Rotating Motor Magnet Teeth Shape for Leakage Flux Reduction

Solution Overview

Problem

Conventional high-speed rotation motors with permanent magnet structures suffer from magnetic leakage flux between stator teeth, leading to reduced efficiency and slower speed response, particularly in high-power applications like internal combustion engine superchargers.

Innovation Solution

A rotating electric motor design featuring stator cores with disk-shaped core backs and teeth that protrude radially, with a magnet shape matching the stator cores, reducing magnetic leakage flux by adjusting the width of the magnet's teeth-shaped portions to minimize flux leakage and enhance flux density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the stator core and magnet are set to have substantially the same shape, then the motor structure is simple and easy to manufacture, but excessive magnetic leakage flux occurs between teeth, causing efficiency deterioration and slower speed response

Engineering Contradiction:

Improvestructural simplicityVSAvoidmagnetic leakage flux

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The magnet is designed with different dimensions than the stator core, specifically making the magnet smaller than the stator core in the radial direction. This local dimensional differentiation ensures that the magnet fits within the stator core's magnetic circuit path, preventing magnetic leakage flux from occurring between adjacent teeth while maintaining overall structural simplicity.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the stator core and magnet are set to have substantially the same shape, then the motor structure is simple, but the speed of response deteriorates due to magnetic leakage flux

Engineering Contradiction:

Improvestructural simplicityVSAvoidspeed of response

Core Design Contradiction:

Ease of manufactureVSSpeed

Solution Approach 1:

The magnet is designed with different dimensions than the stator core, specifically making the magnet smaller than the stator core in the radial direction. This local dimensional differentiation ensures that the magnet fits within the stator core's magnetic circuit path, preventing magnetic leakage flux from occurring between adjacent teeth while maintaining overall structural simplicity.

Inventive Principle:

Principle #3Local quality

3Power

If a large current is supplied to achieve high power, then the motor can provide sufficient torque, but magnetic leakage flux increases, further reducing efficiency and speed response

Engineering Contradiction:

Improvemotor powerVSAvoidmagnetic leakage flux

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The magnet is designed with different dimensions than the stator core, specifically making the magnet smaller than the stator core in the radial direction. This local dimensional differentiation ensures that the magnet fits within the stator core's magnetic circuit path, preventing magnetic leakage flux from occurring between adjacent teeth while maintaining overall structural simplicity.

Inventive Principle:

Principle #3Local quality

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 significantly reduces magnetic leakage flux, improving the motor's efficiency and speed response, making it suitable for ultra-high-speed rotations and enhancing the supercharge capability of internal combustion engine superchargers.

Implementation Method 1

a magnet for field magnetomotive force generation that is sandwiched between the above-mentioned two stator cores and that excites the rotor, and a drive coil for torque generation that is wound around the above-mentioned two stator cores and that causes the rotor to generate a rotary torque

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9225207B2Rotating electric motor and internal combustion engine supercharger

Publication Date: 2015.12.29 MITSUBISHI ELECTRIC MOBILITY CORP

AI summary

Teeth-shaped portions 11b of a magnet 11 are formed in such a way that a part of the plane of projection of each of the teeth-shaped portions protrudes in a circumferential direction with respect to that of one of teeth 8b and 9b which is viewed from an axial direction of a first stator core 8 and a second stator core 9.