Conductive Elastomer Cable Bushing for EMC Shielding

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Solution Overview

Problem

Conventional EMC cable glands are complex and costly to manufacture and assemble due to the separation of water/dust protection and electromagnetic shielding, requiring multiple components and materials, which complicates the integration of conduit entry, dust/water protection, strain relief, and effective shielding against electromagnetic waves.

Innovation Solution

A single, at least partially electrically conductive elastomer receiving element combines dust/water protection and electromagnetic shielding, featuring a one-piece design with perforations or piercing zones that reduce the passage opening size for electromagnetic waves, eliminating the need for separate metal springs and allowing adaptation to various cable diameters, and can be integrated with a conductive frame or screw housing for secure assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional EMC cable glands use separate sealing rings and spring leaves for dust/water protection and electromagnetic shielding, then both functions are achieved, but the device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improvedust/water protection and electromagnetic shieldingVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the sealing ring and electromagnetic shielding elements into a single integrated cable gland body made of elastomer with conductive additives. The elastomer material itself provides both the sealing function through its elastic properties and the electromagnetic shielding function through its conductive characteristics, eliminating the need for separate sealing rings and spring leaves while maintaining both protective functions

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses elastomer composite materials containing conductive additives (such as carbon black, metal powders, or conductive fillers) to create a material that simultaneously possesses both sealing properties (elasticity, deformability) and electromagnetic shielding properties (electrical conductivity). This composite material approach allows a single component to fulfill multiple functions that traditionally required separate elements

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional cable glands use multiple individual elements for different functions, then each function is specialized, but the manufacturing and assembly cost increases

Engineering Contradiction:
Improvefunctional performanceVSAvoidmanufacturing and assembly cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple functional elements (sealing ring, electromagnetic shielding elements, cable grip) into a single molded elastomer component. This integration eliminates the need for assembling multiple separate parts, reducing both manufacturing complexity and assembly costs while maintaining the specialized functional performance of each element through the material's inherent properties

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The elastomer cable gland body is designed as a universal component that performs multiple functions simultaneously: sealing against dust and water, providing electromagnetic shielding, and securing the cable through frictional engagement. This multi-functional design eliminates the need for separate specialized components, reducing overall system complexity and cost

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If the receiving element is made of elastomer with conductive additives, then the material flexibility and sealing capability improve, but the electrical conductivity may be reduced compared to metal

Engineering Contradiction:
Improvesealing capability and flexibilityVSAvoidelectrical conductivity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs elastomer composite materials with conductive additives (carbon black, metal powders, conductive fillers) to achieve a balance between flexibility/sealing capability and electrical conductivity. The composite formulation is optimized to provide sufficient conductivity for electromagnetic shielding while maintaining the elastic properties needed for effective sealing and cable engagement

Inventive Principle:
Principle #40Composite materials

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 simplifies manufacturing and assembly, provides reliable shielding up to 10 GHz, and ensures strain relief while being cost-effective, adaptable to different cable diameters, and easy to install, even with pre-assembled cables, by using an elastomer with conductive additives or surface coatings for efficient sealing and shielding.

Implementation Method 1

a one-piece, at least partially electrically conductive receiving element 2 made of elastomer

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

at least partially electrically conductive receiving element 2 made of elastomer

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3574559B1Cable bushing having shielding and sealing properties
Publication Date: 2022.12.14 ICOTEK PROJEKT GMBH & CO KG
  • EP3574559B1 patent drawingFigure 1~3
  • EP3574559B1 patent drawingFigure 4

AI summary

The invention relates to a cable bushing having shielding and sealing properties for connecting to a wall provided with a break-through, comprising a sealing element and a shielding element, in which, in turn, one or more cables can be accommodated in perforations and/or penetration zones. The cable bushing according to the invention is characterized in that the sealing element and the shielding element are integrally formed of an elastomer as an at least partially electrically conductive receiving element for the at least one cable.