Perfused Flexible Shaft Structure for Wear Particle Isolation
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Solution Overview
Problem
Existing flexible shaft structures for interventional medical devices face challenges in insulating wear particles, reducing vibration and noise, and managing perfusion flow effectively, especially under high-speed rotation, due to limitations in size, torque transmission, and complexity of existing solutions.
Innovation Solution
A flexible shaft structure with a constraint insulator and outer sheath tube, featuring an inner and outer constraint layer, insulation layer, and perfusion cavities, which supplies cooling/lubricating fluid to the shaft, insulates wear particles, and reduces vibration and noise through perfusion-based sealing and lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional flexible shaft structures are used in interventional medical devices, then the device can transmit torque, but wear particles are generated and cannot be effectively insulated
Solution Approach 1:
The flexible shaft is divided into multiple segments with independent constraint layers and insulation layers. Each segment contains its own wear particle insulation system, allowing localized containment of wear particles while maintaining overall shaft flexibility and torque transmission capability.
Solution Approach 2:
A perfusion fluid is introduced as an intermediary substance between the flexible shaft components. This fluid serves multiple functions: lubricating the shaft to reduce wear particle generation, cooling the shaft to prevent material degradation, and potentially flushing away generated wear particles, thereby enhancing the insulation effectiveness.
2Power
If the flexible shaft operates at high speed, then torque transmission is improved, but vibration and noise increase
Solution Approach 1:
Damping materials and vibration-absorbing structures are pre-installed within the flexible shaft assembly before operation. These elements are positioned to counteract vibrations and noise generated during high-speed torque transmission, reducing harmful effects before they propagate to the surrounding environment and patient tissue.
Solution Approach 2:
The shaft design incorporates variable stiffness segments and adjustable damping characteristics that can be optimized for different operating speeds. By changing structural parameters such as layer thickness, material properties, and constraint layer spacing, the shaft maintains stable operation across a range of speeds while minimizing vibration and noise.
3Stability of the object's composition
If additional constraint structures are added to reduce friction and stabilize the shaft, then shaft centering is improved, but device complexity increases
Solution Approach 1:
The constraint layers and insulation layers are designed to serve multiple functions simultaneously. The constraint layers provide shaft centering and structural support, while the insulation layers contain wear particles and provide thermal isolation. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity despite added stabilization capabilities.
Solution Approach 2:
The flexible shaft employs a nested structure where constraint layers, insulation layers, and perfusion channels are concentrically arranged around the central shaft. This nested configuration maximizes the use of available space, allowing multiple functional layers to coexist without proportionally increasing the overall device diameter or complexity.
4Object-generated harmful factors
If perfusion flushing is used to remove wear particles, then particle insulation is improved, but perfusate consumption increases
Solution Approach 1:
Instead of continuous high-volume perfusion flushing, the system uses partial or intermittent perfusion at optimized flow rates. The perfusion fluid is introduced at specific locations and timing to effectively remove wear particles when needed, rather than continuously, thereby reducing overall perfusate consumption while maintaining adequate insulation effectiveness.
Solution Approach 2:
The flexible shaft design incorporates self-lubricating materials and low-friction surfaces that reduce wear particle generation at the source. By minimizing wear through material selection and surface engineering, the system reduces the amount of perfusion fluid needed for particle removal, allowing the system to serve itself by reducing wear rather than relying solely on active flushing.
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 solution provides effective insulation of wear particles, stability, and consistency of perfusion flow, reduces noise and vibration, and simplifies perfusion control, using less perfusate and reducing operational burdens, while maintaining high precision and reliability in perfusion flow management.
Implementation Method 1
a perfusion inflow annular cavity is formed between the outer constraint layer and the outer sheath tube and between the outer constraint layer and the insulation layer
Implementation Method 2
supply cooling/lubricating liquid to a flexible transmission shaft
Implementation Method 3
effectively insulate generated wear particles, prevent the wear particles from entering a patient body
Implementation Method 4
reduce vibration and noise of the flexible shaft under high-speed rotation
Data Source
AI summary
The present invention discloses a flexible shaft structure insulating wear particles by perfusion, which includes a flexible transmission shaft, a proximal holder is provided at one end of the flexible transmission shaft, a distal holder is provided at the other end of the flexible transmission shaft, a constraint insulator and an outer sheath tube are provided outside the flexible transmission shaft, and the constraint insulator sequentially includes an inner constraint layer, an insulation layer and an outer constraint layer from inside to outside; a perfusion inflow annular cavity is formed between the outer constraint layer and the outer sheath tube and between the outer constraint layer and the insulation layer, respectively, and a static sealed inner cavity is formed between the inner constraint layer and the insulation layer and between the inner constraint layer and the flexible transmission shaft, respectively; the proximal holder is provided with a perfusion inlet pipeline communicated with the perfusion inflow annular cavity and a perfusion exhaust pipeline communicated with the static sealed inner cavity; and the distal holder is provided with a perfusion insulation cavity. According to the present invention, the generated wear particles can be effectively insulated, the stability and consistency of perfusion flow of the product are improved, and the problems of vibration and noise of the flexible shaft under high-speed rotation are solved.