End Ring Element for Coil Devices with Adjustable Stiffness

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Solution Overview

Problem

The conventional production of end rings for coil devices in high-voltage/high-power applications is costly due to significant material scrap and requires specialized tools, as each diameter requires a separate cylinder for cutting, leading to inefficient use of resources and complex manufacturing processes.

Innovation Solution

The development of end ring elements formed from sheet material with a trapezoidal shape and flexible portions, allowing for bending into a cylindrical shape, which provides stiffness in the width direction and flexibility in the longitudinal direction, enabling the creation of end rings with adjustable thickness and length to fit various winding diameters, reducing scrap and simplifying tooling requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional cylinders are cut to produce end rings for each different diameter, then the end rings can be precisely fitted to the winding layers, but a large fraction of the cylinder material becomes scrap and special expensive tools are required

Engineering Contradiction:
Improveend ring fit precisionVSAvoidcylinder material scrap
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The end ring is segmented into a first end ring portion and a second end ring portion that can be separately formed and then joined together. This allows the end ring to be constructed from smaller, more efficiently utilized material pieces rather than cutting from a large cylinder, reducing scrap material while maintaining precise fit to the winding layer.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of producing end rings by cutting from cylindrical stock in three dimensions, the invention forms end rings by joining two flat or curved portions that can be manufactured from sheet material or by winding. This dimensional change from volumetric stock removal to surface-based construction significantly reduces material waste.

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

2Manufacturing precision

If conventional cylinders are cut to produce end rings for each different diameter, then the end rings can be precisely fitted to the winding layers, but special and expensive tools and equipment are required

Engineering Contradiction:
Improveend ring fit precisionVSAvoidtooling complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By dividing the end ring into two portions that can be formed separately and joined, the manufacturing process avoids the need for specialized large-diameter cutting tools. Each portion can be manufactured using simpler, more versatile equipment, and the joining process is more straightforward than precision cutting of solid cylinders.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of cutting the end ring from a solid cylinder (subtractive manufacturing), the invention builds the end ring by joining two portions (constructive manufacturing). This inversion of the manufacturing approach eliminates the need for expensive cutting tools and reduces material removal requirements.

Inventive Principle:
Principle #13The other way round (Inversion)

3Manufacturing precision

If end rings are made with varying thickness to match winding layer thickness, then the end face becomes even for homogeneous pressure application, but the manufacturing complexity increases

Engineering Contradiction:
Improveend face flatnessVSAvoidend ring structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The end ring is divided into two portions where the thickness variation is achieved more simply. One portion can have a relatively uniform thickness while the other compensates for the winding layer thickness variation, or both portions can be formed with simpler thickness profiles that combine to achieve the required end face flatness.

Inventive Principle:
Principle #1Segmentation

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 solution allows for the production of end rings with reduced material waste, simpler tooling, and adaptable dimensions, ensuring effective compacting of coil windings while minimizing axial forces during short circuits, thus enhancing the mechanical integrity and versatility of coil devices.

Implementation Method 1

The plane band has a cross-section along the longitudinal direction having flexible portions which allow a bending to a ring along the longitudinal direction and having spacing portions between the flexible portions providing the constant spacing capability

Methodology Applied
Scientific EffectFlexibility and stiffness through geometric structure:

Implementation Method 2

the plane band can have a cross-section along the longitudinal direction having a corrugated structure, wherein the corrugated structure has corrugation elements extending along the width direction, thereby providing stiffness along the width direction

Methodology Applied
Scientific EffectCorrugation structure providing stiffness: Corrugation

Data Source

PatentEP3014636B1Method for producing a coil device, an end ring element and a coil device having an end ring element
Publication Date: 2018.05.09 ABB (SCHWEIZ) AG
  • EP3014636B1 patent drawingFigure 1
  • EP3014636B1 patent drawingFigure 2~4
  • EP3014636B1 patent drawingFigure 5

AI summary

The present invention relates to an end ring element (10) for forming an end ring (5) for a coil device (1), wherein the end ring element (10) is formed by a plane band which extends along a longitudinal direction (L) and a width direction (W), wherein the band provides a constant spacing capability over its length along the longitudinal direction (L); and a higher stiffness in the width direction (W) than in the longitudinal direction (L).