Electric Motor Stator Guide Projections for Axial Downsizing

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Solution Overview

Problem

Conventional stators face issues with intersecting crossover wires leading to insulation peeling, increased axial length, and sizing challenges, as well as set errors during coil winding due to fixed terminal positions.

Innovation Solution

The stator design features guide projections with varying radial thickness and circumferential widths, allowing crossover wires to be extended and wound in parallel along guide sections without intersecting, reducing axial wiring areas and enabling easier coil winding with adjustable terminal positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If crossover wires are forced to intersect to reduce axial length, then axial length is reduced, but insulation peeling occurs due to vibration

Engineering Contradiction:
Improveaxial lengthVSAvoidinsulation integrity
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent transitions from a two-dimensional planar arrangement where wires must intersect to a three-dimensional arrangement using guide projections that extend radially outward. Crossover wires are routed along the outer circumferential surface of the insulator via these guide projections, allowing them to run parallel rather than intersect, thus preventing insulation peeling while maintaining compact axial dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Guide projections are introduced as intermediary structures on the insulator's outer circumferential surface. These projections provide dedicated pathways for crossover wires, acting as mediators that separate and organize the wires spatially. The guide projections prevent direct contact between crossover wires from different phases, eliminating the need for wire intersections and associated insulation risks.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If guide projections with large thickness are used to separate crossover wires, then electrical contact is prevented, but axial length increases

Engineering Contradiction:
Improveelectrical insulationVSAvoidaxial length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The guide projections feature variable cross-sectional dimensions along their length, with the radial thickness being smaller at the base and increasing toward the tip. This local quality variation provides sufficient electrical insulation at each position while minimizing the overall axial footprint. The projections are strategically positioned and dimensioned to provide just enough separation to prevent electrical contact without excessive axial length.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If terminal positions are fixed for coil winding, then winding process is simplified, but set errors occur due to positioning difficulties

Engineering Contradiction:
Improvewinding processVSAvoidterminal positioning accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The guide projections serve multiple functions: they guide the routing of crossover wires, provide electrical insulation between phases, and establish precise reference positions for terminal connections. By integrating these functions into a single structural feature, the system achieves both ease of manufacture (through unified guidance) and manufacturing precision (through consistent geometric references).

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2738916B1Stator of an electric motor comprising a coil insulation
Publication Date: 2020.10.21 YAMADA MANUFACTURING CO LTD
  • EP2738916B1 patent drawingFigure 1~2
  • EP2738916B1 patent drawingFigure 3A~4
  • EP2738916B1 patent drawingFigure 5

AI summary

A stator of an electric motor comprises: a stator core (9) with en even number of radially extending teeth (10) comprising slots (12) therebetween; an insulator (11) covering the teeth(10); and coils (13) wound around teeth (10). The insulator (11) comprises guide projections (11a) one corresponding to every tooth (10) so as to guide the coil wire (14). The guide projections (11a) comprises guide sections (11d), including a base end part (11b) and a front end part (11c). In each of the guide sections (11d), the radial thickness of at least a part of the base end part (11b) is thinner than the radial thickness of the front end part (11d). The guide sections (11d) are formed on same radial side surfaces than the guide projections (11a).