Waterproof Wire Harness with Internal Gas Flow Paths
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Solution Overview
Problem
In wire harnesses, the resin material used to waterproof exposed conductor portions can trap air inside the coating materials, leading to pressure buildup when exposed to high temperatures, which can cause the rubber stopper of the waterproofing terminal to loosen due to expanding air having no escape route.
Innovation Solution
A wire harness design featuring a film-like or tubular protective material covering the exposed conductor portion and its adjacent coating material end portions, with a waterproofing agent sealing the gaps between the protective material and the coating material, and incorporating gas flow paths within the conductor strands to allow air to escape from the coating material to the exposed conductor portion, preventing pressure buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resin material is allowed to fully penetrate into the gaps between the strands constituting the conductors to enhance waterproofing effect, then waterproofing performance is improved, but air inside the coating materials becomes cut off from escaping, causing pressure buildup when exposed to high temperature
Solution Approach 1:
The patent applies different properties to different regions of the conductor structure. The gaps between strands are selectively treated: some gaps are filled with resin material for waterproofing, while flow paths are maintained in other gaps to allow air escape. This local differentiation resolves the contradiction by ensuring waterproofing where needed while preventing pressure buildup through strategic air escape routes.
Solution Approach 2:
The patent introduces flow paths as intermediary channels within the conductor structure. These flow paths act as mediators between the trapped air and the external environment, allowing air to escape gradually without compromising the overall waterproofing structure. The flow paths serve as a buffer that prevents direct pressure transmission to the rubber stopper while maintaining waterproof integrity.
2Reliability
If gaps between strands are filled with resin material to prevent water intrusion, then waterproofing is enhanced, but the complexity of the waterproofing structure increases due to multiple sealing requirements
Solution Approach 1:
The resin material serves multiple functions simultaneously: it provides waterproofing by filling gaps between strands, maintains structural integrity of the conductor bundle, and when configured with flow paths, enables air escape. This multi-functionality reduces the need for separate components and simplifies the overall waterproofing structure while maintaining high reliability.
Solution Approach 2:
The patent implements a nested structure where flow paths are integrated within the resin-filled gap structure. The flow paths are embedded within the conductor bundle and surrounded by resin material, creating a hierarchical arrangement where the resin provides external waterproofing while internal flow paths handle air management. This nesting eliminates the need for separate air escape components.
3Reliability
If the exposed conductor portion is covered with protective material and sealed with waterproofing agent, then waterproofing is improved, but air escape paths may be blocked, leading to pressure buildup at the terminal
Solution Approach 1:
The patent incorporates flow paths during the manufacturing process, before the waterproofing agent is applied and before the protective material is installed. This preliminary action ensures that air escape routes are established in advance, allowing air to escape through the flow paths rather than being trapped and pressurizing the terminal. The flow paths are created as integral part of the conductor structure before final waterproofing sealing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures reliable waterproofing by preventing water intrusion and allowing air to escape, thus preventing the loosening of the rubber stopper due to pressure from expanded air, even when insulated wires are exposed to high temperatures.
Implementation Method 1
a gap between a coating material and the protective material covering the coating material is sealed with a waterproofing agent
Implementation Method 2
at least one insulated wire of the plurality of insulated wires has a flow path through which gas flows, the flow path being created in gaps between strands that constitute the conductor of the insulated wire
Implementation Method 3
If at least one of the insulated wires included in such a wire harness is exposed to a high temperature, the air inside the coating material expands
Data Source
AI summary
A wire harness can ensure waterproofness of an exposed conductor portion, and even when at least one of insulated wires is exposed to a high temperature, can suppress loosening of a rubber stopper of a waterproofing terminal. An outer periphery of a region containing an exposed conductor portion and coating material end portions is continuously covered with a protective film. At each of the coating material end portions, a gap between a coating material and the protective film covering the coating material is sealed with a waterproofing agent. At least one insulated wire has a flow path through which gas flows, the flow path being created in gaps between strands that constitute a conductor of the insulated wire and reaching from a coating material end portion opposite to the coating material end portion adjacent to the exposed conductor portion to a splice portion.