Stator Winding Tooth Insulation Layout for Higher Copper Fill

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Solution Overview

Problem

Existing stator designs with tooth heads face challenges in achieving a high copper filling factor due to the need for a gap between adjacent tooth heads, which limits power density and increases cogging torque and ripple in electrical machines.

Innovation Solution

The insulation layer on the winding tooth is designed with a contour adapted to the wire diameter and winding scheme, featuring projections that act as holding devices to position the winding wire, allowing for a better filling factor by minimizing displacement forces and optimizing the winding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If tooth heads are designed with projections to reduce cogging torque and waviness, then motor ripple is reduced, but the gap between adjacent tooth heads increases, reducing the copper fill factor

Engineering Contradiction:
Improvecogging torque and motor rippleVSAvoidcopper fill factor
Core Design Contradiction:
Object-generated harmful factorsVSQuantity of substance

Solution Approach 1:

The insulation layer is pre-formed with recesses that anticipate the winding wire placement, creating holding devices that guide and secure the wire in optimal positions before winding occurs. This preliminary structuring of the insulation layer enables the wire to be positioned precisely in the grooves between tooth heads, maximizing space utilization while maintaining the tooth head projections for ripple reduction

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The insulation layer is designed with non-uniform structure - it has recesses in specific locations (at the tooth heads and between adjacent teeth) while maintaining uniform thickness in other areas. This localized variation in insulation structure allows the wire to be held securely in critical areas without increasing the overall gap between tooth heads, thus maintaining high copper fill factor while reducing cogging torque

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If a gap is left between adjacent tooth tips to allow the winding tool to fit, then winding is possible, but the copper fill factor is reduced

Engineering Contradiction:
Improvewinding processabilityVSAvoidcopper fill factor
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The insulation layer acts as an intermediary element between the tooth structure and the winding wire. Its recesses create holding devices that guide the wire into precise positions, allowing the winding tool to operate effectively in reduced spaces. The insulation protrusions fill the gaps between tooth heads, enabling tight winding spacing while maintaining manufacturability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution moves from a two-dimensional gap measurement between tooth tips to a three-dimensional utilization of space through insulation layer protrusions. The insulation extends radially outward to create holding devices that occupy the gap space, transforming the gap from a wasted space into a functional element that guides and secures the winding wire

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

3Object-generated harmful factors

If tooth heads are designed with projections to reduce cogging torque, then motor ripple is reduced, but the space available for copper winding is reduced, lowering power density

Engineering Contradiction:
Improvemotor rippleVSAvoidpower density
Core Design Contradiction:
Object-generated harmful factorsVSPower

Solution Approach 1:

The insulation layer with pre-formed recesses creates holding devices that secure the winding wire in optimal positions before the winding process completes. This ensures maximum utilization of the available winding space between tooth heads, maximizing copper fill factor and consequently power density, while the tooth head projections maintain their ripple-reducing function

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4014302B1Stator with optimized winding space
Publication Date: 2024.12.11 EBM PAPST ST GEORGEN GMBH & CO KG
  • EP4014302B1 patent drawingFigure 1
  • EP4014302B1 patent drawingFigure 2

AI summary

The invention relates to a winding tooth (1) of a stator of an electric machine, and to a stator with winding teeth of this type with a tooth tip (2) which is arranged on a tooth neck (3) and has a tooth tip end face (20), wherein the tooth tip (2) has two projections (21a, 21b) for reducing motor ripple, which projections (21a, 21b) extend laterally away from the tooth neck (3), wherein in each case one insulation layer (10a, 10b) is provided along the tooth neck (3) and the respective lateral region of the respective projection (21a, 21b), and, in the region of the tooth tip (2), the respective insulation layer (10a, 10b) forms in each case one projection (11a, 11b) extending laterally away from the tooth tip (2).