Magnetic levitation device

Abstract

To provide a magnetic levitation device for contactless magnetic levitation of a rotor with a disk-shaped or ring-shaped magnetically effective core.SOLUTION: A magnetic levitation device includes a housing 10, a stator 2 and a control device 40. The stator 2 includes a plurality of coil cores 25. Each of the coil cores includes a longitudinal leg 26 extending in an axial direction A and a transverse leg 27 arranged at a second end 262, and the longitudinal leg 26 is surrounded by a concentrated winding 61. The stator 2 includes a cup-shaped recess 211 into which a rotor 3 can be inserted. The control unit 40 includes a circuit board 41, the circuit board having a front side where circuit breakers for controlling the winding are arranged. The housing 10 includes an outer wall 15, a stator housing 101, a control part housing 102, and a separating wall 103. Thermal connecting elements for dissipating heat are provided between the plurality of circuit breakers and a web.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a magnetic levitation device as recited in the preamble of the independent claim.

Background Art

[0002] A magnetic bearing device that magnetically supports a rotor in a non-contact manner has the advantage of not requiring a mechanical bearing for the rotor. The rotor is supported or stabilized by the magnetic force generated by the stator of the magnetic bearing device. Such a magnetic bearing device is particularly suitable for pump transfer, mixing, centrifugation, or stirring devices that convey highly susceptible substances due to the absence of mechanical bearings, such as blood pumps, pump transfer, mixing, centrifugation, or stirring devices in the pharmaceutical or biotechnology industries where strict purity requirements are imposed, or pumps or mixers for slurries, sulfuric acid, phosphoric acid, or other chemicals in the semiconductor industry where abrasive or erosive substances that cause mechanical bearings to fail in a short period are conveyed.

[0003] Such a magnetic bearing device is used in the biotechnology industry, for example, together with a bioreactor, such as a centrifugal pump for conveying fluid into and out of the bioreactor, or a mixing device for mixing fluid within the bioreactor. Such a magnetic bearing device is used not only in the semiconductor industry for conveying highly erosive or abrasive substances but also in, for example, a rotating device for rotating a wafer.

[0004] It is also known to use a magnetic bearing device in a viscometer.

[0005] An advantageous, known design of a magnetic bearing device is a template structure design, and the present invention also relates to a template structure.

[0006] The characteristic features specific to the temple structure are that the stator of the magnetic bearing device comprises a plurality of coil cores, each of the coil cores comprising longitudinal legs extending axially from a first end 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 about which the rotor rotates when the rotor is in an operating state, centered and not tilted with respect to the stator. Each coil core, in addition to the longitudinal legs, also comprises transverse legs arranged at the second end of the longitudinal legs and extending radially, usually inwards, where the radial direction is perpendicular to the axial direction. The transverse legs thus extend substantially at right angles to the longitudinal legs. Each coil core has an L-shape, and the transverse legs form the short legs of the L. The rotor to be supported is, in this case, arranged between the transverse legs.

[0007] The fact that the plurality of longitudinal legs extending axially reminds one of the columns of a temple is the origin of the name of this structure.

[0008] In one design, the stator of the magnetic bearing device comprises, 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 usually circumferentially connected by a back iron which acts to conduct magnetic flux. The rotor to be supported comprises a magnetically effective core, for example a permanent magnet disk or a permanent magnet ring, and is arranged between the radially inner ends of the transverse legs and rotates about the axial direction in an operating state, where the rotor is magnetically supported without contacting the stator.

[0009] In such a magnetic bearing device, it is not always necessary to design the magnetically effective core of the rotor by means of permanent magnets. Designs are also known in which the magnetically effective core of the rotor is designed by a method without permanent magnets, i.e., without permanent magnets. In this case, the magnetically effective core of the rotor is designed, for example, by a ferromagnetic method and is made of, for example, iron, nickel iron, cobalt iron, silicon iron, mu-metal, or another ferromagnetic material.

[0010] Furthermore, a design in which the magnetically effective core of the rotor includes both a ferromagnetic material and a permanent magnetic material is possible. For example, permanent magnets can be arranged or inserted into a ferromagnetic matrix. Such a design is advantageous, for example, when it is desired to reduce the cost of a large rotor by saving permanent magnetic materials.

[0011] The longitudinal legs carry windings and generate the electromagnetic fields necessary to magnetically support the rotor in a non-contact manner. The windings are designed, for example, such that one concentrated winding is wound around each longitudinal leg, i.e., the coil axes of each concentrated winding all extend axially. Here, it is a typical template structure that the coil axes of the concentrated windings extend axially and the concentrated windings are not arranged in the radial plane in which the rotor or the magnetically effective core of the rotor is supported in the operating state.

[0012] It is possible to design one concentrated winding for each longitudinal leg. In other designs, a plurality of, for example, two concentrated windings are provided for each longitudinal leg. It is also possible to provide the windings such that they are wound around two circumferentially adjacent longitudinal legs, and thus both of these two adjacent longitudinal legs are located in the internal space of the concentrated winding.

[0013] A magnetic bearing device generally comprises a control unit that controls a stator winding and supplies electric power, such as a power converter or inverter that supplies a current to be applied to the winding, or a circuit breaker that controls the winding, and includes power electronics. Attempts have been made to arrange the control unit as close as possible to the stator in order to design the magnetic bearing device to be as small as possible and keep the complexity as low as possible. However, in this case, the control unit generates a large amount of heat even in the operating state and it is difficult to dissipate the heat, so a heat problem to be considered arises.

[0014] In the control unit, a significant amount of heat is generated during operation by the power electronics, particularly a circuit breaker that controls the winding, for example. Therefore, when the motor unit and the control unit are arranged close to each other, there is a risk that the heat generated during operation cannot be dissipated sufficiently appropriately, which may cause overheating of the electronic components, particularly significantly shortening the service life of the electronic components.

Summary of the Invention

Problems to be Solved by the Invention

[0015] Therefore, an object of the present invention is to propose a magnetic levitation device that non - contact magnetically levitates a rotor having a ring - shaped or disk - shaped magnetically effective core, which is particularly small in design and in which the control unit is reliably protected against overheating, in view of the above - mentioned state of the art.

Means for Solving the Problems

[0016] The subject matter of the present invention that meets this object is characterized by the configuration of the independent claims.

[0017] Accordingly, according to the present invention, there is proposed a magnetic levitation device for non-contact magnetic levitation of a rotor having a disk-shaped or ring-shaped magnetically effective core, the magnetic levitation device comprising a housing, a stator, and a control device. The stator comprises a plurality of coil cores, each of the coil cores comprising a longitudinal leg extending axially from a first end to a second end, and a transverse leg arranged at the second end of the longitudinal leg and extending in a radial direction perpendicular to the axial direction, at least one concentrated winding being provided on each longitudinal leg, the winding surrounding each longitudinal leg, the stator further comprising a cup-shaped recess into which the rotor can be inserted, the cup-shaped recess being arranged at the axial end of the stator. The control unit comprises a circuit board having a front surface and a back surface, and a circuit breaker for controlling the winding is arranged on the front surface. The housing comprises an outer wall, a stator housing for receiving the stator, a control unit housing for receiving the control unit, and a partition wall separating the stator housing from the control unit housing. At least one web is arranged on the partition wall adjacent to the outer wall, the web protruding into the control unit housing, the back surface of the circuit board being supported on the web, a plurality of circuit breakers being arranged in an area of the circuit board where the back surface of the circuit board is supported on the web, and a thermal connection element for dissipating heat being provided between the plurality of circuit breakers and the web.

[0018] Thanks to this special arrangement combining the circuit breaker and the thermal connection element, it is possible to dissipate particularly efficiently the heat generated by the circuit breaker into the outer wall of the housing via the thermal connection part and at least one web and also via the partition wall, and the heat can then be released from the outer wall to the surroundings, for example by convection. This efficient dissipation of the heat generated by the circuit breaker reliably protects the electronic components of the control unit against overheating. Even if the circuit breaker for controlling the winding is not normally the main heat source of the control unit but is one of the heat sources, reliably dissipating the heat generated by the circuit breaker is an essential aspect for the life and operational safety of the magnetic levitation device.

[0019] Since both the control unit and the stator are arranged within the housing of the magnetic levitation device, the magnetic levitation device according to the present invention features a very compact and space-saving design.

[0020] The thermal connection element is preferably designed as a through-hole plating, also known as a thermal via. A thermal via is typically defined as a hole that extends from the front surface of the circuit board through the circuit board to the back surface of the circuit board. Heat generated by electronic components disposed on the front surface of the circuit board can be dissipated to the back surface of the circuit board via the thermal via and then absorbed by a heat sink.

[0021] The circuit breaker is an electronic component that controls the windings of the stator and supplies energy. The circuit breaker usually includes a transistor, preferably a MOSFET, and a half-bridge or full-bridge for controlling the windings of the stator is realized using the transistor. One or more such half-bridge or full-bridge circuits are usually arranged within the chip housing of the circuit breaker, and a driver can optionally be provided within the chip housing. In this case, the chip housing of the circuit breaker is attached to the front surface of the circuit board using a so-called die attach paddle (DAP). The chip housing of the circuit breaker is provided with a plurality of connection pins, and through the connection pins, the electronic components of the circuit breaker, that is, for example, a transistor, can be electrically connected to conductor tracks or electrical connectors on the circuit board. The chip housing is attached to the circuit board using, for example, an adhesive or a soldering connection.

[0022] In a preferred embodiment of the magnetic levitation device, the outer wall, the partition wall, and the web of the housing are designed as an integral unit. This enables a particularly compact design and efficient heat dissipation through the housing.

[0023] Each circuit breaker is arranged on a separate mounting surface, each mounting surface being connected to the back surface of the circuit board via a plurality of thermal connection elements, and each thermal connection element preferably extending from the front surface to the back surface of the circuit board. Such mounting surfaces on the front surface of the circuit board are preferably designed as cooling surfaces, in particular metal cooling surfaces, and each of the mounting surfaces is preferably thermally connected to the back surface of the circuit board via a plurality of thermal vias.

[0024] Providing additional thermal connection elements, each of the additional thermal connection elements extending from the front surface to the back surface of the circuit board and each of the additional thermal connection elements being arranged outside a separate mounting surface, is a preferred measure. The thermal connection elements thus include elements that are not arranged under the mounting surface of the circuit breaker but are arranged in other areas of the circuit board. In this way, heat can also be dissipated, in particular, from the area on the front surface of the circuit board where the circuit breaker is not arranged.

[0025] Providing contact pads on the back surface of the circuit board for each mounting surface, with the contact pads thermally coupling all the thermal connection elements belonging to this mounting surface to each other, is an even more preferred measure. This means that all the thermal connection elements belonging to the same mounting surface terminate at the contact pads on the back surface of the circuit board, whereby the contact pads thermally couple all these thermal connection elements on the back surface of the circuit board to each other. Since heat is transmitted to the housing over a wide area by the contact pads, the use of such contact pads can further improve the thermal connection to the housing of the magnetic levitation device.

[0026] Furthermore, arranging a heat conduction layer between the web and the back surface of the circuit board, with the heat conduction layer enabling heat to be transmitted from the circuit board to the housing, is a preferred measure.

[0027] The heat conduction layer is preferably designed as a film attached to the back surface of the circuit board. The film is made of a heat-conductive material. This film can be mounted or soldered to the back surface of the circuit board. The heat conduction layer can transfer heat to the housing over a wide area, thereby reducing the thermal transition resistance.

[0028] Each heat conduction layer designed as a film is preferably made of a material with high thermal conductivity and is easily deformable, especially ductile, so that the film can also compensate for small unevenness and mechanical tolerances.

[0029] The heat conduction layer is particularly preferably made of a metallic material such as copper or silver. Each heat conduction layer is designed, for example, as a copper film. The copper film has the advantage of being easy to solder. To further improve the solderability, the copper film can also be coated with a noble metal (e.g., gold).

[0030] Another possibility is to use a lacquer for the heat conduction layer. Here, a lacquer with a high content of metal particles is preferred. In this case, such a lacquer is applied to the contact surface to form the heat conduction layer. The heat conduction layer thus obtained is also relatively easy to deform and also enables a very good thermal connection.

[0031] According to a preferred embodiment, the control unit housing of the housing is designed such that the internal space has a substantially rectangular or square cross-sectional area perpendicular to the axial direction. Thereby, the control unit housing is preferably particularly suitable for receiving a circuit board designed in a rectangular or square shape of the control device, which is preferred. The rectangular or square design of the circuit board is much easier, for example, than a round design, especially from the perspective of manufacturing.

[0032] Furthermore, the stator housing of the housing is preferably designed such that the internal space has a substantially round cross-sectional area perpendicular to the axial direction A. Thereby, the stator housing is preferably particularly suitable for receiving the coil core of the stator arranged preferably on a circular line, which is preferred.

[0033] In a preferred embodiment, the housing cover is arranged at one axial end of the magnetic levitation device, and the housing cover closes the control unit housing. It is particularly preferred that the housing cover is designed to hermetically seal the control unit housing.

[0034] Furthermore, it is preferable that the stator includes a receiving container that forms one axial end of the stator, and the receiving container includes a cup-shaped recess. In this case, the rotor to be levitated can be inserted into the cup-shaped recess of the receiving container.

[0035] The partition wall preferably includes an inner cup designed substantially cylindrically, and the inner cup is arranged radially inside the winding in the inner space surrounded by the winding. The inner cup is advantageous for better dissipating the heat generated by the stator in the operating state, for example, the heat generated by copper loss and iron loss.

[0036] The housing preferably includes a stator housing and a control unit housing that are arranged adjacent to each other in the axial direction. The stator housing is designed to receive a coil core with concentrated windings arranged thereon, and the control unit housing is designed to receive a control unit that controls the windings to generate an electromagnetic field and supplies electrical energy to the windings.

[0037] Preferably, the housing is designed such that a coil core with concentrated windings can be inserted into the stator housing in a first mounting direction in the axial direction, and a control unit can be inserted into the control unit housing in a second mounting direction, where the first mounting direction is opposite to the second mounting direction. The housing preferably has two separated areas, one of which forms the stator housing and the other forms the control unit housing. These two areas are separated from each other by a partition wall. The partition wall has, for example, a passage for electrical connection. The housing is preferably designed integrally in the circumferential direction.

[0038] According to a particularly preferred embodiment, the stator is designed to generate torque that can magnetically drive the rotor to rotate about the axial direction without contact.

[0039] Further advantageous measures and embodiments of the present invention are apparent from the dependent claims.

[0040] Hereinafter, the present invention will be described in more detail with reference to embodiments and the drawings.

Brief Description of the Drawings

[0041]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Modes for Carrying Out the Invention

[0042] Figure 1 shows a cross-sectional view of an embodiment of a magnetic levitation device according to the present invention, which is denoted by reference numeral 1 as a whole. The magnetic levitation device 1 is designed to magnetically levitate a rotor 3 having a disk-shaped or ring-shaped magnetically effective core 31 in a non-contact manner.

[0043] For better understanding, Figure 2 also shows a perspective view of the embodiment of Figure 1 in the form of an exploded perspective view, and the rotor 3 is not shown in Figure 2. The magnetic levitation device 1 is designed according to a template structure and includes a stator 2. The stator 2 includes a plurality of coil cores 25, here six coil cores 25. Each coil core includes a longitudinal leg 26 extending from a first end 261 to a second end 262 in the axial direction A, and a transverse leg 27 disposed perpendicular to the longitudinal leg 26 and extending in the radial direction perpendicular to the axial direction A. Each transverse leg 27 is radially bounded by an end face 271 and forms a pole of the corresponding coil core 25.

[0044] At least one, in this embodiment one concentrated winding 61, is provided on each longitudinal leg 26 and surrounds each longitudinal leg 26.

[0045] The magnetic levitation device 1 includes a housing 10 in which the coil cores 25 are disposed.

[0046] Figures 3 and 4 show further views of the stator 2 of the embodiment of the magnetic levitation device 1 for better understanding, and the housing 10 is not shown. Figure 3 shows a perspective view of the stator 2 and the holding device 9 of the coil core 25. Figure 3 further shows a back iron 22, which connects all the first ends 261 of the longitudinal legs 26, that is, the lower ends 261 in the illustration (Figure 1), to each other and acts to conduct magnetic flux. The back iron 22 is preferably designed in a ring shape. Figure 4 shows an exploded perspective view of the coil core 25 in which the concentrated winding 61 is disposed and the holding device 9.

[0047] The housing 10 is preferably made of a metallic material, such as aluminum or stainless steel. To further enhance chemical resistance, the housing 10 can be provided with a coating, preferably a plastic coating made of a highly chemically resistant plastic. Examples of such plastics include PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy polymer), ECTFE (ethylene chlorotrifluoroethylene), ETFE (ethylene tetrafluoroethylene), epoxy resin (polyepoxy), PPA (polyphthalamide), and PE (polyethylene). The housing 10 can also be made of titanium or chrome steel depending on the intended application.

[0048] The stator 2 further includes a receiving container 21 having a cup-shaped recess 211 (see also FIG. 5) into which the rotor 3 to be levitated can be inserted (see FIG. 1). The receiving container 21 forms one of the two axial ends of the stator 2 or the magnetic levitation device 1, which, according to the illustration in FIG. 1, is the upper axial end of the stator 2. A housing cover 11 closing the housing 10 is arranged at the other axial end of the magnetic levitation device 1.

[0049] The receiving container 21 is firmly connected to the housing 10, for example, by a form-locking connection and / or by using an elastic seal 201. The receiving container 21 is preferably connected to the housing 10 in a gas-tight manner. The housing cover 11 is firmly connected to the housing 10, for example, by using screws 111 (FIG. 1), and optionally, a sealing element 105 is arranged between the housing cover 11 and the housing 10. The sealing element 105 can be designed, in particular, as a flat seal. The housing cover 11 is preferably connected to the housing 10 in a gas-tight manner.

[0050] The housing 10 is particularly preferably integrally formed with the storage container 21 and the housing cover 11 to form a hermetically sealed housing in which other components of the stator 2 are hermetically sealed. It is preferable that the housing 10 is filled with a potting compound having a high thermal conductivity, for example, an epoxy resin, and as a result, the components arranged inside the housing 10 are surrounded by the potting compound. In this way, the overall thermal resistance is reduced and vibration is attenuated.

[0051] The housing cover 11 is preferably made of plastic. Particularly in applications in an environment with high chemical erosiveness, chemical-resistant plastics such as polypropylene are preferable.

[0052] The lateral legs 27 of the coil core 25 are arranged in the storage container 21 such that the end face 271 of the lateral legs 27 is arranged around the periphery of the cup-shaped recess 211.

[0053] The coil cores 25 of the stator 2 are arranged at equal intervals on a circular line. As a result, when the rotor 3 is inserted into the cup-shaped recess 211, the end face 271 surrounds the magnetically effective core 31 of the rotor 3. One concentrated winding 61 is provided on each longitudinal leg 26 and surrounds the longitudinal leg 26.

[0054] In other embodiments, a plurality of concentrated windings can also be arranged on the longitudinal legs 26. For example, there is an embodiment in which two concentrated windings are provided on each of the longitudinal legs 26. The two concentrated windings each surround the respective longitudinal leg 26, and the two windings arranged on the same longitudinal leg 26 are arranged adjacent to each other in the axial direction A.

[0055] The concentrated winding 61 acts to generate an electromagnetic field that can magnetically levitate the rotor 3 without contact within the cup-shaped recess 211 of the storage container 21.

[0056] Furthermore, a control unit 40 is provided that controls the winding 61 and supplies electrical energy to the winding. The control unit 40 particularly includes power electronics that supply the necessary current to the winding 61. The control unit 40 is shown in FIGS. 1 and 2. The control unit 40 is particularly preferably arranged inside the housing 10 below the first end 261 of the longitudinal leg 26 of the coil core 25, for example according to the illustration (FIG. 1). The control unit 40 is optionally also surrounded by a thermal potting compound or is coupled to the housing 10 and the back iron 22 and / or the coil core 25 of the stator 2. The control unit 40 includes a circuit board 41 on which various electronic components 42 are arranged.

[0057] The housing 10 preferably has two areas that are separated from each other and arranged adjacent to each other in the axial direction A, as can be particularly recognized in FIGS. 1 and 2. One of them forms the stator housing 101, and the other forms the control unit housing 102. The stator housing 101 of the housing 10 is designed to receive the coil core 25 in which the winding 61 is arranged, and the control unit housing 102 is designed to receive the control unit 40. The stator housing 101 and the control unit housing 102 are separated from each other by a partition wall 103, and the partition wall 103 is provided with a lead-through or an opening 104 (see FIG. 6 for example), and a connection line, for example an electrical connection part, can pass from the control unit housing 102 into the stator housing 101 through the lead-through or the opening 104.

[0058] According to a preferred measure, the separating wall 103 comprises an inner cup 13 which is designed substantially cylindrically and which is arranged radially inside the winding 61 in the inner space surrounded by the winding 61. The inner cup 13 is connected to the outer wall 15 of the housing 10 via the flange-like projection 14 of the separating wall 103. The outer wall 15 forms the radially outer boundary of the housing 10. It is particularly preferred that the separating wall 103 with the inner cup 13 and the flange-like projection 14 is an integral part of the housing 10. The outer wall 15 and the separating wall 103 are preferably designed integrally throughout to form an integral housing 10.

[0059] The separating wall 103 with the inner cup 13 and the flange-like projection 14 separates the area of the housing 10 forming the stator housing 101 from the area forming the control unit housing 102.

[0060] The inner cup 13 of the separating wall 103 connected to the flange-like projection 14 extends in the axial direction A from the radially inner edge of the flange-like projection 14 and is arranged radially inside the winding 61 and the back iron 22 in the inner space surrounded by the winding 61. The inner cup 13 is arranged radially adjacent to the longitudinal leg 26 of the coil core 25 or the winding 61 arranged on the longitudinal leg, so that the inner cup 13 can absorb and dissipate particularly well the heat generated by the winding 61 and the coil core 25. The inner cup 13 extends in the axial direction A substantially up to the cup-shaped recess 211 of the receiving container 21.

[0061] The stator housing 101 of the housing 10 is designed such that the internal space has a cross-sectional area perpendicular to the axial direction A that is substantially circular or ring-shaped, as can be particularly recognized in FIG. 2. Thereby, the stator housing 101 can preferably receive the ring-shaped back iron 22 particularly well together with the coil core 25 arranged around the back iron 22. The control unit housing 102 of the housing 10 is designed such that the internal space has a cross-sectional area perpendicular to the axial direction A that is substantially rectangular or square. Thereby, the control unit housing 102 is preferably particularly suitable for receiving the circuit board 41 of the control device 40 designed to be rectangular or square, which is preferable. The rectangular or square design of the circuit board 41 is much simpler, particularly with regard to manufacturing, for example, than a round design.

[0062] According to this embodiment of the stator housing 101 and the control unit housing 102, since the axial end of the stator 2 where the housing container 21 closes the housing 10 has a substantially round cross-section, the housing container 21 has a round or circular ring-shaped design. In contrast, since the axial end of the stator 2 where the housing cover 11 closes the housing 10 has a substantially rectangular or square cross-section, the housing cover 11 has a rectangular or square design.

[0063] Some components of the control unit 40 having exemplary features are shown in FIG. 1. The control unit 40 includes, for example, an electronic component 42 and a circuit board 41 provided with power electronics for controlling, for example, the winding 61. This will be described in more detail below. The circuit board 41 can further accommodate, for example, an evaluation electronic circuit for evaluating signals from sensors, for example magnetic field sensors, or can function as a communication interface. The circuit board 41 is preferably designed as an electronic print or PCB (printed circuit board). Further, a connection cable 45 is provided, and the connection cable is connected to the circuit board 41 via a cable connection part (not shown) or a plug. The connection cable 45 is drawn out from the housing 10 and acts, for example, to supply power to the magnetic levitation device 1. The connection cable 45 is drawn out from the housing 10 using a cable bushing 47 with a sealed design. The cable bushing 47 is preferably designed in a hermetically sealed state.

[0064] The circuit board 41 of the control device 40 is connected to the winding 61 via a connection line (not shown), for example a cable, in order to control the winding and supply energy to the winding. For this purpose, a feed-through or opening 104 (FIG. 8) through which the connection line passes is provided in the partition wall 103. Such a feed-through can be arranged, for example, in a flange-like projection 14 or an internal cup 13.

[0065] The circuit board 41 is preferably arranged in the flange-like projection 14 as will be described in more detail below. In this way, the heat generated in the control unit 40 can be dissipated particularly efficiently via the housing 10.

[0066] The internal space of the internal cup 13, that is, the space surrounded by the internal cup 13, can be used for further electronic components, electronic substrates, or plugs or connection parts. These are not shown in FIG. 1 for better overview.

[0067] According to a particularly preferred embodiment, the stator 2 is designed such that, in addition to magnetically levitating the rotor 3 in a non-contact manner, it can also apply torque to the rotor 3 or the magnetically effective core 31 of the rotor 3, driving the rotor 3 to rotate about a desired axis of rotation. Here, the desired axis of rotation refers to the axis about which the rotor 3 rotates when the rotor 3 is in an operating state, centered and not tilted with respect to the stator 2, as shown in FIG. 1. This desired axis of rotation extends in the axial direction A. That is, in this preferred embodiment, the rotor 3 disposed within the housing 21 of the stator 2 can be driven to rotate about the axial direction A. The desired axis of rotation generally coincides with the central axis of the stator 2 extending in the axial direction A.

[0068] Thus, in this embodiment, the concentrated winding 61 generates an electromagnetic rotating field that can magnetically levitate the rotor 3 without contacting the stator 2 and drive the rotor 3 to rotate without contacting about the axial direction A.

[0069] It should be understood that the number of the six coil-cores 25 is merely an example for preference. Of course, embodiments where the stator 2 has less than six, for example, five, four, or three coil-cores 25, or embodiments where the stator 2 has more than six, for example, seven, eight, or nine coil-cores, or even more coil-cores 25 are also possible.

[0070] The rotor 3 comprises a magnetically effective core 31 designed in a ring shape or a disk shape. According to the illustration in FIG. 1, the magnetically effective core 31 is designed as a ring and defines a magnetic center plane. As an alternative, the magnetically effective core 31 can also be designed as a disk. Usually, in the case of a disk-shaped or ring-shaped magnetically effective core 31, the magnetic center plane is the geometric center plane of the magnetically effective core 31 of the rotor 3 that is positioned perpendicular to the axial direction A. In the operating state, the magnetically effective core 31 floats in a radial plane E perpendicular to the axial direction A. In FIG. 1, the radial plane is indicated by a line E perpendicular to the axial direction A. The radial plane E is thus a plane perpendicular to the axial direction A and containing the line E.

[0071] The radial plane E is the plane in which the magnetically effective core 31 of the rotor 3 actively magnetically levitates between the end faces 271 of the stator 2 in the operating state. When the rotor 3 is not tilted and not offset in the axial direction A, the magnetic center plane is located in the radial plane E. The radial plane E defines the x-y plane of a Cartesian coordinate system in which the z-axis extends in the axial direction A.

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

[0073] For the purpose of sufficient understanding of the present invention, only the magnetically effective core 31 is shown in the rotor 3 in the drawing of FIG. 1. It should be understood that the rotor 3 can of course also comprise further components such as a jacket or an encapsulation container, which are preferably made of plastic, metal, alloy, or ceramic or ceramic material. The rotor 3 can further also comprise vanes for mixing, stirring, or pumping a fluid or other constituent substances.

[0074] When the rotor 3 is inserted into the cup-shaped recess 211 of the receiving container 21, the rotor 3, and in particular the magnetically effective core 31 of the rotor 3, is surrounded by the end faces 271 of the lateral legs 27 of the coil core 25 of the stator 2, which are arranged radially outward. The lateral legs 27 thus form a plurality of stator poles, in this case six stator poles. The lateral legs 27 are arranged at the upper end of the longitudinal legs 26 and in the radial plane E. Each lateral leg 27 extends radially towards the rotor 3.

[0075] When the magnetically effective core 31 of the rotor 3 is in the desired position during operation, the magnetically effective core 31 is centered between the end faces 271 of the lateral legs 27 and thus the lateral legs 27 arranged in the radial plane E are also located in the magnetic center plane. The concentrated winding 61 is, according to the illustration, arranged below the radial plane E and aligned such that the coil axis of the concentrated winding extends in the axial direction A.

[0076] All first ends 261 of the longitudinal legs 26, i.e., the lower ends 261 according to the illustration (FIG. 1), are connected to one another by the back iron 22 (see also FIG. 3). The back iron 22 is preferably designed in a ring shape. In this case, an embodiment is possible in which the back iron 22 extends radially inward along all first ends 261 of the longitudinal legs 26 (see, for example, FIG. 1).

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

[0078] Such an electromagnetic rotating field is generated by this concentrated winding 61 in the operating state, and a lateral force that can be arbitrarily adjusted in the radial direction can be applied to the rotor 3 by the electromagnetic rotating field. Therefore, the radial position of the rotor 3, that is, the position of the rotor 3 in the radial plane E perpendicular to the axial direction A, can be actively controlled or adjusted. Optionally, such an electromagnetic rotating field further generates torque on the rotor 3.

[0079] The "magnetically effective core 31" of the rotor 3 refers to the region of the rotor 3 that magnetically interacts with the stator 2 to generate a magnetic levitation force and, optionally, a torque.

[0080] As already mentioned, in this embodiment, the magnetically effective core 31 is designed in a ring shape. The magnetically effective core 31 is further designed in a permanent magnet type. For this purpose, the magnetically effective core 31 can include at least one permanent magnet, but can also include a plurality of permanent magnets, or, as in the embodiment described here, can be entirely composed of a permanent magnetic material such that the magnetically effective core 31 becomes a permanent magnet. The magnetically effective core 31 is magnetized in the radial direction, for example.

[0081] Embodiments are also possible in which the magnetically effective core 31 has no permanent magnets, that is, is designed without permanent magnets. In this case, the rotor 3 is designed as a reluctance rotor, for example. The magnetically effective core 31 of the rotor 3 is made of a soft magnetic material in this case, for example. Suitable soft magnetic materials for the magnetically effective core 31 are, for example, ferromagnetic materials or ferrimagnetic materials, that is, in particular iron, nickel iron, cobalt iron, silicon iron, and mu-metal.

[0082] Furthermore, embodiments are possible in which the magnetically effective core 31 of the rotor 3 includes both a ferromagnetic material and a permanent magnetic material. For example, a permanent magnet can be disposed or inserted into a ferromagnetic matrix. Such an embodiment is advantageous, for example, when it is desired to reduce the cost of a large rotor by saving permanent magnetic material.

[0083] Embodiments are also possible in which the rotor is designed according to the principle of a squirrel-cage rotor.

[0084] Both the ring-shaped back-iron 22 and the coil-core 25 of the stator 2 are made of a soft magnetic material in order to function as a magnetic flux conducting element for conducting magnetic flux.

[0085] Suitable soft magnetic materials for the coil-core 25 and the back-iron 22 are, for example, ferromagnetic or ferrimagnetic materials, i.e., in particular iron, nickel iron, cobalt iron, silicon iron, or mu-metal. In the case of the stator 2, it is preferably designed such that the coil-core 25 and the back-iron 22 are made of sheet metal, i.e., designed as a sheet laminate of the stator consisting of a plurality of stacked thin sheet metal elements.

[0086] The coil-core 25 and the back-iron 22 can also be made of pressed and subsequently sintered grains of the aforementioned materials. The metal grains are preferably embedded in a plastic matrix such that the metal grains are at least partially insulated from each other, thereby minimizing eddy current losses. Thus, soft magnetic composite materials consisting of electrically insulated and compressed metal particles are also suitable for the stator. In particular, such soft magnetic composite materials, also referred to as SMC (Soft Magnetic Composites), can be composed of iron powder grains coated with an electrical insulation layer. This SMC is then shaped into the desired shape in a powder metallurgy process.

[0087] The magnetically effective core 31 of the rotor 3 interacts with the stator 2 such that during operation of the magnetic levitation device 1, the rotor 3 can be magnetically levitated without contacting the stator 2, and more preferably can rotate magnetically about the axial direction A without contacting. In this case, it is particularly advantageous that the same winding 61 that provides magnetic levitation of the rotor 3 also acts to generate torque on the rotor 3. In this case, it is preferable that the three degrees of freedom of the rotor 3, namely the position and rotation in the radial plane E of the rotor, can be actively adjusted. The magnetically effective core 31 of the rotor 3 is passively magnetically stabilized by magnetic reluctance with respect to the axial offset of the core 31 from the radial plane E in the axial direction A. That is, the axial offset of the core cannot be controlled. The magnetically effective core 31 of the rotor 3 is also passively magnetically stabilized with respect to the remaining two degrees of freedom, namely the inclination with respect to the radial plane E perpendicular to the desired axis of rotation. The rotor 3 is thus passively magnetically levitated or passively magnetically stabilized in the axial direction A and against inclination (a total of three degrees of freedom) by the interaction between the magnetically effective core 31 and the coil core 25, and is actively magnetically levitated in the radial plane (two degrees of freedom).

[0088] Active magnetic levitation, as is generally the case, can also be referred to as magnetic levitation that can be actively controlled or adjusted by an electromagnetic field generated, for example, by the concentrated winding 61, within the framework of this application. Passive magnetic levitation or passive magnetic stabilization cannot be controlled or adjusted. Passive magnetic levitation or passive magnetic stabilization is based on magnetic reluctance that returns the rotor 3 to the desired position when the rotor 3 is deflected from the desired position, for example, when the rotor is displaced or deflected in the axial direction A, or when the rotor is inclined.

[0089] In the magnetic levitation device 1, the generation of magnetic levitation and optionally torque acting on the rotor is realized by an electromagnetic rotating field, in contrast to conventional magnetic bearings. In order to generate a combination of the magnetic levitation force and the torque that rotates the rotor 3 about the axial direction A, on the one hand, as shown in FIG. 1, it is possible to arrange one concentrated winding 61 on each longitudinal leg 26.

[0090] On the other hand, an embodiment in which two different winding systems are provided to generate a combination of magnetic levitation force and torque for rotating the rotor 3 is also possible. For this purpose, for example, two concentrated windings are each arranged on the longitudinal leg portions, and the two concentrated windings are arranged adjacent to each other in the axial direction A. One of these two windings belongs to the first winding system of the two winding systems, and the other belongs to the second winding system of the two winding systems.

[0091] In the embodiment shown in FIG. 1, in which each coil core 25 is provided with one concentrated winding 61, both the current value required for levitation and the current value required for generating torque are determined, for example, by the control unit 40 and added or superimposed by calculation using, for example, software. Then, the total current obtained as a result is applied to each concentrated winding 61.

[0092] The back iron 22 is shown separated from the coil core 25 in FIG. 3 for better understanding. The back iron 22 is designed substantially in a ring shape and, in the assembled state, extends radially inward along the first end portion 261 of the longitudinal leg portion 26 (see also FIG. 1). The back iron 22 is preferably designed as sheet metal. In the sheet metal embodiment, the back iron 22 is made up of a plurality of thin elements stacked parallel to each other in the axial direction. In this case, all the elements are substantially ring-shaped and are identically designed so that they all have the same thickness.

[0093] The back iron 22 includes a plurality of flat portions 222 designed in a planar manner, i.e., without curvature, on its radially outer peripheral surface. In the state where the stator 2 is assembled, preferably, one of the first ends 261 of the longitudinal legs 26 having a rectangular contour abuts against each of these flat portions 222. Due to the planar design of the flat portions 222, a wide contact surface is ensured between the back iron 22 and the longitudinal legs 26 of the coil core 25. As a result, magnetic flux is conducted particularly well or the magnetic resistance becomes very small at the transition portion between the back iron 22 and the longitudinal legs 26. The flat portions can also be arranged in separate segments 225, and the separate segments 225 are arranged in the grooves of the back iron 22. The grooves are dimensioned such that the separate segments 225 are flush with the remaining part of the back iron 22.

[0094] The number of the flat portions 222 is preferably the same as the number of the coil cores 25, i.e., six flat portions 222 are provided here, and the flat portions are preferably evenly distributed along the outer periphery of the back iron 22.

[0095] The back iron 22 can further be provided with one or more ventilation holes or ventilation recesses 223 that extend completely through the back iron 22 in the axial direction A. For example, when the housing 20 is filled with a thermally conductive potting material, air can be released through the ventilation recesses 223.

[0096] The magnetic levitation device 1 preferably includes a plurality of magnetic field sensors (not shown) arranged around the cup-shaped recess 211 in the state where the magnetic levitation device 1 is assembled to determine the current position of the rotor 3 in the cup-shaped recess 211. The magnetic field sensor is a sensor capable of measuring a magnetic field. Using the magnetic field sensor, the current position of the rotor 3 in the cup-shaped recess 211 of the housing container 21 or in the radial plane E can be determined by a known method.

[0097] The magnetic field sensors are arranged on the sensor substrate 7 and are signal-connected to the sensor substrate via electrical connection parts, whereby all the magnetic field sensors can be controlled via the sensor substrate 7, and the signals measured by the magnetic field sensors are preferably received and processed by the sensor substrate 7 or can be transmitted, for example, to the control device 40.

[0098] The sensor substrate 7 is arranged in the axial direction A between one winding 61 and the other transverse leg 27. The holding device 9 is designed to receive the sensor substrate 7.

[0099] The sensor substrate 7 further comprises an electrical connection element 76 for connecting the sensor substrate 7 to the control device 40, whereby the control device 40 and the sensor substrate 7 can exchange voltage or current via the electrical connection element 76. The electrical connection element 76 is preferably designed as a flexible printed circuit. The electrical connection element 76 can of course also be designed in another way, for example as a cable, a cable bundle or a flat ribbon cable.

[0100] FIG. 5 shows a cross-section of the housing 21 of the stator 2 of an embodiment of the magnetic levitation device 1, the cross-section being made in the axial direction A.

[0101] The receiving container 21 having the cup-shaped recess 211 is preferably designed integrally. The cup-shaped recess has an outer diameter DA dimensioned such that the rotor 3 to be floated can be inserted into the cup-shaped recess 211. The receiving container 21 is preferably made of plastic, and particularly preferably made of a plastic that can be processed by injection molding. The receiving container 21 is thus preferably designed as an injection molded part. Plastics suitable for manufacturing the receiving container 21 are, for example, acrylonitrile butadiene styrene (ABS), polyamide (nylon, PA), polypropylene (PP), polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane (PFA), polyvinyl chloride (PVC), polybutylene terephthalate (PBT), polyimide (PI), polyether ketone, polysuccinimide (PSI), polyphthalamide (PPA), or polyether ether ketone (PEEK).

[0102] The receiving container 21 includes a cup-shaped recess 211 into which the rotor 3 can be inserted, and a radially outer edge 212 that surrounds the axial edge area 92 of the holding device 9 in the assembled state.

[0103] The holding device 9 is designed substantially in a plate shape and a ring shape, and includes a plurality of notches 91 (FIG. 4) for receiving the lateral legs 27 of the coil core 25. One notch 91 is provided for each lateral leg 27 such that the number of notches 91 is equal to the number of coil cores 25. The holding device 9 is inserted into the receiving container 21 (see FIG. 1) and extends from the bottom of the receiving container 21 in the axial direction A to the lower edge as shown in the drawing (FIG. 1) above the winding 61 in the axial direction A according to the drawing.

[0104] The holding device 9 is designed in a ring shape so that it can be arranged around the cup-shaped recess 211 of the receiving container 21. That is, the cup-shaped recess 211 is surrounded by the holding device 9 on the radially outer side.

[0105] The holding device 9 is preferably made of plastic, and particularly preferably made of a plastic that can be processed by injection molding. The holding device 9 is thus preferably designed as an injection molded part. Plastics suitable for the manufacture of the holding device 9 are, for example, acrylonitrile butadiene styrene (ABS), polyamide (nylon, PA), polypropylene (PP), or fiber-reinforced polypropylene.

[0106] The holding device 9 functions as a holder for the sensor substrate 7 provided with the magnetic field sensor and also as a guide and holder for the coil core 25.

[0107] FIG. 6 shows a perspective view of the control unit housing 102 and the circuit board 41 of the control device 40. The circuit board 41 has a front surface 411 and a back surface 412. The electronic components 42 necessary for controlling the winding 61 and supplying electrical energy to the winding 61 are arranged on the front surface of the circuit board 41 of the control unit 40. The electronic components are in particular a circuit breaker 420 (see also FIG. 10) for controlling the winding 61, by means of which the current supplied to the winding 61 is switched. The electronic components 42 further include adjustment and control components for controlling non-contact magnetic levitation and optionally non-contact magnetic drive, but since they are known, they will not be described in more detail here.

[0108] The circuit breaker 420 usually comprises a transistor, preferably a MOSFET, and a half-bridge or full-bridge for controlling the winding 61 of the stator 2 is realized using the transistor. One or more such half-bridge or full-bridge circuits are usually arranged within the chip housing 424 (FIG. 7) of the circuit breaker 420, and a driver can optionally be provided within the chip housing 424. The chip housing 424 of the circuit breaker 420 is in this case attached to the front face 411 of the circuit board 41 using a so-called die-attach paddle (DAP). The chip housing 424 of the circuit breaker 420 is provided with a plurality of connection pins (not shown in detail), and via the connection pins, the electronic components of the circuit breaker 420, i.e., for example, the transistor, can be electrically connected to conductor tracks or electrical connectors on the circuit board 41. The chip housing 424 of the circuit breaker 420 is attached to the circuit board 41, for example, using an adhesive or by soldering connection.

[0109] FIG. 8 shows a plan view of the control unit housing 102 for better understanding. FIG. 9 shows a plan view of the back face 412 of the circuit board 41, and FIG. 10 shows a plan view of the front face 411 of the circuit board 41.

[0110] As can be clearly recognized particularly in FIGS. 6 and 8, a plurality of webs 8 adjacent to the outer wall 15 of the housing 10 are provided on the separating wall 103 defining the boundary of the control unit housing 102, and the webs project into the control unit housing 102. The webs 8 are preferably an integral part of the separating wall 103 and the outer wall 15. It is particularly preferred that the housing 10, i.e., in particular the outer wall 15, the separating wall 103, and the webs 8, form a structural unit made of a metallic material, for example, aluminum or stainless steel.

[0111] The web 8 is disposed at a location where the partition wall 103 is adjacent to the outer wall 15. The web 8 acts to support the circuit board 41. The circuit board 41 is attached to the web 8 using a plurality of screws such that the back surface 412 of the circuit board 41 is disposed on the web 8 and reaches and engages with the screw-cut holes 81 disposed in the web 8 through the screw holes 82 (FIG. 9) of the circuit board 41.

[0112] The web 8 thus functions as a support for supporting the back surface 412 of the circuit board 41. It should be understood that "supporting" or "abutting" as used herein means that the web 8 supports the circuit board 41, but this does not mean that the back surface 412 of the circuit board 41 must be in direct physical contact with the web 8. Of course, embodiments where the back surface 412 is in direct physical contact with the web 8 are also possible. However, since, for example, a contact pad 87 or a heat conduction layer 88 can be disposed between the back surface 412 of the circuit board 41 and the web 8, embodiments are also possible where the web 8 is only partially in direct physical contact with the back surface of the circuit board 41 or not in direct physical contact at all. This is shown, for example, in the embodiments of FIGS. 10 and 11. The area where the back surface 412 of the circuit board 41 is supported by the web 8 thus refers to the area that overlaps the web 8 when viewed in the axial direction A, and such areas can be in direct physical contact with the web 8 either wholly or partially, but do not necessarily have to be in direct physical contact.

[0113] A plurality of circuit breakers 420 are disposed on the front surface 411 of the circuit board 41 in the area where the back surface 412 of the circuit board 41 abuts against the web 8, as can be particularly recognized in FIG. 10. Preferably, all of the circuit breakers 420 are disposed in the area of the circuit board 41 where the back surface 412 of the circuit board 41 abuts against the web 8. Further, a heat connection element 85 (FIG. 7) is provided for each circuit breaker 420, and the heat connection element thermally connects the circuit breaker 420 to the web 8 that abuts against the area of the circuit board 41 where each circuit breaker 420 is disposed.

[0114] Each thermal connection element 85 is preferably designed as a through-hole plating. The term thermal via is also commonly used for such through-hole plating. The through-hole plating forms a thermal bridge extending from the front surface 411 of the circuit board 41 to the back surface 412 of the circuit board 41.

[0115] Preferably, a plurality of thermal connection elements 85 are provided for each circuit breaker 420. This is shown in the schematic diagram of FIG. 7. FIG. 7 shows, in the right illustration, the details of the back surface 412 of the circuit board 41, that is, the area of the back surface 412 where one of the circuit breakers 420 is arranged on the front surface 411. A total of 16 thermal connection elements 85 are provided, each of the thermal connection elements being designed as a through-hole plating and thermally connecting the circuit breaker 420 to the back surface 412 of the circuit board 41 and thus to the web 8 with which this area of the circuit board 41 abuts. The 16 thermal connection elements 85 are arranged in 4 columns with 4 thermal connection elements 85 in each column. It should be understood that the number of thermal connection elements 85 per circuit breaker being 16 is an example. Of course, the number of thermal connection elements 85 per circuit breaker 420 can be more or less than 16.

[0116] The left illustration of FIG. 7 schematically shows a cross-section through the circuit board 41 with one of the circuit breakers 420 arranged on the front surface 411 of the circuit board 41. Individual mounting surfaces 421 are provided on the front surface 411 of the circuit board 41 for each circuit breaker 420, and it is preferred that each circuit breaker 420 is attached to the mounting surface, for example, by a soldering connection. The mounting surface 421 is preferably made of a material having good thermal conductivity, such as a metal material.

[0117] The circuit breaker 420 usually includes a transistor, preferably a MOSFET, and a half-bridge or full-bridge for controlling the winding 61 of the stator 2 is realized using the transistor. One or more such half-bridge or full-bridge circuits are usually arranged in the chip housing 424 of the circuit breaker 420, and a driver can also be optionally provided in the chip housing 424. The chip housing 424 of the circuit breaker 420 is attached to the mounting surface 421 on the front surface 411 of the circuit board 41. A plurality of connection pins (not shown) are provided on the chip housing 424 of the circuit breaker 420, and through the connection pins, the electronic components of the circuit breaker 420, that is, for example, a transistor, can be electrically connected to the conductor tracks or electrical connectors on the circuit board 41. The electronic components of the circuit breaker 420 are electrically insulated from the chip housing 424. The mounting surface 421 that also functions as the cooling surface of the circuit breaker 420 is usually at the ground potential. The thermal connection element 85 extends from the mounting surface 421 through the circuit board 41 to the back surface 412 of the circuit board 41.

[0118] In the operating state, the circuit breaker 420 represents one of the main heat sources, even if it is not the main heat source of the control device 40. Since the circuit breaker 420 is arranged in the area of the circuit board 41 that abuts against the web 8 of the control unit housing 102, the heat generated by the circuit breaker can be very efficiently and reliably dissipated into the web 8 and then into the housing 10 through the thermal connection element 85. As a result, especially the control unit 40 is reliably protected from overheating.

[0119] As can be recognized in Figure 9, additional thermal connection elements 86 are provided, and each of the additional thermal connection elements preferably extends from the front surface 411 to the back surface of the circuit board 41. The additional thermal connection elements 86 are arranged outside the area where the individual mounting surface 421 for the circuit breaker 420 is located. The additional thermal connection elements 86 act to selectively dissipate heat from other areas of the front surface 411 of the circuit board 41 to the back surface 412 of the circuit board 41. Such other areas are areas where the circuit breaker 420 is not arranged. The additional thermal connection elements 86 are also preferably arranged to terminate at, i.e., thermally couple to, the web 8. Each of the additional thermal connection elements 86 is preferably designed as a through-hole plating.

[0120] A further advantageous measure is to provide contact pads 87 on the back surface 412 of the circuit board, each for a mounting surface 421, and the contact pads thermally couple all the thermal connection elements 85 belonging to this mounting surface 421 to each other (see Figure 9). Each contact pad 87 abuts against one of the webs 8. Each contact pad 87 is made of, for example, copper. Each contact pad 87 is designed, for example, as a copper film or a copper layer, and all of them thermally connect the ends of all the thermal connection elements 85 belonging to the same circuit breaker 420 to each other on the back surface 412 of the circuit board 41. By using such large-area contact pads 87, heat can be dissipated particularly well into the web 8 and thus into the housing 10.

[0121] Figure 11 shows a plan view of the back surface 412 of a modified example of the circuit board 41. Figure 12 shows a schematic cross-sectional view of this modified example of the circuit board 41 for better understanding, and the cross-section is created along the line XII-XII of Figure 11.

[0122] In this modified example, a thermal conduction layer 88 is arranged between the back surface 412 of the circuit board 41 and each web 8 with which the circuit board 41 is in contact, and the thermal conduction layer can transfer heat from the circuit board 41 to each web 8 and thus to the housing 10.

[0123] FIG. 13 shows a perspective view of one of the heat conductive layers 88 for better understanding.

[0124] The shape of the heat conductive layer 88 preferably corresponds to the surface of the web 8 with which the heat conductive layer 88 abuts, such that the entire surface of the web 8 where the circuit board 41 abuts is covered by the heat conductive layer 88.

[0125] The heat conductive layer 88 improves the thermal connection with the housing 10. The heat conductive layer 88 is preferably designed as a film made of a thermally conductive material and is disposed between the circuit board 41 and each web 8 with which the circuit board 41 abuts. The heat conductive layer 88 designed as a film can be mounted or soldered, for example, to the back surface 412 of the circuit board 41. It should be understood that a plurality of heat conductive layers 88 can be provided such that such heat conductive layers 88 are disposed between all the webs 8 with which the circuit board 41 abuts and the circuit board. Heat is transferred by the heat conductive layer 88 to the web 8 and thus to the housing 10 over a wide area, thereby reducing the thermal boundary resistance. The heat conductive layer 88 preferably designed as a film is made of a material with high thermal conductivity and can be easily deformed (ductile), so that the heat conductive layer 88 can also compensate for small unevenness and mechanical tolerances. For the heat conductive layer 88, a metal material such as copper or silver is particularly suitable. The advantage of designing the heat conductive layer 88 as a copper film is that soldering is easy. To further improve the solderability, the copper film can also be coated with a noble metal such as gold.

[0126] Hereinafter, a method of assembling the magnetic levitation device 1 in a very simple manner will be described. The assembly can be performed, for example, as follows. The sensor substrate 7 on which the magnetic field sensor is disposed and mounted is inserted into the holding device 9.

[0127] Subsequently, the holding device 9 can be completely filled with a potting material such that the sensor substrate 7 is completely covered with the potting material.

[0128] Guide the coil core 25 through the notch 91 of the holding device 9 and the concentrated winding 61. Arrange the magnetic back iron 22 between the first ends 261 of the longitudinal legs 26. Insert the holding device 9, the back iron 22, and the coil core 25 with the concentrated winding 61 arranged therein into the stator housing 101 of the housing 10 in the first mounting direction in the axial direction A (from the left side in FIG. 2). In this step, guide the electrical connection element 76 through the stator housing 101 in parallel with the longitudinal legs 26 of the coil core 25 into the control unit housing 102.

[0129] When arranging the holding device 9, the winding 61, the back iron 22, and the coil core 25 in the stator housing 101 of the housing 10, dispose the storage container 21 on the housing 10 and arrange the seal 201 between the storage container 21 and the housing 10, thereby connecting to the housing 10 in a sealed state, preferably an airtight sealed state.

[0130] Subsequently, fill the housing 10 of the magnetic levitation device 1 with a thermally conductive potting material. The high thermal conductivity potting material preferably has particularly excellent thermal conductivity in order to quickly and surely dissipate the heat generated in the operating state into the housing 10 and then dissipate the heat from the housing 10 mainly by convection. As the thermally conductive potting material, for example, polyurethane, epoxy resin, acrylic resin, or polyester is suitable.

[0131] After filling the stator housing 101 of the housing 10 with the second potting material, insert the control unit 40 into the control unit housing 102 of the housing 10 in the second mounting direction. Here, the second mounting direction is opposite to the first mounting direction. The control unit 40 is thus inserted into the control unit housing 102 from the right side according to the illustration in FIG. 2. Connect the electrical connection element 76 to the control unit 40.

[0132] When arranging the control unit 40 within the control unit housing 102 of the housing 10, dispose the housing cover 11 on the housing 10, connect it to the housing 10 in a sealed state, preferably a hermetically sealed state, and arrange the sealing element 105 between the housing cover 11 and the housing 10. The housing cover 11 is attached to the housing 10 using, for example, a plurality of screws 111 (FIG. 1).

[0133] Optionally, for applications using, for example, highly corrosive, erosive, or explosive fluids, the control unit housing 102 of the housing 10 can also be filled with potting material. When also filling the control unit housing 102, the filling is performed before disposing the housing cover 11 on the housing 10 and firmly connecting it to the housing 10.

[0134] The magnetic levitation device 1 according to the present invention is particularly suitable not only for centrifugal pumps but also for mixing devices for mixing fluid substances, for example, stirring devices for mixing liquids in a tank, for blowers, or for devices for supporting and rotating wafers during, for example, semiconductor production.

Claims

1. A magnetic levitation device for magnetically levitating a rotor (3) having a disk-shaped or ring-shaped magnetically effective core (31) in a non-contact manner, the magnetic levitation device comprising a housing (10), a stator (2), and a control device (40); the stator (2) comprises a plurality of coil cores (25), each of which has a longitudinal leg (26) extending from a first end (261) to a second end (262) in an axial direction (A), and a transverse leg (27) disposed at the second end (262) of the longitudinal leg and extending in a radial direction perpendicular to the axial direction (A); at least one concentrated winding (61) is provided on each longitudinal leg (26), the winding surrounding each longitudinal leg (26); the stator (2) further comprises a cup-shaped recess (211) into which the rotor (3) can be inserted, the cup-shaped recess (211) being disposed at an axial end of the stator (2); the control unit (40) comprises a circuit board (41) having a front surface (411) and a back surface (412), a circuit breaker (420) for controlling the winding (61) is disposed on the front surface (411); the housing (10) comprises an outer wall (15), a stator housing (101) that receives the stator (2), a control unit housing (102) that receives the control unit (40), and a separation wall (103) that separates the stator housing (101) from the control unit housing (102); A magnetic levitation device, characterized in that at least one web (8) is arranged on the separation wall (103) adjacent to the outer wall (15), the web protruding into the control unit housing (102), the back surface (412) of the circuit board (41) is supported on the web (8), a plurality of circuit breakers (420) are arranged in areas of the circuit board (8) where the back surface (412) of the circuit board (41) is supported on the web (8), and a thermal connection element (85) for dissipating heat is provided between the plurality of circuit breakers (420) and the web (8).

2. 2. The magnetic levitation device according to claim 1, wherein the outer wall (15) of the housing (10), the separating wall (103) and the web (8) are designed as an integral unit.

3. 3. The magnetic levitation device of claim 1 or 2, wherein each circuit breaker (420) is disposed on a respective separate mounting surface (421), each mounting surface (421) is connected to the rear surface (412) of the circuit board (41) via a plurality of the thermal connection elements (85), each thermal connection element (85) extending from the front surface (411) to the rear surface (412) of the circuit board (41).

4. 4. The magnetic levitation device of claim 3, wherein additional thermal connection elements (86) are provided, each of the additional thermal connection elements extending from the front surface (411) to the back surface (412) of the circuit board (41), and each of the additional thermal connection elements (86) being positioned outside the separate mounting surface (421).

5. A magnetic levitation device as described in claim 3 or 4, wherein contact pads (87) are provided on the back surface (412) of the circuit board (41) for each mounting surface (421), thermally coupling all thermal connection elements (85) belonging to the mounting surface (421) to each other.

6. A magnetic levitation device as described in any one of claims 1 to 5, wherein a thermally conductive layer (88) is disposed between the web (8) and the back surface (412) of the circuit board (41), and the thermally conductive layer is capable of transferring heat from the circuit board (41) to the housing (10).

7. 7. The magnetic levitation device according to claim 6, wherein the heat conducting layer (88) is designed as a film attached to the back side (412) of the circuit board (41).

8. The magnetic levitation device of claim 6 or 7, wherein the thermally conductive layer (88) is made of a metallic material.

9. A magnetic levitation device as described in any one of claims 1 to 8, wherein the control unit housing (102) of the housing (10) is designed so that the internal space has a substantially rectangular or square cross-sectional area perpendicular to the axial direction (A).

10. 10. The magnetic levitation device according to claim 1, wherein the stator housing (101) of the housing (10) is designed such that the internal space has a substantially round cross-sectional area perpendicular to the axial direction (A).

11. The magnetic levitation device according to any one of claims 1 to 10, wherein a housing cover (11) is arranged at one axial end of the magnetic levitation device, the cover covering the control unit housing (102).

12. 12. A magnetic levitation device as claimed in any one of claims 1 to 11, wherein the stator (2) has a housing (21) forming one axial end of the stator (2), the housing (21) having the cup-shaped recess (211).

13. 13. A magnetic levitation device as claimed in any one of claims 1 to 12, wherein the separation wall (103) comprises an internal cup (13) designed substantially cylindrically, the internal cup being arranged radially inward with respect to the winding (61) in an internal space surrounded by the winding (61).

14. 14. The magnetic levitation device according to claim 1, wherein the housing (10) is designed so that the coil core (25) on which the concentrated winding (61) is arranged can be inserted into the stator housing (101) in a first mounting direction in the axial direction (A) and the control unit (40) can be inserted into the control unit housing (102) in a second mounting direction, the first mounting direction facing in a direction opposite to the second mounting direction.

15. 15. A magnetic levitation device as claimed in any one of claims 1 to 14, wherein the stator (2) is designed to generate a torque capable of magnetically driving the rotor (3) to rotate about the axial direction (A) without contact.

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