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 comprising an inner wall surface defining an inlet, an outlet downstream from the inlet, and a blood flow channel between the inlet and the outlet;
an impeller comprising a magnetic material and positioned within the blood flow channel;
a motor stator positioned about the blood flow channel between the inlet and the outlet, wherein the motor stator is operable to magnetically suspend and rotate the impeller within the blood flow channel to pump blood through the blood flow channel in a downstream direction;
a first permanent magnet producing a first permanent magnetic field urging the impeller in the downstream direction;
a second permanent magnet producing a second permanent magnetic field urging the impeller in an upstream direction that is opposite to the downstream direction;
wherein the first permanent magnetic field and the second permanent magnetic field are configured to provide increased stabilization of the impeller in an axial direction.
2 . The blood pump of claim 1 , wherein the first permanent magnet and the second permanent magnet comprise ring magnets positioned about the blood flow channel.
3 . The blood pump of claim 1 , further comprising a first conical bearing; and wherein the impeller cooperates with the first conical bearing to provide increased stabilization of the impeller in a tilt direction.
4 . The blood pump of claim 3 , wherein the impeller has a hub with a conical upstream portion configured to cooperate with the first conical bearing to provide increased stabilization of the impeller in the tilt direction.
5 . The blood pump of claim 4 , wherein the first conical bearing comprises a surface angled at 45 degrees relative to an axis of rotation of the impeller to provide radial and axial hydrodynamic forces; and wherein a surface of the conical upstream portion of the hub angles toward the axis of rotation of the impeller at 45 degrees; wherein the radial and axial hydrodynamic forces between the surface of the first conical bearing and the surface of the conical upstream portion of the hub increases stabilization of the impeller in the tilt direction and the axial direction.
6 . The blood pump of claim 3 , wherein the impeller has a hub with a conical downstream portion configured to cooperate with the first conical bearing to provide increased stabilization of the impeller in the tilt direction.
7 . The blood pump of claim 6 , wherein the first conical bearing comprises a surface angled at 45 degrees relative to an axis of rotation of the impeller to provide radial and axial hydrodynamic forces; and wherein a surface of the conical downstream portion of the hub angles toward the axis of rotation of the impeller at 45 degrees; wherein the radial and axial hydrodynamic forces between the surface of the first conical bearing and the surface of the conical downstream portion of the hub increases stabilization of the impeller in the tilt direction and the axial direction.
8 . The blood pump of claim 3 , wherein the impeller comprises blades extending radially from a hub, the blades comprising beveled upstream edges configured to cooperate with the first conical bearing to provide increased stabilization of the impeller in the tilt direction.
9 . The blood pump of claim 8 , wherein the first conical bearing comprises a surface angled at 45 degrees relative to an axis of rotation of the impeller to provide radial and axial hydrodynamic forces; and wherein blade tips of beveled upstream edges of the blades of the impeller angle toward the axis of rotation of the impeller at 45 degrees; wherein the radial and axial hydrodynamic forces between the surface of the first conical bearing and blade tips of beveled upstream edges of the blades of the impeller increases stabilization of the impeller in the tilt direction and the axial direction.
10 . The blood pump of claim 3 , further comprising a second conical bearing positioned downstream from the first conical bearing; and wherein an upstream portion of the impeller cooperates with the first conical bearing and a downstream portion of the impeller cooperates with the second conical bearing to provide increased stabilization of the impeller in the tilt direction.
11 . The blood pump of claim 3 , wherein the first permanent magnetic field and the second permanent magnetic field cumulatively urge the impeller towards the first conical bearing.
12 . The blood pump of claim 1 , further comprising a yoke disposed about the motor stator, the yoke configured to increase a magnetic flux density of the motor stator.
13 . The blood pump of claim 1 , further comprising a yoke disposed about the first permanent magnet, the yoke configured to increase a magnetic flux density of the first permanent magnet.
14 . The blood pump of claim 1 , further comprising a yoke disposed about the second permanent magnet, the yoke configured to increase a magnetic flux density of the second permanent magnet.
15 . The blood pump of claim 1 , wherein a first portion of the inner wall surface has a first inner dimension that increases to a second inner dimension in a downstream direction; and wherein the impeller has an outer dimension that is greater than the first inner dimension of the inner wall surface such that the first portion of the inner wall surface prevents the impeller from advancing upstream of the first portion of the inner wall surface.
16 . The blood pump of claim 15 , wherein the first permanent magnetic field and the second permanent magnetic field cumulatively urge the impeller in an upstream direction towards the first portion of the inner wall surface.
17 . The blood pump of claim 15 , wherein the motor stator magnetically urges the impeller in an upstream direction toward the first portion of the inner wall surface.
18 . A blood pump comprising:
a housing comprising an inner wall surface defining an inlet, an outlet downstream from the inlet, and a blood flow channel between the inlet and the outlet;
an impeller comprising a magnetic material, wherein the impeller is positioned within the blood flow channel;
a motor stator positioned about the blood flow channel between the inlet and the outlet, wherein the motor stator is operable to magnetically suspend and rotate the impeller within the blood flow channel to pump blood through the blood flow channel in a downstream direction;
a bearing surface that cooperates with the impeller to provide hydrodynamic forces to provide increased stabilization of the impeller within the blood flow channel;
a first permanent magnet producing a first permanent magnetic field urging the impeller in the downstream direction; and
a second permanent magnet producing a second permanent magnetic field urging the impeller in an upstream direction that is opposite to the downstream direction;
wherein the first permanent magnetic field and the second permanent magnetic field are configured to provide increased stabilization of the impeller in an axial direction.
19 . A blood pump comprising:
a housing comprising an inner wall surface defining an inlet, an outlet downstream from the inlet, and a blood flow channel between the inlet and the outlet;
an axial flow impeller comprising a magnetic material, wherein the axial flow impeller is positioned within the blood flow channel;
a motor stator positioned about the blood flow channel between the inlet and the outlet, wherein the motor stator is operable to magnetically suspend and rotate the axial flow impeller within the blood flow channel to pump blood through the blood flow channel;
a first permanent magnet producing a first permanent magnetic field urging the axial flow impeller in a first direction;
a second permanent magnet producing a second permanent magnetic field urging the axial flow impeller in a second direction that is opposite to the first direction;
wherein the first permanent magnetic field and the second permanent magnetic field are configured to provide increased axial stabilization of the axial flow impeller.