Blood pump and method for manufacturing magnetic core for blood pump drive unit

Abstract

The present invention relates to a blood pump (1) that is percutaneously inserted into a patient's blood vessel, and includes a pump casing (2) having a blood inlet (21) and a blood outlet (22), a pump element (3) disposed within the pump casing (2) so as to be rotatable about a rotation axis (10) and to transport blood from the blood inlet (21) to the blood outlet (22), and a drive unit (4) that rotates the pump element (3). The drive unit (4) includes a magnetic core (400) having a plurality of posts (40) arranged around the rotation axis (10) and a back plate (50) connecting the posts (40), and a coil. and a coil winding (44) disposed about each post (40), the coil windings (44) being controllable to generate a rotating magnetic field, the pump elements (3) including a magnetic structure (32) arranged to interact with the rotating magnetic field to cause rotation of the pump elements (3), the magnetic core (400) comprising or consisting of at least one layered sheet (85) of soft magnetic material extending at least partially circumferentially within each post (40) about the axis of rotation (10). The present invention further relates to a method of manufacturing the magnetic core (400) for a blood pump (1).

Description

[Technical Field]

[0001] The present invention relates to a blood pump, and more particularly to an intravascular blood pump that is percutaneously inserted into a patient's blood vessel to support blood flow within the patient's vessel. The blood pump has an improved drive unit. The present invention also relates to a method for manufacturing a magnetic core for a blood pump drive unit. The magnetic core may be a soft magnetic core. [Background technology]

[0002] Various types of blood pumps are known, including axial-flow blood pumps, centrifugal (i.e., radial) blood pumps, and mixed-flow blood pumps in which blood flow is induced by both axial and radial forces. Intravascular blood pumps are inserted into a patient's blood vessels, such as the aorta, by a catheter. Blood pumps typically include a pump casing having a blood inlet and a blood outlet connected by a passageway. An impeller or rotor is rotatably supported within the pump casing and has blood-carrying blades (teeth) attached to it to generate blood flow along the passageway from the blood inlet to the blood outlet.

[0003] Blood pumps are typically driven by a drive unit, e.g., an electric motor. For example, Patent Document 1 discloses an extracorporeal blood pump having an impeller that can be magnetically coupled to the electric motor. The impeller is equipped with magnets, which are arranged adjacent to magnets in the electric motor. Rotation of the motor is transmitted to the impeller by the attractive force between the magnets in the impeller and the motor. To reduce the number of rotating parts, a rotating magnetic field is utilized, as also known from Patent Document 1. The drive unit has multiple stationary posts arranged around the axis of rotation, each of which carries a wire coil winding and acts as a magnetic core. A rotating magnetic field can be generated by sequentially applying voltage to the coil windings from a control unit. To achieve a sufficiently strong magnetic coupling, the magnetic force must be sufficiently strong. This can be achieved by supplying a sufficiently large current to the drive unit or by using a large magnet, but this increases the overall diameter of the blood pump. Patent Document 2 discloses a blood pump, particularly an intravascular blood pump, with magnetic coupling between the drive unit and the impeller. The blood pump design is compact, particularly because the pump has a high pumping power to size ratio, allowing the overall dimensions to be small enough to make the blood pump transvascularly, transvenously, transarterially or transvalvularly insertable, or even smaller for handling and convenience reasons.

[0004] More specifically, the blood pump in Patent Document 2 includes a pump casing having a blood inlet and a blood outlet, an impeller, and a drive unit for rotating the impeller. Rotating the impeller around a rotation axis within the pump casing causes the impeller blades to transport blood from the blood inlet to the blood outlet. The drive unit includes a magnetic core having a plurality of posts, preferably six, and a backplate that connects the rear ends of the posts and serves as a yoke. The posts are arranged in a circle around the rotation axis when viewed along a plane perpendicular to the rotation axis, and each post has a long axis that is preferably parallel to the rotation axis. The backplate has through-holes into which the rear ends of the posts are form-fitted, with the end faces of the rear ends of each post being flush with the rear surface of the backplate. Thus, a magnetic connection between the posts and the backplate is generated between the peripheries of the posts and the inner contour of the opening in the backplate. Each post has a coil winding disposed therearound that is coherently controlled to generate a rotating magnetic field that drives the impeller. The impeller has a magnetic structure in the form of magnets that are arranged to interact with the rotating magnetic field and cause the impeller to follow its rotation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2011 / 0238172 (A1) [Patent Document 2] European Patent No. 3222301 (B1) Summary of the Invention [Problem to be solved by the invention]

[0006] It is an object of the present invention to provide a blood pump having an improved drive unit, thereby improving the magnetic flux in the magnetic core. It is a further object of the present invention to provide a method for manufacturing the magnetic core of the corresponding drive unit. [Means for solving the problem]

[0007] The blood pump of the present disclosure can correspond to the blood pumps described above, and thus can be an axial flow blood pump, or a mixed flow blood pump that pumps partly axially and partly radially (the diameter of a purely centrifugal blood pump is usually too large for intravascular applications).

[0008] According to a first aspect, a blood pump for percutaneous insertion into a patient's blood vessel includes a pump casing and a drive unit. The pump casing has a blood inlet and a blood outlet, and a pump element is disposed within the pump casing. The pump element may be an impeller, rotatable about a rotation axis to transport blood from the blood inlet to the blood outlet. The drive unit is configured to rotate the pump element. The drive unit includes a magnetic core having a plurality of posts arranged about the rotation axis and a backplate connecting the posts. The drive unit further includes a coil winding disposed around each post. The coil winding is controllable to generate a rotating magnetic field, and the pump element includes a magnetic structure arranged to interact with the rotating magnetic field to cause rotation of the pump element. The magnetic core may include or consist of at least one layered sheet of soft magnetic material. The at least one sheet may extend at least partially circumferentially within each post about the rotation axis. In other words, when viewed along a cross section perpendicular to the axis of rotation, the at least one sheet may be curved, and in particular may have a shape resembling a circular arc.

[0009] Preferably, at least a portion of the material of at least one of the posts of the magnetic core is integral with the material of the backplate of the magnetic core. Preferably, all posts are integrally connected to the backplate in this manner. In other words, at least one post and the backplate, and preferably the entire magnetic core, can be made from a single block of material, also referred to hereinafter as a monoblock. One advantage of such a magnetic core is that the magnetic reluctance at the post-backplate transition is minimized, thereby improving magnetic flux. Furthermore, a post-backplate transition with good mechanical rigidity can be achieved. The backplate may also have an intermediate area, i.e., an area that constitutes the backplate and is located between the posts.

[0010] The longitudinal axis of each post may be parallel to the axis of rotation. Preferably, the magnetic core comprises a discontinuous soft magnetic material. More preferably, the soft magnetic material of the magnetic core is discontinuous along a cross section transverse to, preferably perpendicular to, the longitudinal axis of the posts. In other words, the soft magnetic material of the posts is discontinuous along a cross section transverse to, preferably perpendicular to, the direction of magnetic flux induced by the individual coil windings in the post. By dividing or segmenting the soft magnetic material along the cross section, eddy currents within the posts can be reduced or avoided, thereby reducing heat generation and energy consumption. Reduced energy consumption is particularly useful for long-term use of blood pumps. In such applications, it is desirable to power the blood pump with a battery to provide mobility to the patient. Furthermore, the blood pump can be operated without purging during long-term use, which is only possible with low heat generation.

[0011] For purposes of this document, "discontinuous" means that, when viewed along any cross section, for example, transverse to the longitudinal axis or axis of rotation of the post, the soft magnetic material is divided, separated, or intersected by insulating or other material or gaps, forming distinctly separate areas of soft magnetic material or areas that are separated but connected at different locations. Providing discontinuous soft magnetic material in a cross section transverse to the direction of magnetic flux reduces eddy currents, and thus heat generation and energy consumption, as explained above. To avoid a significant weakening of the magnetic field compared to a continuous or full-bodied (i.e., solid) soft magnetic material, the continuous area of ​​the soft magnetic material can be reduced while the total amount of the soft magnetic material is increased. This can be achieved, for example, by providing the soft magnetic material in the form of multiple sheets of soft magnetic material, for example, made of electrical steel. Specifically, the sheets can be layered, e.g., laminated, to form a stack of sheets. Preferably, the sheets are electrically insulated from one another, for example, by providing an adhesive, lacquer, baked enamel, or the like between adjacent sheets. Such an arrangement can be referred to as "slot-interposed." Compared to full-body soft magnetic materials, the amount of soft magnetic material is reduced only slightly, and the amount of insulating material is kept small, so the magnetic field generated by slot-interposed posts is substantially the same as that generated by solid posts. In other words, heat generation and energy consumption are significantly reduced, while the magnetic field depletion caused by the insulating material is insignificant.

[0012] Preferably, the magnetic core includes a first support member. The first support member may include a first tubular portion and a plurality of first fingers extending from the first tubular portion. The first tubular portion may form the inner circumferential surface of the backplate. Each of the plurality of first fingers may form the inner circumferential surface of one of the plurality of posts. In other words, the innermost layer of the magnetic core (i.e., the layer closest to the rotation axis) may be formed by the first support member.

[0013] The magnetic core may include a second support member. The second support member may include a second tubular portion and a plurality of second fingers extending from the second tubular portion. The second tubular portion may form the outer circumferential surface of the backplate. Each of the second fingers may form the outer circumferential surface of one of the posts. In other words, the second support member may form the outermost layer of the magnetic core (i.e., the layer farthest from the axis of rotation). Preferably, the at least one sheet extends parallel to the longitudinal axis of each post. In other words, the sheet may extend substantially parallel to the direction of magnetic flux so that the posts are discontinuous along a cross section transverse or perpendicular to the magnetic flux direction. As can be appreciated, the at least one sheet may extend at an angle to the longitudinal axis of each post, as long as the soft magnetic material is discontinuous along a cross section transverse to the longitudinal axis. Preferably, the thickness of the at least one sheet is set to 25 μm to 1 mm, more preferably 50 μm to about 450 μm, for example, in the range of 50 μm to 200 μm.

[0014] The first support member may have a thickness greater than the thickness of the at least one sheet. Additionally, the second support member may have a thickness greater than the thickness of the at least one sheet. It may be advantageous to provide a large, continuous area of ​​soft magnetic material at the center of the post when viewed in cross section across its longitudinal axis, because this enhances the magnetic flux passing through the center of each post along its longitudinal axis and because eddy currents in the center or radially outward areas are less significant than eddy currents at the sides of the post.

[0015] Preferably, an area of ​​material, such as a sheet of soft magnetic material, may extend into both the posts and the backplate. Although the material may be discontinuous, the magnetic core may be made of a single block of such material. Such an area of ​​material is continuous from the posts through the intermediate areas of the backplate and between the posts, rather than being interrupted by the post-to-backplate transitions.

[0016] It is generally known that eddy currents can be avoided or reduced by incorporating slotted soft magnetic materials, such as electrical steel, into electric motors. However, this technology has been applied to large devices, where the sheets typically have thicknesses in the range of approximately 500 μm or greater. In smaller applications, such as the blood pump disclosed herein, where a single post typically has a diameter of the aforementioned magnitude and the power input is relatively low (e.g., up to 20 watts (W)), eddy currents and the associated problems were not anticipated. Surprisingly, despite the small post diameter, eddy currents, and therefore heat generation and energy consumption, can be reduced by incorporating slotted posts. This is advantageous for the operation of blood pumps, which can operate at high speeds, sometimes reaching 50,000 rpm (revolutions per minute).

[0017] As can be appreciated, the discontinuous soft magnetic material may be disposed within the posts in arrangements other than the slotted arrangement described above. For example, an insulating layer may be automatically formed by an oxide layer resulting from oxidation of the soft magnetic material due to exposure to air, thereby eliminating the need for additional insulating material. Non-uniform arrangements may also be provided while the sheets or other structures of soft magnetic material are uniformly formed, i.e., the sheets within one or all of the posts are the same thickness. For example, the sheets may have different thicknesses. More specifically, in a stack of sheets, one or more central sheets may be of a larger thickness, while adjacent sheets toward the edges of the stack may be of a smaller thickness. That is, the thickness of the sheets may decrease from the center toward the edges of the stack, i.e., toward the outermost sheets of the stack.

[0018] The diameter of the backplate can be 3 mm to 9 mm, for example, in the range of 5 mm or 6 mm to 7 mm. The thickness of the backplate can be 0.5 mm to 2.5 mm, for example, 1.5 mm. The outer diameter of the blood pump can be 4 mm to 10 mm, preferably 7 mm. The outer diameter of the array of multiple posts can be 3 mm to 8 mm, for example, in the range of 4 mm to 7.5 mm, preferably 6.5 mm.

[0019] As previously mentioned, the posts are made of a soft magnetic material, such as electrical steel (magnetic steel). The posts and backplate may be made of the same material. Preferably, the drive unit, including the posts and backplate, is made of cobalt steel. Preferably, at least one of the aforementioned sheets and / or the posts and / or backplate is made of Vacoflux® 48, Vacoflux® 50, Vacodur® 49, or Vacodur® 50.

[0020] The first and / or second support members may be made of Vacoflux® 48, Vacoflux® 50, Vacodur® 49, or Vacodur® 50. The use of cobalt steel contributes to reducing the pump size, particularly the diameter. Cobalt steel has the highest permeability and highest saturation flux density of all magnetic steels, providing the most magnetic flux for the same amount of material used.

[0021] Preferably, the magnetic core comprises or is made up of a plurality of layered sheets, which are stacked or laminated axially and / or radially.

[0022] The dimensions of the post, particularly its length and cross-sectional area, can vary and depend on a variety of factors. In contrast to the dimensions of a blood pump, such as its outer diameter, which depend on the application of the blood pump, the dimensions of the post are determined by its electromagnetic properties, which can be adjusted to achieve desired drive unit characteristics. One such factor is the magnetic flux density achieved at the smallest cross-sectional area of ​​the post. The smaller the cross-sectional area, the more current is required to achieve the desired magnetic flux. However, the higher the current, the more heat is generated in the wire of the coil due to electrical resistance. This means that while a "thinner" post is desirable to reduce overall size, it requires a higher current, which is likely to generate undesirable heat. The heat generated in the wire also depends on the length and diameter of the wire used in the coil winding. Shorter wire lengths and larger wire diameters are desirable to reduce winding losses (typically referred to as "copper losses" or "copper power losses" when copper wire is used). In other words, a smaller wire diameter generates more heat for the same current than a larger wire diameter, so a preferred wire diameter is, for example, 0.05 mm to 0.2 mm, e.g., 0.1 mm. Additional factors affecting post size and drive unit performance include the number of coil turns and the outer diameter of the turns, i.e., the outer diameter of the post including the windings. Multiple windings may be arranged in multiple layers around each post, e.g., two or three layers. However, the more layers, the more heat generated. This is because the outer layers, which have larger winding diameters, have longer wire lengths. Longer wire lengths can generate more heat because longer wire has higher resistance compared to shorter wire. Therefore, a single layer winding with a smaller winding diameter may be desirable. A typical number of turns, depending on the length of the post, may be about 50 to about 150, e.g., 56 or 132 turns. Regardless of the number of turns, the coil winding is made of a conductive material, particularly a metal, e.g., copper or silver. Silver may be preferable to copper because the electrical resistivity of silver is about 5% lower than that of copper. Preferably, the magnetic core is provided with one or more welds.The welds can be located on the outer surface of the magnetic core, i.e., in locations that are particularly accessible for laser welding, etc. The welds can bridge electrical conductivity discontinuities in the soft magnetic material, i.e., electrically connect at least two sheets of soft magnetic material. The welds can also add mechanical stability to the discontinuous soft magnetic material.

[0023] The one or more welds are located on the surface of the magnetic core to bridge electrical conductivity discontinuities in the soft magnetic material. Therefore, at least one weld may be located on the surface of the backplate opposite the post. Furthermore, at least one weld may be located on the end face of the post opposite the backplate. The at least one weld may be created by laser welding. When using a laminated sheet material, the welds preferably bridge adjacent soft magnetic sheets diagonally or transversely.

[0024] According to a second aspect of the present disclosure, a method for manufacturing a magnetic core for a drive unit of a blood pump is proposed. The magnetic core has a rotation axis, a plurality of posts arranged about the rotation axis, and a backplate connecting the posts. The method includes the steps of preparing a monoblock and cutting slots into the monoblock to produce the posts and to produce a backplate that forms an integral piece with the posts. As previously pointed out, one advantage of this manufacturing method is that the resulting magnetic core has reduced reluctance.

[0025] Preferably, the monoblock comprises or consists of at least one layered sheet of soft magnetic material, which may extend at least partially circumferentially around the axis of rotation.

[0026] At least one slot, and preferably all opposing slots on either side of the rotation axis, can be made by cutting through the rotation axis of the magnetic core, which makes it easier to achieve a uniform distribution of the posts around the rotation axis.

[0027] Preferably, the slots are cut so that all of the posts have the same length. In particular, the slots are cut so that the thickness of the backplate is less than the maximum cross-sectional dimension of the posts transverse to their longitudinal axes. The slots are preferably cut using electrical discharge machining, particularly wire electrical discharge machining, or electrochemical machining. These methods are particularly advantageous for machining discontinuous materials because they apply minimal force to the material being machined.

[0028] If the post comprises or is composed of layered sheets of magnetic material, e.g., laminated sheets, there is a risk that the sheets in the post adjacent to the slot will become too thin and thus completely burn away due to the heat generated by the EDM process. In the resulting motor, the motor parameters of the three motor phases may be biased due to uneven burn-away of the post material. Therefore, it is preferable to prepare a monoblock by winding at least one layered sheet around the axis of rotation. This reduces or completely eliminates the risk of the sheet becoming too thin. A side benefit is that because the orientation of the sheets within the post is the same for all posts, the EDM process affects all posts in substantially the same way, and therefore all three motor phases in the resulting motor are affected in the same way.

[0029] Preferably, the sheet is wrapped around a first support member, which is preferably a single-piece tubular member, and preferably, the sheet is secured to the first support member prior to wrapping, particularly by welding or gluing.

[0030] Preferably, a bonding layer made of a non-conductive material is provided between the layers of the sheet and / or between the sheet and the first support member and / or between the sheet and the second support member. The bonding layer may contain an adhesive, preferably an epoxy adhesive, which significantly increases the stability of the monoblock.

[0031] Prior to cutting the slots, at least one weld may be provided on the outer surface of the monoblock. In particular, the at least one weld may be provided on the outer periphery of the rolled sheet to secure the rolled sheet. In particular, the additional weld may be at least one spot weld to secure the ends of the rolled sheet.

[0032] Preferably, the at least one sheet or monoblock is annealed prior to cutting the slots, and more preferably, the at least one sheet or monoblock is magnetically annealed prior to cutting the slots, to ensure that the at least one sheet or monoblock has the desired magnetic properties.

[0033] The monoblock may be at least partially coated after slot cutting. In particular, the outer periphery of the posts and / or backplate may be coated. Additionally, the end faces of the posts may be coated. Preferably, the surface of the backplate facing away from the posts is left uncoated. Preferably, the coating provides electrical insulation and mechanical stability, and does so with a small thickness. The coating may therefore be a DLC (diamond-like carbon), perylene or polyamide coating.

[0034] In a further aspect of the present disclosure, a blood pump is provided having a drive unit with a magnetic core, the magnetic core being manufactured as described above.

[0035] The foregoing summary, as well as the following detailed description of preferred embodiments, will be better understood when read in conjunction with the accompanying drawings. For purposes of illustrating the present disclosure, reference is made to the drawings. However, the scope of the present disclosure is not limited to the specific embodiments disclosed in the drawings. The drawings are as follows: [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 2 is a cross-sectional view showing the external appearance of the blood pump. [Figure 2] FIG. 1 shows a cross-sectional view of a preferred embodiment of a drive unit impeller arrangement. [Figure 3A] 3A to 3C are diagrams illustrating a manufacturing process of the integrated magnetic core for the drive unit according to the first embodiment and shown in FIG. 2. [Figure 3B] 3A to 3C are diagrams illustrating a manufacturing process of the integrated magnetic core for the drive unit according to the first embodiment and shown in FIG. 2. [Figure 3C] 3A to 3C are diagrams illustrating a manufacturing process of the integrated magnetic core for the drive unit according to the first embodiment and shown in FIG. 2. [Figure 4A] 3D is a diagram showing a weld on an integrated magnetic core manufactured according to FIGS. 3A to 3C. FIG. [Figure 4B] 3D is a diagram showing a weld on an integrated magnetic core manufactured according to FIGS. 3A to 3C. FIG. [Figure 4C] 3D is a diagram showing a weld on an integrated magnetic core manufactured according to FIGS. 3A to 3C. FIG. [Figure 5A] FIG. 10 is a diagram showing a cross section of a passage through a post according to an embodiment. [Figure 5B] FIG. 10 is a view showing a cross section of passage through a post according to another embodiment. [Figure 5C] FIG. 10 is a view showing a cross section of passage through a post according to another embodiment. [Figure 5D] FIG. 10 is a view showing a cross section of passage through a post according to another embodiment. [Figure 6A] FIG. 1 is a diagram showing a concentric soft magnetic sheet monoblock before slot cutting. [Figure 6B]FIG. 10 shows a concentric soft magnetic sheet monoblock after slot cutting. [Figure 7A] 10A to 10C are diagrams illustrating a manufacturing process of the integrated magnetic core for a drive unit according to another embodiment of the present invention; [Figure 7B] 3A to 3C are diagrams showing a manufacturing process of the integrated magnetic core for a drive unit shown in FIG. 2 according to the embodiment. [Figure 7C] 3A to 3C are diagrams showing a manufacturing process of the integrated magnetic core for a drive unit shown in FIG. 2 according to the embodiment. [Figure 7D] 3A to 3C are diagrams showing a manufacturing process of the integrated magnetic core for a drive unit shown in FIG. 2 according to the embodiment. [Figure 8A] 10A to 10C are diagrams illustrating a manufacturing process of the integrated magnetic core for a drive unit according to another embodiment of the present invention; [Figure 8B] 3A to 3C are diagrams showing a manufacturing process of the integrated magnetic core for a drive unit shown in FIG. 2 according to the embodiment. [Figure 8C] 3A to 3C are diagrams showing a manufacturing process of the integrated magnetic core for a drive unit shown in FIG. 2 according to the embodiment. [Figure 8D] 3A to 3C are diagrams showing a manufacturing process of the integrated magnetic core for a drive unit shown in FIG. 2 according to the embodiment. [Figure 9] FIG. 10 is a diagram showing a monoblock with a support member before cutting. [Figure 10A] FIG. 10 is a diagram showing a concentric ring-shaped soft magnetic sheet monoblock before slots are cut. [Figure 10B] FIG. 10 is a diagram showing a concentric ring-shaped soft magnetic sheet monoblock after slot cutting. DETAILED DESCRIPTION OF THE INVENTION

[0037] FIG. 1 illustrates a cross-sectional view of blood pump 1. Blood pump 1 includes pump casing 2 with blood inlet 21 and blood outlet 22. Blood pump 1 is designed as an intravascular pump, also known as a catheter pump, and is deployed within a patient's blood vessels via catheter 25. Blood inlet 21 is located at the end of flexible cannula 23, which, in use, can be positioned through a heart valve, e.g., the aortic valve. Blood outlet 22 is located on the side of pump casing 2 and can be placed within a cardiac vessel, e.g., the aorta. Blood pump 1 is electrically conductively connected to electrical conductors 26 extending through catheter 25, which provide electrical power to blood pump 1 for driving drive unit 4, as will be described in more detail below.

[0038] If the blood pump 1 is intended for long-term use, i.e., for weeks or even months while the blood pump 1 is implanted in a patient, it is desirable for the power to be supplied by a battery. This allows the patient to be mobile, as they are not tethered by a cable to a base station. The battery may be carried by the patient and may supply electrical energy to the blood pump 1, for example, wirelessly.

[0039] Blood is conveyed along a passageway 24 connecting a blood inlet 21 and a blood outlet 22 (blood flow indicated by arrows). A pump element 3 in the form of an impeller 3 is provided to convey blood along the passageway 24 and is mounted within the pump casing 2 by first and second bearings 11 and 12 for rotation about a rotation axis 10, which is preferably the longitudinal axis of the impeller 3. In this embodiment, both bearings 11 and 12 are contact bearings. However, at least one of the bearings 11 and 12 could be a non-contact bearing, such as a magnetic or hydrodynamic bearing. The first bearing 11 is a pivot bearing with a spherical seat, allowing some pivoting movement in addition to rotational movement. A pin 15 is provided, forming one of the seats. A second bearing 12 is provided within a retaining member 13 to stabilize the rotation of the impeller 3, and the retaining member 13 has at least one blood flow opening 14. Blades 31 are mounted on an impeller 3, which propels blood as the impeller 3 rotates. A drive unit 4, which causes the impeller 3 to rotate, is magnetically coupled to a magnet 32 ​​at the end of the impeller 3. The depicted blood pump 1 is a mixed-flow blood pump, and its primary flow direction is axial. As can be seen, blood pump 1 could also be a pure axial-flow blood pump, depending on the arrangement of its impeller 3, and in particular the blades 31.

[0040] The blood pump 1 includes an impeller 3 and a drive unit 4. The drive unit 4 includes multiple posts 40, e.g., six posts 40, only two of which are visible in the cross-sectional view of FIG. 1 . The posts 40 are arranged parallel to the rotation axis 10. More specifically, the long axis of each post 40 is parallel to the rotation axis 10. One end of the posts is disposed adjacent to the impeller. Coil windings 44 are disposed around the posts 40. The coil windings 44 can be sequentially controlled by a control unit to generate a rotating magnetic field. A portion of the control unit is a printed circuit board 6 and is connected to the conductive lines 26. The impeller includes a magnet 32, which in this embodiment is formed as a multi-piece magnet. The magnet 32 ​​is disposed at the end of the impeller 3 facing the drive unit 4. The magnet 32 ​​is arranged to interact with the rotating magnetic field and thereby generate rotation of the impeller 3 about the rotation axis 10.

[0041] To close the magnetic flux path, a backplate 50 is disposed on the end of the post 40 opposite the impeller. The post 40 serves as a magnetic core and is made of a suitable material, particularly a soft magnetic material, such as steel or a suitable alloy, especially cobalt steel. Similarly, the backplate 50 is made of a suitable soft magnetic material, such as cobalt steel. The backplate 50 enhances the magnetic flux, allowing the overall diameter of the blood pump 1 to be reduced, which is important for intravascular blood pumps. For the same purpose, a yoke 37, i.e., an additional impeller backplate, is provided on the impeller 3 and is located on the side of the magnet 32 ​​facing away from the drive unit 4. In this embodiment, the yoke 37 is frustoconical to guide blood flow along the impeller 3. The yoke 37 may also be made of cobalt steel. One or more washout channels extending toward the central bearing 11 may be formed in the yoke 37 or magnet 32.

[0042] FIG. 2 shows a cross-sectional view of a preferred embodiment of a drive unit impeller arrangement for the blood pump according to FIG. 1. As can be seen in FIG. 2, the proximal ends 420 of the posts 40 do not extend radially beyond the windings 44. Rather, the cross-section of the posts 40 remains constant along the longitudinal axis LA of the posts 40. This prevents the posts 40 from coming too close together, which could cause a partial magnetic short circuit and result in a power loss from the blood pump's electric motor.

[0043] The drive unit according to Figure 2 may have at least two, at least three, at least four, at least five, or preferably six posts 40. A greater number of posts 40, for example nine or twelve, would be possible. Only two posts 40 are visible due to the cross-sectional view. The posts 40 and backplate 50 form a magnetic core 400 of the drive unit 4, which may have a diameter of less than 10 mm.

[0044] The magnetic core 400 includes the posts 40 and backplate 50 of the drive unit 4 as a single piece, or monoblock. The monoblock is made of a discontinuous soft magnetic material that is discontinuous in terms of electrical conductivity. The discontinuous soft magnetic material includes multiple sheets 85 made of a ferromagnetic material and stacked together. Specifically, the sheets 85 may be made of Vacoflux® 48, Vacoflux® 50, Vacodur® 49, or Vacodur® 50. The stacking direction is aligned along the longitudinal axis LA of the posts 40, indicated by the arrow DL. As shown, the posts 40 are aligned parallel to the rotational axis 10.

[0045] The coil winding 44 extends all the way to the impeller-side end 420 of the post 40. This has the advantage that magnetomotive force can be generated along the entire post 40. The magnetic core 400 has a protrusion 401 that is located at the rear end 450 of the post 40 and extends radially relative to the post 40. This protrusion 401 can serve as a stop for the coil winding 44 toward the backplate 50. The integrated magnetic core 400 provides high rigidity between the backplate 50 and the post 40, making it possible to omit a spacer between the posts 40 at the impeller-side end 420 of the post. The advantage of the integrated magnetic core 400 is that it achieves optimal magnetic coupling between the post 40 and the backplate 50. The magnetic core 400 can have a diameter of less than 10 mm.

[0046] 3A-3C illustrate the manufacturing process of a magnetic core 400 for a drive unit 4 of the drive unit impeller arrangement shown in FIG. 2. FIG. 3A shows, in perspective view, a cube-shaped monoblock 9, which forms a workpiece for manufacturing the magnetic core 400. The monoblock 9 is made of a discontinuous soft magnetic material that is discontinuous in electrical conductivity. It comprises sheets 85 oriented along a stacking direction DL, which extends along the main plane of the sheets 85. Each sheet 85 is joined to its adjacent individual sheet by a joining layer of non-conductive material, not explicitly shown in FIGS. 3A-3C.

[0047] 3B shows the magnetic core 400 in a partially manufactured state, after it has been machined, e.g., turned, from the cubic monoblock 9 into a substantially cylindrical body 94. The machining process creates a protrusion 401. The reduced diameter portion 404 of the body 94 forms the periphery of the post 40 of the magnetic core 400 and has a diameter corresponding to the outer radius of the outermost convex side of the post 40.

[0048] The body 94 is then further machined to produce the magnetic core 400, as shown in FIG. 3C. Electrical discharge machining can be used in this production process. In particular, wire-cutting electrical discharge machining can be applied to create slots 49 that separate the posts 40. Inside these slots, space is provided for the coil windings 44. At the bottom of the slots 49 is an intermediate area 59 of the integrated backplate 50, which extends between the rear ends of the posts 40. The intermediate area is integrated with the posts 40 and the backplate 50. In other words, the entire magnetic core 400 is formed from a monoblock 9.

[0049] The lamination direction DL in the magnetic core 400 is parallel to the rotation axis 10. It is permissible for the lamination direction DL in the base plate 50 not to be parallel to the magnetic flow between the posts 40 within the base plate 50. The magnetic core 400 can also be manufactured from a wound soft magnetic sheet material separated by non-conductive layers. In this case, the lamination direction DL in the base plate 50 is always along the circumferential direction. This is advantageous in terms of avoiding the generation of eddy currents in the magnetic flux within the base plate 50.

[0050] 4A to 4C show how one or more welds can be provided on the surface of the integrated magnetic core manufactured according to FIGS. 3A to 3C. Accordingly, in the illustrated embodiment, three weld seams 82, 83 are provided on one side of the cubic monoblock 9. The weld seams 82, 83 are welded at a distance from each other and are located on the cross section of the monoblock 9's body 94 to be cut. The weld seams 82, 83 extend perpendicular to the stacking direction DL of the sheets 85. In this way, the discontinuous soft magnetic material sheets are interconnected. Instead of three weld seams, more weld seams or a single wide weld may be provided. Additionally, a similar weld seam may be provided on the opposite side of the monoblock 9 (not shown). Instead of or in addition to the welds on the opposite side, one or more weld seams may be provided on the side of the monoblock 9 flush with the backplate 50, completely or at least partially encircling the backplate 50. These weld seams 82, 83 not only mechanically connect the sheets 85 better to each other, but also electrically. This has the advantage that current can flow from any location in the discontinuous soft-magnetic material to the respective electrical connection locations on the body 94, as may be required for electrical discharge machining. This significantly simplifies electrical discharge machining. Furthermore, a higher process reliability is achieved, since the backplate post unit to be cut into the body 94 is not disassembled due to delamination. Laser welding is preferably used. It may be advantageous to apply welding power twice or more times to the same weld.

[0051] FIGS. 5A-5D illustrate various embodiments of the post 141 in cross section. In the embodiments shown in FIGS. 5A-5D, the post is slotted, i.e., formed from multiple sheets 171 insulated from one another by insulating layers 172. The insulating layers 172 may contain adhesive, lacquer, baked enamel, etc. In the embodiments shown in FIGS. 5A and 5B, the sheets 171 have a uniform thickness. This thickness may range from 25 pm to 450 pm. The sheet 171 shown in FIG. 5A has a greater thickness than the sheet 171 shown in FIG. 5B. The sheets in FIG. 5C have different thicknesses, with the center sheet having the greatest thickness and the outermost sheets having the least thickness. This may be advantageous because eddy currents in the side regions of the post are more critical and can be reduced by using thinner sheets. Because eddy currents in the central area are less critical, a relatively thick center sheet may help improve magnetic flux. Other orientations of the sheet 171 are possible, as illustrated in FIG. 5D, so long as the soft magnetic material in the cross section shown, i.e., in the cross section transverse to the direction of magnetic flux, is discontinuous or broken.

[0052] If the post comprises or is composed of layered sheets of magnetic material, e.g., laminated sheets, there is a risk that the sheets in the post adjacent to the slot will become very thin and thus be completely burned away due to the heat generated by the EDM or alternative manufacturing method. As a result, the motor parameters of the three motor phases in the resulting motor may be biased due to uneven burn-away of the post material. Therefore, in the following embodiments shown in FIGS. 6B, 7D, 8E, and 10B, the orientation of the sheets in the posts relative to the axis of rotation is substantially the same for all posts, and this orientation is selected so that no sheets are oriented parallel to the slot. In this way, no sheets will become very thin and will not be burned away during the cutting process. Furthermore, because the orientation of the sheets in the posts relative to the axis of rotation is the same for all posts, and therefore the EDM process for creating the slots affects all posts in substantially the same way, all three motor phases in the resulting motor will be similarly affected and will not be biased relative to each other.

[0053] In the embodiment shown in Figures 6A and 6B, original magnetic material sheets 85 are prepared in the form of sleeves. These sleeves are then magnetically annealed to achieve and optimize the desired magnetic properties. Magnetic annealing results in a uniform atomic grid with minimal distortion and a homogeneous magnetic state. Preferably, the annealing is performed in a vacuum or under protective and / or reactive gases.

[0054] Then, sleeve-shaped sheets 85 are arranged along concentric circles around the rotation axis (FIG. 6A) and bonded together, preferably with an epoxy adhesive. Slots 49 are then cut into the monoblock 9, as shown in FIG. 6B, to form the posts 40. As can be seen, the soft magnetic material sheets 85 in each post 40 are arranged concentrically around the rotation axis. That is, the orientation of the sheets 85 in each post 40 relative to the rotation axis is the same for all posts.

[0055] 7A-7D illustrate the manufacturing process for a magnetic core 400 according to the present disclosure. First, a single sheet 85 is magnetically annealed to achieve and optimize the desired magnetic properties. This results in a uniform atomic grid with minimal distortion and a homogeneous magnetic state. Preferably, the annealing is performed in a vacuum or under protective and / or reactive gases.

[0056] Thereafter, the monoblock 9 is created, i.e., the single sheet 85 is wound around the axis of rotation 10 to form a cylindrical body 94, whereby the sheets 85 are circumferentially arranged around the axis of rotation 10. Preferably, a bonding layer of a non-conductive material, for example an adhesive, is provided between the layered sheets 85. The adhesive may be an epoxy adhesive.

[0057] In this embodiment, the end 87 of the sheet 85 is secured by two spot welds 86 on the outer periphery of the monoblock 9 (FIG. 7A). Of course, the end 87 of the sheet 85 could also be secured by adhesive. In particular, the spot welds 86 firmly secure the end 87 of the wound sheet 85 to the sheet 85 itself, preventing unwinding. To facilitate winding, the sheet 85, and thus the monoblock 9, has an axial extension longer than the intended axial extension of the final magnetic core 400. For example, the height of the monoblock 9 can be 10 mm. After the spot welds 85 are applied, the monoblock 9 is cut to a length of, for example, 6.85 mm, as shown in FIG. 7B. This cutting is preferably performed by electrical discharge machining.

[0058] Next, three weld seams 83 are provided on at least one side of the cylindrical monoblock 9, preferably on both sides of the cylindrical monoblock 9. The weld seams 83 intersect each other approximately at the axis of rotation 10, thereby connecting the discontinuous sheets of soft magnetic material together. Instead of the three weld seams, more weld seams or a single wide weld may be provided. Additionally, a similar weld seam may be provided on the opposite side of the monoblock 9 (not shown). Instead of or in addition to the welds on the opposite side, one or more weld seams may be provided flush with the backplate 50 on the side of the monoblock 9, completely or at least partially encircling the backplate 50. This not only improves the mechanical connection of each coil of the sheet 85 to the other coils of the sheet 85 via the weld seams 83, but also electrically connects all of the coils. The latter has the advantage that current, such as that required for electrical discharge machining, can be passed from any location in the discontinuous soft magnetic material to each electrical connection location in the body 94. This significantly facilitates electrical discharge machining. Furthermore, a higher process reliability is achieved, since the backplate post unit to be cut into the body 94 will not be disassembled due to delamination. Laser welding is preferably applied. It may be advantageous to apply welding power twice or more times to the same weld.

[0059] The next production step, cutting the slots 49, is shown in FIG. 7D. Electrical discharge machining can be used for this. In particular, wire-cutting electrical discharge machining can be applied to create the slots 49 that separate the posts 40. The slots provide space for the coil windings 44. At the base of the slots 49, an intermediate area 59 of the integrated backplate 50 extends between the rear ends of the posts 40. This intermediate area 59 is integrated with the posts 40 and the backplate 50. Thus, the entire magnetic core 9 is formed from a monoblock 9. As shown in FIG. 7D, the slots 49 are cut along the weld seam 83. It may be desirable to extend the weld seam 83 slightly longer than the slots 40 so that the entire weld seam 83 is not removed when the slots 49 are cut. Rather, a small portion of the weld seam 83 may remain in the final magnetic core 400 after the slots 49 are cut.

[0060] 8A-8E show a variation of the embodiment shown in FIGS. 7A-7C. Here, as shown in FIG. 8A, a sheet 85 that has already been magnetically annealed is wound onto a first support member 88. Prior to the winding, one end of the sheet 85 is attached to the first support member 88 by welding or adhesive (FIG. 8A). The sheet 85 is then wound onto the first support member 88, for example, 20-25 turns. Preferably, a bonding layer made of a non-conductive material is provided between the first support member 88 and the layered sheet 85, as well as between the coils of the layered sheet 85. The bonding layer may be an adhesive, such as an epoxy adhesive. Additionally, a non-conductive surface layer may be applied to the sheet 85.

[0061] That is, the first support member 88 forms the radially innermost portion of the cylindrical body 94 of the monoblock 9. In this embodiment, the first support member 88 is a single-piece tubular member made of a ferromagnetic material, such as Vacoflux® 48, Vacoflux® 50, Vacodur® 49, or Vacodur® 50. As can be seen from Figures 8A and 8B, the first support member 85 has a greater thickness than the sheet 85. In addition, the first support member 88 is magnetically annealed prior to winding.

[0062] Alternatively or in addition to spot welding or gluing on the outer periphery of the monoblock 9, a second support member 91 is provided. The second support member 91 is also a single-piece tubular member made of a ferromagnetic material, such as Vacoflux® 48, Vacoflux® 50, Vacodur® 49, or Vacodur® 50. Furthermore, it is preferable to subject the second support member 91 to magnetic annealing in advance. The second support member 91 forms the radially outermost portion of the cylindrical body 95 of the monoblock 9. The second support member 91 may be press-fit onto the wound sheet 85 or may be secured in another suitable manner, such as by heat shrinking. Furthermore, a bonding layer of a non-conductive material, such as an adhesive, may be provided between the sheet 85 and the second support member 91. The adhesive may be an epoxy adhesive.

[0063] The next production step is shown in Figure 8D, in which the monoblock 9 is cut to length, for example to 6.85 mm. Preferably, electrical discharge machining is used to cut the monoblock 9 to length. Three weld seams 83 are then provided on at least one side of the cylindrical monoblock 9. Preferably, three weld seams 83 are provided on both sides of the cylindrical monoblock 9. The weld seams 83 intersect each other approximately at the axis of rotation 10. In this way, the discontinuous sheets of soft magnetic material are joined together. Instead of three weld seams, more weld seams or a single wide weld may be provided. Additionally, a similar weld seam may be provided on the opposite side of the monoblock 9 (not shown).

[0064] The next production step, cutting slots 49, is shown in Figure 8E. Slots 49 are cut as described in detail above in connection with Figure 7D. As shown in Figure 8E, after cutting slots 49, first support member 88 includes a first tubular portion 89 and a plurality of first fingers 90 extending from first tubular portion 89. First tubular portion 89 defines the inner periphery of backplate 50. Each of first fingers 90 defines the inner periphery of one of posts 40. In other words, first support member 88 defines the innermost layer of magnetic core 400 (i.e., the layer closest to the axis of rotation).

[0065] Similarly, as shown in Figure 8E, after the slots 59 are cut, the second support member 91 includes a second tubular portion 92 and a plurality of second fingers 93 extending from the second tubular portion 92. The second tubular portion 92 defines the outer periphery of the backplate 50. Each of the plurality of second fingers 93 defines the outer periphery of one of the plurality of posts 40.

[0066] The first support member 88 and the second support member 91 prevent those sheets 85 in the post 40 adjacent to the slot 49 from being completely burned away by the heat generated by the EDM or alternative manufacturing method.

[0067] A further embodiment is shown in Figure 9, in which the monoblock 9 is provided with only a single support member 91, namely the second support member 91. That is, after the sheet 85 has been wound, the second support member 91 is provided around the so formed multiblock 9, as detailed above, and then the slots are cut.

[0068] 10A and 10B show a further embodiment, substantially similar to that shown in FIGS. 6A and 6B. Here, sheets 85 of magnetic material are provided as concentric rings along and centered on the axis of rotation 10. That is, the sheets 85 are stacked axially and radially. Thus, the individual rings can be made by stamping, laser cutting, or any other suitable forming process. The individual rings are stacked together via a bonding layer of a non-conductive material, such as an adhesive. The adhesive may be an epoxy adhesive.

[0069] The magnetic core 400 shown in FIGS. 3C, 4C, 6B, 7D, 8E, and 10B can be partially or completely coated with a thin layer. The coating can be applied to the outer periphery of the posts 40. The coating can also be applied to the outer periphery of the backplate 50. The end faces of the posts 40 on the proximal ends 420 can also be coated. Preferably, the surface of the backplate 50 facing away from the posts is left uncoated. The coating preferably provides electrical insulation and mechanical stability, and does so with a small thickness. Therefore, the coating can be a DLC coating, a perylene coating, or a polyamide coating. In the embodiments shown in FIGS. 6B, 7D, 8C, and 10B, the slots 49 do not extend axially through the entire monoblock 9, but have a depth that defines the length of the posts 40 and the thickness of the backplate 50 to which they are integrated. In an alternative embodiment, slots 85 may extend through the entire monoblock, separating posts 40 from the monoblock, which may then be assembled into the motor along with other components, such as a separate backplate 50.

[0070] [Example Implementation] As noted above, the technology described herein can be implemented in a variety of ways. In that regard, the foregoing disclosure is intended to encompass, but is not limited to, the systems, methods, and combinations and subcombinations thereof described in accordance with the exemplary implementations set forth below. Preferred embodiments are described in the following paragraphs: A1 A blood pump that is percutaneously inserted into a patient's blood vessel, a pump casing having a blood flow inlet and a blood flow outlet; a pump element disposed within the pump casing so as to be rotatable about an axis of rotation and to convey blood from the blood inlet to the blood outlet; a drive unit for rotating the pump element; The drive unit comprises: a magnetic core having a plurality of posts arranged around the rotation axis and a back plate connecting the posts, and a coil winding, the coil winding being disposed around each of the posts; the coil windings are controllable to generate a rotating magnetic field, and the pump element includes a magnetic structure arranged to interact with the rotating magnetic field to cause rotation of the pump element. Blood pump. A2. A blood pump according to paragraph A1, wherein the magnetic core comprises or consists of at least one sheet of soft magnetic material. A3. A blood pump according to paragraph A2, wherein said at least one sheet extends at least partially circumferentially around said axis of rotation within each post, said at least one sheet being preferably a layered sheet. A4. A blood pump according to paragraph A1, A2 or A3, wherein the material of the plurality of posts is integral with the material of the backplate. A5 A blood pump according to any one of the preceding paragraphs A1 to A4, wherein the magnetic core has a first support member, the first support member has a first tubular portion and a plurality of first fingers extending from the first tubular portion, the first tubular portion forms the inner surface of the back plate, and each of the plurality of first fingers forms the inner surface of one of the plurality of posts. A6 A blood pump according to any one of the preceding paragraphs A1 to A5, wherein the magnetic core has a second support member, the second support member has a second tubular portion and a plurality of second fingers extending from the second tubular portion, the second tubular portion forms the outer surface of the back plate, and each of the plurality of second fingers forms the outer surface of one of the plurality of posts. A7. A blood pump according to any one of the preceding paragraphs A1 to A6, comprising at least one weld in the material of said magnetic core bridging a discontinuity in electrical conductivity. A8. The blood pump according to paragraph A7, wherein at least one of the at least one weld is located on a surface of the backplate opposite the post. A9. The blood pump according to paragraph A7 or A8, wherein the at least one of the at least one weld is located on an end face of a post opposite the backplate. A10. A blood pump according to any one of the preceding paragraphs A1 to A9, wherein the magnetic core comprises or is composed of a plurality of layered sheets, the sheets being stacked along the axial direction. A11 A blood pump according to any one of the preceding paragraphs A1 to A10, wherein the magnetic core comprises or is composed of a plurality of layered sheets, the sheets being stacked radially. A12. A blood pump according to any one of the preceding paragraphs A1 to A11, wherein said magnetic core is at least partially covered with a coating. A13. A blood pump according to paragraph A12, wherein the coating is a DLC coating, a perylene coating or a polyamide coating. A14. A blood pump according to paragraph A12 or A13, wherein the coating is applied on the outer circumferential surface of the post. A15. A blood pump according to any one of the preceding paragraphs A12 to A14, wherein said coating is applied onto the outer circumferential surface of said back plate. A16. A blood pump according to any one of the preceding paragraphs A12 to A15, wherein said coating is applied onto an axial end face of said post. A17. A blood pump according to any one of the preceding paragraphs A1 to A16, wherein the magnetic core is at least partially made of a material selected from Vacoflux® 48, Vacoflux® 50, Vacodur® 49 and / or Vacodur® 50. A18 A blood pump according to any one of the preceding paragraphs A2 to A17, wherein, inside each of said posts, said seats are arranged concentrically about said axis of rotation. B1 A method of manufacturing a magnetic core for a drive unit of a blood pump, the magnetic core having an axis of rotation and a plurality of posts arranged about the axis of rotation and a back plate connecting the posts, the method comprising the steps of: preparing a monoblock; and cutting slots in the monoblock to produce the posts and to arrange the posts about the axis of rotation. B2. A method according to paragraph B1, wherein said monoblock comprises or consists of at least one layered sheet of soft magnetic material, said at least one sheet extending at least partially circumferentially about said axis of rotation. B3. The method according to paragraph B1 or B2, wherein said monoblock preparing step comprises winding a single sheet about said axis of rotation to form at least one layered sheet. B4. A method according to paragraph B3, wherein the sheet winding step includes winding the sheet around a first support member, the first support member preferably being a single-piece tubular member. B5. The method according to paragraph B4, wherein said first support member is annealed prior to said winding step, said annealing preferably being magnetic annealing. B6. A method according to paragraph B4 or B5, wherein the sheet winding step comprises attaching the sheet to the first support member by gluing or welding. B7. The method according to any one of the preceding paragraphs B1 to B6, further comprising the step of providing a second support member on the outer periphery of the monoblock prior to cutting the slots. B8. A method according to paragraph B7, wherein the second support member is annealed before being provided on the outer peripheral surface of the monoblock, the annealing preferably being magnetic annealing. B9 A method according to any one of the preceding paragraphs B3 to B8, further comprising the step of providing bonding layers of a non-conductive material between the layers of the sheet, and / or between the sheet and the first support member, and / or between the sheet and the second support member. B10. The method according to paragraph B9, wherein the bonding layer comprises an adhesive, which is preferably an epoxy adhesive. B11. A method according to any one of the preceding paragraphs B1 to B10, wherein cutting the slots in the monoblock generates the backplate such that it forms a single, integral piece with the posts. B12. A method according to any one of the preceding paragraphs B1 to B11, further comprising the step of annealing said at least one sheet or said monoblock prior to said slot cutting, said annealing preferably being magnetic annealing. B13. A method according to any one of the preceding paragraphs B1 to B12, further comprising the step of providing at least one weld on the outer surface of the monoblock prior to said slot cutting, preferably providing at least one spot weld on the outer surface of the monoblock. B14. The method of any one of the preceding paragraphs B3 to B13, further comprising adhering an edge of said at least one layered sheet to an outer surface of said at least one layered sheet prior to said slot cutting. B15. A method according to any one of the preceding paragraphs B1 to B14, wherein said slots are cut using electrical discharge machining. B16. A method according to paragraph B15, wherein said slots are cut using wire cutting by electrical discharge machining. B17. A method according to any one of the preceding paragraphs B1 to B13, wherein said slots are cut using electrochemical machining. B18. A method according to any one of the preceding paragraphs B1 to B17, wherein said monoblock comprises at least one punched ring.

[0071] As used herein, the terms "approximately," "about," "substantially," and similar terms are intended to have broad meanings consistent with accepted usage and common sense among those skilled in the art to which the subject matter of this disclosure pertains. Those skilled in the art who review this disclosure should understand that these terms are intended to describe certain features described, but not to limit the scope of those features to the precise numerical ranges presented. Accordingly, these terms should be interpreted as indicating insubstantial or minor modifications or variations of the described subject matter that are believed to be within the scope of the present disclosure. As used herein, the terms "at least partially" and "partially" mean both partially and entirely or completely, respectively. Additionally, the terms "first," "second," etc., do not denote a particular order but are used merely to distinguish one element from another.

[0072] As used herein, "proximal" and "distal" refer to those points relative to the medical staff or physician, and thus, "proximal" refers to those points that are relatively closer to the physician when the guide ear is being introduced into the patient, while "distal" refers to those points that are relatively further away from the physician. [Explanation of symbols]

[0073] 1 blood pump, 2 pump casing, 3 pump elements / impellers, 4 drive units, 6 circuit boards, 9 monoblocks, 10 axis of rotation, 11 First bearing, 12 second bearing, 13 retaining member, 14 aperture, 15 pin, 21 Blood flow inlet; 22 Blood flow outlet, 23 cannula, 24 aisles, 25 catheters, 26 Conductive wire, 31 blades, 32 magnets, 37 York, 40 posts, 44 coil windings, 49 slots, 50 backplate, 59 intermediate area, 82 welded seams, 83 Welded seams, 85 seats, 86 Spot welds, 87 Sheet edge, 88 first support member, 89 first tubular section, 90 First Finger, 91 second support member, 92 second tubular part, 93 Second Finger, 94 cylindrical body, 141 posts, 171 seats, 172 insulating layer, 400 magnetic core, 401 protrusion, 404 parts, 420 Impeller end of post, 450 rear end of post, DL stacking direction, LA long axis.

Claims

1. A blood pump (1) that is percutaneously inserted into a patient's blood vessel, a pump casing (2) having a blood inlet (21) and a blood outlet (22); a pump element (3) arranged in the pump casing (2) so as to be rotatable about a rotation axis (10) and to convey blood from the blood inlet (21) to the blood outlet (22); a drive unit (4) for rotating the pump element (3), the drive unit (4) comprising a magnetic core (400) having a plurality of posts (40) arranged around the rotation axis (10) and a back plate (50) connecting the posts (40), and a coil winding (44), the coil winding (44) being disposed around each of the posts (40); Equipped with the coil winding (44) is controllable to generate a rotating magnetic field, and the pump element (3) comprises a magnetic structure (32) arranged to interact with the rotating magnetic field to cause rotation of the pump element (3); The magnetic core (400) comprises or is composed of at least one layered sheet (85) of soft magnetic material, the at least one sheet (85) extending at least partially circumferentially around the axis of rotation (10) within each post (40).

2. 2. The blood pump (1) according to claim 1, wherein the material of the plurality of posts is integral with the material of the back plate (50).

3. 3. A blood pump (1) according to claim 1 or 2, wherein the magnetic core (400) comprises a first support member (88), the first support member comprising a first tubular portion (89) and a plurality of first fingers (90) extending from the first tubular portion (89), the first tubular portion (89) forming an inner circumferential surface of the backplate (50), and each of the plurality of first fingers (90) forming an inner circumferential surface of one of the plurality of posts (40).

4. 4. A blood pump (1) according to any one of claims 1 to 3, wherein the magnetic core (400) comprises a second support member (91), the second support member (91) comprising a second tubular portion (92) and a plurality of second fingers (93) extending from the second tubular portion (92), the second tubular portion (92) forming an outer circumferential surface of the back plate (50), and each of the plurality of second fingers (93) forming an outer circumferential surface of one of the plurality of posts (40).

5. A blood pump (1) according to any one of claims 1 to 4, comprising at least one weld (82, 83, 86) in the soft magnetic material bridging a discontinuity in electrical conductivity.

6. 6. A blood pump (1) according to claim 5, wherein at least one of the at least one welded portion (82, 83, 86) is arranged on a surface of the back plate (50) that is opposite to the post (40), and / or at least one of the at least one welded portion is arranged on an end face of the post (40) that is opposite to the back plate (50).

7. 7. A blood pump (1) according to any one of claims 1 to 6, wherein the magnetic core (400) comprises or is composed of a plurality of layered sheets (85), the sheets (85) being stacked in the axial and / or radial directions.

8. A method for manufacturing a magnetic core (400) for a drive unit (4) of a blood pump (1), the magnetic core having a rotation axis (10) and a plurality of posts (40) arranged around the rotation axis (10) and a back plate (50) connecting the posts (40), comprising: providing a monoblock (9) comprising or consisting of at least one layered sheet (85) of soft magnetic material, the at least one sheet (85) extending at least partially circumferentially around said axis of rotation (10); cutting slots in the monoblock (9) so that the posts (40) emerge and are positioned about the axis of rotation (10); A method having the following.

9. 9. The method according to claim 8, wherein the monoblock preparation step comprises the step of winding a single sheet (85) about the axis of rotation (10) to form the at least one layered sheet (85).

10. 10. The method according to claim 9, wherein the step of winding the sheet (85) includes winding the sheet (85) around a first support member (88), the first support member (88) being preferably a single-piece tubular member.

11. 11. The method according to any one of claims 8 to 10, further comprising the step of providing a second support member (91) on the outer periphery of the monoblock (9) prior to cutting the slots (49).

12. A method according to any one of claims 8 to 10, wherein when cutting the slots (49) in the monoblock (9), the backplate (50) is generated such that it forms a single integral piece with the posts (40).

13. 13. The method according to any one of claims 8 to 12, further comprising the step of annealing said at least one sheet (85) or said monoblock (9) prior to cutting said slots (49), said annealing preferably being magnetic annealing.

14. 12. The method according to any one of claims 8 to 11, further comprising the step of providing at least one weld (82, 83, 86) on an outer surface of the monoblock (9) prior to cutting the slot (49).

15. A blood pump (1) having a drive unit (4) with a magnetic core (400), A blood pump manufactured according to any one of claims 8 to 14.

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