Electric Motor Rotor Air Gap Insulation Design

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Solution Overview

Problem

Existing electric motor rotors with 'buried' magnets require insulating materials on each face of the magnets, increasing manufacturing costs and complicating assembly processes while not fully satisfying magnetic properties.

Innovation Solution

The electric motor rotor design eliminates the need for insulating materials by using a laminated assembly with notches and intermediate zones to house permanent magnets, allowing for air gaps between them, which simplifies assembly and reduces costs by using less expensive magnets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If insulating material is added on each face of the permanent magnets, then the magnets are insulated from each other and from the laminated assembly, but the manufacturing cost increases and the assembly process becomes complicated

Engineering Contradiction:
Improvemagnetic insulationVSAvoidassembly process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the insulation function into the housing structure itself. The housing forms air gaps between adjacent magnets and between magnets and the laminated assembly, eliminating the need for separate insulating materials. This integration simplifies the assembly process while maintaining magnetic insulation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces air gaps as an intermediary medium between the permanent magnets and the laminated assembly. These air gaps serve as natural magnetic insulators, replacing the need for additional insulating materials and simplifying the overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If insulating material is added on each face of the permanent magnets, then the magnets are insulated from each other, but the manufacturing cost increases

Engineering Contradiction:
Improvemagnetic insulationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The insulation function is merged into the housing design. The housing structure itself creates air gaps that provide magnetic insulation, eliminating the need for additional insulating materials and reducing manufacturing costs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses air gaps instead of expensive insulating materials. Air is a free, naturally occurring substance that effectively provides magnetic insulation without adding material cost to the manufacturing process.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If magnets are placed in housings without insulating material, then assembly is simplified, but magnetic flux short-circuits may occur between adjacent magnets

Engineering Contradiction:
Improveassembly simplicityVSAvoidmagnetic flux isolation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Air gaps are introduced as intermediary spaces between adjacent magnets within the same housing. These air gaps prevent magnetic flux short-circuits while maintaining the simplicity of the housing structure and assembly process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The housing is segmented to create separate compartments or air gaps between adjacent magnets. This segmentation isolates the magnetic flux paths of individual magnets, preventing short-circuits while keeping the overall structure simple.

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

This design maintains satisfactory magnetic properties, reduces manufacturing costs, and facilitates quick assembly by avoiding the need for additional insulating materials, while minimizing contact between magnets to maintain high motor efficiency.

Implementation Method 1

The electric motor rotor design eliminates the need for insulating materials by using a laminated assembly with notches and intermediate zones to house permanent magnets, allowing for air gaps between them

Methodology Applied
Scientific EffectAir gap insulation:

Implementation Method 2

magnetic elements 4 in the form of permanent magnets, distributed over the inner periphery of the laminated assembly

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

electric motor rotor comprising a body of substantially cylindrical shape, magnetic field conductor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3057201B1Electric motor rotor and electric motor associated
Publication Date: 2022.08.03 ALSTOM TRANSPORT TECH SAS
  • EP3057201B1 patent drawingFigure 1
  • EP3057201B1 patent drawingFigure 2
  • EP3057201B1 patent drawingFigure 3

AI summary

The present invention relates to a rotor (2) of an electric motor (1) comprising a body (6) of substantially cylindrical shape, conducting a magnetic field, delimiting at least one housing (12) receiving a group of magnets (4) comprising at least two permanent magnets (4). The two magnets (4) circumferentially adjacent to the housing (12) are separated from each other by an air gap (24).