Sensor Harness Cable Sheath Roughness for Stronger Resin Sealing
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Solution Overview
Problem
Existing electrically insulated cables used in automotive sensors face challenges in achieving enhanced waterproofing and adhesion with resin sealing, particularly when exposed to water or ice, due to insufficient adhesion between the cable and the resin.
Innovation Solution
The electrically insulated cable features a sheath with an average surface roughness of 15 μm to 75 μm, which increases the contact area with resin, enhancing adhesion and waterproofing, while maintaining dimensional accuracy and abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the outer surface of the sheath is made smooth to enhance appearance, then the appearance quality is improved, but the adhesion with resin sealing is reduced
Solution Approach 1:
The patent applies different surface quality requirements to different functional zones: the outer surface maintains sufficient smoothness for appearance (Rz ≤ 75 μm), while the inner surface is designed with high roughness (Rz ≥ 15 μm) to maximize adhesion with resin sealing. This local differentiation resolves the contradiction between appearance quality and bonding strength.
2Strength
If the surface roughness Rz is increased to enhance adhesion with resin sealing, then the adhesion strength is improved, but the dimensional accuracy may deteriorate
Solution Approach 1:
The patent differentiates surface roughness requirements between inner and outer surfaces: the inner surface (contacting resin) has Rz ≥ 15 μm for maximum adhesion, while the outer surface maintains Rz ≤ 75 μm for dimensional accuracy and appearance. This localized quality control allows high roughness where needed without compromising overall manufacturing precision.
3Reliability
If the surface roughness Rz is increased to enhance adhesion with resin sealing, then the waterproofing performance is improved, but the abrasion resistance may deteriorate
Solution Approach 1:
The patent applies different surface roughness characteristics to different surfaces: the inner surface has high roughness (Rz ≥ 15 μm) to enhance waterproofing through improved resin adhesion, while the outer surface maintains moderate smoothness (Rz ≤ 75 μm) to preserve abrasion resistance. This spatial differentiation resolves the contradiction between waterproofing and wear resistance.
Data Source
AI summary
An electrically insulated cable that is excellent in in adhesion with a resin used for resin sealing is provided. According to the present invention, an electrically insulated cable (10) includes: a plurality of coated electric wires (11) and a sheath (12) covering outer peripheries of the plurality of coated electric wires, wherein an average value of surface roughness Rz of an outer surface of the sheath is 15 μm or more and 75 μm or less.