Composite Cable With Irregular Inner Sheath For Flex Durability
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Solution Overview
Problem
The existing composite cables used in vehicles for connecting wheel-side and vehicle-body side components face issues with flex durability due to high adhesion between the urethane-based resin inner sheath and power lines, leading to reduced relative movement, and low adhesion with molded resins, which can result in water ingress and connector/sensor failures.
Innovation Solution
A composite harness design featuring a multicore wire with an irregularly formed urethane-based resin inner sheath for improved adhesion with power lines and molded resins, combined with a tape member and jacket to enhance flex durability and prevent water ingress, while maintaining ease of termination and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth inner sheath is used, then the composite cable is easy to manufacture, but the adhesion between the inner sheath and molded resin is insufficient, allowing water ingress
Solution Approach 1:
The invention changes the surface parameters of the inner sheath by forming irregularities (protrusions and recesses) on its outer surface. This parameter change increases the surface area and creates mechanical interlocking with the molded resin, thereby improving adhesion without complicating the manufacturing process. The irregularities can be formed during extrusion or by subsequent processing, maintaining manufacturing efficiency while achieving reliable water ingress prevention.
2Stability of the object's composition
If high adhesion between inner sheath and power lines is used, then the cable structure is stable, but flex durability decreases due to restricted relative movement
Solution Approach 1:
The invention applies local quality by creating irregularities only at specific locations on the inner sheath surface, particularly at the interface with molded resin portions. This localized surface modification provides strong adhesion where needed (at connector and sensor portions) while maintaining smoother surfaces in other areas that allow relative movement between the inner sheath and power lines during flexing, thus preserving flex durability while ensuring structural stability at critical points.
Data Source
AI summary
A composite harness includes a composite cable that includes a plurality of first electric wires, a multicore wire formed by covering a plurality of second electric wires having a smaller diameter than the plurality of first electric wires with one urethane-based resin inner sheath to be in contact with the first electric wires, and a jacket covering an outer periphery of the plurality of first electric wires and the multicore wire, and a molded resin provided at an end portion of the composite cable so as to cover an outer surface of the inner sheath at an end portion of the multicore wire. The outer surface of the inner sheath is irregularity-formed at least at a portion in contact with the plurality of first electric wires and a portion covered with the molded resin.