Halbach Rotor Magnet Layout for Higher Motor Output Torque

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Solution Overview

Problem

Existing motors with Halbach arrays have room for improvement in terms of output torque.

Innovation Solution

A motor design featuring a rotor with a yoke and magnets arranged in a Halbach array configuration, where the first magnet is positioned opposite to the stator in the radial direction relative to the second and third magnets, with specific orientations and gaps to enhance magnetic flux density and torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a Halbach array magnet configuration is used, then magnetic flux distribution is improved, but output torque is insufficient

Engineering Contradiction:
Improvemagnetic flux distributionVSAvoidoutput torque
Core Design Contradiction:
Stability of the object's compositionVSPower

Solution Approach 1:

The rotor magnet system is segmented into multiple magnets (first magnet, second magnet, third magnet) with different orientations. Each magnet is positioned at specific radial locations with predetermined orientations, creating a segmented magnetic flux distribution pattern that improves both magnetic field stability and torque output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the rotor have different magnetic properties. The first magnet is positioned at a first radial location with a first orientation, the second magnet at a second radial location with a second orientation, and the third magnet at a third radial location with a third orientation. This local variation in magnetic quality optimizes both flux distribution and torque generation in different zones.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If magnets are arranged with different orientations in the Halbach array, then magnetic flux density is enhanced, but device complexity increases

Engineering Contradiction:
Improvemagnetic flux densityVSAvoidmagnet arrangement complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The magnet arrangement employs asymmetric orientation patterns characteristic of Halbach arrays. The magnets are oriented at different angles relative to the radial direction, creating an asymmetric magnetic flux distribution that enhances flux density on one side of the rotor while reducing it on the other, thereby improving torque without requiring complex additional components.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The magnets are pre-positioned during manufacturing with predetermined orientations and radial locations. The first magnet is set at a first orientation, the second magnet at a second orientation, and the third magnet at a third orientation before the rotor is assembled. This preliminary configuration simplifies the overall device structure while achieving the desired complex magnetic flux pattern.

Inventive Principle:
Principle #10Preliminary action

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 design improves output torque by optimizing magnetic flux distribution and density, enhancing the motor's performance.

Implementation Method 1

a plurality of magnets having different orientations of magnetic fluxes arranged at a surface of a rotor yoke

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 2

The rotor includes a yoke, and a first magnet and a second magnet arranged in a circumferential direction

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP4611221A1motor
Publication Date: 2025.09.03 MINEBEAMITSUMI INC
  • EP4611221A1 patent drawingFigure 1
  • EP4611221A1 patent drawingFigure 2
  • EP4611221A1 patent drawingFigure 3

AI summary

A motor (1) includes a shaft (2), a rotor (4), and a stator (3). The rotor (4) includes a yoke (41), and a first magnet (42a) and a second magnet (42b) arranged in a circumferential direction (C), the first magnet (42a) and the second magnet (42b) are present inside the yoke (41), and an end part (42a1) of the first magnet (42a) at an opposite side to the stator (3) is present at an opposite side to the stator (3) with respect to an end part (42b1) of the second magnet (42b) at an opposite side to the stator (3), in a radial direction (R).