Magnetic suspension device and centrifugal pump

Abstract

The invention relates to a magnetic levitation device for contactless magnetic levitation of a rotor comprising a disc-shaped or annular magnetic effective core. A magnetic levitation device has a stator including a plurality of coil cores, each coil core including 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. At least one concentrated winding is provided at each longitudinal leg, the winding surrounding the respective longitudinal leg. The stator also has a cup-shaped recess into which the rotor is insertable. The cup-shaped recess is arranged at an axial end of the stator. The transverse legs are arranged around the cup-shaped recess. A first holding device and a second holding device that can be connected to each other are provided. The first holding device comprises a base plate on which a plurality of holding elements are provided, each holding element extending in an axial direction and receiving exactly one of the longitudinal legs. The second retaining device receives the lateral leg.

Description

Technical Field

[0001] The invention relates to a magnetic levitation device according to the preamble of the independent patent claim and to a centrifugal pump having such a magnetic levitation device. Background Art

[0002] Magnetic bearing devices for contactless magnetic support of the rotor have the following advantages: They do not require mechanical bearings for the rotor. The rotor is supported or stabilized by means of the magnetic forces generated by the stator of the magnetic bearing device. Due to the absence of mechanical bearings, such magnetic bearing devices are particularly suitable for use in pumping, mixing or stirring devices for conveying very sensitive substances, such as blood pumps, or for very high demands on purity, such as in the pharmaceutical industry or biotechnology, or for conveying abrasive or aggressive substances that can very quickly destroy mechanical bearings, such as pumps or mixers for slurries, sulfuric acid, phosphoric acid or other chemicals in the semiconductor industry.

[0003] An advantageous design of a magnetic bearing device known per se is that in the form of a temple, to which the present invention also relates.

[0004] The characteristic feature of the temple construction is that the stator of the magnetic bearing device has a plurality of coil cores, each of the coil cores comprising a longitudinal leg extending from a first end in an axial direction to a second end. Here, the axial direction 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 of rotation about which the rotor rotates in an operating state when the rotor is in a centered and non-tilted position relative to the stator. In addition to the longitudinal legs, each coil core 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 toward the inside, wherein the radial direction is perpendicular to the axial direction. Therefore, the transverse leg extends substantially at right angles to the longitudinal leg. The coil cores each have an L-shape, wherein the transverse leg forms the short leg of the L. The rotor to be supported is then arranged between the transverse legs.

[0005] The multiple longitudinal legs extending in the axial direction and reminiscent of temple columns give the construction its name.

[0006] 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 ends of the longitudinal legs are usually connected in the circumferential direction via a back iron, which serves to conduct the magnetic flux. The rotor to be supported comprises a magnetically active core, for example a permanent magnetic disk or a permanent magnetic ring, which is arranged between the radially inner ends of the transverse legs and rotates about the axial direction in the operating state, wherein the rotor is magnetically supported relative to the stator without contact.

[0007] For such magnetic bearing arrangements, the magnetically active core of the rotor does not necessarily have to be designed in a permanent-magnetic manner. Such designs are also known in which the magnetically active core of the rotor is designed in a non-permanent-magnetic manner, i.e. without permanent magnets. The magnetically active core of the rotor is then, 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.

[0008] Furthermore, designs are possible in which the magnetically active core of the rotor comprises both ferromagnetic material and permanent magnet material. For example, permanent magnets may be placed or inserted into a ferromagnetic matrix. Such designs are advantageous, for example, if one wishes to reduce the cost of a large rotor by saving permanent magnet material.

[0009] The longitudinal legs carry windings for generating the electromagnetic rotating fields required 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 construction that the coil axis of the concentrated windings extends in the axial direction and that the concentrated windings are not arranged in a radial plane, in which the rotor or the magnetically active core of the rotor is supported in the operating state.

[0010] A design is possible in which exactly one concentrated winding is arranged on each longitudinal leg. In other designs, several (e.g. exactly two) concentrated windings are provided on each longitudinal leg. A design is also possible in which the winding is arranged to be wound around two longitudinal legs adjacent in the circumferential direction, so that both of the two adjacent longitudinal legs are located inside the concentrated winding.

[0011] In the case of known magnetic bearing arrangements in temple construction, assembly of the magnetic bearing arrangement is usually associated with relatively great effort, since the individual components of the stator have to be positioned relative to one another with high precision before they are fixed, for example by means of a casting compound which completely fills the stator housing. Summary of the invention

[0012] Starting from the prior art, the object of the present invention is therefore to provide a magnetic levitation device for contactless magnetic levitation of a rotor with an annular or disk-shaped magnetically active core, which allows a particularly simple assembly of the stator of the magnetic levitation device. In addition, the object of the present invention is to provide a centrifugal pump with such a magnetic levitation device.

[0013] The subject matter of the invention which meets this object is characterized by the features of the independent patent claims.

[0014] According to the invention, a magnetic levitation device for contactless magnetic levitation of a rotor is thus proposed, the rotor comprising a disk-shaped or annular magnetically active core, wherein the magnetic levitation device has a stator, the stator comprising a plurality of coil cores, each of the coil cores comprising a longitudinal leg extending from a first end in an axial direction 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 at least one concentrated winding is provided at each longitudinal leg, the winding surrounding the respective longitudinal leg, wherein the stator further comprises 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 leg is arranged around the cup-shaped recess. A first holding device and a second holding device are provided, the first holding device and the second holding device being connectable to each other, wherein the first holding device comprises a base plate, a plurality of holding elements are provided on the base plate, each of the holding elements extending in the axial direction, and each of the holding elements is designed to receive exactly one of the longitudinal legs, and wherein the second holding device is designed to receive the transverse leg.

[0015] Due to the two holding devices, it is possible to assemble the stator of the magnetic levitation device in a particularly easy manner. The longitudinal legs of the coil core are pushed into the holding elements of the first holding device. Subsequently, the windings can be arranged on the coil core so that they surround the longitudinal legs. The second holding element is then placed on the transverse legs of the coil core and connected to the first holding element, for example by means of screws. The stator housing can then be filled with a hot potting compound and the coil core with the windings is arranged in the stator housing. Here, the two mutually connected holding elements ensure that the individual components of the stator are in the correct position relative to each other.

[0016] According to a preferred embodiment, the stator has a receiving pot which forms an axial end of the stator, wherein the receiving pot has a cup-shaped recess into which the rotor can be inserted. In this preferred embodiment, a separate receiving pot with a cup-shaped recess is therefore provided.

[0017] In an alternative embodiment, the cup-shaped recess is not realized by a separate component, but is formed, for example, when the stator housing is filled with a hot potting compound. For this purpose, for example, a cylinder, for example a plastic cylinder, is inserted into the stator or the stator housing as a negative mold during the filling of the stator housing and is placed so that it occupies the position in which the cup-shaped recess is to be formed later. The potting compound then flows partially around the cylinder. After the potting compound has hardened, the cylinder is removed, whereby the cup-shaped recess is formed in the stator. In this embodiment, the cup-shaped recess is therefore formed by the potting compound.

[0018] Preferably, an annular back iron is arranged for conducting magnetic flux, the back iron connecting the first ends of all longitudinal legs, wherein the bottom plate of the first holding device is designed to receive the back iron. Thus, the back iron is arranged in the correct position relative to the coil core.

[0019] According to a preferred embodiment, the back-iron is arranged radially inwardly at the first end of the longitudinal leg.

[0020] For detecting the position of the rotor to be suspended, it is advantageous if a circuit board with electronic components is arranged between the winding and the transverse leg relative to the axial direction, wherein the second holding device is designed to receive the circuit board. The electronic components include, for example, Hall sensors or eddy current sensors, with which the position of the rotor can be detected in the operating state. Due to the fact that the second holding device is designed to receive the circuit board, it is very easy to correctly position the circuit board.

[0021] Preferably, the circuit board is designed in an annular manner and is arranged so that the electronic components are arranged around the cup-shaped recess of the receiving pot. In this way, the position of the rotor in the cup-shaped recess can be determined particularly well and reliably.

[0022] Particularly for structural reasons, it is preferred that the receiving pot surrounds the second holding device radially outwardly. In this case, the axial end region of the second holding device is arranged inside the receiving pot and is completely surrounded by it when viewed in the circumferential direction.

[0023] For the first retaining device, it is preferred that each retaining element of the first retaining device is arranged in each case between one of the longitudinal legs and the winding arranged on this longitudinal leg with respect to the radial direction and extends with respect to the axial direction at least to the ends of all windings arranged on the respective longitudinal leg. Regardless of whether one winding or a plurality of windings are arranged on the respective longitudinal leg, the retaining element extends in the axial direction at least as far as the windings extend with their ends facing the transverse leg.

[0024] According to a preferred embodiment, each retaining element comprises a plurality of rods with free spaces located between them, wherein each rod extends in an axial direction.

[0025] Preferably, the rods of the holding elements are arranged and designed such that they exert a spring force on the longitudinal legs received by the respective holding element. In this way, the coil core can be positioned particularly precisely.

[0026] For example, each longitudinal leg has a rectangular cross section perpendicular to the axial direction, wherein exactly one of the rods is arranged at each corner of the longitudinal leg. Here, the rods preferably each have an angled profile so that each rod surrounds a corner of the longitudinal leg in each case.

[0027] Preferably, the first holding device or the second holding device is made of plastic. Particularly preferably, the first holding device and the second holding device are each made of plastic. For example, the first holding device and the second holding device are each designed as an injection molded part manufactured by means of an injection molding process.

[0028] Furthermore, it is preferred that the holding tank is made of plastic. The holding tank can also be designed as an injection-molded part.

[0029] Preferably, the control unit is provided for controlling the winding and for supplying the winding with electrical energy for generating the electromagnetic rotating field.

[0030] According to a particularly preferred embodiment, the stator of the magnetic levitation device is designed to generate a torque with which the rotor can be driven magnetically without contact for rotation about an axial direction.

[0031] Furthermore, the invention proposes a centrifugal pump for conveying fluids, which comprises the magnetic levitation device according to the invention and a rotor with a magnetically active core, wherein the rotor can be inserted into a cup-shaped recess of a receiving tank and wherein the rotor is designed as a rotor of a centrifugal pump.

[0032] Further advantageous measures and embodiments of the invention are apparent from the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the following, the present invention will be explained in more detail with reference to an embodiment and with reference to the drawings. In the drawings:

[0034] Figure 1 : A schematic cross-sectional view of an embodiment of a magnetic levitation device according to the present invention,

[0035] Figure 2 : A perspective view of the stator of this embodiment viewed from the direction of the containing tank,

[0036] Figure 3 : A perspective view of the stator of this embodiment viewed from the bottom plate direction of the first holding device,

[0037] Figure 4 : Perspective exploded view of the stator,

[0038] Figure 5 : Perspective view of the coil core,

[0039] Figure 6 :like Figure 5 , but for a variation of the coil core,

[0040] Figure 7 : Perspective view of the back iron,

[0041] Figure 8 : A perspective view of the second holding device,

[0042] Fig. 9 : A perspective view of an embodiment of a circuit board with electronic components,

[0043] Fig.10: Top view from the direction of the first end of the coil core onto the second holding device with the circuit board,

[0044] Fig.11 : A perspective view of a first holding device,

[0045] Fig.12 : A perspective view of a first holding device with a concentrated winding on the holding element,

[0046] Fig.13 : A perspective view of the stator holding tank,

[0047] Fig.14 : From Fig.13 A cross-sectional view of the holding tank, and

[0048] Fig.15 : A schematic cross-sectional view of an embodiment of a centrifugal pump according to the present invention, showing a cross section along the axial direction. DETAILED DESCRIPTION

[0049] Figure 1 A schematic cross-sectional view of an embodiment of a magnetic levitation device according to the invention is shown, which is designated in its entirety by the reference symbol 1. The magnetic levitation device 1 is designed for contactless magnetic levitation of a rotor 3, which comprises a disk-shaped or annular magnetically active core 31. The magnetic levitation device 1 is designed according to a temple construction and comprises a stator 2 having a plurality of coil cores 25 - here six coil cores 25 - each of which comprises a longitudinal leg 26 extending from a first end 261 in an axial direction A to a second end 262, and a transverse leg 27 arranged perpendicularly to the longitudinal leg 26, which extends in a radial direction perpendicular to the axial direction A. Each transverse leg 27 is delimited with respect to the radial direction by an end face 271, which forms a pole of the associated coil core 25.

[0050] The stator 2 includes a stator housing 20 in which a coil core 25 is arranged. For a better understanding, Figures 2 to 4 A more detailed illustration of the stator 2 of an embodiment of the magnetic levitation device 1 is shown. Figure 2 and Figure 3 Two perspective views of the stator 2 are shown, wherein the stator housing 20 is not represented. Figure 2 and Figure 3 The viewing directions in the reference Figure 1 In the diagram, people Figure 2 The stator 2 is viewed from above and Figure 3 The stator 2 is viewed obliquely from below. Figure 4 Still showing a perspective exploded view of the stator 2. The stator housing 20 is also not shown. Figure 4 Presented in.

[0051] The stator housing 20 is preferably made of a metal material, such as aluminum or stainless steel. For better chemical resistance, the stator housing 20 may be provided with a coating, preferably a plastic coating made of a highly chemically resistant plastic. Examples of such plastics are PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy polymer), ECTFE (ethylene chlorotrifluoroethylene), ETFE (ethylene tetrafluoroethylene), epoxy resin (polyepoxy resin), PPA (polyphthalamide), PE (polyethylene).

[0052] The stator 2 further comprises a receiving pot 21 having a cup-shaped recess 211 into which the rotor 3 to be suspended can be inserted (see Figure 1 ). The accommodating tank 21 forms one of the two axial ends of the stator 2. Figure 1 , which is the upper axial end of the stator 2.

[0053] The transverse leg 27 of the coil core 25 is arranged in the receiving pot 21 such that an end face 271 of the transverse leg 27 is arranged around the cup-shaped recess 211 .

[0054] The containment pot 21 is firmly connected to the stator housing 20, for example by means of a form-locking connection (not presented) or by means of an elastic seal (not presented). Preferably, the containment pot 21 is connected to the stator housing 20 in an airtight manner, so that the stator housing 20 and the containment pot 21 together form an airtight housing in which the other components of the stator 2 are encapsulated in an airtight manner. The stator housing 20 is preferably filled with a thermally conductive potting material, such as epoxy resin or polyurethane, so that the components arranged inside the stator housing 20 are surrounded by the potting material. In this way, the overall thermal resistance is reduced and vibrations are also attenuated.

[0055] The coil cores 25 of the stator 2 are arranged equidistantly on a circular line, so that when the rotor 3 is inserted into the cup-shaped recess 211, the end surface 271 surrounds the magnetically active core 31 of the rotor 3. Exactly two concentrated windings 61a, 61b are provided on each longitudinal leg 26 in each case, each of these concentrated windings 61a, 61b surrounding 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. In other embodiments, exactly one concentrated winding 61 is arranged at each longitudinal leg 26 (see, for example, Fig.12 ), these concentrated windings 61 surround the corresponding longitudinal legs 26.

[0056] The concentrated windings 61 a , 61 b ​​are used to generate an electromagnetic field, with which the rotor 3 can be magnetically suspended in the cup-shaped recess 211 of the accommodating pot 21 without contact.

[0057] Furthermore, the control unit 40 is provided for controlling the windings 61a, 61b and supplying the windings 61a, 61b with electrical energy. The control unit 40 comprises in particular power electronics, such as inverters or rectifiers, for feeding the required current into the windings 61a, 61b. The control unit 40 is only Figure 1 Particularly preferably, the control unit 40 is also arranged inside the stator housing 20, for example according to the diagram ( Figure 1 ) is arranged below the first end 261 of the longitudinal leg 26 of the coil core 25. The control unit 40 is preferably also potted or coupled to the stator housing 20 and the back iron 22 of the stator 2 and / or the coil core 25 using a heat potting compound.

[0058] Using exemplary features, Figure 1 4 . Some components of the control unit 40 are presented in FIG. 4 . For example, the control unit 40 comprises a first electronic device board 41 on which electronic components 42 are arranged, for example power electronic devices for controlling the windings 61a, 61b. In addition, the control unit 40 optionally has a second electronic device board 43, which has electronic components 42. For example, the second electronic device board 43 can contain evaluation electronics for evaluating signals from sensors (for example flow sensors), and / or can be used as a communication interface. The electronic device boards 41, 43 can be connected to each other via a connector 44. To name just a few examples, the connector 44 can be designed as a plug-in connector or as a flat ribbon cable or a male pin or a flexible printed board. In addition, a connecting cable 45 is provided, which is connected to the first electronic device board 41 via a cable connector 46 or a plug. The connecting cable 45 is led out of the stator housing 20 and is used, for example, to supply power to the magnetic levitation device 1. The connecting cable 45 is led out of the stator housing 20 by means of a cable bushing 47 of sealed design. Preferably, the cable bushing is designed in a gas-tight sealing manner.

[0059] The first electronics board 41 is connected to the windings 61a, 61b via connection lines 48, for example cables, in order to control them and supply them with energy. Only a few of the connection lines are presented with exemplary features.

[0060] Located in the interior space surrounded by the longitudinal legs 26 Figure 1 The space indicated by the reference symbol 49 in the figure can be used for further electronic components, electronic device boards or plugs or connectors. For reasons of better overview, these are not shown in the figure. Figure 1 Presented in.

[0061] According to a particularly preferred embodiment, the stator 2 is designed such that, in addition to the contactless magnetic suspension of the rotor 3, it can also exert a torque on the rotor 3 or the magnetically active core 31 of the rotor 3, which drives the rotor 3 in rotation about the desired axis of rotation. Figure 1, the desired rotation axis specifies the axis about which the rotor 3 rotates in an operating state when the rotor 3 is in a centered and non-tilted position relative to the stator 2. The desired rotation axis extends in the axial direction A, i.e., in the preferred embodiment, the rotor arranged in the receiving pot 21 of the stator 2 can be driven for rotation around the axial direction A. Typically, the desired rotation axis coincides with the center axis of the stator 2, which extends in the axial direction A.

[0062] In this exemplary embodiment, the concentrated windings 61 a , 61 b ​​therefore generate an electromagnetic rotating field with which the rotor 3 can be both magnetically suspended relative to the stator 2 without contact and also driven for rotation about the axial direction A without contact.

[0063] It is to be understood that the number of six coil cores 25 is understood only as an example. Of course, such embodiments in which the stator 2 has less than six (e.g., five or four or three) coil cores 25 or such embodiments in which the stator 2 has more than six (e.g., seven or eight or nine) coil cores 25 or any greater number of coil cores 25 are also possible.

[0064] The rotor 3 comprises a magnetically active core 31 which is designed in an annular or disk-shaped manner. Figure 1 As shown in the figure, 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 disk. Generally, in the case of a disk-shaped or ring-shaped 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 suspended in a radial plane E perpendicular to the axial direction A. The radial plane is Figure 1 In the diagram, the radial plane E is indicated by a line E which is perpendicular to the axial direction A. Therefore, the radial plane E is a plane which is perpendicular to the axial direction A and contains the line E.

[0065] The radial plane E is the plane in which the magnetically active core 31 of the rotor 3 is actively magnetically suspended between the end faces 271 of the stator 2 in the operating state. If the rotor 3 is not tilted and is not deflected in the axial direction A, the magnetic center plane is located in the radial plane E. The radial plane E defines the xy plane of a Cartesian coordinate system whose z-axis extends in the axial direction A.

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

[0067] As is sufficient for understanding the present invention, Figure 1Only the magnetically active core 31 of the rotor 3 is presented in the figure. It is to be understood that the rotor 3 can of course also comprise further components, such as a jacket or an encapsulation, which is preferably made of plastic, metal or a metal alloy or ceramic or a ceramic material. In addition, the rotor 3 can also comprise blades for mixing, stirring or pumping the fluid (see for example Fig.15 ) or other components.

[0068] When the rotor 3 is inserted into the cup-shaped recess 211 of the receiving pot 21, the rotor 3 and in particular the magnetically active core 31 of the rotor 3 are surrounded by the radially outwardly arranged end faces 271 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. The transverse legs 27 are arranged at the upper ends of the longitudinal legs 26 and in the radial plane E. Each transverse leg 27 extends in the radial direction toward the rotor 3.

[0069] 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 271 of the transverse legs 27, so that the transverse legs 27 arranged in the radial plane E are also located in the magnetic center plane. According to this illustration, the concentrated windings 61a, 61b are arranged below the radial plane E and are aligned so that their coil axes extend in the axial direction A.

[0070] All first ends 261 of the longitudinal legs 26 (i.e., according to the diagram ( Figure 1 ) are connected to each other through the back iron 22. Preferably, the back iron 22 is designed in a ring-shaped manner. Such embodiments are possible (see, for example, Figure 1 ), wherein the back iron 22 extends radially inward along all first ends 261 of the longitudinal legs 26.

[0071] In order to generate the electromagnetic rotating fields required for magnetically levitating the rotor 3 and optionally generating a torque on the rotor 3 , the longitudinal legs 26 of the coil core 25 carry windings designed as concentrated windings 61 a, 61 b, wherein in the embodiment described here exactly two concentrated windings 61 a, 61 b ​​are arranged in each case around each longitudinal leg 26 , which are adjacent with respect to the axial direction A. In the operating state, electromagnetic rotating fields are generated with these concentrated windings 61 a, 61 b, with which any adjustable transverse forces in the radial direction can be exerted on the rotor 3 , so that the radial position of the rotor 3 , i.e. its position in a radial plane E perpendicular to the axial direction A, can be actively controlled or adjusted. Optionally, these electromagnetic rotating fields can additionally generate a torque on the rotor 3 .

[0072] The “magnetically active core 31 ” of the rotor 3 refers to the area of ​​the rotor 3 that magnetically interacts with the stator 2 to generate a magnetic levitation force and optionally a torque.

[0073] As already mentioned, in this embodiment, the magnetically active core 31 is designed in an annular manner. Furthermore, the magnetically active core 31 is designed in a permanent magnetic manner. For this purpose, the magnetically active core 31 may include at least one permanent magnet, but may also include several permanent magnets, or—as in the embodiment described here—completely consist 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.

[0074] Those ferromagnetic or ferrimagnetic materials that are hard magnetic (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 a material. Within the framework of this application, a permanent magnet is understood to be a component or material having a coercive field strength, more precisely a magnetic polarization coercive field strength, of greater than 10'000 A / m.

[0075] Such an embodiment is also possible in which the magnetically active core 31 is designed without permanent magnets, 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.

[0076] Furthermore, embodiments are possible in which the magnetically active core 31 of the rotor 3 comprises both ferromagnetic material and permanent magnetic material. For example, permanent magnets may be placed or inserted into a ferromagnetic matrix. Such embodiments are advantageous, for example, if one wishes to reduce the cost of a large rotor by saving permanent magnetic material.

[0077] Embodiments are also possible in which the rotor is designed according to the principle of a cage rotor.

[0078] Both the annular back iron 22 and the coil core 25 of the stator 2 are each made of a soft magnetic material because they serve as magnetic flux conducting elements to conduct magnetic flux.

[0079] Suitable soft magnetic materials for the coil core 25 and the back iron 22 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 design as a stack of stator sheets is preferred for the stator 2, wherein the coil core 25 and the back iron 22 are designed as metal sheets, i.e. they consist of several stacked thin metal sheet elements.

[0080] In addition, it is possible that the coil core 25 and the back iron 22 can be composed of particles of the above-mentioned materials that are pressed and then sintered. The metal particles are preferably embedded in a plastic matrix so that they are at least partially insulated from each other, thereby minimizing eddy current losses. Therefore, soft magnetic composites composed of electrically insulating and compressed metal particles are also suitable for use in stators. In particular, these soft magnetic composites, which are also designated as SMC (soft magnetic composites), can be composed of iron powder particles coated with an electrically insulating layer. These SMCs are then formed into the desired shape by means of a powder metallurgy process.

[0081] During operation of the magnetic levitation device 1, the magnetically active core 31 of the rotor 3 interacts with the stator 2 so that the rotor 3 can be magnetically suspended relative to the stator without contact and preferably can also be magnetically rotated around the axial direction A without contact. In this case, it is particularly advantageous if the same windings 61a, 61b used to achieve the magnetic levitation of the rotor 3 are also used to generate a torque on the rotor 3. Preferably, three degrees of freedom of the rotor 3 can be actively adjusted, namely its position in the radial plane E and its rotation. The magnetically active core 31 of the rotor 3 is passively magnetically stabilized by magnetic resistance with respect to its axial deflection from the radial plane E in the axial direction A, i.e. it cannot be controlled. The magnetically active core 31 of the rotor 3 is also passively magnetically stabilized with respect to the remaining two degrees of freedom, i.e. tilting with respect to the radial plane E perpendicular to the desired axis of rotation. By the interaction of the magnetically active core 31 with the coil core 25, the rotor 3 is thus passively magnetically suspended or passively magnetically stabilized and prevented from tilting in the axial direction A (three degrees of freedom in total) and actively magnetically suspended in the radial plane (two degrees of freedom).

[0082] This is generally the case, and active magnetic suspension is also referred to within the framework of this application as actively controllable or adjustable magnetic suspension, for example by means of an electromagnetic field generated by concentrated windings 61a, 61b. Passive magnetic suspension or passive magnetic stabilization is not controllable or adjustable. Passive magnetic suspension or stabilization is based, for example, on magnetic resistance forces that bring the rotor 3 back to its desired position again when the rotor 3 deviates from its desired position, i.e., for example, when it is displaced or deflected in the axial direction A or when it tilts.

[0083] In contrast to classical magnetic bearings, in the magnetic suspension device 1, magnetic suspension—and optionally the generation of a torque acting on the rotor—is achieved with the aid of an electromagnetic rotating field. For the combined generation of a magnetic suspension force and a torque for rotating the rotor 3 about the axial direction A, on the one hand—such as Figure 1 As shown in FIG. 1 , it is possible to use two different winding systems, namely concentrated windings 61a and concentrated windings 61b, but on the other hand, it is also possible to provide only exactly one concentrated winding 61 on each longitudinal leg 26 (see, for example, FIG. 1 ). Fig.12), which concentrated winding 61 is wound around the respective longitudinal leg 26. This can be implemented, for example, in such a way that the values ​​of the current required for suspension and the values ​​of the current required for generating the torque, which are determined in each case, for example in the control unit 40, are added or superimposed by calculation, for example with the aid of software, and the resulting total current is applied to the respective concentrated winding 61.

[0084] For particularly simple and precise assembly of the magnetic levitation device, two holding devices 8, 9 are provided, namely a first holding device 8 and a second holding device 9, which can be connected to each other. The first holding device 8 comprises a base plate 81, on which a plurality of holding elements 82 are provided, each of which extends from the base plate 81 in the axial direction A. Each holding element 82 is designed such that it can each receive one of the longitudinal legs 26 of the coil core 25 in each case and guide the latter. Preferably, each holding element 82 is designed such that it tightly surrounds the longitudinal leg 26 received by it. The longitudinal leg 26 is thus guided by the holding element 82. The opening 83 ( Fig.11 ) are provided on the base plate 81 so as to be aligned with a retaining element 82 in each case, which receives the first end 261 of the longitudinal leg 26 inserted into the corresponding retaining element 82. Exactly one retaining element 82 is provided for each longitudinal leg 26, so that the number of retaining elements 82 is equal to the number of coil cores 25.

[0085] Each retaining element 82 is designed to be shorter than the longitudinal leg 26 inserted into the retaining element 82 with respect to the axial direction A. Therefore, when the longitudinal leg 26 is fully inserted into the retaining element 82 so that the first end 261 of the longitudinal leg 26 is arranged in the opening 83 in the bottom plate 82, the second end 262 of the longitudinal leg 26 together with the transverse leg 27 arranged thereon protrudes beyond the retaining element 82.

[0086] With respect to the radial direction, each retaining element 82 is arranged in each case between one of the longitudinal legs 26 and the winding 61a, 61b arranged on this longitudinal leg 26 or the winding 61 arranged on this longitudinal leg 26. In particular, if the retaining elements 82 are made of plastic—as is preferred—the retaining elements 82 serve as an insulator between the respective longitudinal leg 26 and the winding 61a, 61b; 61 arranged on this longitudinal leg 26. It is therefore also preferred that the respective retaining element 82 extends in the axial direction A at least as far as the axial end of the winding 61a, 61b; 61 adjacent to the transverse leg 27.

[0087] Preferably, the bottom plate 81 of the first holding device 8 is designed to receive the back iron 22. For this purpose, the bottom plate 81 of the first holding device 8 comprises an annular recess 84 ( Fig.11 ), which is arranged and designed so that the back iron 22 can be inserted into the annular recess 84 and abut against all first ends 261 of the longitudinal legs 26 in the opening 83 of the bottom plate 82.

[0088] The second retaining device 9 is basically designed in a plate-shaped and annular manner and includes a plurality of recesses 91 ( Figure 8 ) for receiving the transverse leg 27 of the coil core 25. Exactly one recess 91 is provided for each transverse leg 27, so that the number of recesses 91 is equal to the number of coil cores 25. The second holding device 9 is inserted into the receiving pot 21 and extends from the bottom of the receiving pot 21 in the axial direction A to the bottom of the receiving pot 21 according to the diagram ( Figure 1 ) is arranged above the retaining element 82 of the first retaining device 8 relative to the axial direction A according to the diagram. This means that the retaining elements 82 of the first retaining device 8 and the second retaining device 9 do not overlap relative to the axial direction A.

[0089] The second holding device 9 is designed in an annular manner such that it can be arranged around the cup-shaped recess 211 of the receiving pot 21 , ie the cup-shaped recess 211 is radially surrounded on the outside by the second holding device 9 .

[0090] The magnetic suspension device 1 further comprises a circuit board 7 with electronic components 71. The circuit board 7 is arranged between the windings 61a, 61b (on the one hand) and the transverse leg 27 (on the other hand) with respect to the axial direction A. The second holding device 9 is designed to receive the circuit board 7. Preferably, the circuit board 7 can be fixed, for example, by means of a plurality of screws 75 (see, for example, Figure 2 ) is attached to the second holding device 9.

[0091] The circuit board 7 is preferably designed as an electronic print or PCB (printed circuit board). For example, a sensor 72 can be arranged on the circuit board, with which the position of the rotor 3 in the cup-shaped recess 211 of the receiving tank 21 or in the radial plane E can be determined. The sensor 72 is designed, for example, as a Hall sensor or an eddy current sensor. In addition, such components can be arranged on the circuit board 7 for controlling the sensor 72 and / or for evaluating the measurement signal determined by the sensor 72.

[0092] The circuit board 7 is designed substantially in annular fashion and is arranged parallel to the radial plane E. Preferably, the circuit board 7 is arranged radially on the inside relative to the longitudinal legs 26 of the coil core 25 so that the electronic component 71 , ie for example the sensor 72 , is arranged around the cup-shaped recess 211 of the receiving pot 21 .

[0093] In the following, reference Figures 5 to 14 Possible embodiments of the various components for the magnetic levitation device 1 are explained in more detail.

[0094] Figure 5A perspective view of one of the coil cores 25 is shown, the coil core having a longitudinal leg 26 extending from a first end 261 to a second end 262 and having a transverse leg 27 arranged at the second end 262 of the longitudinal leg 22. The coil core 25 is designed to be essentially L-shaped, having a rod-shaped longitudinal leg 26 and a transverse leg 27 arranged at right angles thereto. Preferably, the coil core 26 is designed as a sheet metal. In the sheet metal embodiment, each coil core 25 is made of a plurality of thin elements (not shown) stacked parallel to each other. All elements are designed identically, in this case L-shaped, and also have the same thickness in each case.

[0095] Figure 6 A variation of an embodiment for a coil core 26 is shown. In this variation, the longitudinal leg 26 of the coil core 25 has a first section 263 and a second section 264, wherein the first section 263 and the second section 264 are arranged adjacent to each other with respect to the axial direction A. The transverse leg 27 is arranged at the second section 264. The longitudinal leg 26 is designed so that the end face 271 of the transverse leg 27 has a first distance in the radial direction from the first section 263 of the associated longitudinal leg 26, and has a second distance in the radial direction from the second section 264, wherein the second distance is greater than the first distance. This means that the longitudinal leg 26 is designed so that the second section 264 is displaced outwardly in the radial direction relative to the first section 263, so that the space available for accommodating the tank 21 and therefore for the rotor 3 between the end faces 271 is increased, without the risk of magnetic flux passing directly between the longitudinal leg 26 and the magnetically effective core 31 of the rotor 3. Due to the fact that the second section 264 is offset radially outward relative to the radial direction and relative to the first section 263, the distance between the end face 271 in the region of the second section 264 and the longitudinal leg 26 (i.e. the second distance) increases. As a result, the distance between the magnetically active core 31 of the rotor 3 and the longitudinal leg 26 also increases, especially in the region of the second section 264.

[0096] By enlarging the space enclosed by the coil cores 25 in the region of the second section 264 , it is thus possible to use a magnetically active core 31 having a larger diameter without having to increase the diametric distance between the two coil cores 25 in the region of the first end 261 , ie in the region of the back iron 22 .

[0097] Figure 7 A perspective view of a back iron 22 is shown, which is designed essentially in an annular manner and preferably extends radially inwards along the first end 261 of the longitudinal leg 26. Preferably, the back iron 22 is designed as a metal sheet. In the metal sheet embodiment, the back iron 22 is made of a plurality of thin elements 221, which are stacked parallel to each other in the axial direction A. All elements 221 are designed identically, in this case essentially annular, and also have the same thickness.

[0098] The back iron 22 has on its radially outer circumferential surface a plurality of flats 222 which are designed in a planar form, i.e. are not curved. In the assembled state of the stator 2, a first end 261 of one of the longitudinal legs 26, which preferably has a rectangular contour, in each case abuts against each of these flats 222. Due to the planar design of the flats 222, a large contact surface between the back iron 22 and the longitudinal legs 26 of the coil core 25 is ensured, resulting in particularly good flux conduction or very low magnetic resistance at the transition between the back iron 22 and the longitudinal legs 26.

[0099] Preferably, the number of the flat portions 222 is the same as the number of the coil cores 25 , that is, six flat portions 222 are provided here, and these flat portions 222 are equidistantly distributed along the outer periphery of the back iron 22 .

[0100] Furthermore, one or more ventilation holes or ventilation recesses 223 may be provided at the back iron 22 , which extend completely through the back iron 22 with respect to the axial direction A. Air may escape through the ventilation recesses 223 , for example when filling the stator housing 20 with a thermal potting compound.

[0101] Figure 8 A perspective view of a second retaining device 9 is shown with six recesses 91 which receive the transverse legs 27 of the coil core 25. The annularly designed second retaining device 9 has an axial edge region 92 whose outer diameter is smaller than the diameter of the rest of the second retaining device 9. Figure 8 , the axial edge region 92 is the upper axial edge region. Relative to the axial direction A, the axial edge region 92 ends at a projection 93, at which the outer diameter of the second retaining device 9 increases. In this projection 93, several holes 89 are provided - in this case three - which receive screws (not represented) with which the first retaining device 8 and the second retaining device 9 can be attached to each other, so that the two retaining devices 8, 9 are fixed relative to each other.

[0102] The second holding device 9 is preferably made of plastic, and particularly preferably made of plastic that can be processed by injection molding. Therefore, the second holding device 9 is preferably designed as an injection molded part. Suitable plastics for making the second holding device 9 are, for example, acrylonitrile butadiene styrene (ABS), polyamide (nylon, PA), polypropylene (PP) or fiber-filled polypropylene.

[0103] The embodiment of the axial edge region 92 with a smaller diameter and the projection 93 serves to ensure that the receiving pot 21 can radially surround the second retaining device 9 on the outside. This can be seen in particular in Figure 1The receiving pot 21 has a radial outer edge 212 which, in the assembled state, surrounds the axial edge region 92 of the second holding device 9. With respect to the axial direction A, the radial outer edge 212 is designed to be so long that it extends at most as far as the projection 93.

[0104] Fig. 9 A perspective view of an embodiment of a circuit board 7 with electronic components 71 is shown, which include a plurality of—here six—sensors 72. The sensors 72 are, for example, position sensors for determining the current position of the rotor 3 in the cup-shaped recess 211 of the receiving tank 21. The sensors 72 are designed, for example, as Hall sensors or eddy current sensors. Further electronic components 71 (not shown in detail) may also be provided on the circuit board 7, for example components for controlling the sensors 72 or for processing measurement signals.

[0105] The circuit board 7 is designed in an annular manner and has an inner diameter at least as large as the outer diameter of the cup-shaped recess 211 in the accommodating pot 21, so that the circuit board 7 can be arranged radially outward around the cup-shaped recess 211. When viewed in the circumferential direction, the sensors 72 are preferably arranged equidistantly on the circuit board 7. The circuit board 7 further includes several—here three—holes 751 for screws 75, with which the circuit board 7 can be attached to the second holding device 9.

[0106] Fig.10 The top view from the direction of the first end 261 of the coil core 26 onto the second holding device 9 with the circuit board 7 is shown. Figure 1 , the top view is from below. The circuit board 7 is firmly connected to the second holding device 9 by means of three screws 75. The second holding device 9 thus serves as a holder for the circuit board 7, wherein the electronic components 71 or sensors 72 are arranged on the circuit board 7.

[0107] In assembled state (see Figure 1 ), the sensor 72 is therefore arranged in the receiving tank 21 and around the cup-shaped recess 211, wherein the sensor is arranged between the longitudinal leg 26 and the cup-shaped recess 211 with respect to the radial direction.

[0108] Fig.11 A perspective view of the first holding device 8 is shown obliquely from below in the viewing direction, wherein “below” means Figure 1 . Fig.12 A perspective view of the first holding device 8 is shown obliquely from above in the viewing direction, wherein "above" means Figure 1 In the diagram. Fig.12, six concentrated windings 61 are additionally shown, each of which is arranged around exactly one of the holding elements 82. Thus, in this variant, only one concentrated winding 61 is provided in each case on each longitudinal leg 26 of the coil core 25. Of course, exactly two concentrated windings 61a, 61b are provided on the holding element 8 (see, for example, Figure 4 ) embodiments are also possible.

[0109] The first holding device 8 with the base plate 81 and the plurality of holding elements 82 is preferably designed as one piece. The first holding device 8 is preferably made of plastic, and particularly preferably made of plastic that can be processed by injection molding. Therefore, the first holding device 8 is preferably designed as an injection molded part. Suitable plastics for manufacturing the first holding device 8 are, for example, acrylonitrile butadiene styrene (ABS), polyamide (nylon, PA), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), polysuccinimide (PSI), polyphthalamide (PPA) or polyetheretherketone (PEEK), wherein glass fibers, carbon fibers, aramid fibers, ceramic fibers or fibers made of other materials are preferably added to the plastic to improve the mechanical properties.

[0110] For each coil core 25, the first holding device 8 comprises in each case exactly one holding element 82. The number of holding elements is equal to the number of coil cores 25. Each holding element 82 is preferably designed with a plurality of rods 821, wherein the free space 822 is provided between adjacent rods. Each of the rods 821 extends in the axial direction A in each case. The rods 821 of the holding element 82 are designed and arranged so that the longitudinal legs 26 received by the holding element 82 are reliably guided and held. Preferably, the rods 821 are designed so that they exert a spring force on the longitudinal legs 26 received by the respective holding element 82, i.e., when the longitudinal legs 26 are inserted, the rods 821 are elastically deformed by the spring. In this way, when the longitudinal legs 26 are inserted into the holding element 82, the rods 821 reliably guide the longitudinal legs 26 so that the first ends 261 of the longitudinal legs 26 can be inserted into the openings 83 in the bottom plate 81 in a simple and reliable manner.

[0111] In the embodiment described here, the longitudinal legs 26 of the coil core 25 each have a rectangular profile in a section perpendicular to the axial direction A. Then, one rod 821 is preferably provided for each edge of the longitudinal leg 26, at which edge the rod 821 is arranged. Thus, each retaining element 82 comprises exactly four rods 821, which are arranged at the four edges of the longitudinal leg 26. Particularly preferably, each rod 821 is designed with an angled profile in a section perpendicular to the axial direction A, wherein the edge of the longitudinal leg 26 rests in the angled profile of the rod 821. This embodiment of the rod 821 can be Fig.12Thus, each rod 821 with an angled profile encompasses one of the edges of the longitudinal leg 26. In this way, the longitudinal leg 26 is reliably guided at its edges, since each of these edges is encompassed by one of the rods 821 with an angled profile.

[0112] In perspective, Fig.13 Show Figure 4 The receiving tank 21 of the stator 2 of the embodiment presented in FIG. Fig.14 The container 21 is shown in a cross-sectional view, wherein the section is taken in the axial direction.

[0113] The holding tank 21 with the cup-shaped recess 211 is preferably designed as one piece. The holding tank is preferably made of plastic, and is particularly preferably made of plastic that can be processed by injection molding. Therefore, the container tank is preferably designed as an injection molded part. Suitable plastics for making the holding tank 21 are, for example, acrylonitrile-butadiene-styrene (ABS), polyamide (nylon, PA), polypropylene (PP), polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane (PFA), polyvinyl chloride (PVC), polybutylene terephthalate (PBT), polyimide (PI), polyetherketone, polysuccinimide (PSI), polyphthalamide (PPA) or polyetheretherketone (PEEK).

[0114] The receiving pot 21 comprises a cup-shaped recess 211 into which the rotor 3 can be inserted and a radial outer edge 212 which surrounds the axial edge region 92 of the second retaining device 9 in the assembled state.

[0115] The magnetic levitation device 1 can be assembled in a very simple manner. For example, the assembly can be carried out as follows. The back iron 22 is inserted into the annular recess 84 in the bottom plate 81 of the first holding device 8. The windings 61a and 61b or 61 are placed on the holding element 82. The circuit board 7 is fixed to the second holding device 9 by means of screws 75. The first holding device 8 and the second holding device 9 are connected to each other by means of screws (not shown). The coil cores 25 are inserted into the holding element 81 of the first holding device 8 through the second holding device 9 so that their first ends 261 are received by the opening 83 in the bottom plate 81 of the first holding device 8. The whole consisting of the two holding devices 8, 9, the windings 61a, 61b; 61 and the coil core 25 is placed in the stator housing 20.

[0116] Alternatively, it is also possible to first place the first retaining device 8 with the inserted back iron 22 in the stator housing 20, then arrange the windings 61a, 61b; 61 on the retaining element 81, arrange the second retaining device 9 with the circuit board 7 fixed to it in the stator housing 20 and connect it to the first retaining device 8, and then insert the coil core 25 into the retaining element 82 through the second retaining device 9.

[0117] When the two holding devices 8, 9, the windings 61a, 61b; 61 and the coil core 25 are arranged in the stator housing 20, the receiving pot 21 is placed on the stator housing 20 and connected to the stator housing 20 in a sealed manner (preferably a gas-tight sealed manner). Subsequently, the magnetic suspension device can be filled with a thermally conductive potting compound so that the entire space enclosed by the stator housing 20 and the receiving pot 21 is filled with the potting compound.

[0118] In addition, the present invention provides a centrifugal pump 100 for conveying a fluid, characterized in that the centrifugal pump 100 comprises a magnetic levitation device 1 and a rotor 3, wherein the magnetic levitation device 1 is designed according to the present invention. The magnetic levitation device 1 is designed so that in addition to the non-contact magnetic levitation of the rotor 3, it can generate a torque acting on the rotor 3, which drives the rotor 3 to rotate around the axial direction A.

[0119] In a schematic cross-sectional view showing a section along the axial direction A, Fig.15 An embodiment of a centrifugal pump according to the invention is shown, which is designated in its entirety by the reference symbol 100. For better understanding and for reasons of a better overview, Fig.15 The stator housing 20 and the accommodating tank 21 are not shown.

[0120] The centrifugal pump 100 comprises a pump unit 50 having a pump housing 51, which comprises an inlet 52 and an outlet 53 for the fluid to be conveyed, wherein the rotor 3 is arranged in the pump housing 51 and comprises a plurality of blades 54 for conveying the fluid. The pump unit 50 is designed such that the pump unit 50 can be inserted into the receiving pot 21 of the stator 2 so that the magnetically active core 31 of the rotor 3 is surrounded by the end faces 271 of the transverse legs 27.

[0121] Advantageously, the rotor 3 is designed as an integral rotor, since it is both the magnetically suspended rotor 3 and the rotor 3 of the centrifugal pump 100 with which the fluid is conveyed. This embodiment as an integral rotor offers the advantage of a very compact and space-saving design.

[0122] The stator 2 is arranged in the stator housing 20 ( Fig.15 In the embodiment (not shown), the stator housing 20 is preferably designed together with the receiving tank 21 as a hermetically sealed stator housing 20. Figure 1 The control unit 40 presented in FIG is preferably, but not necessarily, also arranged in the stator housing 20. The stator housing 20 is preferably filled with a potting material (eg, with epoxy resin or with polyurethane) so that all components arranged inside the stator housing 20 are surrounded by the potting material.

[0123] The pump unit 50 is arranged in the cup-shaped recess 211 of the storage tank 21 ( Fig.15), so that the rotor 3 arranged in the pump housing 51 is surrounded by the cup-shaped recess 211 , wherein the magnetically effective core 31 of the rotor 3 is arranged between the transverse legs 27 of the coil core 26 .

[0124] The pump housing 51 is preferably fixed to the stator housing 20 by means of a plurality of screws (not shown).

[0125] The rotor 3 comprises a plurality of blades 54 for conveying a fluid. For example, in the embodiment described here, a total of four blades 54 are provided, whereby this number has an exemplary feature. The rotor 3 further comprises a sheath 38, and the magnetically effective core 31 of the rotor 3 is surrounded by the sheath 38 and preferably hermetically sealed so that the magnetically effective core 31 of the rotor 3 does not contact the fluid to be conveyed. All blades 54 are arranged on the sheath 38 and are arranged equidistantly relative to the circumferential direction of the rotor 3. Each blade 54 extends outwardly in the radial direction and is connected to the sheath 38 in a torque-proof manner. The blades 54 may be separate components, which are then fixed to the sheath 38. Of course, it is also possible that all blades 54 are components of the sheath 38, that is, the sheath 38 is designed as one piece with all blades 54. The rotor 3 with blades 54 forms a wheel or impeller of a centrifugal pump 100, with which one or more streams of fluid act on it.

[0126] Depending on the application, it is preferred if the pump housing 51 of the pump unit 50 as well as the jacket 38 and the blades 54 are made of one or more plastics. Suitable plastics are: polyethylene (PE), low-density polyethylene (LDPE), ultra-low-density polyethylene (ULDPE), ethylene vinyl acetate (EVA), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polypropylene (PP), polyurethane (PU), polyvinylidene fluoride (PVDF), acrylonitrile butadiene styrene (ABS), polyacrylate, polycarbonate (PC), polyether ether ketone (PEEK) or silicone. For many applications, materials with the brand names Teflon, polytetrafluoroethylene (PTFE) and perfluoroalkoxy polymers (PFA) are also suitable as plastics.

[0127] It will be appreciated that the magnetic levitation device according to the invention is also suitable for use in devices other than centrifugal pumps, such as mixing devices for mixing flowable substances, for stirring devices (e.g. for mixing fluids in tanks), for fans, or also for devices for supporting and rotating wafers (e.g. in semiconductor production).

Claims

1. A magnetic suspension device for non-contact magnetic suspension of a rotor (3), the rotor (3) comprising a disc-shaped or annular magnetic active core (31), wherein: The magnetic levitation device has a stator (2), the stator (2) comprising a plurality of coil cores (25), each of the coil cores (25) comprising a longitudinal leg (26) extending from a first end (261) to a second end (262) in an axial direction (A), and a transverse leg (27) arranged at the second end (262) of the longitudinal leg and extending in a radial direction perpendicular to the axial direction (A), wherein at least one concentrated winding (61a, 61b; 61) is provided at each longitudinal leg (26), the winding surrounding the corresponding longitudinal leg (26), wherein the stator (2) further comprises a cup-shaped recess (211), wherein the rotor (3) can be inserted into the cup-shaped recess (211), wherein the cup-shaped recess The stator (2) is provided with a cup-shaped recess (211) 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 a first retaining device (8) and a second retaining device (9) are provided, the first retaining device (8) and the second retaining device (9) being connectable to each other, wherein the first retaining device (8) comprises a base plate (81), a plurality of retaining elements (82) are arranged on the base plate (81), each of the retaining elements (82) extends in the axial direction (A), and each of the retaining elements (82) is designed to receive exactly one of the longitudinal legs (26), and wherein the second retaining device (9) is designed to receive the transverse leg (27).

2. The magnetic levitation device according to claim 1, wherein: The stator (2) has a receiving pot (21) which forms an axial end of the stator (2), and wherein the receiving pot (21) has the cup-shaped recess (211) into which the rotor (3) can be inserted.

3. A magnetic levitation device according to any one of the preceding claims, having an annular back iron (22) for conducting magnetic flux, the annular back iron (22) connecting the first ends (261) of all longitudinal legs (26), wherein: The bottom plate (81) of the first retaining device (8) is designed to receive the back iron (22), and wherein the back iron (22) is preferably arranged radially inwardly at the first end (261) of the longitudinal leg (26).

4. A magnetic levitation device according to any one of the preceding claims, wherein: A circuit board (7) with electronic components (71) is arranged between the winding (61a, 61b; 61) and the transverse leg (27) with respect to the axial direction (A), and wherein the second retaining device (9) is designed to receive the circuit board (7).

5. The magnetic levitation device according to claim 4, wherein: The circuit board (7) is designed in a ring-shaped manner and is arranged such that the electronic component (71) is arranged around the cup-shaped recess (211).

6. The magnetic levitation device according to any one of claims 2 to 5, wherein: The receiving pot (21) surrounds the second holding device (9) radially outwardly.

7. A magnetic levitation device according to any one of the preceding claims, wherein: Each retaining element (82) of the first retaining device (8) is arranged in each case between one of the longitudinal legs (26) and the winding (61a, 61b; 61) arranged on the longitudinal leg (26) with respect to the radial direction, and extends with respect to the axial direction (A) at least to the ends of all windings (61a, 61b; 61) arranged on the corresponding longitudinal leg (26).

8. A magnetic levitation device according to any one of the preceding claims, wherein: Each retaining element (82) comprises a plurality of rods (821) with empty spaces (822) located between them, wherein each rod (821) extends in said axial direction (A).

9. The magnetic levitation device according to claim 8, wherein: The rods (821) of the retaining elements (82) are arranged and designed in such a way that they exert a spring force on the longitudinal legs (26) received by the respective retaining element (82).

10. The magnetic levitation device according to any one of claims 8 to 9, wherein: Each longitudinal leg (26) has a rectangular cross-section perpendicular to the axial direction (A), and wherein exactly one of the rods (821) is arranged at each corner of the longitudinal leg (26).

11. A magnetic levitation device according to any one of the preceding claims, wherein: The first holding device (8) or the second holding device (9) is made of plastic.

12. The magnetic levitation device according to any one of claims 2 to 11, wherein: The containing tank (21) is made of plastic.

13. A magnetic levitation device according to any one of the preceding claims, wherein: The control unit (40) is arranged for controlling the windings (61a, 61b; 61) and for supplying the windings (61a, 61b; 61) with electrical energy for generating an electromagnetic field.

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

15. A centrifugal pump for conveying fluid, characterized in that: The centrifugal pump comprises a magnetic levitation device (1) according to claim 14, and a rotor (3) with a magnetically active core (31), wherein the rotor (3) can be inserted into a cup-shaped recess (211) of a receiving tank (21), and wherein the rotor (3) is designed as a rotor (3) of the centrifugal pump.

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