Blood pump

1 . An intravascular blood pump for percutaneous insertion into a patient's blood vessel, comprising:

a pump casing having a blood flow inlet and a blood flow outlet,

an impeller arranged in said pump casing so as to be rotatable about an axis of rotation, the impeller having blades sized and shaped for conveying blood from the blood flow inlet to the blood flow outlet,

a drive unit for rotating the impeller, the drive unit comprising a first end, a second end, and a magnetic core, the magnetic core including a plurality of posts and a back plate, the plurality of posts connected to the back plate, the plurality of posts arranged about the axis of rotation, each of the plurality of posts including a first end and a second end, wherein the back plate is positioned at or near the first end of the drive unit and is connected to the first end of each of the plurality of posts such that each of the plurality of posts extends away from the back plate toward the second end of the drive unit, wherein the back plate further comprises an intermediate area extending between each of the first ends of the plurality of posts, and

a plurality of coil windings, each coil winding disposed around a respective one of the plurality of posts, the plurality of coil windings being controllable to create a rotating magnetic field,

wherein the impeller comprises a magnetic structure arranged to interact with the rotating magnetic field to cause rotation of the impeller,

wherein the plurality of posts and the back plate are defined by a plurality of laminated sheets of soft magnetic material, and at least a portion of at least one sheet of the plurality of laminated sheets extends continuously from within at least one post of the plurality of posts into the back plate and through at least a portion of the intermediate area of the back plate.

2 . The intravascular blood pump of claim 1 , wherein the plurality of laminated sheets of soft magnetic material form a material that is discontinuous regarding electric conductivity in a cross-section transverse to the axis of rotation.

3 . The intravascular blood pump of claim 2 , further comprising at least one weld bridging a discontinuity regarding electric conductivity in the material formed by the plurality of laminated sheets of soft magnetic material.

4 . The intravascular blood pump of claim 3 , wherein at least one of the at least one weld is arranged on a surface of the back plate opposite to the posts.

5 . The intravascular blood pump of claim 3 , wherein at least one of the at least one weld is arranged on an end surface of a post opposite to the back plate.

6 . The intravascular blood pump of claim 1 , wherein the plurality of laminated sheets of soft magnetic material are each oriented parallel to each other.

7 . The intravascular blood pump of claim 6 , wherein the plurality of laminated sheets of soft magnetic material are each oriented parallel to the axis of rotation.

8 . The intravascular blood pump of claim 1 , wherein the intermediate area of the back plate traverses the axis of rotation.

9 . The intravascular blood pump of claim 1 , wherein the drive unit and the magnetic structure are disposed in non-overlapping positions with respect to each other along the axis of rotation and the plurality of posts are disposed between the magnetic structure and the back plate.

10 . A method of manufacturing a magnetic core for a drive unit of an intravascular blood pump, the magnetic core having an axis of rotation and including a plurality of posts arranged about the axis of rotation and a back plate connecting the plurality of posts, wherein the back plate comprises an intermediate area extending between the plurality of posts, the method comprising the steps of:

providing a monoblock of magnetically conductive material, wherein the monoblock comprises a plurality of laminated sheets of soft magnetic material; and

cutting slots into the monoblock to create the plurality of posts and the back plate such that the plurality of posts are arranged about the axis of rotation and the back plate forms one integral piece with the plurality of posts, wherein at least a portion of at least one sheet of the plurality of laminated sheets extends continuously from within at least one post of the plurality of posts into the back plate and through at least a portion of the intermediate area of the back plate.

11 . The method of claim 10 , wherein the slots are cut using electric discharge machining.

12 . The method of claim 11 , wherein the slots are cut using wire cutting by electric discharge machining.

13 . The method of claim 10 , wherein at least one of the slots is cut through the axis of rotation.

14 . The method of claim 10 , wherein the slots are cut so that the plurality of posts all have an identical length.

15 . The method of claim 10 , wherein the slots are cut such that the back plate has a thickness which is smaller than a maximum cross-sectional dimension of each of the plurality of posts transverse to a longitudinal axis thereof.

16 . The method of claim 10 , wherein the slots are cut using electrochemical machining.

17 . A method of manufacturing an intravascular blood pump having a drive unit with a magnetic core, wherein the magnetic core is manufactured according to claim 10 .