Blood pump with micromotor

Patent metadata

Field	Value
Publication number	US-10808704-B2
Application number	US-53281608-A
Country	US
Kind code	B2
Filing date	Mar 14, 2008
Priority date	Mar 24, 2007
Publication date	Oct 20, 2020
Grant date	Oct 20, 2020

Abstract

The invention relates to a micromotor (10), the stator of which contains a back iron jacket (18). Said back iron jacket consists of a continuous unslotted sleeve consisting of a metal alloy that contains ferritic iron as the main constituent, up to 30% chromium and preferably aluminium and yttrium oxide. Electric conductivity is reduced by the oxidation of the aluminium. The yttrium oxide performs the same function. The reduced electric conductivity suppresses eddy currents to a great extent. The back iron jacket (18) has a high magnetic conductivity with a small wall thickness, thus increasing the electrical output for a motor with a small diameter.

First claim

The invention claimed is:

1. A blood pump with micromotor sized for intravascular insertion, provided for intracorporeal use, said blood pump comprising:
a stator comprising:
a first shell;
an exciter coil embedded in the first shell and containing wires for conducting an alternating current; and
a magnetic-reflux jacket made of magnetically conductive material and fully surrounding the first shell, wherein the magnetic reflux jacket includes a one-piece unslotted second shell made of a ferritic alloy containing iron as the main component and up to 30% chromium, that reduces magnetic losses of magnetic reflux and the strength of eddy currents, thereby reducing the motor current for a required drive power of the blood pump compared to a magnetic-reflux jacket having a slotted shell.

2. The blood pump according to claim 1 , wherein the ferritic alloy of the magnetic-reflux jacket contains up 3% to 8% aluminum.

3. The blood pump according to claim 1 , wherein the ferritic alloy of the magnetic-reflux jacket contains up 0.3% to 2% yttrium oxide.

4. The blood pump according to claim 1 , wherein the ferritic alloy of the magnetic-reflux jacket contains maximally 0.2% copper.

5. The blood pump according to claim 1 , wherein the ferritic alloy of the magnetic-reflux jacket contains, apart from iron, the following components:

chromium
18.50%-21.50%

aluminum
3.75%-5.75%

titanium
0.20%-0.60%

carbon
0.10% maximum

yttrium oxide
0.30%-0.70%

copper
0.15% maximum

manganese
0.30% maximum

cobalt
0.30% maximum

nickel
0.50% maximum

phosphorus
 0.02% maximum.

6. The blood pump according to claim 1 , wherein the outer diameter of the magnetic-reflux jacket does not exceed 4.6 mm and the inner diameter is at least 3.3 mm.

7. The blood pump according to claim 1 , wherein windows are provided on the proximal end of the magnetic-reflux jacket.

8. The blood pump according to claim 1 , wherein the magnetic-reflux jacket is connected to a housing of the blood pump by a welding seam.

9. The blood pump according to claim 1 , wherein the magnetic-reflux jacket is configured to reduce strength of eddy currents therein.

10. The blood pump according to claim 1 , wherein the second shell is configured to reduce magnetic losses in the micromotor.

11. The blood pump according to claim 1 , wherein the magnetic-reflux jacket comprises a constant wall thickness.

12. The blood pump according to claim 1 , wherein the magnetic-reflux jacket is covered by a plastic layer.

13. The blood pump according to claim 1 , further comprising a pump portion axially following the micromotor, wherein the pump portion comprises an impeller fastened to a shaft, and wherein the impeller is arranged for rotation within a pump housing.

Assignees

• Siess Thorsten
• Kirchhoff Frank
• Abiomed Europe Gmbh

Inventors

• Siess Thorsten
• Kirchhoff Frank

Classifications

• A61M60/825

  Contact bearings, e.g. ball-and-cup or pivot bearings · CPC title

• A61M60/237

  the blood flow through the rotating member having mainly axial components, e.g. axial flow pumps · CPC title

• A61M60/422

  the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps · CPC title

• A61M60/577

  High-frequency driving · CPC title

• A61M60/211

  using a jet, venturi or entrainment effect for pumping the blood · CPC title