Divided Stator Core Geometry for Low-Cogging Torque Motors

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Solution Overview

Problem

Motors with divided stator cores face increased cogging torque due to accumulated tolerance between assembled cores, particularly when the number of cores is large, leading to deviations in open slots.

Innovation Solution

The motor design features all curvature centers of yoke outer surfaces and tooth inner surfaces being different, with specific curvature configurations and surface orientations to minimize tolerance accumulation, allowing for reduced cogging torque and streamlined manufacturing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a plurality of divided cores are assembled to constitute the stator core, then the ease of manufacture is improved, but the manufacturing precision deteriorates due to accumulated tolerance between cores

Engineering Contradiction:
Improveease of manufactureVSAvoidmanufacturing precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The stator core is divided into multiple divided cores that can be manufactured separately and then assembled. This segmentation allows for easier manufacturing of individual cores while maintaining the ability to assemble them into a complete stator core structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces asymmetric design elements such as curved surfaces with different radii of curvature on adjacent divided cores. By making the curvature centers different and using asymmetric surface profiles, the design compensates for tolerance accumulation and prevents deviation of open slots during assembly.

Inventive Principle:
Principle #4Asymmetry

2Productivity

If the number of divided cores is increased, then the ease of manufacture is improved, but the manufacturing precision deteriorates due to increased tolerance accumulation

Engineering Contradiction:
ImproveproductivityVSAvoidmanufacturing precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The stator core is divided into multiple divided cores that can be manufactured separately and then assembled. This segmentation allows for easier manufacturing of individual cores while maintaining the ability to assemble them into a complete stator core structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces asymmetric design elements such as curved surfaces with different radii of curvature on adjacent divided cores. By making the curvature centers different and using asymmetric surface profiles, the design compensates for tolerance accumulation and prevents deviation of open slots during assembly.

Inventive Principle:
Principle #4Asymmetry

3Ease of manufacture

If standard curved surfaces are used on divided cores, then the ease of manufacture is improved, but the manufacturing precision deteriorates due to slot deviation

Engineering Contradiction:
Improveease of manufactureVSAvoidmanufacturing precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention introduces asymmetric design elements such as curved surfaces with different radii of curvature on adjacent divided cores. By making the curvature centers different and using asymmetric surface profiles, the design compensates for tolerance accumulation and prevents deviation of open slots during assembly.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention changes the geometric parameters of the curved surfaces on divided cores. Specifically, it uses different radii of curvature for adjacent cores and positions curvature centers at different locations. This parameter variation compensates for manufacturing tolerances and maintains slot alignment precision.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4044402B1motor
Publication Date: 2024.02.28 LG INNOTEK CO LTD
  • EP4044402B1 patent drawingFigure 1
  • EP4044402B1 patent drawingFigure 2
  • EP4044402B1 patent drawingFigure 3

AI summary

The present invention may provide a motor including a rotating shaft, a rotor coupled to the rotating shaft, a plurality of stator cores disposed to correspond to the rotor, and a housing disposed outside the plurality of stator cores, wherein the plurality of stator cores include yokes and teeth protruding from the yokes, and curvature centers of outer surfaces of the yokes and curvature centers of inner surfaces of the teeth are eccentrically disposed with respect to a center of the stator.