Rotor capable of magnetic levitation and rotary machine with such rotor

Abstract

To propose a rotor capable of being magnetically levitated for a rotary machine, and to propose a rotary machine with such a rotor.SOLUTION: A rotor is proposed for a rotary machine with a magnetically-levitated rotor. The rotor can be magnetically levitated, and the rotor has a magnetically-effective core (2) and a sheath material (3) made of a thermoplastically processible fluoropolymer. The sheath material (3) completely encloses the magnetically-effective core (2). The magnetically-effective core (2) comprises at least one permanent magnet (21), and each permanent magnet (21) has a metallic coating (6) for protection against acidic or chemically-corrosive substances. A plastic coating (7) is provided between the metallic coating (6) and the sheath material (3), and the plastic coating (7) consists of a polymer belonging to the family of parylenes. Further, a rotary machine (100) having such a rotor is proposed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The invention relates to a rotor for a rotary machine having a magnetically levitated rotor, the rotor being magnetically levitable, and also to a rotary machine according to the preambles of the independent claims of the respective category. [Background technology]

[0002] Rotary machines with magnetically levitated rotors, such as centrifugal pumps or mixers or agitators, are used in many technical fields, particularly for applications where high-purity fluids are conveyed, stirred, or mixed without contaminating the fluid with wear particles from mechanical bearings. In the semiconductor industry, for example, magnetically levitated rotors are used to convey ultra-pure water as well as acidic, oxidizing, or other chemically corrosive substances when used in the semiconductor industry for manufacturing or processing semiconductor structures. It is important that metal ions do not reach the liquid from the magnetically levitated rotor, as such metal ions can alter the doping of the semiconductor.

[0003] For the design of rotary machines with magnetically levitated rotors, in particular centrifugal pumps, devices are known in which the rotor is levitated in a contactless manner by individual magnetic bearings while the rotor's rotation is driven by a separate drive unit. In this case, each magnetic bearing typically comprises a bearing stator that interacts with the rotor's magnetically active core to magnetically levitate the rotor. The drive unit comprises a drive stator that rotates the rotor according to the principle of an electromagnetic rotary drive.

[0004] However, rotary machine designs are also known that have a magnetically suspended rotor without a separate magnetic bearing, where the bearing and drive functions are realized by the same stator. The term "bearingless motor" was established for such designs because the rotor does not have a separate magnetic bearing. The bearing and drive functions cannot be separated from each other. These particularly efficient bearingless motors are characterized by a particularly compact design and the simultaneous realization of the "contactless" concept.

[0005] Thus, a bearingless motor is an electromagnetic rotary drive in which the rotor is fully magnetically suspended relative to the stator and does not have a separate magnetic bearing. For this purpose, the stator is designed as both a bearing stator and a drive stator, which is both the stator of the electric drive and the stator of the magnetic bearing. A rotating magnetic field can be generated using the electrical windings of the bearing stator and the drive stator, which, on the one hand, applies a torque to the rotor, causing it to rotate, and, on the other hand, applies a freely adjustable lateral force to the rotor so that its radial position can be actively controlled or adjusted.

[0006] Rotary machine rotors, especially when designed as pumps, mixers, or agitators, are often one-piece rotors, which are both the rotor of the electromagnetic drive and the rotor of the pump or mixer, thereby affecting the fluid.

[0007] Different concepts for the design of the rotor's magnetically effective core are known. For example, the rotor's magnetically effective core can consist solely of one or more permanent magnets, so that the entire rotor's magnetically effective core is made of permanent magnetic material. However, designs are also known in which the magnetically effective core comprises one or more permanent magnets combined with a soft magnetic component. Typically, the soft magnetic component is made of iron, nickel-iron, or silicon-iron.

[0008] Whether a rotating machine, such as a centrifugal pump, is designed with individual magnetic bearings or according to the bearingless motor concept, the transport of acidic or chemically corrosive substances makes it particularly important that the magnetically active core of the rotor, and in particular the permanent magnets, are also protected from such corrosive substances. Materials typically used for permanent magnets, such as neodyne, samarium, or cobalt, generally have very low resistance to such corrosive substances.

[0009] Acidic or other chemically corrosive substances that must be used and delivered in semiconductor manufacturing include, for example, ozonated water (O3, dissolved in H2O), sulfuric acid (H2SO4), phosphoric acid (H3PO4), hydrochloric acid (HCl), hydrofluoric acid (HF), nitric acid (HNO3), ozone (O3), or mixtures such as sulfuric acid (H2SO4) and hydrogen peroxide (H2O2) or sulfuric acid (H2SO4) and nitric acid (HNO3), etc. To make matters worse, these corrosive substances often must be provided at high temperatures, for example, 150°C to 200°C or higher.

[0010] To protect against such corrosive substances, it is known to provide the magnetically active core of the rotor, in particular the permanent magnet(s), with a plastic coating of fluorocarbons, since these hydrocarbons exhibit very good resistance to chemically corrosive substances, in particular the acids mentioned above.

[0011] However, fluorocarbons very often do not form a sufficient barrier to the gaseous components of chemicals. Thus, fluorocarbon encapsulation has very limited barrier effect against, for example, ozone (O3), which may be present in the transport mixture of significant amounts of sulfuric acid and ozone (H2SO4 with O3). Furthermore, studies have shown that corrosion occurs even with such fluorocarbon coatings after a relatively short period of operation, especially on the rotor's permanent magnets. This can result in rotor expansion, deterioration of the metal coating, and even chipping of portions of the rotor core or coating, potentially resulting in the complete destruction of the rotor's magnetically active core.

[0012] It is therefore proposed in EP 2549113 to provide the permanent magnets of the rotor with a double coating, i.e. an inner metallic coating completely surrounding the permanent magnet, and an outer coating of fluorocarbon completely surrounding the metallic coating.

[0013] The idea is that the outer plastic covering protects the permanent magnet or magnetically effective core from acids, usually liquids, and the inner metallic covering protects the magnetically effective core from gaseous components that can penetrate the plastic covering relatively well.

[0014] Although the double-layer cladding concept itself has proven itself, there is still a need for improvement. The thick metal cladding of the rotor permanent magnets proposed in EP 2549113 is relatively difficult to achieve because the welding of the individual cladding components must be gas-tight. On the other hand, the energy input during welding must be kept low enough to avoid changing the structure of the permanent magnet material. This problem is compounded by the fact that the metal cladding must be relatively close to the permanent magnets, because the magnetic air gap cannot be increased during magnetic levitation without significant power loss. The heat required to weld the cladding is then dissipated directly into the rotor permanent magnets. In addition, ozone, hydrogen, or acid vapors can diffuse through the plastic and corrode the metal cladding. If the rotor's metal cladding corrodes, metal ions can diffuse through the plastic cladding into the transport fluid, contaminating it. In semiconductor industry applications, such metal ions in fluids can have extremely negative consequences, since, for example, even very low concentrations of dissolved metal ions can alter the doping of semiconductor structures being processed in an uncontrolled manner, and in the worst case, can render the semiconductor product unusable.

[0015] Therefore, great efforts have been made to better protect the magnetically active core of the rotor against acids and other chemically corrosive substances, while at the same time avoiding the above-mentioned problems of welding the metal cladding of the permanent magnets. To this end, a wide variety of metal layers have been electrolytically applied to the permanent magnets, and their corrosion resistance has been tested. However, surprisingly, even electrolytically applied metal cladding using, for example, gold or rhodium, which are considered to be very inert, has not produced truly satisfactory results. After a relatively short service life of, for example, 100 to 200 hours, extensive corrosion can occur on the rotor.

[0016] It has been suggested that certain substances with very small molecules, such as hydrochloric acid (HCl) or hydrofluoric acid (HF) or ozone (O3), can diffuse into the coating through lattice or microstructural defects in the metal layer, such as gas bubbles or capillary cracks, and corrode the permanent magnets or magnetically active core of the rotor, causing the rotor to corrode from the inside. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] European Patent No. 2549113 Summary of the Invention [Problem to be solved by the invention]

[0018] The present invention is specific to this problem.

[0019] Starting from this prior art, the object of the present invention is therefore to propose a rotor capable of magnetic levitation for a rotary machine in which the magnetically effective core of the rotor, and in particular the permanent magnets, are particularly well protected against oxidizing and acidic substances or other chemically corrosive substances. Furthermore, the present invention seeks to propose a rotary machine having such a rotor. [Means for solving the problem]

[0020] The object of the invention, which solves this problem, is characterized by the features of the independent claims of the respective categories.

[0021] According to the present invention, for a rotary machine having a magnetically levitated rotor, a magnetically levitable rotor is proposed, the rotor having a magnetically active core and a covering made of a thermoplastically processable fluoropolymer, the covering completely surrounding the magnetically active core, the magnetically active core comprising at least one permanent magnet, each permanent magnet having a metal coating for protection against acidic or chemically corrosive substances, and a plastic coating provided between the metal coating and the covering, the plastic coating consisting of a polymer belonging to the parylene group.

[0022] Preferably, the metallic coating adheres directly to the permanent magnet.

[0023] Through very complex and extensive research, it has been shown that this precise combination of a metallic coating of the permanent magnet directly adhered to the permanent magnet, with a fluoropolymer outer coating and a parylene coating in between, ensures particularly good and long-lasting protection of the rotor's magnetically active core against acids, acidic fluids, and other chemically corrosive substances, such as ozone or hydrogen. This special combination protects the rotor's magnetically active core against both corrosive liquid components, such as liquid acid, and gaseous components. Specifically, the diffusion of substances with very small molecules, such as hydrogen (H), ozone (O), hydrofluoric acid (HF), or hydrochloric acid (HCl), into the rotor's magnetically active core or permanent magnet is also prevented, or at least significantly reduced. Compared to the fluoropolymer of the outer coating, the parylene's polymer chains are significantly longer, which allows them to form a much better diffusion barrier than fluoropolymers.

[0024] Parylene is also used as the trade name for a group of poly(p-xylylene) polymers produced by chemical vapor deposition. The starting material is p-xylene (also known as xylene or dimethylbenzene) or its halogenated derivatives. Different parylenes are distinguished depending on which substituents are attached to the benzene ring. In the base product, poly-p-xylylene, known as Parylene N, the benzene ring contains only aromatic hydrogen atoms, i.e., each of the four radicals on the benzene ring is a hydrogen atom. In addition, other commercially available products include Parylene C, Parylene D, and Parylene HT. In Parylene C, one aromatic hydrogen atom is replaced with a chlorine atom, in Parylene D, two aromatic hydrogen atoms are replaced with one chlorine atom each, and Parylene HT is a halogenated derivative in which each alpha hydrogen atom of the dimer is replaced with a fluorine atom.

[0025] The permanent magnet or magnets of the rotor's magnetically effective core are preferably made of neodyne-iron-boron (NdFeB) or samarium-cobalt (SmCo) alloy.

[0026] It has proven advantageous if the metal coating, which adheres directly to the rotor, comprises at least one layer made of nickel or gold or rhodium.

[0027] Particularly good protection can be achieved when the metal coating comprises multiple, specifically at least three, coatings arranged one on top of the other, with the innermost layer being applied directly to the surface of the permanent magnet and preferably consisting of nickel. Nickel is particularly preferred because it adheres well to NdFeB-based alloys as well as SmCo-based alloys. Nickel is also preferred as the outermost metal layer because parylene adheres better to nickel than to precious metals such as gold or rhodium.

[0028] In a preferred embodiment, the metal coating comprises exactly three layers arranged one above the other, the innermost and outermost layers each consisting of nickel, and the intermediate layer in between preferably consisting of copper or gold or rhodium.

[0029] In multilayer metal coatings, the innermost layer is applied first to the surface of the permanent magnet. Subsequently, an intermediate layer is applied, which can be used, for example, to fill air bubbles, capillary cracks, or other microstructural defects in the innermost coating. The intermediate layer then forms a particularly flat and smooth base for the outermost layer. Preferably, the metal coating is deposited on the surface of the permanent magnet by galvanic techniques (electroplating) or by currentless metal vapor deposition (chemical vapor deposition without external current).

[0030] If the metal coating comprises three layers, the following layer combinations are particularly preferred, from the inside, i.e. from the surface side of the permanent magnet to the outside: nickel (Ni), copper (Cu), nickel (Ni), or nickel, gold, nickel, or nickel, rhodium (Rh), nickel. If the metal layer coating consists of only one layer, this is preferably nickel, gold, or rhodium.

[0031] The total thickness of the metal coating is preferably 30 to 100 micrometers, particularly preferably 50 to 60 micrometers.

[0032] Regarding the coating material, it is preferred that the coating material consists of perfluoroalkoxy polymer (PFA) or ethylene chlorotrifluoroethylene (ECTFE) or polyvinylidene fluoride (PVDF). In addition to being resistant to acids, these thermoplastically processable fluoropolymers have the distinct advantage that they can be injection molded and welded, for example by infrared welding. This is advantageous for rotor manufacturing.

[0033] The fluoropolymer coating preferably comprises at least two parts welded together, preferably by infrared welding. To protect the Parylene plastic coating from excessive heat input, especially during the welding process, it is advantageous to provide a thermal protection film, preferably a polyimide film, between the plastic coating and the coating. Materials available under the trade name Kapton, for example, are suitable for this purpose.

[0034] According to a preferred embodiment, the plastic coating is made of fluorinated parylene, preferably aliphatic fluorinated parylene. Specifically, two variants of fluorinated parylene are currently commercially available: an aliphatic fluorinated variant called Parylene AF4 and an aromatic fluorinated variant called Parylene VT4. The aliphatic fluorinated parylene is a variant in which two hydrogen atoms in the aliphatic carbon bond between the benzene rings are replaced with two fluorine atoms. To this end, the alpha hydrogen atoms of the dimer are replaced with fluorine atoms to produce parylene. In the aromatic fluorinated variant, each aromatic hydrogen atom is replaced with a fluorine atom, i.e., each of the four radicals on the benzene ring is a fluorine atom.

[0035] Fluorinated parylene, particularly aliphatic fluorinated parylene, has the advantage of being highly thermally stable, i.e., resistant to high temperatures and capable of being exposed to temperatures up to 450°C without degradation, at least for short periods of time. Of course, when using fluorinated parylene, a polyimide thermal protection film can be provided between the parylene plastic coating and the covering material.

[0036] Preferably, the metallic coating completely surrounds the magnetically effective core, i.e., the entire magnetically effective core is completely surrounded by the metallic coating. According to a first embodiment, the magnetically effective core of the rotor consists of only one permanent magnet, for example a permanent magnet ring. In this case, each surface of the permanent magnet is completely provided with a metallic coating so that the entire permanent magnet is completely covered by the metallic coating, i.e., completely surrounded or encapsulated by the metallic coating.

[0037] It is also preferred that the plastic coating completely surround the magnetically effective core. Typically, plastic coatings made of parylene are produced by vapor deposition as a polymer layer on the substrate to be coated. Thus, for example, the magnetically effective core of a rotor or permanent magnet is first provided with a metal coating, and then a plastic coating of parylene is deposited on this metal coating.

[0038] In a preferred embodiment, the metal coating is applied directly onto each permanent magnet, with each permanent magnet being completely surrounded by the metal coating applied directly onto it.

[0039] Furthermore, it is preferred that the plastic coatings be applied directly onto the metal coatings, with each metal coating being completely surrounded by the plastic coating applied directly thereon.

[0040] As already mentioned, the magnetically effective core consists of a permanent magnet of the first variant, which is preferably designed in one piece, particularly preferably in the form of a ring.

[0041] According to a preferred embodiment, the covering comprises a cup-shaped housing part that receives the magnetically effective core and a cover that is welded to the housing part, and the cup-shaped housing part is preferably designed so that there is an air gap between the magnetically effective core and the housing part. If the magnetically effective core is provided with a metal coating and a plastic coating, this air gap has a radial width of, for example, about 0.1 mm between the wall of the housing part and the covered magnetically effective core. An air gap is also provided in the axial direction, i.e., at the bottom or cover of the cup-shaped housing part, and has an axial width of about 0.5 to 1 mm.

[0042] Furthermore, the present invention proposes a fluid-influencing rotary machine, in particular a centrifugal pump or mixer, having a magnetically levitable rotor and stator, whereby the rotor can be magnetically driven without contact to rotate around an axial direction in an operating state, the rotor being magnetically levitated and designed according to the present invention.

[0043] The rotating machine is preferably designed as a bearingless motor, and the stator is designed as a bearing stator and a drive stator, whereby the rotor can be driven magnetically without contact in the operating state and can be suspended magnetically without contact at least in the radial direction relative to the stator.

[0044] Further advantageous measures and embodiments of the invention result from the dependent claims.

[0045] In the following, the invention will be explained in more detail by means of embodiments and with reference to the drawings, in which: FIG. [Brief explanation of the drawings]

[0046] [Figure 1] 1 is a cross-sectional view of a first embodiment of a rotary machine according to the invention, having a first embodiment of a rotor according to the invention; [Figure 2] FIG. 2 is a cross-sectional view of the magnetically levitable rotor of FIG. 1. [Figure 3] FIG. 3 is an enlarged view of detail I of FIG. 2. [Figure 4] 3 is a cross-sectional view of a second embodiment of a rotary machine according to the invention, having a second embodiment of a rotor according to the invention; [Figure 5] FIG. 3 is a cross-sectional view of the magnetically levitable rotor of FIG. 2. [Figure 6] 6 is a cross-sectional view of the rotor of FIG. 5 taken along section line VI-VI of FIG. 5. [Figure 7] FIG. 6 is a schematic cross-sectional view of a first variant of the rotor of FIG. 5. [Figure 8] FIG. 6 is a schematic cross-sectional view of a second variant of the rotor of FIG. 5. [Figure 9] FIG. 6 is a schematic cross-sectional view of a third variant of the rotor of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0047] 1 shows a first embodiment of a rotary machine according to the invention in a first cross-sectional view, having a first embodiment of a rotor according to the invention. Here, the rotary machine is designed as a centrifugal pump and is generally designated by the reference numeral 100. Such a centrifugal pump 100 can be used to convey acidic fluids or chemically corrosive substances, in particular in the semiconductor industry. Such fluids may include sulfuric acid (H2SO4), phosphoric acid (H3PO4), hydrochloric acid (HCl), hydrofluoric acid (HF), nitric acid (HNO3), ozone (O3), or mixtures of, for example, sulfuric acid (H2SO4) and hydrogen peroxide (H2O2) or sulfuric acid (H2SO4) and nitric acid (HNO3).

[0048] The centrifugal pump 100 comprises a pump housing 101 having an inlet 102 and an outlet 103 for the fluid to be conveyed. A first embodiment of a magnetically levitable rotor according to the invention is provided within the pump housing 101, this rotor being generally designated by the reference numeral 1. For better clarity, FIG. 2 shows a cross-sectional view of the magnetically levitable rotor 1 of FIG. 1. The rotor 1 has a magnetically effective core 2 with at least one permanent magnet 21 for driving the rotation of the rotor 1 about a set axis of rotation defining an axial direction A. The direction perpendicular to the axial direction A is described as the radial direction.

[0049] In a first embodiment, the magnetically effective core 2 consists solely of a permanent magnet 21, which is designated herein as a ring-shaped permanent magnet 21. Preferably, the ring-shaped permanent magnet 21 is one piece. However, it is also possible for the permanent magnet 21 to comprise several segments which complement each other to form a ring. In operation, the ring-shaped permanent magnet 21 is arranged to extend around a set rotation axis.

[0050] The rotor 1 further comprises a sheath 3 made of a thermoplastically processable fluoropolymer, which completely surrounds the magnetically effective core 2 such that the magnetically effective core 2 is completely embedded in and encapsulated by the sheath 3. The sheath 3 is made of perfluoroalkoxy polymer (PFA). Alternatively, the sheath 3 can be made of ethylene chlorotrifluoroethylene (ECTFE) or polyvinylidene fluoride (PVDF). The sheath 3 is provided with a plurality of vanes 4, by which a fluid can be conveyed from an inlet 102 to an outlet 103. Furthermore, a cover plate 5 is provided, which covers the vanes 4 with a surface facing away from the sheath 3. The pump housing 101 is preferably made of plastic. This may be the same plastic as the sheath 3 or a different plastic. The pump housing 101 preferably consists, at least essentially, of a fluoropolymer. Plastics or polymers that are not thermoplastically processable, i.e., that cannot be welded or injection molded, are also suitable for the pump housing 101, particularly fluoropolymers.

[0051] The pump housing 101 is designed to be insertable into the stator 104, so that the rotor 1 can be magnetically driven in a contactless manner to rotate about the axial direction A and can be magnetically suspended in a contactless manner at least in the radial direction. The rotor 1 is therefore designed as a one-piece rotor 1, which forms both the pump rotor 1 and the rotor 1 of the electromagnetic rotary drive.

[0052] The stator 104 has, in a manner known per se, several coil cores 105 with coils or windings 106, by means of which the rotor 1 can be driven magnetically and contactlessly in operation. The coil cores 105 are connected by ends 107, which preferably consist of iron. In a first embodiment, the stator 104 is designed as a bearing stator and a drive stator 104, by means of which the rotor 1 can be driven magnetically and contactlessly in operation and can be magnetically levitated without contact with respect to the stator 104. The stator 104 and the rotor 1 therefore form an electromagnetic rotary drive, which is preferably designed according to the principle of a bearingless motor.

[0053] In a bearingless motor, the rotor 1 can be driven magnetically without contact and can be levitated magnetically without contact relative to the stator 104. For this purpose, the stator 104 is designed as a bearing stator and a driving stator 104, whereby the rotor 1 can be driven magnetically without contact about a set rotation axis, i.e. it can rotate and be levitated magnetically without contact relative to the stator 104.

[0054] Since bearingless motors are well known to those skilled in the art, a detailed description of their function is no longer necessary. The term "bearingless motor" refers to the fact that the rotor 1 is fully magnetically suspended and does not have a separate magnetic bearing. For this purpose, the stator 104 is designated as both a bearing stator and a drive stator 104, which is both the stator of the electric drive and the stator of the magnetic bearing. The stator 104 includes windings 106, which generate a magnetic rotation field that, on the one hand, applies a torque to the rotor 1, causing it to rotate, and, on the other hand, applies a freely adjustable lateral force to the rotor 1, so that its radial position, i.e., its position in a radial plane perpendicular to the axial direction A, can be actively controlled or adjusted. Thus, at least three degrees of freedom of the rotor 1 are actively controllable. The rotor 1 is at least passively magnetized with respect to axial deflection in the axial direction A, i.e., this is not controllable but is stabilized by magnetic resistance forces. Depending on the design, the rotor 1 can also be passively magnetically stabilized with respect to the remaining two degrees of freedom, namely tilt relative to a radial plane perpendicular to the set axis of rotation.

[0055] In contrast to conventional magnetic bearings, the magnetic bearing and drive of a bearingless motor are realized via electromagnetic rotating fields, the sum of which generates on the one hand a driving torque on the rotor 1 and also a freely adjustable lateral force that allows the radial position of the rotor 1 to be controlled. These rotating fields can be generated separately, i.e., using different coils, or the rotating fields can also be generated by mathematically superimposing the required currents or voltages and then using a single coil system. A distinctive feature of bearingless motors is that the drive function cannot be separated from the bearing function. This is a major difference from individual magnetic bearing designs, where the drive function is separated from the bearing function.

[0056] To mount the pump housing 101 with the rotor 1 in the stator 104, the stator 104 has a substantially cylindrical recess into which the pump housing 101 can be inserted, so that a coil core 105 with windings 106 surrounds the rotor 1. The rotor 1 is centrally located between the stator poles formed by the coil core 105. The rotor 1 and the stator 104 therefore represent an electromagnetic rotary drive, designed according to the internal rotor principle.

[0057] In the embodiment described herein, the centrifugal pump 100, more precisely the rotary drive formed by the stator 104 and the rotor 1, is designed as a so-called temple motor. A feature of the temple motor design is that the stator 104 comprises a number of individual coil cores 105, each of which is L-shaped and has a longitudinal leg and a transverse leg. Each longitudinal leg extends in the axial direction A from a first end to a second end, from which the transverse legs extend radially inward to form stator poles. The first ends of all of the longitudinal legs (which are the lower ends according to the view in FIG. 1) are connected to each other by a terminal portion 107. The terminal portion 107 comprises several segments, each connecting the first end of one coil core 105 to the first end of an adjacent coil core 105. The individual coil cores 105 are preferably arranged so that they are equidistantly arranged around the rotor 1 in a circular manner. During operation, the rotor 1 is levitated in a magnetically contactless manner between the stator poles pointing radially inward. The magnetically effective core 2 of the rotor is at the same height as the stator poles in the axial direction A. The parallel longitudinal legs of the coil core 105, all extending parallel to the axial direction A and surrounding the rotor 1, resemble the pillars of a temple, hence the name temple motor.

[0058] Another feature of the temple motor is that the windings 106 of the stator 104 are each arranged around the longitudinal legs of the coil core 105, and are thus arranged below and outside the magnetic rotor plane according to the figure. The magnetic rotor plane is the magnetic center plane of the magnetically effective core 2 of the rotor 1. This is the plane perpendicular to the axial direction A in which the rotor 1 or its magnetically effective core 2 is levitated in operation when the rotor 1 is not tilted. In general, the magnetic rotor plane is the geometric center plane of the magnetically effective core 2 of the rotor 1, perpendicular to the axial direction A.

[0059] Preferably, the windings 106 are located completely below the magnetically effective core 2. Thus, the windings 106 are not located in the plane in which the rotor 1 is driven or levitated in operation. In contrast to other electromagnetic rotary drives in which the stator windings are arranged so that their coil axes are each in the plane of the magnetic rotor, i.e., in the plane in which the rotor is levitated, the windings 106 of the stator 104 are arranged in the temple motor so that the axes of the windings 106 are perpendicular to the plane of the magnetic rotor and therefore parallel to the axial direction A.

[0060] It is clear that the invention is not limited to embodiments such as the temple motor, and many other embodiments of the stator 104 are possible. The only important thing is that the rotor 1 can be magnetically and contactlessly driven to rotate about its axial direction in the operating state.

[0061] The rotor 1 will now be described in more detail with reference to FIGS. 2 and 3, where FIG. 3 is an enlarged view of detail I of FIG.

[0062] As already mentioned, in the first embodiment, the magnetically effective core 2 consists of a ring-shaped permanent magnet 21, i.e., the magnetically effective core 2 is identical to the permanent magnet 21. The permanent magnet 21 preferably consists of a neodyne-iron-boron (NdFeB) alloy, but may also consist of other materials commonly used for permanent magnets, such as a samarium-cobalt (SmCo) alloy.

[0063] The permanent magnet 21 has a metal coating 6 which acts as a protection against gaseous components, in particular acidic or chemically corrosive substances, preventing or at least significantly reducing the diffusion of such components into the permanent magnet as much as possible. The metal coating 6, which will be explained in more detail below, is provided directly on the surface of the permanent magnet 21 so that all surfaces of the permanent magnet 21 are provided with the metal coating 6 and the permanent magnet 21 is completely surrounded by the metal coating 6. The metal coating 6 is a hermetic seal for the permanent magnet 21 and prevents any substances from coming into direct contact with the permanent magnet 21.

[0064] Preferably, the metal coating is deposited directly onto each surface of the permanent magnet 21 by galvanic techniques (electroplating) or by currentless metal deposition (chemical vapor deposition without external current).

[0065] A plastic coating 7 is applied directly onto the metal coating 6 and consists of a polymer belonging to the parylene family. These parylenes, commercially available under the trade names Parylene N, Parylene C, and Parylene D, are particularly suitable for plastic coatings. Parylene N is the base product of this polymer family. Parylene N is a completely linear polymer, poly(paraxylylene). Parylene C and Parylene D are variants made from the same raw materials as Parylene N, except that in Parylene C one aromatic hydrogen atom is replaced with a chlorine atom, and in Parylene D two aromatic hydrogen atoms are replaced with chlorine atoms. In particular, the plastic coating 7 may consist of a fluorinated parylene, and preferably an aliphatic fluorinated parylene. For example, in this derivative, described as Parylene AF4 and commercially available under the trade name Parylene HT, two hydrogen atoms are replaced with two fluorine atoms in the aliphatic carbon bond between benzene rings.

[0066] The production of plastic coatings 7 made of parylene is prior art in itself and therefore does not require further explanation. Typically, parylene coatings are produced by chemical vapor deposition. First, a suitable dimer, such as di-para-xylylene (or a halogenated, e.g., fluorinated, derivative), is evaporated and passed through a high-temperature zone (pyrolysis), which forms a monomer (e.g., para-xylylene). The monomer then polymerizes on the surface to be coated, in this case, on the metal coating 6 surrounding the permanent magnet 21, thereby forming a parylene coating as plastic coating 7.

[0067] In this case, it is also preferred that the plastic coating 7 completely surrounds the metal coating 6 and thus the permanent magnet 21. This means that the plastic coating 7 forms a second covering around the permanent magnet 21, which completely surrounds the metal coating 6. The plastic coating 7 is applied directly onto the metal coating 6. For this purpose, the metal coating 6 is used as a substrate on which the parylene polymer is deposited during the production of the plastic coating 7.

[0068] It is preferable to produce the plastic coating 7 in several successive coating processes, in each of which a parylene layer is deposited on the substrate. For this purpose, the permanent magnet 21 provided with the metal coating 6 is inverted at least once during the coating process so that the contacts on which the permanent magnet 21 rests are also covered during the subsequent coating process. Additionally, a more uniform and dense coating can be produced by the composite coating, and recesses in the permanent magnet 21 or the metal coating 6 can also be uniformly covered. Specifically, at least three coating processes, each producing a parylene layer, are carried out so that the finished plastic coating 7 comprises at least three overlapping parylene layers. The total thickness of the plastic coating 7 is preferably at least 40 micrometers, more preferably at least 60 micrometers, and most preferably about 80 micrometers or more.

[0069] The rotor 1 further comprises a cladding 3 completely enclosing the permanent magnets 21, a metal coating 6 completely enclosing the permanent magnets 21, and a plastic coating 7. The cladding 3 thus forms a completely closed housing for the permanent magnets 21 and the coatings 6 and 7 provided thereon. The cladding 3 comprises a cup-shaped housing part 31 that receives the permanent magnets 21 with the metal coating 6 and the plastic coating 7, and a cover 32 that seals the cup-shaped housing part 31 and is welded to the cup-shaped housing part 31 along a weld seam 33. Infrared welding is preferred for welding the cover 32 to the housing part 31.

[0070] As already mentioned, the covering 3 consists of a thermoplastically processable fluoropolymer, in particular a weldable one. Particularly preferably, the covering 3 consists of PFA. The covering 3 may also preferably consist of ECTFE or PVDF.

[0071] Therefore, non-weldable plastics or non-weldable fluoropolymers such as polytetrafluoroethylene (PTFE), known by the trade name Teflon®, are not particularly suitable for the coating 3. Only weldable or PFA solderable PTFE compounds, which typically contain small amounts of PFA, may be used.

[0072] Of course, the pump housing 101 may also be made of a non-weldable plastic, in particular a non-weldable fluoropolymer such as PTFE.

[0073] The cup-shaped housing part 31 that receives the permanent magnet 21 has a substantially ring-shaped cavity into which the permanent magnet 21 provided with the metal coating 6 and the plastic coating 7 is inserted. The depth T, meaning the extension in the axial direction A, of the cavity 34 is slightly longer than the extension in the axial direction A of the permanent magnet 21 including the metal coating 6 and the plastic coating 7, so that the housing part 31 projects downwardly, as shown in FIGS. 2 and 3, above the permanent magnet 21 and the plastic coating 7 relative to the axial direction A. When the cover 32 is placed on or welded to the housing part 31, an axial gap 81 is present in each case between the metal coating 6 and the plastic coating 7 that surrounds the permanent magnet 21, the cover 32, and the bottom of the cavity 34. The extension of the axial gap 81 in the axial direction A is preferably approximately 0.5 to 1 mm in each case.

[0074] In the radial direction, the cavity 34 has a width B dimensioned such that there is a radial gap 82 between the cladding 3 and the plastic coating 7 surrounding the metal coating 6 and permanent magnet 21. The radial gap 82 typically has a width (radially) of less than 0.5 millimeters, for example about 0.1 mm.

[0075] The cover 32 has a raised portion 321 protruding from the cover 32 in the axial direction A, so that according to the diagram (FIG. 2) an axial air gap 81 is present in each case both above and below the permanent magnet 21 or the plastic coating 7. The metal coating 6 and the plastic coating 7 with the permanent magnet 21 can rest on this raised portion 321, so that the axial air gap 81 is formed laterally adjacent to the raised portion 321. For example, the raised portion 321 can be designed as a ring-shaped raised portion 321, which is arranged coaxially with the set rotation axis and radially centered with respect to the permanent magnet 21.

[0076] Several anti-rotation devices 35 are provided, allowing torque to be transmitted from the permanent magnets 21 to the cladding 3, so that the magnetically effective core 2, in this case the permanent magnets 21, cannot rotate relative to the cladding 3, but instead takes the cladding 3, as well as the vanes 4 and cover plate 5, with it during its rotation. Each anti-rotation device 35 comprises a pin 351 extending in the axial direction A, which is an integral component of the cup-shaped housing part 31 of the cladding 3, and a hole 352 provided in the permanent magnet, into which the respective pin 351 fits. For this purpose, each pin 351 and the respective hole 352 interacting with the pin 351 are designed so that the permanent magnets 21 cannot rotate relative to the cladding 3, but the rotation of the permanent magnets 21 is transmitted to the cladding 3. Both a metal coating 6 and a plastic coating 7 are also provided in each of the holes 352, so that the permanent magnets 21 are completely surrounded by the metal coating 6 and the plastic coating 7. This means that both a metal coating 6 and a plastic coating 7 are provided between each hole 352 and the pin 351 that fits therein.

[0077] As shown in FIG. 3, the metal coating 6 comprises three metal layers, one above the other. The innermost layer 61 is disposed directly on the surface of the permanent magnet 21, the middle layer 62 is disposed directly on the innermost layer 61, and the outermost layer 63 is disposed directly on the middle layer 62. The three layers 61, 62, and 63 are preferably deposited successively by galvanic techniques (electroplating) or currentless metal deposition (chemical vapor deposition without external current). Preferably, the innermost layer 61 and the outermost layer 63 each consist of nickel (Ni). The middle layer preferably consists of copper (Cu), but can alternatively consist of gold (Au) or rhodium (Rh). The total thickness of the metal coating is preferably 30 to 100 micrometers, particularly preferably 50 to 60 micrometers. In this case, the innermost layer 61 has a thickness of approximately 10 to 20 micrometers, the middle layer 62 has a thickness of approximately 10 to 20 micrometers, and the outermost layer 63 has a thickness of approximately 30 micrometers.

[0078] 3, it is of course also possible for the metal coating 6 to consist of only one layer, which is then preferably made of Ni, Au or Rh. It is also possible for the metal coating 6 to consist of two layers, with the inner layer preferably made of Ni and the outer layer made of Au or Rh. Furthermore, the metal coating 6 may comprise more than the three layers 61, 62, 63.

[0079] In order to protect the plastic coating 7 from excessive heat, particularly during welding of the cover 32 to the cup-shaped housing part 31, which may lead to deterioration of the plastic coating 7, a thermal protection film 9 is preferably provided between the cover 32 of the covering 31 and the plastic coating 7. The thermal protection film 9 is preferably a polyimide film, for example one commercially available under the trade name Kapton. The thermal protection film 9 is preferably provided only between the underside of the plastic coating 7 according to the diagrams (FIGS. 2 and 3) and the covering 3, i.e., in the area of ​​the plastic coating 7 closest to the weld seam 33.

[0080] Instead of or in addition to the thermal protection film 9, it is preferred that the plastic coating 7 consists of fluorinated parylene and particularly preferably an aliphatic fluorinated parylene, also designated Parylene AF4. In particular, the aliphatic fluorinated parylene has a particularly high thermal stability.

[0081] In order to avoid temperature-related degradation of the plastic coating 7, particularly when welding the cover 32 to the housing part 31 of the covering material, several variants are preferred: The plastic coating 7 consists of a non-fluorinated parylene, for example Parylene N or Parylene C or Parylene D, and is provided with a thermal protection film 9; or the plastic coating 7 consists of a fluorinated parylene, in particular an aliphatic fluorinated parylene of the Parylene AF4 type, and is not provided with a thermal protection film 9; or the plastic coating 7 consists of a fluorinated parylene, in particular an aliphatic fluorinated parylene of the Parylene AF4 type, and is additionally provided with a thermal protection film 9.

[0082] The rotor 1 is preferably manufactured using the following procedure: First, a metal coating 6 is applied to the ring-shaped permanent magnet 21 so that the permanent magnet is completely surrounded by the metal coating. Subsequently, a plastic coating 7 is deposited from parylene on the metal coating 6 so that the metal coating 6 is completely surrounded by the plastic coating 7. A cup-shaped housing part 31 is then provided. The permanent magnet 21 with the metal coating 6 and the plastic coating 7 is inserted into the ring-shaped cavity 34 of the housing part 31 in such a way that the pin 351 fits into the hole 352. Optionally, a thermal protection film 9 is applied to the surface of the plastic coating 7 facing the cover 32 or to the surface of the cover 32 facing the plastic coating. The cup-shaped housing part 31 with the permanent magnet 21 therein is covered or closed by placing the cover 32. The lid 32 is then welded to the cup-shaped housing part 31 by infrared welding.

[0083] The gaps 81, 82 are also advantageous with regard to welding, since the fluoropolymer that makes up the coating 3 and that is liquefied during welding can migrate into the gaps 81, 82 along the weld seam 33, without the risk of the migrated material damaging the plastic coating 7. The polymer material that migrates during welding is shown in Figure 3 through the bead 36.

[0084] 4 shows a cross-sectional view of a second embodiment of a rotary machine according to the present invention, which has a second embodiment of a rotor according to the present invention. In the following description of the embodiment of the rotary machine and the second embodiment of the rotor, only the differences from the first embodiment of the rotary machine and the first embodiment of the rotor are described. Otherwise, the description of the first embodiment of the rotor or rotary machine is equally or almost equally valid for the second embodiment of the rotor or rotary machine. In the second embodiment of the rotor or rotary machine, the same parts or parts with the same function are provided with the same reference numerals as in the first embodiment of the rotor or rotary machine.

[0085] The second embodiment of the rotary machine according to the invention is also designed as a centrifugal pump 100 comprising a pump housing 101 with an inlet 102 and an outlet 103 for the fluid to be conveyed. A second embodiment of the magnetically levitable rotor 1 according to the invention is arranged inside the pump housing 101. For better understanding, Fig. 5 shows another cross section of the magnetically levitable rotor 1 of Fig. 4, and Fig. 6 shows a cross section through the rotor 1 of Fig. 5 along the section line VI-VI of Fig. 5, i.e. perpendicular to the axial direction A.

[0086] The rotor 1 has a magnetically effective core 2 that includes several permanent magnets 21, namely two permanent magnets 21 in this case, to drive the rotation of the rotor 1 about a set rotation axis that defines the axial direction A. In addition to the two permanent magnets 21, the magnetically effective core 2 includes a base 22 in which the permanent magnets 21 are embedded. The base 22 is made of a soft magnetic material such as iron, nickel-iron, or silicon-iron. The base 22, together with the permanent magnets 21, form the magnetically effective core 2 of the rotor 1. The base 22 and the permanent magnets 21 are designed so that the magnetically effective core 2 has an overall cylindrical shape, with the longitudinal axis of the cylindrical magnetically effective core 2 extending in the axial direction A.

[0087] The base body 22 has a generally cylindrical shape with a ring-shaped recess 221 on the cylindrical shell surface that receives the two permanent magnets 21. The recess 221 is provided in the center of the base body 22 with respect to the axial direction A. Each of the two permanent magnets 21 is designed as a curved segment having the shape of a hollow semi-cylinder, so that the two permanent magnets 21 complement each other to form a substantially hollow cylinder. In this case, the recess 221 in the base body 22 and the two permanent magnets 21 are designed so that the base body 22 and the two permanent magnets 21 complement each other to form a substantially cylindrical magnetically effective core 2.

[0088] In contrast to the first embodiment, which is designed on the principle of a bearingless motor, in a second embodiment of a rotary machine 100 according to the invention, the drive function of the rotor 1 and the magnetic bearing function of the magnetically levitated rotor 1 are separated from each other. To this end, the centrifugal pump 100 has a drive stator 110 (FIG. 4) that drives the rotation of the rotor 1 about the axial direction A, and at least one bearing stator 111, in this case two bearing stators 111, that can magnetically levitate the rotor 1, preferably magnetically and contactlessly relative to the bearing stators 111. All stators 110, 111 are arranged radially outward relative to the pump housing 101 and thus relative to the rotor 1.

[0089] The drive stator 110 surrounds the pump housing 101 in the axial direction A, in which two permanent magnets 21 are arranged in the magnetically effective core 2 of the rotor 1, with which the drive stator 110 also interacts as an electromagnetic rotary drive. For this purpose, the drive stator 110 comprises one or several windings 110a which are able to generate an electromagnetic field, e.g. a rotating field, which drives the rotation of the rotor 1 about the axial direction A in a manner known per se. With regard to the design of the drive stator 110, all known designs are possible. It is only important that the rotation of the rotor 1 about the axial direction A is driven by means of the drive stator 110.

[0090] Two bearing stators 111 for magnetically levitating the rotor 1 are arranged next to the drive stator 110 in the axial direction A, with the bearing stators 111 on either side of the drive stator 110, and the drive stator 110 is arranged between the two bearing stators 111 in the axial direction A. Preferably, the two bearing stators 111 are equidistant from the drive stator 110. Each bearing stator 111 has one or more windings 111a capable of generating an electromagnetic field and magnetically levitating the rotor 1, preferably magnetically contactlessly levitating the rotor 1 relative to the bearing stator 111. In this case, each bearing stator 111 interacts with the magnetically effective core 2 of the rotor 1 according to the principle of magnetic bearings. Such magnetic bearings are known per se in many designs from the prior art and therefore do not require further description here. The specific design of the bearing stators 111 is not essential to the invention. It is only important that the rotor 1 with its bearing stator(s) 111 is magnetically levitable, preferably magnetically contactlessly levitable.

[0091] According to the invention, also in the second embodiment of the rotor 1 according to the invention, the covering 3 consists of a thermoplastically processable, in particular weldable, fluoropolymer which completely surrounds the magnetically effective core 2. Furthermore, each permanent magnet 21 has a metal coating 6, and a plastic coating 7 is provided between the metal coating 6 and the covering 3, which plastic coating likewise consists of a polymer belonging to the parylene family.

[0092] Also in the second embodiment of the rotor 1, the cladding 3 preferably consists of weldable PFA. Alternatively, the cladding 3 is preferably made of ECTFE or PVDF.

[0093] In the second embodiment, the pump housing 101 is also preferably made of a fluoropolymer, but this does not have to be weldable or thermoplastically processable. Of course, it is also possible for the pump housing 101 to be made of the same plastic or polymer as the coating.

[0094] With regard to the design of the metal coating 6 and the plastic coating 7, as well as the suitable materials of these coatings 6, 7, the explanations and definitions relating to the first embodiment are equally or almost equally valid for the second embodiment.

[0095] 5 and 6, the metal coating 6 is provided directly on each permanent magnet 21. In this regard, each permanent magnet 21 is completely surrounded by the metal coating 6 provided directly thereon.

[0096] The plastic coating 7 completely surrounds the magnetically effective core 2. To this end, the plastic coating 7 is provided directly on the surface of the substrate 22, directly on that region of the metal coating 6 which forms part of the outer boundary surface of the magnetically effective core.

[0097] Thus, in manufacturing the rotor 1, the permanent magnets 21 are first provided with a metal coating 6. In this case, the metal coating 6 is deposited on all surfaces of each permanent magnet 21 such that each permanent magnet 21 is completely covered and encapsulated by the metal coating 6. After the permanent magnets 21 are provided with the metal coating 6, they are inserted into recesses 221 in the substrate 22. A plastic coating 7 is then produced over the entire magnetically effective core 2, i.e., over the substrate 22 and permanent magnets 21 having the metal coating 6 thereon, by depositing at least one, and preferably several, layers of parylene that completely surround the magnetically effective core 2.

[0098] Much like in the first embodiment, the covering 3 preferably again comprises several parts, for example two parts, whereby the magnetically effective core 2 provided with the plastic coating 7 is inserted into one of the parts and the two parts are then welded together.

[0099] 7 shows a schematic diagram of a first variant of the second embodiment of the magnetically levitable rotor 1. The blades 4 and cover plate 5 of the rotor 1 are not shown in FIG.

[0100] In this first variant, the plastic coating 7 does not surround the entire magnetically effective core 2 of the rotor 1, but the metal coating 6 only surrounds each of the two permanent magnets 21 provided thereon.

[0101] In this first variant, the permanent magnets 21 are first provided with a metal coating 6. For this purpose, the metal coating 6 is deposited on all surfaces of each permanent magnet 21 so that each permanent magnet 21 is completely covered and encapsulated by the metal coating 6. After the permanent magnets 21 have been provided with the metal coating 6, a plastic coating 7 is produced on each metal coating 6 by depositing at least one, and preferably several, parylene layers, which completely surround the metal coating 6 and the permanent magnets 21 encapsulated thereby.

[0102] The permanent magnet 21 provided with the metal coating 6 and the plastic coating 7 is then inserted into the recess 221 of the base body 22. Then the cladding material 3 is provided, which completely surrounds the magnetically effective core 2 of the rotor 2.

[0103] 8 shows a schematic diagram of a second variant of the second embodiment of the magnetically levitable rotor 1. The blades 4 and cover plate 5 of the rotor 1 are not shown in FIG.

[0104] In a second variant, the entire magnetically effective core 2 is completely surrounded by both the metal coating 6 and the plastic coating 7. In this variant, the metal coating 6 does not directly and completely surround the individual permanent magnets 21, but rather the metal coating 6 is provided directly only on the surfaces of the permanent magnets 21 that form part of the radially outer surface of the magnetically effective core 2.

[0105] In this second variant, the as-yet-uncoated permanent magnet 21 is first inserted into the recess 221 of the base body 22. The entire magnetically effective core 2, i.e., the base body 22 with the permanent magnet 21 inserted therein, is then provided with the metal coating 6. In doing so, the metal coating 6 is deposited on the entire surface of the magnetically effective core 2 so that the magnetically effective core 2 is completely covered and completely surrounded by the metal coating 6. After the magnetically effective core 2 is provided with the metal coating 6, the plastic coating 7 is produced directly on this metal coating 6 by depositing at least one, and preferably several, parylene layers that completely surround the metal coating 6 and the magnetically effective core 2 that is surrounded thereby. The coating 3 is then provided, completely surrounding the magnetically effective core 2 of the rotor 1.

[0106] 9 shows a schematic diagram of a third variant of the second embodiment of the magnetically levitable rotor 1. The blades 4 and cover plate 5 of the rotor 1 are not shown in FIG.

[0107] In a third variant, the metal coating 6 is again applied directly on each permanent magnet 21. In this case, each permanent magnet 21 is completely surrounded by the metal coating 6 applied directly thereon. The plastic coating 7 does not surround the entire magnetically effective core 2 of the rotor 1, but only covers the area of ​​the metal coating 6 of each permanent magnet 21 that forms part of the radially outer surface of the magnetically effective core 2. This means that in each case, only the radially outer surface of the metal coating 6 is covered by the plastic coating 7. Preferably, the plastic coating 7 extends slightly farther in the axial direction A than the metal coating 6, so that the boundary area between the metal coating 6 and the recess 221 of the base 22 is covered and protected against the penetration of acidic or chemically corrosive substances. Therefore, the plastic coating 7 is preferably designed to have a small overlap with the base 22 on both sides in the axial direction A. Parylene penetrates scratches, cracks or gaps very well, ensuring that the permanent magnet 21 in particular is protected against the intrusion of substances into the boundary between the metal coating 6 on the permanent magnet and the recess 221 in the substrate 22.

[0108] In this third variant, the permanent magnets 21 are first each provided with a metal coating 6. In this case, the metal coating 6 is deposited on all surfaces of each permanent magnet 21 so that each permanent magnet 21 is completely covered and encapsulated by the metal coating 6. After the permanent magnets 21 are provided with the metal coating 6, they are inserted into the recesses 221 of the substrate 22. The radially outer surface of each metal coating 6 is then coated with parylene. For this purpose, a plastic coating 7 is produced directly on these surfaces of the metal coating 6 by depositing at least one, preferably several, parylene layers, the plastic coating 7 being manufactured so that it slightly overlaps the substrate 22 on both sides in the axial direction A. This can be achieved, for example, by covering or masking the areas of the substrate 22 that will not be covered during the deposition of the parylene layers.

[0109] After completion of the plastic coating 7, the cladding 3 is provided which completely surrounds the magnetically effective core 2 of the rotor 1.

[0110] The magnetically levitable rotor 1 according to the invention and the rotary machine 100 according to the invention are particularly suitable for the semiconductor industry, especially for the manufacturing process of semiconductors or semiconductor chips, in particular in the design as centrifugal pumps or mixers. [Explanation of symbols]

[0111] 1 rotor 2 cores 3 Covering material 4 Feathers 5 cover plate 6 Metallic Coating 7. Plastic Coating 9. Heat protection film 21 Permanent magnets 22 Base 31 Cup-shaped housing part 32 Cover, lid 33 Welded seam 34 Cavity 35 Anti-rotation device 36 Bead 61 innermost layer 62 Middle Class 63 Outermost layer 81 Axial gap 82 Radial voids 100 Centrifugal pumps, rotating machines 101 Pump housing 102 Entrance 103 Exit 104 Stator 105 Coil Core 106, 110a, 111a windings 107 Termination part 110 Drive stator 111 Bearing stator 221 recess 321 Ridge 351 pins 352 holes A axis direction B Width T Depth

Claims

1. 1. A rotor for a rotary machine having a magnetically levitated rotor, the rotor being capable of magnetic levitation, the rotor having a magnetically effective core (2) and a covering (3) made of a thermoplastic fluoropolymer, the covering (3) completely surrounding the magnetically effective core (2), the magnetically effective core (2) comprising at least one permanent magnet (21), each permanent magnet (21) having a metallic coating (6) for protection against acidic or chemically corrosive substances, a plastic coating (7) provided between the metallic coating (6) and the covering (3), the plastic coating (7) consisting of a polymer belonging to the fluorinated parylene family, preferably consisting of aromatic fluorinated variants such as Parylene HT, Parylene AF4 and Parylene VT4.

2. 2. A rotor according to claim 1, wherein the metallic coating (6) comprises at least one layer (61, 62, 63) of nickel or gold or rhodium.

3. 3. The rotor according to claim 1, wherein the metallic coating (6) comprises at least three layers (61, 62, 63) arranged one above the other, the innermost layer (61) being provided directly on the surface of the permanent magnet (21) and made of nickel.

4. 4. A rotor according to claim 3, wherein the metallic coating (6) comprises exactly three layers (61, 62, 63) arranged one above the other, the innermost and outermost layers (61, 62, 63) each consisting of nickel, and the intermediate layer (62) therebetween consisting of copper, gold or rhodium.

5. A rotor according to any one of claims 1 to 4, wherein the coating (3) consists of a perfluoroalkoxy polymer, ethylene chlorotrifluoroethylene or polyvinylidene fluoride.

6. 6. A rotor according to any one of claims 1 to 5, wherein a thermal protection film (9) is provided between the plastic coating (7) and the covering material (3), the thermal protection film being a polyimide film.

7. A rotor according to any one of claims 1 to 6, wherein the plastic coating (7) consists of fluorinated parylene.

8. A rotor according to any one of claims 1 to 7, wherein the metallic coating (6) completely surrounds the magnetically effective core (2).

9. A rotor according to any one of claims 1 to 8, wherein the plastic coating (7) completely surrounds the magnetically effective core (2).

10. 10. A rotor according to any one of claims 1 to 9, wherein the metal coating (6) is provided directly on each permanent magnet (21), and each permanent magnet (21) is completely surrounded by the metal coating (6) provided directly thereon.

11. 11. A rotor according to claim 10, wherein the plastic coatings (7) are applied directly onto the metal coatings (6), each metal coating (6) being completely surrounded by the plastic coating (7) applied directly thereon.

12. A rotor according to any one of claims 1 to 11, wherein the magnetically effective core (2) consists of permanent magnets (21), said permanent magnets (21) being designed integrally in the form of a ring.

13. 13. A rotor according to any one of claims 1 to 12, wherein the covering (3) comprises a cup-shaped housing part (31) that receives the magnetically effective core (2) and a cover (32) that is welded to the cup-shaped housing part (31), and the cup-shaped housing part (31) is designed so that an air gap (81, 82) exists between the magnetically effective core (2) and the cup-shaped housing part (31).

14. 14. A rotary machine for influencing a fluid, comprising a magnetically levitable rotor (1) and a stator (104, 110), whereby the rotor (1) can be magnetically driven in a contactless manner to rotate about an axial direction (A) in an operating state, characterized in that the rotor (1) is magnetically levitated and is designed according to any one of claims 1 to 13.

15. 15. The rotary machine according to claim 14, which is designed as a bearingless motor, and the stator is designed as a bearing stator and a drive stator (104), whereby the rotor (1) can be driven magnetically without contact in an operating state, and whereby the rotor (1) can be levitated magnetically without contact at least in a radial direction relative to the stator (104).

16. The rotary machine according to claim 14 or 15, wherein the rotary machine is a centrifugal pump or a mixing device.

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