Interior Permanent Magnet Motor Rotor Demagnetization Resistance

Solution Overview

Problem

Conventional interior permanent magnet motors experience a decline in magnetic force due to demagnetization, particularly at the outer circumferential ends, leading to reduced efficiency and motor performance issues.

Innovation Solution

The rotor design includes magnet insertion pockets with openings only at the inner circumferential face, excluding both ends, to prevent demagnetization by reducing the area susceptible to demagnetization and maintaining magnetic force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If openings are provided at the ends of permanent magnets to suppress demagnetization, then demagnetization resistance is improved, but magnetic force declines leading to reduced efficiency

Engineering Contradiction:

Improvedemagnetization resistanceVSAvoidmagnetic force

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention applies local quality by providing openings only at specific locations (outer circumferential sides of the magnet insertion pockets) rather than uniformly at all ends of permanent magnets. This localized approach targets the areas most susceptible to demagnetization while preserving the magnetic force in other critical regions, thus resolving the contradiction between demagnetization resistance and magnetic force maintenance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention segments the magnet insertion pocket structure by introducing openings only at the outer circumferential sides, dividing the protection strategy into specific zones. This segmentation allows demagnetization suppression at vulnerable outer edges while maintaining continuous magnetic paths in the inner regions, preventing overall magnetic force decline.

Inventive Principle:

Principle #1Segmentation

2Reliability

If openings are provided at both ends of permanent magnets, then demagnetization is suppressed, but the magnetic force declines due to reduced magnetic path area

Engineering Contradiction:

Improvedemagnetization resistanceVSAvoidmagnetic force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The invention applies local quality by providing openings only at specific locations (outer circumferential sides of the magnet insertion pockets) rather than uniformly at all ends of permanent magnets. This localized approach targets the areas most susceptible to demagnetization while preserving the magnetic force in other critical regions, thus resolving the contradiction between demagnetization resistance and magnetic force maintenance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention applies partial action by providing openings only at the outer circumferential sides of magnet insertion pockets rather than at all ends of permanent magnets. This partial approach is sufficient to suppress demagnetization at the most vulnerable locations without excessively reducing the overall magnetic path area, thereby maintaining magnetic force.

Inventive Principle:

Principle #16Partial or excessive 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

This design effectively prevents a decline in magnetic force and enhances resistance to demagnetization, maintaining motor efficiency and performance.

Implementation Method 1

a permanent magnet (2-1 to 2-6) generating a magnetic field

Methodology Applied

Scientific EffectMagnetism: Magnetism

Implementation Method 2

the magnet insertion pocket is formed so as to provide a space in an area except both ends of an inner circumferential face, at both ends in a circumferential direction of the permanent magnet

Methodology Applied

Scientific EffectDemagnetization resistance:

Data Source

PatentUS9276445B2Rotor and interior permanent magnet motor

Publication Date: 2016.03.01 MITSUBISHI ELECTRIC CORP

AI summary

A rotor, constituting an interior permanent magnet motor, includes magnets that are inserted into the rotor, and a rotor core containing magnet insertion pockets to which the magnets are inserted, and, when the magnets are inserted, the magnet insertion pockets are formed to provide openings in areas except both ends of an inner circumferential face, at both ends in a circumferential direction of the magnets.