Wire Harness Waterproof Structure to Prevent Rubber Stopper Wear
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Solution Overview
Problem
Existing cable waterproof structures, such as those described in Patent Literature 1 and Patent Literature 2, suffer from wear of the rubber stopper due to slip between the sheath and the rubber stopper when the cable is bent, leading to a decrease in sealing ability over time.
Innovation Solution
A wire harness and cable waterproof structure that includes a rubber stopper with integral sheath and wire sealing portions, and a cover made of a harder material that crimps and holds both the sheath and the rubber stopper, preventing slip and wear during bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber stopper is used to seal the sheath end, then sealing ability is improved, but wear occurs due to slip between sheath and rubber stopper during bending, reducing sealing property over time
Solution Approach 1:
The patent combines the rubber stopper and cap into a single integrated unit where the cap is molded directly onto the rubber stopper. This merging eliminates the relative movement and wear that would occur between separate components, while maintaining the sealing function against water ingress at the sheath end.
Solution Approach 2:
The rubber stopper is designed as a flexible element that can deform to seal around the sheath end, while the hard cap provides structural support. This combination allows the sealing surface to conform to the sheath while preventing the wear issues that would occur with rigid sealing mechanisms.
2Stability of the object's composition
If the cap engages with the holding portion to suppress relative movement, then sealing stability is improved, but tilt during bending causes slight slip and wear accumulation
Solution Approach 1:
By merging the cap and rubber stopper into one integral component, the patent eliminates the engagement interface between separate parts. This removes the source of tilt-induced slip while maintaining stable positioning through the integrated structure's direct attachment to the sheath.
3Strength
If a harder cover material is used to accommodate the rubber stopper, then structural strength is improved, but complexity of the sealing structure increases
Solution Approach 1:
The patent merges multiple functions into the single cap structure: it provides structural strength as a hard cover, integrates the sealing function through direct contact with the sheath, and eliminates the need for separate engagement mechanisms. This reduces overall structural complexity while maintaining necessary strength.
Solution Approach 2:
The cap is designed to perform multiple functions simultaneously: it protects the rubber stopper, provides structural strength, creates the sealing interface with the sheath, and prevents water ingress. This multi-functionality reduces the number of separate components needed in the sealing structure.
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 proposed solution effectively reduces wear on the rubber stopper and maintains the sealing property for a long period by preventing slip between the sheath and the rubber stopper, even when the cable is repeatedly bent.
Implementation Method 1
a crimping portion that crimps and holds the sheath and the rubber stopper
Implementation Method 2
a sheath sealing portion that comes into contact with an outer peripheral surface of the sheath
Data Source
AI summary
A wire harness is provided with a cable including wires coated with a sheath, a rubber stopper that covers an end of the sheath together with a portion in a longitudinal direction of the wires, and a cover made of a harder material than the rubber stopper and accommodating the rubber stopper. The rubber stopper integrally has a sheath sealing portion having an inner peripheral surface that comes into contact with an outer peripheral surface of the sheath, and a wire sealing portion including plural insertion holes to which the wires are inserted. The cover integrally has a sheath holding portion that crimps and holds an uncovered portion of the sheath that is not covered by the rubber stopper, and a rubber stopper holding portion that crimps and holds the rubber stopper.