Wire Harness Waterproofing via Integrated Soft Resin Sealing
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Solution Overview
Problem
Conventional wire harnesses face productivity and reliability issues due to the use of different metals for core wires and terminal fixtures, leading to corrosion and inefficiencies in manufacturing, particularly with the need for multiple applications of waterproof sealant and potential gaps that allow water infiltration.
Innovation Solution
A wire harness design featuring a core wire covered by a synthetic resin covering part, with a terminal fixture attached and a ring-shaped waterproof member made of soft resin between the housing and covering part, eliminating the need for conventional waterproof sealants and simplifying the manufacturing process by integrating the waterproof member with the covering part through injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a core wire made of aluminum and a terminal fixture made of copper or copper alloy are used, then weight reduction is achieved, but electric corrosion occurs due to local cell formation at the contact portion
Solution Approach 1:
A transition piece made of aluminum alloy is introduced as an intermediary component between the aluminum core wire and the copper terminal fixture. This transition piece has a first connection portion that connects to the aluminum core wire and a second connection portion that connects to the copper terminal fixture, thereby preventing direct contact between dissimilar metals and eliminating local cell formation while maintaining the weight reduction benefits of using aluminum core wire.
2Reliability
If waterproof sealant is applied multiple times in the manufacturing process, then waterproof performance is improved, but manufacturing time is prolonged and productivity is reduced
Solution Approach 1:
The transition piece is designed with an integrated waterproof structure where the second connection portion is formed with a waterproof seal built-in. This integration combines the electrical connection function and the waterproof sealing function into a single component, eliminating the need for separate waterproof sealant application steps and achieving both reliable waterproofing and improved manufacturing efficiency.
3Reliability
If the middle of the pipe member and core wire are swaged together to form connection, then electrical connection is achieved, but the terminal fixture manufacturing time is prolonged due to multiple processes
Solution Approach 1:
The transition piece is pre-formed with a specific structure where the first connection portion is designed to connect to the core wire and the second connection portion is designed to connect to the terminal fixture. This preliminary structuring allows for streamlined assembly processes and reduces the number of steps required to achieve reliable electrical connections.
4Ease of manufacture
If gap between terminal fixture and covering part is not filled with waterproof sealant, then manufacturing process is simplified, but water infiltration occurs and reliability is compromised
Solution Approach 1:
The waterproof structure is integrated into the transition piece itself, where the second connection portion includes built-in waterproof sealing features. This eliminates the need for separate waterproof sealant application to fill gaps between the terminal fixture and covering part, achieving both manufacturing simplicity and reliable waterproofing simultaneously.
Data Source
AI summary
The present invention is to provide a wire harness capable of improving productivity and reducing cost as well as enhancing waterproof performance to secure reliability, and a method for manufacturing the wire harness, The wire harness includes an electronic wire having a core wire and a covering part covering the core wire, a male terminal attached to the core wire exposed out of the covering part of the electric wire, a housing attached to the covering part and formed to lay the male terminal therein, and a ring-shaped waterproof member disposed between the housing and the covering part, filling a gap therebetween, and made of soft resin.