Rotor Magnet Fixing via Joule Heating

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional methods for manufacturing rotors in rotating electric machines require heating a large thermal capacity rotor core and fixing member, necessitating a large heating furnace and significant time and energy.

Innovation Solution

A method where an electric current is applied to the magnet through electrodes to heat the fixing member, eliminating the need for a heating furnace and reducing heating time and energy by using the magnet's electrical resistance to fix it to the rotor core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a heating furnace is used to heat the fixing member and rotor core, then the magnet can be fixed to the rotor core, but the heating process requires large time and energy consumption

Engineering Contradiction:

Improvefixing reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the heating function from the large-scale heating furnace and concentrates it locally at the magnet level. By applying current directly to the magnet, heat is generated only where needed (at the magnet and fixing member interface), eliminating the need for furnace-based heating of the entire rotor core while maintaining reliable fixing.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The magnet serves dual functions: it provides the magnetic field function and simultaneously acts as a heating element through its electrical resistance. When current passes through the magnet, it generates heat that fixes the fixing member, allowing the magnet to serve itself for both its primary function and the heating requirement.

Inventive Principle:

Principle #25Self-service

2Reliability

If a heating furnace is used to heat the fixing member and rotor core, then the magnet can be fixed to the rotor core, but the heating process requires large time consumption

Engineering Contradiction:

Improvefixing reliabilityVSAvoidheating time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The heating function is extracted from the furnace and localized to the magnet. This localized heating approach heats only the fixing member and magnet interface rather than the entire rotor core, dramatically reducing heating time while ensuring reliable fixing at the critical interface.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The thermal field is generated electrically through Joule heating of the magnet when current passes through it. This electrical heating method replaces the furnace-based thermal field, providing faster and more controlled heating that reduces processing time while maintaining fixing reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a large-sized heating furnace is used to heat the rotor core and fixing member, then the magnet can be fixed to the rotor core, but the equipment size and complexity increase

Engineering Contradiction:

Improvefixing reliabilityVSAvoidheating equipment complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The heating function is extracted from the complex furnace system and integrated directly into the magnet. This eliminates the need for large heating equipment, reducing device complexity while maintaining the ability to reliably fix the magnet to the rotor core through localized heating.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The magnet generates its own heat through electrical resistance when current passes through it, eliminating the need for external heating equipment. This self-heating capability simplifies the overall system by removing the furnace and associated control systems while ensuring reliable fixing.

Inventive Principle:

Principle #25Self-service

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 approach allows for efficient heating of the fixing member without a furnace, reducing energy consumption and time, while ensuring appropriate temperature control to prevent fixing failures and deterioration of the rotor core and magnet.

Implementation Method 1

applying an electric current to the at least one magnet through electrodes brought in contact with opposite end portions of the at least one magnet, so as to heat the at least one fixing member by heat generated by an electrical resistance of the at least one magnet

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11716000B2Method for manufacturing rotor for rotor electric machine

Publication Date: 2023.08.01 TOYOTA JIDOSHA KK

AI summary

A method of manufacturing a rotor for a rotating electric machine. The rotor includes a rotor core and at least one magnet fixed in at least one magnet fixing portion provided in the rotor core. The method includes: (a) placing the at least one magnet and at least one fixing member in the at least one magnet fixing portion such that each of the at least one fixing member is positioned between a corresponding one of the at least one magnet fixing portion and a corresponding one of the at least one magnet; and (b) applying an electric current to the at least one magnet to heat the at least one fixing member by heat generated by an electrical resistance of the at least one magnet, and fixing the at least one magnet to the at least one magnet fixing portion through the heated at least one fixing member.