Magnetic levitation device and electromagnetic rotary drive

Abstract

To provide a magnetic levitation device with low eddy current losses.SOLUTION: A rotor 3 has a disk-shaped or ring-shaped magnetically effective core 31. A magnetic levitation device comprises a stator 2 with a cup-shaped recess such that the rotor can be inserted into the recess. The stator has a plurality of coil cores 25, each having a longitudinal leg 26 and a magnetic pole piece 27. Each longitudinal leg extends from a first end 261 in an axial direction A to a second end 262. A contact surface 271 is arranged at the second end. Each magnetic pole piece extends from the contact surface at least partially in a radial direction R to an end face 272. The radial direction R is perpendicular to the axial direction A. The end face is arranged around the cup-shaped recess. At least one concentrated winding 61 is arranged at each longitudinal leg. The longitudinal leg is made of a first material, and the magnetic pole piece is made of a second material, the first and second materials being different.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a magnetic levitation device according to the preambles of the independent claims and to an electromagnetic rotary drive comprising such a magnetic levitation device. [Background technology]

[0002] Magnetic bearing devices that magnetically support a rotor without contact have the advantage of not requiring a mechanical bearing for the rotor. The rotor is supported or stabilized by the magnetic force generated by the stator of the magnetic bearing device. Because of the absence of a mechanical bearing, such magnetic bearing devices are particularly suitable for pumping, mixing, centrifuging, or stirring devices that convey highly sensitive substances, such as blood pumps, or pumping, mixing, centrifuging, or stirring devices that make very high demands on purity, such as in the pharmaceutical or biotechnology industries, or pumping, mixing, centrifuging, or stirring devices that convey highly abrasive or corrosive substances that would very quickly destroy mechanical bearings, such as pumps or mixers for slurries, sulfuric acid, phosphoric acid, or other chemicals in the semiconductor industry.

[0003] Such magnetic bearing devices are used in the biotechnology industry, for example with bioreactors, e.g. in centrifugal pumps to transport fluids into or out of bioreactors or in mixing devices to mix fluids within bioreactors, etc. Such magnetic bearing devices are used in the semiconductor industry to transport highly erosive or abrasive materials, but also in rotating devices to spin wafers, for example.

[0004] It is also known to use magnetic bearing devices in viscometers.

[0005] An advantageous, per se known design of a magnetic bearing device is that of a temple structure, to which the present invention also relates.

[0006] A unique feature of the temple structure is that the stator of the magnetic bearing device includes multiple coil cores, each with a longitudinal leg extending axially from a first end to a second end. The axial direction here refers to the direction defined by the desired axis of rotation of the rotor supported by the magnetic bearing device. The desired axis of rotation is the axis around which the rotor rotates when in an operating state, centered and not tilted relative to the stator. In addition to the longitudinal legs, each coil core includes a transverse leg, also called a pole piece, which is located at the second end of the longitudinal leg and extends radially, usually inward, perpendicular to the axial direction. The transverse leg therefore extends substantially perpendicular to the longitudinal leg. Each coil core has an L-shape, with the transverse leg forming the shorter leg of the L. The supported rotor is therefore positioned between the transverse legs.

[0007] The structure's name comes from the fact that its axially extending longitudinal legs are reminiscent of temple columns.

[0008] One design of the stator of a magnetic bearing device includes, for example, six coil cores arranged circularly and evenly spaced around a cup-shaped recess into which the rotor can be inserted. The first ends of the longitudinal legs are typically circumferentially connected by back irons that act to conduct magnetic flux. The rotor to be supported includes a magnetically effective core, such as a permanent magnetic disk or ring, positioned between the radially inner ends of the transverse legs and rotates axially in an operating state, with the rotor magnetically supported without contact with the stator.

[0009] In such magnetic bearing devices, it is not necessarily true that the magnetically effective core of the rotor must be designed in a permanent magnet manner. Designs are also known in which the magnetically effective core of the rotor is designed in a non-permanent magnet manner, i.e. without permanent magnets. The magnetically effective core of the rotor is in this case, for example, designed in a ferromagnetic manner and is made, for example, of iron, nickel-iron, cobalt-iron, silicon-iron, mu-metal or another ferromagnetic material.

[0010] Furthermore, designs are possible in which the magnetically effective core of the rotor includes both ferromagnetic and permanent magnetic materials. For example, permanent magnets can be disposed or inserted within a ferromagnetic substrate. Such designs are advantageous, for example, when it is desired to reduce the cost of large rotors by conserving permanent magnetic material.

[0011] The longitudinal legs carry the windings, which generate the electromagnetic fields necessary to magnetically support the rotor without contact. The windings are designed so that, for example, one concentrated winding is wound around each longitudinal leg, i.e., the coil axis of each concentrated winding extends in the axial direction. Here, in a typical temple design, the coil axis of the concentrated windings extends in the axial direction and they are not located in the radial plane in which the rotor or its magnetically effective core is supported in operation.

[0012] In some designs, each longitudinal leg has exactly one concentrated winding. In other designs, each longitudinal leg has several, for example exactly two, concentrated windings. In other designs, windings are provided around two circumferentially adjacent longitudinal legs, so that both of these legs are located within the interior space of a concentrated winding.

[0013] The coil cores of magnetic bearing devices known from the state of the art are usually designed in sheet metal, whereby several metal sheets in the form of a coil core are stacked circumferentially and insulated from one another. The sheet metal design of the coil core prevents eddy currents due to the magnetic field extending in the direction of the metal sheets, i.e., following a longitudinal leg in the axial direction and a transverse leg in the radial direction.

[0014] Due to the magnetic fields emerging laterally, i.e. circumferentially, from the metal sheets of the longitudinal and lateral legs, the insulation of the metal sheets is ineffective, and therefore eddy currents still occur as these fields pass orthogonally through the metal sheets.

[0015] The magnetic gap is defined as the distance between the end faces of the pole pieces and the magnetically effective core of the rotor in the radial direction, and especially in magnetic bearing devices with large magnetic gaps, the orthogonal magnetic field components cannot be ignored and result in significant eddy current losses.

[0016] In the context of this application, a large magnetic gap means a magnetic gap that is greater than 1% of the diameter of the magnetically effective core in the radial direction. In some cases, the magnetic gap may be 5% or greater of the diameter of the magnetically effective core in the radial direction. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] European Patent Application No. 4084304 Summary of the Invention [Problem to be solved by the invention]

[0018] The object of the present invention is therefore to start from the state of the art and to propose a magnetic levitation device for contactless magnetic levitation of a rotor with a disk-shaped or ring-shaped magnetically effective core which has lower eddy current losses than the conventional state of the art.

[0019] Furthermore, the object of the present invention is to propose an electromagnetic rotary drive comprising such a magnetic levitation device. [Means for solving the problem]

[0020] The subject matter of the invention which meets this object is characterized by the features of the independent patent claims.

[0021] Thus, according to the present invention, there is provided a magnetic levitation device for contactless magnetic levitation of a rotor, the rotor having a disk-shaped or ring-shaped magnetically effective core, the magnetic levitation device having a stator with a cup-shaped recess, the recess being located at an axial end of the stator, into which the rotor can be inserted, the stator having a plurality of coil cores, each of the coil cores having a longitudinal leg and a pole piece, each longitudinal leg extending from a first axial end to a second axial end, and a contact surface at the second end. a rotor having a contact surface and a pole piece at least partially extending from the contact surface to an end surface in a radial direction, the radial direction being perpendicular to the axial direction, the end surface being arranged around a periphery of a cup-shaped recess; at least one concentrated winding arranged on each longitudinal leg, the concentrated winding surrounding each longitudinal leg; the longitudinal legs being formed from a first material; and the pole pieces being formed from a second material, the first material being different from the second material.

[0022] The magnetic pole pieces comprised by the magnetic levitation device according to the invention substantially correspond to the lateral legs of magnetic bearing devices or electromagnetic rotary drives in temple configurations (also known as temple motors) known from the state of the art.

[0023] The two-part embodiment of the coil core, where the pole pieces and the longitudinal legs are made of different materials, allows for the ideal material selection for both to reduce eddy current losses. By selecting different materials, it is possible to reduce eddy current losses where they are particularly high, which is usually the case for the pole pieces.

[0024] This means that the selection of the ideal material for the pole pieces will lead to a reduction in eddy current losses throughout the coil core. Therefore, the use of different materials provides a very flexible adaptability of the coil core to the corresponding requirements of the magnetic levitation device.

[0025] According to a preferred embodiment, each longitudinal leg is formed from a sheet metal element, which is stacked in the circumferential direction of the stator. The sheet metal embodiment ensures a reduction in eddy current losses in the longitudinal legs. Here, the stator defines a circumferential direction, and the coil cores are arranged in a ring shape along this direction.

[0026] Particularly in the case of such sheet metal embodiments, the selection of different materials for the longitudinal legs and pole pieces is advantageous for reducing eddy current losses where they are particularly high. Since the distance between adjacent pole pieces is particularly small, particularly at the ends of the cup-shaped recess, most eddy current losses occur in the pole pieces. This is because eddy current losses arise primarily from orthogonal magnetic fields, i.e., magnetic fields that penetrate the element in orthogonal directions. Such orthogonal magnetic fields have the potential to flow circumferentially from the pole piece of a first coil core to the pole piece of a second adjacent coil core, especially in the case of small distances between the pole pieces.

[0027] Thus, by suitable selection of the second material, which does not correspond to the material of the sheet metal elements of the longitudinal legs, an effective reduction of eddy current losses can be achieved where these occur most strongly.

[0028] It is also possible for the longitudinal legs to be made from a solid material.

[0029] In this process, the first material is preferably an electrical sheet metal. By common definition, an electrical sheet metal is understood to be a soft magnetic material for the magnetic core. Materials with low coercivity are usually called soft magnetic materials. Coercivity is the magnetic field strength required to demagnetize a material. Within the framework of this application, a soft magnetic material is understood to be a material with a coercivity, or more precisely, a magnetic polarization coercivity, of less than 2000 A / m.

[0030] There is also the possibility of using mu metal for the first material. If the longitudinal legs are made of a solid material, metals or metal compounds such as FeSi are preferred. It is also possible to design the pole pieces from sheet metal.

[0031] Furthermore, it is preferred that the second material is a powder composite, in particular a soft magnetic powder composite. These materials, known as "Soft Magnetic Composites (SMC)," can be high-purity iron powder with a special surface coating. In this case, the special surface coating is electrically insulating. SMCs are primarily known for their use in conducting high-frequency magnetic fields (frequencies>1 kHz). However, their use at lower frequencies is not yet common. Lower frequencies refer to frequencies greater than 65 Hz. Eddy current losses are only advantageous at magnetic field frequencies greater than 65 Hz.

[0032] A further advantage of soft magnetic powder composites is that they have an exceptional ability to conduct magnetic flux in three dimensions, have high electrical resistivity and high magnetic permeability, and therefore virtually no eddy current losses. It is precisely their ability to conduct magnetic flux in three dimensions without generating high eddy current losses that warrants their use as a second material.

[0033] Because soft magnetic powder composites have relatively high hysteresis losses, soft magnetic powder composites are used only to manufacture the pole pieces in preferred embodiments. In doing so, a balance is provided between reducing eddy current losses in locations where eddy current losses are particularly high and the undesirable effects of the powder composite on the magnetic circuit. Another reason for using powder composites only for the pole pieces is that powder composites are brittle sintered materials with essentially unknown aging processes, which can reduce the service life of the pole pieces and, therefore, the magnetic levitation device.

[0034] Of course, it is also possible for the longitudinal legs to be manufactured from a soft magnetic powder composite material while the pole pieces are formed from a different material.

[0035] The pole pieces can be attached to the longitudinal legs using several possible joining methods. These include, inter alia, force-locking joining methods such as clamping or crimping, form-locking joining methods such as screwing or bayonet fitting, or material-locking connections such as gluing. The connection between the longitudinal legs and the pole pieces can also be achieved via tongue-and-groove joints and / or plugs, such as pins, tines, or dovetail joints. In a preferred embodiment, the material-locking joining method is achieved by gluing. One advantage in this case is that the adhesive is in the same strength range as the powder composite material. Compared to clamps or screws, this has the advantage that no stress buildup occurs in the powder composite material. On the other hand, force-locking and form-locking joining methods have the advantage that they are less susceptible to defects caused, for example, by aging or errors during gluing.

[0036] In a preferred embodiment, the contact surface is designed in a flat manner and is arranged on the surface of a longitudinal leg extending perpendicular to the radial direction, where it is particularly preferred that the contact surface is arranged near the second end of the longitudinal leg.

[0037] In another preferred embodiment, the contact surface is arranged on the surface of a longitudinal leg extending perpendicular to the axial direction, and particularly preferably, the contact surface is arranged on the second end of the longitudinal leg in this case.

[0038] According to another preferred embodiment, the contact surface is designed in an angled manner, where angled can mean in this context that the contact surface is designed in an "L" shape, with one area of ​​the contact surface extending axially and one area extending radially.

[0039] With respect to material locking joining methods, this embodiment has a further advantage: Due to the angled embodiment of the contact surface, the available bonding surface is increased compared to non-angled embodiments of the contact surface.

[0040] Additionally, the tensile loads induced on the pole pieces by the magnetic forces are reduced by this embodiment.

[0041] According to a further preferred embodiment, the contact surface has two partial surfaces, a first partial surface extending perpendicular to the axial direction and a second partial surface extending perpendicular to the radial direction.

[0042] In a preferred embodiment, the pole piece is designed in an angled manner, and comprises two sections, one of which extends radially and the other extends axially.

[0043] In a preferred embodiment, the coil core has a rounded upper axial end, which turns the coil core from the axial direction to the radial direction. For example, in the case of an L-shaped coil core, in which the long part of the "L" is formed by the longitudinal legs and the short part of the "L" is formed by the pole pieces, the edges of the pole pieces that are radially outward when viewed from the cup-shaped recess and extend circumferentially in the radial plane are designed in a rounded manner. This embodiment has the advantage of having lower eddy current losses and is also easier to realize in terms of structure. This embodiment can be realized with all embodiments of the contact surfaces, end faces, and pole pieces or longitudinal legs.

[0044] In a preferred embodiment, the end faces of the pole pieces are designed as curved surfaces. It is particularly preferred that the curvature of the end faces is designed coaxially with the cup-shaped recess. In other words, the end faces of the pole pieces are segments of a cylindrical surface, the central axis of which coincides with the central axis of the cup-shaped recess and the radius of which is greater than that of the cup-shaped recess, so that the end faces do not protrude into the cup-shaped recess.

[0045] In a preferred embodiment, the end face is designed to be wider in the circumferential direction than the maximum extension of the contact surface in the circumferential direction. This means that the two edges of the end face extending in the circumferential direction are longer than one of the edges of the contact surface extending in the circumferential direction. If the end face is designed as a curved surface, the length of one of the arcs of the segment of the cylindrical surface in the radial plane is greater than the length of one of the edges of the contact surface extending in the circumferential direction.

[0046] This widening of the end surface in the circumferential direction has the advantage that it is beneficial for magnetic functionality, for example it can increase the passive stiffness and the active suspension.

[0047] According to a particularly preferred embodiment, the stator of the magnetic levitation device is designed to generate a torque that can magnetically drive the rotor to rotate about an axial direction without contact.

[0048] In this case, the stator is designed as a bearing and drive stator, both the stator of an electric drive and the stator of a magnetic levitation. The electrical windings of the stator can be used to generate a magnetic rotating field which, on the one hand, exerts a torque on the rotor which causes the rotor to rotate about the desired axis of rotation, and, on the other hand, exerts an optionally adjustable transverse force on the rotor so that the radial position of the rotor can be actively controlled or adjusted.

[0049] In particular, for embodiments where the magnetic levitation device is designed to generate torque, embodiments with wider end faces are advantageous because this is advantageous for magnetic function, such as being able to generate increased torque or to increase passive stiffness or active levitation force.

[0050] Furthermore, the present invention proposes an electromagnetic rotary drive designed as a temple motor, which comprises a magnetic levitation device according to the present invention and a rotor with a disk-shaped or ring-shaped magnetically effective core, the rotor being insertable into a cup-shaped recess, the rotor being designed as a rotor of an electromagnetic rotary drive.

[0051] Such electromagnetic rotary drives are known as bearingless motors, the term bearingless motor referring to electromagnetic rotary drives in which the rotor is entirely magnetically levitated with respect to the stator, with no separate magnetic bearings.

[0052] Further advantageous measures and embodiments of the invention are evident from the dependent claims.

[0053] In the following, the invention will be explained in more detail with reference to embodiments and with reference to the drawings. [Brief explanation of the drawings]

[0054] [Figure 1] 1 is a perspective view of an embodiment of a magnetic levitation device according to the present invention; [Figure 2] 2A and 2B are a perspective view and a plan view of one coil core of the magnetic levitation device of FIG. 1. [Figure 3] 1A-1C are schematic cross-sectional views of several embodiments of a coil core. [Figure 4] 3b) a perspective view of a first variant of the embodiment of the coil core, and FIG. 3c) a plan view thereof. [Figure 5] 3b) a perspective view of a second variant of the coil core embodiment, and its plan view. [Figure 6] 10 is a schematic cross-sectional view of a further embodiment of a coil core. [Figure 7] 7A and 7B are a perspective view and a plan view of a modified example of the coil core of FIG. 6. [Figure 8] 1 is a schematic cross-sectional view of a section of an embodiment of a coil core to illustrate the tensile forces acting thereon. [Figure 9] FIG. 10 is a perspective view of a further embodiment of a coil core. [Figure 10] 10 is a perspective view of a further embodiment of a magnetic levitation device according to the present invention. [Figure 11] 1 is a schematic cross-sectional view of an embodiment of a stator housing. [Figure 12] 1 shows a schematic cross-sectional view of a coil core known from the state of the art and its plan view; DETAILED DESCRIPTION OF THE INVENTION

[0055] FIG. 1 shows a perspective view of an embodiment of a magnetic levitation device according to the present invention, generally designated by reference numeral 1. The magnetic levitation device 1 is designed to magnetically levitate a rotor 3 having a disk-shaped or ring-shaped magnetically effective core 31 in a contactless manner. The magnetic levitation device 1 is designed according to a temple structure and includes a stator 2. Typically, the stator 2 includes a stator housing 21 (FIG. 11), which is not shown in FIG. 1 for clarity. A cup-shaped recess 211 (FIG. 11) is provided at one axial end of the stator housing 21 (FIG. 11), into which the rotor 3 can be inserted. The rotor 3 is designed to rotate about a desired axis of rotation, which defines an axial direction A. Typically, the central axis of the stator 2, which extends in the axial direction A, coincides with the desired axis of rotation. The desired axis of rotation refers to the axis about which the rotor 3 rotates in an operating condition when the rotor 3 is in a centered and non-tilted position relative to the stator 2, as shown in FIG.

[0056] The stator 2 has a plurality of coil cores 25, six in this case, each of the coil cores 25 having a longitudinal leg 26 and a pole piece 27. Each longitudinal leg 26 extends in the axial direction A from a first end 261 to a second end 262, with a contact surface 271 located at the second end 262, and each pole piece 27 extends at least partially in the radial direction R from the second end 262 to an end face 272, where the end face 272 faces the rotor 3 and is located around the periphery of the rotor 3. In other words, the pole pieces 27 of the coil cores 25 are arranged such that the end face 272 of the pole piece 27 is located around the periphery of the cup-shaped recess 211 (FIG. 11). The coil cores 25 of the stator 2 are equally spaced on a circular line so that the end faces 272 surround the magnetically active core 31 of the rotor 3 when the rotor 3 is inserted into the cup-shaped recess 211 (FIG. 11).

[0057] For ease of understanding, a perspective view and a plan view of one coil core 25 of the magnetic levitation device 1 of FIG. 1 are shown in FIG.

[0058] At least one concentrated winding 61 is arranged on each longitudinal leg 26, surrounding the respective longitudinal leg 26. In other embodiments, two or more concentrated windings may be arranged on a longitudinal leg 26. For example, there are embodiments in which exactly two concentrated windings are provided on each longitudinal leg 26, each concentrating winding surrounding its respective longitudinal leg 26, with two windings arranged on the same longitudinal leg 26 being arranged next to each other in the axial direction.

[0059] The concentrated windings 61 serve to generate an electromagnetic field that allows the rotor 3 to be magnetically levitated without contact in the cup-shaped recess 211 (FIG. 11).

[0060] In this embodiment, the longitudinal legs 26 are formed from sheet metal elements 263, which are stacked in the circumferential direction of the stator 2. The circumferential direction refers to a direction extending perpendicular to the radial direction R and perpendicular to the axial direction A. In this case, the longitudinal legs 26 are formed from a first material, in this case electrical sheet metal, and the pole pieces 27 are formed from a second material, which is a powder composite material, preferably a soft magnetic powder composite material. The first and second materials are therefore different.

[0061] It should be understood that the number of elements 263 in all embodiments and figures is purely exemplary, and there may be more or fewer than shown.

[0062] In this embodiment, the contact surface 271 is designed in an angled manner: it has two partial surfaces, a first partial surface 273 extending perpendicular to the axial direction and a second partial surface 274 extending perpendicular to the radial direction.

[0063] In this embodiment, the end face 272 of the pole piece 27 is designed as a curved surface. The curvature of the end face 272 is designed coaxially with the cup-shaped recess 211 (FIG. 11). In this case, the end face 272 is designed to be wider in the circumferential direction than the maximum extension of the contact surface 271 in the circumferential direction.

[0064] In other words, the end face 272 of the pole piece 27 is a segment of a cylindrical surface, and the central axis of this cylinder coincides with the central axis of the cup-shaped recess 211 (Figure 11), in this embodiment the axis of the axial direction A, and its radius is larger than that of the cup-shaped recess 211 (Figure 11), so that the end face 272 does not protrude into the cup-shaped recess 211 (Figure 11).

[0065] In a preferred embodiment, the end face 272 is designed to be wider in the circumferential direction than the maximum extension of the contact surface 271 in the circumferential direction. This means that the two edges 2721 or 2722 of the end face 272 extending in the circumferential direction are longer than one of the edges 2711 or 2712 of the contact surface 271 extending in the circumferential direction. If the end face 272 is designed as a curved surface, the length of one of the arcs 2721 or 2722 of the segment of the cylindrical surface in the radial plane E is greater than the length of one of the edges 2711 or 2712 of the contact surface 271 extending in the circumferential direction. The radial plane is indicated in FIG. 1 by a line in the radial direction R extending perpendicular to the axial direction A. The radial plane E is the plane that extends perpendicular to the axial direction A and contains the radial direction R. The radial plane E is the plane in which the magnetically active core 31 of the rotor 3 is actively magnetically levitated between the end faces 272 of the stator 2 in the operating state. When the rotor 3 is not tilted and not axially deflected, the magnetic mid-plane lies in the radial plane E. The radial plane E defines the xy plane of a Cartesian coordinate system, the z-axis of which extends in the axial direction A.

[0066] The radial position of the magnetically effective core 31 or rotor 3 refers to the position of the rotor 3 in the radial plane E.

[0067] According to a particularly preferred embodiment, the stator 2 is designed in such a way that, in addition to contactlessly magnetically levitating the rotor 3, it can also apply a torque to the rotor 3 or to the magnetically active core 31 of the rotor 3, which torque drives the rotor 3 to rotate about a desired axis of rotation. This means that in a preferred embodiment, the rotor 3 can be driven to rotate about an axial direction A.

[0068] The aforementioned circumferential extent of end face 272 has the advantage of being favorable for magnetic function, for example, it can increase passive stiffness and active levitation force, and in embodiments where magnetic levitation device 1 is designed to generate torque, it can also have the advantage of being able to generate increased torque.

[0069] The concentrated windings 61 therefore generate an electromagnetic rotating field in this embodiment that can both magnetically levitate the rotor 3 without contact relative to the stator 2 and drive it to rotate without contact about the axial direction A.

[0070] It should be understood that the number of six coil cores 25, while preferred, should be understood as merely an example. Of course, embodiments are possible in which the stator 2 includes fewer than six coil cores 25, such as five, four, or three coil cores 25, or in which the stator 2 includes more than six coil cores 25, such as seven, eight, or nine coil cores, or even an even greater number of coil cores 25.

[0071] The rotor 3 comprises a magnetically effective core 31 designed in the shape of a ring or a disk. The magnetically effective core 31 is designed as a ring according to the illustration in FIG. 1 and defines a magnetic central plane. The magnetically effective core 31 can alternatively be designed as a disk. Typically, in the case of a disk- or ring-shaped magnetically effective core 31, the magnetic central plane is the geometric central plane of the magnetically effective core 31 of the rotor 3, perpendicular to the axial direction A. In operation, the magnetically effective core 31 is suspended in a radial plane E extending perpendicular to the axial direction A.

[0072] Only the magnetically effective core 31 of the rotor 3 is shown in Figure 1, as this is sufficient for understanding the invention. It should be understood that the rotor 3 can of course also comprise further components such as a jacket or enclosure, preferably made of plastic, metal, alloy, or ceramic or ceramic material. The rotor 3 can also comprise vanes for mixing, stirring, or pumping fluids or other constituents.

[0073] When the rotor 3 is inserted into the cup-shaped recess 211 (FIG. 11), the rotor 3 and in particular the magnetically active core 31 of the rotor 3 is surrounded by the radially outwardly arranged end faces 272 of the pole pieces 27 of the coil core 25 of the stator 2. The pole pieces 27 therefore form a number of protruding stator poles, in this case six stator poles.

[0074] When the magnetically effective core 31 of the rotor 3 is in a desired position during operation, the magnetically effective core 31 is centered between the end faces 272 of the pole pieces 27. The concentrated windings 61 are shown disposed below the radial plane E and are aligned such that the coil axes of the concentrated windings extend in the axial direction A.

[0075] All first ends 261 of the longitudinal legs 26, i.e., the lower ends 261 according to the illustration (FIG. 1), are connected to one another by a back iron 28. The back iron 28 is preferably designed in a ring shape. An embodiment is possible in which the back iron 28 extends radially inward along all first ends 261 of the longitudinal legs 26 (see, for example, FIG. 1).

[0076] For magnetic levitation of the rotor 3 and optionally for generating the electromagnetic fields necessary for torque generation in the rotor 3, the longitudinal legs 26 of the coil core 25 carry windings designed as concentrated windings 61.

[0077] In operation, these electromagnetic rotating fields are generated by these concentrated windings 61 and can exert an arbitrarily adjustable transverse force in the radial direction on the rotor 3, thereby making it possible to actively control or adjust the radial position of the rotor 3, i.e. the position of the rotor 3 in the radial plane E perpendicular to the axial direction A. Optionally, a torque can additionally be generated in the rotor 3 by these electromagnetic rotating fields.

[0078] The "magnetically active core 31" of the rotor 3 refers to the region of the rotor 3 that magnetically cooperates with the stator 2 for the generation of magnetic levitation force, and optionally torque generation.

[0079] As already mentioned, in this embodiment, the magnetically effective core 31 is designed in the shape of a ring. The magnetically effective core 31 is further designed in a permanent magnetic manner. For this purpose, the magnetically effective core 31 can comprise at least one permanent magnet, but can also comprise several permanent magnets or, as in the embodiment described here, can consist entirely of a permanent magnetic material, so that the magnetically effective core 31 is a permanent magnet. The magnetically effective core 31 is, for example, radially magnetized.

[0080] These magnetically hard ferromagnetic or ferrimagnetic materials with high coercivity are usually called permanent magnets. Coercivity is the magnetic field strength required to demagnetize a material. Within the framework of this application, a permanent magnet is understood to be a component or material with a coercivity, or more precisely, the coercivity of the magnetic polarization, greater than 10,000 A / m.

[0081] Embodiments are also possible in which the magnetically active core 31 is designed in a permanent-magnet-free form, i.e. without permanent magnets. The rotor 3 is then designed, for example, as a reluctance rotor. The magnetically active core 31 of the rotor 3 is then made, for example, of a soft-magnetic material. Suitable soft-magnetic materials for the magnetically active core 31 are, for example, ferromagnetic or ferrimagnetic materials, i.e., in particular, iron, nickel-iron, cobalt-iron, silicon-iron, mu-metal.

[0082] Furthermore, embodiments are possible in which the magnetically effective core 31 of the rotor 3 comprises both ferromagnetic and permanent magnetic materials. For example, permanent magnets can be disposed or inserted within a ferromagnetic substrate. Such embodiments are advantageous, for example, when it is desired to reduce the cost of large rotors by saving on permanent magnetic material.

[0083] An embodiment is also possible in which the rotor is designed according to the squirrel cage rotor principle.

[0084] The stator 2 does not have any permanent magnets. In the framework of this application, the expression that the stator 2 "does not have any permanent magnets" should be understood to mean that the stator 2 does not include any permanent magnets that substantially contribute to a driving field for driving the rotation of the rotor 3 or for generating a magnetic levitation force for the rotor 3. Therefore, the magnetic flux generated by the stator 2 for driving and levitating the rotor 3 does not include any permanently magnetically excited magnetic flux.

[0085] Of course, it is possible for the rotor 3 and / or stator 2 to include other magnets or permanent magnets, for example in sensors that serve to capture the angular position of the rotor, or otherwise serve purposes unrelated to generating magnetic flux for driving and levitating the rotor 3.

[0086] The expression "having no permanent magnets" refers only to the generation of magnetic flux by the stator 2 to drive and levitate the rotor 3. In other words, the stator 2 has no permanent magnets that contribute to the magnetic flux by which the rotor 3 is driven and magnetically levitated.

[0087] However, it is also possible that the magnetic flux for driving and levitating the rotor 3 comprises a permanent magnetic flux, which is therefore generated by the rotor 3 itself, which is the case when the rotor 3 itself comprises permanent magnets.

[0088] The ring-shaped back iron 28 acts as a flux conducting element for conducting magnetic flux and can be made from a soft magnetic material.

[0089] Suitable soft magnetic materials for the back irons 28 are, for example, ferromagnetic or ferrimagnetic materials, i.e., in particular, iron, nickel-iron, cobalt-iron, silicon-iron, or mu-metal. In this case, a stator sheet metal stack design is preferred for the stator 2, where the back irons 28 are designed in sheet metal, i.e., the back irons 28 consist of a plurality of thin sheet metal elements stacked parallel to one another in the axial direction A. All back iron elements are similarly designed, i.e., in this case, substantially ring-shaped and each have the same thickness. Thus, the back irons 28 themselves are substantially ring-shaped and extend radially inward along the first ends 261 of the longitudinal legs 26 in the assembled state.

[0090] Embodiments are also contemplated in which so-called tape-wound toroidal cores are used as back irons 28. Such back irons 28 are shown in the embodiment of FIG. 10. They are coiled strips formed from electrical sheet metal. Preferably, grain-oriented electrical sheet metal is used here. In the state of the art, tape-wound toroidal cores are known primarily for use in transformers, voltage transformers, and inductors, but not for bearing devices, and especially not for electromagnetic rotary drives.

[0091] The back iron 28 can also consist of pressed and subsequently sintered grains of the aforementioned materials. The metal grains are preferably embedded in a plastic matrix so that they are at least partially insulated from one another, thereby minimizing eddy current losses. Therefore, soft magnetic composites consisting of electrically insulated, compressed metal particles are also suitable for the stator. In particular, these soft magnetic composites, also known as SMCs (Soft Magnetic Composites), can consist of iron powder grains coated with an electrically insulating layer. The SMC is then formed into the desired shape using a powder metallurgy process.

[0092] During operation of the magnetic levitation device 1, the magnetically effective core 31 of the rotor 3 cooperates with the stator 2 so that the rotor 3 can be magnetically levitated without contact with the stator 2 and preferably magnetically rotated about the axial direction A without contact. In this case, it is particularly advantageous that the same windings 61 by which the rotor 3 is magnetically levitated also serve to generate torque on the rotor 3. In this case, it is preferable to be able to actively adjust three degrees of freedom of the rotor 3, namely, its position and rotation in the radial plane E. The magnetically effective core 31 of the rotor 3 is passively magnetically stabilized by reluctance forces with respect to the axial deflection of the core 31 from the radial plane E in the axial direction A. That is, the axial deflection of the core cannot be controlled. The magnetically effective core 31 of the rotor 3 is also passively magnetically stabilized with respect to the remaining two degrees of freedom, namely, tilt with respect to the radial plane E perpendicular to the desired axis of rotation. The rotor 3 is therefore passively magnetically levitated or passively magnetically stabilized in the axial direction A and against tilt (three degrees of freedom in total) and actively magnetically levitated in the radial plane (two degrees of freedom) by cooperation of the magnetically active core 31 and the coil core 25.

[0093] Active magnetic levitation is also, as is common practice, referred to in the framework of this application as magnetic levitation that can be actively controlled or regulated, for example by means of an electromagnetic field generated by concentrated windings 61. Passive magnetic levitation or passive magnetic stabilization is that which cannot be controlled or regulated. Passive magnetic levitation or passive magnetic stabilization is based on a reluctance force that returns the rotor 3 to the desired position again, for example if the rotor 3 is deviated from the desired position, i.e. if the rotor is misaligned or offset in the axial direction A or if the rotor is tilted.

[0094] In magnetic levitation device 1, magnetic levitation and optionally the generation of torque acting on the rotor are achieved by an electromagnetic rotating field, as opposed to conventional magnetic bearings. On the one hand, to generate a combined magnetic levitation force and torque that rotates rotor 3 about axial direction A, it is possible to place just one concentrated winding 61 on each longitudinal leg 26, as shown in FIG.

[0095] On the other hand, embodiments are also possible in which two different winding systems are provided for the combined generation of the magnetic levitation force and the torque that rotates the rotor 3. For this purpose, for example, exactly two concentrated windings are arranged on each longitudinal leg 26, the concentrated windings being arranged next to each other in the axial direction A. One of these two windings belongs to the first of the two winding systems, and the other belongs to the second of the two winding systems.

[0096] 1, with just one concentrated winding 61 on each coil core 25, the current values ​​required for levitation and for torque generation, each determined in the control unit 40, are added or superimposed, e.g., using software, and the resulting total current is then applied to each concentrated winding 61.

[0097] If the stator 2 of the magnetic levitation device 1 according to the present invention is designed to generate torque, the magnetic levitation device 1 is suitable for an electromagnetic rotary drive designed as a temple motor. The magnetic levitation device 1 according to the present invention is also suitable for other devices such as centrifugal pumps, mixing devices for mixing flowable substances, e.g., stirring devices for mixing fluids in tanks, fans, or devices for supporting and rotating wafers, e.g., in semiconductor manufacturing.

[0098] FIG. 3 shows schematic cross-sectional views of several embodiments of the coil core 25.

[0099] 12 shows a schematic cross section and a plan view of a coil core 25' known from the state of the art. In this case, the coil core 25' is designed in one piece, with the longitudinal legs 26' and the pole pieces 27' forming a unit. In this case, the complete coil core 25' is formed from a sheet metal element 263'.

[0100] In all embodiments of the coil core 25 shown in FIG. 3, the longitudinal legs 26 should preferably be formed from sheet metal elements 263, which are stacked in the circumferential direction of the stator 2, the longitudinal legs 26 being formed from electrical sheet metal and the pole pieces 27 preferably being formed from a powder composite material, particularly preferably a soft magnetic powder composite material.

[0101] 3a) shows a further embodiment of the coil core 25, in which the contact surfaces 271 are designed in a flat manner and are arranged on the surfaces of the longitudinal legs 26 extending perpendicular to the radial direction. The pole pieces 27 are therefore arranged on the lateral sides of the longitudinal legs 26. In this variant, the pole pieces 27 are arranged on the upper second ends 262 of the longitudinal legs 26.

[0102] FIG. 3b) shows a further embodiment of the coil core 25, in which the contact surface 271 is designed in an angled manner. The contact surface 271 can thus be divided into two partial surfaces, the first partial surface 273 extending perpendicular to the axial direction and the second partial surface 274 extending perpendicular to the radial direction. The coil core 25 of FIG. 1 or 2 is included in this group of embodiments. In FIGS. 4 and 5, two further possible variants of this embodiment of the coil core 25 are shown.

[0103] 3c) shows a further embodiment of the coil core 25, in which the contact surfaces 271 extend perpendicular to the axial direction and are arranged on the surfaces of the longitudinal legs 26. The pole pieces 27 are therefore arranged on the surfaces of the longitudinal legs 26 at their upper second ends 262.

[0104] FIG. 3d) shows a further embodiment of the coil core 25, in which the contact surface 271 is again arranged on the surface of the longitudinal leg 26, which extends perpendicular to the axial direction. The pole piece 27 is therefore arranged on the surface of the second upper end of the longitudinal leg 26. A special feature of this embodiment is that the pole piece 27 is designed in an angled manner. This means that the pole piece 27 comprises two sections, one of which extends in the radial direction R and the other in the axial direction A. The pole piece 27 therefore has an "L" shape. The two sections of the pole piece 27 do not necessarily have to have the same edge length. It is also possible for one section to have a longer edge length than the other. Likewise, the angle between the two sections is not necessarily 90°. Embodiments in which the two sections form an angle other than 90° are also possible.

[0105] 4 shows a perspective view (top view) of a first variant of the coil core 25 of FIG. 3b) and its plan view (bottom view) in an axial direction, i.e., from above. In this variant, the end faces 272 are designed as flat surfaces without curvature. In this variant, the longitudinal legs 26 are formed from sheet metal elements 263, the material of which is preferably electrical sheet metal. The pole pieces 27 are formed from a powder composite material, preferably a soft magnetic powder composite material.

[0106] 5 shows a perspective view (top view) of a second variant of the embodiment of the coil core 25 of FIG. 3b) and its plan view (bottom view) in an axial, i.e., top view. In this variant, the end faces 272 of the pole pieces 27 are designed as curved surfaces. The curvature of the end faces 272 is designed coaxially with the cup-shaped recesses 211 (FIG. 11). In this variant, the end faces 272 are designed in the circumferential direction to be no wider than the maximum extension of the contact surfaces 271 in the circumferential direction. This means that the edges 2711 form angles of 90° with the two side edges 2713 of the pole pieces 27, respectively.

[0107] 2 to 5 can of course also be combined with one another in any way, which means that, for example, in each of the embodiments of the coil core 25 of Fig. 3, the end faces 272 of the pole pieces 27 can be designed as curved surfaces or, for example, the end faces 272 can be designed wider in the circumferential direction than the maximum extension of the contact surfaces 271 in the circumferential direction.

[0108] FIG. 6 shows a schematic cross-sectional view of a further embodiment of the coil core 25. In this case, the coil core 25 has a radius at its upper axial end 252, which redirects the coil core 25 from the axial direction A to the radial direction R. In this embodiment, the coil core 25 and the contact surface 271 are designed according to an embodiment similar to FIG. 3b), but the coil core 25 additionally has a radius 257 at its outer edge 258 at its upper axial end 252. This means that in this embodiment, compared to the embodiment in FIG. 3, the outer radial edge 258 at the upper axial end 252 of the coil core 25 is a broken or rounded edge, as indicated by the radius 257. Depending on the embodiment of the coil core 25, the radius 257 can extend only in the region of the longitudinal legs 26, only in the region of the pole pieces 27, or both in the region of the longitudinal legs 26 and the pole pieces 27.

[0109] This embodiment has the advantage of having lower eddy current losses and is also easier to realize in terms of construction. Of course, this embodiment can be realized or combined with all other embodiments of the coil core 25 in terms of the contact surfaces 271, the end faces 272, the pole pieces 27 and the longitudinal legs 26.

[0110] With regard to the structure and materials of the longitudinal legs 26 and pole pieces 27, the same advantages as in the embodiment of the coil core 25 described in FIG. 3 are important.

[0111] Figure 7 shows a perspective view (top view) and a plan view (bottom view) of a variant of the embodiment of the coil core 25 of Figure 6, depicted axially, i.e. from above. In this variant, the end faces 272 of the pole pieces 27 are designed as curved surfaces, the curvature of which is designed coaxially with respect to the cup-shaped recess 211 (Figure 11).

[0112] Likewise, a variant is possible in which the end face 272 of the pole piece 27 is designed to be wider in the circumferential direction than the maximum extension in the circumferential direction of the contact surface 271. Furthermore, the end face 272 may not have any curvature and may simply be flat.

[0113] FIG. 8 shows a schematic cross-sectional view of a section of an embodiment of the coil core 25 to illustrate the pulling forces acting thereon. This diagram serves only to illustrate the magnetic pulling forces acting on an embodiment of the coil core 25 similar to FIG. 3b. The four thick arrows, labeled F1-F4, symbolize the force vectors acting on the respective surfaces. Because the rotor 3 has a magnetically active core 31, the rotor 3 is attracted to the coil core 25, and more precisely, to the pole pieces 27. Because this attraction is reciprocal, an equal and opposite force must exist so that the rotor 3 can be levitated in the magnetic levitation device 1. This means that a force also acts on the pole pieces 27. The force acting on the pole pieces 27 is transmitted via the pole pieces 27 to the longitudinal legs 26 and thus to the contact surfaces 271. Depending on how the contact surfaces 271 are designed, different force vectors act on the contact surfaces 271. In the case of a non-angled contact surface 271 (see FIGS. 3a and 3c), the force acts only in either the axial direction A or the radial direction R, depending on the embodiment. This means that the entire force acting on the contact surface 271 is transmitted only to the longitudinal leg 26 by one force vector. As a result, the requirements for the joining method in these two examples are very high in order to be able to form a stable and reliable connection between the pole piece 27 and the longitudinal leg 26 at the contact surface 271. For this reason, it is advantageous to optimize the contact surface 271, as shown in FIG. 8, so that it is designed in an angled manner. In this embodiment, the force acting on the contact surface 271 is divided into two forces F2 and F4. This means that both a force vector in the axial direction A and a force vector in the radial direction R act on the longitudinal leg 26. This means that only very low loads due to magnetic forces act on the contact surface 271, thereby reducing the likelihood of defects in the coil core 25.

[0114] A further advantage resulting from this is that more cost-effective joining methods can be used for a stable and reliable connection between the pole piece 27 and the longitudinal leg 26. With respect to material locking joining methods, this embodiment has a further advantage: due to the angled contact surface 271, the available bonding surface is increased compared to non-angled embodiments of the contact surface 271, which allows for a stable and reliable connection between the pole piece 27 and the longitudinal leg 26.

[0115] FIG. 9 is a perspective view of a further embodiment of the coil core 25. In this case, the longitudinal legs 26 are again formed from sheet metal elements 263, which are stacked in the circumferential direction of the stator 2. Each coil core 25 has a first transverse boundary surface 255 and a second transverse boundary surface 256. The pole pieces 27 have a curvature of the end surface 272 that is coaxial with the cup-shaped recess 211 (FIG. 11). In the circumferential direction, the end surface 272 is designed to be wider than the maximum extension of the contact surface 271 in the circumferential direction. In this embodiment, the pole pieces 27 are made of a powder composite material, preferably a soft magnetic powder composite material. However, the pole pieces 27 can also be made of a different material. The contact surface 271 is designed in an L-shape, and the coil core 25 has a rounded axial upper end 252 that turns the coil core 25 from the axial direction A to the radial direction R. In this embodiment, at least one of the first or second lateral boundary surfaces 255, 256 has three slots 254. However, other embodiments are possible in which there are two or fewer or four or more slots 254. Slots 254 may not only extend through the two lateral boundary surfaces 255, 256, but may also be present in the inner element 263. Embodiments are possible in which multiple slots 254 penetrate all of the elements 263.

[0116] In this embodiment, the advantage is that the slots 254 are electrically insulating, thereby blocking the passage of eddy currents. By this measure, eddy current losses are also significantly reduced.

[0117] Figure 10 is a perspective view of a further embodiment of a magnetic levitation device 1 according to the present invention. In the following description of the further embodiment of the magnetic levitation device 1, only the differences from the first embodiment of Figure 1 will be described in more detail. The description of the first embodiment applies equally or similarly to the second embodiment. The same reference symbols indicate the same or functionally equivalent features described with respect to the first embodiment.

[0118] In this embodiment of FIG. 10, the magnetic levitation device 1 includes the coil core 25 shown in FIG. 9. A further difference between this embodiment of the magnetic levitation device 1 and the embodiment of FIG. 1 is the different design of the back iron 28. The back iron 28 is designed in a ring shape with a metal strip 29 extending from a radially inner starting point 291 to a radially outer end 292. The strip 29 forms a plurality of strip turns 293 that are flush with each other in the radial direction R. The longitudinal legs 26 are bounded at their first ends 261 by axial end faces 265 against which the back iron 28 abuts. The back iron 28 forms a circular ring, and the radial width of the ring is equal to the radial width of the end faces 265 of the longitudinal legs 26. This means that the radially inner starting point 291 is flush with the radially inner surface 266 of the longitudinal leg 26 in the axial direction A, and the radially outer end 292 is flush with the radially outer surface 267 of the longitudinal leg 26 in the axial direction A.

[0119] In particular, this has the advantage that there is more space within the stator 2 that can be used to mount other components. By doing so, the stator 2, together with the stator housing 21 (FIG. 11), can be made smaller and more compact, which increases the flexibility of use of the magnetic levitation device 1.

[0120] Needless to say, all embodiments of the coil core 25 shown in the description of the drawings can be combined in any manner with their respective features, and likewise, all embodiments of the coil core 25 can be used in the embodiments of the magnetic levitation device 1.

[0121] Furthermore, all of the illustrated embodiments of the coil core 25 can be designed in such a way that the space available for the rotor 3 in the magnetic levitation device 1 is increased. This is achieved by a special geometry of the coil core 25.

[0122] In the process, the coil core 25 is divided into an axially lower section and an axially upper section, which are arranged next to each other in the axial direction A. The pole pieces 27 are arranged in the axially upper section. For each coil core 25, the end face 272 of the pole piece 27 has a first radial distance from the axially lower section of the associated longitudinal leg 26 and a second radial distance from the axially upper section, the second distance being greater than the first distance. This means that each longitudinal leg 26 is designed such that the axially upper section is radially offset outward relative to the axially lower section, thereby increasing the space available for the rotor 3 between the end faces 272 without the risk of direct transmission of magnetic flux between the longitudinal leg 26 and the magnetically effective core 31 of the rotor 3. Due to the axially upper section being radially offset outward relative to the axially lower section, the distance between the longitudinal legs 26 and the end faces 272, i.e. the second distance, increases in the region of the axially upper section, thereby also increasing the distance between the magnetically effective core 31 of the rotor 3 and the longitudinal legs 26, particularly in the region of the axially upper section.

[0123] Such a coil core 25 as just described is designed similarly to the coil core shown in FIG. 3 of European Patent Application No. 4084304.

[0124] Figure 11 shows a schematic cross-sectional view of an embodiment of the stator housing 21. In the embodiments of Figures 1 and 10, this stator housing 21 is not shown for the sake of clarity. Figure 11 is intended only to serve as an illustration to show what the internal enclosure of the stator 2 required for operation of the magnetic levitation device 1 might look like. For this reason, the other components of the stator 2 are shown only diagrammatically and should be understood as merely illustrative.

[0125] An embodiment of the stator housing 21 is also possible in which the cup-shaped recess 211 opens at its center into a bore that extends axially A along the central axis of the stator 2 and through the entire stator housing 21 .

[0126] For example, during operation of the magnetic levitation device 1 in areas where chemically corrosive substances are used, it is important to ensure that the interior of the stator 2 is sealed and thereby protected from these substances. To ensure that the rotor 3 can still be used, the stator housing 21 has a cup-shaped recess 211 into which the rotor 3 can be inserted.

Claims

1. A magnetic levitation device for contactless magnetic levitation of a rotor (3), the rotor (3) having a disk-shaped or ring-shaped magnetically effective core (31), the magnetic levitation device having a stator (2) with a cup-shaped recess (211), the recess (211) being arranged at an axial end of the stator (2), into which the rotor (3) can be inserted, the stator (2) having a plurality of coil cores (25), each of the coil cores (25) having a longitudinal leg (26) and a magnetic pole piece (27), each of the longitudinal legs (26) extending from a first end (261) to a second end (262) in an axial direction (A), a contact surface (271) being arranged at the second end (262), a magnetic levitation device for contactless magnetic levitation of a rotor (3), wherein each of the pole pieces (27) extends at least partially from the contact surface (271) to an end surface (272) in a radial direction (R), the radial direction (R) being perpendicular to the axial direction (A), the end surface (272) being arranged around the cup-shaped recess (211), and at least one concentrated winding (61) is arranged on each of the longitudinal legs (26), the concentrated winding surrounding each of the longitudinal legs (26), wherein the longitudinal legs (26) are made of a first material and the pole pieces (27) are made of a second material, the first material and the second material being different.

2. 2. The magnetic levitation device of claim 1, wherein each of the longitudinal legs (26) is formed from an element (263) of sheet metal, the elements (263) being stacked in the circumferential direction of the stator (2).

3. The magnetic levitation device of claim 1 or 2, wherein the first material is an electrical metal sheet.

4. 4. The magnetic levitation device according to claim 1, wherein the second material is a powder composite, preferably a soft magnetic powder composite.

5. 5. A magnetic levitation device according to claim 1, wherein the contact surface (271) is designed in a flat manner and is arranged on a surface of the longitudinal leg (26) extending perpendicular to the radial direction.

6. 5. The magnetic levitation device according to claim 1, wherein the contact surface (271) is arranged on a surface of the longitudinal leg (26) extending perpendicular to the axial direction.

7. 7. The magnetic levitation device according to any one of claims 1 to 6, wherein the contact surface (271) is designed in an angled manner.

8. 8. The magnetic levitation device of claim 7, wherein the contact surface (271) has two partial surfaces, a first partial surface (273) extending perpendicular to the axial direction and a second partial surface (274) extending perpendicular to the radial direction.

9. 9. A magnetic levitation device according to any one of claims 1 to 8, wherein the pole piece (27) is designed in an angled manner and comprises two partial pieces, one of which extends in the radial direction and the other of which extends in the axial direction.

10. 10. The magnetic levitation device of claim 1, wherein the coil core (25) has a radius at its axial upper end (252), the radius redirecting the coil core (25) from the axial direction (A) to the radial direction (R).

11. 11. The magnetic levitation device according to any one of the preceding claims, wherein the end faces (272) of the pole pieces (27) are designed as curved surfaces.

12. The magnetic levitation device according to claim 10, wherein the curvature of the end face (272) is designed coaxially with the cup-shaped recess (211).

13. 13. A magnetic levitation device according to any one of claims 1 to 12, wherein the end faces (272) are designed wider in the circumferential direction than the maximum extension of the contact surfaces (271) in the circumferential direction.

14. 14. The magnetic levitation device according to any one of claims 1 to 13, wherein the stator (2) is designed to generate a torque by which the rotor (3) can be magnetically driven without contact to rotate about the axial direction (A).

15. 15. An electromagnetic rotary drive designed as a temple motor, comprising a magnetic levitation device (1) according to claim 14 and a rotor (3) with a disk-shaped or ring-shaped magnetically effective core (31), wherein the rotor (3) can be inserted into the cup-shaped recess (211), and the rotor (3) is designed as the rotor (3) of the electromagnetic rotary drive.

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