Flat-wire stator coil axial projection reduction

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Solution Overview

Problem

The existing methods for manufacturing rectangular wire stator coils result in increased axial projection of coil ends, leading to complex winding operations and higher man-hours required for assembly, especially as the number of crossed portions increases with winding pitch.

Innovation Solution

The method involves pre-forming rectangular wire elements and pieces with bent portions and using a heat conductive resin to integrate and fix them onto the stator core, reducing the axial projection and simplifying the winding process by forming sub-assemblies that can be easily assembled onto the stator core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the wire is wound around multiple teeth with extra slots, then the coil pitch increases, but the number of crossed portions increases and the axial projection length increases

Engineering Contradiction:
Improvecoil pitchVSAvoidaxial projection length
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent applies preliminary action by pre-forming stepped portions on the wire assembly before winding. The steps are created in advance at specific positions along the wire, allowing the coil ends to be positioned at different axial levels before the winding operation begins. This pre-positioning enables the wire to pass through slots and cross other coils without requiring excessive axial projection space during the actual winding process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes dimensional change by introducing axial stepped positions to manage the crossing of coils. Instead of allowing all coil ends to project equally in the axial direction, the stepped portions create different axial levels (z-dimension) for different sections of the wire assembly. This dimensional differentiation allows coils to cross each other in a controlled manner while limiting the maximum axial projection length.

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

2Adaptability or versatility

If the coil ends are crossed to accommodate higher pitch windings, then the winding adaptability improves, but the winding operation complexity increases

Engineering Contradiction:
Improvewinding pitch flexibilityVSAvoidwinding operation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent reduces winding operation complexity by performing preliminary actions of forming stepped portions and pre-arranging the wire assembly geometry before the actual winding process. The stepped portions are created in advance at calculated positions, and the wire assembly is pre-configured with these steps, so that during winding, the operator simply needs to follow the pre-determined path through slots and across coils, rather than manually managing complex crossings in real-time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies segmentation by dividing the wire assembly into multiple sections with different stepped positions. Each section of the wire assembly has specifically positioned steps that correspond to different slot positions and crossing points. This segmentation allows the complex winding pattern to be broken down into manageable, pre-planned segments that can be executed systematically rather than as a single complex operation.

Inventive Principle:
Principle #1Segmentation

3Length of stationary object

If conventional weaving methods are used to suppress axial projection, then the axial length is reduced, but the manufacturing complexity increases

Engineering Contradiction:
Improveaxial projection lengthVSAvoidmanufacturing complexity
Core Design Contradiction:
Length of stationary objectVSEase of manufacture

Solution Approach 1:

The patent eliminates the need for complex post-winding weaving operations by performing preliminary action of creating stepped portions on the wire assembly before winding. The steps are formed in advance at positions that pre-determine the axial projection of different coil ends, allowing the axial length to be controlled inherently by the geometry of the wire assembly rather than requiring additional weaving operations after winding is complete.

Inventive Principle:
Principle #10Preliminary action

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 approach reduces the axial projection of coil ends and significantly decreases the man-hours needed for coil winding, enhancing production efficiency and heat dissipation properties while preventing electric short circuits.

Implementation Method 1

using a heat conductive resin to integrate and fix them onto the stator core

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP3154159B1Flat-wire stator coil manufacturing method
Publication Date: 2020.05.06 NISSAN MOTOR CO LTD
  • EP3154159B1 patent drawingFigure 1A~1B
  • EP3154159B1 patent drawingFigure 2
  • EP3154159B1 patent drawingFigure 3~4

AI summary

A rectangular wire is wound on a stator core having a plurality of teeth and a plurality of slots. A plurality of rectangular wire elements is provided by cutting a rectangular wire into a predetermined length and bending into a substantial U-shape. A plurality of rectangular wire pieces configured to form a coil by connecting predetermined end portions of the rectangular wire elements is molded as a sub-assembly. Each of the plurality of the rectangular wire elements is inserted into a predetermined pair of the slots from a first end face of the stator core such that the respective end portions of the rectangular wire elements project from a second end face of the stator core. The rectangular wire pieces of the sub-assembly are fixed to the end portions of the rectangular wire elements, thereby manufacturing a stator coil having compact coil ends easily.