Permanent Magnet Rotor Assembly via Pre-Assembly and Rotation

Solution Overview

Problem

The assembly of large electric machines with permanent magnets is costly and risky due to high magnetic attraction forces between the rotor and stators, making it difficult to insert and separate the components without damaging the magnets.

Innovation Solution

A method and installation for assembling electric machines where the stators and rotor are pre-assembled without magnets, allowing for the sequential insertion of magnets into pre-arranged locations using rotation and insertion tooling, reducing magnetic interaction forces and improving safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the rotor is completely lined with magnets before assembly, then the magnetic field strength is maximized, but the magnetic attraction forces become uncontrollably high making assembly dangerous and costly

Engineering Contradiction:

Improvemagnetic field strengthVSAvoidassembly safety

Core Design Contradiction:

PowerVSEase of operation

Solution Approach 1:

The rotor is pre-assembled with magnets in a controlled environment before final assembly with stators. This preliminary action allows magnets to be positioned and secured without exposing operators to the full magnetic forces that would exist during final assembly, thus maintaining magnetic field strength while improving assembly safety

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The assembly process is divided into separate stages: first assembling the rotor with magnets independently, then separately positioning stators, and finally combining them. This segmentation allows magnetic forces to be managed in controlled portions rather than all at once, reducing immediate operational hazards

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If all magnets are positioned on the rotor before final assembly, then the magnetic forces are difficult to control, but the assembly process becomes simpler

Engineering Contradiction:

Improveassembly process simplicityVSAvoidmagnetic force control

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The rotor is pre-assembled with magnets in a controlled environment before final assembly with stators. This preliminary action allows magnets to be positioned and secured without exposing operators to the full magnetic forces that would exist during final assembly, thus maintaining magnetic field strength while improving assembly safety

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A non-magnetic temporary support structure or tooling is used during the magnet positioning process to mediate between the magnets and the final assembly fixtures. This intermediary allows magnets to be positioned without immediately engaging the full magnetic attraction to stators, providing control over magnetic forces while maintaining assembly simplicity

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If the rotor and stators are assembled with a small empty space between them, then the machine design is optimized, but the risk of magnet damage increases during assembly

Engineering Contradiction:

Improvespacing precisionVSAvoidmagnet integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The rotor is pre-assembled with magnets in a controlled environment before final assembly with stators. This preliminary action allows magnets to be positioned and secured without exposing operators to the full magnetic forces that would exist during final assembly, thus maintaining magnetic field strength while improving assembly safety

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Magnetic shims or non-magnetic spacers are pre-positioned between the rotor and stators during the pre-assembly phase to cushion against excessive magnetic attraction forces. This beforehand cushioning protects magnets from damage while ensuring the final small empty space spacing is achieved in the completed assembly

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 method simplifies the assembly process, reduces the risk of magnet damage and operator accidents, and lowers the risk of equipment damage by controlling magnetic forces during the insertion of large and powerful magnets.

Implementation Method 1

very high magnetic attraction forces are created between the rotor completely lined with magnets and the stators

Methodology Applied

Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentEP2571148B1Montageverfahren einer Elektromaschine mit Dauermagneten

Publication Date: 2019.10.30 GE RENEWABLE TECH

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AI summary

The method involves pre-assembling circular stators and a disk shaped rotor (10) deprived of permanent magnets, where the rotor includes a set of pre-arranged positions (24) to a receive permanent magnet (26). A rotation unit i.e. bearing, is installed to rotate the rotor so as to bring the pre-arranged position devoid of permanent magnet in correspondence with a predetermined fixed space insertion position (28). The permanent magnet is inserted in the pre-arranged position of the rotor in correspondence with the predetermined space insertion position. An independent claim is also included for an installation for assembling a permanent magnet electric machine.