Centrifugal pump apparatus

• US 9,638,202 B2
• Filed: 06/06/2016
• Issued: 05/02/2017
• Est. Priority Date: 09/14/2010
• Status: Active Grant

• Current Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Original Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Inventors: Ozaki, Takayoshi, Yamada, Hiroyuki, Sugiura, Ken
• Primary Examiner(s): Hamo, Patrick
• Application Number:
  US15/174,639
• Publication Number:
  US 20160281728A1
• Time in Patent Office: 330 Days
• CPC Class Codes: A61M 60/117 for assisting the heart, e.g. transcutaneous or external ventricular assist devices
• CPC Class Codes: A61M 60/148 in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/232 Centrifugal pumps
• CPC Class Codes: A61M 60/419 the force acting on the blood contacting member being permanent magnetic, e.g. from a rotating magnetic coupling between driving and driven magnets
• CPC Class Codes: A61M 60/422 the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps
• CPC Class Codes: A61M 60/804 Impellers
• CPC Class Codes: A61M 60/822 specially adapted for being actively controlled
• CPC Class Codes: A61M 60/824 Hydrodynamic or fluid film bearings
• CPC Class Codes: F04D 1/04 Helico-centrifugal pumps
• CPC Class Codes: F04D 13/064 Details of the magnetic circuit
• CPC Class Codes: F04D 13/0666 the motor being of the plane gap type
• CPC Class Codes: F04D 29/0473 for radial pumps
• CPC Class Codes: F04D 29/048 magnetic; electromagnetic
• CPC Class Codes: F04D 29/22 specially for centrifugal pumps
• CPC Class Codes: F04D 7/04 the fluids being viscous or non-homogenous
• CPC Class Codes: H02K 21/24 with magnets axially facing the armatures, e.g. hub-type cycle dynamos
• CPC Class Codes: H02K 2205/03 Machines characterised by thrust bearings
• CPC Class Codes: H02K 2213/03 Machines characterised by numerical values, ranges, mathematical expressions or similar information
• CPC Class Codes: H02K 5/12 specially adapted for operating in liquid or gas combined with cooling arrangements H02K9/00
• CPC Class Codes: H02K 7/09 with magnetic bearings

Abstract

A centrifugal blood pump apparatus includes a plurality of permanent magnets (17) in an impeller (10) in a blood chamber (7), a plurality of coils (20) in a motor chamber (8), and a magnetic element (18) in each of the coils (20). The magnetic elements (18) are made shorter than the coils (20) to lower attractive force between the magnetic elements (18) and the permanent magnets (17) in the impeller (10), to set a large gap between the magnetic elements (18) and the permanent magnets (17). As a result, axial attractive force and negative rigidity can be lowered while required torque is satisfied.

Claims

1. A centrifugal pump apparatus including a housing having first and second chambers partitioned from each other by a dividing wall, an impeller rotatably provided in said first chamber along said dividing wall, for delivering fluid by centrifugal force during rotation, and a drive unit provided in said second chamber for driving said impeller to rotate, comprising:

a first magnetic element provided in one surface of said impeller;

a second magnetic element provided in an inner wall of said first chamber facing the one surface of said impeller, for attracting said first magnetic element; and

a plurality of third magnetic elements provided in an other surface of said impeller, arranged in a direction of rotation of said impeller, and attracted by said drive unit, wherein;

said drive unit includes

a plurality of coils provided to face said plurality of third magnetic elements, for generating a rotating magnetic field,

a plurality of fourth magnetic elements provided in correspondence with said plurality of coils respectively and each inserted in the corresponding coil,

each said fourth magnetic element is shorter than the corresponding coil in a direction of a central axis of said impeller,

during rotation of said impeller, a first attractive force between said first and second magnetic elements and a second attractive force between said plurality of third magnetic elements and said plurality of fourth magnetic elements are balanced with each other substantially in a center of a movable range of said impeller in said first chamber,

a first groove for hydrodynamic bearing is formed in one surface of said impeller or in the inner wall of said first chamber facing the one surface,

a second groove for hydrodynamic bearing is formed in the other surface of said impeller or in said dividing wall facing the other surface, and

each said fourth magnetic element includes a strip-shaped magnetic steel plate wound a plurality of times around a center line.

2. The centrifugal pump apparatus according to claim 1, wherein

said drive unit further includes a disc-shaped fifth magnetic element,

said plurality of coils are provided between said dividing wall and said fifth magnetic element, and

said plurality of fourth magnetic elements are joined to said fifth magnetic element.

3. The centrifugal pump apparatus according to claim 1, wherein each said fourth magnetic element is formed in a cylindrical shape.

4. The centrifugal pump apparatus according to claim 1, wherein each said fourth magnetic element is made of pure iron, soft iron, or ferrosilicon.

5. The centrifugal pump apparatus according to claim 1, wherein each said fourth magnetic element is made of powders of pure iron, soft iron, or ferrosilicon.

6. The centrifugal pump apparatus according to claim 1, wherein

a third groove for hydrodynamic bearing is formed in an outer circumferential surface of said impeller or in an inner circumferential surface of said first chamber facing the outer circumferential surface.

7. The centrifugal pump apparatus according to claim 1, wherein said fluid is blood, and said centrifugal pump apparatus is used for circulating said blood.

8. A centrifugal pump apparatus including a housing having first and second chambers partitioned from each other by a dividing wall, an impeller rotatably provided in said first chamber along said dividing wall, for delivering fluid by centrifugal force during rotation, and a drive unit provided in said second chamber for driving said impeller to rotate, comprising

a plurality of first magnetic elements provided in said impeller, arranged in a direction of rotation of said impeller, and attracted by said drive unit, wherein

said drive unit includes

a plurality of coils provided to face said plurality of first magnetic elements, for generating a rotating magnetic field,

a plurality of second magnetic elements provided in correspondence with said plurality of coils respectively and each inserted in the corresponding coil,

each said second magnetic element is shorter than the corresponding coil in a direction of a central axis of said impeller,

a first groove for hydrodynamic bearing is formed in one surface of said impeller or in an inner wall of said first chamber facing the one surface, and a second groove for hydrodynamic bearing is formed in an other surface of said impeller or in said dividing wall facing the other surface,

during rotation of said impeller, a force which is the sum of a first hydrodynamic force during rated rotation generated by said first groove for hydrodynamic bearing and an attractive force between said plurality of first magnetic elements and said plurality of second magnetic elements, and a second hydrodynamic force during rated rotation generated by said second groove for hydrodynamic bearing are balanced with each other substantially in a center of a movable range of said impeller in said first chamber, and

each said second magnetic element includes a strip-shaped magnetic steel plate wound a plurality of times around a center line.

9. The centrifugal pump apparatus according to claim 8, wherein

said drive unit further includes a disc-shaped third magnetic element,

said plurality of coils are provided between said dividing wall and said third magnetic element, and

said plurality of second magnetic elements are joined to said third magnetic element.

10. The centrifugal pump apparatus according to claim 8, wherein

a third groove for hydrodynamic bearing is formed in an outer circumferential surface of said impeller or in an inner circumferential surface of said first chamber facing the outer circumferential surface.

11. The centrifugal pump apparatus according to claim 8, wherein said fluid is blood, and said centrifugal pump apparatus is used for circulating said blood.

12. A centrifugal pump apparatus including a housing having first and second dividing walls and a fluid chamber therebetween, an impeller rotatably provided in said fluid chamber along said first and second dividing walls, for delivering fluid by centrifugal force during rotation, and first and second drive units provided outside said fluid chamber, for driving said impeller to rotate, respectively, comprising

a plurality of first magnetic elements provided in said impeller, arranged in a direction of rotation of said impeller, and attracted by said first and second drive units, wherein

each of said first and second drive units includes

a plurality of coils provided to face said plurality of first magnetic elements, for generating a rotating magnetic field,

a plurality of second magnetic elements provided in correspondence with said plurality of coils respectively and each inserted in the corresponding coil,

each said second magnetic element is shorter than the corresponding coil in a direction of a central axis of said impeller,

during rotation of said impeller, a first attractive force between said plurality of first magnetic elements and said plurality of second magnetic elements of said first drive unit and a second attractive force between said plurality of first magnetic elements and said plurality of second magnetic elements of said second drive unit are balanced with each other substantially in a center of a movable range of said impeller in said fluid chamber,

a first groove for hydrodynamic bearing is formed in one surface of said impeller or in said first dividing wall facing the one surface, and a second groove for hydrodynamic bearing is formed in an other surface of said impeller or in said second dividing wall facing the other surface, and

each said second magnetic element includes a strip-shaped magnetic steel plate wound a plurality of times around a center line.

13. The centrifugal pump apparatus according to claim 12, wherein

each of said first and second drive units further includes a disc-shaped third magnetic element,

said plurality of coils of said first drive unit are provided between said first dividing wall and said third magnetic element of said first drive unit,

said plurality of coils of said second drive unit are provided between said second dividing wall and said third magnetic element of said second drive unit, and

in each of said first and second drive units, said plurality of second magnetic elements are joined to said third magnetic element.

14. The centrifugal pump apparatus according to claim 12, wherein

a third groove for hydrodynamic bearing is formed in an outer circumferential surface of said impeller or in an inner circumferential surface of said fluid chamber facing the outer circumferential surface.

15. The centrifugal pump apparatus according to claim 12, wherein said fluid is blood, and said centrifugal pump apparatus is used for circulating said blood.