Catheter Wire Core Bundle with Opposite Winding Tape
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Solution Overview
Problem
Conventional catheter wires face issues with unstable electrical characteristics, difficulty in reducing diameter for intravascular use, and deterioration of straight-advancing properties when bent, particularly when equipped with ultrasonic transducers.
Innovation Solution
A catheter wire design featuring a core bundle of twisted solid conductors with a fluorine resin insulation, a spirally wound binding tape layer, a metal shield layer, and a sheath layer, where the binding tape is wound opposite to the core wire twisting direction, and the metal wire has a high tensile strength and conductivity, optimizing the P/PD ratio and using silver-plated wires for improved elasticity and electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diameter of the catheter wire is reduced to not more than 0.3 mm for intravascular use, then the wire can be effectively used in blood vessels, but the electrical characteristics deteriorate due to increased conductor resistance
Solution Approach 1:
The patent uses a composite structure with a core bundle of multiple insulated conductors twisted together, surrounded by a metal shield layer and fluorine resin sheath. This composite design allows the wire to maintain a small outer diameter (0.2-0.3 mm) while the internal multiple conductors provide sufficient cross-sectional area for low resistance and stable electrical characteristics.
2Ease of manufacture
If the coating layer is dissolved and removed using chemical for connecting ultrasonic transducer, then the transducer can be connected, but the processability and workability deteriorate
Solution Approach 1:
The patent employs a fluorine resin coating layer that is designed to be easily removed by simple mechanical means such as sanding or filing, rather than requiring complex chemical dissolution processes. This makes the terminal processing more straightforward and improves workability while still allowing effective ultrasonic transducer connection.
3Device complexity
If the signal wire and ground wire are separated when the twisted wire is bent, then the structure is simple, but the electrical characteristics become unstable
Solution Approach 1:
The patent combines the signal conductors and ground conductor into a single core bundle where multiple insulated conductors are twisted together. This merged structure ensures that signal and ground wires remain in close proximity and maintain stable electrical characteristics even when the wire is bent, while still keeping the overall structure relatively simple.
Solution Approach 2:
The patent uses a fluorine resin coating layer as a flexible protective shell that encapsulates the core bundle. This thin film layer maintains the structural integrity and electrical stability of the wire during bending, preventing separation between signal and ground wires while allowing the wire to flex appropriately.
4Strength
If the coaxial cable is made thick (0.2 mm) to ensure structural integrity, then the cable is mechanically strong, but the overall outer diameter cannot be reduced to not more than 0.3 mm
Solution Approach 1:
The patent divides the conductor structure into multiple separate insulated conductors (core bundle) that are twisted together, rather than using a single thick coaxial cable. This segmentation allows the total cross-sectional area to be maintained for mechanical strength while arranging the conductors in a compact configuration that minimizes the overall outer diameter to 0.2-0.3 mm.
Solution Approach 2:
The patent nests the insulated conductors within a compact core bundle structure, surrounded by a metal shield layer and fluorine resin sheath. This nested arrangement maximizes the use of internal space, allowing sufficient conductor area for mechanical strength while keeping the external diameter small for intravascular application.
Data Source
AI summary
A catheter wire includes a core bundle formed by twisting a plurality of core wires each including a solid conductor covered with an insulation, a tape layer formed by spirally winding a binding tape on an outer periphery of the core bundle, a shield layer formed by spirally winding a metal wire on an outer periphery of the tape layer, and a sheath layer formed on an outer periphery of the shield layer. The binding tape is wound in a direction opposite to a twisting direction of the core wires. The solid conductor and the metal wire have a tensile strength of not less than 900 MPa and an elongation percentage of not more than 2%.