Heart pump drive and bearing

Abstract

A heart pump including a housing defining a cavity including at least one inlet aligned with an axis of the cavity and at least one outlet provided in a circumferential outer wall of the cavity. An impeller is provided within the cavity, the impeller including a rotor and vanes mounted on the rotor for urging fluid from the inlet radially outwardly to the outlet. A drive is provided for rotating the impeller in the cavity, the drive including a plurality of circumferentially spaced permanent drive magnets mounted within and proximate a first face of the rotor, adjacent drive magnets having opposing polarities and a plurality of circumferentially spaced drive coils mounted within the housing proximate a first end of the cavity, each coil being wound on a respective drive stator pole of a drive stator and being substantially radially aligned with the drive magnets, the drive coils being configured to generate a drive magnetic field that cooperates with the drive magnets to thereby rotate the impeller. A magnetic bearing is also provided to thereby at least one of control an axial position of the impeller and at least partially restrain radial movement of the impeller.

What is claimed is: 
     
         1 )- 58 ) (canceled) 
     
     
         59 ) A heart pump including:
 a) a housing defining a cavity including:
 i) at least one inlet aligned with an axis of the cavity; and, 
 ii) at least one outlet provided in a circumferential outer wall of the cavity; 
   b) an impeller provided within the cavity, the impeller including a rotor and vanes mounted on the rotor for urging fluid from the inlet radially outwardly to the outlet;   c) a drive for rotating the impeller in the cavity, the drive including:
 i) a plurality of circumferentially spaced permanent drive magnets mounted within and proximate a first face of the rotor; and, 
 ii) a plurality of circumferentially spaced drive coils mounted within the housing proximate a first end of the cavity, and wherein vanes of the impeller and the first end of the housing cooperate to define a hydrodynamic bearing. 
   
     
     
         60 ) A heart pump according to  claim 59 , wherein the hydrodynamic bearing is defined by an upper surface of the vanes of the impeller facing the first end of the cavity. 
     
     
         61 ) A heart pump according to  claim 60 , wherein the upper surface includes a leading ramp and a trailing flat pad. 
     
     
         62 ) A heart pump according to  claim 61 , wherein at least one of:
 a) the flat pad has an inner radius of at least one of:
 i) between 16 mm and 22 mm; and, 
 ii) between 18 mm and 20 mm; 
   b) the flat pad has a length of at least one of:
 i) between 1 mm and 5 mm; 
 ii) between 2 mm and 4 mm; and, 
 iii) about 3 mm; 
   c) the ramp has a length of at least one of:
 i) between 5 mm and 15 mm; 
 ii) between 8 mm and 12 mm; and, 
 iii) about 10 mm; and, 
   d) the ramp has a height of at least one of:
 i) between 0.02 mm and 0.1 mm; 
 ii) between 0.04 mm and 0.08 mm; and, 
 iii) about 0.06 mm. 
   
     
     
         63 ) A heart pump according to  claim 60 , wherein the vanes at least one of:
 a) has an inner radius that is at least one of:
 i) between 10 mm and 20 mm; 
 ii) between 12 mm and 18 mm, 
 iii) between 14 mm and 16 mm; and, 
 iv) about 15 mm; 
   b) an outer radius that is at least one of:
 i) between 20 mm and 30 mm; 
 ii) between 22 mm and 28 mm; 
 iii) between 24 mm and 26 mm; and, 
 iv) about 25 mm. 
   
     
     
         64 ) A heart pump according to a  claim 59 , wherein the heart pump includes a magnetic bearing to at least one of control an axial position of the impeller and at least partially restrain radial movement of the impeller, and wherein the hydrodynamic bearing is configured to operate if the magnetic bearing fails. 
     
     
         65 ) A heart pump according to  claim 59 , wherein the heart pump includes a controller that controls operation of the drive and bearing in use. 
     
     
         66 ) A heart pump according to  claim 65 , wherein the controller includes a processor operating in accordance with software instructions stored in a memory. 
     
     
         67 ) A heart pump according to  claim 65 , wherein the controller controls the drive to selectively generate an axial attractive force. 
     
     
         68 ) A heart pump according to  claim 67 , wherein the controller controls the drive to generate the axial attractive force to at least one of:
 a) move the impeller within the cavity; and,   b) increase shock resistance when operating using a hydrodynamic bearing in the event that the magnetic bearing fails.   
     
     
         69 ) A heart pump according to  claim 67 , wherein the controller:
 a) detects at least one of:
 i) failure of the magnetic bearing; and, 
 ii) movement of the impeller to the second end of the cavity when the magnetic bearing has failed; and, 
   b) controls the drive to generate the axial attractive force in response to the detection.   
     
     
         70 ) A heart pump according to  claim 69 , wherein the controller detects failure of the magnetic bearing based on at least one of:
 a) a bearing indicator indicative of a current used by the magnetic bearing;   b) a drive indicator indicative of a current used by the drive; and,   c) sensor signals.   
     
     
         71 ) A heart pump according to  claim 59 , wherein the drive and rotor are arranged such that, at least one of:
 a) a spacing between the first face of the rotor and the first end of the cavity is at least one of:
 i) between 2 mm and 5 mm in use; 
 ii) between 2 mm and 3 mm in use; and, 
 iii) approximately 2.3 mm in use; 
   b) a spacing between a drive stator pole face and drive magnet face is at least one of:
 i) between 2.5 mm and 6 mm in use; 
 ii) between 2.5 mm and 4 mm in use; and, 
 iii) approximately 3.2 mm in use; 
   c) a spacing between a drive stator yoke and drive magnet yoke is at least one of:
 i) between 7 mm and 25 mm in use; 
 ii) between 8 mm and 20 mm in use; and, 
 iii) approximately 17 mm in use; and, 
   d) a spacing between a drive stator pole face and drive magnet yoke is at least one of:
 i) between 4 mm and 8 mm in use; 
 ii) between 4.5 mm and 7 mm in use; and, 
 iii) approximately 5.8 mm in use. 
   
     
     
         72 ) A heart pump according to  claim 59 , wherein the vanes have a height of at least one of:
 a) between 1.5 mm and 5 mm;   b) between 1.5 mm and 2.5 mm;   c) between 1.8 mm and 2.2 mm;   d) about 2 mm.   
     
     
         73 ) A heart pump according to  claim 59 , wherein the impeller includes first and second sets of vanes provided on a rotor body, the rotor being positioned within the cavity to define:
 a) a first cavity portion having a first inlet and a first outlet, the first set of vanes being provided within the first cavity portion so as to define a first pump that provides at least partial left ventricular function; and,   b) a second cavity portion having a second inlet and a second outlet, the second set of vanes being provided within the second cavity portion so as to define a second pump that provides at least partial right ventricular function.   
     
     
         74 ) A heart pump according to  claim 73 , wherein the heart pump is a total artificial heart. 
     
     
         75 ) A heart pump according to  claim 73 , wherein the axial position of the impeller determines a separation between each set of vanes and a respective cavity surface, the separation being used to control the fluid flows from the inlets to the outlets. 
     
     
         76 ) A heart pump including:
 a) a housing defining a cavity including:
 i) at least one inlet aligned with an axis of the cavity; and, 
 ii) at least one outlet provided in a circumferential outer wall of the cavity; 
   b) an impeller provided within the cavity, the impeller including a rotor and vanes mounted on the rotor for urging fluid from the inlet radially outwardly to the outlet;   c) a drive for rotating the impeller in the cavity, the drive including:
 i) a plurality of circumferentially spaced permanent drive magnets mounted within and proximate a first face of the rotor; and, 
 ii) a plurality of circumferentially spaced drive coils mounted within the housing proximate a first end of the cavity, each coil being wound on a respective drive stator pole of a drive stator and being substantially radially aligned with the drive magnets, the drive coils being configured to generate a drive magnetic field that cooperates with the drive magnets to thereby rotate the impeller. 
   
     
     
         77 ) A heart pump according to  claim 76 , the heart pump further including a bearing for supporting the impeller within the cavity, the bearing being at least one of:
 a) a magnetic bearing;   b) a hydrodynamic bearing; and,   c) a physical bearing.