Magnetic suspension device and electromagnetic rotary driver

Abstract

The invention relates to a magnetic levitation device for contactless magnetic levitation of a rotor, the rotor comprising a disc-shaped or annular magnetic active core, the magnetic levitation device having a stator comprising a plurality of coil cores, each of the plurality of coil cores includes a longitudinal leg extending in an axial direction from a first end to a second end, at which a back iron connecting the first ends of all the longitudinal legs is arranged, and a transverse leg arranged at the second end of the longitudinal leg and extending in a radial direction perpendicular to the axial direction. Wherein each longitudinal leg is provided with at least one concentrated winding surrounding the respective longitudinal leg, the stator has a cup-shaped recess into which the rotor can be inserted, the cup-shaped recess is arranged at an axial end of the stator, the transverse legs are arranged around the cup-shaped recess, the stator comprises a shield extending in a circumferential direction along a plurality of coil cores, and the shield is arranged around the rotor. The shield extends in an axial direction from a shield first end to a shield second end. An electromagnetic rotary drive having such a magnetic suspension device.

Description

TECHNICAL FIELD

[0001] The invention relates to a magnetic suspension device according to the preamble of the independent patent claim and to an electromagnetic rotary drive having such a magnetic suspension device. BACKGROUND

[0002] Magnetic bearing devices for contactless magnetic bearings of a rotor have the advantage that they do not require mechanical bearings for the rotor. The rotor is supported or stabilized by means of magnetic forces generated by the stator of the magnetic bearing device. Since there are no mechanical bearings, such magnetic bearing devices are particularly suitable for pumping, mixing, centrifugal or stirring devices with which very sensitive substances are conveyed, such as blood pumps, or for which there are very high demands with regard to purity, such as in the pharmaceutical industry or in the biotechnology industry, or with which abrasive or erosive substances are conveyed which would very quickly destroy mechanical bearings, such as pumps or mixers for slurry, sulfuric acid, phosphoric acid or other chemicals in the semiconductor industry.

[0003] In the biotechnology industry, such magnetic bearing devices are used, for example, in connection with bioreactors, for example in centrifugal pumps for conveying fluids into or out of a bioreactor, or in mixing devices for mixing fluids in a bioreactor. In the semiconductor industry, such magnetic bearing devices are used not only for conveying erosive or abrasive substances, but also for rotary devices with which, for example, wafers are rotated.

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

[0005] An advantageous design of magnetic bearing devices known per se is a design in the form of a temple, to which the invention also relates.

[0006] The temple is characterized in that the stator of the magnetic bearing device has a plurality of coil cores, each of which comprises a longitudinal leg extending in an axial direction from a first end to a second end. Here, the axial direction is the direction defined by the desired rotational axis of the rotor supported by the magnetic bearing device. The desired rotational axis is the rotational axis about which the rotor rotates in the operating state in its centered and non-inclined position relative to the stator. In addition to the longitudinal leg, each coil core also comprises a transverse leg, which is arranged at the second end of the longitudinal leg in each case and which extends in a radial direction, usually towards the inside, wherein the radial direction is perpendicular to the axial direction. The transverse leg thus extends essentially at a right angle to the longitudinal leg. The coil cores each have the shape of an L, wherein the transverse leg forms the short leg of the L. The rotor to be supported is then arranged between the transverse legs.

[0007] The plurality of longitudinal legs, which extend in the axial direction and remind one of the columns of a temple, give the construction its name.

[0008] In one design, the stator of the magnetic bearing device has, for example, six coil cores, which are arranged circularly and equidistantly around a cup-shaped recess into which the rotor can be inserted. The first end portions of the longitudinal legs are usually connected in the circumferential direction by a back iron for conducting the magnetic flux. The rotor to be supported comprises a magnetically effective core, for example a permanent-magnet disk or a permanent-magnet ring, which is arranged between the end portions positioned radially inside the transverse legs and, in the operating state, rotates around the axial direction, wherein the rotor is contactlessly magnetically supported with respect to the stator.

[0009] For such magnetic bearing devices, it is not necessarily the case that the magnetically effective core of the rotor must be designed in a permanent-magnetic manner. Designs are also known in which the magnetically effective core of the rotor is designed in a non-permanent-magnetic manner, i.e. without permanent magnets. The magnetically effective core of the rotor is then designed, for example, 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 comprises both ferromagnetic material and permanent-magnetic material. For example, permanent magnets can be placed or inserted into a ferromagnetic matrix. Such a design is advantageous, for example, if one wishes to reduce the costs of a large rotor by saving permanent-magnetic material.

[0011] The longitudinal legs carry windings in order to generate the electromagnetic fields necessary for the contactless magnetic bearing of the rotor. For example, the windings are designed such that one concentrated winding is wound around each longitudinal leg, i.e. the coil axis of each concentrated winding extends in each case in the axial direction. Here, it is typical for the temple-like construction that the coil axis of the concentrated winding extends in the axial direction and that the concentrated winding is not arranged in the radial plane in which the rotor or the magnetically effective core of the rotor is supported in the operating state.

[0012] Designs are possible in which exactly one concentrated winding is arranged on each longitudinal leg. In other designs, several, for example exactly two, concentrated windings are provided on each longitudinal leg. Designs are also possible in which windings are provided which are wound around two longitudinal legs adjacent in the circumferential direction such that both of the two adjacent longitudinal legs are located in the inner space of the concentrated winding.

[0013] The stators of the magnetic bearing arrangement are encapsulated in a stator housing, so that they can withstand the harsh conditions of the application fields mentioned at the outset. For example, the stator housings known from the state of the art are mostly made of aluminum to ensure good heat dissipation from the windings. Housings are known which comprise cooling fins to improve the heat dissipation in this way. It is also known to protect the housing more robustly from external influences such as aggressive chemicals using a coating.

[0014] The use of aluminum as a stator housing is desirable because it has good thermal conductivity in order to achieve good heat dissipation from the stator. However, the use of aluminum also has disadvantages. The aluminum housing not only conducts heat well, but also conducts electricity well. This causes eddy currents to be generated in the stator housing. The windings of the stator not only generate magnetic fields inside the stator, i.e. towards the central axis of the stator, for the bearing and drive of the rotor, but also generate magnetic fields which extend outside the stator. These magnetic fields penetrate the aluminum housing, which conducts electricity well. During operation of the magnetic bearing arrangement, eddy currents are then generated in the housing, which cause significant losses and generate heat in the housing, whereby the motor is also heated internally. SUMMARY

[0015] It was therefore the object of the present invention, starting from this state of the art, to propose a magnetic levitation arrangement for the contactless magnetic levitation of a rotor having a disc-shaped or ring-shaped magnetically effective core, which has lower eddy current losses than the prior art and at the same time ensures effective heat dissipation.

[0016] Furthermore, it was the object of the present invention to propose an electromagnetic rotary drive having such a magnetic levitation arrangement.

[0017] The subject matter of the present invention which fulfills this object is characterized by the features of the independent patent claims.

[0018] According to the invention, therefore, a magnetic suspension device for contactless magnetic suspension of a rotor comprising a disc-shaped or ring-shaped magnetically effective core is proposed, wherein the magnetic suspension device has a stator having a stator housing, which stator comprises a plurality of coil cores, each of which comprises a longitudinal leg extending in an axial direction from a first end to a second end and a transverse leg arranged at the second end of the longitudinal leg and extending in a radial direction perpendicular to the axial direction, wherein a back iron is arranged at the first end, which back iron connects the first ends of all longitudinal legs, wherein at least one concentrated winding is provided on each longitudinal leg, which surrounds the respective longitudinal leg, wherein the stator further has a cup-shaped recess into which the rotor can be inserted, wherein the cup-shaped recess is arranged at an axial end of the stator, and wherein the transverse legs are arranged around the cup-shaped recess. The stator comprises a shield, which extends in a circumferential direction along the plurality of coil cores, wherein the shield extends in the axial direction from a shield first end to a shield second end.

[0019] By using the shield, it is prevented that the magnetic field can escape from the stator to the outside, i.e. from the stator housing. The magnetic field no longer penetrates the stator housing, but is conducted inside the stator housing, which leads to a reduction of eddy current losses.

[0020] A further advantage of using the shield in the interior of the stator housing is that the stator housing can still be made of a well-conducting material, such as aluminum. As a result, the dissipation of heat generated during operation of the stator reliably works.

[0021] The shield extends radially outward in the circumferential direction along the plurality of coil cores. The shield can be open in the circumferential direction, i.e. the shield extends only along the plurality of coil cores, or closed, i.e. the shield extends along all coil cores. Embodiments are also possible in which notches are provided in the shield. For example, these notches can be provided for the feedthrough of connectors through the shield, such as cables.

[0022] According to a preferred embodiment, the shield is arranged radially outward around the coil cores and extends over an angle of at least 120 degrees, preferably at least 240 degrees, in the circumferential direction.

[0023] According to a preferred embodiment, the shield is designed in an annular manner.

[0024] Due to the configuration of the stator, it is advantageous to use a shield designed in an annular manner. However, it is also possible that the shield is designed in a polygonal manner, for example hexagonal or octagonal. The design of the shield can be individually adapted to the shape and / or their arrangement of the corresponding stator or of the corresponding coil cores.

[0025] In a preferred embodiment, the shield comprises at least two shield segments, each of which extends in a circumferential direction from a segment first end to a segment second end.

[0026] Furthermore, it is preferred that the shield segments are arranged next to each other in a circumferential direction. Embodiments in which the shield segments are arranged next to each other in an axial direction are also possible.

[0027] In this context, being arranged next to each other includes a distance between the shield segments as well as their abutting contact and their overlap.

[0028] According to another preferred embodiment, the shield is designed as a strip, wherein the strip forms several strip windings, which lie against each other in relation to the radial direction and are particularly preferably insulated from each other.

[0029] Here, the strip can be made of an electrical metal sheet, preferably of a grain-oriented electrical metal sheet. According to the general definition, an electrical metal sheet is understood to be a soft-magnetic material for magnetic cores. There is also the possibility of using μ-metal as a material for the strip.

[0030] Here, the advantage is that such strips are frequently used in technology and are therefore cost-effective. It is also advantageous that the strip can be produced relatively easily and that it is possible to directly insulate the strip windings from each other during production.

[0031] Furthermore, according to another preferred embodiment, it is preferred that the shield first end is arranged at the same height as the winding first end with respect to the axial direction.

[0032] In the case of exactly one winding being arranged at the longitudinal leg, the winding first end refers to the end of this winding which is positioned closer to the first end of the longitudinal leg in the axial direction. If the winding second end is arranged closer to the second end of the longitudinal leg with respect to the axial direction and thus represents the axial winding upper end, the winding first end can also be regarded as the axial winding lower end. In the case of more than one winding being arranged at the longitudinal leg, the winding first end is the winding first end of the winding which is arranged closer to the first end of the longitudinal leg in the axial direction. In other words, the winding first end is the axial lower end of the axially lowermost winding arranged at the longitudinal leg. Here, the following definition applies as well: "lower" means closer to the first end of the longitudinal leg and "upper" means closer to the second end of the longitudinal leg.

[0033] It is advantageous for the first end portion of the shield to be arranged at the same height as the first end portion of the winding with respect to the axial direction, since the winding is primarily responsible for the stray field, since the magnetic field is generated there. The shield thus ensures an effective shielding of the magnetic field at the location where the magnetic field is generated and thus prevents the magnetic field from penetrating the stator housing.

[0034] It is of course also possible for the first end portion of the shield to be arranged below the first end portion of the winding in the axial direction. This can be advantageous, for example, for reasons of stability.

[0035] In another preferred embodiment, the first end portion of the shield is arranged above the first end portion of the winding with respect to the axial direction.

[0036] The stray field is particularly strong, especially in the upper region of the stator, i.e. in the region which is located more closely to the second end portion of the longitudinal leg in the axial direction. The reason for this is that the iron circuit is not closed there and thus the magnetically effective core of the rotor only conducts its own magnetic field, but not the magnetic field of the winding. On the other hand, in the lower region of the stator, i.e. in the region which is located more closely to the first end portion of the longitudinal leg in the axial direction, the magnetic field is well conducted by the back iron and there is significantly less stray field. It is therefore advantageous to arrange the shield in the upper region of the stator. A smaller extension of the shield in the axial direction also has the advantage that there is the possibility of building the stator more compactly, which means that less material is required, resulting in lower costs.

[0037] According to a preferred embodiment, the shield extends to a housing cover of the stator with respect to the axial direction, wherein the housing cover is arranged at the first end portion of the stator.

[0038] Here, different designs of the housing cover are possible and depending on its design, the shield can extend to the housing cover such that a contact between the two is possible. In the case of a housing cover made of plastic, the shield can be in contact with the housing cover since the plastic housing cover is not electrically conductive. In the case of a housing cover made of an electrically conductive material, there should be a distance between the shield and the housing cover, since otherwise the effect of reducing the eddy current losses can be reduced. It is also possible for the shield to have a thin region at its second end portion which extends over its entire extension in the circumferential direction and which is made of a non-conductive material. Such an insulating layer can also be achieved by coating the shield at the second end portion.

[0039] The maximum possible extension of the shield to the housing cover is advantageous, since, as already described, the majority of the stray field occurs at the axially upper end portion of the stator.

[0040] Furthermore, it is preferred for the shield to be made of a high permeability material, preferably of a high permeability material comprising iron and silicon.

[0041] In the framework of the present application, a high-permeability material is understood to be a material having a relative permeability μ > 40. Further properties of such materials are, inter alia, that they have a low electrical conductivity and a low hysteresis loss.

[0042] According to a preferred embodiment, the shield is designed as a coating, which is preferably applied to the radially inner positioned side of the stator housing. The coating has the advantage that it can be applied to an already existing stator housing by means of common coating methods known from the state of the art, such as PVD methods, thermal spraying. In doing so, the shield does not require additional material, such as an electrical metal sheet, and the shield can already be applied during the production of the stator housing, which saves additional work steps. Preferably, the coating comprises iron and / or plastic-bound metal particles. Preferably, the coating thickness is greater than 50 micrometers.

[0043] According to a preferred embodiment, the shield is designed as a metal sheet. Here, the metal sheet can comprise iron and / or silicon. There is also the possibility of using a μ-metal sheet and / or an electrical metal sheet, preferably a grain-oriented electrical metal sheet. It is possible that the metal sheet is bent into an annular shape and thus can be adapted to the outer shape of the coil core and the stator housing.

[0044] Furthermore, it is preferred that each coil core is made of an element in the form of a metal sheet, wherein the elements are stacked in the circumferential direction of the stator.

[0045] This means that several metal sheets in the form of coil cores are stacked in the circumferential direction insulated from one another. The metal sheet design of the coil cores prevents eddy currents of the magnetic field extending in the direction of the metal sheets, i.e. of the field following the longitudinal legs in the axial direction and the transverse legs in the radial direction. Here, too, an electrical metal sheet or a μ-metal sheet can be used as a preferred material.

[0046] According to a further preferred embodiment, two concentrated windings are arranged on each longitudinal leg, each of the two concentrated windings encircles the respective longitudinal leg, and the two concentrated windings are arranged adjacent to one another with respect to the axial direction.

[0047] According to a further preferred embodiment, the shield comprises at least two shield components, which are arranged adjacent to one another in the axial direction. This means that the at least two shield components can be stacked with respect to the axial direction. Here, it is possible that the individual shield components are made of different materials. It is also possible that the individual shield components are differently designed with respect to their shape.

[0048] Furthermore, it is preferred that the coil core has a rounding at the axial upper end, which reorients the coil core from the axial direction to the radial direction.

[0049] Furthermore, the application proposes an electromagnetic rotary drive which is designed as a temple motor, wherein the electromagnetic rotary drive comprises a magnetic levitation device according to the application and a rotor having a disc-shaped or ring-shaped magnetically effective core, wherein the rotor is insertable into a cup-shaped recess, and wherein the rotor is designed as a rotor of the electromagnetic rotary drive.

[0050] Such an electromagnetic rotary drive is also referred to as a bearingless motor. The term bearingless motor refers to an electromagnetic rotary drive in which the rotor is completely magnetically levitated relative to the stator, wherein no separate magnetic bearing is provided.

[0051] Further advantageous measures and embodiments of the application are apparent from the dependent claims. BRIEF DESCRIPTION OF DRAWINGS

[0052] In the following, the application will be explained in more detail with reference to embodiments and with reference to the drawings. In the drawings, the following is shown:

[0053] Figure 1 : perspective view of a first embodiment of a magnetic levitation device according to the application, wherein parts of the stator housing are removed,

[0054] Figure 2 : cross-sectional view of the first embodiment of a magnetic levitation device from Figure 1 : cross-sectional view of the first embodiment of a magnetic levitation device from

[0055] Figure 3 : cross-sectional view of a second embodiment of a magnetic levitation device according to the application,

[0056] Figure 4 : cross-sectional view of a third embodiment of a magnetic levitation device according to the application,

[0057] Figure 5 : cross-sectional view of a fourth embodiment of a magnetic levitation device according to the application,

[0058] Figure 6 : perspective view of a fifth embodiment of a magnetic levitation device according to the application, wherein parts of the stator housing are removed, and

[0059] Figure 7 : cross-sectional view of a sixth embodiment of a magnetic levitation device according to the application. DETAILED DESCRIPTION

[0060] Figure 1 A perspective view of a first embodiment of a magnetic levitation device according to the application is shown, which is designated in its entirety by the reference sign 1. The magnetic levitation device 1 is designed for contactless magnetic levitation of a rotor 3, which comprises a disc-shaped or ring-shaped magnetically effective core 31. The magnetic levitation device 1 is designed according to a temple construction and comprises a stator 2. The stator 2 comprises a stator housing 21, wherein, in the stator housing 21, a stator core 22 is arranged, which comprises a plurality of stator teeth 23, which are arranged in a stator slot 24. Figure 1In the representation, parts of the stator housing 21 are removed for a better overview, wherein a housing cover 212 is arranged at a first end of the stator 22, the housing cover 212 being connected to the stator housing 21 and being sealed such that no undesired substances can penetrate into the interior of the stator housing 21.

[0061] The stator housing 21 is usually made of metal, preferably of aluminum, the housing cover 212 in this case being made of plastic, preferably of polypropylene. The connection of the stator housing 21 and the housing cover 212 is preferably carried out by welding or gluing. However, it is also possible to make the stator housing 21 and the housing cover 212 of the same material. For example, it is also possible to use stainless steel as a material for the stator housing 21 and the housing cover 212.

[0062] In the housing cover 212, a cup-shaped recess 211 is provided into which the rotor 3 can be inserted. The rotor 3 is designed to rotate about a desired axis of rotation. This desired axis of rotation defines an axial direction A. Usually, a central axis of the stator 2 extending in the axial direction A coincides with the desired axis of rotation. The desired axis of rotation designates an axis about which the rotor 3 rotates in the operating state when the rotor 3 is in a centered and non-inclined position relative to the stator 2, as Figure 1 indicated in the representation.

[0063] The stator 2 has a plurality of coil cores 25, here six coil cores 25, each of which has a longitudinal leg 26 and a transverse leg 27. In the representation in Figure 1 , only three coil cores 25 are visible, the other three coil cores 25 being hidden in the representation by the stator housing 21. Each longitudinal leg 26 extends in the axial direction A from a first end 261 to a second end 262, wherein the transverse leg 27 is arranged at the second end 262, the transverse leg 27 extending in a radial direction R perpendicular to the axial direction A. A back iron 28 is arranged at the first end 261, the back iron 28 connecting the first ends 261 of all longitudinal legs 26.

[0064] The stator further has a cup-shaped recess 211 into which the rotor 3 can be inserted, wherein the cup-shaped recess 211 is arranged at an axially first end 22 of the stator 2. The transverse legs 27 are arranged around the cup-shaped recess 211.

[0065] At least one concentrated winding 61 is arranged at each longitudinal leg 26, the at least one concentrated winding 61 encircling the respective longitudinal leg 26. In the first embodiment, exactly one concentrated winding 61 is provided on each longitudinal leg 26. In other embodiments, more than one concentrated winding can also be arranged at the longitudinal leg 26. For example, there are embodiments in which Figure 4) : wherein exactly two concentrated windings 61a, 61b are provided on each of the longitudinal legs 26 in each case, each of the concentrated windings 61a, 61b encircling the respective longitudinal leg 26, wherein the two windings 61a, 61b arranged on the same longitudinal leg 26 are arranged adjacent to each other with respect to the axial direction A.

[0066] The concentrated windings 61 serve for generating an electromagnetic field with which the rotor 3 can be contactlessly magnetically levitated in the cup-shaped recess 211.

[0067] Furthermore, the stator 2 comprises a shield 4 which extends along the plurality of coil cores 25 in the circumferential direction. The shield 4 extends in the axial direction A from a shield first end 41 to a shield second end 42.

[0068] In this embodiment, the shield 4 is arranged radially outward around the coil cores 25 and extends over an angle of 280 degrees in the circumferential direction.

[0069] However, embodiments are possible in which the shield 4 extends over an angle of more than 360 degrees. Ideally, the shield 4 extends over an angle of at least 120 degrees, preferably at least 240 degrees.

[0070] If the shield 4 should extend over an angle of 360 degrees, this does not directly mean that it is closed in the circumferential direction. There can also be a distance between the first start 46 and the second start 47 of the shield 4. However, it is also possible that the first start 46 and the second start 47 are in contact or even overlap. In the latter case, an extension of the shield 4 over an angle of more than 360 degrees in the circumferential direction would be necessary. Embodiments are also possible in which notches are provided in the shield 4. For example, these notches can be provided for the feed-through of connectors, such as cables, through the shield 4.

[0071] For a better understanding, Figure 2 A cross-sectional view along the axial direction A of a first embodiment of a magnetic levitation device from Figure 1 is shown.

[0072] In this first embodiment, the shield 4 is designed in an annular manner, and the shield first end 41 is arranged lower, i.e. closer to the first end 261 of the longitudinal leg 26 than the winding first end 611 of the winding 61 in the axial direction A.

[0073] Here, the following definitions also apply: "lower" with respect to the axial direction A means closer to the first end 261 of the longitudinal leg 26, and "upper" with respect to the axial direction A means closer to the second end 262 of the longitudinal leg 26.

[0074] In the case where exactly one winding 61 is arranged at the longitudinal leg 26, the winding first end 611 means the end of the winding 61 which is positioned closer to the first end 261 of the longitudinal leg 26 in the axial direction A. If the winding second end 612 is arranged closer to the second end 262 of the longitudinal leg 26 with respect to the axial direction A and thus represents the axial winding upper end 612, the winding first end 611 can also be regarded as the axial winding lower end 611.

[0075] The shield first end 41 can also be arranged at the same height with respect to the axial direction A as the winding first end 611. Figure 3 This arrangement of the shield 4 can generally be sufficient, since the winding 61 is primarily responsible for the stray field, since the magnetic field is generated at the location of the winding. Thus, the shield 4 ensures an effective shielding of the magnetic field at this location of the generated magnetic field and thus prevents penetration into the stator housing 21. In the first embodiment, it can be advantageous for reasons of stability that the shield first end 41 is arranged below the winding first end 611.

[0076] However, embodiments are also possible in which the shield first end 41 is arranged above the winding first end 611 with respect to the axial direction A, here preferably between the winding first end 611 and the winding second end 612.

[0077] The stray field is particularly strong, especially in the upper region of the stator 2, i.e. in the region positioned closer to the second end 262 of the longitudinal leg 26 in the axial direction. The reason for this is that the iron circuit is not closed there and thus the magnetically effective core 31 of the rotor 3 only conducts its own magnetic field, but not the magnetic field of the winding 61. On the other hand, in the lower region of the stator 2, i.e. in the region positioned closer to the first end 261 of the longitudinal leg 26 in the axial direction, the magnetic field is well conducted by the back iron 28 and there is significantly less stray field. It is therefore advantageous to arrange the shield 4 at least in the upper region of the stator 2. A smaller extension of the shield 4 in the axial direction also has the advantage that there is the possibility of building the stator 2 more compactly, which means that less material is required, resulting in lower costs.

[0078] In this first embodiment, the shield 4 extends with respect to the axial direction A to the housing cover 212 of the stator 2, wherein the housing cover 212 is arranged at the first end 22 of the stator 2.

[0079] Here, the housing cover 212 is made of plastic, preferably of polypropylene, and the shield 4 is in contact with the housing cover 212, since the housing cover 212 made of plastic is not electrically conductive. In the case of a housing cover 212 made of an electrically conductive material, there must be a distance between the shield 4 and the housing cover 212, since otherwise the effect of reducing eddy current losses can be reduced. It is also possible that the shield 4 has a thin region at its shield second end portion 42 over its entire extension in the circumferential direction, which region extends in the axial direction A, and which region is made of a non-conductive material as an insulating layer. Such an insulating layer can also be achieved by coating the shield 4 at the shield second end portion 42. In this case, a contact between the shield 4 and the housing cover 212 is also possible if the shield 4 is made of an electrically conductive material.

[0080] A maximum possible extension of the shield 4 to the housing cover 212 is advantageous, since, as already described, most of the stray fields occur at the axially upper end portion 22 of the stator 2.

[0081] The shield 4 is preferably made of a high-permeability material. Here, it is preferred that this is a high-permeability material comprising iron and / or silicon. A high-permeability material is understood to be a material having a relative permeability μ > 40. Further properties of such a preferred material are, inter alia, that it has a low electrical conductivity and a low hysteresis loss.

[0082] Embodiments in which the shield 4 is designed as a metal sheet are also possible. The metal sheet can comprise iron and / or silicon. There is also the possibility of using a μ-metal sheet and / or an electrical metal sheet, preferably a grain-oriented electrical metal sheet, for the shield 4.

[0083] In the first embodiment, the coil core 25 is made of elements 253 in the form of metal sheets, wherein the elements 253 are stacked in the circumferential direction of the stator 2. The circumferential direction refers to a direction perpendicular to the radial direction R and perpendicular to the axial direction A. The elements 253 can be made of an electrical metal sheet, preferably a non-grain-oriented electrical metal sheet. The number of elements 253 in all embodiments and figures is to be understood as purely exemplary. The number can be greater or less than the number indicated.

[0084] In the first embodiment, the coil core 25 further has a rounding in each case at the axially upper end portion 252, which reorients the coil core 25 from the axial direction A to the radial direction R.

[0085] According to a particularly preferred embodiment, the stator 2 is designed such that, in addition to the contactless magnetic levitation of the rotor 3, the stator 2 can also exert a torque on the rotor 3 or on the magnetically effective core 31 of the rotor 3, which drives the rotor 3 to rotate about a desired axis of rotation. This means that, in this preferred embodiment, the rotor 3 can be driven by means of the stator 2 for rotation about the axial direction A.

[0086] In this embodiment, the concentrated winding 61 thus generates an electromagnetic rotating field with which the rotor 3 can both be contactlessly magnetically levitated relative to the stator 2 and contactlessly driven for rotation about the axial direction A.

[0087] It is understood that the number of six coil cores 25, although preferred, is to be understood merely as an example. Of course, embodiments are also possible in which the stator 2 has fewer than six, for example five or four or three, coil cores 25, or embodiments are also possible in which the stator 2 has more than six, for example seven or eight or nine, coil cores 25 or any larger number of coil cores 25.

[0088] The rotor 3 comprises a magnetically effective core 31 which is designed in an annular or disc-shaped manner. According to Figure 1 the representation in Fig. 1, the magnetically effective core 31 is designed as a ring and defines a magnetic center plane. Alternatively, the magnetically effective core 31 can also be designed as a disc. In general, in the case of a disc-shaped or annular magnetically effective core 31, the magnetic center plane is the geometric center plane of the magnetically effective core 31 of the rotor 3 which is perpendicular to the axial direction A. In the operating state, the magnetically effective core 31 is levitated in a radial plane which is perpendicular to the axial direction A.

[0089] The radial plane is indicated in Figure 1 by a line which is perpendicular to the radial direction R of the axial direction A. The radial plane is a plane which is perpendicular to the axial direction A and which contains the radial direction R. The radial plane is the plane in which the magnetically effective core 31 of the rotor 3 is actively magnetically levitated in the operating state. If the rotor 3 is not tilted and not deflected in the axial direction A, the magnetic center plane lies in the radial plane. The radial plane defines an x-y plane of a Cartesian coordinate system whose z-axis extends in the axial direction A.

[0090] The radial position of the magnetically effective core 31 or of the rotor 3 refers to the position of the rotor 3 in the radial plane.

[0091] Since this is sufficient for understanding the application, only the magnetically effective core 31 of the rotor 3 is represented in the drawings in Figure 1 and in Figure 2 It is understood that the rotor 3 can of course also comprise further components of the magnetically effective core 31, such as a sheath or an encapsulation, which is preferably made of plastic, or metal, or a metal alloy, or ceramic or a ceramic material. Furthermore, the rotor 3 can also comprise guide vanes for mixing, stirring or pumping a fluid or other components.

[0092] When the rotor 3 is inserted into the cup-shaped recess 211, 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 transverse legs 27 of the coil core 25 of the stator 2. Thus, the transverse legs 27 form a plurality of distinct stator poles, in this case six stator poles.

[0093] When the magnetically active core 31 of the rotor 3 is in its desired position during operation, the magnetically active core 31 is centered between the end faces 272 of the transverse legs 27. According to the representation, the concentrated windings 61 are arranged below the radial plane E and are aligned such that their coil axes extend in the axial direction A.

[0094] All first end portions 261 of the longitudinal legs 26, i.e. the lower end portions 261 according to the representation Figure 1 ) are connected to one another by the back iron 28. The back iron 28 is preferably designed in an annular fashion. Such an embodiment is possible, for example, see Figure 1 ), wherein the back iron 28 extends radially inwardly along all first end portions 261 of the longitudinal legs 26.

[0095] In order to generate the electromagnetic fields required for the magnetic levitation of the rotor 3 and optionally for the generation of a torque on the rotor 3, the longitudinal legs 26 of the coil core 25 carry windings designed as concentrated windings 61.

[0096] In the operating state, these concentrated windings 61 are utilized to generate those electromagnetic rotational fields with which a radially adjustable transverse force can be exerted on the rotor 3, with which the radial position of the rotor 3, i.e. its position in the radial plane perpendicular to the axial direction A, can be actively controlled or adjusted. Optionally, a torque is additionally realized on the rotor 3 with these electromagnetic rotational fields.

[0097] 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 generating a magnetic levitation force and optionally for generating a torque.

[0098] As already mentioned, in this embodiment the magnetically active core 31 is designed in an annular fashion. Furthermore, the magnetically active core 31 is designed in a permanent-magnetic fashion. For this purpose, the magnetically active core 31 can comprise at least one permanent magnet, but also several permanent magnets, or, as in the embodiment described here, completely consists of permanent-magnetic material, so that the magnetically active core 31 is a permanent magnet. For example, the magnetically active core 31 is magnetized in the radial direction.

[0099] Those ferromagnetic or ferrimagnetic materials which are magnetically hard, i.e. have a high coercive field strength, are typically referred to as permanent magnets. The coercive field strength is the magnetic field strength required to demagnetize the material. Within the framework of the present application, permanent magnets are understood to be components or materials which have a coercive field strength, more precisely a coercive field strength of the magnetic polarization, which totals more than 10'000 A / m.

[0100] Such embodiments are also possible in which the magnetically effective core 31 is designed in a permanent magnet-free manner, i.e. without permanent magnets. The rotor 3 is then designed as a reluctance rotor, for example. The magnetically effective core 31 of the rotor 3 is then made of a soft magnetic material, for example. Suitable soft magnetic materials for the magnetically effective core 31 are, for example, ferromagnetic or ferrimagnetic materials, i.e. in particular iron, nickel iron, cobalt iron, silicon iron, mu metal.

[0101] Furthermore, embodiments are possible in which the magnetically effective core 31 of the rotor 3 comprises both a ferromagnetic material and a permanent magnetic material. For example, permanent magnets can be placed or inserted into a ferromagnetic matrix. Such embodiments are advantageous, for example, if one wishes to reduce the costs of large rotors by saving permanent magnetic material.

[0102] Embodiments are also possible in which the rotor is designed according to the principle of a squirrel cage rotor.

[0103] The annular back iron 28 can be made of a soft magnetic material, since it serves as a flux conducting element which conducts the magnetic flux.

[0104] Suitable soft magnetic materials for the back iron 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, as a design of the stator 2, a design as a stator sheet stack is preferred, in which the back iron 28 is designed in sheet metal, i.e. it consists of several thin sheet metal elements which are stacked parallel to one another in the axial direction A. All elements are identically designed, i.e. in this case substantially annular, and also have the same thickness in each case. The back iron 28 itself is thus substantially designed in an annular manner and, in the assembled state, extends radially inwards along the first end portion 261 of the longitudinal leg 26.

[0105] Furthermore, it is possible that the back iron 28 consists 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, whereby eddy current losses can be minimized. Soft magnetic composite materials which consist of electrically insulated and compressed metal particles are thus also suitable for the stator 2. In particular, these soft magnetic composite materials, which are also designated as SMC (soft magnetic composite), can consist of iron powder particles which are coated with an electrically insulating layer. These SMCs are then formed into the desired shape by means of a powder metallurgical process.

[0106] Embodiments are also conceivable in which so-called tape-wound toroidal cores are used as back iron 28. This is a coiled strip made of an electrical sheet metal. Preferably, a grain-oriented electrical sheet metal is used here. At the state of the art, tape-wound toroidal cores are known primarily for use in transformers, transmitters, inductors, but not for use in bearing arrangements and in particular not for use in electromagnetic rotary drives.

[0107] During operation of the magnetic levitation device 1, the magnetically effective core 31 of the rotor 3 cooperates with the stator 2 in such a way that the rotor 3 can be magnetically levitated contactlessly with respect to the stator 2 and can preferably also be magnetically set into rotation contactlessly about the axial direction A. It is particularly advantageous in this case that the same windings 61 utilized for the magnetic levitation of the rotor 3 are also used for generating a torque on the rotor 3. Preferably, the three degrees of freedom of the rotor 3, i.e. its position in the radial plane and its rotation, can then be actively adjusted. With regard to its axial deflection from the radial plane in the axial direction A, the magnetically effective core 31 of the rotor 3 is passively magnetically stabilized by magnetic drag, i.e. it cannot be controlled. The magnetically effective core 31 of the rotor 3 is also passively magnetically stabilized with regard to its two remaining degrees of freedom, i.e. tilting with respect to the radial plane perpendicular to the desired axis of rotation. By the cooperation of the magnetically effective core 31 with the coil core 25, the rotor 3 is thus passively magnetically levitated or passively magnetically stabilized in the axial direction A and against tilting (three degrees of freedom in total) and actively magnetically levitated in the radial plane (two degrees of freedom).

[0108] As is generally the case, active magnetic levitation is also referred to in the framework of the present application as magnetic levitation which can be actively controlled or adjusted, for example by means of the electromagnetic field generated by the concentrated windings 61. Passive magnetic levitation or passive magnetic stabilization is magnetic levitation or magnetic stabilization which cannot be controlled or adjusted. Passive magnetic levitation or stabilization is based, for example, on magnetic drag, which brings the rotor 3 back again to its desired position when it is deflected therefrom, i.e. for example when the rotor 3 is displaced or deflected in the axial direction A or when the rotor 3 is tilted.

[0109] In the magnetic levitation device 1, in contrast to classic magnetic bearings, the magnetic levitation and optionally the generation of a torque acting on the rotor is realized by means of an electromagnetic rotary field. In order to combine the generation of the magnetic levitation force and the torque for rotating the rotor 3 about the axial direction A, it is possible, on the one hand, as shown in Figure 1 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 for rotating the rotor 3. For this purpose, for example, exactly two concentrated windings 61a, 61b are arranged in each case at each longitudinal leg 26 (see for example

[0110] 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 for rotating the rotor 3. For this purpose, for example, exactly two concentrated windings 61a, 61b are arranged in each case at each longitudinal leg 26 (see for example Figure 4) which are arranged next to each other with respect to the axial direction A. One of the two windings 61a, 61b belongs to a first winding system of the two winding systems and the other belongs to a second winding system of the two winding systems.

[0111] In the embodiment represented in Figure 1 , in which there is exactly one concentrated winding 61 at each coil core 25, the current values required for levitation and the current values required for generating a torque, which are determined in each case in the control unit, for example, are added or superimposed by calculation, for example by means of software. The resulting total current is then applied to the respective concentrated winding 61.

[0112] If the stator 2 of the magnetic levitation device 1 according to the application is designed for generating a torque, the magnetic levitation device 1 is suitable for an electromagnetic rotary drive which is designed as a temple motor. It is also possible that the magnetic levitation device 1 according to the application is suitable for other devices, such as a centrifugal pump, a mixing device for mixing flowable substances, for example a stirring device for mixing fluids in a tank, a fan, or also for a device for supporting and rotating a wafer, for example in semiconductor production.

[0113] Figure 3 A cross-sectional view of a second embodiment of the magnetic levitation device 1 according to the application is shown. The cross-section is performed along the axial direction A. In the following description of the second embodiment, only the differences to the first embodiment from Figure 1 are explained in more detail. The explanations of the first embodiment also apply in the same way or analogously to the second embodiment. Identical reference signs designate identical features or functionally equivalent features explained with reference to the first embodiment.

[0114] In the second embodiment, one difference is that the shield first end portion 41 is arranged at the same height as the winding first end portion 611 with respect to the axial direction A. The advantages thereof have already been explained.

[0115] Figure 4 A cross-sectional view of a third embodiment of the magnetic levitation device 1 according to the application is shown. The cross-section is performed along the axial direction A. In the following description of the third embodiment, only the differences to the preceding embodiments are explained in more detail. The explanations of the preceding embodiments also apply in the same way or analogously to the third embodiment. Identical reference signs designate identical features or functionally equivalent features explained with reference to the preceding embodiments.

[0116] In this embodiment, one difference is that the shield 4 is designed as a coating 43, which is preferably applied to the radially inner positioned side 213 of the stator housing 21. The coating 43 has the advantage that it can be applied to the already existing stator housing 21 by means of common coating methods known from the state of the art, such as PVD methods, thermal spraying. In doing so, the shield 4 does not require additional material, such as an electrical metal sheet, and the shield 4 can already be applied during the production of the stator housing 21, which saves additional work steps. Preferably, the coating 43 comprises iron and / or plastic-bound metal particles. Preferably, the coating thickness is greater than 50 micrometers.

[0117] The coating 43 can extend over the entire radially inner positioned side 213 of the stator housing 21 in the axial direction A or only over an extended portion of the radially inner positioned side 213 in the axial direction A. For example, it is possible to apply the coating 43 to the radially inner positioned side 213 of the stator housing 21 only in the region between the winding first end 611 and the winding second end 612. Preferably, the coating 43 extends over the entire circumference of the radially inner positioned side 213 of the stator housing 21.

[0118] Figure 5 A cross-sectional view of a fourth embodiment of a magnetic levitation device 1 according to the application is shown. In this case, the cross-section is performed in a radial plane. In the following description of the fourth embodiment, only the differences to the aforementioned embodiments are explained in more detail. The explanations of the aforementioned embodiments also apply in the same way or analogously to the fourth embodiment. Identical reference signs designate identical features or functionally equivalent features explained with reference to the aforementioned embodiments.

[0119] In this embodiment, one difference is that the shield 4 comprises two shield segments 45a, 45b, each of which extends in the circumferential direction from a segment first end 451a, 451b to a segment second end 452a, 452b. Here, the number of shield segments 45a, 45b is to be understood purely by way of example. The shield 4 comprises at least two shield segments 45a, 45b, but can also comprise more than two (for example three, four, five or even more) shield segments 45.

[0120] It is possible that the shield segments 45a, 45b are made of different materials.

[0121] In this embodiment, the shield segments 45a, 45b are arranged next to each other in the circumferential direction and have a distance to each other, i.e. in this embodiment the segment first end portions 451a, 451b and the segment second end portions 452a, 452b do not touch each other. However, it is also possible that all or only some of the segment end portions 451a, 451b, 452a, 452b touch each other or that the shield segments 45a, 45b overlap.

[0122] Embodiments are also possible in which the shield segments 45a, 45b are arranged next to each other in the axial direction A. Such embodiments are illustrated in Figure 6 .

[0123] Figure 6 A perspective view showing a fifth embodiment of the magnetic levitation device 1 according to the application is shown, in which parts of the stator housing 21 are removed. In the following description of the fifth embodiment, only the differences to the previous embodiments are explained in more detail. The explanations of the previous embodiments also apply in the same way or analogously to the fifth embodiment. Identical reference signs designate identical features or functionally equivalent features explained with reference to the previous embodiments.

[0124] One difference to the previous embodiments is that in this embodiment the shield 4 comprises several, here three, shield segments 45a, 45b, 45c which are arranged next to each other with respect to the axial direction A. The number of shield segments 45a, 45b, 45c is to be understood as purely exemplary. In this embodiment, the extension of the individual shield segments 45a, 45b, 45c is different compared to each other. In other words, the width of the individual shield segments 45a, 45b, 45c in the axial direction A is different. However, embodiments are also possible in which the shield segments 45a, 45b, 45c have the same width in the axial direction A. In this embodiment, the three shield segments 45a, 45b, 45c all have the same shape. However, it is also possible that in other embodiments the individual shield segments 45a, 45b, 45c are designed differently with respect to their shape. Here, it should be noted that the shield segments 45a, 45b, 45c are designed such that they can be arranged next to each other with the corresponding respective axial segment first end portions 41a, 41b, 41c and the corresponding respective axial segment second end portions 42a, 42b, 42c.

[0125] A second difference is that the coil core 25 does not have a rounding at the axial upper end 252. A further difference is that here exactly two concentrated windings 61a, 61b are provided on each longitudinal leg 26, each of the two concentrated windings 61a, 61b encircles the respective longitudinal leg 26 and the two concentrated windings 61a, 61b are arranged next to each other with respect to the axial direction A. In the case of more than one winding 61a, 61b arranged at the respective longitudinal leg 26, the winding first end 611 is the winding first end 611 of this winding 61a which is arranged closer to the first end 261 of the longitudinal leg 26 in the axial direction A. In other words, the winding first end 611 is the axial lower end of the axially lowermost winding 61a arranged at the longitudinal leg 26. Here, the following definitions also apply: "lower" means closer to the first end 261 of the longitudinal leg 26 and "upper" means closer to the second end 262 of the longitudinal leg 26.

[0126] Figure 7 A cross-sectional view of a sixth embodiment of a magnetic levitation device 1 according to the application is shown. In this case, the cross-section is performed in a radial plane. In the following description of the sixth embodiment, only the differences to the previously described embodiments are explained in more detail. The explanations of the previously described embodiments also apply in the same way or analogously to the sixth embodiment. Identical reference signs designate identical features or functionally equivalent features explained with reference to the previously described embodiments.

[0127] Here, one difference is that the shield is designed as a strip 44, wherein the strip 44 forms several strip windings 441 which lie against each other with respect to the radial direction R. It is particularly preferred that the several strip windings 441 are insulated from each other.

[0128] Here, the strip 44 can be made of an electrical metal sheet, preferably of a grain-oriented electrical metal sheet. According to the general definition, an electrical metal sheet is understood to be a soft-magnetic material for magnetic cores. There is also the possibility of using μ-metal for the strip 44.

[0129] Here, the advantage is that such a strip 44 is frequently used in technology and is therefore cost-effective. It is also advantageous that the strip 44 can be produced relatively easily and it is possible to insulate the strip windings 441 from each other directly during production.

[0130] It goes without saying that all embodiments shown in the description of the figures with their respective features can be combined with each other in any way.

[0131] Furthermore, it is possible that all shown embodiments can be designed with a coil core 25 which is 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 outer shape of the coil core 25.

[0132] In this process, the coil core 25 is divided into an axially lower section and an axially upper section, wherein the lower section and the upper section are arranged adjacent to each other with respect to the axial direction A. The transverse leg 27 is arranged at the axially upper section. For each coil core 25, the end face 272 of the transverse leg 27 has a first distance in the radial direction to the axially lower section of the associated longitudinal leg 26 and a second distance in the radial direction to the axially upper section, wherein the second distance is larger than the first distance. This means that each longitudinal leg 26 is designed such that the axially upper section is displaced outward in the radial direction with respect to the axially lower section, such that the space available between the end faces 272 for the rotor 3 is increased without the risk of a direct transfer of the magnetic flux between the longitudinal leg 26 and the magnetically effective core 31 of the rotor 3. Due to the fact that the axially upper section is offset radially outward with respect to the radial direction and with respect to the axially lower section, the distance between the longitudinal leg 26 and the end face 272, i.e. the second distance, increases in the region of the axially upper section. In doing so, the distance between the magnetically effective core 31 of the rotor and the longitudinal leg 26, in particular in the region of the axially upper section, also increases.

[0133] Such coil cores 25 just described are designed similar to those coil cores illustrated in Fig. 1 of European patent application EP 4084304 A1. Figure 3 Fig. 2 of European patent application EP 4084304 A1.

Claims

1. Magnetic suspension device for contactless magnetic suspension of a rotor (3) comprising a disc-shaped or ring-shaped magnetically active core (31), wherein The magnetic levitation device has a stator (2) with a stator housing (21), which comprises a plurality of coil cores (25), each of which comprises a longitudinal leg (26) extending in an axial direction (A) from a first end (261) to a second end (262) and a transverse leg (27) arranged at the second end (262) of the longitudinal leg and extending in a radial direction (R) perpendicular to the axial direction (A), wherein a back iron (28) is arranged at the first end (261), which connects the first ends (261) of all longitudinal legs (26), wherein at least one concentrated winding (61; 61a, 61b) is provided on each longitudinal leg (26) around the respective longitudinal leg (26), wherein the stator (2) further has a cup-shaped recess (211) into which the rotor (3) can be inserted, wherein the cup-shaped recess (211) is arranged at an axial end of the stator (2) and wherein the transverse leg (27) is arranged around the cup-shaped recess (211), characterized in that the stator (2) comprises a shield (4) which extends in a circumferential direction along the plurality of coil cores (25) and wherein the shield (4) extends in the axial direction (A) from a shield first end (41) to a shield second end (42).

2. The magnetic levitation device of claim 1, wherein, The shield (4) is arranged radially outward around the coil cores (25) and extends over an angle of at least 120 degrees, preferably at least 240 degrees, in the circumferential direction.

3. The magnetic levitation device of any of the preceding claims, wherein, The shield (4) is designed in an annular manner.

4. The magnetic levitation device according to any one of the preceding claims, wherein, The shield (4) comprises at least two shield segments (45a, 45b), each of which extends in the circumferential direction from a segment first end (451a, 451b) to a segment second end (452a, 452b).

5. The magnetic levitation device of claim 4, wherein, The shield segments (45a, 45b) are arranged next to each other in the circumferential direction.

6. The magnetic levitation device of any one of claims 1 to 3, wherein, The shield (4) is designed as a strip (44), wherein the strip (44) forms several strip windings (441) lying against each other with respect to the radial direction (R).

7. The magnetic levitation device of any of the preceding claims, wherein, The shield first end (41) is arranged at the same height with respect to the axial direction (A) as a winding first end (611).

8. The magnetic levitation device of any one of claims 1 to 5, wherein, The shield first end (41) is arranged above the winding first end (611) with respect to the axial direction (A).

9. The magnetic levitation device of any of the preceding claims, wherein, The shield (4) extends with respect to the axial direction to a housing cover (212) of the stator (2), wherein the housing cover (212) is arranged at a first end (22) of the stator (2).

10. The magnetic levitation device of any of the preceding claims, wherein, The shield (4) is made of a high-permeability material, preferably a high-permeability material comprising iron and silicon.

11. The magnetic levitation device of any one of claims 1 to 3, 6 to 9, wherein, The shield (4) is designed as a coating (43), which is preferably applied to a radially inner positioned side (213) of the stator housing (21).

12. The magnetic levitation device of any one of claims 1 to 9, wherein, The shield (4) is designed as a metal sheet.

13. The magnetic levitation device of any of the preceding claims, wherein, Two concentrated windings (61a, 61b) are arranged on each longitudinal leg (26), each of the two concentrated windings encircles the respective longitudinal leg (26) and the two concentrated windings are arranged adjacent to each other with respect to the axial direction (A).

14. The magnetic levitation device of any of the preceding claims, wherein, The stator (2) is designed to generate a torque with which the rotor (3) can be driven magnetically contactlessly for rotation about the axial direction (A).

15. Electromagnetic rotary drive, designed as a temple-like motor, characterized in that The electromagnetic rotary drive comprises a magnetic levitation device (1) according to claim 14 and a rotor (3) having a disc-shaped or ring-shaped magnetically effective core (31), wherein the rotor (3) is insertable into the cup-shaped recess (211) and wherein the rotor (3) is designed as the rotor (3) of the electromagnetic rotary drive.

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