Urethane Cable Sheath Void Prevention via Permeable Tape
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Void formation in the sheath of urethane resin-covered cables due to moisture absorption by tape members and trapped air, which affects work efficiency and cable integrity.
Innovation Solution
A cable design featuring a non-woven fabric tape with high air permeability, made from materials like polyester, polypropylene, aramid fiber, nylon, or glass fiber, spirally wound around twisted electric wires, with the twist direction of the wires opposite to the winding direction of the tape to prevent moisture absorption and air entrapment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a tape member is used to wrap electric wires instead of coating lubricant, then the electric wires can be easily exposed from the sheath without lubricant scattering, but the tape member may absorb moisture and cause voids in the urethane resin sheath
Solution Approach 1:
The patent applies porous materials by selecting a non-woven fabric tape with high air permeability (not less than 30 cm3/cm2·sec). The porous structure allows moisture and air to pass through the tape during the molding process, preventing moisture accumulation that would cause voids in the urethane resin sheath while maintaining the tape's function as a lubricant alternative.
Solution Approach 2:
The patent applies parameter changes by specifying the air permeability parameter of the non-woven fabric tape (not less than 30 cm3/cm2·sec) and the opposite relationship between twist direction of wires and winding direction of tape. These parameter specifications ensure the tape allows sufficient moisture and air passage during molding, preventing void formation while maintaining operational ease.
2Ease of manufacture
If the sheath is molded around the tape member, then the cable structure is completed, but air including moisture remains in gaps inside the tape member and causes bubbles in the sheath
Solution Approach 1:
The patent applies porous materials by using a non-woven fabric tape with high air permeability (not less than 30 cm3/cm2·sec). This porous structure enables air and moisture trapped in gaps inside the tape to escape during the molding process, preventing bubble formation in the urethane resin sheath while maintaining structural completion.
Solution Approach 2:
The patent applies preliminary anti-action by designing the tape with high air permeability before the molding process. This preliminary structural design prevents moisture and air from being trapped during molding, proactively counteracting the potential formation of voids and bubbles in the sheath.
3Quantity of substance
If the tape member absorbs moisture from air, then the tape becomes saturated, but moisture evaporation during molding creates bubbles and voids in the sheath
Solution Approach 1:
The patent applies porous materials by using a non-woven fabric tape with high air permeability (not less than 30 cm3/cm2·sec). This porous structure allows moisture absorbed by the tape to evaporate and escape during molding, preventing bubble and void formation in the urethane resin sheath while maintaining the tape's moisture management capability.
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
Prevents void formation in the urethane resin sheath, enhancing cable reliability and work efficiency by maintaining a stable cross-sectional shape and reducing the risk of bubbles during the molding process.
Implementation Method 1
a non-woven fabric tape comprising a polyester, a polypropylene, an aramid fiber, a nylon, an acryl fiber, or a glass fiber and an air permeability defined by the Frazier method of not less than 30 cm3/cm2·sec
Data Source
AI summary
A cable includes an assembled article formed by twisting a plurality of electric wires, a tape member spirally wound around the assembled article, and a sheath covering around the tape member. The sheath includes an injection molded body including an urethane resin. The tape member includes a non-woven fabric tape including a polyester, a polypropylene, an aramid fiber, a nylon, an acryl fiber, or a glass fiber and an air permeability defined by the Frazier method of not less than 30 cm3/cm2·sec. A twist direction of the assembled article is opposite to a winding direction of the non-woven fabric tape.