Reactive Adhesive Wiring Harness Waterproofing
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Solution Overview
Problem
Conventional waterproofing methods for in-vehicle wiring harnesses fail to maintain 100% waterproof performance after endurance tests, such as high-temperature storage or high-humidity tests, due to adhesive force reduction and plasticizer transfer, leading to leak paths and corrosion.
Innovation Solution
A wiring harness with a waterproof structure using a reactive adhesive having a gel fraction of 20 to 70% is applied to spliced portions, where the adhesive is an ultraviolet curable crosslinked acrylic adhesive or a two-component curable crosslinked acrylic adhesive, ensuring flexible adhesion and effective sealing even in high-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is coated to seal exposed parts, then water sealing performance is improved, but adhesive flows out when pressed from outside
Solution Approach 1:
The patent controls the gel fraction parameter of the reactive adhesive within 20-70% to optimize the balance between adhesion strength and flow resistance. This parameter control prevents adhesive from flowing out when pressed from outside while maintaining effective water sealing performance at the spliced portions.
2Reliability
If waterproofing agent is filled among strands, then leak paths are blocked initially, but adhesive force decreases after endurance test
Solution Approach 1:
The patent changes from conventional low-viscosity resin to reactive adhesive with controlled gel fraction (20-70%). This parameter change ensures that the adhesive maintains strong bonding strength after endurance tests by preventing excessive plasticizer transfer from wire coating materials, thereby sustaining leak path blocking capability.
Solution Approach 2:
The patent converts the potential harm of plasticizer transfer from wire coating materials into a beneficial effect. By controlling gel fraction, the reactive adhesive resists excessive plasticizer absorption that would otherwise weaken adhesion, turning the endurance test conditions into an opportunity to demonstrate the superior stability of the adhesive system.
3Reliability
If conventional waterproofing agent is used, then initial sealing is achieved, but moisture intrusion occurs due to adhesive force reduction
Solution Approach 1:
The patent changes the waterproofing agent to reactive adhesive with controlled gel fraction (20-70%), which maintains sufficient adhesive force after endurance tests. This prevents moisture intrusion by ensuring continuous effective sealing at spliced portions, unlike conventional agents that lose adhesion strength over time.
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
The solution reliably blocks leak paths and maintains good waterproof performance over a long period by using a reactive adhesive with a suitable gel fraction, which flexibly adheres to wire diameter changes and reaction forces, preventing moisture intrusion and corrosion.
Implementation Method 1
a reactive adhesive having a gel fraction in a range of 20 to 70% is used as the waterproofing agent
Implementation Method 2
a reactive adhesive having a gel fraction in a range of 20 to 70% is used as the waterproofing agent
Implementation Method 3
the reactive adhesive is preferably an ultraviolet curable crosslinked acrylic adhesive
Data Source
AI summary
A wiring harness capable of reliably blocking a leak path after an endurance test and exhibiting a good waterproof performance over a long period of time. The wiring harness has a waterproof structure in which a spliced portion is formed by joining conductors that are exposed by partially removing coating materials, and a conductor exposed portion composed of a bundle of the exposed conductors. An outer peripheral surface of each coating material end part of each insulated wire adjacent to the conductor exposed portion are continuously covered with a waterproofing agent to seal the conductor exposed portion and is configured using a reactive adhesive having a gel fraction in a range of 20 to 70% as the waterproofing agent.