Conductive Overmolding for Shielded Cable Continuity

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Solution Overview

Problem

Existing methods for connecting shielded coaxial cables to metal connectors fail to ensure continuous electromagnetic shielding due to issues like incomplete wave protection, durability problems from metal separation and oxidation, and lack of waterproofing.

Innovation Solution

A method involving overmolding the junction between the cable and connector using a conductive material, ensuring a 360° ground connection by engaging the metal braid within a connector channel, utilizing a non-conductive polymer loaded with conductive particles for omnidirectional shielding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If metal envelopes are used to shield the junction between cable and connector, then electromagnetic shielding is provided, but the shielding is not completely impervious to waves, not durable over time, and not waterproof

Engineering Contradiction:
Improveelectromagnetic shielding effectivenessVSAvoiddurability and waterproofing
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses a composite material consisting of a polymer matrix loaded with conductive particles (such as metal powders, carbon black, or graphite). This composite provides both the mechanical properties of polymer (flexibility, waterproofing, durability) and the electrical conductivity needed for electromagnetic shielding. The conductive particles form a continuous conductive network within the polymer, creating an omnidirectional shield that is impervious to electromagnetic waves while being waterproof and oxidation-resistant.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the electrical conductivity parameter of the polymer material by loading it with conductive particles. The conductivity can be adjusted by varying the type, concentration, and distribution of conductive particles in the polymer matrix. This allows the material to transition from an insulator to a conductor, enabling electromagnetic shielding functionality while maintaining the beneficial mechanical properties of the polymer.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If metal braid is directly connected to metal connector, then electrical connection is established, but separation and oxidation occur over time reducing reliability

Engineering Contradiction:
Improveconnection stabilityVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent introduces a conductive polymer material as an intermediary between the metal braid and the metal connector. This intermediary layer prevents direct contact between dissimilar metals, eliminating galvanic corrosion and oxidation issues. The conductive polymer maintains electrical continuity while providing a protective barrier that prevents separation and degradation, significantly extending the service life of the connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The conductive polymer creates an inert environment between the metal braid and metal connector, preventing oxidative reactions. The polymer material is chemically stable and resistant to oxidation, effectively isolating the metal components from oxygen and moisture, thereby preventing corrosion and maintaining connection integrity over time.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Object-affected harmful factors

If conductive material overmolds the junction, then 360° ground connection and omnidirectional shielding are achieved, but manufacturing complexity increases

Engineering Contradiction:
Improveelectromagnetic shielding effectivenessVSAvoidmanufacturing process complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single material: the conductive polymer simultaneously provides mechanical protection (enveloping), electrical conductivity (ground connection), and electromagnetic shielding. This consolidation eliminates the need for separate metal envelope, grounding element, and shielding structure, simplifying the overall device architecture and manufacturing process while achieving superior omnidirectional shielding effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

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 solution provides a reliable, durable, and waterproof connection that is impervious to electromagnetic waves, preventing separation and oxidation, thus ensuring effective shielding across a wide frequency range.

Implementation Method 1

the conductive molding (5) which molds the end 3a of the cable and part of the channel of the connector (10); this overmolding is advantageously made of a conductive material described below, so as to ensure a 360° ground connection

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

Thanks to the non-conductive polymer material loaded with conductive particles, one benefits both from the enveloping and adherent properties of the material and from its conductive properties

Methodology Applied
Scientific EffectConductive particles in polymer matrix: Composite Materials

Data Source

PatentEP2676329B1Device and method for connecting a cable and a connector ensuring continuity of electromagnetic shielding
Publication Date: 2016.08.10 GETELEC
  • EP2676329B1 patent drawingFigure 1A~1D

AI summary

The invention relates to a device for joining the end (3a) of a shielded coaxial cable (3) and a metal connector (10), said cable comprising a peripheral metal braid (4) and an axial conductor (2), and comprising a conductive overmoulding (5) that at least partially surrounds the end of the shielded cable (3) and one end of said connector (10), said overmoulding making contact with said metal braid (4) and said connector (10), so as to ensure the continuity of the electromagnetic shielding of the connection. The invention also relates to a method for producing such a connection.