Magnetic suspension device and electromagnetic rotary driver

Abstract

The invention relates to a magnetic levitation device for contactless magnetic levitation of a rotor comprising a disc-shaped or annular magnetic effect core, the magnetic levitation device having a stator comprising a plurality of coil cores, each coil core being made of elements in the form of sheet metal, the elements being stacked in the circumferential direction of the stator, wherein each coil core has a first lateral boundary surface and a second lateral boundary surface, where each coil core comprises a longitudinal leg and a transverse leg, where at least one concentrated winding is provided on each longitudinal leg, where the stator further has a cup-shaped recess into which the rotor can be inserted, and wherein at least one of the first lateral boundary surface or the second lateral boundary surface has at least one groove. The invention further relates to an electromagnetic rotary drive having such a magnetic suspension device.

Description

Technical Field

[0001] The invention relates to a magnetic levitation device according to the preambles of the independent patent claims, and to an electromagnetic rotary drive having such a magnetic levitation device. Background Art

[0002] Magnetic bearing devices for contactless magnetic support of rotors have the advantage that they do not require mechanical bearings for the rotor. The rotor is supported or stabilized by means of magnetic forces generated by the stator of the magnetic bearing device. Due to the lack of mechanical bearings, such magnetic bearing devices are particularly suitable for pumping, mixing, centrifuging, or stirring devices with which very sensitive substances are conveyed (e.g., blood pumps), or with which very high purity requirements are placed (e.g., in the pharmaceutical or biotechnology industries), or with which abrasive or corrosive substances are conveyed that would very quickly destroy mechanical bearings (e.g., pumps or mixers for slurries, sulfuric acid, phosphoric acid, or other chemicals in the semiconductor industry).

[0003] In the biotechnology industry, such magnetic bearings are used in conjunction with bioreactors, for example, in centrifugal pumps for transporting fluids into and out of bioreactors, or in mixing devices for mixing fluids within bioreactors. In the semiconductor industry, such magnetic bearings are used not only for transporting aggressive or abrasive substances but also in rotating devices, such as those used to rotate wafers.

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

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

[0006] The characteristic feature of the temple construction is that the stator of the magnetic bearing device has a plurality of coil cores, each of which includes a longitudinal leg extending from a first end in an axial direction to a second end. Here, the axial direction refers to the direction defined by the desired axis of rotation of the rotor supported by the magnetic bearing device. The desired axis of rotation is the axis of rotation about which the rotor rotates in an operating state when the rotor is in a centered and non-tilted position relative to the stator. In addition to the longitudinal legs, each coil core includes a transverse leg (also called a rod), which is arranged at the second end of the longitudinal leg in each case and extends in a radial direction (usually toward the inside), wherein the radial direction is perpendicular to the axial direction. Therefore, the transverse legs extend essentially at right angles to the longitudinal legs. The coil cores each have an L-shape, wherein the transverse legs form the short legs of the L. The rotor to be supported is then arranged between the transverse legs.

[0007] The structure gets its name from the multiple longitudinal legs that extend in an axial direction and are reminiscent of temple columns.

[0008] In one embodiment, the stator of the magnetic bearing arrangement has, for example, six coil cores arranged circularly and equidistantly around a cup-shaped recess into which the rotor can be inserted. The first ends of the longitudinal legs are often connected in the circumferential direction by a back iron, which conducts the magnetic flux. The rotor to be supported includes a magnetic effect core, such as a permanent magnetic disk or a permanent magnetic ring, which is arranged between the radially inner ends of the transverse legs and rotates in the axial direction in the operating state, wherein the rotor is magnetically supported in a contactless manner relative to the stator.

[0009] For such magnetic bearing arrangements, the rotor's magnetic effect core need not necessarily be designed with permanent magnets. Designs are also known in which the rotor's magnetic effect core is designed with no permanent magnets (i.e., without permanent magnets). The rotor's magnetic effect core is, for example, designed with ferromagnetic design and made of, for example, iron, nickel-iron, cobalt-iron, silicon-iron, mu metal, or another ferromagnetic material.

[0010] Furthermore, designs are possible in which the rotor's magnetic core comprises both ferromagnetic and permanent magnet materials. For example, permanent magnets can be placed or inserted into a ferromagnetic matrix. This type of design is advantageous, for example, if one wishes to reduce the cost of a large rotor by conserving permanent magnet material.

[0011] The longitudinal legs carry windings to generate the electromagnetic fields required for contactless magnetic support of the rotor. For example, the windings are designed so that one concentrated winding is wound around each longitudinal leg, i.e., the coil axis of each concentrated winding extends in the axial direction. As is typical for temple designs, the coil axes of the concentrated windings extend in the axial direction and the concentrated windings are not arranged in the radial plane in which the rotor or its magnetically effective core is supported in the operating state.

[0012] A design in which exactly one concentrated winding is arranged on each longitudinal leg is possible. In other designs, several (for example, exactly two) concentrated windings are provided on each longitudinal leg. A design in which a winding is provided that is wound around two longitudinal legs adjacent in the circumferential direction so that both of the two adjacent longitudinal legs are located within the interior space of the concentrated winding is also possible.

[0013] The coil cores of magnetic bearings known from the prior art are often designed as sheet metal. This means that several metal sheets in the shape of the coil core are stacked circumferentially and insulated from one another. The sheet metal design of the coil core prevents eddy currents for magnetic fields extending in the direction of the sheet metal (i.e., in the axial direction along the longitudinal legs and in the radial direction along the transverse legs).

[0014] For magnetic fields emerging laterally (ie in the circumferential direction) from the metal sheets of the longitudinal and transverse legs, the insulation of the metal sheets is ineffective and therefore eddy currents still occur because these magnetic fields pass orthogonally through the metal sheets.

[0015] Especially with regard to magnetic bearing arrangements with a large magnetic gap, where the magnetic gap is defined as the distance in radial direction between the end faces of the transverse legs and the magnetic effect core of the rotor, the orthogonal field components cannot be neglected and generate significant eddy current losses.

[0016] In the context of this application, a large magnetic gap means a magnetic gap that is greater than 1% of the diameter of the magnetic effect core in the radial direction. In some cases, the magnetic gap may be greater than or equal to 5% of the diameter of the magnetic effect core in the radial direction. Summary of the Invention

[0017] Therefore, based on this prior art, the object of the present invention is to provide a magnetic levitation device for contactless magnetic levitation of a rotor having a disk-shaped or annular magnetic effect core, the magnetic levitation device having lower eddy current losses than the prior art.

[0018] Furthermore, the object of the present invention is to provide an electromagnetic rotary drive having such a magnetic levitation device.

[0019] The subject matter of the invention which meets this object is characterized by the features of the independent patent claims.

[0020] According to the present invention, a magnetic levitation device for contactless magnetic levitation of a rotor is proposed, the rotor comprising a disk-shaped or annular magnetic effect core, wherein the magnetic levitation device has a stator comprising a plurality of coil cores, wherein each coil core is made of an element in the form of a metal sheet, wherein the elements are stacked in the circumferential direction of the stator, wherein each coil core has a first lateral boundary surface and a second lateral boundary surface, wherein each coil core comprises a longitudinal leg and a transverse leg, wherein the longitudinal leg extends from a first end in the axial direction to a second end, and wherein the transverse leg is arranged at the second end of the longitudinal leg and extends in a radial direction perpendicular to the axial direction, wherein at least one concentrated winding is provided on each longitudinal leg, the at least one concentrated winding being wrapped around the corresponding longitudinal leg, wherein the stator further comprises a cup-shaped recess into which the rotor can be inserted, wherein the cup-shaped recess is arranged at an axial end of the stator, wherein the transverse leg is arranged around the cup-shaped recess, and wherein at least one of the first lateral boundary surface or the second lateral boundary surface has at least one slot.

[0021] The provision of slots in at least one of the two lateral boundary surfaces of the coil core provides electrical insulation. This means that the at least one slot ensures that the path of eddy currents in the coil core is interrupted and thus blocked. Consequently, only small eddy currents remain in the coil core, and eddy current losses in the coil core are significantly reduced overall. Advantageously, the at least one slot should extend parallel to, or at least approximately parallel to, the course of the magnetic field in the coil core so as not to obstruct this course.

[0022] Many different methods can be used to produce the grooves. These methods include, among others, mechanical processes such as milling, punching or cutting, whereby the latter also includes the use of lasers or water jet cutting machines.

[0023] According to a preferred embodiment, the element is made of electrical sheet metal. According to a general definition, electrical sheet metal is understood to be a soft magnetic material used for magnetic cores. There is also the possibility of using mu metal alloys.

[0024] According to a preferred embodiment, the at least one slot extends only in the transverse leg. For applications where the coil core must have high stability, it can be advantageous if the at least one slot extends only in the transverse leg. This embodiment also reduces some eddy current losses, since the majority of the effects that cause eddy current losses occur in the region of the second end.

[0025] According to a preferred embodiment, at least one slot extends in both the transverse leg and the longitudinal leg. This is advantageous in order to further reduce eddy current losses in the coil core. The extent to which the at least one slot extends in the longitudinal leg in the axial direction toward the first end of the longitudinal leg is variable. All lengths of the at least one slot are possible, from a minimum extension of 5% of the total length of the longitudinal leg in the axial direction to an extension toward the first end of the longitudinal leg.

[0026] In a preferred embodiment, at least one groove has a rounding which redirects the groove from a radial direction to an axial direction.

[0027] According to a preferred embodiment, at least one groove extends from the first lateral boundary surface to the second lateral boundary surface.

[0028] In a preferred embodiment, the extension of at least one slot is shorter than the distance of the first lateral boundary surface from the second lateral boundary surface when viewed in the circumferential direction of the stator.

[0029] In other words, the at least one slot does not extend through the entire coil core in the circumferential direction of the stator. This means that the at least one slot is not provided in any element of the sheet metal design of the coil core. This is advantageous because the majority of eddy currents occur in elements arranged directly at or near the two lateral boundary surfaces. Therefore, the path of eddy currents in the coil core is interrupted by the at least one slot at the point where eddy currents most frequently occur. This ensures a significant reduction in eddy current losses. Furthermore, this embodiment contributes to the stability of the coil core.

[0030] According to a preferred embodiment, several grooves are provided, which are arranged parallel to one another or at least approximately parallel to one another.

[0031] An arrangement of several slots parallel to one another or at least approximately parallel to one another is advantageous, since they then also extend parallel to or at least approximately parallel to the course of the magnetic field in the coil core, so that they do not block this course.

[0032] Furthermore, it is preferred that the coil core has a rounded portion at the upper axial end, which redirects the coil core from the axial direction into the radial direction.

[0033] For example, in the case of an L-shaped coil core, in which the long portion of the "L" is formed by the longitudinal legs and the short portion of the "L" is formed by the transverse legs, when viewed from the cup-shaped recess, the radially outer edges of the transverse legs extending in the circumferential direction in a radial plane are designed to be rounded. This embodiment has the advantage of having lower eddy current losses and is also easier to implement in terms of construction.

[0034] In a preferred embodiment, a back iron is arranged at the first ends of the longitudinal legs, which back iron connects the first ends of all longitudinal legs, wherein the back iron is designed in an annular manner with a metal strip extending from a radially inner start end to a radially outer end, wherein the strip forms several strip windings lying next to each other with respect to the radial direction.

[0035] According to a preferred embodiment, two concentrated windings are provided on each longitudinal leg, each of the two concentrated windings wrapping around a respective longitudinal leg and being arranged adjacent to each other with respect to the axial direction.

[0036] Furthermore, it is preferred that at least one groove is provided in each case both in the first lateral boundary surface and in the second lateral boundary surface.

[0037] This is advantageous because the majority of eddy currents occur particularly in elements located directly adjacent to the two lateral boundary surfaces. Therefore, the path of the eddy currents in the coil core is interrupted by at least one slot at each location where eddy currents most frequently occur. This ensures a significant reduction in eddy current losses.

[0038] According to a particularly preferred embodiment, the stator of the magnetic levitation device is designed to generate a torque with which the rotor can be driven magnetically in a contactless manner for rotation about the axial direction.

[0039] Here, the stator is designed as a bearing and drive stator, which is both an electrically driven stator and a magnetically suspended stator. A rotating magnetic field can be generated using the stator's electrical windings. On the one hand, this rotating magnetic field exerts a torque on the rotor, which causes it to rotate about the desired axis of rotation. On the other hand, this rotating magnetic field exerts an adjustable lateral force on the rotor, making it possible to actively control or adjust its radial position.

[0040] Furthermore, the invention proposes an electromagnetic rotary drive designed as a temple motor, wherein the electromagnetic rotary drive comprises a magnetic levitation device according to the invention and a rotor having a disk-shaped or annular magnetic effect core, wherein the rotor can be inserted into the cup-shaped recess, and wherein the rotor is designed as a rotor of the electromagnetic rotary drive.

[0041] Such electromagnetic rotary drives are also referred to as bearingless motors. The term bearingless motor refers to electromagnetic rotary drives in which the rotor is completely magnetically suspended relative to the stator, without separate magnetic bearings being provided.

[0042] Further advantageous measures and embodiments of the invention are apparent from the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In the following, the invention will be explained in more detail with reference to an embodiment and with reference to the accompanying drawings. In the drawings:

[0044] Figure 1 : A perspective view of a first embodiment of a magnetic levitation device according to the present invention,

[0045] Figure 2 :From Figure 1 A perspective view of a single coil core of a magnetic levitation device,

[0046] Figure 3-Figure 6 : Different variants of embodiments for a coil core, each in a perspective view,

[0047] Figure 7 : A perspective view of a second embodiment of a magnetic levitation device according to the present invention, and

[0048] Figure 8 : Schematic cross-sectional view of an embodiment for a stator housing. DETAILED DESCRIPTION

[0049] Figure 1A perspective view of an embodiment of a magnetic levitation device 1 according to the present invention is shown, which is designated as a whole by the reference numeral 1. The magnetic levitation device 1 is designed for contactless magnetic levitation of a rotor 3, which includes a disk-shaped or annular magnetic effect core 31. The magnetic levitation device 1 is designed according to a temple structure and includes a stator 2. Generally, the stator 2 includes a stator housing 21 ( Figure 8 ), however, for reasons of better overview, the stator housing 21 is not shown in Figure 1 For this reason, Figure 8 An exemplary embodiment of a stator housing 21 is shown in a schematic sectional view.

[0050] A cup-shaped recess 211 is provided at one axial end of the stator housing 21, into which the rotor 3 can be inserted. The rotor 3 is designed to rotate about a desired rotation axis. The desired rotation axis defines an axial direction A. Typically, the central axis of the stator 2 extending in the axial direction A coincides with the desired rotation axis. Figure 1 The desired axis of rotation, indicated in , designates the axis about which the rotor 3 rotates in the operating state when the rotor 3 is in a centered and non-tilted position relative to the stator 2 .

[0051] The stator 2 has a plurality of coil cores 25, here six coil cores 25, each of which is made of a sheet metal element 253. The elements 253 are stacked in the circumferential direction of the stator 2, and each coil core 25 has a first lateral boundary surface 255 and a second lateral boundary surface 256. The circumferential direction refers to a direction perpendicular to the radial direction R and perpendicular to the axial direction A. Furthermore, each coil core 25 includes a longitudinal leg 26 extending from a first end 261 in the axial direction A to a second end 262, and a transverse leg 27 arranged at the second end 262 of the longitudinal leg and extending in a radial direction perpendicular to the axial direction A.

[0052] For a better understanding, from Figure 1 A perspective view of a single coil core 25 of the magnetic levitation device 1 is shown in Figure 2 middle.

[0053] The coil cores 25 of the stator 2 are arranged equidistantly on a circular line so that when the rotor 3 is inserted into the cup-shaped recess 211 , the transverse legs 27 surround the magnetic effect core 31 of the rotor 3 .

[0054] In this embodiment, the coil core 25 has a rounded portion 257 at the axial upper end 252, which redirects the coil core 25 from the axial direction A to the radial direction R. The coil core 25 has an outer edge 258 ( Figure 4). This means that, in this embodiment, the radially outer edge 258 at the axially upper end 252 of the coil core 25 is a broken edge or rounded edge, as indicated by the rounded portion 257. Depending on the embodiment of the coil core 25, the rounded portion 257 may extend only in the region of the longitudinal legs 26, only in the region of the transverse legs 27, or in the region of both the longitudinal legs 26 and the transverse legs 27. This has the advantage that this embodiment of the coil core 25 has lower eddy current losses and is also easier to implement in terms of construction.

[0055] At least one concentrated winding 61 is arranged at each longitudinal leg 26, and at least one concentrated winding 61 is wrapped around the corresponding longitudinal leg 26. In other embodiments, more than one concentrated winding 61 may also be arranged at the longitudinal leg 26. For example, there is such a concentrated winding 61 at Figure 1 , in which exactly two concentrated windings 61 a, 61 b ​​are provided in each case on each of the longitudinal legs 26, each of exactly two concentrated windings 61 a, 61 b ​​wrapping around the respective longitudinal leg 26, wherein the two windings 61 a, 61 b ​​arranged on the same longitudinal leg 26 are arranged adjacent to one another with respect to the axial direction A.

[0056] The concentrated windings 61a, 61b are used to generate an electromagnetic field, by which the rotor 3 can be magnetically suspended in the cup-shaped recess 211 without contact ( Figure 8 ).

[0057] Element 253 can be made of electrical sheet metal. According to the general definition, electrical sheet metal is understood to be a soft magnetic material used for magnetic cores. There is also the possibility of using a mu metal alloy for the strips.

[0058] The number of elements 253 in all embodiments and figures is to be understood as purely exemplary. The number may be greater or less than that indicated.

[0059] exist Figure 1 In the first embodiment of the magnetic levitation device 1 according to the invention, shown in FIG, three slots 254 are arranged in each case in both the first lateral boundary surface 255 and the second lateral boundary surface 256. The slots 254 extend both in the transverse leg 27 and in the longitudinal leg 26. The insertion of the slots 254 in the two lateral boundary surfaces 255, 256 of the coil core 25 provides electrical insulation. This means that the slots 254 ensure that the eddy current paths in the coil core 25 are interrupted and thus blocked. Consequently, only small eddy currents remain in the coil core 25, and the eddy current losses in the coil core 25 as a whole are significantly reduced.

[0060] In this embodiment, each of the slots 254 has a rounding 2541 that redirects the respective slot 254 from the radial direction R to the axial direction A. The slots 254 are arranged parallel or at least approximately parallel to one another and parallel or at least approximately parallel to the course of the magnetic field in the coil core 25. This has the advantage that the slots 254 do not hinder and / or block the course of the magnetic field in the coil core 25.

[0061] Here, the slot 254 does not extend over the entire extension of the longitudinal leg 26 in the axial direction A, but rather only partially and ends before the axial upper end of the concentrated winding 61 a.

[0062] Furthermore, however, at least one of the slots 254 has a greater Figure 2 Embodiments that extend beyond the embodiment shown in FIG. 1 are also possible. Such possible embodiments are shown in FIG. Figure 3 The perspective view of a variant of the embodiment of the coil core 25 shows the maximum possible extent of the slot 254 in the coil core 25 .

[0063] Of course, it is possible that the slot 254 can have any extension length in the longitudinal leg 26. It is also possible that the slot 254 also extends only in the transverse leg 27.

[0064] In this embodiment, the slots 254 extend shorter than the distance between the first lateral boundary surface 255 and the second lateral boundary surface 256 when viewed in the circumferential direction of the stator 2. In other words, the slots 254 do not penetrate all elements 253 of the coil core 25, but only a certain number of elements 253. In this embodiment, there are eight elements 253 per coil core 25, i.e., four elements 253 in each case when viewed from each lateral boundary surface 255, 256.

[0065] This is advantageous because the majority of eddy currents occur particularly in elements 253 that are arranged directly on or close to the two lateral boundary surfaces 255, 256. Consequently, the path of eddy currents in coil core 25 is interrupted by slots 254 at the locations where eddy currents most frequently occur. This ensures a significant reduction in eddy current losses. Furthermore, the incomplete penetration of slots 254 through all elements 253 of coil core 25 contributes to the stability of coil core 25.

[0066] However, embodiments are also possible in which the groove 254 extends from the first lateral boundary surface 255 to the second lateral boundary surface 256 .

[0067] According to a particularly preferred embodiment, the stator 2 is designed so that, in addition to the contactless magnetic levitation of the rotor 3, it can also exert a torque on the rotor 3 or the magnetic effect core 31 of the rotor 3, which drives the rotor 3 in rotation about the desired axis of rotation. This means that, in this preferred embodiment, the rotor 3 can be driven for rotation about the axial direction A.

[0068] In this embodiment, the concentrated windings 61 therefore generate an electromagnetic rotating field, with which the rotor 3 can be both magnetically levitated relative to the stator 2 and driven for rotation about the axial direction A in a contactless manner.

[0069] It is understood that the number of six coil cores 25, while preferred, is to be understood only as an example. Of course, embodiments in which the stator 2 has fewer than six coil cores 25 (e.g., five, four, or three coil cores 25) are also possible, or embodiments in which the stator 2 has more than six coil cores 25 (e.g., seven, eight, nine, or twelve coil cores 25, or any larger number of coil cores 25) are also possible.

[0070] The rotor 3 comprises a magnetic effect core 31 which is designed in a ring or disk-shaped manner. Figure 1 As shown in FIG, the magnetic effect core 31 is designed as a ring and defines a magnetic center plane. Alternatively, the magnetic effect core 31 can also be designed as a disk. Generally, in the case of a disk-shaped or ring-shaped magnetic effect core 31, the magnetic center plane is the geometric center plane of the magnetic effect core 31 of the rotor 3, which is perpendicular to the axial direction A. In the operating state, the magnetic effect core 31 is suspended in a radial plane perpendicular to the axial direction A.

[0071] Radial plane in Figure 1 The radial plane E is indicated by a line in the radial direction R perpendicular to the axial direction A. The radial plane is the plane perpendicular to the axial direction A and containing the radial direction R. The radial plane is the plane in which the magnetic effect core 31 of the rotor 3 is actively magnetically suspended between the end faces 272 in the stator 2 in the operating state. If the rotor 3 is not tilted and does not deflect in the axial direction A, the magnetic center plane lies in the radial plane E. The radial plane defines the xy plane of a Cartesian coordinate system, whose z-axis extends in the axial direction A.

[0072] The radial position of the magnetic effect core 31 or the rotor 3 refers to the position of the rotor 3 in the radial plane E.

[0073] For sufficient understanding of the present invention, only the magnetic effect core 31 of the rotor 3 is shown. Figure 1 It is understood that the rotor 3 may of course also include additional components, such as a jacket or encapsulation, which is preferably made of plastic, metal or metal alloy or ceramic or ceramic material. In addition, the rotor 3 may also include blades or other components for mixing, stirring or pumping the fluid.

[0074] When the rotor 3 is inserted into the cup-shaped recess 211 ( Figure 8 ), the rotor 3 and in particular the magnetic effect core 31 of the rotor 3 is surrounded by the radially outwardly arranged end faces 272 of the transverse legs 27 of the coil core 25 of the stator 2. The transverse legs 27 thus form a plurality of distinct stator poles, in this case six stator poles.

[0075] When the magnetic effect core 31 of the rotor 3 is in its desired position during operation, it is centered between the end faces 272 of the transverse legs 27. According to the representation, the concentrated windings 61 are arranged below a radial plane and aligned so that their coil axes extend in the axial direction A.

[0076] All first ends 261 of the longitudinal legs 26 (ie, according to the representation ( Figure 1 ) are connected to each other by means of a back iron 28. Preferably, the back iron 28 is designed in an annular manner. Such an embodiment is possible in which the back iron 28 extends radially inwards along all first ends 261 of the longitudinal legs 26 (see, for example, Figure 1 ).

[0077] In order to generate the electromagnetic field required for magnetic levitation of the rotor 3 and optionally for generating a torque on the rotor 3 , the longitudinal legs 26 of the coil core 25 carry a winding designed as a concentrated winding 61 .

[0078] In operation, these concentrated windings 61 generate electromagnetic rotating fields with which any adjustable transverse force in the radial direction can be exerted on the rotor 3 , so that the radial position of the rotor 3 , i.e., its position in a radial plane perpendicular to the axial direction A, can be actively controlled or adjusted. Optionally, these electromagnetic rotating fields can also be used to generate a torque on the rotor 3 .

[0079] The “magnetic effective core 31 ” of the rotor 3 refers to that region of the rotor 3 that magnetically cooperates with the stator 2 for the generation of magnetic levitation forces and optionally for torque generation.

[0080] As already mentioned, in this embodiment, the magnetic effect core 31 is designed in an annular manner. Furthermore, the magnetic effect core 31 is designed in a permanent magnetic manner. For this purpose, the magnetic effect core 31 may include at least one permanent magnet, but may also include several permanent magnets, or, as in the embodiment described here, may consist entirely of permanent magnetic material, so that the magnetic effect core 31 is a permanent magnet. For example, the magnetic effect core 31 is magnetized in the radial direction.

[0081] Ferromagnetic or ferrimagnetic materials that are magnetically hard (i.e., have a high coercive field strength) are typically referred to as permanent magnets. The coercive field strength is the magnetic field strength required to demagnetize the material. Within the framework of this application, a permanent magnet is understood to be a component or material having a total coercive field strength of greater than 10,000 A / m, more precisely, a coercive field strength of the magnetic polarization.

[0082] Such an embodiment is also possible in which the magnetic effect core 31 is designed without permanent magnets (i.e., without permanent magnets). The rotor 3 is then designed, for example, as a reluctance rotor. The magnetic effect core 31 of the rotor 3 is then made, for example, of a soft magnetic material. Suitable soft magnetic materials for the magnetic effect core 31 are, for example, ferromagnetic or ferrimagnetic materials, i.e., in particular, iron, nickel-iron, cobalt-iron, silicon-iron, or mu metal.

[0083] Furthermore, embodiments are possible in which the magnetic effect core 31 of the rotor 3 comprises both ferromagnetic and permanent magnet materials. For example, permanent magnets may be placed or inserted into a ferromagnetic matrix. Such embodiments are advantageous, for example, if one wishes to reduce the cost of a large rotor by saving on permanent magnet material.

[0084] Embodiments are also possible in which the rotor is designed according to the principle of a cage rotor.

[0085] The annular back iron 28 may be made of a soft magnetic material, since it serves as a flux conducting element to conduct magnetic flux. It is also possible that the coil core 25 of the stator 2 is also made of a soft magnetic material.

[0086] Suitable soft magnetic materials for the coil core 25 and the back iron 28 are, for example, ferromagnetic or ferrimagnetic materials, i.e., in particular, iron, nickel-iron, cobalt-iron, silicon-iron, or mu metal. In this case, a design as a stator sheet metal stack is preferred for the stator 2, wherein the back iron 28 is designed in sheet metal, i.e., it consists of several thin sheet metal elements stacked parallel to one another in the axial direction A. All flux-conducting elements are designed identically, i.e., in this case, essentially annular, and also have the same thickness in each case. Thus, the back iron 28 itself is designed essentially annular and, in the assembled state, extends radially inwards along the first end 261 of the longitudinal leg 26.

[0087] An embodiment is also possible in which a so-called tape-wound toroidal core is used as the back iron 28. This is a wound strip 29. Such a design is Figure 7 This is achieved in the second embodiment shown in FIG.

[0088] Furthermore, it is possible for the back iron 28 to consist of compressed and subsequently sintered particles of the aforementioned materials. The metal particles are preferably embedded in a plastic matrix so that they are at least partially insulated from one another, thereby minimizing eddy current losses. Therefore, soft magnetic composites consisting of electrically insulating and compressed metal particles are also suitable for stators. In particular, these soft magnetic composites, also known as SMCs (soft magnetic composites), can consist of iron powder particles coated with an electrically insulating layer. These SMCs are then formed into the desired shape using a powder metallurgy process.

[0089] During operation of the magnetic levitation device 1, the magnetic effect core 31 of the rotor 3 cooperates with the stator 2 in such a manner that the rotor 3 can be magnetically levitated relative to the stator 2 without contact and, preferably, can also be magnetically set to rotate contactlessly about the axial direction A. In this case, it is particularly advantageous if the same windings 61 used to achieve the magnetic levitation of the rotor 3 are also used to generate torque on the rotor 3. Preferably, the three degrees of freedom of the rotor 3 can then be actively adjusted: its position in the radial plane E and its rotation. With respect to its axial deflection in the axial direction A from the radial plane E, the magnetic effect core 31 of the rotor 3 is passively magnetically stabilized by magnetic resistance, i.e., it cannot be controlled. The magnetic effect core 31 of the rotor 3 is also passively magnetically stabilized with respect to the remaining two degrees of freedom: tilting relative to a radial plane perpendicular to the desired axis of rotation. Through the cooperation of the magnetic effect core 31 with the coil core 25, the rotor 3 is thus passively magnetically levitated or passively magnetically stabilized in the axial direction A, resists tilting (a total of three degrees of freedom), and actively magnetically levitated in the radial plane (two degrees of freedom).

[0090] As is generally the case, active magnetic suspension is also referred to in the context of this application as magnetic suspension that can be actively controlled or adjusted, for example, by means of an electromagnetic field generated by concentrated windings 61. Passive magnetic suspension or passive magnetic stabilization is magnetic suspension or magnetic stabilization that cannot be controlled or adjusted. Passive magnetic suspension or stabilization is based on, for example, a magnetic drag force that brings the rotor 3 back into its desired position when it is deflected from its desired position (i.e., for example, when it is indexed or deflected in the axial direction A, or when it is tilted).

[0091] In the magnetic levitation device 1, in contrast to typical magnetic bearings, the magnetic levitation and optionally the generation of a torque acting on the rotor are achieved by means of an electromagnetic rotating field. For the combined generation of the magnetic levitation force and the torque for rotating the rotor 3 about the axial direction A, it is possible, on the one hand, to Figure 7 It is shown that exactly one concentrated winding 61 is arranged on each longitudinal leg 26 .

[0092] On the other hand, embodiments are also possible in which two different winding systems provide for the combined generation of the magnetic levitation force and the torque for rotating the rotor 3. For this purpose, for example, Figure 1As shown in FIG, exactly two concentrated windings 61 a, 61 b ​​are arranged in each case at each longitudinal leg 26, exactly two concentrated windings 61 a, 61 b ​​being arranged adjacent to one another with respect to the axial direction A. One of these two windings 61 a, 61 b ​​belongs to a first winding system of the two winding systems, and the other belongs to a second winding system of the two winding systems.

[0093] exist Figure 7 In the embodiment shown in FIG, in which exactly one concentrated winding 61 is provided at each coil core 25, the values ​​of the current required for suspension and the current required for torque generation, determined in each case, for example, in a control unit, are added or superimposed by calculation (e.g., with the aid of software). The resulting total current is then fed to the respective concentrated winding 61.

[0094] If the stator 2 of the magnetic levitation device 1 according to the invention is designed to generate torque, the magnetic levitation device 1 is suitable for an electromagnetic rotary drive designed as a temple motor. It is also possible that the magnetic levitation device 1 according to the invention is also suitable for other devices, such as centrifugal pumps, mixing devices for mixing flowable substances, stirring devices (e.g., for mixing fluids in tanks), fans, or even devices for supporting and rotating wafers (e.g., in semiconductor production).

[0095] Figure 4 A perspective view shows a further variant of an embodiment of a coil core 25. In this variant, the coil core 25 is not round at the edge 258 but is designed in a rectangular manner. In this embodiment, only one slot 254 extends in the transverse leg 27; no slot 254 extends in the longitudinal leg 26. The slot 254 extends from a first lateral boundary surface 255 to a second lateral boundary surface 256, i.e., it penetrates all elements 253 of the coil core 25.

[0096] Figure 5 A perspective view showing yet another variant of an embodiment for a coil core 25 is shown. Figure 4 One difference to the variation in is that in this variation there are three grooves 254 , all of which extend from a first lateral boundary surface 255 to a second lateral boundary surface 256 .

[0097] Figure 6 A perspective view of a further variant of the embodiment for the coil core 25 is shown. Figure 4The difference in this variant is that, on the one hand, there are three slots 254, and on the other hand, when viewed in the circumferential direction of stator 2, the three slots 254 extend shorter than the distance between the first and second lateral boundary surfaces. This means that slots 254 do not penetrate all elements 253 of coil core 25, but only a certain number of them. In this embodiment, there are eight elements 253, namely, four elements 253 when viewed from each lateral boundary surface 255, 256.

[0098] Of course, from Figure 2-6 The described variants and embodiments of the coil core 25 can also be combined with one another in any desired manner. All explanations also apply identically or approximately identically to all variants.

[0099] Figure 7 A perspective view of a second embodiment of a magnetic levitation device 1 according to the present invention is shown. In the following description of the second embodiment of the magnetic levitation device 1, only the components from FIG. 1 are explained in more detail. Figure 1 The explanations of the first embodiment also apply in the same way or analogously to the second embodiment. The same reference numerals designate the same features or functionally equivalent features as explained with reference to the first embodiment.

[0100] This embodiment of the magnetic levitation device 1 is similar to the embodiment of the magnetic levitation device 1 from Figure 1 One difference in the embodiment of the present invention is that the back iron 28 is designed differently. The back iron 28 is designed in an annular manner with a metal strip 29 extending from a radially inner opening 291 to a radially outer end 292. The strip 29 forms a plurality of strip windings 293 that lie adjacent to one another with respect to the radial direction R. The longitudinal leg 26 is delimited at a first end 261 by an axial end face 265, against which the back iron 28 rests. The back iron 28 forms a ring whose radial width is equal to the radial width of the end face 265 of the longitudinal leg 26. This means that the radially inner opening 291 is flush with the radially inner inner surface 266 of the longitudinal leg 26 in the axial direction A, and the radially outer end 292 is flush with the radially outer outer surface 267 of the longitudinal leg 26 in the axial direction A.

[0101] Among other things, this has the advantage that there is more space inside the stator 2 which can be used to mount other components therein. In doing so, the stator 2 together with the stator housing 21 can be smaller and more compact, which increases the flexibility of use of the magnetic levitation device 1.

[0102] A further advantage of this arrangement of the back iron 28 arises from the arrangement of the strip windings 293 with the strips 29 wound around the annular core. Due to the fact that the strip windings 293 are arranged perpendicular to the radial direction R, they have an orientation parallel to the course of the magnetic field in the longitudinal legs 26. Therefore, the magnetic field from the longitudinal legs 26 enters the back iron 28 in the axial direction A and therefore parallel to the strip windings 293. This means that the magnetic field does not penetrate any of the strip windings 293 in the radial direction R, thereby avoiding eddy current losses.

[0103] and Figure 1 A further difference of the embodiment in is that the extension of the slots 254 in the longitudinal legs 26 is longer. Depending on the field of application of the magnetic levitation device 1, this may be advantageous in order to achieve a greater reduction in eddy current losses.

[0104] In addition, the rotor 3 in this embodiment is Figure 1 The rotor 3 used here is designed as a so-called four-pole-pair rotor.

[0105] However, it is of course also possible to operate the magnetic levitation device 1 shown in this embodiment with any other rotor 3. Some of these rotors have already been explained in previous sections.

[0106] It goes without saying that all embodiments shown in the description of the figures with their respective features can be combined with one another in any way.

[0107] Furthermore, it is possible that all of the illustrated exemplary embodiments of the coil core 25 can be designed in such a way that the space available for the rotor 3 in the magnetic levitation device 1 is increased. This is achieved by a special outer shape of the coil core 25 .

[0108] During this process, the coil core 25 is divided into an axially lower section and an axially upper section, wherein the lower section and the upper section are arranged adjacent to each other relative to the axial direction A. The transverse legs 27 are arranged in the axially upper section. For each coil core 25, the end face 272 of the transverse leg 27 has a first radial distance from the axially lower section of the associated longitudinal leg 26, and a second radial distance from the axially upper section, wherein the second distance is greater than the first distance. This means that each longitudinal leg 26 is designed such that the axially upper section is radially displaced outward relative to the axially lower section, thereby increasing the space available for the rotor 3 between the end faces 272 without risking direct transmission of magnetic flux between the longitudinal legs 26 and the magnetic effect core 31 of the rotor 3. Due to the fact that the axially upper section is radially offset outward relative to the axially lower section, the distance between the longitudinal leg 26 and the end face 272 (i.e., the second distance) increases in the region of the axially upper section. In doing so, the distance between the magnetic effect core 31 of the rotor and the longitudinal legs 26 , in particular in the region of the axial upper section, is also increased.

[0109] The type of coil core 25 just described is similar to that of European patent application EP 4 084 304 A1. Figure 3 The coil cores are designed specifically for those shown in FIG.

[0110] Figure 8 A schematic cross-sectional view of an embodiment for a stator housing 21 is shown. Figure 1 and Figure 7 In the embodiment shown in FIG, the stator housing 21 is not shown for reasons of better overview. Figure 8 It is intended merely as an illustration to show how the internal packaging of the stator 2 may look like, which is necessary for the operation of the magnetic levitation device 1. For this reason, the other components of the stator 2 are only represented schematically and are to be understood as purely exemplary.

[0111] An embodiment of the stator housing 21 is also possible in which the cup-shaped recess 211 is incorporated into an opening extending centrally in the axial direction A along the center axis of the stator 2 through the entire stator housing 21 .

[0112] During operation of the magnetic levitation device 1 in areas where chemically aggressive substances are used, for example, it is important that the interior of the stator 2 is securely encapsulated and thus protected from these substances. To ensure that the rotor 3 remains usable, the stator housing 21 has a cup-shaped recess 211 into which the rotor 3 can be inserted.

Claims

1. A magnetic levitation device for contactless magnetic levitation of a rotor (3), the rotor (3) comprising a disk-shaped or annular magnetic effect core (31), wherein the magnetic levitation device has a stator (2), the stator (2) comprising a plurality of coil cores (25), wherein each coil core (25) is made of an element (253) in the form of a metal sheet, wherein the elements (253) are stacked in the circumferential direction of the stator (2), wherein each coil core (25) has a first lateral boundary surface (255) and a second lateral boundary surface (256), wherein each coil core (25) comprises a longitudinal leg (26) and a transverse leg (27), wherein the longitudinal leg (26) extends from a first end (261) in an axial direction (A) The stator (2) further comprises a plurality of longitudinal legs (26) and a plurality of longitudinal legs (26) extending upward to a second end portion (262), the transverse leg (27) being arranged at the second end portion (262) of the longitudinal leg and extending in a radial direction perpendicular to the axial direction (A), wherein at least one concentrated winding (61) is provided on each longitudinal leg (26), the at least one concentrated winding (61) being wrapped around the corresponding longitudinal leg (26), wherein the stator (2) further comprises a cup-shaped recess (211), the rotor (3) being insertable into the cup-shaped recess (211), wherein the cup-shaped recess (211) is arranged at an axial end portion of the stator (2), and wherein the transverse leg (27) is arranged around the cup-shaped recess (211), characterized in that At least one of the first lateral boundary surface (255) or the second lateral boundary surface (256) has at least one groove (254).

2. The magnetic levitation device according to claim 1, wherein: The element (253) is made of electrical metal sheet.

3. A magnetic levitation device according to any one of the preceding claims, wherein: The at least one slot (254) extends only in the transverse leg (27).

4. A magnetic levitation device according to any one of the preceding claims, wherein: The at least one slot (254) extends in the transverse leg (27) and in the longitudinal leg (26).

5. The magnetic levitation device according to claim 4, wherein: The at least one groove (254) has a rounding (2541) that redirects the groove (254) from the radial direction (R) to the axial direction (A).

6. A magnetic levitation device according to any one of the preceding claims, wherein: The at least one groove (254) extends from the first lateral boundary surface (255) to the second lateral boundary surface (256).

7. A magnetic levitation device according to any one of the preceding claims, wherein: When viewed in the circumferential direction of the stator (2), the extension of the at least one slot (254) is shorter than the distance of the first lateral boundary surface from the second lateral boundary surface.

8. A magnetic levitation device according to any one of the preceding claims, wherein: Several grooves (254) are provided, which are arranged parallel to each other or at least approximately parallel to each other.

9. A magnetic levitation device according to any one of the preceding claims, wherein: The coil core (25) has a rounded portion (257) at an axially upper end (252), which redirects the coil core from the axial direction (A) to the radial direction (R).

10. A magnetic levitation device according to any one of the preceding claims, wherein: A back iron (28) is arranged at the first end (261) of the longitudinal legs (26), the back iron (28) connecting the first ends (261) of all longitudinal legs (26), wherein the back iron (28) is designed in an annular manner with a metal strip (29) extending from a radially inner start end (291) to a radially outer end (292), wherein the strip (29) forms a plurality of strip windings (293) that are located close to each other with respect to the radial direction (R).

11. A magnetic levitation device according to any one of the preceding claims, wherein: Two concentrated windings (61a, 61b) are provided on each longitudinal leg (26), each of the two concentrated windings (61a, 61b) wrapping around a respective longitudinal leg (26) and arranged adjacent to each other with respect to the axial direction (A).

12. A magnetic levitation device according to any one of the preceding claims, wherein: At least one groove is provided in each case both in the first lateral boundary surface and in the second lateral boundary surface.

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

14. An electromagnetic rotary drive designed as a temple motor, characterized in that The electromagnetic rotary drive comprises a magnetic levitation device (1) according to claim 13, and a rotor (3) having a disk-shaped or annular magnetic effect core (31), wherein the rotor (3) can be inserted into the cup-shaped recess (211), wherein the rotor (3) is designed as the rotor (3) of the electromagnetic rotary drive.

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