer peripheral side of the inner coil layer in a state not contacting the inner coils. Each coil pitch of the inner coils and the outer coils is equal to or greater than an angle obtained by dividing 360° by a total number of the inner coils and the outer coils.