Permanent Magnet Rotary Machine With Narrow Stator Teeth for Torque

Solution Overview

Problem

Existing rotary electric machines with distributed winding stator coils face reduced workability when increasing capacity, while concentrated winding stator coils result in reduced torque and increased machine size, posing challenges in achieving high induced voltage and torque simultaneously.

Innovation Solution

A permanent magnet-type rotary electric machine with stator coils configured in a concentrated winding manner and stator magnets magnetized in the same direction, featuring narrower stator teeth between adjacent slots to enhance torque and reduce leakage magnetic flux.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If stator coils are wound in a concentrated winding manner to suppress reduction in workability, then workability is improved, but generated torque is reduced

Engineering Contradiction:

Improveworkability of stator coilsVSAvoidgenerated torque

Core Design Contradiction:

Ease of manufactureVSForce

Solution Approach 1:

The invention applies different circumferential widths to different stator teeth: stator teeth positioned between stator magnets have a narrower circumferential width, while other stator teeth have a wider circumferential width. This local differentiation optimizes the magnetic flux distribution to improve torque generation while maintaining concentrated winding workability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the geometric parameter of stator teeth by setting the circumferential width of teeth between stator magnets to be narrower than the width of stator slots. This parameter modification optimizes the magnetic circuit to enhance torque output in concentrated winding configurations

Inventive Principle:

Principle #35Parameter changes

2Power

If machine size is increased to increase capacity, then generated power is improved, but workability of stator coils is reduced

Engineering Contradiction:

Improvegenerated powerVSAvoidworkability of stator coils

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The invention applies different circumferential widths to different stator teeth: stator teeth positioned between stator magnets have a narrower circumferential width, while other stator teeth have a wider circumferential width. This local differentiation optimizes the magnetic flux distribution to improve torque generation while maintaining concentrated winding workability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the geometric parameter of stator teeth by setting the circumferential width of teeth between stator magnets to be narrower than the width of stator slots. This parameter modification optimizes the magnetic circuit to enhance torque output in concentrated winding configurations

Inventive Principle:

Principle #35Parameter changes

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

The solution improves generated torque and reduces machine size by optimizing stator coil configuration and magnetic flux distribution, allowing for increased induced voltage and efficient power generation.

Implementation Method 1

Linkage of magnetic force generated from the permanent magnets of the second rotor increased in speed with the stator coils induces a generated power in the stator coils

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the torque is generated in the first rotor by modulation of the magnetic force from the stator magnets and the magnetic force from the permanent magnets of the second rotor by the pole pieces of the first rotor

Methodology Applied

Scientific EffectMagnetic force interaction: Magnetism

Data Source

PatentUS12620846B2Permanent magnet-type rotary electric machine

Publication Date: 2026.05.05 MITSUBISHI ELECTRIC CORP

AI summary

A permanent magnet-type rotary electric machine comprises: a stator including: a stator core having a plurality of stator teeth formed circumferentially; stator coils arranged in the respective bottoms of a plurality of stator slots formed between the stator teeth and wound on the stator teeth in a concentrated winding manner; and stator magnets arranged near the respective openings of the plurality of stator slots, a first rotor having a plurality of pole pieces and disposed coaxially with the stator to face the stator magnets; and a second rotor having a plurality of permanent magnets and disposed coaxially with the first rotor to face the first rotor, wherein the circumferential width of stator teeth positioned between the adjacent two of the stator magnets is narrower than the circumferential width of the stator slots.