Rotor Flux Concentrator Lamination Structure for Precise Polar Alignment

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Solution Overview

Problem

Existing magnetic flux concentrator structures for brushless DC motors are prone to defects during the bonding and injection molding processes, leading to reduced motor performance due to misalignment and temperature-related issues, which complicates reliable and industrializable positioning and maintenance.

Innovation Solution

A magnetic flux concentrator comprising a stack of sheets with detachable and connected polar elements, where the detachable sheets optimize magnetic properties and the connected sheets ensure precise positioning, using clips and notches for alignment and assembly, and a combination of injection molding and polarization to maintain magnetic resin integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If bonding is used to assemble the magnetic flux concentrator, then the rotor structure is formed, but defects appear and magnetic areas shift due to temperature rise

Engineering Contradiction:
Improveassembly processVSAvoidmagnetic area positioning
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The magnetic flux concentrator is divided into multiple independent polar elements that are not bonded together. Each polar element is a separate component that can be independently positioned and secured, eliminating the bonding process and its associated defects while maintaining structural integrity through mechanical interlocking.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If precise positioning is required during injection and polarization, then magnetic properties are optimized, but existing structures do not allow reliable positioning and holding

Engineering Contradiction:
Improveflux concentrator positioningVSAvoidpositioning structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The polar elements incorporate self-aligning features including protrusions that fit into recesses and notches that guide positioning during assembly. These features automatically ensure correct alignment and positioning of each polar element without requiring external positioning devices or complex holding mechanisms during injection and polarization processes.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If glue is used to assemble polar elements, then the rotor is constructed, but the glue melts at high temperature causing magnetic areas to shift

Engineering Contradiction:
Improveassembly methodVSAvoidthermal stability
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The bonding agent (glue) is completely removed from the assembly process. Instead of using adhesive to join polar elements, the design relies on mechanical interlocking through protrusions and recesses that create a thermally stable, bond-free construction capable of withstanding high operating temperatures without deformation or magnetic area shift.

Inventive Principle:
Principle #2Taking out (Extraction)

4Manufacturing precision

If polar elements are connected by a ring, then positioning is controlled, but the structure becomes more complex

Engineering Contradiction:
Improvepolar element spacingVSAvoidstructural components
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The ring structure is integrated directly into the polar elements themselves rather than being a separate component. Each polar element includes portions of the ring structure, merging the positioning function into the polar elements and eliminating the need for a distinct, separate ring component while maintaining precise spacing and alignment.

Inventive Principle:
Principle #5Merging (Combining)

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 solution facilitates reliable, easy, and industrializable positioning and maintenance of the magnetic flux concentrator, enhancing motor efficiency by minimizing defects and maintaining optimal magnetic properties during assembly and operation.

Implementation Method 1

The magnetic flux concentrator has the effect of increasing a magnetic flux of a permanent magnet of the rotor and thus maximizing a magnetic induction effect between the rotor and a stator

Methodology Applied
Scientific EffectMagnetic induction: Electromagnetic Induction

Data Source

PatentEP4128482B1Structure of a magnetic flux concentrator for a rotor for a brushless DC motor
Publication Date: 2024.01.03 DELTA DORE SA
  • EP4128482B1 patent drawingFigure 1A~1B
  • EP4128482B1 patent drawingFigure 2
  • EP4128482B1 patent drawingFigure 3~4

AI summary

Magnetic flux concentrator for a rotor, the rotor comprising a rotary shaft, the magnetic flux concentrator and magnetic regions. The magnetic flux concentrator comprises a stack of laminations (300, 400), the stack of laminations (300, 400) comprising a plurality of laminations of a first type (300) and a plurality of laminations of a second type (400), each lamination of the first type (300) comprising six polar elements which are detached from one another and each lamination of the second type comprising six polar elements (220) which are connected to one another by a ring located at the center of the lamination of the second type (400) and intended to surround the rotary shaft. The polar elements (220) of each lamination of the second type (400) are spaced regularly around the ring and each polar element (220) of one lamination (300, 400) of the stack of laminations is aligned with a polar element (220) of another lamination of the stack of laminations (300, 400) so as to form six regularly spaced stacks of polar elements (220).