Intravascular Blood Pump Drive Layout for Compact Magnetic Coupling
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Solution Overview
Problem
Existing blood pumps, particularly intravascular blood pumps, have a large outer diameter due to the need for strong magnetic coupling between the drive unit and the impeller, which limits their ability to be inserted transvascularly or transvalvularly.
Innovation Solution
A blood pump design featuring a drive unit with a plurality of posts arranged about the axis of rotation, each with a shaft and head portion, and a magnetic coupling mechanism using coil windings and magnets to create a rotating magnetic field, reducing the number of moving parts and allowing for a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If large magnets are provided to achieve sufficiently strong magnetic coupling, then the magnetic forces are high enough, but the overall diameter of the blood pump becomes large
Solution Approach 1:
The drive unit is segmented into multiple independent posts (at least two, preferably three or more) arranged around the axis of rotation. Each post carries a coil winding and acts as a separate magnetic core. This segmentation allows the magnetic field to be generated in a distributed manner, creating a rotating magnetic field that provides sufficient coupling force without requiring large single magnets, thereby reducing the overall pump diameter.
Solution Approach 2:
The system transitions from static magnets to a dynamic rotating magnetic field generated by sequentially energizing coil windings on multiple posts. This dynamic approach allows the magnetic field to rotate and maintain effective coupling with the impeller magnets throughout the rotation cycle, providing sufficient magnetic force with smaller magnet sizes and reduced pump diameter.
2Force
If high current is supplied to the drive unit to achieve strong magnetic coupling, then the magnetic forces are high enough, but the overall diameter of the blood pump increases
Solution Approach 1:
The drive unit is divided into multiple posts with individual coil windings. By distributing the magnetic field generation across multiple segments, the system can achieve the required total magnetic force through coordinated activation of multiple smaller coils rather than relying on a single large magnet or excessive current in one coil, thus maintaining a compact pump diameter.
Solution Approach 2:
The control unit sequentially supplies voltage to the coil windings in a periodic manner to create a rotating magnetic field. This periodic activation of different coil sets allows the magnetic field to rotate and maintain effective coupling throughout the impeller rotation, achieving sufficient magnetic force with moderate current levels and compact dimensions.
3Device complexity
If the number of moving parts is reduced by using a rotating magnetic field, then the device complexity is reduced, but the magnetic coupling strength may be insufficient
Solution Approach 1:
The drive unit is segmented into multiple posts with coil windings that can be independently controlled. This segmentation enables the creation of a rotating magnetic field through sequential activation, maintaining strong magnetic coupling force while eliminating the need for complex mechanical transmission components and reducing the number of moving parts.
Solution Approach 2:
The invention replaces mechanical transmission systems with an electromagnetic field-based rotating magnetic field mechanism. By using sequentially energized coil windings on multiple posts to generate a rotating magnetic field, the system achieves impeller rotation without mechanical contacts or complex moving parts, reducing device complexity while maintaining effective magnetic 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 design achieves a compact outer diameter suitable for intravascular insertion, enabling high-speed operation with reduced wear and improved alignment of the impeller, while maintaining efficient magnetic coupling and structural stability.
Implementation Method 1
A coil winding is disposed about the shaft portion of each of the posts, with the coil windings being sequentially controllable so as to create the rotating magnetic field
Implementation Method 2
The impeller comprises at least one magnet, which is arranged to magnetically couple the impeller to the drive unit, i.e., to interact with the rotating magnetic field so as to cause rotation of the impeller
Data Source
AI summary
An intravascular blood pump comprises a pump casing having a blood flow inlet and a blood flow outlet, and an impeller arranged in said pump casing so as to be rotatable about an axis of rotation, wherein the impeller has blades sized and shaped for conveying blood from the blood flow inlet to the blood flow outlet. The blood pump further comprises a drive unit for rotating the impeller, the drive unit comprising a plurality of posts arranged about the axis of rotation, wherein each of the posts includes a shaft portion and a head portion. Coil windings around the posts are sequentially controllable so as to create a rotating magnetic field. The drive unit further comprises a back plate which engages ends of the shaft portions of the posts opposite the head portions.