Wire Harness Waterproofing via Segmented Rubber Caps
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Solution Overview
Problem
Conventional wire harnesses with integrated sensor and parking brake electric wires suffer from inadequate waterproofing due to insufficient transmission of tightening force, leading to moisture ingress through holes in the rubber cap, especially when wires are bent adjacent to open ends.
Innovation Solution
A wire harness design featuring a sheath with insulated electric wires and a molded rubber-like elastic member over the end portion, with cylindrical guiding out portions for each wire type, tightened by separate members to enhance waterproofing and accommodate different branching directions of the wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single rubber cap with through holes is used for multiple electric wires, then the structure is simplified, but the waterproofing property deteriorates because tightening force is not sufficiently transmitted to all wires
Solution Approach 1:
The rubber cap is divided into multiple independent cap portions, each corresponding to a specific electric wire. Each cap portion has its own through hole and is independently tightenable, ensuring that tightening force is effectively transmitted to each wire individually while maintaining overall structural organization.
Solution Approach 2:
Each cap portion is designed with specific local characteristics tailored to its corresponding wire, including customized through hole positions, shapes, and tightening mechanisms. This allows each region of the rubber cap to optimize its waterproofing and wire retention properties independently.
2Adaptability or versatility
If electric wires are allowed to branch freely from the sheath, then the connection destinations can be accommodated, but moisture ingress occurs through through holes when wires are bent adjacent to open ends
Solution Approach 1:
The rubber cap portions are pre-installed on the electric wires before the wires are routed to their connection destinations. This preliminary action ensures that the wires are already protected and secured at the sheath end, preventing moisture ingress before the wires undergo any bending or routing.
Solution Approach 2:
The rubber cap portions act as intermediary protective elements between the sheath and the external environment. They provide a sealed interface that prevents moisture from penetrating along the wires, while still allowing the wires to be guided to their respective connection destinations through the cap portions.
3Device complexity
If a single tightening ring is used for the rubber cap, then the attachment is simplified, but the tightening force is not sufficiently transmitted to all electric wires
Solution Approach 1:
The single tightening ring is replaced with multiple independent tightening rings, each corresponding to a specific cap portion and electric wire. This segmentation allows each wire to receive adequate tightening force independently, ensuring reliable waterproofing and wire retention for each connection point.
Solution Approach 2:
Each tightening ring is positioned and sized to apply optimal tightening force locally to its corresponding cap portion and wire. This localized tightening approach ensures that each wire receives the necessary clamping force without requiring excessive force from a single centralized tightening mechanism.
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 design significantly improves waterproofing by ensuring consistent tightening and independent guidance of wires, reducing moisture ingress and protecting the wires from damage due to vehicle vibrations.
Implementation Method 1
a molded member (5) made of a rubber-like elastic body
Data Source
AI summary
A wire harness is composed of a plurality of insulated electric wires, each including a conductor wire, and an insulating member provided over the conductor wire, a sheath provided over a part in a longitudinal direction of the plurality of insulated electric wires, and a molded member comprising a rubber-like elastic body, and provided over an end portion of the sheath with the plurality of insulated electric wires being guided out therefrom, and respective one parts of the plurality of insulated electric wires being guided out from the end portion of the sheath. The molded member includes a plurality of cylindrical shape guiding out portions, which are configured to guide out the respective one parts of the plurality of insulated electric wires respectively, wherein outer peripheral surfaces of the plurality of guiding out portions are tightened by tightening members respectively.