Vehicle Multi-Conductor Cable Marking Durability via Surface Roughness Control
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Solution Overview
Problem
Multi-conductor cables used in vehicle systems, such as ABS and electronic parking brakes, face issues with marking durability due to bending, contact, and exposure to mud-water and organic solvents, leading to peeling off of markings.
Innovation Solution
A multi-conductor cable design featuring core wires with twisted conductors, an insulating layer, and a sheath layer with a marking portion on the outer surface, where the arithmetic average roughness ratio of adjacent regions to the marking portion is controlled between 0.10 and 0.90, enhancing flexing resistance and marking durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a marking is formed by printing using ink on the outer peripheral surface of the cable, then the marking can be applied to provide product information, but the marking peels off due to bending, contact, and adhesion of mud-water and organic solvents
Solution Approach 1:
The patent applies local quality by creating a marking portion with different surface roughness characteristics than the peripheral region. The marking portion has an arithmetic average roughness Ra1, while the adjacent peripheral region has an arithmetic average roughness Ra2, where the ratio Ra2/Ra1 is between 0.10 and 0.90. This local differentiation in surface properties ensures that markings (whether printed or embossed) adhere better and maintain visibility despite exposure to bending, contact, and environmental contaminants.
2Adaptability or versatility
If the cable is bent in a complicated manner due to routing inside the vehicle, then the cable can be installed and function properly, but the marking on the outer peripheral surface peels off
Solution Approach 1:
The patent creates a localized marking portion with distinct surface roughness properties (Ra1) compared to the surrounding peripheral region (Ra2). The controlled ratio between Ra2 and Ra1 (0.10-0.90) ensures that the marking area maintains its integrity during cable bending and flexing, while the rest of the cable retains its flexibility for proper routing and installation.
3Loss of information
If the outer peripheral surface is smoothed or roughened to form a marking portion, then the marking identifiability is improved, but the surface uniformity is reduced
Solution Approach 1:
The patent intentionally creates local surface quality variation by forming a marking portion with arithmetic average roughness Ra1 that differs from the peripheral region's Ra2. The ratio constraint (0.10 ≤ Ra2/Ra1 ≤ 0.90) ensures that this local variation is sufficient to provide clear marking identifiability while maintaining overall surface stability and preventing excessive irregularity that could affect cable performance.
Data Source
AI summary
A multi-conductor cable for a vehicle includes core wires respectively having a conductor formed by a plurality of twisted wires, and an insulating layer covering an outer periphery of the conductor, and a sheath layer disposed around the core wires. A marking portion is partially formed on an outer peripheral surface of the sheath layer, and a ratio of an arithmetic average roughness Ra2 of a peripheral region adjacent to the marking portion, with respect to an arithmetic average roughness Ra1 of the marking portion, at the outer peripheral surface, is 0.10 or greater and 0.90 or less.