Stator Core Fitting Groove Relocation to Prevent Crimp Deformation

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Solution Overview

Problem

Conventional stators with laminated electrical steel sheets experience deformation in the fitting grooves due to crimping, leading to instability of insulators during coil winding, causing displacement or deformation under winding tension.

Innovation Solution

The stator design includes fitting grooves or holes on the outer peripheral side of the back yoke, positioned away from crimps, allowing projections of insulators to be securely fitted without being affected by core deformation, maintaining thickness and stability, and enhancing engagement strength through ridge-shaped raised portions that are weldable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fitting grooves are provided on outer peripheral portions of the back yoke radially outward of the crimps, then the insulators can be fixed to the stator core, but the thickness from the crimp to the outer periphery is reduced making the fitting grooves prone to deformation

Engineering Contradiction:
Improvefixing stabilityVSAvoidfitting groove deformation
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention extracts the fitting grooves from the problematic region near the crimps and relocates them to positions that are not affected by crimping deformation. Specifically, the fitting grooves are provided on the inner peripheral portion of the back yoke or on the tooth portions, separating the fitting function from the crimped region, thereby eliminating the deformation issue while maintaining fixing stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies local quality by providing fitting grooves at specific locations with different structural characteristics. The inner peripheral portion of the back yoke and the tooth portions have sufficient thickness and structural stability that is not compromised by crimping, making them suitable locations for fitting grooves that require high precision and resistance to deformation.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If fitting grooves are provided on outer peripheral portions of the back yoke, then insulators can be fixed, but the deformation due to crimps makes it difficult to fit projections into grooves and reduces fixing stability

Engineering Contradiction:
Improveinsulator fittingVSAvoidfixing stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention extracts the fitting grooves from the crimp-affected outer peripheral portions and relocates them to the inner peripheral portion of the back yoke or to the tooth portions. This separation ensures that the fitting process is not interfered with by crimping operations, making it easier to manufacture while simultaneously improving fixing stability by providing grooves in structurally stable locations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Power

If crimps are provided at positions less affected by magnetic flux, then magnetic performance is maintained, but the thickness reduction at outer periphery makes fitting grooves more prone to deformation

Engineering Contradiction:
Improvemagnetic fluxVSAvoidfitting groove deformation
Core Design Contradiction:
PowerVSManufacturing precision

Solution Approach 1:

The invention extracts the fitting grooves from the outer peripheral region where thickness reduction occurs, and relocates them to the inner peripheral portion of the back yoke or tooth portions. This allows crimps to be positioned optimally for magnetic flux while the fitting grooves are placed in regions with sufficient thickness that are not affected by crimping, thereby resolving the contradiction between magnetic performance and manufacturing precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3678285B1Stator, motor, and compressor
Publication Date: 2022.11.02 DAIKIN INDUSTRIES LTD
  • EP3678285B1 patent drawingFigure 1
  • EP3678285B1 patent drawingFigure 2
  • EP3678285B1 patent drawingFigure 3

AI summary

A stator includes a stator core (510) including a back yoke (511) having an annular shape and a plurality of teeth (512) protruding radially inward of the back yoke (511) and arranged at intervals in a circumferential direction, and insulators (520, 530) between which the stator core (510) is sandwiched from both sides in an axial direction. Fitting grooves (515) are provided on an outer peripheral side of the back yoke (511), the fitting grooves (515) extending in the axial direction and being arranged away from, in the circumferential direction, a position of a crimp (513) that joins laminated steel sheets of the back yoke (511) so as to put the position of the crimp (513) between the fitting grooves (515). Projections (524b, 534b) are provided on outer peripheral sides of insulators (520, 530), the projections (524b, 534b) being fitted into the fitting grooves (515) of the back yoke (511).