Medical Guide Wire Tapered Core Rotation Transmission
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Solution Overview
Problem
Existing medical guide wires face challenges in effectively navigating vascular lesions due to limitations in rotation transmission performance and perforation capabilities, particularly at stenotic and completely occluded portions of blood vessels.
Innovation Solution
The guide wire features a core with a combined truncated cone structure, where the diameter tapers from the proximal end to the distal end, and is inserted into an outer coil with a tapered shape, enhancing torsional force and rotation transmission performance by reducing the rotation angle at the proximal end and increasing the torsional moment at the distal end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional guide wire with uniform core structure is used, then the structure is simple, but the rotation transmission performance and perforation capability are insufficient
Solution Approach 1:
The core is divided into multiple sections along its length, with each section having different structural characteristics. The distal end portion has a first core structure optimized for perforation, while the proximal end portion has a second core structure optimized for rotation transmission, allowing each segment to perform its specific function effectively
Solution Approach 2:
Different portions of the core are given different properties: the distal end portion has higher flexibility and perforation capability, while the proximal end portion has higher stiffness and rotation transmission capability. This local differentiation of properties resolves the contradiction between simple structure and high performance
2Reliability
If the core is made stiffer to improve rotation transmission, then rotation transmission improves, but the ability to navigate vascular lesions decreases
Solution Approach 1:
The core is segmented into distal and proximal portions with different stiffness characteristics. The distal portion remains flexible to navigate lesions while the proximal portion is stiffer to transmit rotation, resolving the contradiction between navigation ability and rotation transmission
Solution Approach 2:
The core exhibits local quality variation along its length, with the distal end having lower stiffness for adaptability and the proximal end having higher stiffness for rotation transmission, allowing the single core to simultaneously satisfy both contradictory requirements
3Reliability
If a single layered coil structure is used, then the device complexity is low, but the perforation performance at completely occluded lesions is insufficient
Solution Approach 1:
The guide wire employs a nested coil structure where an inner coil is positioned within an outer coil. This nested configuration enhances perforation capability at occluded lesions while maintaining a relatively compact and manageable device structure
Solution Approach 2:
The coil structure uses composite construction with inner and outer coils that may have different material properties and structural characteristics, creating a composite system that achieves superior perforation performance compared to single-layer structures
Data Source
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AI summary
A distal end portion 2B of the core has a structure of a combined truncated cone 26 formed by connecting truncated cones satisfying a predetermined relational expression. An outer diameter ratio between the maximum outer diameter and the minimum outer diameter of the combined truncated cone 26 is greater than the outer diameter ratio between a large diameter proximal portion and a small diameter distal portion of an inner coil 4, and is greater than the outer diameter ratio between a large diameter proximal portion and a small diameter distal portion of the outer coil. Because of this, the rotation angle of the proximal side is reduced when rotation operation is performed and the torsional moment toward the distal end side is increased. Thus, the perforation performance at the completely occluded lesion can be improved.