Microstructured Insulating Sheath for Electrical Line Unrolling

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Solution Overview

Problem

Conventional electrical lines with smooth insulating sheaths experience significant adhesion and friction issues during unrolling and manufacturing, leading to problems like the 'stick slip effect' and increased energy requirements due to high flow resistance in cooling baths.

Innovation Solution

A microstructured insulating sheath with periodic depressions and elevations is created by stamping during the extrusion process, reducing friction and adhesion, and allowing for better unrolling and reduced material usage while maintaining mechanical and electrical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a smooth insulating sheath is used, then the manufacturing process is simple, but adhesion and friction increase causing stick slip effect and unrolling problems

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidunrolling performance

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The insulating sheath surface is modified with localized periodic structures (ridges and grooves) that create different friction characteristics at different locations. The grooves reduce contact area and friction with the drum surface, while the ridges maintain structural integrity. This local differentiation resolves the contradiction between smooth surface simplicity and unrolling performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Periodic curved structures (ridges and grooves) are introduced to the insulating sheath surface instead of a completely flat surface. These curved features reduce adhesion to the drum by minimizing continuous contact areas, thereby improving unrolling performance while maintaining manufacturing feasibility through extrusion molding.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Quantity of substance

If a smooth insulating sheath is used, then material usage is maximized for given dimensions, but flow resistance in cooling bath increases energy consumption

Engineering Contradiction:

Improvematerial usageVSAvoidenergy consumption

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The insulating sheath surface incorporates periodic groove structures that create a micro-channeled configuration. These grooves reduce the effective surface area in contact with the cooling bath, thereby decreasing flow resistance and energy consumption during the manufacturing process while using the same amount of material.

Inventive Principle:

Principle #31Porous materials

3Ease of operation

If a structured surface is introduced to reduce friction, then adhesion and friction decrease improving unrolling, but manufacturing complexity increases

Engineering Contradiction:

Improveunrolling performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

The microstructured surface significantly reduces adhesion and friction, improves unrolling from drums, decreases energy requirements by lowering flow resistance, and conserves material without compromising the electrical and mechanical properties of the electrical line.

Implementation Method 1

a microstructure having a plurality of stamped structural elements is formed on an outer surface of the insulating sheath... significantly reduces adhesion and friction

Methodology Applied

Scientific EffectFriction reduction through surface structuring: Friction

Implementation Method 2

the insulating sheath is applied by an extrusion method. Here, the core is pulled through an extrusion head to which a plastic synthetic melt is fed uninterruptedly

Methodology Applied

Scientific EffectExtrusion: Extrusion

Implementation Method 3

a microstructure having a plurality of stamped structural elements is formed on an outer surface of the insulating sheath... a stamping element, in particular a stamping wheel, which thus stamps the structures into the still plastic insulating sheath

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 4

downstream of the extrusion head the electrical line is pulled through a cooling bath, in particular a water bath, in order to achieve as rapid as possible a solidification of the initially viscous sheath material

Methodology Applied

Scientific EffectHeat transfer: Cooling

Data Source

PatentUS10014092B2Electrical line and method for manufacturing an electrical line

Publication Date: 2018.07.03 LEONI KABEL GMBH

AI summary

An electrical line has a core and an insulating sheath that is extruded onto the core. A structured surface having a plurality of structural elements stamped into it is formed over the entire surface of the insulating sheath. The stamped structure is a microstructure, wherein the individual structural elements have a stamping depth of at most 0.15 mm.