Blood pump

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.