Flat Cable Waterproofing via Segmented Sheath Rigidity
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Solution Overview
Problem
Conventional waterproofing methods for flat cables, such as using potting or molding resins, are labor-intensive and prone to performance variations, and attaching a rubber stopper to flat cables results in uneven surface pressure, allowing water ingress due to the low rigidity of the flat sheath.
Innovation Solution
A flat cable design with a sheath that includes paired ends, a coupler, and integral reinforcement, which prevents inward deformation when a rubber stopper is attached, ensuring consistent and high surface pressure across the sheath, and a rubber stopper with a sheath-covering and wire-covering to prevent water entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber stopper is attached to the terminal end portion of a flat cable, then waterproofing is achieved, but the surface pressure becomes uneven and water ingress occurs due to low sheath rigidity
Solution Approach 1:
The sheath is segmented into a flat portion and a cylindrical portion with different cross-sectional shapes. The cylindrical portion provides the necessary rigidity to withstand the pressing force of the rubber stopper, while the flat portion maintains flexibility for the cable's main body. This segmentation allows the sheath to simultaneously achieve waterproofing reliability and mechanical strength.
Solution Approach 2:
The sheath is designed with local quality variations: the cylindrical portion at the terminal end has high rigidity to resist deformation under the rubber stopper's pressing force, ensuring uniform surface pressure and effective waterproofing. The flat portion in the cable body maintains flexibility. This localized structural optimization resolves the contradiction between overall flexibility and local strength requirements.
2Reliability
If conventional waterproofing methods (potting or molding resin) are used, then waterproofing is achieved, but the number of processing steps and man-hours increase
Solution Approach 1:
The invention extracts and eliminates the need for separate waterproofing processing steps by integrating the waterproofing function directly into the sheath structure. The cylindrical portion's geometry enables direct attachment of the rubber stopper without requiring potting resin or molding resin applications, thereby removing unnecessary processing steps and improving productivity while maintaining waterproofing reliability.
Solution Approach 2:
The cylindrical portion of the sheath serves multiple functions: it provides structural rigidity, enables direct rubber stopper attachment, and ensures waterproofing performance. This multi-functionality eliminates the need for separate waterproofing treatments, reducing processing complexity and increasing production efficiency.
3Device complexity
If a rubber stopper is attached to a flat cable without reinforcement, then the structure remains simple, but water or foreign objects easily enter between the rubber stopper and sheath
Solution Approach 1:
The sheath is divided into distinct flat and cylindrical portions, with the cylindrical portion specifically designed at the terminal end to provide the necessary geometric form for rubber stopper attachment. This segmentation achieves reliable waterproofing without requiring additional reinforcement structures or complex design modifications.
Data Source
AI summary
A flat cable that includes a plurality of cores each including one insulated wire and/or a plurality of insulated wires that are twisted together, the cores being lined up in a cable width direction, which is orthogonal to a longitudinal direction of the insulated wires; a sheath that collectively covers the plurality of cores; and a space that is surrounded by an outer surface of one of the plurality of cores, an outer surface of another one of the plurality of cores that is adjacent to the one of the plurality of cores, and an inner surface of the sheath.