Rotary machine with an electromagnetic rotary drive

• US 6,100,618 A
• Filed: 10/01/1997
• Issued: 08/08/2000
• Est. Priority Date: 04/03/1995
• Status: Expired due to Term

• Current Assignee: Thoratec LLC
• Original Assignee: Lust Antriebstechnik GmbH (KLH Beteiligungs GmbH), Sulzer Electronics AG (Sulzer AG)
• Inventors: Hugel, Joerg, Mendler, Niklaus, Schoeb, Reto
• Primary Examiner(s): Ramirez, Nestor
• Assistant Examiner(s): Lam, Thanh
• Application Number:
  US08/930,649
• Time in Patent Office: 1,042 Days
• Field of Search: 310/90.5, 310/90, 310/198, 310/179, 310/184, 417/356, 623/3
• US Class Current: 310/90.5
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 60/117 for assisting the heart, e.g. transcutaneous or external ventricular assist devices
• CPC Class Codes: A61M 60/122 Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body
• 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 60/422 the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps
• CPC Class Codes: A61M 60/538 Regulation using real-time blood pump operational parameter data, e.g. motor current
• CPC Class Codes: A61M 60/554 of blood pressure
• CPC Class Codes: A61M 60/816 Sensors arranged on or in the housing, e.g. ultrasound flow sensors
• CPC Class Codes: A61M 60/822 specially adapted for being actively controlled
• CPC Class Codes: F04D 1/006 double suction pumps
• CPC Class Codes: F04D 13/0646 the hollow pump or motor shaft being the conduit for the working fluid
• CPC Class Codes: F04D 29/041 Axial thrust balancing
• CPC Class Codes: F04D 29/048 magnetic; electromagnetic
• CPC Class Codes: F04D 29/426 especially adapted for liquid pumps
• CPC Class Codes: F04D 5/001 Shear force pumps
• CPC Class Codes: F05B 2240/511 with permanent magnets
• CPC Class Codes: F05B 2240/515 electromagnetic
• CPC Class Codes: F16C 2316/18 Pumps for pumping blood
• CPC Class Codes: F16C 2360/44 Centrifugal pumps in general F04D
• CPC Class Codes: F16C 32/0446 : Determination of the actual position of the moving member, e.g. details of sensors
• CPC Class Codes: F16C 32/0493 : integrated in an electrodynamic machine, e.g. self-bearing motor
• CPC Class Codes: H02K 7/09 : with magnetic bearings

Abstract

The rotary machine comprises a driven rotor and an electric motor having a stator and a driving rotor. The stator is also executed as an electromagnetic bearing for the driving rotor, and the driving rotor of the electric motor together with the driven rotor of the rotary machine forms a rotor unit, i.e. the two rotors form an integral rotor. The rotary machine can for example be a rotary pump, a centrifugal pump, a centrifuge or a stirring apparatus. The rotor can be constructed so as to be easily removable from the stator.

Claims

1. A rotary machine comprising a driven rotor and an electric motor that includes only a single stator and a driving rotor;

wherein the stator is also executed as an electromagnetic bearing for the driving motor and includes a portion that effects magnetic suspension of the rotor and effects driving of the rotor;

wherein the driving rotor of the electric motor together with the driven rotor of the rotary machine forms a rotary unit.

2. A rotary machine in accordance with claim 1 in which the driving part of the rotor unit is designed to be one of disc-shaped, ring-shaped, or bell-shaped;

and in that the rotor is passively stabilized by reluctance forces both axially as well as against tilting with respect to plane of the stator.

3. A rotary machine in accordance with claim 1 in which the stator together with the driving rotor forms an external rotor motor.

4. A rotary machine in accordance with claim 1 in which the rotor unit is constructed together with a part of the rotor machine as a unit which can be lifted off from the drive stator.

5. A rotary machine in accordance with claim 1 in which the drive stator is built up of individual, rod-shaped coils arranged radially about the rotor with a common magnetic yoke and each coil has partial windings for each winding string of the drive winding and of the control winding.

6. A rotary machine in accordance with claim 1 in which the drive stator is executed, with respect to the rotor in the axial direction, of coils arranged in the manner of the pillars of a temple as a temple motor having a common magnetic yoke, with the flux at one coil end, at the side lying opposite the magnetic yoke, being conducted radially to the rotor through an L-shaped extension of the coil core pointing towards the rotor, and with the coils having partial windings for each winding string of the drive winding and the control winding, where individual partial windings can have 0 as the number of turns and the at least approximately sinusoidal geometrical distribution of the drive flux and the control flux is formed by the winding turn ratio between the individual partial coils.

7. A rotary machine in accordance with claim 1 in which eddy current distance sensors are arranged in individual grooves or between individual coil cores of the drive stator and measure the distance to a conducting layer in the driving rotor in a rotor plane.

8. A rotary machine in accordance with claim 1 in which two oppositely disposed distance sensors are used in the X direction and the Y direction in each case and the components of the position of the driving rotor in a rotor plane are determined from the difference of the sensor signals of oppositely disposed sensors.

9. A rotary machine in accordance with claim 1 in which sensor windings are arranged in the drive stator in addition to the drive and control windings.

10. A rotary machine in accordance with claim 1 in which an axial position of the rotor is regulated and stabilized through the application of a magnetization current in the drive winding or by means of an additional axial coil at the one side of the rotor.

11. A rotary machine in accordance with claim 1 in which a split tube is arranged between the drive stator and the integral rotor.

12. A rotary machine in accordance with claim 1, executed as a rotary pump, with a closed pump housing which contains an rotor unit which encloses the driving rotor of the motor and the driven rotor of the pump.

13. A rotary machine in accordance with claim 1, executed as a rotary pump, with a pump housing that is arranged on the drive stator in such a manner as to be freely accessible and replaceable from at least one side.

14. A rotary machine in accordance with claim 1, executed as an axial pump, with a ring-shaped driving rotor which surrounds the vaned wheel of the axial pump in a ring-like manner.

15. A rotary machine executed as an axial pump in accordance with claim 1, the pump housing of which has an inlet stub at the one side and an outlet stub at the other side via which stubs the pump is inserted into the forwarding circuit in such a manner that the pump housing can be removed with the pump wheel from the driving stator after removal of the preferably hose-like connections.

16. A rotary machine in accordance with claim 1, executed as a centrifugal pump, whose ring-shaped or disc-shaped driving rotor is integrated into a vaned wheel or is mounted onto the vaned wheel.

17. A rotary machine in accordance with claim 1, executed as a rotary pump, in which the axial rotor position signal or the control signal of the control system which is required for the axial stabilization of the rotor is used for the determination of the pump pressure.

18. A rotary machine, executed as a rotary pump, in accordance with claim 1 with means for determining the through-flow of a fluid through the pump from the axial rotor position signal from the speed of rotation of the rotor and from the driving current.

19. A rotary machine in accordance with claim 1 in which the axial length of the driving rotor is smaller than or equal to half the diameter of this rotor.

20. A rotary machine in accordance with claim 1 wherein means are present in the stator which produce a unipolar flux in the electric motor;

and wherein the stator has a bipolar rotary field winding via which radial magnetic fields acting on the rotor can be controlled; and

wherein the stator has a further rotary field winding with a number of pole pairs p, p≧

2, via which a rotary field can be produced for driving the rotor.

21. A rotary machine in accordance with claim 20 wherein the unipolar flux in the electric motor is produced by permanent magnets.

22. A rotary machine in accordance with claim 1 comprising

a rotary winding with a number of pole pairs p for the production of a rotary driving field and for the controlled rotation of the driving rotor about its axis of rotation, and

a control winding with a number of pole pairs p+1 or p-1 for the production of a control field superimposed on the rotary driving field in order to regulate a radial position of the driven rotor in its plane of rotation in a controlled manner.

23. A rotary machine in accordance with claim 22 in which a number of turns of the partial windings is chosen in such a manner that a drive flux and a control flux are geometrically at least approximately sinusoidal.

24. A rotary machine in accordance with claim 23 with a two phase winding in which the number of turns of each partial winding of the first phase is a given number of turns N₁ or N₁, respectively, times the cosine of the electric angle alpha of its position ([N₁ x cos (p alpha)] for the drive winding and [N₁ x cos {(p±

1 alpha}] for the control winding) and the number of turns of each partial winding of the second phase is a given number of turns N₁ and N₂, respectively, times the sine of the electric angle alpha of its position ([N₂ x sin (p alpha)] for the drive winding and [N₂ x sin {(p±

1 alpha}] for th conrol winding) or vice versa.

25. A replaceable unit comprising:

a housing having an inlet for a fluid to be forwarded from the inlet through the housing to the outlet; and

a driving rotor and a driven rotor arranged within the housing, the driving rotor and thge driven rotor forming an integral rotor, which is adapted to be magnetically suspended and driven by the poles of only a single stator and includes a portion that effects magnetic syspension of the rotor and effects driving of the rotor, the integral rotor having means thereon for forwarding the fluid the inlet to the outlet upon rotation of the integral rotor.

26. A replaceable unit in accordance with claim 25, wherein the housing is made from plastics and forms a disposable unit with the integral rotor.

27. A replaceable unit in accordance with claim 26, wherein the integral rotor has a ring-shaped rotor disc in which electromagnetically active components of the integral rotor are accommodated and to which rotor blades are fastened.

28. A replaceable unit in accordance with claim 27, wherein the electromagnetically active components of the integral rotor comprise permanent magnets as well as iron.

29. A replaceable unit in accordance with claim 25, wherein the integral rotor has a ring-shaped rotor disc in which electromagnetically active components of the integral rotor are accommodated and to which rotor blades are fastened.