Stacked Ceramic Magnet Rotor for High Flux Density

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Solution Overview

Problem

High efficiency rotary electric machines rely on expensive and supply-limited rare earth magnets, while cost-effective ceramic magnets with lower magnetic properties are readily available but not utilized effectively for enhanced performance.

Innovation Solution

A magnet configuration that concentrates lower strength ceramic magnets into high flux density by separating the rotor into layers with flat disc-shaped magnets and magnetically soft material, using alternating integral tabs and magnetic separators to prevent flux shorting, and attaching the sections with non-magnetic spacers or shafts for enhanced performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If rare earth magnets are used, then high efficiency and high magnetic properties are achieved, but cost increases and supply limitations occur

Engineering Contradiction:

ImproveefficiencyVSAvoidcost

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The rotor is divided into multiple stacked sections, each containing magnet segments. This segmentation allows the use of lower-cost ceramic magnets while achieving high overall performance through the cumulative effect of multiple sections working together in series.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite construction with magnet segments, magnetic separators, and non-magnetic structural components. This composite approach enables the use of cost-effective ceramic magnets while maintaining high efficiency through optimized magnetic circuit design.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If ceramic magnets are used, then cost decreases and availability improves, but magnetic properties and flux density are reduced

Engineering Contradiction:

ImprovecostVSAvoidefficiency

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The invention transitions from using fewer high-strength magnets to stacking multiple sections with lower-strength ceramic magnets. By extending the magnetic circuit in the axial dimension, the design achieves high flux density through cumulative effect rather than relying on individual magnet strength.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Multiple magnet sections are combined in series along the axial direction, with each section contributing to the overall flux density. The merging of these sections creates a cumulative magnetic effect that compensates for the lower individual magnet strength.

Inventive Principle:

Principle #5Merging (Combining)

3Use of energy by moving object

If rotor is separated into stacked sections, then flux density is enhanced and performance improves, but device complexity increases

Engineering Contradiction:

ImproveefficiencyVSAvoidstructure

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The rotor is segmented into multiple identical or similar sections that can be manufactured separately and then assembled. This segmentation improves manufacturability and allows for modular assembly, reducing the practical complexity despite the increased number of components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each stacked section serves multiple functions: it provides magnetic flux paths, structural support, and thermal management. The magnetic separators simultaneously prevent flux shorting and provide mechanical spacing, reducing the need for separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Use of energy by moving object

If magnetic separators are added between tabs, then flux shorting is prevented and magnetic performance is maintained, but manufacturing complexity increases

Engineering Contradiction:

ImproveefficiencyVSAvoidmanufacturing

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

Magnetic separators are introduced as intermediary components between adjacent magnetic tabs. These separators act as flux barriers that prevent unwanted flux paths while maintaining the overall magnetic circuit efficiency. The separators are simple disc-shaped components that are easy to manufacture and position.

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 enhances the performance of rotary electric machines by achieving high flux density and maintaining structural integrity, effectively utilizing lower strength ceramic magnets for improved efficiency.

Implementation Method 1

magnetic separators between alternating tabs to prevent flux from shorting between poles

Methodology Applied

Scientific EffectMagnetic field blocking: Magnetic Field

Implementation Method 2

concentrates the lower strength magnets into high flux density in the airgap

Methodology Applied

Scientific EffectMagnetism: Magnetism

Data Source

PatentUS8878411B2High efficiency permanent magnet machine with separated tab pole rotor and stacked ceramic magnet sections

Publication Date: 2014.11.04 LC ADVANCED MOTOR TECHNOLOGY CORP

AI summary

A permanent magnet motor, generator or the like that uses ceramic magnets in the rotor to concentrate the magnetic flux in the airgap. Poles are formed by pole plates with integral tabs forming north and south poles with magnetic separators therebetween. Magnet sections are stacked axially.