Rotary Machine Laminated Core Rectilinear Pressing

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Solution Overview

Problem

Conventional rotary electric machine laminated cores experience efficiency reduction and increased torque pulsation due to shape accuracy issues and machining strain, and the lancing method generates scrap and damages pressing dies during core segment assembly.

Innovation Solution

The laminated core design includes notch portions near rotating shafts and a gap between adjacent projecting and recess portions, allowing for rectilinear pressing without lancing, reducing machining strain and scrap generation, and improving material yield and productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the lancing method is used to form interfitting contacting portions of core segments, then the core segments can be coupled together, but warping arises in portions corresponding to the bending fulcrum of lancing, reducing shape accuracy and increasing torque pulsation

Engineering Contradiction:
Improvecore segment assemblyVSAvoidshape accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The core segments are divided into multiple parts with projecting portions and recess portions that can be assembled together. This segmentation allows each part to be manufactured separately with better precision control, avoiding the warping issues that occur when trying to form interfitting portions in a single piece through lancing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The projecting portions and recess portions are extracted as separate features from the core segment body. By pre-forming these interfitting features as distinct elements and then assembling them, the patent avoids the warping problems associated with forming these features through lancing operations on the main core segment structure.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If the lancing method is used to form interfitting contacting portions, then core segments can be coupled, but machining strain increases and efficiency is reduced

Engineering Contradiction:
Improvecore segment couplingVSAvoidmachining strain
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The projecting portions and recess portions are pre-formed on the core segments before final assembly. This preliminary formation of interfitting features eliminates the need for high-strain lancing operations during assembly, as the coupling features are already prepared in advance with minimal machining strain.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If the lancing method is used for core segment assembly, then core segments can be joined, but scrap is generated and pressing die damage occurs

Engineering Contradiction:
Improvecore segment joiningVSAvoidscrap generation
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

By segmenting the core into multiple parts with projecting and recess portions, the patent enables assembly without lancing operations. This eliminates the scrap generation and pressing die damage that occur when lancing is used to form interfitting portions, as the coupling features are formed as separate elements rather than through material removal.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2557660B1Layered iron core of rotary electrical machine
Publication Date: 2019.03.06 MITSUBISHI ELECTRIC CORP
  • EP2557660B1 patent drawingFigure 1~2
  • EP2557660B1 patent drawingFigure 3
  • EP2557660B1 patent drawingFigure 4~5

AI summary

In a rotary electric machine laminated core, a rotating shaft portion is disposed closer to an outer circumferential surface than an inner circumferential surface of a back yoke portion. A notch portion is disposed on at least one of first and second end portions of the back yoke portion so as to form a gap between a vicinity of the rotating shaft portion of a projecting portion and a recess portion when core segments are arranged in an annular shape or a circular arc shape. The first end portion and the second end portion of the back yoke portion are configured such that a predetermined gap that connects from the outer circumferential side to the inner circumferential side is formed between adjacent projecting portions and recess portions when the core segments are expanded rectilinearly such that magnetic pole tooth portions are parallel to each other.