Terminal-Equipped Electric Wire Waterproofing Under Negative Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In terminal-equipped electric wires, water can enter through gaps between conductive element wires due to negative pressure generated in electrical junction boxes, especially in areas with temperature fluctuations, as existing seal members are ineffective in preventing moisture absorption.
Innovation Solution
A method involving crimping terminals to both ends of an electric wire, where one end is covered with an anticorrosion member to isolate the element wire bundle from outside air and the other end has a sealing member to fill gaps between conductive element wires within a tubular insulating sheath, ensuring the sealing member remains outside the sheath and preventing water ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal member is crimped to the end portion of the electric wire to seal gaps between the terminal accommodating chamber and the electric wire, then waterproofing performance is improved, but water can still enter through gaps between conductive element wires due to negative pressure
Solution Approach 1:
The waterproofing function is divided into two separate components: a seal member that seals the gap between the terminal accommodating chamber and the electric wire, and a waterproof member that seals the gaps between conductive element wires. This segmentation allows each component to address specific water ingress paths independently, solving the problem where a single seal member cannot prevent water entry through element wire gaps under negative pressure.
Solution Approach 2:
A waterproof member (intermediary component) is introduced between the conductive element wires and the external environment. This waterproof member specifically addresses the water ingress issue through element wire gaps by filling or sealing these gaps, while the seal member handles the external sealing. The intermediary waterproof member acts as an additional barrier that prevents water from reaching the element wires even when negative pressure draws water inward.
2Object-affected harmful factors
If the sealing member is made to fill gaps between conductive element wires, then water ingress is prevented, but the flexibility of the electric wire deteriorates
Solution Approach 1:
The waterproofing treatment is applied locally only where needed - specifically at the end portion of the electric wire where water ingress is most likely to occur. The waterproof member is positioned at the terminal end to seal gaps between conductive element wires, while the rest of the electric wire maintains its original flexibility. This localized approach prevents water ingress at critical points without compromising the overall flexibility of the wire bundle.
Solution Approach 2:
Instead of making the entire electric wire rigid or fully encapsulated, the patent applies partial waterproofing action only at the end portion where terminals are crimped. The waterproof member is applied selectively to seal the critical gaps at the terminal end, providing sufficient waterproofing protection without excessive action that would compromise the flexibility of the entire electric wire assembly.
3Reliability
If terminals are crimped to both ends of the electric wire, then electrical connection is achieved, but gaps between conductive element wires create water ingress paths
Solution Approach 1:
The waterproof member is applied in advance to the end portion of the electric wire before or during the crimping process. This preliminary waterproofing action ensures that gaps between conductive element wires are sealed before water ingress can occur, while still allowing the crimping operation to achieve proper electrical connection. The waterproof member is positioned to protect the crimped portions without interfering with the electrical connectivity function.
Data Source
AI summary
A method for manufacturing a terminal-equipped electric wire includes a step of crimping a first terminal to one end of an electric wire, a step of crimping a second terminal to the other end of the electric wire with a tubular seal member, a first waterproofing step of providing, at the one end of the electric wire, an anticorrosion member that covers an element wire bundle of the electric wire, and a second waterproofing step of providing, at the other end of the electric wire, a sealing member so as to fill gaps between conductive element wires of the element wire bundle in a tubular insulating sheath. The second waterproofing step is performed after the first waterproofing step is performed.