Plug Connector Shielding Ring for Low Contact Resistance
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Solution Overview
Problem
Electrical plug connectors face issues with high contact resistance due to aluminum oxide formation and contact corrosion, especially in humid environments, which can lead to increased resistance over time, particularly in single-wire shielding applications.
Innovation Solution
A plug connector system design featuring a housing with a ring and sheet-metal shield configuration, where the ring is pressed into the housing to create a large, low-resistance contact area, and the use of materials like copper and stainless steel to minimize corrosion, along with surface coatings to reduce contact resistance and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If aluminum is used for the housing material, then thermal conductivity and shielding capability are improved, but electrical contact resistance increases due to aluminum oxide formation
Solution Approach 1:
A ring made of electrically conductive material (such as copper or copper alloy) is introduced as an intermediary element between the aluminum housing and the sheet-metal shield. This ring serves as a mediator that provides excellent electrical conductivity and low contact resistance, compensating for the poor electrical conductivity of aluminum oxide that forms on the aluminum housing surface.
Solution Approach 2:
The solution employs a composite structure combining aluminum housing (for thermal conductivity and shielding) with a copper or copper alloy ring (for electrical conductivity). This composite approach allows the system to benefit from both materials' advantages: aluminum's thermal properties and copper's electrical properties.
2Reliability
If copper is used for the shielding element, then electrical conductivity is improved, but contact corrosion occurs at the aluminum-copper interface in humid environments
Solution Approach 1:
The ring acts as a protective intermediary between aluminum and copper materials, preventing direct contact between these two dissimilar metals. By introducing this intermediate layer, galvanic corrosion is prevented while maintaining excellent electrical conductivity through the copper-containing ring structure.
3Ease of manufacture
If aluminum housing is used, then manufacturing cost is reduced, but creep occurs under large pressure affecting contact stability
Solution Approach 1:
The ring serves as a mechanically stable intermediary that transfers and distributes contact forces. It protects the aluminum housing from excessive point loads that would cause creep, while maintaining stable electrical contact through its own structural integrity and elastic properties.
4Device complexity
If direct contact between housing and shielding element is made, then device complexity is reduced, but contact resistance increases over time due to oxidation and corrosion
Solution Approach 1:
The ring is a simple annular component that provides a reliable electrical connection interface. While it adds one element to the structure, its simple geometry and function maintain ease of manufacturing and assembly, while dramatically improving long-term contact reliability by preventing direct aluminum-copper contact and oxidation.
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 design achieves a stable, low contact resistance over the service life of the plug connector system, preventing corrosion and ensuring reliable shielding with reduced manufacturing complexity and costs.
Implementation Method 1
The ring is pressed into the housing to create a large, low-resistance contact area
Implementation Method 2
large shielding currents can occur
Implementation Method 3
Aluminum can, however, generally form, on its surface, aluminum oxide that does not have particularly good electrical conductivity
Implementation Method 4
because of the differing electrochemical standard electrode potentials of aluminum and copper, so-called 'contact corrosion' can occur
Data Source
AI summary
A plug connector system is described. The plug connector system includes: a plug connector; a housing on which the plug connector is installed; the housing having an opening having a first inner wall; the plug connector having a sheet-metal shield that projects at least in portions into the opening; a ring being disposed in the opening and, with an outer wall, electrically contacting the first inner wall of the opening; the sheet-metal shield electrically contacting, with a further outer wall of the sheet-metal shield, a second inner wall of the ring.