Intravascular Blood Pump Bearing Structure for Low-Friction Support
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Solution Overview
Problem
Intravascular blood pumps face challenges in achieving low friction and high durability for the rotor and drive shaft bearings, particularly during high-speed rotation, which affects their efficiency and longevity.
Innovation Solution
The design incorporates a proximal bearing with a bearing sleeve and outer bearing ring, where the bearing sleeve forms an axial and radial bearing with the outer ring, and is connected to the flexible drive shaft, allowing for low friction and high durability through the use of a purge fluid and sealant, and materials like ceramic and metal, ensuring stable support and reduced frictional contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a bearing is used to support the drive shaft and rotor during high-speed rotation, then the pump can operate at significant rotational speeds, but friction and wear occur reducing durability
Solution Approach 1:
A purge fluid is introduced as an intermediary substance between the bearing components (drive shaft and bearing surfaces). The purge fluid flows through the bearing assembly, creating a fluid film that separates the rotating drive shaft from the stationary bearing surfaces, thereby reducing direct frictional contact and wear while enabling high-speed rotation
Solution Approach 2:
The patent employs hydrodynamic lubrication by introducing a purge fluid (liquid) through the bearing assembly. The fluid flow creates pressure and forms a lubricating film between moving and stationary components, replacing direct solid-to-solid contact with fluid-mediated contact, which significantly reduces friction and extends bearing durability during high-speed operation
2Adaptability or versatility
If the bearing is exposed to the intravascular environment, then the pump can be inserted percutaneously into blood vessels, but blood can enter the bearing causing friction increase and damage
Solution Approach 1:
The purge fluid acts as an intermediary barrier between the intravascular environment (blood) and the bearing components. By continuously flowing through the bearing assembly, the purge fluid prevents blood from contacting the bearing surfaces, maintaining low friction conditions and preventing blood-related damage while allowing percutaneous insertion into blood vessels
Solution Approach 2:
A hydraulic seal is created using the purge fluid flow through the bearing assembly. The pressurized purge fluid forms a protective barrier that prevents blood from penetrating into the bearing region, effectively isolating the bearing from the intravascular environment while maintaining the pump's percutaneous insertability
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
This configuration reduces friction, prevents blood from entering the bearing, and allows for higher rotational speeds and longer pump lifetime by maintaining low friction and high durability, enhancing the overall performance and reliability of the intravascular blood pump.
Implementation Method 1
a purge fluid is provided to flow through the gap defined by the radial bearing
Implementation Method 2
the proximal portion of the bearing sleeve forms an axial bearing with a proximal surface of the outer bearing ring. The bearing sleeve further comprises a distal portion extending from the proximal portion of the sleeve distally into the outer bearing ring, wherein the distal portion of the bearing sleeve forms a radial bearing with the outer bearing ring
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An intravascular blood pump (1) comprises a catheter (5), a rotor (10), a housing (11) in which the rotor (10) is housed and a flexible drive shaft (12) extending through the catheter (5) and rotatably supported in a proximal bearing (13) located proximally of the rotor (10). The proximal bearing (13) comprises a bearing sleeve (30) and an outer bearing ring (32). The bearing sleeve (30) comprises a proximal portion located proximally of the outer bearing ring (32), the proximal portion of the bearing sleeve (30) forming an axial bearing with a proximal surface of the outer bearing ring (32). The bearing sleeve (30) further comprises a distal portion extending from the proximal portion of the bearing sleeve (30) distally into the outer bearing ring (32), wherein the distal portion of the bearing sleeve (30) forms a radial bearing with the outer bearing ring (32).