Flexible Strip Magnet Assembly for Electric Motors

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Solution Overview

Problem

The geometry of rotor or stator carcasses in electric motors makes it difficult to precisely position and fix magnets, especially permanent magnets, which complicates the manufacturing process and operator safety.

Innovation Solution

A flexible strip with ferromagnetic elements and spacers is used, allowing for easier positioning and fixing of magnets on the strip before assembly onto the motor components, with magnetization occurring only at the final stage, and using bonding methods like UV polymerization for secure attachment without altering the mechanical or electromagnetic structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If magnets are fixed one by one directly on the rotor or stator carcass, then precise positioning can be achieved, but the manufacturing process becomes complex and operator safety is compromised due to difficult geometry adaptation and magnet handling

Engineering Contradiction:
Improvemagnet positioning precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention divides the magnet fixation process into two independent stages: first fixing magnets to a flexible strip on a flat work surface, then assembling the pre-assembled strip to the rotor or stator carcass. This segmentation separates the precision positioning operation from the complex geometry adaptation, allowing each to be optimized independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible strip with magnets is prepared in advance on a flat work surface before being assembled to the final component. This preliminary action allows precise positioning to be performed under optimal conditions (flat surface, easy access) rather than attempting to position magnets directly on the complex 3D geometry of the rotor or stator during final assembly.

Inventive Principle:
Principle #10Preliminary action

2Use of energy by moving object

If permanent magnets are used, then optimal electrical to mechanical energy conversion is achieved, but handling becomes difficult due to magnetization during fixing

Engineering Contradiction:
Improveenergy conversion efficiencyVSAvoidmagnet handling ease
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The flexible strip with ferromagnetic elements is prepared in advance before magnetization. By performing the positioning and fixation operations on unmagnetized elements first, then magnetizing them afterward, the invention eliminates handling difficulties while still achieving the desired permanent magnet configuration for optimal energy conversion.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the magnetic state parameter of the ferromagnetic elements from unmagnetized during assembly to magnetized after assembly. This parameter change timing resolves the contradiction by ensuring magnets are easy to handle during positioning (unmagnetized state) while still achieving optimal energy conversion (magnetized state in final position).

Inventive Principle:
Principle #35Parameter changes

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 improves operator comfort and safety, allows for the use of different types of magnets with the same assembly, reduces manufacturing time and costs, and enables flexible manufacturing of various electric motor types, while maintaining the mechanical and electromagnetic integrity of the motor.

Implementation Method 1

the ferromagnetic elements form permanent magnets

Methodology Applied
Scientific EffectMagnetization: Magnetism

Implementation Method 2

The flexible strip is provided with fastening means, for example with at least one adhesive

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 3

using bonding methods like UV polymerization for secure attachment

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP3396822A1Braking system comprising magnets
Publication Date: 2018.10.31 ASTEMO FRANCE
  • EP3396822A1 patent drawingFigure 1~2
  • EP3396822A1 patent drawingFigure 3~5
  • EP3396822A1 patent drawing

AI summary

The assembly (1) comprises: - a flexible strip (2) having a first face and a second face, and - ferromagnetic elements (4) fixed to one of said faces of the strip (2). The assembly is in a configuration such that at least a part of one of said faces of the strip is suitable for being directly attached to a support.