Axial flow blood pump
The invention generally relates to improved medical blood pump devices, systems, and methods. For example, blood pumps may be provided that include a housing defining a blood flow path between an inlet and an outlet. A rotor may be positioned in the blood flow path. A motor stator may be driven to rotate the rotor to provide the blood flow through the pump. Axial and/or tilt stabilization components may be provided to increase an axial and/or tilt stabilization of the rotor within the blood flow path. In some embodiments, biasing forces are provided that urge the rotor toward a bearing component. The biasing force may be provided by adjusting drive signals of the motor stator. Additionally, or alternatively, one or more magnets (e.g., permanent/stator magnets) may be provided to bias the rotor in the upstream and/or downstream direction (e.g., toward a bearing (chamfer, step, conical), or the like).
1. A blood pump comprising:
a housing with an inner wall defining an inlet, an outlet downstream from the inlet, and a blood flow path between the inlet and the outlet;
an impeller comprising a magnetic material positioned within the blood flow path;
a motor stator positioned about the blood flow path between the inlet and the outlet, the motor stator, during operation, configured to generate a magnetic field for suspending the impeller within the blood flow path;
a first tapered bearing extending from the inner wall of the housing and into the blood flow path, wherein a tapered portion of the impeller cooperates with the first tapered bearing to provide increased stabilization of the impeller in a tilt direction;
wherein the magnetic field urges the impeller toward the first tapered bearing so as to stabilize the impeller in an axial direction.
2. The blood pump of claim 1 , wherein the magnetic field of the motor stator urging the impeller toward the first tapered bearing and axial hydrodynamic forces between the impeller and the first tapered bearing are configured to provide increased stabilization of the impeller in the axial direction.
3. The blood pump of claim 1 , wherein the impeller has a hub with a conical upstream portion configured to cooperate with the first tapered bearing to provide increased stabilization of the impeller in the tilt direction.
4. The blood pump of claim 1 , wherein the first tapered bearing is conical in shape.
5. The blood pump of claim 1 , wherein the impeller has a hub with a conical downstream portion configured to cooperate with the first tapered bearing to provide increased stabilization of the impeller in the tilt direction.
6. The blood pump of claim 1 , wherein the impeller further comprises blades extending radially from a hub, the blades comprising beveled downstream edges configured to cooperate with the first tapered bearing to provide increased stabilization of the impeller in the tilt direction.
7. The blood pump of claim 1 , further comprising:
a first permanent magnet producing a first permanent magnetic field urging the impeller in a direction along a flow direction of the blood flow path; and
a second permanent magnet producing a second permanent magnetic field urging the impeller in a direction opposite the flow direction of the blood flow path;
wherein the first and second permanent magnetic fields of the first permanent magnet and the second permanent magnet are configured to provide further increased stabilization of the impeller in the axial direction.
8. The blood pump of claim 7 , further comprising a yoke disposed about the motor stator, the yoke configured to increase a magnetic flux density of the motor stator.
9. The blood pump of claim 7 , further comprising a yoke disposed about the first permanent magnet, the yoke configured to increase a magnetic flux density of the first permanent magnet.
10. The blood pump of claim 7 , further comprising a yoke disposed about the second permanent magnet, the yoke configured to increase a magnetic flux density of the second permanent magnet.
11. The blood pump of claim 1 , further comprising a second tapered bearing extending from the inner wall of the housing and into the blood flow path, the second tapered bearing positioned downstream from the first tapered bearing; and wherein an upstream portion of the impeller cooperates with the first tapered bearing and a downstream portion of the impeller cooperates with the second tapered bearing to provide increased stabilization of the impeller in the tilt direction.
12. The blood pump of claim 1 , wherein the axial direction is along a flow direction of the blood flow path.
13. The blood pump of claim 1 , wherein the axial direction is opposite a flow direction of the blood flow path.
14. A method of operating a blood pump having a housing with an inner wall defining an inlet, an outlet downstream from the inlet, an impeller, a blood flow path between the inlet and the outlet, and a first tapered bearing extending from the inner wall of the housing and into the blood flow path, the method comprising:
operating a motor stator positioned about the blood flow path between the inlet and the outlet to generate a magnetic field for suspending the impeller within the blood flow path, wherein the magnetic field urges the impeller toward the first tapered bearing so as to stabilize the impeller in an axial direction;
causing a first tapered portion of the impeller to cooperate with the first tapered bearing to provide increased stabilization of the impeller in a tilt direction.
15. The method of claim 14 , wherein the blood pump further comprises a second tapered bearing extending from the inner wall of the housing and into the blood flow path, the method further comprising causing a second tapered portion of the impeller to cooperate with the second tapered bearing to provide further increased stabilization of the impeller in the tilt direction.
16. The method of claim 14 , wherein the impeller further comprises blades extending radially from a hub, the blades comprising beveled downstream edges configured to cooperate with the first tapered bearing to provide increased stabilization of the impeller in the tilt direction.
17. The blood pump of claim 14 , further comprising:
producing, by a first permanent magnet, a first permanent magnetic field urging the impeller in a direction along a flow direction of the blood flow path; and
producing, by a second permanent magnet, a second permanent magnetic field urging the impeller in a direction opposite the flow direction of the blood flow path;
wherein the first and second permanent magnetic fields of the first permanent magnet and the second permanent magnet are configured to provide further increased stabilization of the impeller in the axial direction.
18. The method of claim 17 , wherein the blood pump further comprises a yoke disposed about the motor stator, the method further comprising: increasing, by the yoke, a magnetic flux density of the motor stator.
19. The method of claim 17 , wherein the blood pump further comprises a yoke disposed about the first permanent magnet, the method further comprising: increasing, by the yoke, a magnetic flux density of the first permanent magnet.
20. The method of claim 17 , wherein the blood pump further comprises a yoke disposed about the second permanent magnet, the method further comprising: increasing, by the yoke, a magnetic flux density of the second permanent magnet.