Rotor Permanent Magnet Thickness Configuration for Demagnetization Resistance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing rotor designs for rotary electric machines face challenges in demagnetization resistance and manufacturing complexity, leading to potential performance issues and increased costs due to the complexity of permanent magnet configurations and manufacturing processes.

Innovation Solution

A rotor design featuring a rotor core with radially arranged magnet insertion holes and permanent magnets with specific thickness and curvature configurations, where the radial thickness and curved longitudinal length of inner magnets are equal to or larger than those of outer magnets, and their end surfaces are aligned to minimize permeance coefficient differences, enhancing demagnetization resistance and torque capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inner permanent magnet is configured with different thicknesses at the center portion and end portions to improve demagnetization resistance, then the demagnetization resistance is improved, but the manufacturing process becomes complicated and manufacturing cost increases

Engineering Contradiction:

Improvedemagnetization resistanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by configuring the inner permanent magnet with different thicknesses at specific locations (center portion thinner, end portions thicker) to optimize magnetic flux distribution and demagnetization resistance locally where needed, rather than using a uniform thickness throughout

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent inverts the conventional design approach by making the inner permanent magnet's center portion thinner than the end portions, opposite to the typical intuition of making the center thicker for structural strength, thereby optimizing magnetic flux paths and demagnetization resistance

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

Engineering Contradiction:

Improvedemagnetization resistanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If the rotor core is provided with a rib between the permanent magnets to improve structural stability, then the structural stability is improved, but the manufacturing process becomes further complicated and manufacturing cost increases

Engineering Contradiction:

Improvestructural stabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the rotor core into multiple sections using ribs that extend from the outer circumferential surface toward the inner circumferential surface, creating distinct magnetic pole regions and improving structural stability through this segmented architecture

Inventive Principle:

Principle #1Segmentation

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 demagnetization resistance and torque capacity by reducing permeance coefficient differences between magnets, simplifying manufacturing, and optimizing magnetic flux distribution, resulting in a more robust and efficient rotary electric machine.

Implementation Method 1

a rotor (20) of a rotary electric machine (10) including: a rotor core (22) of an approximately annular shape which is formed with a plurality of sets of plural magnet insertion holes (44a, 44b)

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a reverse magnetic field is applied to the permanent magnet by a rotating magnetic field, and the reverse magnetic field acts on the permanent magnet as a demagnetizing field

Methodology Applied

Scientific EffectDemagnetization: Magnetic Field

Data Source

PatentUS11038388B2Rotor of rotary electric machine

Publication Date: 2021.06.15 HONDA MOTOR CO LTD

AI summary

A rotor of a rotary electric machine includes a rotor core of an approximately annular shape which has plural sets of plural magnet insertion holes arranged radially, the plural sets being arranged in a circumferential direction with a predetermined gap, and plural permanent magnets which are inserted into the magnet insertion holes, respectively. Each permanent magnet has a circular arc shape in a radial section, and a curved surface thereof is convex toward a rotation shaft of the rotor. Plural permanent magnets which are respectively inserted into the radially arranged plural magnet insertion holes in each set includes a first permanent magnet which is positioned on an outer circumferential surface side and a second permanent magnet which is positioned on a rotation shaft side and has a radial thickness equal to or larger than a radial thickness of the first permanent magnet.