Magnetically levitated rotor and rotary machine having 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 categories. [Background technology]

[0002] Rotating machines with magnetically levitated rotors, for example centrifugal pumps or mixers or agitators, are used in many technical fields, in particular for applications where high purity fluids are conveyed, stirred or mixed without contaminating the fluid with wear particles from the machine 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 no metal ions reach the liquid from the magnetically levitated rotor, since such metal ions can change the doping of the semiconductor.

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

[0004] However, designs of rotating machines with a magnetically non-contact suspended rotor are also known, in which no separate magnetic bearing is provided, and the bearing and drive functions are realized by the same stator. The term "bearingless motor" has been established for such designs, since no separate magnetic bearing is provided on the rotor. The bearing and drive functions cannot be separated from one another. These particularly efficient bearingless motors are characterized in particular by a very compact design and the simultaneous realization of the "non-contact" concept.

[0005] Thus, a bearingless motor is an electromagnetic rotary drive in which the rotor is fully magnetically suspended relative to the stator and is not provided with a separate magnetic bearing. For this purpose, the stator is designed as 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 by means of 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] The rotor of a rotating machine, especially when designed as a pump, mixer or agitator, is often a one-piece rotor, which is both the rotor of the electromagnetic drive and the rotor of the pump or mixer, thereby influencing the fluid.

[0007] Different concepts are known for the design of the rotor's magnetically effective core. For example, the rotor's magnetically effective core can consist of only one or more permanent magnets, so that the entire rotor's magnetically effective core is made of permanent magnet 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 for example a centrifugal pump, is designed with separate 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, in particular the permanent magnets, are also protected from such corrosive substances. The materials normally used for permanent magnets, such as for example 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 transported in semiconductor manufacturing are often treated with ozone, for example, water (O 3 , H 2 O), sulfuric acid (H 2 SO 4 ), phosphoric acid (H 3 PO 4 ), hydrochloric acid (HCl), hydrofluoric acid (HF), nitric acid (HNO 3 ), ozone (O 3 ) or for example sulfuric acid (H 2 SO 4 ) and hydrogen peroxide (H 2 O 2 ) or sulfuric acid (H 2 SO 4 ) and nitric acid (HNO 3 To make matters worse, these corrosive materials often must be provided at high temperatures, e.g., 150° C. to 200° C. or even higher.

[0010] To protect against such corrosive substances, it is known to provide the magnetically active core of the rotor, in particular the permanent magnets or magnets, with a plastic coating of fluorohydrocarbons, 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, encapsulation from fluorocarbons can be difficult due to, for example, significant amounts of sulfuric acid and ozone (O 3 H with 2 SO4 Ozone (O 3 ), and studies have shown that corrosion occurs despite these 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 metallic coating, and even chipping of parts 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 2 549 113 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 against acids, usually liquids, and the inner metallic covering protects the magnetically effective core against gaseous components that are relatively capable of penetrating the plastic covering.

[0014] Although the concept of double cladding has proven itself in practice, there is still a need for improvement. On the one hand, the thick metal cladding of the rotor permanent magnets proposed in EP 2549113 is relatively difficult to realize, since the welding of the individual parts of the cladding must be gas-tight, but on the other hand, the energy input during welding must be kept low enough so that the structure of the permanent magnet material is not changed. This problem is complicated by the fact that the metal cladding must be relatively close to the permanent magnets, since the magnetic air gap cannot be increased during magnetic levitation without too much loss of force. 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 metal cladding is corroded, metal ions can diffuse through the plastic cladding into the fluid being transported and contaminate the fluid. In semiconductor industry applications, such metal ions in fluids can have extremely negative consequences, since even very small concentrations of dissolved metal ions can, for example, alter the doping of the semiconductor structures being processed in an uncontrolled manner and, in the worst case, render the semiconductor products unusable.

[0015] Therefore, great efforts have been made to better protect the magnetically active core of the rotor against acids or other chemically corrosive substances and at the same time to avoid the above-mentioned problems in welding the metal cladding of the permanent magnets. For this purpose, a wide variety of metal layers have been electrochemically applied to the permanent magnets and their corrosion resistance has been tested. However, even electrochemically applied metal cladding, for example with gold or rhodium, which are considered to be very inert, surprisingly did not lead to really 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, e.g. hydrochloric acid (HCl) or hydrofluoric acid (HF) or ozone (O3), can diffuse into the coating through lattice or microstructural defects in the metal layer, e.g. 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 rotating 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 rotating machine having such a rotor. [Means for solving the problem]

[0020] The object of the invention to solve this problem is characterized by the features of the independent claims of the respective categories.

[0021] According to the invention, for a rotating machine having a magnetically levitated rotor, a magnetically levitable rotor is proposed, which has 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 is provided between the metal coating and the covering, the plastic coating consisting of a polymer belonging to the parylene family.

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

[0023] Very complex and extensive research has shown that this exact combination of a metallic coating of the permanent magnet, directly bonded to the permanent magnet, with an outer cladding of fluoropolymer and a Parylene coating in between, ensures a particularly good and long-lasting protection of the magnetically effective core of the rotor against acids, acidic fluids and other chemically corrosive substances, such as, for example, ozone or hydrogen. The magnetically effective core of the rotor is protected by this special combination against both corrosive liquid components, such as, for example, liquid acids, and against gaseous components. In particular, the magnetically effective core of the rotor or the permanent magnets is protected against the application of, for example, hydrogen (H 2 ), ozone (O 3 The diffusion of substances with very small molecules, such as fluorine (HF), hydrochloric acid (HCl), etc., is also prevented or at least significantly reduced. Compared to the fluoropolymers of the outer coating, the polymer chains of parylenes are significantly longer, which makes them 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-xylylene (xylylene is also called xylene or dimethylbenzene) or its halogenated derivatives. Different parylenes are distinguished depending on which substituents are attached to the benzene ring. In the basic product poly-p-xylylene, known as Parylene N, the benzene ring has only aromatic hydrogen atoms, i.e. each of the four radicals of the benzene ring is a hydrogen atom. In addition, other commercial products are specifically Parylene C, Parylene D, and Parylene HT. In Parylene C, one of the aromatic hydrogen atoms is replaced by a chlorine atom, in Parylene D, two of the aromatic hydrogen atoms are replaced by one chlorine atom each, and Parylene HT is a halogenated derivative in which the alpha hydrogen atoms of the dimer are each replaced by a fluorine atom.

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

[0026] It has proven to be 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 if the metal coating comprises several, in particular at least three, coatings arranged one above the other, with the innermost layer being applied directly on the surface of the permanent magnet and preferably consisting of nickel. Nickel is particularly preferred, since it adheres well to NdFeB-based alloys as well as to SmCo-based alloys. Nickel is also preferred as the outermost metal layer, since parylene also adheres better to nickel, in particular than to precious metals such as gold or rhodium.

[0028] In a preferred embodiment, the metallic 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 a multi-layer metal coating, the innermost layer is applied first to the surface of the permanent magnet. An intermediate layer is then 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 deposition (chemical vapor deposition without external electric 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 towards 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 between 30 and 100 micrometers, particularly preferably between 50 and 60 micrometers.

[0032] As regards the coating, it is preferred that the coating 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 the manufacture of rotors.

[0033] The fluoropolymer coating preferably comprises at least two parts welded together, infrared welding being preferred for this purpose. In order to protect the plastic coating made of parylene from excessive heat input, especially during the welding process, it is advantageous for a heat protection film, preferably a polyimide film, to be provided between the plastic coating and the coating. For this purpose, for example, materials available under the trade name Kapton are suitable.

[0034] According to a preferred embodiment, the plastic coating consists of fluorinated parylene, preferably aliphatic fluorinated parylene. In particular, two variants of fluorinated parylene are currently commercially available, namely 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 by two fluorine atoms. For this purpose, the alpha hydrogen atom of the dimer is replaced by a fluorine atom to produce parylene. In the aromatic fluorinated variant, the aromatic hydrogen atoms are each replaced by a fluorine atom, i.e. each of the four radicals of 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 of up to 450° C. without degradation, at least for a short period of time. Of course, when using fluorinated parylene, a polyimide thermal protection film can be provided between the plastic coating of parylene and the covering material.

[0036] Preferably, the metal coating completely surrounds the magnetically effective core, i.e. the entire magnetically effective core is completely surrounded by the metal 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 metal coating, such that the entire permanent magnet is completely covered by the metal coating, i.e. completely surrounded or encapsulated by the metal coating.

[0037] It is also preferred that the plastic covering completely surrounds 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 disposed directly on each permanent magnet, such that each permanent magnet is completely surrounded by the metal coating disposed directly thereon.

[0039] Moreover, 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 for receiving the magnetically effective core and a cover welded to the housing part, the cup-shaped housing part being preferably designed in such a way 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. The air gap is also provided in the axial direction, i.e. at the bottom or cover of the cup-shaped housing part, and has a width in the axial direction of about 0.5 to 1 mm.

[0042] Furthermore, the present invention proposes a fluid-influencing rotating machine, in particular a centrifugal pump or mixer, having a magnetically levitable rotor and stator, whereby the rotor can be magnetically driven in a non-contact manner to rotate around an axial direction in the 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 contactlessly in the operating state and can be suspended magnetically contactlessly 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 description 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; [Diagram 2] FIG. 2 is a cross-sectional view of the magnetically levitable rotor of FIG. 1. [Diagram 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. [Diagram 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 PREFERRED EMBODIMENTS

[0047] Figure 1 shows in a first cross-sectional view a first embodiment of a rotary machine according to the invention, with a first embodiment of a rotor according to the invention. Here, the rotary machine is designed as a centrifugal pump and is given the overall reference 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 are sulfuric acid (H 2 SO 4 ), phosphoric acid (H 3 PO 4 ), hydrochloric acid (HCl), hydrofluoric acid (HF), nitric acid (HNO 3 ), ozone (O 3 ), or for example sulfuric acid (H 2 SO 4 ) and hydrogen peroxide (H 2 O 2 ) or sulfuric acid (H 2 SO 4 ) and nitric acid (HNO 3 ) may be included.

[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 arranged in the pump housing 101, said rotor being generally designated by the reference number 1. For better understanding, 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 radial.

[0049] In a first embodiment, the magnetically effective core 2 consists only of a permanent magnet 21, which is here designed 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 the operating state, the ring-shaped permanent magnet 21 is arranged to extend around a set axis of rotation.

[0050] The rotor 1 further comprises a cladding 3 made of a thermoplastically processable fluoropolymer, which completely surrounds the magnetically effective core 2 such that the latter is completely embedded in and encapsulated by the cladding 3. The cladding 3 consists of a perfluoroalkoxy polymer (PFA). Alternatively, the cladding 3 can consist of ethylene chlorotrifluoroethylene (ECTFE) or polyvinylidene fluoride (PVDF). The cladding 3 is provided with a number of vanes 4, by means of which the 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 the face facing away from the cladding 3. The pump housing 101 is preferably made of plastic. This may be the same plastic from which the cladding 3 is made or a different plastic. The pump housing 101 preferably consists, at least essentially, of a fluoropolymer. Plastics or polymers which are not thermoplastically processable, i.e. which cannot be welded or injection molded, are also suitable for the pump housing 101, in particular fluoropolymers.

[0051] The pump housing 101 is designed to be insertable into the stator 104, so that the rotor 1 can be magnetically contactlessly driven to rotate about an axial direction A and can be magnetically contactlessly suspended 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 comprises, 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 contactlessly in the operating state. 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 driving stator 104, by means of which the rotor 1 can be driven magnetically contactlessly in the operating state and can be magnetically levitated without contact with respect to the stator 104. The stator 104 and the rotor 1 thus form an electromagnetic rotary drive, which is preferably designed according to the principle of a bearingless motor.

[0053] In the bearingless motor, the rotor 1 can be driven magnetically without contact and can be suspended magnetically without contact with respect to the stator 104. For this purpose, the stator 104 is designed as a bearing stator and a driving stator 104, by means of which the rotor 1 can be driven magnetically without contact about a set axis of rotation, i.e. it can rotate and be suspended magnetically without contact with respect to the stator 104.

[0054] Bearingless motors are well known to those skilled in the art, so that a detailed description of their functioning is no longer necessary. The term bearingless motor refers to the fact that the rotor 1 is fully magnetically suspended and is not provided with a separate magnetic bearing. For this purpose, the stator 104 is designed as 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 comprises windings 106, by which a magnetic rotating field is generated, which 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 the 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 and 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 with respect to a radial plane perpendicular to the set axis of rotation.

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

[0056] In order 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, such 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 inner rotor principle.

[0057] In the embodiment described herein, the centrifugal pump 100, and 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 with 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 inwards to form stator poles. All first ends of the longitudinal legs (which are the lower ends according to the illustration in FIG. 1) are connected to each other by a termination 107. The termination 107 comprises several segments, each of which connects a first end of a coil core 105 to a first end of an adjacent coil core 105. The individual coil cores 105 are preferably arranged such that they are arranged equidistantly on a circular circumference surrounding the rotor 1. During operation, the rotor 1 is levitated in a magnetically contactless manner between the stator poles pointing radially inwards. The magnetically effective core 2 of the rotor is at the same height as the stator poles with respect to 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 thus arranged according to the figure below and outside the magnetic rotor plane. The magnetic rotor plane is the magnetic central 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 the magnetically effective core 2 of the rotor 1 is levitated in the operating state when the rotor 1 is not tilted. In general, the magnetic rotor plane is the geometric central plane of the magnetically effective core 2 of the rotor 1, perpendicular to the axial direction A.

[0059] Preferably, the windings 106 are arranged completely below the magnetically effective core 2. The windings 106 are therefore not arranged in the plane in which the rotor 1 is driven or levitated in the operating state. In contrast to other electromagnetic rotary drives in which the windings of the stator are arranged such that the 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 such 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: 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 an axial direction in the operating state.

[0061] The rotor 1 will now be explained 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, for example, a samarium-cobalt (SmCo) alloy.

[0063] The permanent magnet 21 has a metal coating 6 which serves as a protection against gaseous components, in particular acidic or chemically corrosive substances, and prevents or at least significantly reduces as much as possible the diffusion of such components into the permanent magnet. The metal coating 6, which will be explained in more detail below, is provided directly on the surface of the permanent magnet 21, such 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 of 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 on each surface of the permanent magnet 21 by galvanic techniques (electroplating) or by currentless metal deposition (chemical vapor deposition without an external electric current).

[0065] The plastic coating 7 is applied directly on the metal coating 6, this plastic coating being made of a polymer belonging to the Parylene family. These Parylenes, marketed 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 material as Parylene N, but in Parylene C one of the aromatic hydrogen atoms is replaced by a chlorine atom, and in Parylene D two of the aromatic hydrogen atoms are replaced by chlorine atoms, respectively. In particular, the plastic coating 7 may be made of a fluorinated parylene, and preferably an aliphatic fluorinated parylene. For example, in this derivative described as Parylene AF4 and marketed under the trade name Parylene HT, two hydrogen atoms are replaced by two fluorine atoms in an aliphatic carbon bond between benzene rings.

[0066] The production of a plastic coating 7 made of parylene is prior art per se and therefore does not require further explanation. Typically, a parylene coating is 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, which forms 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 provided directly on 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 preferred 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 during the coating process are also covered during the subsequent coating process. In addition, a more uniform and dense coating can be produced by composite coating, and recesses of the permanent magnet 21 or the metal coating 6 can also be uniformly covered. In particular, at least three coating processes are carried out, in each of which a parylene layer is produced, so that the finished plastic coating 7 comprises at least three overlapping parylenes. The total thickness of the plastic coating 7 is preferably at least 40 micrometers, more preferably at least 60 micrometers, most preferably about 80 micrometers or more.

[0069] The rotor 1 further comprises a covering 3 completely enclosing the permanent magnets 21, a metal coating 6 completely enclosing the permanent magnets 21, and a plastic coating 7. The covering 3 thus forms a completely closed housing for the permanent magnets 21 and the coatings 6 and 7 provided thereon. The covering 3 comprises a cup-shaped housing part 31 receiving the permanent magnets 21 with the metal coating 6 and the plastic coating 7, and a cover 32 sealing the cup-shaped housing part 31 and being 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 coating 3 consists of a thermoplastically processable fluoropolymer, in particular a weldable one. Particularly preferably, the coating 3 consists of PFA. The coating 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 usually contain small amounts of PFA, may be used.

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

[0073] The cup-shaped housing part 31 receiving the permanent magnet 21 comprises 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 of the permanent magnet 21 including the metal coating 6 and the plastic coating 7 in the axial direction A, such that the housing part 31 projects in the axial direction A above the permanent magnet 21 and the plastic coating 7 in the downward direction as shown in Figures 2 and 3. When the cover 32 is placed on the housing part 31 or welded to it, there is in each case an axial gap 81 between the metal coating 6 and the plastic coating 7 surrounding the permanent magnet 21, and between the cover 32 and the bottom of the cavity 34. The extension of the axial gap 81 in the axial direction A is preferably in each case about 0.5 mm to 1 mm.

[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 the permanent magnet 21. The radial gap 82 typically has a width (radial) of less than 0.5 millimeters, for example about 0.1 mm.

[0075] The cover 32 has a ridge 321 which projects from the cover 32 in the axial direction A, such that according to the diagram (FIG. 2) an axial gap 81 is 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 be supported on this ridge 321, such that the axial gap 81 is formed laterally adjacent to the ridge 321. For example, the ridge 321 can be designed as a ring-shaped ridge 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, by means of which torque can be transferred from the permanent magnets 21 to the cladding 3, such that the magnetically effective core 2, in this case the permanent magnets 21, cannot rotate relative to the cladding 3, but instead takes with it the cladding 3 as well as the vanes 4 and the cover plate 5 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 such that the permanent magnets 21 cannot rotate relative to the cladding 3, but the rotation of the permanent magnets 21 is transferred to the cladding 3. Both the metal coating 6 and the plastic coating 7 are also provided in each of the holes 352, such that the permanent magnets 21 are completely surrounded by the metal coating 6 and the plastic coating 7. This means that both the metal coating 6 and the plastic coating 7 are provided between each hole 352 and the pin 351 which fits therein.

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

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

[0079] In order to protect the plastic coating 7 from excessive heat, in particular 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 3 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 figures (FIGS. 2, 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 a preferred measure for the plastic coating 7 to consist 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, in particular 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] To manufacture the rotor 1, the following procedure is preferred: first, the metal coating 6 is applied to the ring-shaped permanent magnet 21, such that the permanent magnet is completely surrounded by the metal coating. Subsequently, the plastic coating 7 is deposited from parylene on the metal coating 6, such that the metal coating 6 is completely surrounded by the plastic coating 7. Then, the cup-shaped housing part 31 is provided. The permanent magnet 21 provided 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 placed on the surface of the plastic coating 7 facing the cover 32 or on the surface of the cover 32 facing the plastic coating. The cup-shaped housing part 31 with the permanent magnet 21 inside 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 constituting the coating 3, which is liquefied during welding, can migrate into the gaps 81, 82 along the weld seam 33, so that there is no risk of the plastic coating 7 being damaged by the migrated material. The polymer material migrated during welding is shown in FIG. 3 through the bead 36.

[0084] 4 shows a cross-sectional view of a second embodiment of a rotary machine according to the invention, with a second embodiment of a rotor according to the invention. In the following description of the rotary machine embodiment 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 signs as in the first embodiment of the rotor or rotary machine.

[0085] A second embodiment of the rotary machine according to the invention is also designed as a centrifugal pump 100 with a pump housing 101 having 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 with several permanent magnets 21, namely here two permanent magnets 21, in order to drive the rotation of the rotor 1 around a set axis of rotation defining an axial direction A. In addition to the two permanent magnets 21, the magnetically effective core 2 comprises a base 22 in which the permanent magnets 21 are embedded. The base 22 consists 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 such 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 substantially cylindrical shape with a ring-shaped recess 221 on the cylindrical shell surface which receives the two permanent magnets 21. With respect to the axial direction A, the recess 221 is provided in the center of the base body 22. Each of the two permanent magnets 21 is designed as a curved segment having the shape of a hollow semi-cylinder, such 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 such 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. For this purpose, the centrifugal pump 100 has a drive stator 110 (FIG. 4) which 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, which can magnetically levitate the rotor 1, preferably in a magnetically contactless manner with respect to the bearing stator 111. All stators 110, 111 are arranged radially outward with respect to the pump housing 101 and thus with respect 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, for example a rotating field, which drives the rotation of the rotor 1 about the axial direction A in a manner known per se. As regards 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 the magnetic levitation of the rotor 1 are arranged next to the drive stator 110 in the axial direction A, the bearing stators 111 being provided on both sides of the drive stator 110, such that the drive stator 110 is arranged between the two bearing stators 111 in the axial direction A. Preferably, the two bearing stators 111 have the same distance from the drive stator 110. Each bearing stator 111 comprises one or more windings 111a capable of generating an electromagnetic field and capable of magnetically levitating the rotor 1, preferably magnetically contactlessly levitating it with respect to the bearing stator 111. In this case, each bearing stator 111 interacts with a 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 according to the prior art and do not require further explanation here. The specific design of the bearing stators 111 is not essential for the invention. It is only important that the rotor 1 with the bearing stator or stators 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, a plastic coating 7 being 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 also preferably consists 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 consist 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 substantially equally valid for the second embodiment.

[0095] As shown particularly in Figures 5 and 6, the metal coating 6 is provided directly on each permanent magnet 21. In so doing, each permanent magnet 21 is completely surrounded by the metal coating 6 provided directly thereon.

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

[0097] Thus, in the manufacture of 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 have been 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 with the metal coating 6 thereon and the permanent magnets 21, 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 then the two parts are welded together.

[0099] 7 shows a schematic diagram of a first variant of the second embodiment of a magnetically levitable rotor 1. The blades 4 and the 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 such 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 thus surrounded.

[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 covering 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 the 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 metallic coating 6 and the plastic coating 7. In this variant, the metallic coating 6 does not directly and completely surround the individual permanent magnets 21, but only those surfaces of the permanent magnets 21 which form part of the radially outer surface of the magnetically effective core 2 are provided with the metallic coating 6 directly.

[0105] In this second variant, the permanent magnet 21, not yet coated, is first inserted into the recess 221 of the substrate 22. The entire magnetically effective core 2, i.e. the substrate 22 with the permanent magnet 21 inserted therein, is then provided with a metal coating 6. In so doing, the metal coating 6 is deposited on the entire surface of the magnetically effective core 2 such that it is completely coated and completely surrounded by the metal coating 6. After the magnetically effective core 2 has been provided with the metal coating 6, a plastic coating 7 is produced directly on this metal coating 6 by depositing at least one, preferably several, parylene layers, completely surrounding the metal coating 6 and the magnetically effective core 2 surrounded thereby. A 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 the cover plate 5 of the rotor 1 are not shown in FIG.

[0107] In a third variant, the metal coating 6 is still applied directly on each permanent magnet 21. In this case, each permanent magnet 21 is completely surrounded by the metal coating 6 applied directly on it. 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. The plastic coating 7 preferably extends slightly further 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 substrate 22 is covered and protected against the ingress of acidic or chemically corrosive substances. The plastic coating 7 is therefore preferably designed to have a small overlap with the substrate 22 on both sides in the axial direction A. Parylene penetrates very well into scratches, cracks or gaps, ensuring that in particular the permanent magnet 21 is protected against ingress of materials, particularly into the interface between the metal coating 6 on the permanent magnet and the recess 221 of 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 such 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, they are inserted into 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, and preferably several, parylene layers, which are manufactured such that they slightly overlap the substrate 22 on both sides with respect to the axial direction A. This can be achieved, for example, by covering or masking the areas of the substrate 22 that are not to be covered during the deposition of the parylene layers.

[0109] After completion of the plastic coating 7, the covering 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 thus 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. Feather 5 Cover Plate 6 Metal 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 gap 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 rotating 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 metal coating (6) for protection against acidic or chemically corrosive substances, and a plastic coating (7) provided between the metal coating (6) and the covering (3), the plastic coating (7) being made of a polymer belonging to the parylene family.

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. A rotor according to claim 1 or 2, 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 consisting 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 layer (61) and the outermost layer (63) each consisting of nickel, and the intermediate layer (62) in between consisting of copper or gold or rhodium.

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

6. A rotor according to any one of the preceding claims, characterized in that 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. A rotor as claimed in any one of claims 1 to 9, wherein the metallic coating (6) is provided directly on each permanent magnet (21), each permanent magnet (21) being completely surrounded by the metallic coating (6) provided directly thereon.

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 onto it.

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

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), the cup-shaped housing part (31) being designed such that there is an air gap (81, 82) between the magnetically effective core (2) and the cup-shaped housing part (31).

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 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, the stator being designed as a bearing stator and a drive stator (104), whereby the rotor (1) can be driven in an operating state in a magnetically contactless manner, whereby the rotor (1) can be levitated in at least a radial direction relative to the stator (104) in a magnetically contactless manner.

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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