Guide Wire Torque Transmissivity via Tubular Joint
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Solution Overview
Problem
Existing guide wires face challenges in achieving optimal torque transmissivity and kink resistance due to issues with central axis alignment, deformation at joint parts, and rigidity gaps between core shafts, which affect their operability and kink resistance when inserted into body organs.
Innovation Solution
A guide wire configuration featuring a first core shaft and a second core shaft with coinciding central axes, covered by a first tubular member and further covered by a second tubular member, which is fixed to both core shafts, reducing rigidity gaps and preventing deformation, thereby enhancing torque transmissivity and kink resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the first core shaft and second core shaft are joined by welding, then the connection strength is improved, but deformation such as bending occurs in the vicinity of the joint part, reducing kink resistance
Solution Approach 1:
A tubular joint member is introduced as an intermediary component between the first core shaft and second core shaft. This tubular member covers the joint part and has a rigidity lower than both core shafts, acting as a buffer that reduces stress concentration and prevents deformation at the welding location, thereby maintaining kink resistance while preserving connection strength.
Solution Approach 2:
The rigidity parameter of the joint covering structure is deliberately changed to be lower than that of the core shafts. This parameter change allows the covering structure to flex under stress, preventing the transmission of deformation to the core shafts while still providing protective coverage over the welded joint.
2Ease of manufacture
If notches are provided in the core shafts for joining, then the connection is facilitated, but the central axes of the first and second core shafts cannot coincide, reducing torque transmissivity
Solution Approach 1:
The tubular joint member serves as a mediator that encloses the notched joint region. By covering the notches and joint area, it masks the misalignment caused by notching, allowing the core shafts to be joined more easily while the tubular member ensures that the external geometry maintains proper central axis alignment for torque transmission.
3Stability of the object's composition
If the joint part is covered by an annular or tubular member, then the kink resistance is improved, but the rigidity gap between core shafts remains, affecting operability
Solution Approach 1:
The rigidity of the tubular joint member is specifically designed to be lower than both core shafts. This creates a gradient of rigidity parameters that allows the joint region to flex independently, reducing the rigidity gap effect and improving torque transmission while the covering structure still provides kink protection.
Data Source
AI summary
A guide wire includes a first core shaft, a second core shaft, a first tubular member, and a second tubular member. The first tubular member is disposed to cover (i) a contact portion where the first core shaft and the second core shaft are arranged opposite to each other so that their central axes coincide, and (ii) a part of each of the first core shaft and the second core shaft, the part being adjacent to the contact portion. The second tubular member, having a tubular shape, covers at least the first tubular member and is fixed to both the first core shaft and the second core shaft.