Catheter Hub Welding via Bubble Irregularities
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Solution Overview
Problem
Existing methods for fixing a catheter shaft and hub, such as insert molding and adhesive bonding, face issues with deformation and uneven adhesive distribution, leading to reduced fixing strength due to axial center displacement and gap inconsistencies.
Innovation Solution
A catheter design featuring a tubular shaft with a welded hub that incorporates bubbles on both the shaft and hub surfaces, creating irregularities for a stronger, more secure connection through electromagnetic welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an insert molding method is used to fix the shaft to the hub, then the shaft and hub can be connected, but deformation of the shaft or displacement in axial center direction may occur, decreasing fixing strength
Solution Approach 1:
The invention introduces bubbles only at specific locations on the shaft and/or hub (not throughout the entire structure), creating localized irregularities at the welding interface. This local modification enhances coupling force where needed without causing overall deformation or displacement of the shaft assembly.
Solution Approach 2:
The bubbles create spherical or irregular curved surfaces on the shaft and hub welding surfaces. These curved, irregular surfaces increase the contact area and mechanical interlocking between the shaft and hub, thereby enhancing the coupling force and fixing strength without requiring high-pressure injection molding that could cause deformation.
2Strength
If adhesive bonding is used with a small gap between shaft and hub, then the components can be connected, but the adhesive cannot flow properly, leaving gaps and decreasing fixing strength
Solution Approach 1:
The invention replaces the chemical bonding mechanism of adhesives with a mechanical welding mechanism enhanced by bubble-induced irregularities. The bubbles create physical interlocking surfaces that are welded together, providing a mechanical bond that is stronger and more reliable than adhesive bonding, while being easier to manufacture consistently.
3Ease of manufacture
If adhesive bonding is used with a large gap between shaft and hub, then the components can be connected, but it is difficult to completely fill the gap, decreasing fixing strength
Solution Approach 1:
The invention changes the surface geometry parameters of the welding interface by introducing bubbles, creating irregularities that increase surface area and mechanical interlocking. This parameter modification allows for strong welding bonds even with larger gaps between components, as the bubbles provide physical anchors for the weld material to bond to.
4Manufacturing precision
If the shaft is pressed by a fixing pin during injection molding, then the shaft can be positioned, but deformation of the shaft may occur, decreasing fixing strength
Solution Approach 1:
The invention removes the fixing pin from the manufacturing process entirely, replacing it with a bubble-based welding interface. By extracting the mechanical constraint of the fixing pin, the method eliminates the source of shaft deformation while maintaining precise positioning through the bubble-induced irregularities that enhance welding coupling.
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
The bubble-irregularity interface enhances the coupling force between the shaft and hub, preventing detachment under pressure and tensile forces, ensuring a stable connection.
Implementation Method 1
the accommodation unit includes a hub welded surface that is directly welded to the shaft outer surface
Data Source
Figure 1~2
Figure 3~4
Figure 5(A)~5(B)
AI summary
Provided is a catheter capable of firmly fixing a shaft and a hub. A catheter (10) includes: a shaft (20) that is a tubular body in which a lumen (21) extending the shaft (20) from a distal end to a proximal end is formed, and that includes a shaft proximal surface (24) in which the lumen (21) is opened and a shaft outer surface (22) that is an outer peripheral surface of the tubular body; and a hub (40) attached to the proximal end of the shaft (20). The hub (40) includes a tubular accommodation unit (41) configured to accommodate the shaft (20), the accommodation unit (41) includes a hub welded surface (49) directly welded to the shaft outer surface (22), and at least one of the accommodation unit (41) and the hub (40) is formed with a plurality of bubbles at a position close to the hub welded surface (49).