Liquid-Proof Wire Harness Seal Using Enamel Coating
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Solution Overview
Problem
Conventional wire harnesses face increased complexity, cost, and size issues due to the need for multiple seal members to prevent liquid infiltration at the terminal parts, which complicates the waterproofing process.
Innovation Solution
A wire harness with a single core conductor coated in an enamel insulation film, eliminating gaps between the insulation layer and conductor, and using integral seal members to securely seal the connection points, thereby simplifying the configuration and reducing the number of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple seal members are used to prevent liquid infiltration at terminal parts, then waterproofing reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple sealing functions into a single integrated seal member structure. The seal member includes an outer lip that contacts the insulation cover and an inner lip that contacts the conductor, merging what would traditionally require separate seal members into one unified component. This reduces structural complexity while maintaining waterproofing reliability through integrated dual-contact sealing.
Solution Approach 2:
The seal member is designed to perform multiple sealing functions simultaneously: the outer lip seals the gap between the insulation cover and the terminal housing, while the inner lip seals the gap between the conductor and the terminal housing. This multi-functional design eliminates the need for separate seal members for different sealing locations, reducing overall device complexity.
2Reliability
If multiple seal members are used to prevent liquid infiltration, then waterproofing reliability is improved, but manufacturing cost increases
Solution Approach 1:
By integrating multiple sealing functions into a single seal member, the patent reduces the total number of components that need to be manufactured, stored, and assembled. This consolidation lowers manufacturing costs while maintaining the waterproofing reliability achieved through the combined outer lip and inner lip sealing actions.
3Reliability
If multiple seal members are used to prevent liquid infiltration, then waterproofing reliability is improved, but connector size increases
Solution Approach 1:
The patent merges multiple seal members into one integrated component, which reduces the overall volume required for the connector assembly. The single seal member with its dual-lip structure occupies less space than multiple separate seal members would require, thereby reducing connector size while maintaining waterproofing reliability.
4Ease of manufacture
If twisted wire with resin insulation cover is used, then ease of manufacture is improved, but gaps between conductor and insulation layer create liquid infiltration paths
Solution Approach 1:
The patent extracts and eliminates the harmful gaps between the conductor and insulation layer by using a solid rod conductor design. This removes the infiltration path that would otherwise exist in twisted wire constructions, preventing liquid from entering along the conductor-insulation interface while maintaining manufacturing feasibility.
Data Source
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AI summary
There is provided a liquid-proof structure for a wire harness having a simple configuration and capable of suppressing the cost and reducing a size of a liquid-proof connector part. An outer periphery of a single core conductor (2) having a round rod shape and configuring an electric wire (1) is coated with an insulation film (4) such as enamel, except for a partial conductor exposed part (3) at an end portion of the single core conductor (2), an end portion of the single core conductor is inserted into a through-hole (7) of a seal member (6) made of an elastic material that is mounted to a waterproof casing with being closely contacted thereto, an inner periphery of the through-hole of the seal member is in close contact with an outer periphery of the coated insulation film (4), and a connection terminal (5) is provided to the partial conductor exposed part at the end portion of the single core conductor.