Shield Connector Insulation Layer Prevents Galvanic Corrosion
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Solution Overview
Problem
In shielded connectors for hybrid electric vehicles, the bimetallic contact between copper or copper alloy braided conductors and stainless steel shield rings can lead to galvanic corrosion, reducing the shielding effect.
Innovation Solution
A shielded connector design that includes an insulation layer, specifically an acetate tape made of semisynthetic fibers from acetylcellulose, between the braided conductor and the shield ring to prevent direct contact and thus galvanic corrosion, ensuring continuous excellent shielding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a shield ring made of stainless steel is used to clamp the braided conductor to the shield shell, then the mechanical strength and clamping force are improved, but galvanic corrosion occurs due to bimetallic contact between the stainless steel shield ring and copper braided conductor, reducing the shielding effect
Solution Approach 1:
An insulation layer is introduced as an intermediary between the stainless steel shield ring and copper braided conductor. This insulation layer prevents direct contact between the dissimilar metals, eliminating the galvanic corrosion pathway while allowing the shield ring to maintain its clamping function on the braided conductor assembly.
Solution Approach 2:
The contact interface between the shield ring and braided conductor is segmented into multiple layers: the outer shield ring, the insulation layer, and the braided conductor. This segmentation separates the mechanical clamping function from the electrical contact, allowing each layer to perform its specific function without causing galvanic corrosion.
2Reliability
If the shield ring is directly swaged to the braided conductor without insulation, then the electrical conductivity and shielding effect are improved, but galvanic corrosion occurs between different metal materials, reducing long-term performance
Solution Approach 1:
The insulation layer serves as a protective intermediary that prevents the galvanic reaction between dissimilar metals. It allows the shielding circuit to function effectively while protecting the braided conductor and shield ring from corrosion, thereby extending the service life of the connector.
Solution Approach 2:
The insulation layer is applied in advance to the braided conductor before the shield ring is swaged onto it. This preliminary protective measure prevents galvanic corrosion from occurring during the assembly process and throughout the service life of the connector, ensuring long-term reliability.
3Reliability
If an insulation layer is added between the braided conductor and shield ring, then galvanic corrosion is prevented, but the device complexity and manufacturing steps increase
Solution Approach 1:
A thin film insulation layer is applied to the braided conductor before the shield ring is swaged onto it. This thin film provides sufficient electrical insulation to prevent galvanic corrosion while adding minimal complexity to the overall structure. The insulation layer can be applied as a wrap or coating that integrates smoothly with the existing components.
Solution Approach 2:
The insulation layer application is combined with the existing swaging process. The insulation layer is applied to the braided conductor, and then the shield ring is swaged onto the insulated conductor in the same assembly operation, merging two functions (insulation and clamping) into a single integrated manufacturing step.
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 insulation layer effectively prevents galvanic corrosion, maintaining an excellent shielding effect and high performance over a long period by insulating the braided conductor and shield ring from each other, even when made of different metals.
Implementation Method 1
an insulation layer is provided between the braided conductor and the shield ring... the braided conductor and the shield ring are insulated from each other by the insulation layer
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The male shielded connector (12) of the invention includes terminals which are connected to end portions of electric wires (23), a housing (21) which contains the terminals, a shield shell (22) which covers the housing (21), a braided conductor (24) which is externally provided to the wire (23) and is covered on the shield shell (22), and a shield ring (25) which is swaged to the outer circumference of the braided conductor (24) to fix the braided conductor in a state that the braided conductor (24) is electrically connected to the shield shell (22), the shield ring being made of a metal material. An insulation layer (51) is provided between the braided conductor (24) and the shield ring (25).