Conductive Seal Assembly for EMI Shielding in Plastic Housings
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Solution Overview
Problem
Existing sealing arrangements in the field of 'e-mobility' face challenges in using lightweight materials for electromagnetic shielding, as plastics with electrically insulating spray skins hinder conductive connections, leading to ineffective interference wave shielding.
Innovation Solution
A sealing arrangement featuring electrically conductive machine elements, with a support body having thorn-shaped projections that penetrate the insulating spray skin for reliable electrical contact and electromagnetic interference shielding, utilizing electrically conductive plastics and metallic materials for reduced weight and effective shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If lightweight materials like electrically conductive plastics are used for machine elements, then weight is reduced, but electromagnetic shielding effectiveness deteriorates due to electrically insulating injection-molded skins
Solution Approach 1:
The seal is divided into functionally distinct components: an electrically conductive support body with mandrel-shaped projections and an electrically insulating sealing material. This segmentation allows the conductive projections to penetrate the insulating injection-molded skin and establish electrical contact between machine elements, while the sealing material maintains the sealing function. The segmentation resolves the contradiction by separating the electrical conduction path from the overall insulating structure.
Solution Approach 2:
The seal exhibits local quality differentiation where the support body provides electrical conductivity at specific contact points (through mandrel-shaped projections) while the surrounding sealing material remains electrically insulating. This localized conductivity enables electromagnetic shielding at critical interfaces without requiring the entire seal or machine elements to be conductive, thus maintaining lightweight construction while achieving shielding effectiveness.
2Reliability
If electrically conductive materials are used for electromagnetic shielding, then shielding effectiveness is improved, but weight increases
Solution Approach 1:
Instead of using electrically conductive materials throughout the entire sealing arrangement, the invention applies conductivity locally only where electrical contact is needed - specifically in the mandrel-shaped projections of the support body. The majority of the seal and the machine elements can remain lightweight plastics, achieving shielding effectiveness at minimal weight penalty.
Solution Approach 2:
The sealing arrangement uses a composite structure combining electrically conductive and electrically insulating materials in specific configurations. The support body with conductive projections interfaces with lightweight plastic machine elements, creating a hybrid system that achieves electromagnetic shielding without requiring full metallic construction, thus reducing overall weight while maintaining shielding effectiveness.
3Reliability
If mandrel-shaped projections penetrate the injection-molded skin, then electrical contact is established, but the sealing material integrity is compromised
Solution Approach 1:
The seal is segmented into a support body containing the penetrating projections and a sealing material layer that maintains the sealing function. The projections are contained within the support body structure, which is designed to accommodate their penetration through the injection-molded skin without compromising the overall seal integrity. The sealing material remains intact and functional while the projections establish electrical contact through controlled penetration points.
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 enables reliable electromagnetic shielding by establishing a conductive connection between machine elements, preventing interference waves from entering or escaping the housing, thus protecting electronic components, while reducing material consumption and weight.
Implementation Method 1
the support body comprises at least one substantially mandrel-shaped projection made of an electrically conductive material, which projection is arranged on the side of the support body facing the injection-molded skin and completely penetrates the injection-molded skin
Implementation Method 2
the seal comprises an electrically conductive support body and wherein the support body comprises at least one substantially mandrel-shaped projection made of an electrically conductive material... creating an electrically conductive connection between the metallic machine elements
Data Source
Figure 1
Figure 2
AI summary
Sealing arrangement comprising a first (1) and a second machine element (2), each made of an electrically conductive material, and a seal (3), wherein the two machine elements (1, 2) are sealed against each other by the seal (3), wherein at least one of the machine elements (1, 2) is made of an electrically conductive plastic which, due to the manufacturing process, is at least partially covered by an electrically insulating injection skin (4), wherein the seal (3) comprises an electrically conductive support body (5), wherein the support body (5) comprises at least one substantially mandrel-shaped projection (6) made of an electrically conductive material, which is arranged on the side of the support body (5) facing the injection skin (4) and completely penetrates the injection skin (4).