Superconducting Wire Cover with Differential Surface Roughness

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Solution Overview

Problem

Conventional superconducting wires experience deterioration of superconducting characteristics due to stress caused by heat shrinkage differences between the wire and the impregnating resin when cooled, leading to potential damage to the superconducting material layer.

Innovation Solution

A superconducting wire design with a cover portion having smaller surface roughness in the central portion than at the ends, which reduces adhesiveness between the cover and resin in the central area, allowing stress release through peeling and minimizing damage to the superconducting material layer, while maintaining high thermal conductivity by suppressing peeling at the ends.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cover portion has high surface roughness to improve adhesiveness with resin, then the bonding strength between cover and resin increases, but stress concentration occurs in the central portion causing damage to the superconducting material layer

Engineering Contradiction:

Improvebonding strength between cover and resinVSAvoidstress concentration on superconducting material layer

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies different surface roughness values to different regions of the cover portion: the central portion has a first surface roughness value optimized for stress distribution, while the end portions have a second surface roughness value optimized for bonding strength. This local differentiation allows each region to perform its specific function without compromising the other.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cover portion is segmented into functional zones based on surface roughness characteristics. The central portion and end portions are treated as distinct segments with different surface properties, allowing independent optimization of stress management and bonding functions.

Inventive Principle:

Principle #1Segmentation

2Strength

If the cover portion has high surface roughness to improve bonding with resin, then adhesion increases, but peeling occurs at the central portion leading to stress application on the superconducting wire

Engineering Contradiction:

Improveadhesion between cover and resinVSAvoidsuperconducting characteristics

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

Different surface roughness values are assigned to different locations on the cover portion. The central portion has a first surface roughness that prevents excessive peeling while allowing stress release, and the end portions have a second surface roughness that ensures strong bonding. This local quality differentiation resolves the contradiction between adhesion and reliability.

Inventive Principle:

Principle #3Local quality

3Reliability

If the cover portion has low surface roughness to reduce stress, then the superconducting material layer is protected from damage, but adhesiveness between the cover and resin decreases

Engineering Contradiction:

Improvesuperconducting characteristicsVSAvoidbonding strength between cover and resin

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent implements location-dependent surface roughness on the cover portion. The central portion has a first surface roughness optimized for stress reduction and superconducting material protection, while the end portions have a second surface roughness optimized for bonding strength. This resolves the contradiction by assigning different quality characteristics to different spatial locations.

Inventive Principle:

Principle #3Local quality

4Ease of manufacture

If uniform surface roughness is applied across the cover portion, then manufacturing is simplified, but both bonding strength and stress management cannot be optimized simultaneously

Engineering Contradiction:

Improvecover portion fabricationVSAvoidsuperconducting characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Rather than using uniform surface roughness, the patent applies different surface roughness values to different regions of the cover portion. This local differentiation allows simultaneous optimization of bonding strength at the ends and stress management in the center, achieving both reliability and manufacturability through targeted surface engineering.

Inventive Principle:

Principle #3Local quality

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 design effectively suppresses the deterioration of superconducting characteristics and enhances cooling efficiency by managing stress and heat transfer in superconducting coils.

Implementation Method 1

surface roughness in a central portion in a width direction of the superconducting wire is smaller than surface roughness at an end portion in the width direction

Methodology Applied

Scientific EffectStress concentration:

Data Source

PatentUS10490321B2Superconducting wire and superconducting coil

Publication Date: 2019.11.26 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

A superconducting wire includes a main body portion, a substrate, and a cover portion. The main body portion includes a first main surface and a second main surface located opposite to the first main surface, and includes a superconducting material portion. The substrate supports the second main surface of the main body portion. The cover portion is formed at least on the first main surface of the main body portion. In the cover portion, surface roughness in a central portion in a width direction of the superconducting wire is smaller than surface roughness at an end portion in the width direction.