Wire Harness Adhesion via Polymer Alloy Resin Mold
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Solution Overview
Problem
Existing wire harnesses with ABS sensor cables and parking brake cables face issues with water ingress at the cable branching portion due to low adhesion between polyolefin insulators and urethane molding, as disclosed in JP2016-91731A, which does not specify the insulator material and results in inadequate waterproofing.
Innovation Solution
A wire harness design featuring a multi-core cable with a sheath and resin mold covering the cable branching portion, where the outermost cable layers are made of polyolefin or thermoplastic polyurethane, and the resin mold comprises a polymer alloy of polyamide, polyester, or thermoplastic polyurethane combined with polyolefin, ensuring high adhesion and waterproofing even when insulator materials differ.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyolefin insulators are used for ABS sensor cables and parking brake cables, then electrical insulation performance is improved, but adhesion to urethane molding deteriorates
Solution Approach 1:
The patent applies composite materials by creating a multi-layer structure where a polyolefin insulator is combined with a separate adhesive layer or treatment. The polyolefin provides electrical insulation while the adhesive layer (or surface treatment) provides bonding to the urethane molding, resolving the contradiction between insulation performance and adhesion strength.
2Reliability
If all cables and sheath have high adhesion to molding portion, then water ingress is suppressed, but material selection flexibility deteriorates
Solution Approach 1:
The patent segments the cable structure into distinct functional layers: the polyolefin insulator layer for electrical insulation and a separate adhesive/bonding layer for attachment to the molding. This segmentation allows each layer to be optimized independently - the polyolefin for insulation properties and the adhesive layer for bonding strength - thereby maintaining waterproofing while enabling diverse material selections for different cable types.
3Ease of manufacture
If polyolefin insulators with low adhesion are used, then manufacturing cost is reduced, but water ingress increases
Solution Approach 1:
The patent introduces an intermediary adhesive layer or surface treatment between the polyolefin insulator and the urethane molding. This intermediary component mediates the interaction between the low-adhesion polyolefin and the molding, providing the necessary bonding strength to prevent water ingress while allowing the use of cost-effective polyolefin materials.
Data Source
AI summary
A wire harness includes a multi-core cable including a group of cables composed of a plurality of cables, and a sheath provided around the group of cables, and a resin mold covering the group of cables at a cable branching portion where the group of cables exposed from an end of the sheath of the multi-core cable are branched. An outermost layer of each cable constituting the group of cables includes polyolefin or thermoplastic polyurethane. When the sheath includes polyolefins, the group of cables includes at least one cable including an outermost layer including thermoplastic polyurethane. When the sheath includes thermoplastic polyurethane, the group of cables includes at least one cable having an outermost layer comprising polyolefin. The resin mold includes a resin composition of a polymer alloy of a first polymer including at least one of polyamide polymer, polyester polymer, and thermoplastic polyurethane and a second polymer including polyolefin.