Electric Motor Rotor Halbach Array Magnet Arrangement

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Solution Overview

Problem

The existing rotor designs for electric motors face limitations in downsizing while maintaining high output, as they require additional areas for fixing magnets and suffer from magnetic flux intrusion into the rotation shaft, leading to inefficiencies.

Innovation Solution

A rotor design featuring a Halbach array configuration with auxiliary magnets fitted into grooves along the rotation shaft and main magnets arranged between them, where the auxiliary magnets have a larger radial extension ratio and a simpler shape, reducing the number of poles and eliminating the need for special fixation areas, thereby allowing for downsizing and improved magnetic flux management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rare earth metallic powders are used to sinter gaps between magnets to fix them in predetermined positions, then the magnets can be securely fixed, but the rotor size cannot be reduced while maintaining high output

Engineering Contradiction:

Improvemagnet fixation stabilityVSAvoid rotor size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The invention extracts and eliminates the sintered rare earth metallic powder fixation area from the rotor structure. Instead of using sintered gaps between magnets, the patent uses a Halbach array configuration where magnets are directly arranged adjacent to each other, removing the need for additional fixation material and space.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the magnetic arrangement parameters by implementing a Halbach array pattern, which alters the magnetic field distribution to prevent flux intrusion into the rotation shaft. This parameter change allows for more efficient space utilization without requiring additional fixation areas.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional magnet arrangement is used, then magnets can be easily positioned, but magnetic flux intrudes into the rotation shaft side reducing motor output

Engineering Contradiction:

Improvemagnet arrangement simplicityVSAvoidmotor output

Core Design Contradiction:

Ease of manufactureVSPower

Solution Approach 1:

The invention applies asymmetry by implementing a Halbach array configuration where the magnetization directions of adjacent magnets are deliberately arranged in a specific asymmetric pattern. This asymmetric arrangement causes magnetic flux to be directed away from the rotation shaft, preventing flux intrusion and improving motor output.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The invention converts the potential harmful effect of magnetic flux leakage into a beneficial pattern by using the Halbach array configuration. The specific arrangement of magnetization directions transforms what would be stray flux into a controlled magnetic field pattern that enhances motor performance.

Inventive Principle:

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

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 enhances the electric motor's output by preventing magnetic flux intrusion into the rotation shaft, allowing for stable performance and high-speed operation while reducing the rotor's size and assembly complexity.

Implementation Method 1

a rotor including a plurality of main magnets and a plurality of auxiliary magnets... the auxiliary magnets... have a magnetization direction along a circumferential direction of the rotor... the main magnets... have a magnetization direction that is along the radial direction of the rotor

Methodology Applied

Scientific EffectMagnetism: Magnetism

Implementation Method 2

the plurality of main magnets and the plurality of auxiliary magnets are arranged in such a way that the main magnets and the auxiliary magnets form a Halbach array in the circumferential direction of the rotor... it is possible to prevent the magnetic flux from the main magnets from intruding into the side of the rotation shaft

Methodology Applied

Scientific EffectHalbach array: Halbach Array

Data Source

PatentUS11469631B2Rotor and method of manufacturing the same

Publication Date: 2022.10.11 TOYOTA JIDOSHA KK

AI summary

A rotor that is downsized while achieving high output of the electric motor is provided. The rotor includes a plurality of main magnets and a plurality of auxiliary magnets. The auxiliary magnets are fit into a plurality of respective grooves formed along a rotation shaft direction in an outer periphery of a rotation shaft arranged at the center of the rotor, are projected from the outer periphery of the rotation shaft to an outer side of a radial direction, and have a magnetization direction along a circumferential direction of the rotor. Magnetic field directions of the auxiliary magnets that are adjacent to each other are opposite to each other in the circumferential direction. The main magnets are arranged in projected parts of the auxiliary magnets that are adjacent to each other and have a magnetization direction that is along the radial direction of the rotor.