Composite Shielded Wire Grounding Without a Drain Line
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Solution Overview
Problem
In shielded electrical wires with film-like metallic shields, the use of a drain line for grounding increases manufacturing costs and wire diameter, while direct terminal attachment risks damaging the metallic shield due to its low strength.
Innovation Solution
A composite electrical wire design that includes a lead wire electrically connected to the metallic shield and fixed using a fixing member, eliminating the need for a drain line and ensuring the metallic shield's strength against external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drain line is arranged inside the metallic shield for grounding, then the metallic shield can be grounded, but the manufacturing cost increases and the outer diameter becomes larger
Solution Approach 1:
The invention extracts the grounding function from the internal structure (drain line inside shield) and relocates it to the external structure (lead wire attached to shield outer surface). This eliminates the need for a drain line while maintaining grounding capability, thereby reducing structural complexity and outer diameter without sacrificing reliability
Solution Approach 2:
The invention transitions the grounding connection from a radial arrangement (drain line inside the shield cross-section) to an axial arrangement (lead wire attached to the outer surface extending along the shield). This dimensional change eliminates the space requirement for a drain line within the shield structure, reducing both complexity and diameter
2Device complexity
If no drain line is provided and terminal is directly attached to metallic shield, then manufacturing cost and diameter are reduced, but the metallic shield is prone to damage such as rupture or tearing
Solution Approach 1:
The invention introduces a lead wire as an intermediary element between the terminal and the metallic shield. Instead of directly attaching the terminal to the shield (which causes damage), the lead wire serves as a mediator that absorbs mechanical stress and protects the shield from rupture or tearing while maintaining electrical connection
Solution Approach 2:
The lead wire acts as a cushioning element that预先 absorbs and distributes mechanical forces before they can reach the metallic shield. This beforehand cushioning prevents the shield from suffering damage under external forces such as vibration or installation stress
3Device complexity
If a lead wire is used for grounding without drain line, then cost and diameter are reduced, but the metallic shield still needs to maintain strength against external forces
Solution Approach 1:
The lead wire serves as a protective intermediary that decouples the mechanical stress from the metallic shield while maintaining electrical connection. This allows the shield to maintain its strength against external forces without the need for a reinforcing drain line
Solution Approach 2:
The invention segments the grounding function into two separate components: the lead wire for electrical connection and the metallic shield for electromagnetic protection. This segmentation allows each component to optimize its function without compromising the other, maintaining shield strength while achieving structural simplicity
Data Source
AI summary
A composite electrical wire 1 includes a shielded electrical wire 10 that includes one or more insulated electrical wires 11 and a film-like metallic shield that covers the outer periphery of the one or more insulated electrical wires 11, a lead wire 20, and a fixing member 30 that fixes the lead wire 20 to the shielded electrical wire 10. The metallic shield includes a covering part 14a that covers the outer periphery of the shielded electrical wire 10. The lead wire 20 overlaps with the covering part 14a and is electrically connected to the metallic shield. The fixing member 30 presses the mutually-overlapping covering part 14a and lead wire 20 radially inward with respect to the shielded electrical wire 10, and fixes the covering part 14a and the lead wire 20 to the shielded electrical wire 10.