Blood pump

Abstract

An intravascular blood pump (1) comprises a pump housing (2) having a blood inflow (21) and a blood outflow (22), and an impeller (3) arranged in the pump housing (2) to be rotatable about an axis of rotation, wherein the impeller (3) has blades (31) which are dimensioned and shaped for transporting blood from the blood inflow (21) to the blood outflow (22). The blood pump (1) further comprises a drive unit (4) for rotating the impeller (3), the drive unit (4) comprising a plurality of posts (40) arranged about the axis of rotation (10), wherein each of the posts (40) comprises a stem portion (41) and a head portion (42). Coil windings (470) around the posts are controllable in sequence to generate a rotating magnetic field. The drive unit (4) further comprises a back plate (50) which engages with the end portions (44) of the stem portions (41) of the posts (40) opposite the head portions (42).

Description

[0001] Divisional application

[0002] This application is a divisional application of Chinese patent application No. 201780018607.4, filed on March 21, 2017, entitled "Blood Pump". Background Technology

[0003] This invention relates to a blood pump for maintaining blood flow in a patient's blood vessels, particularly an intravascular blood pump inserted through the skin into a patient's blood vessels. The blood pump has an improved drive unit that allows for a reduction in the pump's outer diameter.

[0004] Different types of blood pumps are known, such as axial flow blood pumps, centrifugal blood pumps, or hybrid blood pumps where blood flow is caused by both axial and radial forces. Intravascular blood pumps are operated by means of a catheter inserted into a patient's blood vessel, such as the aorta. A blood pump typically comprises a pump housing with a blood inlet and a blood outlet connected by a channel. To allow blood to flow from the blood inlet along the channel to the blood outlet, an impeller or rotor is rotatably supported within the pump housing, wherein the impeller is provided with blades for delivering blood.

[0005] Blood pumps are typically driven by a drive unit, which can be an electric motor. For example, US2011 / 0238172A1 discloses an external blood pump with an impeller that can be magnetically coupled to an electric motor. The impeller includes a magnet disposed adjacent to a magnet in the electric motor. Rotation of the electric motor is transmitted to the impeller due to the attraction between the magnets in the impeller and the electric motor. Also known from US2011 / 0238172A1 is a method utilizing a rotating magnetic field to reduce the number of rotating parts, wherein the drive unit has multiple static columns arranged around a rotation axis, each column carrying a coil winding and serving as a magnetic core. A control unit sequentially supplies voltage to the coil winding to generate a rotating magnetic field. To provide sufficiently strong magnetic coupling, the magnetic force must be high enough, which can be achieved by supplying a sufficiently high current to the drive unit or by providing a large magnet; however, providing a large magnet results in a larger overall diameter of the blood pump. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a blood pump having magnetic coupling between a drive unit and an impeller, preferably an intravascular blood pump or a transvalvular blood pump, wherein the blood pump has a compact design, particularly having a sufficiently small outer diameter to allow the blood pump to be inserted via a blood vessel, vein, artery or transvalvular.

[0007] This objective according to the invention is achieved by a blood pump having the features of the invention.

[0008] According to the invention, a blood pump, preferably an intravascular blood pump and which may be one of an axial flow blood pump, a centrifugal blood pump, and a hybrid blood pump, includes a drive unit for rotating an impeller. The drive unit includes a plurality of columns arranged around a rotation axis, such as at least two, at least three, at least four, at least five, or preferably six columns. A greater number of columns is also possible, such as eight, ten, or twelve. The number of columns is preferably even for impeller balancing control, but it can also be odd, such as three or five. Each column includes a rod portion and a head portion, the head portion pointing towards the impeller. To generate a rotating magnetic field, coil windings are arranged around the rod portion of each column, the coil windings being sequentially controllable to generate the rotating magnetic field. The impeller includes at least one magnet arranged to magnetically couple the impeller to the drive unit, i.e., to interact with the rotating magnetic field to cause rotation of the impeller.

[0009] Compared to conventional electric motors, drive units that generate rotating electromagnetic fields allow for a simplified mechanical structure of the blood pump by reducing the number of moving parts. This also reduces wear because contact supports, unlike those used for electric motors, are not required. The magnetic coupling between the drive unit and the impeller not only causes the impeller to rotate but also allows for proper alignment of the impeller. Specifically, the magnetic coupling can provide both axial and radial support.

[0010] To increase the density of magnetic coupling between the magnets of the drive unit and the impeller, it may be advantageous to activate multiple columns simultaneously, where "activation" means supplying power to the corresponding coil windings to generate the corresponding magnetic pole magnets. For example, more than half of the columns can be activated simultaneously, such as four out of six columns, depending on the number of columns and the number of magnets in the impeller. Preferably, the arrangement of the activated and inactive columns is rotationally symmetrical, and the columns are controlled in pairs.

[0011] The drive unit also includes a backplate that engages with the ends of the rod portions of a plurality of columns opposite to the head portions. In one embodiment, the backplate may include a plurality of holes preferably arranged at equal angular distances around the axis of rotation to receive the end portions of the rod portions. However, it should be understood that the columns may otherwise be permanently or releasably attached, connected, or secured to the backplate. The backplate is particularly used to close the magnetic flux loop to promote and increase magnetic flux generation and improve coupling. Because the magnetic flux is increased by the backplate, the overall diameter of the blood pump can be reduced, which is particularly advantageous for intravascular blood pumps. The arrangement including the columns and the backplate also allows for high frequencies of the blood pump, i.e., the blood pump can operate at high speeds. Furthermore, since the backplate engages the columns, it provides structural stability to the column assembly.

[0012] The backplate can be made of magnets or other materials suitable for closing the magnetic flux loop, preferably cobalt steel. The diameter of the backplate can be from about 3 mm to 9 mm, such as 5 mm or 6 mm to 7 mm. The thickness of the backplate can be from about 0.5 mm to about 2.5 mm, such as 1.5 mm. The outer diameter of the blood pump can be from about 4 mm to about 10 mm, preferably about 6 mm. The outer diameter of the multi-column assembly, particularly the maximum outer diameter of the multi-column assembly measured at the head portion of the columns, can be from about 3 mm to 8 mm, such as 4 mm to 6 mm, preferably 5 mm.

[0013] The dimensions of the column, particularly its length and cross-sectional area, can vary and depend on a variety of factors. Unlike the size of the pump (e.g., outer diameter), which depends on the pump's application, the column dimensions are determined by electromagnetic properties that are tuned to achieve the desired performance of the drive unit. One factor is the flux density achievable with the minimum cross-sectional area of ​​the column. The smaller the cross-sectional area, the greater the current required to obtain the desired magnetic flux. However, a larger current generates more heat in the coil wire due to resistance. This means that while a "thin" column is preferred to reduce the overall size, this would require a large current and thus lead to undesirable heat. The heat generated in the wire also depends on the length and diameter of the wire used for the coil winding. Shorter wire lengths and larger wire diameters are preferred to minimize winding losses (often referred to as "copper losses" or "copper power losses" if copper wire is used, which is the general case). In other words, a smaller wire diameter generates more heat compared to a thicker wire for the same current; preferred wire diameters are, for example, 0.05 mm to 0.2 mm, such as 0.1 mm. Other factors affecting the size of the post (i.e., the post containing the windings) and the performance of the drive unit are the number of windings and the outer diameter of the windings. A larger number of windings can be arranged in more than one layer around each post; for example, two or three layers can be provided. However, the more layers there are, the more heat will be generated due to the increased length of the wires in the outer layers with larger winding diameters. Since longer wires have higher resistance compared to shorter wires, the increased wire length can generate even more heat. Therefore, a single-layer winding with a small winding diameter is preferred.

[0014] The typical number of windings (which in turn depends on the length of the post) can be from about 50 to about 150, for example, 56 or 132.

[0015] In one embodiment, the impeller may further include a yoke or backplate attached to at least one magnet of the impeller, preferably on the side of the impeller away from the drive unit, for example, between the magnet and the blades of the impeller. Similar to a backplate attached to the end of a rod of a column, the yoke or backplate of the impeller serves to close the magnetic flux loop, thereby increasing the generation of magnetic flux and enhancing coupling. It can be made of magnetic steel, preferably cobalt steel.

[0016] The column can also be made of magnet steel. Preferably, the drive unit, including the column and back plate, is made of cobalt steel. The use of cobalt steel helps to reduce the size of the pump, especially its diameter. Utilizing the highest magnetic permeability and the highest saturation magnetic flux density among all magnet steels, cobalt steel produces the largest magnetic flux for the same amount of material.

[0017] If the columns are magnetically insulated from each other, it may be more advantageous for the efficiency and performance of the drive unit. Therefore, a magnetically insulating material can be placed between the head portions of adjacent columns to separate them and retain the respective magnetic fields within their respective columns. The magnetically insulating material can be a magnetic material whose magnetic field will be retained within its respective column by the electromagnetic field induced by the coil windings. At least an air gap or other insulating material, i.e., a non-conductive material, can be provided between the head portions of the columns to prevent short circuits between them.

[0018] In one embodiment, at least one head portion of the column, preferably each head portion of the column, has a top surface that is inclined at an angle relative to a plane perpendicular to the axis of rotation. The distance between the axis of rotation and the center of the inclined surface in the radial direction may be less than or equal to the distance between the axis of rotation and the center of the cross-sectional area of ​​the corresponding rod portion of the column in the radial direction. The center of the surface or area in the radial direction is the center between the innermost and outermost radial points of the surface or area. In other words, the inclined top surface of the head portion, which is the impeller-facing surface, may extend obliquely or be inclined at an angle relative to the axis of rotation, and half or more of the inclined surface may be radially inwardly positioned relative to the center of the rod portion. This allows the outer diameter of the drive unit, and thus the outer diameter of the blood pump, to be kept to the minimum required for magnetically coupling the drive unit to the impeller. This reduced diameter design is particularly advantageous for intravascular blood pumps located within the patient's blood vessel during operation and can be configured by means of a catheter. Furthermore, the inclined coupling surface provides radial centering of the impeller. The aforementioned angle is preferably 45° relative to the plane perpendicular to the axis of rotation, but can be from about 0° to about 90°, preferably from about 30° to about 60°, and more preferably from about 40° to about 50°. The inclined surfaces of the column preferably face outwards radially, i.e., they form a convex shape. Alternatively, the inclined surfaces can face inwards radially to form a concave shape.

[0019] All the posts are preferably identical, such that the drive unit is symmetrical about the axis of rotation. However, it should be understood that the posts do not need to be exactly the same, as long as they are compatible to form the drive unit according to the invention. Preferably, however, the rod portions have the same length and the inclined surfaces of the head portions have the same inclination angle. Different posts can be arranged irregularly or regularly, such as in an alternating manner, to form the drive unit.

[0020] The inclined surfaces of the head portions of the at least one column, preferably, can be radially aligned or radially inward or outward positioned relative to the outermost radial surface of the coil winding of the corresponding column. The inclined surfaces preferably extend radially inward toward the axis of rotation beyond the corresponding rod portion to maximize the surface area of ​​the magnetic support while minimizing the outer diameter of the drive unit. For example, in axial projection, i.e., in a top view in the axial direction, the inclined surfaces of the head portions can be located within the coil winding, or can be aligned axially at least with the shaft or coil winding. In another embodiment, the head portions can extend radially and / or circumferentially beyond the outer periphery of the coil winding. In a plane perpendicular to the axis of rotation, the head portions can have a larger cross-sectional dimension than the corresponding rod portion, wherein the corresponding coil winding preferably does not extend beyond the head portion at least radially. In other words, the head portions can form a shoulder that can serve as a radial stop and an axial stop for the coil winding.

[0021] At least one of the head portions, preferably all of the head portions, may have a generally triangular or trapezoidal cross-section along a plane including the axis of rotation. In the assembled state, the inclined or sloping surfaces of the head portions may together form a conical or generally conical surface, such as a surface with a cross-section but generally forming a conical surface. Typically, the shape of the formed surface may be convex. Exemplarily, the head portions may be arranged together like fan-shaped blocks to form a circular device with a conical top surface. At least one magnet of the impeller may have or may form a conical or generally conical recess, the size and shape of which generally corresponds to the conical surface formed by the head portion of the column. Typically, the magnet may form a concave surface facing the convex surface formed by the column to improve magnetic coupling. In another embodiment, the arrangement of the concave and convex surfaces may be reversed, i.e., the head portion of the column may form a conical recess, while the magnet forms a convex conical surface.

[0022] The concave and convex surfaces of the drive unit and impeller can respectively form gaps, such that the distance between the surfaces is constant. However, preferably, the gap distance is not constant, but is chosen such that the cross-sectional area of ​​the gap is constant in the radial direction when viewed in the circumferential direction. In the latter case, the distance between the surfaces increases towards the axis of rotation. Combinations of the two cases are also conceivable. The shape and size of the gap between the impeller and the drive unit can contribute to the hydrodynamic bearing capability.

[0023] The impeller's magnets can be formed as a single piece, having a conical or generally conical recess corresponding to the shape of the head portion of the column, including gaps of varying distances as explained above. However, it should be understood that multiple magnets, such as two or more magnets, forming the conical recess, can be arranged around the axis of rotation in the impeller. These could be four magnets, preferably six, or even eight, ten, or twelve magnets. It is advantageous to have multiple magnets, preferably an even number, and more preferably a number corresponding to the number of columns, because the magnets can be arranged with alternating north / south oriented magnetic fields without dead zones. If the magnets are set as a single piece, dead zones are created at the transitions between the different oriented magnetic fields.

[0024] If the impeller comprises multiple magnets, the magnets can be arranged with virtually no gaps between them to increase the amount of magnetic material. However, it has been found that if the magnets are separated by gaps, particularly radially extending gaps, the efficiency of magnetic coupling does not decrease. This is due to the characteristics of the magnetic field and the gap between the drive unit and the impeller. If the magnets in the impeller are close to each other, the innermost magnetic field lines extending in an arch from one magnet (north) to the adjacent magnet (south) will not extend beyond the gap between the drive unit and the impeller; therefore, they will not reach the drive unit, meaning they contribute nothing to the impeller's drive. Thus, if gaps are provided between the magnets in the impeller, there is no loss of efficiency. The size of the gaps that can be provided between the magnets in the impeller without sacrificing drive efficiency depends on the size of the gap between the impeller and the drive unit, as can be calculated by a technician. The gaps between the impeller magnets can, for example, be used as cleaning pipes.

[0025] Generally, and regardless of whether the head portion forms a conical surface, the impeller magnet can have a surface facing the head portion of the column and inclined at an angle approximately corresponding to the angle of the inclined surface of the head portion. For example, this arrangement can be the opposite of the above arrangement, that is, the head portion of the column can form a concave surface, such as a conical recess, while the impeller magnet can form a convex surface, such as a conical surface.

[0026] Regardless of the inclination of the various surfaces, one or more magnets of the impeller can be radially aligned with the head portion of the column. However, in some embodiments, one or more magnets of the impeller can be radially offset relative to the head portion of the column, such as radially inward or radially outward. This radial offset can improve the stability and radial centering of the impeller because the magnetic force between the impeller and the drive unit has a radial component; however, if the magnets are radially aligned with the head portion of the column, the magnetic force is only directed approximately axially.

[0027] In one embodiment, the impeller may extend at least partially around the drive unit, particularly around the head portion of the column. In other words, the impeller may have an extension that overlaps with the drive unit in the circumferential direction. This means that magnetic coupling occurs not only in the region of the inclined surface of the head portion of the column but also on its radially outer surface. The impeller may have an increased diameter, particularly a diameter larger than that of the drive unit, allowing the impeller to extend around the head portion region of the column. Therefore, the impeller may have a recess with both a tapered portion and a cylindrical portion as described above. This design of the impeller improves magnetic coupling because the impeller and the drive unit are also coupled radially, where the magnetic field lines extend radially. In this region, due to the largest diameter, a high torque can be generated to drive the impeller.

[0028] In one embodiment, the intravascular blood pump may further include a housing surrounding the drive unit, the size and shape of which preferably correspond to the outer contours of a plurality of columns. Specifically, the housing may have a tapered axial end surface that corresponds to the shape of the surface formed by the inclined surface of the head portion of the columns. The opposite end may be open and may engage a backplate to close the housing. The housing serves as protection for the column assembly, particularly as protection against blood contact, which is especially useful for the coil windings. Preferably, the housing is disposed within the pump housing. Regardless of the presence of such a housing, the drive unit is preferably arranged within the pump housing. The housing is preferably made of a non-magnetic and non-conductive (i.e., electrically insulating) material that provides good heat transfer. The housing material may be, for example, aluminum.

[0029] The coil windings can be embedded in a thermally conductive matrix that is non-conductive (i.e., electrically insulating). The matrix protects the coil windings and transfers the heat generated by them. The material of the thermally conductive matrix can be a plastic material with additives to increase thermal conductivity. For example, the matrix may include epoxy resin with aluminum additives. The matrix can be formed by molding the material around and between the coil windings and subsequently curing the material.

[0030] Preferably, the drive unit has a central opening extending along the axis of rotation. The central opening may be formed by the head portion of the column and may be configured to receive an elongated pin, the size and dimensions of the axial end surface of which are designed to form a support surface for the impeller. This arrangement allows for a compact design of the blood pump, as the space between the columns is used for the pin. The other end of the pin may be supported by the pump housing. The central opening may also be configured for the insertion of a guidewire, etc., or may form a fluid path.

[0031] To enhance the cleaning flow through the gap between the impeller and the drive unit, a secondary blade assembly can be provided in the impeller. Specifically, the secondary blades can be disposed on the side of the magnet or multiple magnets facing the drive unit, i.e., within the gap between the impeller and the drive unit. The cleaning flow can be additionally or alternatively increased by channels recessed in the surface of the magnet facing the drive unit. These channels can extend, for example, radially or helically.

[0032] In one embodiment, one or more hydrodynamic supports may be provided to support the impeller. For example, the aforementioned secondary blades and channels may form a hydrodynamic support or, as described above, support the ability of a hydrodynamic support at least in terms of the size and shape of the gap between the impeller and the drive unit. Conversely, the impeller-facing surface of the drive unit, i.e., particularly the end surface of the housing encapsulating the drive unit, may be adapted to form a hydrodynamic support. The hydrodynamic support may be axial or radial, or both. In particular, due to the tapered shape of the interface between the impeller and the drive unit, hydrodynamic supports in both the radial and axial directions may be formed. Radial hydrodynamic supports may also be formed between the outer surface of the impeller and the inner surface of the pump housing. Specifically, a gap may be formed between the impeller and the pump housing, through which a certain amount of blood flow sufficient for the hydrodynamic support may pass and exit the pump housing through a separate blood outlet. The main blood flow exits the pump housing through the blood outlet and does not flow through the gap. Non-contact hydrodynamic supports can support the function of the drive unit by reducing friction. Attached Figure Description

[0033] The foregoing description of the invention and the following detailed description of preferred embodiments will be better understood when read in conjunction with the accompanying drawings. For the purposes of this disclosure, please refer to the accompanying drawings. However, the scope of this disclosure is not limited to the specific embodiments disclosed in the drawings. In the drawings:

[0034] Figure 1 A cross-sectional view of the blood pump according to the present invention is shown.

[0035] Figure 2 It shows Figure 1 Magnified details of the blood pump.

[0036] Figure 3 A perspective view of the column of the drive unit is shown.

[0037] Figure 4 a to Figure 4 d shows a different view of another implementation of the column.

[0038] Figure 5 The arrangement includes six columns.

[0039] Figure 6 It shows Figure 5 The layout and back panel.

[0040] Figure 7 It shows Figure 6 The arrangement of the coil windings.

[0041] Figure 8 It shows Figure 7 The device and its housing.

[0042] Figure 9 a to Figure 9 c shows different views of the back panel.

[0043] Figure 10 a to Figure 10 c shows different views of the impeller's magnet.

[0044] Figure 11 Another implementation of the drive unit is shown.

[0045] Figure 12 Another implementation of the blood pump is shown.

[0046] Figure 13a and Figure 13b Different views of the drive unit and impeller magnet according to another embodiment are shown.

[0047] Figure 14a and Figure 14b The magnetic field lines between the magnets of the impeller are shown as an example.

[0048] Figure 15 A cross-sectional view of the drive unit and impeller magnet according to another embodiment is shown.

[0049] Figure 16 The operation of the drive unit is illustrated by way of example. Detailed Implementation

[0050] refer to Figure 1 The image shows a cross-sectional view of blood pump 1. Figure 2 An enlarged view of the interior of blood pump 1 is shown. Blood pump 1 includes a pump housing 2 with a blood inlet 21 and a blood outlet 22. Blood pump 1 is designed as an intravascular pump, also known as a catheter pump, and is configured into a patient's blood vessel by means of a catheter 25. The blood inlet 21 is located at the end of a flexible cannula 23, which can be placed through a heart valve such as the aortic valve during use. The blood outlet 22 is located in the side surface of the pump housing 2 and can be placed in a heart vessel such as the aorta. Blood pump 1 is connected to catheter 25, and an electrical wire 26 extends through catheter 25 to supply power to blood pump 1 to drive pump 1 by means of a drive unit 4, as described in more detail below.

[0051] Blood is transported along a channel 24 connecting a blood inlet 21 and a blood outlet 22 (blood flow is indicated by arrows). An impeller 3 is provided for transporting blood along the channel 24 and is mounted to be rotatable within the pump housing 2 about a rotation axis 10 by means of a first support 11 and a second support 12. The rotation axis 10 is preferably the longitudinal axis of the impeller 3. In this embodiment, both supports 11 and 12 are contact supports. However, at least one of supports 11 and 12 can be a non-contact support, such as a magnetic support or a hydrodynamic support. The first support 11 is a pivot support with a spherical support surface that allows rotational movement and a degree of pivoting movement. A pin 15 is provided, forming one of the support surfaces. The second support 12 is provided in a support member 13 to stabilize the rotation of the impeller 3, the support member 13 having at least one opening 14 for blood flow. Blades 31 are provided on the impeller 3 for transporting blood as the impeller 3 rotates. The rotation of the impeller 3 is caused by a drive unit 4, which is magnetically coupled to a magnet 32 ​​at the end of the impeller 3. The blood pump 1 shown is a hybrid blood pump with the main flow direction being axial. It should be understood that, depending on the arrangement of the impeller 3, and especially the arrangement of the blades 31, the blood pump 1 can also be a pure axial flow blood pump.

[0052] Figure 2 The internal structure of the blood pump 1 is shown in more detail, particularly the impeller 3 and the drive unit 4. The drive unit 4 includes multiple columns 40, such as six columns 40, wherein... Figure 2 Only two columns are visible in the cross-sectional view. Column 40 has a rod portion 41 and a head portion 42. The head portion 42 is disposed adjacent to the impeller 3 to magnetically couple the drive unit 4 to the impeller 3. For this purpose, the impeller 3 has a magnet 32, which in this embodiment is formed as a multi-piece magnet, as shown in the reference. Figure 10 a to Figure 10 c. A more detailed description is provided. Magnet 32 ​​is disposed at the end of impeller 3 facing drive unit 4. Column 40 is sequentially controlled by a control unit (not shown) to generate a rotating magnetic field for driving blood pump 1. Magnet 32 ​​is arranged to interact with the rotating magnetic field to cause impeller 3 to rotate about rotation axis 10. See below for further details. Figure 7 In more detail, the coil windings are arranged around the rod portion 41 of the post 40.

[0053] To close the magnetic flux path, the backplate 50 is located at the end of the rod portion 41 opposite to the head portion 42. The post 40 serves as the magnetic core and is made of a suitable material, such as steel or a suitable alloy, particularly cobalt steel. Similarly, the backplate 50 is made of a suitable magnetic material, such as cobalt steel. The backplate 50 enhances the magnetic flux, which allows for a reduction in the overall diameter of the blood pump 1, which is important for intravascular blood pumps. For the same purpose, the yoke 37, i.e., the additional backplate, is disposed in the impeller 3 on the side of the magnet 32 ​​opposite to the drive unit 4. In this embodiment, the yoke 37 has a tapered shape to guide the blood flow along the impeller 3. The yoke 37 may also be made of cobalt steel. One or more cleaning channels extending toward the central support may be formed in the yoke 37 or the magnet 32.

[0054] Figures 3 to 9 The details of drive unit 4 are shown in the image, while Figure 10 The magnet 32 ​​of the impeller 3 is shown. See also Figure 3 One of the pillars 40 is shown in a perspective view. In this embodiment, all pillars 40 in the assembly (i.e., six pillars 40) are identical. A pillar 40 includes a rod portion 41 and a head portion 42. The head portion 42 has an inclined surface 43, which in this embodiment forms an angle of 60° with respect to the longitudinal axis (i.e., an angle of 30° with respect to a plane perpendicular to the longitudinal axis). The rod portion 41 includes an end portion 44 opposite to the head portion 42, the end portion 44 having a reduced diameter to engage the back plate 50. In a plane perpendicular to the longitudinal axis, the head portion 42 has a larger cross-sectional dimension than the rod portion 41. The head portion 42 has a side surface 47, which is adjacent to the side surface of the adjacent pillar when assembled to form the drive unit 4. To avoid short-circuiting of magnetic flux between the pillars 40, small air gaps or other forms of isolation are provided between the head portions 42. To further avoid short circuits, it may be advantageous to provide an insulating material between the head portions 42 of the pillar 40 to retain the magnetic field within each of the pillars 40. In other words, the head portions 42 can be separated by a magnetically insulating material. For example, magnets, such as plates of magnetic material, can be arranged between the head portions 42 to separate the head portions 42 from each other, and to separate the corresponding magnetic fields from each other. The radially inner surface 48 of the head portion 42 of the column forms a central opening 54. It should be understood that the transition surface between surface 43 and surface 48 does not need to be circular.

[0055] Figure 4 The image shows a different view of another embodiment of the column 40, which corresponds to the aforementioned embodiment except for minor variations in the shape of the rod portion 41 and the head portion 42. Figure 4 a shows along Figure 4 The cross-sectional view of line AA shown in d, where Figure 4 d shows a top view of column 40 (i.e., towards head portion 42). Figure 4b shows a three-dimensional view of column 40, while Figure 4 c shows a bottom view (i.e., a view towards the end portion 44 of the rod portion 41). The column 40 may have a total length of approximately 9 mm to 10 mm, wherein the head portion 42 may have a length of approximately 2 mm. In this embodiment, the head portion 42 has a surface 43 that is inclined at an angle of 45° relative to the axis of rotation or longitudinal axis. Accordingly, Figure 4 The angle 45 between surface 43 and flange 49 shown in Figure a is 135°. When the post 40 is assembled in the housing, flange 49 can serve as a stop. Furthermore, shoulder 46 is formed through head portion 42, which can serve as a stop for the coil winding. (As shown in Figure a) Figure 3 The head portion 42 includes a side surface 47 and a radial inner surface 48.

[0056] Figure 5 It shows six combinations Figure 3 The assembly of the pillars 40. All pillars 40 are formed identically, such that each head portion 42 is formed as a 60° segment of a circle, that is, a 60° "fan-shaped block". It should be understood that the assembly may include fewer or more pillars, such as two, three, four, or five, or more than six, wherein the angle depends on the number of pillars, for example, four pillars all formed as 90° segments, or eight pillars all formed as 45° segments. As mentioned above, the number of pillars 40 is preferably even, wherein, for example, with respect to the control of the magnetic field, pillars 40 opposite each other in diameter can form a pair, i.e., each pair of pillars can be controlled as a unit to simultaneously activate the pillars in each corresponding pair. The head portion 42 forms a cone having a conical surface formed by an inclined surface 43. This is in Figure 6 This can be seen more clearly in the middle. Figure 6 In the middle, the end portion 44 with a reduced diameter of the rod portion 41 is installed in the back plate 50.

[0057] exist Figure 7 The same arrangement, including a coil winding 470 surrounding the post 40, is shown in the diagram. The coil winding 470 does not extend radially beyond the head portion 42, thus providing a compact external dimension. It should be understood that, preferably, the largest cross-sectional area defined by the head portion 42 is used for the coil winding 470 to optimize the use of available space and minimize air gaps that act as insulators and affect magnetic flux. Furthermore, the diameter of the rod portion 41 of the post 40 is chosen to optimize the number of windings in the coil winding 470. Figure 8A housing 60, to be mounted on a column assembly, is shown. The housing 60 conforms to the shape of the column assembly and includes a generally cylindrical portion 62 and a tapered end portion 61. The tapered end portion 61 tapers gradually at the same angle as the tapered surface formed by the inclined surface 43 of the head portion of the column; that is, this angle is preferably about 30° to 60°, more preferably 30° or 45°, relative to a plane perpendicular to the longitudinal axis. The housing 60 is closed by a back plate 50 at an open end 63 opposite to the tapered end portion 61. The tapered end portion 61 has a central opening 64, which is aligned with a central opening 54 formed by the column 40 and a central opening 53 in the back plate 50.

[0058] exist Figure 9 The back panel 50 is shown in more detail in different views. Figure 9 Top view in a Figure 9 The cross-sectional view along line AA in b, and Figure 9 (Cross-sectional view along line BB in c). The back plate 50 has holes 51 for receiving the reduced-diameter end portion 44 of the rod portion 41 of the post 40. Preferably, the number of holes 51 in the back plate 50 corresponds to the number of posts 40 in the drive unit 4. In the illustrated embodiment, six holes 51 are arranged at regular 60° intervals around the axis of rotation 10, and each of the holes 51 is equidistant from the axis of rotation 10. Figure 9 In the cross-sectional view of c, the hole 51 is shown extending completely through the back plate 50. However, the hole 51 can alternatively extend into the back plate 50 only to a certain depth, instead of completely penetrating the back plate 50. As described above, a central opening 53 is formed for receiving the support pin 15. The back plate 50 is made of a magnetic material to close the magnetic flux path; the magnetic material is preferably cobalt steel. The diameter of the back plate 50 can be approximately 5 mm to 7 mm. Furthermore, a notch 52 is provided at the periphery of the back plate 50 for receiving the wire 56 to connect the coil winding 470 to the control unit 55, such as by... Figure 9 The dashed line in b exemplarily illustrates the printed circuit board (PCB) on the back side of the back panel 50.

[0059] refer to Figure 10 The magnet 32 ​​of impeller 3 (see Figure 2 (Top view) Figure 10 a) Cross-sectional view ( Figure 10 b) and 3D diagram ( Figure 10 c) is shown. In this embodiment, six magnets 32 are provided, evenly arranged around the rotation axis 10, wherein the orientation of each magnetic field alternates. Fewer or more magnets can be provided, for example, four, eight, ten, or twelve magnets. The magnets 32 form recesses 35 having surfaces 33. The size and shape of the recesses 35 are as shown in the diagram. Figure 6The conical surface formed by the surface 43 of the head portion 42 of the column 40, as best shown in the diagram, corresponds to the housing 60 surrounding the drive unit 4, particularly the conical end portion 61. Figure 8 This should be taken into consideration. It should be understood that the distance between the impeller 3 and the drive unit 4 may not be constant, but may increase toward the axis of rotation 10 as explained above. The recess 35 in this embodiment has a tapered shape with an angle 34 of 45° relative to the axis of rotation 10 or the longitudinal axis. Depending on the shape of the drive unit 4, and particularly the shape of the end surface formed by the head portion 42 of the column 40, other angles such as 60° are also possible. Furthermore, the magnet 32 ​​is formed for receiving, such as Figure 2 The support pin 15 shown has a central opening 36. The central opening 36 is aligned with the central opening 54 of the drive unit 4. Figure 10 As shown in b, the magnetic flux of magnet 32 ​​is closed by yoke 37. Depending on the shape of impeller 3, yoke 37 can have any suitable shape, such as... Figure 2 The cone shape shown or such Figure 10 The disk shape is shown in b. Optionally, a package 38 is provided to encapsulate the magnet 32, and if applicable, the package 38 encapsulates the magnet 32 ​​and the yoke 37 to protect the magnet 32 ​​and the yoke 37 from corrosion.

[0060] Figure 11 Another embodiment of the drive unit is shown, which is generally similar to the aforementioned embodiment. The device includes six posts 40', each post 40' having a coil winding 470 on its rod portion 41'. As in the aforementioned embodiment, there may be fewer or more posts 40'. The posts 40' are preferably attached to a back plate (not shown) as in the aforementioned embodiment. Each post 40 includes a head portion 42', which has a different shape than the head portion 42 described above. Although the angle can be the same as described above, the inclined surface 43' faces radially inward rather than outward. That is, the head portion 42' forms a generally conical recess. It will be understood that the impeller magnet will be shaped accordingly, i.e., the magnet will have a corresponding conical shape instead of the conical recess as in the aforementioned embodiment. As in the aforementioned embodiment, the drive unit has a central opening 54'. Figure 11 In one embodiment, the posts 40' are separated by gaps 57', which prevent bypassing or short-circuiting between the posts 40', whereas in the previous embodiment, the head portions 42 of the posts 40 are shown as being adjacent to each other or separated only by small gaps. However, it should be understood that short-circuiting between posts should be avoided in all embodiments.

[0061] refer to Figure 12 This illustrates another embodiment of the blood pump 1, which is similar to... Figure 1 and Figure 2 Blood pump 1. Compared with the above embodiment, Figure 12 The blood pump 1 has an additional radial hydrodynamic support. The circumferential portion 28 of the pump housing 2 or sleeve is configured to form a gap 27 between the impeller 3 and the circumferential portion 28. In addition to the blood outlet 22, another blood outlet 29 allows blood to flow through the gap 27 and out of the pump housing 2. The size of the gap 27 is selected to form the radial hydrodynamic support.

[0062] Figure 13a and Figure 13b The impeller magnet 32 ​​and the magnet 32 ​​arranged relative to the drive unit 4 are illustrated exemplary. In this embodiment, four magnets 32 are provided, each separated by a gap 66. The gap 66, which can be formed as a channel between the surfaces 33 of the magnets 32, extends radially from the central opening 36 toward the outer periphery of the magnets 32. Reference will be made below. Figure 14a and Figure 14b To be more detailed, the reduction in the size of magnet 32 ​​does not result in a loss of magnetic coupling efficiency. Figure 13b The relative arrangement of magnet 32 ​​and drive unit 4 is shown, wherein a gap 65 is provided between magnet 32 ​​of drive unit 4 (i.e., stator) and impeller (i.e., rotor). Channels or gaps 66 improve the cleaning of gap 65 because they produce a centrifugal pump effect on the blood.

[0063] refer to Figure 14a and Figure 14b The principle of magnetic coupling between the rotor, particularly magnet 32, and the stator, i.e., drive unit 4, is illustrated by example. Figure 14a In this configuration, magnets 32 are not or substantially not separated by gaps. Some exemplary magnetic field lines from the North Pole (N) to the South Pole (S) are shown. Due to the gap 65 between the drive unit 4 and magnets 32, the innermost magnetic field lines do not interact with the drive unit 4. That is, this portion of the magnetic field does not contribute to the impeller's drive. Therefore, if a gap 66 is provided between magnets 32, the efficiency of magnetic coupling will not be lost. Figure 14b In, with Figure 14a The same amount of magnetic field lines reach the drive unit 4. As a technician who knows how to calculate the orientation of the magnetic field lines, the size of gap 66 is directly dependent on the size of gap 65.

[0064] refer to Figure 15 This illustrates another embodiment of a drive unit for a blood pump. The drive unit 4, including a column 40 with coil windings 470, is substantially the same as described above. The same reference numerals denote the same components. As in the aforementioned embodiment, the drive unit 4 includes a back plate 50. However, the impeller design is different. Figure 15Only the impeller magnet 32 ​​and yoke 37 are shown in the diagram. The impeller has an increased diameter, particularly larger than that of the drive unit 4, and an axial extension 39 that extends circumferentially around the drive unit 4, especially in the region of the head portion 42 of the column 40. This arrangement allows for improved magnetic coupling, as will be explained below.

[0065] As illustrated by some exemplary schematic magnetic field lines, the extension 39 causes magnetic coupling between the magnet 32 ​​and the drive unit 4 to occur not only in the region of the inclined surface 43, but also in the region of the outer surface of the head portion 42 of the column 40. In this region, the magnetic field lines extend in a generally radial direction between the rotor and stator of the blood pump and can generate high torque to drive the impeller. Similarly, as... Figure 15 As shown, as in all other embodiments, the magnetic field lines form a closed loop that extends through the post 40, which includes the head portion 42 and the rod portion 41, through the magnet 32, and through both the back plate 50 and the yoke 37.

[0066] Referring to Figure 13, the operation of the drive unit is exemplarily illustrated in an example with six columns 40a, 40b, 40c, 40d, 40e, and 40f. To generate a rotating magnetic field, the columns are controlled sequentially. These columns are controlled in pairs to establish balanced rotation of the impeller, with columns 40a and 40d, 40b and 40e, and 40c and 40f forming pairs respectively, opposite each other in diameter. The magnetic density can be increased by simultaneously activating four of the six columns. Figure 13 shows the sequence of three steps, with the activated columns labeled. In the first step, columns 40a, 40c, 40d, and 40f are activated; that is, current is supplied to the corresponding coil windings to generate a magnetic field. In the second step, columns 40a, 40b, 40d, and 40e are activated, and in the third step, columns 40b, 40c, 40e, and 40f are activated. This sequence is repeated to generate a rotating magnetic field.

Claims

1. A blood pump (1), comprising: - A pump housing (2) having a blood inlet (21) and a blood outlet (22). - An impeller (3), the impeller (3) being arranged in the pump housing (2) to be rotatable about a rotation axis (10), the impeller (3) having blades (31) the size and shape of which are designed to deliver blood from the blood inlet (21) to the blood outlet (22), and - A drive unit (4) for rotating the impeller (3), the drive unit (4) comprising a plurality of columns (40) arranged around the axis of rotation (10), each of the columns (40) comprising a rod portion (41) and a head portion (42) pointing toward the impeller (3), wherein coil windings (470) are arranged around the rod portion (41) of each of the columns (40), the coil windings (470) being sequentially controllable to generate a rotating magnetic field, wherein the impeller (3) comprises at least one magnet (32) arranged to interact with the rotating magnetic field to cause rotation of the impeller (3), wherein the drive unit (4) further comprises a back plate (50) engaging with the end (44) of the rod portion (41) of each column (40) opposite to the head portion (42). The head portion (42) of at least one of the columns (40) has a top surface (43) that is inclined at an angle relative to a plane perpendicular to the axis of rotation (10), and wherein the inclined top surfaces (43) of the head portions (42) of all the columns (40) having inclined top surfaces (43) together form a conical surface.

2. The blood pump according to claim 1, wherein the distance between the rotation axis (10) and the center of the column (40) having the inclined top surface (43) in the radial direction is less than or equal to the distance between the rotation axis (10) and the center of the cross-sectional area of ​​the rod portion (41) of the corresponding column (40) in the radial direction.

3. The blood pump according to claim 1 or 2, wherein the head portion (42) of the column (40) having the inclined top surface (43) has a generally triangular cross section along the plane including the axis of rotation (10).

4. The blood pump according to claim 1 or 2, wherein the at least one magnet (32) of the impeller (3) defines a conical recess (35) the size and shape of which correspond to the conical surface.

5. The blood pump according to claim 1 or 2, wherein the at least one magnet (32) of the impeller (3) has a surface (33) facing the head portion (42) of the at least one column (40) having the inclined top surface (43) and inclined at an angle (34) corresponding to the angle of the inclined top surface (43) of the head portion (42).

6. The blood pump according to claim 1 or 2, wherein the angle is from 0° to 90°.

7. The blood pump according to claim 1 or 2, wherein the impeller (3) comprises at least four of the magnets (32).

8. The blood pump according to claim 1 or 2, wherein the drive unit (4) comprises at least four of the columns (40).

9. The blood pump according to claim 1 or 2, wherein the head portion (42) of the column (40) having the inclined top surface (43) has a larger cross-sectional dimension in a plane perpendicular to the axis of rotation (10) than the corresponding rod portion (41).

10. The blood pump according to claim 1 or 2, wherein the back plate (50) includes a plurality of holes (51) arranged about the axis of rotation (10) and receiving the end (44) of the rod portion (41).

11. The blood pump according to claim 1 or 2, further comprising a housing (60) surrounding the drive unit (4), wherein the housing (60) is made of a non-magnetic and non-conductive material.

12. The blood pump according to claim 1 or 2, wherein the drive unit (4) has a central opening (54) extending along the axis of rotation (10).

13. The blood pump according to claim 1 or 2, wherein the drive unit (4) is disposed within the pump housing (2).

14. The blood pump according to claim 1 or 2, wherein the magnetic insulating material is disposed between the head portions (42) of adjacent columns (40).

15. The blood pump according to claim 6, wherein the angle is 30° to 60°.

16. The blood pump of claim 15, wherein the angle is 45°.

17. The blood pump according to claim 1 or 2, wherein the inclined top surface (43) faces outward in a radial direction.

18. The blood pump according to claim 7, wherein the impeller (3) comprises six or eight of the magnets (32).

19. The blood pump according to claim 7, wherein the at least four of the magnets (32) are separated by radially extending gaps (66).

20. The blood pump according to claim 8, wherein the drive unit (4) comprises six or eight of the columns (40).

21. The blood pump according to claim 9, wherein the corresponding coil winding (470) does not extend beyond the head portion (42) at least in the radial direction.

22. The blood pump of claim 11, wherein the non-magnetic and non-conductive material is aluminum.

23. The blood pump according to claim 12, wherein the central opening (54) is adapted to receive an elongated pin (15), wherein the axial end surface of the pin (15) forms a support surface of the impeller (3).

24. The blood pump according to claim 1 or 2, wherein the coil winding is embedded in a thermally conductive matrix, the thermally conductive matrix being non-conductive.

25. The blood pump according to claim 1 or 2, wherein the blood pump (1) is an intravascular blood pump (1) for insertion into a patient's blood vessels via the skin.

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