Magnetic levitation device and pump unit

Abstract

A magnetic levitation device for non-contact magnetic levitation of a rotor (3) is proposed, wherein the magnetic levitation device comprises a stator (2) having a cup-shaped recess (211) into which the rotor (3) can be inserted, the stator (2) comprises a back iron (28), and the stator (2) comprises a plurality of stator poles (25) each having a connecting leg (26) and a pole piece (27), each connecting leg (26) extends from a first end (261) to a second end (262), the first end (261) contacts the back iron (28), each pole piece (27) has a contact surface (271), each pole piece (27) extends radially (r) from the contact surface (271) to an end surface (272), all end surfaces (272) are arranged around the cup-shaped recess (211), and at least one concentration A winding (61) is positioned in each radial part (282), and each connecting leg (26) extends radially inward from the first end (261) diagonally with respect to the axial direction (a) to the second end (262), so that the back iron surface (285) and the pole piece surface (273) are positioned to have an offset (v) with respect to the axial direction (a). Furthermore, a pump unit for such a magnetic levitation device is proposed.

Description

Technology Field

[0001] The present invention relates to a magnetic levitation device according to the preamble of an independent claim and a pump unit having such a magnetic levitation device. Background Technology

[0002] Magnetic levitation devices for non-contact magnetic levitation of the rotor have the advantage of operating without mechanical bearings for the rotor. The rotor is levitated or stabilized by the magnetic force generated by the stator of the magnetic levitation device. Because there are no mechanical bearings, these magnetic levitation devices are particularly suitable for use in pumping, mixing, centrifugation, or stirring devices where very sensitive materials are transported, for example, blood pumps, or where very high purity is required, for example, in the pharmaceutical or biotechnology industries, or with pumps or mixers for slurries, sulfuric acid, phosphoric acid, or other chemicals in the semiconductor industry, where abrasive or aggressive materials that can rapidly destroy mechanical bearings are transported.

[0003] In the biotechnology industry, these magnetic levitation devices are used in connection with bioreactors, for example, in the case of centrifugal pumps for introducing or discharging fluids into or out of a bioreactor, or in the case of mixing devices for mixing fluids within a bioreactor. In the semiconductor industry, these magnetic levitation devices are used not only for the transport of aggressive or abrasive materials, but also, for example, in rotating devices for rotating wafers.

[0004] It is also known that magnetic levitation devices are used for viscometers.

[0005] One preferred and known configuration of a magnetic levitation device is a temple construction. Such a magnetic levitation device is illustrated in FIG. 1. Reference numerals in FIG. 1 are each enclosed in quotation marks to indicate that these components belong to the prior art.

[0006] A feature of the temple structure is that the stator (2′) of the magnetic levitation device (1′) has a plurality of coil cores (25′), and each coil core includes a longitudinal leg (26′) extending from a first end (261′) to a second end (262′) in the axial direction (A′). In this case, the axial direction (A′) refers to a direction defined by the desired rotation axis of the rotor (3′) that is levitating by the magnetic levitation device (1′). The desired rotation axis is the rotation axis on which the rotor (3′) rotates in the operating state when it is centered and not tilted with respect to the stator (2′). Each coil core (25′) includes, in addition to the longitudinal leg (26′), a transverse leg (27′), i.e., a pole piece, which is positioned at the second end (262′) of the longitudinal leg (26′) and extends radially (R′), typically inwardly, and the radial direction (R′) is perpendicular to the axial direction (A′). Thus, the transverse leg (27′) extends substantially perpendicularly to the longitudinal leg (26′). Each coil core (25′) has an L shape, wherein the transverse leg (27′) forms a short leg of L. The rotor (3′) to be lifted is now positioned between the transverse legs (27′).

[0007] Multiple longitudinal legs (26′) that extend in the axial direction (A′) and resemble the pillars of a temple give this structure its name.

[0008] In one example configuration illustrated in FIG. 1, the stator (2′) of the magnetic levitation device (1′) has, for example, six coil cores (25′), which are arranged in a circular and equal spacing around a cup-shaped recess into which a rotor (3′) can be inserted, although not explicitly shown in FIG. 1. The first end of the longitudinal leg is typically connected circumferentially by a back iron (28′) for transmitting magnetic flux. The rotor (3′) to be levitized comprises a magnetic active core (31′), for example, a permanent magnet disk or a permanent magnet ring, which is positioned between the radially inner ends of the transverse leg (27′) and rotates about the axial direction (A′) in the operating state, wherein the rotor (3′) is magnetically levitized non-contactually with respect to the stator (2′).

[0009] In the case of such a magnetic levitation device (1′), the magnetic active core of the rotor (31′) does not necessarily have to be a permanent magnet structure. Such a design is also known in which the magnetic active core (31′) of the rotor (3′) is designed without a permanent magnet, that is, not to include a permanent magnet. In such a case, the magnetic active core of the rotor (31′) is formed of, for example, a ferromagnetic material and is composed of, for example, iron, nickel-iron, cobalt-iron, silicon-iron, mu-metal, or other ferromagnetic materials.

[0010] Furthermore, a design in which the magnetic active core of the rotor (31') includes both ferromagnetic and permanent magnetic materials is also possible. For example, a permanent magnet may be placed or inserted within the ferromagnetic body. This design is advantageous when it is intended to reduce costs by reducing the amount of permanent magnet material, for example in the case of a large rotor.

[0011] To generate the electromagnetic field necessary for non-contact magnetic levitation of the rotor (3′), the longitudinal leg (26′) has a winding (61′). The winding (61′) is designed such that, for example, a concentrated winding (61′) is wound around each longitudinal leg (26′), that is, the coil axis of each concentrated winding (61′) extends in the axial direction (A′). In this case, with respect to the temple structure, the coil axis of the concentrated winding (61′) extends in the axial direction (A′), and it is customary that the concentrated winding (61′) is not positioned within the radiation plane (R′) where the magnetic active core of the rotor (3′) or rotor (31′) levitizes in the operating state.

[0012] A design is possible in which exactly one concentrated winding (61′) is placed on each longitudinal leg (26′). In other designs, multiple, for example, exactly two concentrated windings (61′) are provided on each longitudinal leg (26′). Additionally, a design is possible in which a winding (61′) is provided around two circumferentially adjacent longitudinal legs (26′), so that as a result, both of these two adjacent longitudinal legs (26′) are located inside the concentrated winding (61′).

[0013] The temple structure described immediately above enables a well-verified magnetic levitation device (1′) that is known from the prior art but still has potential for improvement. In the case of a magnetic levitation device (1′) with a temple structure, it is difficult to design them to be sufficiently compact. The longitudinal leg (26′) and the concentrated winding (61′) are required for the operation of the magnetic levitation device (1′) with a temple structure. However, these simultaneously predetermine the spatial size of the device. Therefore, it is not easily possible to use such a magnetic levitation device (1′) in applications where the available space for the magnetic levitation device (1′) is small, for example, due to spatial constraints. Conversely, this means that the magnetic levitation device (1′) with a temple structure cannot be designed to be sufficiently compact for reliable operation in some applications, or it is only possible at a high cost.

[0014] The non-compact structure of the magnetic levitation device (1′) also requires a large amount of material for the manufacture of individual components. Therefore, the entire device (1′) has a high weight and higher cost, which again may make the device unsuitable for some applications.

[0015] Furthermore, designing a temple-structured magnetic levitation device (1′) having more than six coil cores (25′) is often a difficult task. If the size of the rotor (3′) or the magnetic active core (31′) cannot be changed, for example, it is difficult to place two additional coil cores (25′) around the cup-shaped recess (211′). Furthermore, because the available space is small, the longitudinal legs (26′) are placed very close to each other, which can cause leakage flux and thus lead to high iron loss. Another problem that can lead to high iron loss is that a long magnetic path is created due to the structure of the longitudinal legs (26′). However, these are undesirable because the generated loss must ultimately be released in the form of heat, and thus the efficiency of the temple-structured magnetic levitation device is reduced. The problem to be solved

[0016] Starting from such prior art, the objective of the present invention is to propose a magnetic levitation device for non-contact magnetic levitation of a rotor having a disc-shaped or ring-shaped magnetic active core, wherein the magnetic levitation device has a more compact structure while simultaneously having higher efficiency.

[0017] Furthermore, another objective of the present invention is to propose a pump unit having such a magnetic levitation device.

[0018] The technical gist of the present invention satisfying these objectives is characterized by the features of the independent claim. means of solving the problem

[0019] Accordingly, according to the present invention, a magnetic levitation device for non-contact magnetic levitation of a rotor having a disc-shaped or ring-shaped magnetic active core is proposed, and the magnetic levitation device comprises a stator having a cup-shaped recess that extends axially and is disposed at a first axial end of the stator and into which the rotor can be inserted. The stator further comprises a back iron, the back iron having a plurality of radial portions, at least one circumferential portion, a back iron bottom face, and a back iron surface, each radial portion extending radially from the circumferential portion perpendicular to the axial direction, the back iron surface facing the first axial end of the stator, and the back iron bottom face facing the second axial end of the stator. The stator comprises a plurality of stator poles, each stator pole having a connecting leg and a pole piece, each connecting leg extending from a first end to a second end, the first end in contact with the back iron. Each pole piece has a contact surface that contacts a second end of a connecting leg, and each pole piece extends radially from said contact surface to an end face, and all end faces are arranged around a cup-shaped recess. At least one concentrated winding is arranged on each radial part, and such winding surrounds the individual radial part. Each connecting leg extends radially inward from a first end at an angle with respect to the axial direction to a second end, so that the back iron surface and the pole piece surface of the pole piece are arranged with an offset with respect to the axial direction.

[0020] That the connecting leg extends radially inward means that the second end of the connecting leg is at a smaller distance from the cup-shaped recess than the first end. That the connecting leg extends obliquely with respect to the axial direction means that the axis of the connecting leg forms an angle greater than 0° and less than 90° with respect to the axial direction. The angle is preferably 20° to 60°. Particularly preferably 30° to 55°. The axis of the connecting leg that forms an angle with the axial direction preferably extends from the first center point of the first contact surface of the connecting leg to the second center point of the second contact surface of the connecting leg, and the second contact surface is positioned on the contact surface of the pole piece.

[0021] The axial offset must be greater than 0% and less than 100% of the axial height of the pole piece, wherein the axial height of the pole piece defines the extension in the axial direction. The offset is preferably 5% to 75% of the axial height, and particularly preferably 15% to 45%.

[0022] The arrangement of the pole piece for the back iron can also be described in terms of planes. The back iron surface is located within one radial plane, and the pole piece surface is located within another radial plane parallel to it. The two planes are at a distance corresponding to an offset from each other in the axial direction. The normal vectors of the two planes are preferably positioned parallel to the axial direction.

[0023] In the context of this application, a cup-shaped recess is understood to mean a recess resembling the shape of a cup. That is, the cup-shaped recess has at least one diameter in the radial direction. The external shape of the cup-shaped structure may be cylindrical, conical, or otherwise composed of a combination of these two shapes. The cup-shaped recess may have both a closed bottom and an open bottom, or it may not have a bottom. It is evident that the cup-shaped recess may also have smaller artifacts, such as openings or recesses, for example.

[0024] This design of the magnetic levitation device is advantageous because it enables a compact magnetic levitation device as a result. It is also advantageous that a greater number of stator poles can be arranged around a cup-shaped recess under substantially the same space requirements as in the case of a temple motor known from the prior art. This ensures that the corresponding surface of the rotor facing the end face of the pole piece when viewed from the circumferential direction is more widely covered by the stator poles. Consequently, better magnetic flux transmission of the magnetic field is achieved.

[0025] Furthermore, it is advantageous that a flat surface of the stator is achieved at the axial top of the stator as a result of the pole piece being offset relative to the back iron. In the absence of an offset, at least one concentrated winding positioned on each radial portion of the back iron has an axial extension, so the surface of the concentrated winding is positioned axially over the back iron surface, and thus no flat surface would exist. In other words, the stator housing surrounding the stator thus has a flat surface at the axial top of the stator. Put differently, the axial top surface of the stator housing is located within a single radial plane. This is advantageous for magnetic levitation devices because better interaction between the stator and the rotor is consequently achieved. The rotor or magnetic active core has a radial center plane that coincides with the radial center plane of the pole piece. That is, when inserted into a cup-shaped recess, the axial position of the rotor is determined by the axial position of the pole piece. Due to the offset between the pole piece and the back iron, the rotor is therefore lifted as high as possible axially with respect to the axial upper surface of the stator housing, that is, further away from the second end of the stator in the axial direction. By lifting the rotor as high as possible axially in this way, the rotor can be designed to be more compact, and as a result, the stability of the rotor's levitation within the stator is improved.

[0026] This is particularly advantageous when the magnetic levitation device is intended for the levitation of a rotor in which at least one vane is positioned. Such a rotor is used, for example, for fluid pumps and / or mixers. In such applications, if the rotor is lifted to its maximum height, at least one vane may have a smaller axial extension, and as a result, a force acting more upwardly in the axial direction on the vane or rotor is prevented. As a result, the tilting moment is reduced, and the levitation of the rotor is ensured well and reliably.

[0027] In addition, in the case of centrifuges, rotary filters, or cross-flow fans, it is possible to use two magnetic levitation devices according to the present invention, or a combination of a magnetic levitation device according to the present invention and another magnetic levitation device, for the joint levitation of the rotor at both ends of the rotor. In such applications as well, the rotor can be advantageously designed to be short by means of the magnetic levitation device according to the present invention, which additionally advantageously increases the flexural resonance frequency of the rotor and shifts it outside the operating frequency range.

[0028] In the case where there is no offset between the pole piece and the back iron, the rotor is positioned axially lower, that is, closer to the second axial end of the stator in the axial direction, and as a result, a force that interferes with the operation of the magnetic levitation device acts on the rotor above the radial center plane when viewed axially. This is disadvantageous because it consequently generates a larger torque, which ensures that the rotor tilts. This then reduces the stability of the rotor's mounting within the stator.

[0029] In a preferred embodiment, the back iron comprises a plurality of segments, and each segment has a radial portion and a circumferential portion. That is, in this embodiment, the number of segments corresponds to the number of radial portions and the number of circumferential portions. The number of segments is preferably 12. However, embodiments with a smaller number, such as, for example, 6 or 8, or a larger number, such as, for example, 16 or 20, are also possible.

[0030] In a preferred embodiment, all segments of the back iron are arranged to be in contact with each other.

[0031] In a preferred embodiment, all segments of the back iron are arranged to be in contact with each other without any gaps.

[0032] Each segment has a first segment end and a second segment end in the circumferential direction. In a preferred embodiment, the segment has a first shape at the first segment end and a second shape at the second segment end, and the first shape and the second shape are complementary shapes. In other words, the first shape is a male shape and the second shape is a female shape, corresponding shapes.

[0033] This means that the two shapes are designed such that the end of the first segment can be connected to the end of the second segment of the first adjacent segment in a shape-interlocking manner, and the end of the second segment can be connected to the end of the first segment of the adjacent second segment in a shape-interlocking manner. Accordingly, the first shape and the second shape are designed as two geometric shapes that interlock with each other.

[0034] According to a preferred embodiment, the first shape and the second shape have a circular, semicircular, or elliptical design. However, other geometric shapes are also possible.

[0035] These embodiments have the advantage of providing a certain degree of flexibility when combining individual segments, so that, for example, they can be moved relative to each other when necessary. This also facilitates the replacement of individual segments.

[0036] According to a preferred embodiment, the first shape and the second shape have a stepped shape in the axial direction, and the steps at the first segment end and the second segment end are complementary to each other.

[0037] In a preferred embodiment, the stator has 12 stator poles, and the rotor has a plurality of rotor poles, preferably 8 rotor poles, and the rotor poles are configured as 4 pole pairs.

[0038] In the case of an embodiment where the back iron is not divided, all 12 stator poles are placed on a single back iron. The number of 12 stator poles should be understood as merely exemplary, and there may be more or fewer stator poles than 12.

[0039] In the case of an embodiment having a divided back iron, this preferably means that there are 12 back iron segments in which 12 stator poles are arranged. In other words, in this case, it is preferable that one stator pole always forms one segment and one unit, and that these units are arranged circumferentially to form a back iron in which a stator pole is arranged thereon.

[0040] However, it is also possible to have two or more stator poles arranged on a single back iron segment. Thus, for example, in this embodiment, six segments can form a stator having 12 stator poles, and two stator poles are arranged on each segment.

[0041] The number of stator poles and rotor poles may also be fewer or more than the previously mentioned 12 stator poles or 8 rotor poles. Likewise, the number of stator poles per segment may be more or fewer than the previously mentioned 2 stator poles.

[0042] In a preferred embodiment, the segment and the pole piece each have an axial thickness in the axial direction, and these two axial thicknesses have the same size, and the axial distance between the back iron bottom face and the pole piece surface is greater than the axial thickness.

[0043] Furthermore, it is desirable that the bottom surface of the back iron and the bottom surface of the pole piece are not located within the same radial plane but are offset from each other, while the surface of the pole piece is positioned closer to the axial top of the stator than the back iron surface in the axial direction.

[0044] In a preferred embodiment, the back iron bottom surface and the back iron surface are each positioned within a plane positioned perpendicular to the axial direction.

[0045] In a preferred embodiment, the segments form a continuous and / or composite ring that forms a back iron, and the ring is positioned perpendicular to the axial direction (A).

[0046] According to a preferred embodiment, at least one concentrated winding is in a conical configuration.

[0047] In this case, regarding the conical winding, all types of windings known to those skilled in the art from the prior art are possible, and, for example, stepped conical windings are also possible. Likewise, all winding techniques known from the prior art that possess good manufacturability and achieve high compactness and high filling rate through a layered structure are also considered. Examples include orthocyclic windings, conductor cross-section designs such as circular, flat, or square wires, and the arrangement of the winding start and end sections. Accordingly, the winding strands can also be wired in series or parallel and optionally twisted. Corresponding insulation measures, such as coil holders and insulation layers, are also obvious.

[0048] Furthermore, at least one concentrated winding has a radial first end and a radial second end, wherein the radial first end faces a circumferential portion and the radial second end faces a cup-shaped recess, and the at least one concentrated winding has a first outer diameter at the radial first end and a second outer diameter at the radial second end, and it is preferable that the first outer diameter is larger than the second outer diameter.

[0049] This embodiment of at least one concentrated winding is advantageous for the compactness of the magnetic levitation device. Thus, the stator poles can be arranged more flexibly.

[0050] Particularly preferably, a plurality of concentrated windings, in particular all concentrated windings, are designed such that each individual concentrated winding has a first outer diameter at a radial first end and a second outer diameter at a radial second end, and in each case, the first outer diameter is larger than the second outer diameter.

[0051] In a preferred embodiment, the end face of the pole piece is configured as a curved surface. In particular, it is preferable that the rounding of the end face be configured coaxially with respect to the cup-shaped recess. In other words, the end face of the pole piece is part of a cylindrical surface, the central axis of this cylinder coincides with the central axis of the cup-shaped recess, and the radius of this cylinder is larger than the radius of the cup-shaped recess so that the end face does not protrude into the cup-shaped recess.

[0052] In a preferred embodiment, the end face is configured to be wider in the circumferential direction than the maximum extension of the contact surface in the circumferential direction. This means that one of the two edges of the end face extending in the circumferential direction is longer than one of the edges of the contact surface extending in the circumferential direction. If the end face is configured as a curved surface, the length of one of the arcs of the segment of the cylindrical surface in the radial plane is longer than the length of one of the edges of the contact surface extending in the circumferential direction.

[0053] Extending the end face in the circumferential direction in this way has advantages because it improves magnetic functionality. For example, passive rigidity and active levitation force can be improved.

[0054] According to an additional preferred embodiment, the end face is configured to be narrower in the circumferential direction than the circumferential maximum extension of the contact surface. This means that one of the two edges of the circumferentially extending end face is shorter than one of the edges of the circumferentially extending contact surface.

[0055] According to a preferred embodiment, the segment is manufactured by a lamination method from back iron elements, and the back iron elements are laminated in the axial direction.

[0056] According to an additional preferred embodiment, the connecting leg is manufactured by laminating elements, and the elements are laminated in the circumferential direction of the stator.

[0057] Likewise, according to a preferred embodiment, the pole piece is manufactured in a stacking manner from pole elements, and the pole elements are stacked axially.

[0058] One advantage of the stacked design is that the reduction of eddy current losses in the corresponding components (segments, connecting legs, pole pieces) is guaranteed.

[0059] Most eddy current losses occur in the pole pieces, because the distance between adjacent pole pieces is particularly short, especially at the end facing the cup-shaped recess. This applies particularly to embodiments where the end face is configured to be wider than the maximum circumferential extension of the contact surface in the circumferential direction. This is because eddy current losses are mainly generated from orthogonal magnetic fields, that is, magnetic fields penetrating the pole elements in an orthogonal direction. In particular, when the distance between pole pieces is short, such orthogonal magnetic fields have the potential to flow circumferentially from the pole piece of the first stator pole to the pole piece of the adjacent second stator pole. Eddy currents caused by orthogonal magnetic fields in the circumferential direction are prevented by the pole elements of the axially stacked pole pieces. Thus, eddy current losses are significantly reduced.

[0060] As a result, additional significant advantages are obtained. Since the magnetic field flowing circumferentially from the pole piece of the first stator pole to the pole piece of the adjacent second stator pole flows parallel to the axially stacked pole elements and thus does not generate eddy current losses, the end faces of the pole pieces can be positioned closer to each other in the circumferential direction. Thus, for example, passive stiffness and active levitation can be improved and / or a more compact structure of the stator is possible.

[0061] In a preferred embodiment, the pole piece is manufactured from a soft magnetic material. In this case, the pole piece and / or segment and / or connecting leg is preferably manufactured from electrical steel. By general definition, electrical steel is understood to mean a soft magnetic material for a magnetic core. Soft magnetic materials are typically referred to as materials having low coercivity. Coercivity is the magnetic field strength required to demagnetize a material. In the context of this application, soft magnetic materials are understood to mean materials with a coercivity, more precisely, a coercivity of magnetic polarization, of less than 2000 A / m². Additional suitable soft magnetic materials for stator poles and back irons are, for example, ferromagnetic or ferrimagnetic materials, namely, iron, nickel-iron, cobalt-iron, silicon-iron, or mu-metal.

[0062] Changing the orientation of the stacked design between individual components (segments, connecting legs, pole pieces) once again ensures an additional reduction in eddy current losses of the entire magnetic levitation device.

[0063] In a preferred embodiment, the back iron elements are stacked axially (i.e., stacked axially), the connecting leg placed thereon now has elements stacked circumferentially, and the pole piece placed thereon now has pole elements stacked axially. These changes in placement and orientation ensure that losses in the magnetic levitation device are reduced.

[0064] Elements of connecting legs stacked circumferentially have the advantage of lower losses in this case and reduced magnetic resistance compared to when the connecting leg elements are stacked axially. This is because, in the case of circumferentially stacked elements, the magnetic field does not need to pass through the stacking planes in the axial direction. In other words, conversely, if the connecting legs are stacked axially, the magnetic field will flow axially along the boundary between adjacent stacking planes, resulting in losses and increased magnetic resistance.

[0065] As a result of the offset between the segment and the pole piece and the consequent axial rise of the rotor, the arrangement in which the elements of the connecting leg are stacked circumferentially is advantageous because the elements can transmit a magnetic field in both the radial and axial directions.

[0066] Furthermore, pole pieces and / or connecting legs can be manufactured from powder composite materials, particularly soft magnetic powder composite materials. In this case, the material referred to as a "soft magnetic composite (SMC)" may be high-purity iron powder with a specific surface coating. In this case, the specific surface coating is electrically insulating. SMCs are primarily known for their application in the transmission of high-frequency magnetic fields (frequencies >> 1 kHz). However, applications at lower frequencies are not yet known. Lower frequencies refer to frequencies below 65 Hz.

[0067] An additional advantage of soft magnetic powder composite materials is that they have excellent ability for three-dimensional magnetic flux transfer, high electrical resistance and high permeability, and therefore have virtually no eddy current losses. In particular, the ability for three-dimensional magnetic flux transfer without high eddy current losses during the process ensures that soft magnetic powder composite materials are preferably used for pole pieces and / or connecting legs.

[0068] Because soft magnetic powder composite materials have relatively high hysteresis losses, in some embodiments, soft magnetic powder composite materials are used to manufacture pole pieces and / or connecting legs. As a result, a balance is found between the reduction of eddy current losses, particularly at locations where eddy current losses are high, and the undesirable effects of the powder composite material on the magnetic circuit.

[0069] Attaching the pole piece to the connecting leg and attaching the connecting leg to the radial portion of the segment can be performed by a plurality of possible joining methods. These include, in particular, force-interlocking joining, such as clamping or crimping; shape-interlocking joining, such as screw fastening or fitting; or cohesive joining, such as bonding or welding. It is also possible to form a connection through tongue-and-groove connections and / or bun connections, such as pin, hook, or dovetail connections. In a preferred embodiment, the cohesive type joining is implemented by adhesive bonding. This has the advantage of not causing excessive stress on the material compared to clamping or screw fastening. Furthermore, force-interlocking and shape-interlocking type joining has the advantage of having low sensitivity to defects caused, for example, by aging or defects during adhesive bonding.

[0070] According to a preferred embodiment, the end face has a shape transition, preferably a rounded portion or a step, at the edge forming the transition to the surface of the pole piece. In other words, the edge located at the axial top of the end face of the pole piece and likewise forming the radially inner edge of the surface of the pole piece has a shape transition. On the one hand, the shape transition can be understood to mean that the transition from the end face to the surface of the pole piece has a predetermined radius at said edge. It can also be said that said edge is broken. If the pole piece is designed in a stacked manner from axially stacked pole elements, the pole piece may likewise have a shape transition. In this case, in addition to the shape transition mentioned above, the shape transition may also be understood to mean that at least one pole element located at the axial top of the pole piece has a smaller radial extension than other elements. In other words, at least one pole element is retracted from the rotor when viewed radially from the other pole element, that is, is at a greater distance from the rotor than other pole elements.

[0071] According to a preferred embodiment, the end face has at least one slot extending axially. That is, in other words, at least one slot can extend axially from the end face for any length.

[0072] Furthermore, it is desirable that multiple slots be arranged parallel or nearly parallel to each other on the end face.

[0073] Arranging multiple slots parallel to each other is advantageous because they are also arranged parallel or at least nearly parallel to the path of the magnetic field, and consequently do not block the magnetic field.

[0074] Furthermore, it is desirable that at least one slot extends from the surface of the pole piece to the bottom surface of the pole piece. Thus, this extension will be the maximum possible extension of the slot within the end face in the axial direction.

[0075] In the case of a possible design in which the end face has two or more slots, it is possible for one slot to extend axially from the bottom surface of the pole piece and for a second slot to extend axially from the surface of the pole piece in the opposite direction to the first slot. In this case, it is possible for each of the two slots to have an axial extension of less than 50% of the axial extension of the end face. That is to say, the end face has two slots that do not come into contact with each other at the center of the end face, so that at least one pole element of the pole piece is present at that location and said pole element is not captured by the slot.

[0076] Electrical insulation is formed by introducing at least one slot into the end face of the pole piece. That is, the at least one slot ensures that the eddy current path within the pole element is interrupted and thus blocked. Accordingly, eddy currents formed by the magnetic field generated from the pole element in the axial direction can be prevented or reduced. This results in only a small amount of eddy current remaining within the pole piece, and the eddy current loss throughout the pole piece is significantly reduced overall.

[0077] The formation of slots can be performed by various methods. These include, in particular, mechanical methods such as milling, punching, or cutting, the latter also include laser and / or waterjet cutting and / or wire discharge.

[0078] According to a preferred embodiment, the connecting leg and the pole piece are integrally formed as teeth.

[0079] Attaching the teeth to the back iron or segment can also be done by the possibilities described above.

[0080] According to a preferred embodiment, the teeth can be manufactured from a solid material. The previously described SMC is suitable for this purpose.

[0081] According to a preferred embodiment, the teeth are manufactured by stacking tooth elements, and the tooth elements are stacked in the circumferential direction of the stator. Here, it is particularly advantageous that the stacking of the tooth elements is performed in the circumferential direction so that the magnetic field can be transmitted in both the radial and axial directions, while simultaneously maintaining the effect of reducing eddy current losses in the case of magnetic fields in the axial and radial directions.

[0082] It is preferable that the teeth be manufactured from soft magnetic materials.

[0083] According to a particularly preferred embodiment, the stator of the magnetic levitation device is configured to generate torque such that the rotor can be magnetically driven in a non-contact manner for rotation around the axis.

[0084] Here, the stator is composed of a bearing and a drive stator, which is the stator of the electric drive unit and simultaneously the stator of the magnetic levitation device. By means of the electric windings of the stator, a magnetic rotation field can be generated that applies a torque to the rotor on one hand to cause the rotor to rotate around a desired axis of rotation, and on the other hand applies an arbitrarily adjustable lateral force to the rotor to enable the radial position of the rotor to be actively controlled or adjusted.

[0085] Particularly with respect to embodiments in which a magnetic levitation device is configured to generate torque, a design with a wider end face is advantageous because it improves magnetic functionality. For example, increased torque can be generated, or passive stiffness or active bearing force can be enhanced.

[0086] According to a preferred embodiment, the magnetic levitation device is configured as an electromagnetic rotary drive unit or a mixing device or a centrifuge or a cross-flow fan or a rotary filter or a viscometer.

[0087] That is, the magnetic levitation device according to the present invention can be configured or used for various fluid transfer units as previously mentioned. In such cases, the fluid transfer unit includes a rotor, and the rotor provides energy to the fluid by rotation and thus moves the fluid.

[0088] Furthermore, an electromagnetic rotary drive unit, also referred to as a step motor, is proposed by the present invention, said electromagnetic rotary drive unit comprises a magnetic levitation device according to the present invention and a rotor having a disc-shaped or ring-shaped magnetic active core, said rotor may be inserted into a cup-shaped recess, and said rotor is configured as the rotor of the electromagnetic rotary drive unit.

[0089] Such electromagnetic rotary drives are also known by the term "bearingless motor." In this context, the term "bearingless motor" refers to an electromagnetic rotary drive in which the rotor is completely magnetically levitated relative to the stator and no separate magnetic bearings are provided.

[0090] Furthermore, a pump unit for a magnetic levitation device according to the present invention is proposed by the present invention, wherein the pump unit comprises a rotor and the pump unit has a pump housing having an inlet and an outlet for a fluid to be transported. The rotor is disposed within the pump housing and the rotor has a plurality of vanes for transporting the fluid. The pump housing partitions a pump chamber and the pump housing has a cover portion and a base portion. The base portion has a cylindrical or conical cup for receiving the rotor, and the cup may be inserted into a cup-shaped recess of the stator.

[0091] Further advantageous measures and embodiments of the present invention are provided in the dependent claims. Brief explanation of the drawing

[0092] Hereinafter, the present invention is described in more detail based on exemplary embodiments and drawings. The drawings represent the following: FIG. 1 is a perspective view of a conventional magnetic levitation device according to a temple structure. FIG. 2 is a perspective view of a first exemplary embodiment of a magnetic levitation device according to the present invention. FIG. 3 is a schematic cross-sectional view of an embodiment of a magnetic levitation device according to the present invention having a stator housing. FIG. 4 is a perspective view of a segment with a stator pole disposed thereon in an exemplary embodiment of FIG. 2, FIG. 5 is a perspective view of a segment having the stator pole of FIG. 4, having a first winding shape, disposed thereon. FIG. 6 is a plan view of a segment having a stator pole having the first winding shape of FIG. 5 disposed thereon. FIG. 7 is a plan view of a segment having a stator pole having a second winding shape disposed thereon. FIG. 8 is a perspective view of a second embodiment of a segment with a stator pole disposed thereon. FIG. 9 is a perspective view of a third embodiment of a segment with a stator pole disposed thereon. FIG. 10 is a perspective view of a fourth embodiment of a segment having a first winding shape with a stator pole disposed thereon. FIG. 11 is a perspective view of a fifth embodiment of a segment having a first winding shape with a stator pole disposed thereon. FIG. 12 is a perspective view of a sixth embodiment of a segment having a first winding shape with a stator pole disposed thereon. FIG. 13 is a schematic cross-sectional view of a second exemplary embodiment of a magnetic levitation device according to the present invention. FIG. 14 is a plan view of a third exemplary embodiment of a magnetic levitation device according to the present invention. FIG. 15 is a plan view of a fourth exemplary embodiment of a magnetic levitation device according to the present invention. FIG. 16 is a schematic diagram of the wiring of a magnetic levitation device according to the present invention. FIG. 17 is a cross-sectional view of a magnetic levitation device according to the present invention with a pump unit inserted therein, and FIG. 18 is a cross-sectional perspective view of a magnetic levitation device according to the present invention with a mixing unit inserted therein. Specific details for implementing the invention

[0093] As already explained above, FIG. 1 shows a perspective view of a conventional magnetic levitation device (1′) according to a temple structure.

[0094] FIG. 2 illustrates a perspective view of an exemplary embodiment of a magnetic levitation device according to the present invention, collectively referred to as reference numeral 1. The magnetic levitation device (1) is designed for non-contact magnetic levitation of a rotor (3) comprising a disc-shaped or ring-shaped magnetic active core (31). The magnetic levitation device (1) comprises a stator (2). The stator (2) typically comprises a stator housing (21) (Fig. 3), but this is not illustrated in FIG. 2 for clarity. Therefore, FIG. 3 illustrates an embodiment of the stator housing (21) in a schematic cross-sectional view. FIG. 3 is intended only to serve as an example to show how the encapsulation of the internal space of the stator (2) required for the operation of the magnetic levitation device (1) looks. For this reason, other components of the stator (2) are illustrated only schematically and should be understood as being for illustrative purposes only.

[0095] For example, in areas where chemically corrosive substances are used, it is important that the interior of the stator (2) be securely sealed and thus protected from such substances during the operation of the magnetic levitation device (1). Nevertheless, in order to allow the rotor (3) to be used, the stator housing (21) has a cup-shaped recess (211) in which the rotor (3) can be inserted at one axial end.

[0096] The portion of the stator housing (21) located near the concentrated winding (61) at the axial upper portion (AE1) of the stator (2) and the portion of the stator housing (21) facing the cup-shaped recess (211) are preferably made of a low-loss material, and particularly preferably, are made of a material that is electrically non-conductive or only weakly conductive, such as plastic, for example. Other portions of the stator housing (21) are preferably made of a material having high thermal conductivity, such as aluminum, for example. The stator housing (21) is preferably hermetically sealed, or, depending on the design of the housing (21), is already hermetically sealed during manufacturing so that harmful substances inside the magnetic levitation device (1) cannot come into contact with the stator (2). An exemplary embodiment in which the housing (21) has a coating, for example, one or more polymer coatings that are chemically durable or corrosion-resistant, is also possible.

[0097] A cooling device may be provided in the stator housing (21), and the cooling device cools the magnetic levitation device (1), particularly the stator (2), and thus protects it from overheating.

[0098] The stator housing (21) can be filled with a casting compound that, on one hand, fixes the stator (2) in a predetermined position and, on the other hand, contributes to the thermal control of the stator (2) or the magnetic levitation device (1).

[0099] The electronic device for operating the magnetic levitation device (1) may be placed inside, that is, inside the stator housing (21), or may be placed entirely or partially outside, for example, in a separate electronic component. The electronic component may be placed away from the magnetic levitation device (1) and connected via one or more cables, for example, or may be attached to the outer wall of the housing (21). In particular, the electronic device includes all components for the levitation and driving of the rotor, as well as components for sensor technology, for example.

[0100] The rotor (3) is configured to rotate around a desired axis of rotation. This desired axis of rotation forms an axial direction (A). The central axis of the stator (2) extending in the axial direction (A) generally coincides with the desired axis of rotation. In this case, the desired axis of rotation represents the axis of rotation around which the rotor (3) rotates in an operating state when the rotor (3) is centered and not tilted with respect to the stator (2), as shown in FIG. 2.

[0101] The stator further has a back iron (28), said back iron (28) comprises a plurality of segments (281)—here, 12 segments (281)—each segment (281) having a radial portion (282), a circumferential portion (283), a back iron bottom surface (284), and a back iron surface (285). However, an exemplary embodiment in which the back iron (28) does not have segments (281) is also possible.

[0102] In these exemplary embodiments, the number of segments (281) is merely illustrative. The back iron (28) may contain more or fewer segments (281) than 12. Each radial portion (282) extends from the circumferential portion (283) in a radial direction (R) perpendicular to the axial direction (A).

[0103] On each radial portion (282), at least one concentrated winding (61) is disposed surrounding the individual radial portion (282). The at least one concentrated winding (61) has a radial first end (611) and a radial second end (612), the radial first end (611) faces the circumferential portion (283), and the radial second end (612) faces the cup-shaped recess (211). In other embodiments, two or more concentrated windings (61) may be disposed on the radial portion (282). For example, there exists an exemplary embodiment in which exactly two concentrated windings are provided on each radial portion (282), each of which surrounds the corresponding radial portion (282), and the two windings (61) disposed on the same radial portion (282) are disposed adjacent to each other with respect to the axial direction (R).

[0104] In this exemplary embodiment, the concentrated winding (61) is in a conical configuration. For better understanding, a plan view of a segment (281) having a stator pole (25) having a first winding shape placed thereon is shown in FIG. 6. In other words, the concentrated winding (61) in a conical configuration is understood to mean a winding (61) in which at least one concentrated winding (61) has a first outer diameter (WA1) at a radial first end (611) and a second outer diameter (WA2) at a radial second end (612), wherein the first outer diameter (WA1) is larger than the second outer diameter (WA2).

[0105] The concentrated winding (61) serves to generate a magnetic field, thereby allowing the rotor (3) to be magnetically levitated in a contactless manner within the cup-shaped recess (211, see FIG. 3).

[0106] The back iron surface (285) faces the first axial end (AE1) of the stator (2), and the back iron bottom surface (284) faces the second axial end (AE2) of the stator (2).

[0107] The stator (2) has a plurality of stator poles (25)—here, 12 stator poles (25)—each having a connecting leg (26) and a pole piece (27). The number of stator poles (25) should be understood as merely exemplary, and there may be more or fewer stator poles (25). In this exemplary embodiment, the number of stator poles (25) is equal to the number of segments (281), because one stator pole (25) is placed on each segment (281). However, an exemplary embodiment in which two or more stator poles (25) are placed on a single segment (281) is also possible. In the case of the number of stator poles (25) mentioned in this exemplary embodiment, it is therefore possible for only six segments (281) to exist, with two stator poles (25) placed on each segment (281).

[0108] For better understanding, a perspective view of a segment (281) with a stator pole (25) placed thereon is shown in FIG. 4, and additionally, a concentrated winding (61) of the magnetic levitation device (1) of FIG. 2 surrounds a radial portion (282) of FIG. 5.

[0109] Each connecting leg (26) extends from a first end (261) to a second end (262), where the first end (261) contacts a back iron (28) or, in each case, a segment (281). The connecting leg (26) has a first contact surface (263) corresponding to the surface that contacts the segment (281). Furthermore, each pole piece (27) has a contact surface (271) that contacts the second end (262) of the connecting leg (26). The pole piece (27) extends radially (R) from the contact surface (271) to an end face (272). The end face (272) of all pole pieces (27) is positioned around a cup-shaped recess (211).

[0110] Intermediate spaces exist between adjacent pole pieces (27), and at least one sensor is introduced in at least one intermediate space. However, multiple intermediate spaces may have at least one additional sensor, so in some exemplary embodiments, at least one sensor is placed in each intermediate space. For example, at least one sensor may be provided to measure rotor properties, such as the position of the rotor, and / or to measure stator properties, such as temperature. In particular, the following types of sensors may be used for this purpose: Hall sensors, eddy current sensors, optical sensors, capacitive sensors, and temperature sensors. Additionally, combinations of the aforementioned sensors may also be provided. In all illustrated exemplary embodiments, sensors are not illustrated for clarity.

[0111] In the exemplary embodiment of FIG. 2, the end face (272) of the pole piece (27) is each configured as a curved surface. The curved portion of the end face (272) is configured coaxially with respect to the cup-shaped recess (211). In other words, the end face (272) of the pole piece (27) is part of the cylindrical surface, and the central axis of this cylinder coincides with the central axis of the cup-shaped recess (211), and its radius is larger than the radius of the cup-shaped recess (211), thus preventing the end face (272) from protruding into the cup-shaped recess (211). However, an exemplary embodiment in which the end face (272) does not have a curved portion is also possible.

[0112] Furthermore, the end face (272) of FIG. 2 is configured to be wider than the maximum circumferential extension of the contact surface (271) with respect to the circumferential direction. This means that one of the two edges (2721, 2722) of the circumferentially extended end face (272) is longer than one of the edges (2711, 2712) of the circumferentially extended contact surface (271). In the case where the end face (272) is configured as a curved surface, the length of one of the arcs of the segment of the cylindrical surface in the radial plane is longer than the length of one of the edges (2711, 2712) of the circumferentially extended contact surface (271).

[0113] This circumferential extension of the end face (272) is advantageous because it improves magnetic function. For example, passive rigidity and active levitation force can be improved.

[0114] However, exemplary embodiments in which the end face (272) is the same width as or narrower than the maximum extension of the circumferential contact surface (271) are also possible.

[0115] The segments (281) of the back iron are arranged adjacent to each other on a circular line, so that a pole piece (27) or its end face (272) connected to the segments (281) through a connecting leg (26) surrounds the magnetic active core (31) of the rotor (3) when the rotor (3) is inserted into the cup-shaped recess (211).

[0116] Each connecting leg (26) extends radially inward from the first end (261) at an angle with respect to the axial direction (A) to the second end (262), so that the back iron surface (285) and the pole piece surface (273) of the pole piece (27) are positioned with an offset (V) with respect to the axial direction (A).

[0117] Extending radially inward of the connecting leg (26) means that the second end (262) of the connecting leg is at a shorter distance from the cup-shaped recess (211) than the first end (261). Extending obliquely with respect to the axial direction (A) means that the axis (AV) of the connecting leg (26) forms an angle (α) with respect to the axial direction (A) that is greater than 0° and less than 90°. The angle (α) is preferably 20° to 60°, and the angle (α) is particularly preferably 30° to 55°. The axis (AV) of the connecting leg (26), which forms an angle (α) with the axial direction (A), preferably extends from the first center point of the first contact surface (263) of the connecting leg (26) to the second center point of the second contact surface (265) of the connecting leg (26) (Fig. 4), and the second contact surface (265) is positioned on the contact surface (271) of the pole piece (27).

[0118] Now, by comparing the prior art of FIG. 1 with the exemplary embodiment of the magnetic levitation device (1) of FIG. 2, it can be directly observed that the magnetic levitation device (1) is a significantly more compact design, particularly with respect to the axial direction (A). An additional advantage is that in the magnetic levitation device (1) according to the present invention, significantly more stator poles (25) can be arranged around the cup-shaped recess (211). This ensures that the corresponding surface of the rotor (3) facing the end face (272) of the pole piece (27) when viewed in the circumferential direction is more widely covered by the stator poles (25). Thus, better magnetic flux transmission of the magnetic field is achieved.

[0119] Furthermore, it is also advantageous that a flat surface of the stator (2) is achieved at the axial upper portion (AE1) of the stator (2) as a result of the pole piece (27) being offset with respect to the segment (281). In the absence of the offset (V), at least one concentrated winding (61) placed on the radial portion (282) of each segment (281) has an axial extension (WD) (Fig. 3), so the surface (613) of the concentrated winding (61) is placed on the back iron surface (285) in the axial direction, and thus no flat surface exists. That is, thus, the stator housing (21) surrounding the stator (2) has a flat surface at the axial upper portion (AE1) of the stator (2). In other words, the axial upper surface (22) of the stator housing (21) is located within a single radial plane. This is advantageous to the magnetic levitation device (1) because better interaction between the stator (2) and the rotor (3) is consequently achieved. When the magnetic levitation device (1) is configured for an application such as a mixing device, for example, the offset (V) additionally has the advantage that the rotor (3) can be positioned closer to the intended location of the mixing device. As a result, the magnetic levitation device (1) can be designed to be more compact.

[0120] Furthermore, it is also advantageous that the concentrated winding (61) can be positioned closer to the rotor (3), so that losses in the magnetic levitation device (1) are reduced.

[0121] The rotor (3) or magnetic active core (31) has a radius center plane (RM1) (Fig. 3), which coincides with the radius center plane (RM2) of the pole piece (27) in the stationary position. Then, it is ensured that the levitation of the rotor (3) is well and reliably guaranteed.

[0122] Segment (281) and pole piece (27) each have an axial thickness (DS, DP) in the axial direction (A) (Fig. 4), which is the same size in this exemplary embodiment, and the axial distance (A1) between the back iron bottom face (284) and the pole piece surface (273) is greater than the axial thickness (DS or DP). However, other embodiments are possible in which the axial thickness (DS, DP) is not the same, i.e., larger or smaller, and thus the distance relationship is unnecessary.

[0123] The offset (V) in the axial direction (A) must be greater than 0% and less than 100% of the axial thickness (DP) of the pole piece (27). The offset (V) is preferably 5% to 75% of the axial thickness (DP), and particularly preferably 15% to 45%.

[0124] This means that the pole piece (27) is displaced upward in the axial direction (A) toward the axial upper portion (AE1) relative to the segment (281). This also results in, on one hand, the back iron bottom surface (284) and the pole piece bottom surface (274) not being located within the same radial plane but having an offset (V) relative to each other, and on the other hand, the pole piece surface (273) being positioned closer to the axial upper portion (AE1) of the stator (2) than the back iron surface (285) in the axial direction (A).

[0125] Preferably, the pole piece surface (273) is positioned closer to the axial upper portion (AE1) of the stator (2) than the surface of the winding (61) in the axial direction (A), and the surface of the winding (61) is the surface positioned closest to the axial upper portion (AE1). This applies equally even when the winding (61) is surrounded by an insulator, etc.

[0126] In this exemplary embodiment of the magnetic levitation device (1), the components (segment (281), connecting leg (26) and pole piece (27)) are all designed in a stacked manner from elements (264, 275, 286).

[0127] Here, the segment (281) is manufactured by lamination from a back iron element (286), and the back iron element (286) is laminated in the axial direction (A). The connecting leg (26) is manufactured by lamination from an element (264), and the element (264) is laminated in the circumferential direction of the stator (2). The pole piece (27) is manufactured by lamination from a pole element (275), and the pole element (275) is laminated in the axial direction (A).

[0128] The number of elements (264, 275, 286) in all exemplary embodiments and drawings should be understood as merely illustrative. The number may be more or less than that depicted.

[0129] Changing the orientation of the stacked design between individual components (281, 26, 27) ensures that the eddy current losses of the entire magnetic levitation device are reduced.

[0130] The elements (264) of the connecting leg (26) stacked in the circumferential direction have the advantage of lower loss in this case and reduced magnetic resistance compared to when the elements (264) of the connecting leg (26) are stacked in the axial direction (A). This is because, in the case of the elements (264) stacked in the circumferential direction, the magnetic field does not need to pass through the axial (A) stacking plane and the insulation between the stacking planes in each case. That is, conversely, if the connecting leg (26) is stacked in the axial direction (A), the magnetic field must pass through the stacking plane, and as a result, loss will occur and increased magnetic resistance will be experienced.

[0131] The orientation of the stacking of individual elements (264, 275, 286) is based on these exemplary embodiments. For all components (281, 26, 27), other orientations of the stacking of their individual elements (264, 275, 286) are also possible. However, preferably, a change in orientation exists in the transition from one component (281, 26, 27) to the component (281, 26, 27) placed thereon.

[0132] One advantage of the stacked design is that it ensures a reduction in eddy current losses within the individual components (281, 26, 27).

[0133] Most eddy current losses occur in the pole piece (27), because the distance between adjacent pole pieces (27) is particularly small, especially at the end facing the cup-shaped recess (211). The magnetic field is initially generated radially (A) from the pole piece (27). Eddy currents are effectively reduced by stacking elements of individual components (281, 26, 27). The magnetic field of two adjacent pole pieces (27) in the circumferential direction of the stator (2) is also generated circumferentially from it. Therefore, it is necessary to select a stack of individual elements (264, 275, 286) that effectively prevents the generation of magnetic fields and associated eddy currents in the circumferential direction as well. This is ideally possible in the case of the pole piece (27) by stacking the pole elements (275) axially (A). Likewise, as an alternative, the pole piece (27) may be manufactured from a soft magnetic composite material (soft magnetic composite, abbreviated as "SMC"). This ensures a similar effect. Overall, this embodiment results in a significant reduction in eddy current losses.

[0134] As a result, as can be seen in FIG. 2, the pole pieces (27) can be positioned significantly closer to each other in the circumferential direction of the stator (2), and thus, compared to the temple motor of FIG. 1, the possibility arises to position several (here, 12) stator poles (25).

[0135] In a preferred embodiment, the pole piece (27) is manufactured from a soft magnetic material. In this case, the pole piece (27) and / or the segment (281) and / or the connecting leg (26) are preferably manufactured from electrical steel. The definition of electrical steel has already been described in the preceding section. There is also a possibility of using mu-metal for the manufacture of the elements (264, 275, 286).

[0136] Additional suitable soft magnetic materials for the stator pole (25) and back iron (28) are, for example, ferromagnetic or ferrimagnetic materials, namely iron, nickel-iron, cobalt-iron, silicon-iron, or mu-metal.

[0137] In other exemplary embodiments, the pole piece (27) and / or connecting leg (26) and / or back iron (28) or segment (281) may be manufactured from powder composite material, in particular soft magnetic powder composite material (SMC). The definition and advantages of such material have already been described in the preceding section.

[0138] Attaching the pole piece (27) to the connecting leg (26) and attaching the connecting leg (26) to the radial portion (282) of the segment (281) can be done by the possible joining method already described in the preceding section.

[0139] According to a particularly preferred embodiment, the stator (2) is designed to apply torque to the rotor (3) or the magnetic active core (31) of the rotor (3) in addition to the non-contact magnetic levitation of the rotor (3), which drives the rotor (3) for rotation around a desired axis of rotation. That is, in this preferred design, the rotor (3) can be driven to rotate around an axial direction (A).

[0140] The end face (272) extending circumferentially as previously mentioned has the advantage that magnetic functionality is improved in this way. For example, passive rigidity and active levitation force can be improved. In relation to an embodiment in which the magnetic levitation device (1) is configured to generate torque, there is an additional advantage that increased torque can be generated.

[0141] In this embodiment, the concentrated winding (61) thus generates an electromagnetic rotational field, thereby allowing the rotor (3) to be magnetically levitated non-contactually with respect to the stator (2), as well as to be driven to rotate non-contactually around the axial direction (A).

[0142] The rotor (3) includes a magnetic active core (31), and this core is designed in a ring shape or a disk shape. According to the illustration in FIG. 3, the magnetic active core (31) is configured in a ring shape and forms a magnetic center plane. A plurality of individual magnets (311) are placed on the magnetic active core. This is a so-called four-pole rotor (3). It is obvious that a rotor (3) having four and a different number of pole pairs, for example, a single-pole rotor (3), may be used in other exemplary embodiments.

[0143] In relation to an exemplary embodiment having a four-pole pair rotor (3) illustrated in the drawing, it is advantageous for the pole piece (27) to be designed in an axially stacked stacked manner. When a change between individual magnets (311) of the rotor (3) occurs in a specific pole piece (27) during the operation of the magnetic levitation device (1), i.e., as shown in detail AS in FIG. 2, the magnetic field is introduced into the pole piece (27) at a first point of the pole piece (27) and exits from the same pole piece (27) again at a second point displaced in the circumferential direction. This magnetic flux transfer is possible with low loss only in the case of axially stacked and stacked pole pieces (27). Here, the circumferentially stacked element (275) would oppose the magnetic field path during the pole change and cause high loss.

[0144] When a soft magnetic composite material (SMC) is used as a material for a pole piece (27) or a tooth (29) (Fig. 8), the same advantages as described above occur. Likewise, SMC is also very suitable for use with a four-pole pair rotor (3).

[0145] Alternatively, the magnetic active core (31) may be configured as a disk. As a rule, in the case of a disk-shaped or ring-shaped magnetic active core (31), the magnetic center plane is the geometric center plane of the magnetic active core (31) of the rotor (3) perpendicular to the axial direction (A). In the operating state, the magnetic active core (31) is levitized in a radiating plane perpendicular to the axial direction (A).

[0146] For the sake of sufficient understanding of the invention, only the magnetic active core (31) of the rotor (3) is shown in FIG. 2. Of course, it is obvious that the rotor (3) may further include additional components, such as a casing or encapsulation, which is preferably made of, for example, plastic, or metal or metal alloy or ceramic or ceramic material. Furthermore, the rotor (3) may further include blades or other components for mixing, stirring, or pumping fluids.

[0147] When the rotor (3) is inserted into the cup-shaped recess (211), the rotor (3) and, in particular, the magnetic active core (31) of the rotor (3) are surrounded by end faces (272) positioned radially outward from the pole piece (27) of the stator pole (25) of the stator (2).

[0148] When the magnetic active core (31) of the rotor (3) is in a desired position during operation, the magnetic active core (31) is centered between the end faces (272) of the pole piece (27).

[0149] In order to generate the electromagnetic field necessary for magnetic levitation of the rotor (3) and optionally to generate torque for the rotor (3), the radial portion (282) of the segment (281) has a winding composed of a concentrated winding (61). However, an embodiment in which the concentrated winding (61) is placed in both the radial portion (282) and part of the connecting leg (26) is also possible (Fig. 9).

[0150] By means of these concentrated windings (61), an arbitrarily adjustable lateral force can be applied to the rotor (3) in the radial direction in the operating state, thereby creating an electromagnetic rotation field that allows the radial position of the rotor (3), i.e., the position in the radial plane perpendicular to the axial direction (A), to be actively controlled or adjusted. Optionally, torque is additionally generated on the rotor (3) by this electromagnetic rotation field. The tilting of the rotor (3) can be passively stabilized by a ring-shaped or disc-shaped embodiment of the rotor (3). The diameter of the magnetic active core (31) of the rotor (3) is preferably at least twice the core height of the magnetic active core (31), said core height defines the axial (A) extension of the magnetic active core.

[0151] The "magnetic active core (31)" of the rotor (3) refers to a region of the rotor (3) that magnetically interacts with the stator (2) to generate magnetic levitation force and optionally to generate torque.

[0152] As previously mentioned, in this exemplary embodiment, the magnetic active core (31) is ring-shaped and has several individual magnets (311) placed thereon. However, an exemplary embodiment in which the magnetic active core (31) does not have individual magnets (311) placed thereon is also possible. Now, the magnetic active core (31) can be composed entirely of a permanent magnet material, and as a result, the magnetic active core (31) becomes a permanent magnet. The magnetic active core (31) is magnetized, for example, in the radial direction.

[0153] Permanent magnets generally refer to hard magnets, that is, ferromagnetic or ferrimagnetic materials having high coercivity. Coercivity is the magnetic field strength required to demagnetize a material. In the context of this application, permanent magnets are understood to mean a material or material having a coercivity, more precisely, a coercivity of magnetic polarization greater than 10,000 A / m.

[0154] Preferably, the stator (2) and the rotor (3) have a predetermined pole number combination. The number of poles of the stator (2) corresponds to the number of stator poles (25), while the number of poles of the rotor (3) corresponds to the number of magnetic poles, in particular the number of permanent magnets. The preferred combination of stator poles and magnetic poles is given by the following number of pairs:

[0155] Stator pole stimulation 5 2 6 2 8 2 9 6 12 8 12 14 24 20 36 30

[0156] An embodiment in which the magnetic active core (31) is designed without a permanent magnet, that is, in a form without a permanent magnet, is also possible. Then, the rotor (3) is designed, for example, as a reluctance rotor. Now, the magnetic active core (31) of the rotor (3) is composed, for example, of a soft magnetic material. The soft magnetic material for the magnetic active core (31) is, for example, a ferromagnetic or ferrimagnetic material, namely, particularly iron, nickel-iron, cobalt-iron, silicon-iron, and mu-metal. Furthermore, an embodiment in which the magnetic active core (31) of the rotor (3) includes both a ferromagnetic material and a permanent magnetic material is also possible. For example, a permanent magnet may be placed or inserted within the ferromagnetic body. Such a design is advantageous when it is intended to reduce costs by reducing the permanent magnet material, for example in the case of a large rotor. An embodiment in which the rotor is constructed according to the principle of a cage rotor is also possible.

[0157] In contrast, the stator (2) has no permanent magnets. By this expression that the stator (2) is configured "without permanent magnets," it is intended to be understood in the context of this application that the stator (2) does not include any permanent magnets that substantially contribute to the driving magnetic field for driving the rotation of the rotor (3) or for generating magnetic levitation for the rotor (3). Therefore, the magnetic flux generated by the stator (2) for driving and levitating the rotor (3) does not include magnetic flux excited by permanent magnets.

[0158] Of course, it is possible to include another magnet or permanent magnet within the sensor that serves a purpose other than generating magnetic flux for driving and lifting the rotor (3) and / or stator (2), for example, to detect the angular position of the rotor, or otherwise perform a purpose unrelated to generating magnetic flux for driving and lifting the rotor (3).

[0159] Therefore, the expression “without permanent magnets” relates only to the generation of magnetic flux by the stator (2) for driving and levitating the rotor (3). In other words, the stator (2) does not have permanent magnets that contribute to the magnetic flux driving and magnetically levitating the rotor (3).

[0160] However, nevertheless, it is still possible for the magnetic flux for driving and levitating the rotor (3) to include permanent magnetic flux, but in this case, it is generated only by the rotor (3) itself. This would be the case where the rotor (3) itself includes a permanent magnet.

[0161] During the operation of the magnetic levitation device (1), the magnetic active core (31) of the rotor (3) interacts with the stator (2) in such a way that the rotor (3) can be magnetically levitized non-contactually with respect to the stator (2), and preferably additionally magnetically rotated non-contactually around the axial direction (A). In this case, it is particularly advantageous for the same winding (61) that generates the magnetic levitation of the rotor (3) to also perform the role of generating torque on the rotor (3). Preferably, the three degrees of freedom of the rotor (3), namely the position and rotation in the radiating plane, can now be actively controlled. With respect to that axial displacement in the axial direction (A) away from the radiating plane, the magnetic active core (31) of the rotor (3) is passively magnetically stabilized by the reluctance force, i.e., cannot be actuated. Also, regarding the remaining two degrees of freedom, namely tilting with respect to the radiating plane perpendicular to the desired axis of rotation, the magnetic active core (31) of the rotor (3) is likewise passively magnetically stabilized. Therefore, the rotor (3) is passively magnetically levitated or passively magnetically stabilized in the axial direction (A) and against tilting (total of 3 degrees of freedom) by the interaction between the magnetic active core (31) and the stator pole (25), and is actively magnetically levitated in the radiating plane (2 degrees of freedom).

[0162] As is generally customary, in the context of this application, active magnetic levitation refers to such levitation that can be actively controlled or regulated, for example, through an electromagnetic field generated by a concentrated winding (61). Passive magnetic levitation or passive magnetic stabilization refers to that which cannot be driven or regulated. Passive magnetic levitation or stabilization is based on a reluctance force to return the rotor (3) to its desired position, for example, in the event of displacement from its desired position, i.e., in the event of displacement or deflection in the axial direction (A) or tilting.

[0163] In contrast to conventional magnetic levitation, in the magnetic levitation device (1), the generation of magnetic levitation and optionally torque acting on the rotor is realized through an electromagnetic rotating field. For the combined generation of magnetic levitation force and torque to rotate the rotor (3) around the axial direction (A), on the one hand, it is possible to place exactly one concentrated winding (61) on each radial portion (282) as shown in FIG. 2.

[0164] On the other hand, an embodiment is also possible in which two different winding systems are provided for the combined generation of magnetic levitation force and torque for the rotor (3). For this purpose, exactly two concentrated windings arranged adjacent to each other in the radial direction (A) are now placed in each case, for example, on each radial section (282). One of these two windings belongs to the first winding system of the two-winding system, and the other belongs to the second winding system of the two-winding system.

[0165] In the embodiment illustrated in FIG. 2, where there is exactly one concentrated winding (61) on each radial section (282), values ​​determined by the control unit in each case for the current required for levitation and the current required for torque generation are computationally added or superimposed, i.e., processed, for example, with the help of software. The total current derived therefrom is applied to the individual concentrated winding (61).

[0166] When the stator (2) of the magnetic levitation device (1) according to the present invention is configured to generate torque, the magnetic levitation device (1) is suitable for an electromagnetic rotary drive unit. Likewise, the magnetic levitation device (1) according to the present invention may also be suitable for other devices, such as, for example, a centrifugal pump, a mixing device for mixing fluid materials, for example, a stirring device for mixing fluid in a tank, a centrifuge, a viscosity sensor, a rotary filter, a fan, or, for example, a device for transporting and rotating a wafer in semiconductor manufacturing.

[0167] FIG. 7 illustrates a plan view of a segment (281) having a stator pole (25) having a second winding shape (61a) placed thereon.

[0168] Here, the coil has a straight rectangular shape, that is, the outer and inner diameters of the concentrated winding (61a) are the same size at the radial first end (611) and the radial second end (612). Here, it is advantageous that this winding shape is easier to manufacture. However, this winding shape has the disadvantage that the circumferential extension of the radial portion (282) is the same size everywhere within the radial portion (282), and therefore the material area is smaller compared to the radial portion (282) within the conical first winding shape (Fig. 6). As a result, more iron loss occurs in the second winding shape than in the first winding shape.

[0169] An exemplary embodiment of a magnetic levitation device (1) is also possible in which the back iron (28) includes both the segment (281) surrounded by the first winding-shaped concentrated winding (61) of the exemplary embodiments of FIGS. 2, 5 and 6 and the segment (281) surrounded by the second winding-shaped concentrated winding (61a) of FIG. 7.

[0170] Furthermore, an exemplary embodiment of a magnetic levitation device (1) is also possible in which the second winding shape (61a) of FIG. 7 and the back iron (28) are formed integrally without including a segment (281). Due to the design of the second winding shape (61a), it is possible for the second winding shape to be directly attached to the back iron (28) having a plurality of radial portions (282). As a result of the geometric design of the second winding shape (61a), the second winding shape can be easily pushed onto the radial portions (282) without the adjacent windings (61a) interfering with each other. Subsequently, a pole piece (27) can be attached to each radial portion (282).

[0171] FIG. 8 illustrates a perspective view of a second embodiment of a segment (281) on which a stator pole (25) is disposed thereon. In this embodiment, the connecting leg (26) and the pole piece (27) are integrally formed as a tooth (29).

[0172] Attaching the gear (29) to the segment (281) can be done by means of the possibilities already described above.

[0173] The gear (29) is manufactured by stacking gear elements (291), and the gear elements (291) are stacked in the circumferential direction of the stator (2). Here, since the stacking of the gear elements (291) is in the circumferential direction, it is important that the effect already described acts between the radial portion (282) of the segment (281) and the gear (29) placed thereon to reduce eddy current loss when the orientation of the elements (286, 291) is changed. The selection of the material for the gear elements (291) can be similar to the material for the elements (264, 275, 286) of the components (281, 26, 27).

[0174] Likewise, it is also possible to manufacture the teeth (29) from a solid material. In this case, the SMC already described above is suitable for the material of the teeth (29).

[0175] An additional advantage of soft magnetic powder composite materials is that they have excellent ability for three-dimensional magnetic flux transfer, have high electrical resistance and high permeability, and therefore have virtually no eddy current losses. In particular, the ability for three-dimensional magnetic flux transfer without high eddy current losses during the process ensures that soft magnetic powder composite materials are used for the gear (29).

[0176] Because soft magnetic powder composite materials have relatively high hysteresis losses, in some embodiments, soft magnetic powder composite materials are used to manufacture the teeth (29). As a result, a balance is found between the reduction of eddy current losses, particularly at locations where eddy current losses are high, and the undesirable effects of the powder composite material on the magnetic circuit.

[0177] FIG. 9 shows a perspective view of a third embodiment of a segment (281) on which a stator pole (25) is placed.

[0178] In the third embodiment, several differences from the first and second embodiments may be observed. First, the radial extension of the radial portion (282) is smaller than in the previous embodiments. Conversely, the radial extension of the connecting leg (26) must be increased. The individual extensions of the radial portion (282) and the connecting leg (26) should be understood as exemplary in this embodiment. The first contact surface (263) may be radially displaced at will. This embodiment results in that, in this exemplary embodiment, at least one concentrated winding (61) is placed around both the radial portion (282) and a portion (26a) of the connecting leg (26).

[0179] An additional difference in this embodiment is that the end face (272) has a shape transition (2723) designed as a step at the edge (2721) (Fig. 4) that forms the transition to the pole piece surface (273) here. In other words, the edge (2721) located at the axial upper end of the end face (272) of the pole piece (27) and likewise forming the radially inner edge of the pole piece surface (273) has a shape transition (2723).

[0180] Since the pole piece (27) is designed in a stacked manner from pole elements (275) stacked in the axial direction (A), the shape transition portion (2723) is designed such that at least one of the pole elements (275) located at the axial top of the pole piece (27) has a smaller extension in the radial direction (R) than the other pole elements (275). In other words, at least one pole element (275) is retracted from the rotor (3) compared to the other pole elements (275) when viewed in the radial direction (R), that is, at a greater distance from the rotor (3) than the other pole elements (275).

[0181] On the other hand, the shape transition portion (2723) can likewise be understood to mean that the transition from the end face (272) to the pole piece surface (273) has a predetermined radius at the edge (2721). Thus, the edge (2721) may be broken.

[0182] Another difference in this embodiment is that the end face (272) has a number of slots (2724) that extend in the axial direction (A).

[0183] A first number of slots (2724), more precisely four pieces, extend axially (A) from the bottom surface (274) of the pole piece, and a second number of slots (2724), likewise four pieces, extend axially (A) from the surface (273) of the pole piece in the opposite direction to the first number of slots (2724). These two numbers of slots (2724) do not come into contact with each other at the center of the end face (272), and as a result, a number of pole elements (275) are not captured by the slots (2724). However, an embodiment in which the slots (2724) extend across all pole elements (275) is also possible. In this embodiment, the number of slots (2724) should be understood as merely exemplary and likewise may be more or fewer.

[0184] In this embodiment, the slots (2724) are arranged parallel to or nearly parallel to each other on the end face (272). Arranging multiple slots (2724) parallel to each other is advantageous because they are also arranged parallel to or at least nearly parallel to the path of the magnetic field, and thus do not block the magnetic field.

[0185] Electrical insulation is achieved by introducing a slot (2724) into the end face (272) of the pole piece (27). That is, the slot (2724) ensures that the eddy current path within the pole element (275) is interrupted and thus blocked. Thus, eddy currents formed by the magnetic field generated from the pole element (275) in the axial direction (A) can be prevented. This results in only a small amount of eddy current remaining within the pole piece (27), and the eddy current loss throughout the pole piece (27) is significantly reduced overall.

[0186] The formation of the slot (2724) can be performed by various methods. These include, in particular, mechanical methods such as milling, punching, or cutting, the latter also include laser and / or water jet cutting and / or wire discharge.

[0187] FIG. 10 shows a perspective view of a fourth embodiment of a segment (281) having a first winding shape, on which a stator pole (25) is disposed thereon.

[0188] In the following, additional embodiments of segment (281) are illustrated in FIGS. 10 through 12. Only differences from previous embodiments are described. Identical or functionally equivalent parts of the additional embodiments are referred to by the same reference numerals as in the previous embodiments. In particular, the reference numerals have the same meaning as those already described in relation to the previous embodiments. It is understood that all descriptions of the previous embodiments apply to the additional embodiments in the same or correspondingly similar manner. It is understood that the features illustrated in the embodiments may be combined with each other in any way.

[0189] Each segment (281) has a first segment end (287) and a second segment end (288) in the circumferential direction. The segment (281) has a first shape at the first segment end (287), in this case a semicircular shape, and a second shape at the second segment end, in this case also a semicircular shape, so that the first shape and the second shape are complementary shapes. In other words, the first shape is a male shape at the second end (288), and the second shape is a female corresponding shape at the first end (287).

[0190] This means that the two shapes are designed such that the first segment end (287a) (see FIG. 13) can be connected in a shape-interlocking manner to the second segment end (288c) of the first adjacent segment (281c), and the second segment end (288a) can be connected in a shape-interlocking manner to the first segment end (287b) of the adjacent second segment (281b). Thus, the first shape and the second shape are designed as two geometric shapes that interlock with each other.

[0191] These embodiments have the advantage that there is a certain flexibility when joining individual segments (281), so that, for example, they can be moved relative to each other when necessary. This also facilitates the replacement of individual segments (281). In these embodiments, because the edge of the first shape is pulled forward in a tangential direction that contacts the circumferential direction, the radial (R) displacement between two adjacent segments (281) is reduced.

[0192] FIG. 11 shows a perspective view of a fifth embodiment of a segment (281) having a first winding shape, on which a stator pole (25) is disposed.

[0193] This embodiment is very similar to the fourth embodiment, the difference being that the edge of the first shape being pulled forward is formed less prominently, thereby improving the movement of individual segments (281) between two adjacent segments (281), and thus enabling a more flexible arrangement of the entire back iron (28). In particular, if the magnetic levitation device (1) needs to be installed in a specific housing, the increased flexibility can facilitate installation. In fact, larger manufacturing tolerances may also be possible in the manufacture of the housing and / or segments.

[0194] FIG. 12 shows a perspective view of a sixth embodiment of a segment (281) having a first winding shape, on which a stator pole (25) is disposed.

[0195] In these embodiments, the first shape and the second shape have a stepped shape in the axial direction (A), and the steps at the first and second segment ends (287, 288) are designed to be complementary to each other so that these segments (281) can be joined with adjacent segments (281).

[0196] Hereinafter, additional exemplary embodiments of a magnetic levitation device (1) according to the present invention are illustrated in FIGS. 13 through 15. Only differences from the first exemplary embodiment are described. Identical or functionally equivalent parts of the additional exemplary embodiments are referred to by the same reference numerals as in the first exemplary embodiment. In particular, the reference numerals have the same meaning as those already described in relation to the first exemplary embodiment. It is understood that all prior descriptions of the first exemplary embodiment apply to the additional exemplary embodiments in the same or correspondingly similar manner. It is understood that the features illustrated in the exemplary embodiments may be combined with one another in any manner.

[0197] FIG. 13 illustrates a schematic cross-sectional view of a second exemplary embodiment of a magnetic levitation device (1) according to the present invention. In this exemplary embodiment, the segment (281) is designed according to the sixth embodiment shown in FIG. 12. Here, three segments (281a, b, c) are shown as an example to show how they are connected to each other at the segment ends.

[0198] FIG. 14 illustrates a cross-sectional view of a third exemplary embodiment of a magnetic levitation device (1) according to the present invention. In this exemplary embodiment, the back iron (28) is designed as a single unit and has a circumferential portion (283). For better visibility and representation, in this embodiment, only three of the stator poles (25) are shown together with the windings (61). It is understood that for the normal operation of the magnetic levitation device (1), at least one winding (61) is attached to all stator poles (25).

[0199] The manufacture of such a magnetic levitation device (1) is advantageous because the number of individual components required in this case is small. First, a back iron (28) having a circumferential portion (283) and a desired number of radial portions (282) is manufactured. This component can be imagined as a wheel having spokes that do not extend to the center ("hub") of the wheel. Subsequently, a winding (61) is placed on each radial portion (282). Subsequently, a connecting leg (26) and a pole piece (27) are attached using the manufacturing method described above. Depending on the manufacturing method, it is also possible for the connecting leg (26) and the pole piece (27) to be already connected to each other and / or designed as a single unit, and subsequently attached to the radial portion (282) as a single common part.

[0200] FIG. 15 illustrates a cross-sectional view of a fourth exemplary embodiment of a magnetic levitation device (1) according to the present invention. In this exemplary embodiment, the segment (281) is designed according to the fourth embodiment shown in FIG. 10. Furthermore, each segment (281) has a bore (289) and a curvature (290) penetrating the segment (281) in the axial direction (A).

[0201] The bore (289) may serve to secure the magnetic levitation device (1) or segment to a base, for example, a housing, using fastening means such as screws or rivets. The location of the bore (289) should be understood as exemplary and may be placed at other locations on the segment (281). The curved section (290) is advantageous, for example, when the magnetic levitation device (1) is installed in a very narrow (precision-fitting) housing. Now, these may be used, for example, as a passage for cables or for better distribution so that the casting composite can flow around the entire stator (2).

[0202] In another exemplary embodiment having a first and second segment having a round or semi-round shape as illustrated in FIGS. 10 to 12, a ring may be attached to the back iron at the radially outer side of the back iron (28) to provide stability or fixation. This serves as a clamping ring or tension ring and may be, for example, a steel band.

[0203] In this exemplary embodiment, the magnetic levitation device (1) further includes a plurality of sensors (4) for determining, for example, the rotor position and / or the rotation angle of the rotor. In this case, one sensor (4) is placed between each second stator pole (25). In this embodiment, the placement of the sensors (4) should be understood as merely exemplary. The sensors (4) may also be placed at other locations on the magnetic levitation device (1). Additionally, the number of sensors (4) should also be understood as exemplary, and there may be more or fewer sensors (4) on the magnetic levitation device (1).

[0204] FIG. 16 illustrates a schematic diagram of the wiring of a magnetic levitation device according to the present invention for control and regulation. A 6-phase winding array is shown in a), and a 12-phase winding array is shown in b).

[0205] The winding array of a) includes a first three-phase winding set (500) and a second three-phase winding set (501), and the two winding sets (500, 501) are designed to be electrically isolated from each other and together form a six-phase wiring system. Each winding set includes six windings (61).

[0206] Each set of windings (500, 501) is preferably designed as a star connection and has individual star points (502) where the associated windings (61) are connected to each other.

[0207] Furthermore, each set of windings (500, 501) includes two windings (61) connected in series in each case, and since they form a phase, there is one series winding for each phase. The windings (61) are connected in a preferred orientation to ensure defined magnetic polarity and symmetric field distribution within the system.

[0208] In a preferred embodiment, two windings connected in series are wired with opposite polarity, that is, they have opposite winding directions.

[0209] The winding array of b) includes four individual sets of three-phase windings (600, 601, 602, 603), which together form a 12-phase system.

[0210] Each of the four sets of windings (600, 601, 602, 603) is preferably designed as a star connection, and in each case, three associated windings (61) have their own star points (604) that are electrically connected to each other. The star points (604) of the individual sets of windings (600, 601, 602, 603) are particularly preferably electrically insulated from each other, so that a total of four separate star points (604) are formed.

[0211] Each set of windings (600, 601, 602, 603) includes three windings (61), and in each case, a single winding (61) is provided for each phase.

[0212] FIG. 17 illustrates a cross-sectional view of a magnetic levitation device according to the present invention, in which a pump unit is inserted therein.

[0213] In FIG. 17, a pump unit (300) is inserted into a magnetic levitation device (1) according to the present invention, and the pump unit (300) includes a rotor (3). The pump unit (300) includes a pump housing (310) having an inlet (311) and an outlet (312) for fluid to be transferred. The rotor (3) is placed within the pump housing (310) and has a plurality of vanes (32) for transferring fluid. The pump housing (310) partitions a pump chamber (313). Furthermore, the pump housing (310) has a cover portion (314) and a base portion (315), and the base portion (315) has a cylindrical cup (316) for receiving the rotor (3). Thus, the cup (316) is inserted into a cup-shaped recess (211) of the stator (2).

[0214] Based on the representation of this drawing, it can be clearly seen why the offset between the back iron (28) and the pole piece surface (273) is advantageous.

[0215] The pump unit (300) can be inserted into the cup-shaped recess (211) to fit precisely, thereby achieving a flat surface (22) of the stator housing (21). Furthermore, as a result of the offset (V) between the pole piece (27) and the back iron (28), the rotor (3) is lifted as high as possible relative to the axial upper surface (22) of the stator housing (21) in the axial direction (A), that is, further away from the second end (AE2) of the stator (2) in the axial direction (A). By lifting the rotor (3) as high as possible in the axial direction (A), the rotor (3) can be designed to be more compact, and as a result, the stability of the rotor (3)'s buoyancy within the stator (2) is improved.

[0216] In particular, when the pump unit (300) or rotor (3) is used as a fluid mixer, the vane (32) may have a smaller extension in the axial direction (A), and as a result, the force acting on the vane (32) from further up in the axial direction (A) is prevented. As a result, the tilting moment is reduced and the lifting of the rotor (3) is ensured well and reliably.

[0217] FIG. 18 shows a cross-sectional perspective view of a magnetic levitation device according to the present invention, in which a mixing unit is inserted therein.

[0218] In FIG. 18, a mixing unit (400) is inserted into a magnetic levitation device (1) according to the present invention, and the mixing unit (400) includes a rotor (3). The mixing unit (400) includes a mixing vessel (410) (partially illustrated herein) which typically has an inlet and an outlet (not shown herein; the inlet and outlet are often combined) for a substance to be mixed, e.g., a fluid. The rotor (3) is placed within the mixing vessel (410) and has a plurality of vanes (32) for mixing the substance. At the axial lower end of the mixing vessel (410), the mixing vessel has a cylindrical cup (411) for receiving the rotor (3). Thus, the cup (411) is inserted into a cup-shaped recess (211) of the stator (2).

[0219] Based on the representation of this drawing, it can be clearly seen why the offset between the back iron (28) and the pole piece surface (273) is advantageous.

[0220] The mixing unit (400) can be inserted into the cup-shaped recess (211) to fit precisely, thereby achieving a flat surface (22) of the stator housing (21). Furthermore, as a result of the offset (V) between the pole piece (27) and the back iron (28), the rotor (3) is lifted as high as possible relative to the axial upper surface (22) of the stator housing (21) in the axial direction (A), that is, further away from the second end (AE2) of the stator (2) in the axial direction (A). By lifting the rotor (3) as high as possible in the axial direction (A), the rotor (3) can be designed to be more compact, and as a result, the stability of the rotor (3) in the stator (2) is improved.

[0221] When the mixing unit (400) or rotor (3) is used as a fluid mixer, the vane (32) may have a smaller extension in the axial direction (A), and as a result, the force acting on the vane (32) from further up in the axial direction (A) is prevented. As a result, the tilting moment is reduced and the lifting of the rotor (3) is ensured well and reliably. It is evident that all exemplary embodiments and examples illustrated in the description of the drawings can be combined with each other in any form with their individual features and components.

Claims

Claim 1 A magnetic levitation device for non-contact magnetic levitation of a rotor (3) having a disc-shaped or ring-shaped magnetically active core (31), wherein the magnetic levitation device comprises a stator (2) that extends in an axial direction (A) and has a cup-shaped recess (211) disposed at a first axial end of the stator (2) into which the rotor (3) can be inserted, and wherein the stator (2) has a back iron (28), and the back iron (28) comprises a plurality of radial parts (282), at least one circumferential part;283), back iron bottom surface (284) and back iron surface (285), each radial portion (282) extends radially (R) perpendicular to the axial direction (A) from the at least one circumferential portion (283), the back iron surface (285) faces the first axial end (AE1) of the stator (2), and the back iron bottom surface (284) faces the second axial end of the stator (2), the stator (2) has a plurality of stator poles (25), each of the stator poles has a connecting leg (26) and a pole piece (27), each connecting leg (26) extends from a first end (261) to a second end (262), the first end (261) contacts the back iron (28), and each pole piece (27) is the connecting A magnetic levitation device having a contact surface (271) in contact with a second end (262) of a leg (26), each pole piece (27) extends radially (R) from the contact surface (271) to an end face (272), all end faces (272) are arranged around the cup-shaped recess (211), at least one concentrated winding (61) is arranged on each radial portion (282), the concentrated winding surrounds the individual radial portion (282), and each connecting leg (26) extends radially inward from the first end (261) to the second end (262) obliquely with respect to the axial direction (A), thereby causing the back iron surface (285) and the pole piece surface (273) of the pole piece (27) to be arranged with an offset (V) with respect to the axial direction (A). Claim 2 A magnetic levitation device according to claim 1, wherein the back iron (28) comprises a plurality of segments (281), each segment (281) having a radial portion (282) and a circumferential portion (283). Claim 3 A magnetic levitation device according to claim 1 or 2, wherein the stator (2) has twelve stator poles (25), the rotor (3) has a plurality of rotor poles, preferably eight rotor poles, and the rotor poles are configured as four pairs of poles. Claim 4 A magnetic levitation device according to any one of claims 1 to 3, wherein at least one concentrated winding (61) has a conical structure. Claim 5 A magnetic levitation device according to any one of claims 1 to 4, wherein the at least one concentrated winding (61) has a radial first end (611) and a radial second end (612), wherein the radial first end (611) faces the circumferential portion (283) and the radial second end (612) faces the cup-shaped recess (211), and the at least one concentrated winding (61) has a first outer diameter (WA1) at the radial first end (611) and a second outer diameter (WA2) at the radial second end (612), wherein the first outer diameter (WA1) is larger than the second outer diameter (WA2). Claim 6 A magnetic levitation device according to any one of claims 1 to 5, wherein the end face (272) of the pole piece (27) is configured as a curved surface, and the curved portion of the end face (272) is preferably configured coaxially with respect to the cup-shaped recess (211). Claim 7 A magnetic levitation device according to any one of claims 1 to 6, wherein the end face (272) is configured to be wider in the circumferential direction than the maximum range of the contact surface (271) in the circumferential direction. Claim 8 A magnetic levitation device according to any one of claims 1 to 7, wherein the end face (272) has a shape transition portion (2723), preferably a rounding off or a step, on an edge (2721) that constitutes a transition to the pole piece surface (273). Claim 9 A magnetic levitation device according to any one of claims 1 to 8, wherein the back iron (28) is formed in a stacked manner from back iron elements (286), and the back iron elements (286) are stacked in the axial direction (A). Claim 10 A magnetic levitation device according to any one of claims 1 to 9, wherein the connecting leg (26) is formed in a stacked manner from elements (264), and the elements (264) are stacked in the circumferential direction of the stator (2). Claim 11 A magnetic levitation device according to any one of claims 1 to 10, wherein the pole piece (27) is formed in a stacked manner from pole elements (275), and the pole elements (275) are stacked in the axial direction (A). Claim 12 A magnetic levitation device according to any one of claims 1 to 9, wherein the connecting leg (26) and the pole piece (27) are integrally formed as a tooth (29), the tooth (29) is formed in a stacked manner from tooth elements (291), the tooth elements (291) are stacked in the circumferential direction of the stator (2), and / or the tooth (29) is formed from a soft magnetic material. Claim 13 A magnetic levitation device according to any one of claims 1 to 12, wherein the stator (2) is configured to generate torque capable of magnetically driving the rotor (3) in a non-contact manner for rotation around the axial direction (A). Claim 14 In claim 13, the magnetic levitation device comprises an electromagnetic rotary drive unit, a mixing device, a centrifuge, a cross-flow fan, a rotary filter, or a viscometer. Claim 15 A pump unit for a magnetic levitation device (1) according to any one of claims 1 to 14, wherein the pump unit (300) comprises a rotor (3), the pump unit (300) comprises a pump housing (310) having an inlet (311) and an outlet (312) for fluid to be transported, the rotor (3) is disposed within the pump housing (310), the rotor (3) comprises a plurality of vanes (32) for transporting fluid, the pump housing (310) comprises a pump chamber (313), the pump housing (310) comprises a cover portion (314) and a base portion (315), the base portion (315) comprises a cylindrical or conical cup (316) for receiving the rotor (3), and the cup (316) can be inserted into a cup-shaped recess (211) of the stator (2). pump unit.

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