Vacuum pump and method for manufacturing a stator portion for a vacuum pump stator

Abstract

To enable a rotor of a pump to be operated at a lower rotor temperature under the same condition in other respects by improving cooling of a vacuum pump, especially a turbo molecular pump in the simplest form.SOLUTION: A vacuum pump, especially a turbo molecular pump, includes a housing and at least one pump stage arranged in the housing. The pump stage includes a stator and a rotor that interacts with the stator to demonstrate a pumping action, which rotates around a rotation axis relatively with respect to the stator when operated. The stator includes at least one stator component with a surface having a first part and a second part different from the first part. The second part of the surface is not coated and has thermal emissivity ε of 0.25, preferably at least 0.3, at 50°C.SELECTED DRAWING: Figure 6b

Description

[Technical Field]

[0001] The present invention relates to a vacuum pump, in particular a turbomolecular pump, comprising a housing and at least one pump stage arranged within the housing, the pump stage having a stator and a rotor which rotates relative to the stator about a rotation axis during operation and interacts with the stator to provide a pumping action.Furthermore, the present invention relates to a method for manufacturing a stator component for a vacuum pump, in particular a turbomolecular pump stator. [Background technology]

[0002] Depending on the type and amount of gas being pumped, rotor heating occurs during operation of vacuum pumps, particularly turbomolecular pumps (TMPs). In many vacuum applications, pumping large amounts of gas causes vacuum pumps, particularly turbomolecular pumps, to operate at their limits because the rotor reaches the maximum temperature at which it can reliably be subjected to sustained loads. Rotor heating can adversely affect the rotor's service life and limit the maximum amount of gas that can be pumped by the vacuum pump.

[0003] In principle, the generated heat can be dissipated by thermal radiation from the rotor to the stator and from there to the outside (possibly cooled) pump housing. However, to improve heat transfer from the rotor to the stator components, the temperature difference between the involved surfaces must be large. Therefore, the surface temperature of the stator components must be as low as possible compared to the surface temperature of the rotor. According to the physical relationship of thermal radiation, an object can absorb or emit heat better the higher the thermal emissivity ε of its surface, i.e., the ratio of its actual radiant power to the radiation of an ideal black.

[0004] The prior art has proposed coating the surfaces of parts of stators. EP 2 775 148 B1 discloses a stator component whose surface is partially coated with a nickel oxide or aluminum oxide layer, which is intended to ensure increased heat transfer across the stator. However, to achieve the necessary dimensional accuracy for certain surfaces of the stator, such as the outer contact surface or the web tips directly facing the rotor adjacent to the radial gap, the oxide layer must either be removed from the stator component after application, or the corresponding surface area must be protected by masking before application. In either case, the method is complicated because, in addition to the necessary steps of forming and post-processing the stator component, both the coating process and a separate step for locally removing or isolating the coating material must be performed. Furthermore, the coating may peel off from the underlying material over time, which can lead to poor emissivity and contamination of the pump with flaked particles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] European Patent No. 2775148 Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is therefore to improve the cooling of vacuum pumps, in particular turbomolecular pumps, as simply as possible, so that the rotor of the pump can be operated at a lower rotor temperature under otherwise identical conditions. [Means for solving the problem]

[0007] This problem is solved by a vacuum pump according to claim 1.

[0008] Such a vacuum pump, in particular a turbomolecular pump, comprises a housing and at least one pump stage arranged in the housing, the pump stage having a stator and a rotor which rotates about a rotation axis relative to the stator during operation and interacts with the stator to produce a pumping action, the stator having at least one stator part with a surface having a first portion and a second portion different from the first portion.

[0009] In this case, according to the invention, the second part of the surface of the stator component is uncoated and has a thermal emissivity ε of at least 0.25, preferably at least 0.3, at 50°C. A high emissivity at 50°C is advantageous, since this temperature is within the range of the rotor's normal operating temperature. Thus, particularly effective heat dissipation occurs during operation.

[0010] The thermal emissivity ε of the second portion of the surface at 50°C is preferably at least 0.4, more preferably at least 0.5, particularly preferably at least 0.6, even more particularly preferably at least 0.7, even more particularly preferably at least 0.8 and most preferably at least 0.9.

[0011] In particular, the thermal emissivity ε of the second portion may be higher than the thermal emissivity of the first portion.

[0012] The thermal emissivity ε is the total emissivity over the infrared wavelength range from 0.78 μm to 1 mm.

[0013] The thermal emissivity ε of a heated object can be measured using a thermal sensor with adjustable emissivity and an infrared measuring instrument. In this case, the actual surface temperature of the heated object is first determined at one point using a contact thermal sensor. The surface temperature is then measured using an infrared measuring instrument, first with an adjusted emissivity of 1. The emissivity of the infrared measuring instrument is then changed until the output temperatures of the thermal sensor and the infrared measuring instrument match. This allows the actual thermal emissivity of the heated object to be experimentally determined.

[0014] Alternatively, the aforementioned problem is solved by the features of claim 2.

[0015] According to the invention, in this alternative, the second portion of the surface of the stator component has surface properties resulting from manufacturing that are not altered by subsequent processing by separation or coating.

[0016] Preferably, the second portion of the surface of the stator component has a manufacturing-induced surface characteristic with a roughness and / or coloration in the range of 3 μm or more, preferably 5 μm or more, more preferably 10 μm or more, even more preferably 20 μm or more, particularly preferably 30 μm, yet particularly preferably 40 μm or more, most preferably 50 μm or more, in particular the coloration being obtained by adding at least one colorant to the starting material used in manufacturing the stator component.

[0017] In order to simultaneously achieve the best possible vacuum-technical properties of the stator component, the roughness of the second portion of the surface of the stator component is furthermore preferably 500 μm or less, more preferably 400 μm or less, even more preferably 300 μm or less, particularly preferably 250 μm or less, very particularly preferably 200 μm or less, very particularly preferably 150 μm or less, and most particularly preferably 100 μm or less. For example, the roughness of the second portion of the surface of the stator component is preferably in the range from 3 μm to 500 μm, more preferably 5 μm to 400 μm, even more preferably 10 μm to 300 μm, very particularly preferably 20 μm to 250 μm, very particularly preferably 30 μm to 200 μm, very particularly preferably 40 μm to 150 μm, and most preferably 50 μm to 100 μm. However, it is understood that any other combination of the aforementioned preferred upper and lower limits not explicitly mentioned herein is also contemplated and also represents a preferred roughness range.

[0018] In another alternative embodiment of the invention, the aforementioned problem is solved by the method of claim 1 3 This is solved by the following features:

[0019] According to the invention, in this alternative embodiment of the invention, the second portion of the surface of the stator component is not coated, and the second portion of the surface has a manufacturing-induced roughness and / or coloration of 3 μm or more, preferably 5 μm or more, more preferably 10 μm or more, even more preferably 20 μm or more, particularly preferably 30 μm or more, even particularly preferably 40 μm or more, most preferably 50 μm or more, and in particular the coloration is obtained by adding at least one colorant to the starting material used in the manufacture of the stator component.

[0020] With regard to the preferred upper limit of the roughness resulting from the manufacture of the second part of the surface, what has already been said above applies.

[0021] In the present disclosure, unless otherwise stated, the term "roughness" is understood to mean the average roughness Rz according to DIN EN ISO 4287:2010-07.

[0022] The stator component according to the present invention has a surface with an increased emissivity ε at least in its second portion, which increases not only the heat transfer from the rotor to the stator but also the heat transfer from the stator to the housing. At the same time, the second portion is not coated, which improves the resistance performance and durability of the stator component compared to coated portions. Furthermore, the stator component according to the present invention is easy to manufacture, since the second portion can be left in the state obtained by molding immediately after production. Unlike the prior art, the present invention allows the surface to have an increased emissivity directly, without requiring any post-processing.

[0023] Although the present invention offers several alternative possibilities for solving the problem underlying the invention, the features and aspects that are optionally considered to be preferred and / or advantageous always relate to all alternatives of the invention mentioned herein, unless otherwise stated.

[0024] Particularly preferably, a first portion of the surface of the stator component is post-processed, in particular by separation, in particular by cutting. This makes the first portion particularly suitable for forming surfaces of stator components requiring high dimensional accuracy. Furthermore, it is particularly advantageous that the second portion is not post-processed, in particular by cutting. This not only reduces the amount of post-processing effort, but also allows for a high roughness of the second portion of the surface, and thus a correspondingly high thermal emissivity. This offers the significant advantage that a surface portion with increased emissivity is already obtained as a direct result of production, without any post-processing. In the prior art, an increase in emissivity could only be achieved through complex post-processing, in which case a coating must be attached to the stator component.

[0025] Within the scope of the present invention, it is not fundamentally excluded to subject not only the first portion of the surface but also the second portion to further processing, for example by separation, in particular by cutting, and in this case preferably the roughness of the second portion of the surface due to further processing is 3 μm, preferably 5 μm, So More preferably it is not below a value of 10 μm, particularly preferably 20 μm, even more particularly preferably 30 μm, very particularly preferably 40 μm and most preferably not below a value of 50 μm.

[0026] Furthermore, within the scope of the present invention, it is also possible to carry out a post-treatment of the second portion of the surface, which results in an increased roughness of the second portion of the surface. Such roughening of the second portion of the surface may be carried out, for example, by breaking the support structure, laser structuring, grinding or sandblasting, preferably by breaking the support structure or laser structuring, particularly preferably by laser structuring.

[0027] Destroying the support structure is understood to mean that the support structure is processed into at least the area of ​​the stator component to be roughened (i.e., at least part of the second portion of the surface) during molding of the stator component, in particular during additive manufacturing processes such as laser sintering or laser melting. The area of ​​the stator component to be roughened can be, for example, the grooves of a Holweck stator. After the molding process is completed, the support structure, for example, honeycomb-shaped, can be mechanically, e.g. manually, destroyed from the second portion of the surface of the stator component. In this way, a particularly high roughness can be achieved.

[0028] Such destruction of the support structure may be considered part of the manufacturing process, and not a post-processing process, in which case the surface characteristics or roughness caused by the destruction are manufacturing-induced roughness.

[0029] Furthermore, advantageously, the first portion of the surface at least partially forms a contact, mating or mass surface for one or more other components of the vacuum pump when the pump stage is assembled. The first and second portions of the surface may therefore have complementary or even mutually exclusive functions. In other words, the second portion of the surface may have properties, such as high roughness, that ensure the highest possible emissivity, while the first portion may be configured, for example by machining, to meet the tolerances required at certain points of the vacuum pump and / or to have a good fit and / or heat transfer in pump components that directly abut the first portion.

[0030] It is preferably envisaged that the stator component is a Holweck stator of a Holweck stage or a spacer ring of a turbopump stage, which allows for improved heat dissipation in the Holweck pump stage, the turbopump stage or both stages simultaneously, reducing the risk of overheating of the respective rotors or the common rotor.

[0031] If the stator component is a Holweck stator, the first portion of the surface particularly preferably forms the web tips and / or the outer flank of the Holweck stator. That is, the web tips between the grooves of the Holweck stator are adjacent to the radial gap between the rotor and the stator, also known as the Holweck gap, during pump operation, i.e., directly facing the rotor at a small distance. High dimensional accuracy is required at these locations for the function of the Holweck pump stage. This high accuracy is also required for the outer flank of the Holweck stator, regardless of whether the contact surfaces are configured for press-fitting or screw-fitting, in order to fit into the pump housing and ensure good heat transfer to surrounding parts of the pump housing. Therefore, it is also particularly preferred that the first portion of the surface, which forms the web tips and / or the outer flank of the Holweck stator, is reprocessed by separation, in particular by cutting.

[0032] If the stator component is a Holweck stator, then, alternatively or additionally, it is particularly preferred that the second portion of the surface forms at least part of the groove, in particular the entire groove of the Holweck stator. The groove only needs to meet low requirements for dimensional accuracy and can therefore be used to optimize the emissivity of the Holweck stator. Even with tolerance limitations in the grooves of the Holweck stator, it is possible, for example, to leave the surface with a high manufacturing roughness in order to obtain a correspondingly high thermal emissivity.

[0033] If the stator component is a spacer ring of a turbopump stage, it is particularly preferred that the first portion of the surface forms a contact point with the adjacent component. The adjacent component may be, for example, a spacer ring, a stator blade, or a pump housing. As already mentioned in the example of the Holweck stator, such contact surfaces require high dimensional accuracy to ensure a precise fit and the best possible heat transfer. Therefore, it is also particularly preferred that the first portion of the surface, which forms the contact surface of the spacer ring with other components of the pump, is reworked by separation, in particular by cutting.

[0034] If the stator component is a spacer ring of a turbopump stage, then, alternatively or additionally, it is particularly preferred that the second surface portion forms at least a portion of the inner diameter, in particular the entire inner diameter of a Holweck stator. The inner diameter only needs to meet low dimensional accuracy requirements and can therefore be used to optimize the emissivity of the spacer ring. Even with tolerance limitations along the inner diameter of the spacer ring, it is possible, for example, to leave the surface with a high manufacturing roughness in order to obtain a correspondingly high thermal emissivity.

[0035] Preferably, the stator components are manufactured by casting, sintering or additive methods. A common advantage of these molding methods is that they allow the production of parts with high manufacturing-induced roughness and consequently high thermal emissivity. Another advantage of the mentioned methods is that they allow the incorporation of colorants into the material to be molded.

[0036] Casting, i.e., filling a mold with a melt-flowable material and subsequently solidifying the melt, is a particularly easy and inexpensive forming method for producing stator components that meet the vacuum technical requirements. If the stator component is a cast component, the advantage is that the material can be transferred directly from an amorphous, flowable state to a shape that is close to the final contour. Preferably, a mold having a structured mold surface is used, which advantageously allows the roughness of at least a portion of the surface of the cast stator component to be precisely influenced.

[0037] The casting method applicable to the present invention is not limited in principle; the stator components can be produced, for example, by static casting (gravity casting or gravity casting) or, preferably, by dynamic casting (in particular centrifugal casting, low-pressure casting or pressure casting). Particularly preferably, the stator components are produced by pressure casting, in which the melt is forced into a permanent mold under high pressure. This method offers the advantage that extremely accurate contours can be reproduced. This pressure casting method can particularly preferably be vacuum pressure casting, which offers the advantage that higher material quality can be achieved, since the material contains relatively little air and other gases, which reduces the porosity of the cast part and increases its density and pressure tightness. Instead of a fully liquefied material, a partially fluid or pasty material can also be used as the casting material (so-called thixocasting or rheocasting).

[0038] If the stator component is a cast part, a casting mold with a structured surface can be preferably used for its production, so that the manufacturing-induced roughness in individual surface regions of the stator component can be influenced precisely, i.e., by local surface structuring of the casting mold in appropriate areas, the highest possible roughness can be achieved in the grooves of a cast Holweck stator or along the inner diameter of a cast spacer ring of a turbopump stage.

[0039] When sintering is used during molding, the stator components used in the vacuum pump according to the present invention are manufactured from powder or granular materials by using a molding and sintering process. The raw powder or granules are first compressed under pressure in a mold to form a compact. This green compact does not yet have significant strength. Therefore, subsequent sintering is essential for a stator component that can be used in vacuum technology. Sintering is a heat treatment at relatively high temperatures under a protective gas (e.g., nitrogen, hydrogen), primarily a solid-state reaction, possibly with a small liquid phase, that causes thermally activated material migration. As a result of sintering, the individual material particles bond together, forming a continuous sintered molded part with high strength. The pressing and sintering processes can be repeated as necessary, for example, to achieve additional compaction. If a high residual porosity (e.g., >12% by volume) remains in the stator component after sintering, the pore space can be filled in a separate step with another molten material (e.g., a metal or alloy) that has a lower melting point than the sintered body.

[0040] The term additive manufacturing (also called "3D printing") encompasses various forming techniques, which have in common that the production or shaping is carried out by interconnecting volume elements, in particular layers. Furthermore, in this case, the production of the stator components used in the vacuum pump according to the invention is not limited to a specific type of additive manufacturing. Examples of methods that can be used in the present invention include, by way of example only, powder bed fusion (PBF), in particular laser sintering, laser or electron beam melting, direct metal deposition (DMD) and directed energy deposition (DED).

[0041] Additive processes may be understood as manufacturing methods in which, starting from a mixture of material powder (e.g., ceramic or metal) and binder (e.g., polymer, wax, or adhesive), only a green body is produced by the actual additive manufacturing process, which is only transformed into the final product by conventional high-temperature post-processing, such as debinding and sintering. Thus, the green body of a stator component used in a vacuum pump according to the invention may be produced, for example, by layer-by-layer extrusion of the material powder-binder-mixture (strand deposition modeling or fused deposition modeling, FDM) or by so-called "binder jetting," in which the component is built up by applying a binder through a nozzle to the material powder layers.

[0042] When the stator components used in the vacuum pump of the present invention are manufactured by additive processes, at least one powder material is preferably used to manufacture the components. The powder material may be solidified in layers by physical processes, particularly thermal and / or chemical processes. The powder material may then be introduced into a mold and compressed, producing an at least substantially homogeneous material. By constructing the components from powder material, the components can be manufactured using additive manufacturing methods to a shape close to or at least approximately the final contour, which allows even particularly complex components to be manufactured inexpensively, with low material costs, and with little waste.

[0043] The specific casting, sintering and additive manufacturing methods described above are exemplary only and are not intended to be a definitive list of casting, sintering and additive methods that can be used with the present invention.

[0044] In principle, any material that meets the vacuum technical requirements may be used to manufacture the stator components used in the vacuum pump according to the invention, such as metallic materials, ceramic materials, metal matrix composites (MMC), plastics or plastic composites.

[0045] In this case, metallic materials and metal matrix composite materials are preferred because, in addition to favorable mechanical properties and good processability, these materials have particularly high thermal conductivity, which favors heat transfer from the stator component to the housing part abutting the stator component. Metals and alloys that can be used as metallic materials include, for example, aluminum, aluminum alloys, iron alloys, such as steel or cast iron, titanium, titanium alloys, nickel, nickel alloys, magnesium alloys, copper, copper alloys, and cobalt alloys. If the stator component of the present invention is manufactured from a metallic material, aluminum, aluminum alloys, titanium, titanium alloys, or iron alloys are preferably used, particularly preferably aluminum, aluminum alloys, or iron alloys, and most preferably aluminum or aluminum alloys.

[0046] In one preferred embodiment, the stator component is made of a metallic material, in particular aluminum or an aluminum alloy, in which case the second portion of the surface of the stator component has a roughness of 30 μm to 150 μm and an emissivity of 0.7 or greater.

[0047] Metal matrix composites consist of a continuous matrix of a metal or alloy in which particles or fibers of a non-metallic material are discontinuously dispersed. The non-metallic material dispersed in the metal matrix is ​​an inorganic material, such as a ceramic material (e.g., carbide, oxide, nitride, or boride) or an elemental non-metal or semi-metal (e.g., carbon, silicon). When the stator component of the present invention is manufactured from a metal matrix composite, the metal or alloy used as the metal matrix is ​​preferably aluminum, an aluminum alloy, an iron alloy (e.g., steel or cast iron), titanium, a titanium alloy, nickel, a nickel alloy, a magnesium alloy, copper, a copper alloy, or a cobalt alloy, particularly preferably aluminum, an aluminum alloy, an iron alloy, titanium, a titanium alloy, a magnesium alloy, copper, or a copper alloy, more preferably aluminum, an aluminum alloy, titanium, a titanium alloy, or a magnesium alloy, and most preferably aluminum, an aluminum alloy, titanium, or a titanium alloy. The non-metallic material may be an oxide or a non-oxide. Examples of suitable oxide ceramic materials include aluminum oxide and zirconium oxide. In particular, the ceramic material is a non-oxide. Non-oxide ceramics, such as nitrides, carbides, or borides, offer various advantages, such as high chemical and thermal stability and good thermal conductivity compared to oxide ceramics. Particularly suitable non-oxide ceramics are carbides, nitrides, silicides, or borides of aluminum, hafnium, lanthanum, molybdenum, tantalum, titanium, tungsten, zirconium, boron (in the case of carbides, nitrides, and silicides), or silicon (in the case of carbides, nitrides, and borides). Examples of suitable non-oxide ceramic materials are boron carbide, boron nitride, boron silicide (a boride of silicon), lanthanum hexaboride, molybdenum silicide, silicon carbide, silicon nitride, titanium boride, titanium carbide, titanium nitride, tungsten carbide, zirconium boride, and mixtures of two or more thereof. Boron carbide, silicon carbide, silicon nitride, titanium carbide and mixtures of two or more thereof are more preferred, with silicon carbide and silicon nitride being most preferred.

[0048] In addition to the nonmetallic elements such as Si or C and the ceramic materials already mentioned above, other inorganic substances may alternatively or additionally be used as the nonmetallic material in the metal matrix composite material. For example, metal oxides not listed in the general oxide ceramic materials may be used, such as preferably chromium oxide, iron oxide, cobalt oxide, manganese oxide, nickel oxide and / or titanium oxide, more preferably chromium oxide, iron oxide, manganese oxide and / or nickel oxide, even more preferably iron oxide and / or nickel oxide, and particularly preferably iron oxide.

[0049] The incorporation of non-metallic materials into the metallic matrix is ​​preferably carried out as described below in favor of the incorporation of non-metallic inorganic colorants into metallic materials.

[0050] A combination of different materials may be provided in the stator components. For example, one region of the component may consist of one material, while another region is made of a different material. A first region of the component may consist of a first material, for example aluminum, and a second region of the component may consist of a second metal, for example titanium, with a transition between the first and second metals, for example an aluminum-titanium transition, formed in the boundary region between the two regions by a metal-to-metal bond.

[0051] If the material from which the stator component is made is to be colored, this is preferably done by adding at least one colorant to the material before it is shaped to a shape close to or exactly like the final contour, in particular before the start of the molding process. The colorant is the substance that imparts color to the material. The term "colorant" here does not only mean a pigment in the narrow sense, i.e., a substance that is colored by itself, but also a substance that only becomes colored when combined with the material.

[0052] Within the scope of the present invention, the coloring of the surfaces of the stator components by coloring agents does not necessarily have to result in a visually perceptible color impression, i.e., a change in the emission spectrum in the visible range (λ = 0.38 μm to 0.78 μm), but may result solely in an increase in the absorption and emission capacity for infrared radiation. Infrared radiation is in particular electromagnetic radiation with a wavelength between 0.78 μm and 1 mm. In the relevant temperature range (rotor temperatures up to approximately 110 °C), practically all thermal radiation is emitted in the infrared range. Nevertheless, it is of course not excluded that the coloring can also be perceived by the naked eye, for example, as a gray or black coloring of the material.

[0053] The at least one colorant is a non-metallic inorganic material that can withstand the stresses imposed by the manufacturing process of the stator component and does not impair the vacuum technical compatibility of the stator component colored with the colorant, for example, in terms of mechanical and thermal stability. Preferably, the colorant is at least one elemental non-metal and / or at least one inorganic pigment and / or at least one ceramic material, more preferably at least one ceramic material and / or at least one inorganic pigment. The ceramic material may be an oxide or a non-oxide. Examples of suitable oxide ceramic materials are aluminum oxide and zirconium oxide. In particular, the ceramic material is a non-oxide. As mentioned above, non-oxide ceramics such as nitrides, carbides, or borides are advantageous compared to oxide ceramics. In this case, preferably, non-oxide ceramics, which have already been generally described as suitable in the context of metal matrix composites, are used.

[0054] As inorganic pigments, for example, at least one metal oxide may be used, preferably chromium oxide, iron oxide, cobalt oxide, manganese oxide, nickel oxide and / or titanium oxide, more preferably chromium oxide, iron oxide, manganese oxide and / or nickel oxide, even more preferably iron oxide and / or nickel oxide, particularly preferably iron oxide.

[0055] Preferably, a non-metallic inorganic colorant, in particular at least one elemental non-metal, at least one inorganic pigment, and / or at least one ceramic material, is incorporated into a metallic material, i.e., a metal or alloy. For this purpose, the aforementioned forming methods, i.e., casting, sintering, or additive manufacturing, may be preferably used. Thus, if the stator component is a cast part, the cast part is preferably produced from a mixed casting material that contains at least one colorant distributed therein in addition to at least one liquefied metal. This can be done, in particular, by stir casting. If the stator component is a sintered part, a suitable compact is preferably pressed from a mixture of at least one metal powder or metal granules that already contains at least one colorant powder or granules, and / or at least one molten metal material is wetted into the porous sintered body containing at least one colorant obtained after sintering. If the stator component is manufactured by an additive process, preferably, a powder or granules of at least one metal material is mixed with a powder or granules of at least one colorant and subjected to an additive process suitable for processing powdered metals, i.e., for example, laser sintering, laser melting, electron beam melting, direct metal deposition or directed energy deposition.

[0056] The metallic material may incorporate at least one colorant after the preferred method described above, and in this case the metallic material is preferably one of the metallic materials already mentioned above as suitable metal matrices in the context of metal matrix composites in general.

[0057] Typical emissivity of metals is in the range of ε≈0.1 to 0.4 (unless the surface is heavily oxidized or roughened), and even significantly lower in some cases for polished surfaces. In contrast, non-metallic materials may have significantly higher thermal emissivity than metals, typically ε≧0.6. Therefore, by embedding a non-metallic colorant in a metal matrix, the emissivity of the resulting composite can be significantly increased compared to the pure metallic material, without abandoning the advantages of the metal or alloy, such as favorable mechanical properties, good processing ability, or high thermal conductivity.

[0058] Embedding a suitable colorant into the material offers the advantage that no further surface treatment of the stator component is necessary to increase its emissivity, since the material is already colored immediately after molding, i.e., in its untreated state. Another important advantage is that the increased emissivity can be achieved regardless of the surface roughness. This means that increased emissivity can also be achieved on contact, mating, or mass surfaces that have been further processed by separation, for example, by cutting. Furthermore, both of the aforementioned possibilities for increasing emissivity can be combined within a stator component; that is, the stator component can be manufactured from a material incorporating a colorant, in which case surfaces that are not contact, mating, or mass surfaces can additionally be left with a high level of roughness due to manufacturing.

[0059] The subject of the invention is the subject of the independent claims 9 The problem is also solved by a method for manufacturing a stator component for a vacuum pump, in particular a stator for a turbomolecular pump, the vacuum pump comprising a housing and at least one pump stage arranged in the housing, the pump stage having a stator and a rotor which rotates relative to the stator about a rotation axis during operation and interacts with the stator to provide a pumping action, the stator component having a surface having a first portion and a second portion different from the first portion, the method comprising producing the stator component by molding, in particular by casting, sintering or an additive process, followed by post-processing of the first portion of the surface, in particular by separation, in particular by machining, and leaving the second portion of the surface unprocessed.

[0060] Preferably, the surface of the stator component is formed and / or the second portion of the surface is post-processed to a roughness of at least 3 μm, preferably at least 5 μm, more preferably at least 10 μm, even more preferably at least 20 μm, particularly preferably at least 30 μm, even more particularly preferably at least 40 μm, and most preferably at least 50 μm, with the advantages already mentioned above. As mentioned above, the optional post-processing of the second portion can be a separation, in particular a cutting process. However, in this case, the roughness of the second portion of the surface after post-processing is preferably not less than 3 μm, more preferably at least 5 μm, even more preferably at least 10 μm, particularly preferably at least 20 μm, even more particularly preferably at least 30 μm, even more preferably at least 40 μm, and most preferably at least 50 μm. As mentioned above, a post-treatment of the second portion of the surface may be carried out, which results in an increase in the roughness of the second portion. Such roughening of the second portion of the surface is carried out, for example, by breaking the support structure, laser structuring, grinding or sandblasting, preferably by breaking or laser structuring the support structure, particularly preferably by laser structuring, wherein breaking the support structure is as defined above.

[0061] In one example, a second portion of the surface of the stator component made from aluminum is treated by laser structuring so that the second portion has a roughness of 65 μm and an emissivity of 0.8.

[0062] Alternatively, the problem of the present invention is further solved by a method according to independent claim 12, which relates to a method for manufacturing a stator component for a stator of a vacuum pump, in particular a turbomolecular pump, the vacuum pump comprising a housing and at least one pump stage arranged in the housing, the pump stage having a stator and a rotor which rotates relative to the stator about a rotation axis in operation and interacts with the stator to provide a pumping effect, the stator component having a surface having a first portion and a second portion different from the first portion, the method comprising applying a colorant to the second portion of the surface, in particular by adding at least one colorant to at least one starting material used in manufacturing the stator component.

[0063] In this case, the stator parts are preferably produced by casting, sintering or additive processes, which entails the advantages already mentioned above.

[0064] In each of the methods according to the invention described, it is furthermore advantageous to process a first portion of the surface to form, at least in part, a contact, mating or mass surface relative to one or more other parts of the vacuum pump, with the advantages already mentioned above.

[0065] In each of the methods according to the invention described, it is further preferred if the manufactured stator component is a Holweck stator of a Holweck pump stage or a spacer ring of a turbopump stage.

[0066] Naturally, the methods described in the specification can be adapted to suit the configurations and particular features described in relation to the device, and vice versa.

[0067] The invention will now be described by way of example and on the basis of advantageous embodiments with reference to the accompanying drawings, in which: FIG. [Brief explanation of the drawings]

[0068] [Figure 1] 1 shows a perspective view of a known turbomolecular pump. [Figure 2] The turbomolecular pump of FIG. 1 is shown in bottom view. [Figure 3] 3 shows a cross-sectional view of a turbomolecular pump taken along the section line AA shown in FIG. 2. [Figure 4] 3 shows a cross-sectional view of the turbomolecular pump taken along the section line BB shown in FIG. 2. [Figure 5] 3 shows a cross-sectional view of the turbomolecular pump taken along the section line CC shown in FIG. 2. [Figure 6a] 1 shows a cross-sectional view of a conventional Holweck system. [Figure 6b] 1 shows a cross-sectional view of a Holweck system with a stator surface having enhanced emissivity. [Figure 7]1 shows a cross-sectional view of a Holweck region with a Holweck stator sleeve having a roughened grooved surface due to manufacturing. [Figure 8] FIG. 8 is a detailed view of a portion of the Holweck region of FIG. 7. [Figure 9] 1 illustrates, in cross section, a turbopump stage with a spacer ring having a rough surface at its inner diameter due to manufacturing. [Figure 10] FIG. 10 is a detailed view of a portion of the turbopump stage of FIG. [Figure 11] 1 shows in cross section the Holweck region where the inner Holweck rotor sleeve is separated from the motor space of the pump by a wall with high thermal emissivity. DETAILED DESCRIPTION OF THE INVENTION

[0069] The turbomolecular pump 111 shown in Figure 1 has a pump inlet 115 surrounded by an inlet flange 113. A recipient (not shown) may be connected to the pump inlet 115 in a manner known per se. Gas coming from the recipient can be drawn in from the recipient via the pump inlet 115 and pumped through the pump to a pump outlet 117. An auxiliary vacuum pump, such as a rotary vane pump, may be connected to the pump outlet 117.

[0070] The inlet flange 113 forms the upper end of a housing 119 of the vacuum pump 111 in the orientation of the vacuum pump according to Fig. 1. The housing 119 has a lower part 121. Arranged laterally on the lower part 121 is an electronics housing 123. The electronics housing 123 accommodates electrical and / or electronic components of the vacuum pump 111, for example for operating an electric motor 125 (see also Fig. 3) arranged in the vacuum pump. The electronics housing 123 is provided with a number of connections 127 for accessories. Furthermore, a data interface 129 (for example according to the RS485 standard) and a current supply connection 131 are arranged on the electronics housing 123.

[0071] There are also turbomolecular pumps that do not have this type of attached electronics housing, but are connected to external drive electronics.

[0072] The housing 119 of the turbomolecular pump 111 is provided with a ventilation inlet 133, particularly in the form of a ventilation valve. The vacuum pump 111 can be vented via the ventilation inlet 133. A seal gas connection 135 (also called a purge gas connection) is also arranged in the region of the lower part 121. A purge gas can be introduced into a motor space 137 via the seal gas connection 135 to protect the electric motor 125 (see, for example, FIG. 3 ) from the gas pumped by the pump. The electric motor 125 is accommodated in the motor space 137 of the vacuum pump 111. Two coolant connections 139 are also arranged in the lower part 121. One coolant connection serves as a coolant inlet and the other as an outlet. A coolant can be introduced into the vacuum pump for cooling purposes. The other turbomolecular vacuum pump present (not shown) is operated exclusively air-cooled.

[0073] The underside 141 of the vacuum pump can be used as a base, so that the vacuum pump 111 can be operated in a vertical position relative to the underside 141. Moreover, the vacuum pump 111 can be fixed to the recipient via the inlet flange 113 and thus operated in a suspended state, so to speak. Furthermore, the vacuum pump 111 can be configured so that it can be operated even when oriented in a different direction than that shown in FIG. 1. Vacuum pump configurations are also possible in which the underside 141 can be arranged not only facing downwards, but also facing sideways or upwards. In this case, any angle is conceivable in principle.

[0074] In particular, other turbomolecular vacuum pumps (not shown) that exist, which are larger than the pump shown, cannot be operated in a vertical position.

[0075] 2 further comprises various screws 143. These screws 143 secure components of the vacuum pump, not specifically identified here, to one another. For example, a bearing cover 145 is secured to the lower surface 141.

[0076] Further fastening holes 147 are arranged in the underside 141. Via the fastening holes 147, the pump 111 can be fixed, for example, to a mounting surface. This is not possible with other existing turbomolecular vacuum pumps (not shown), in particular those larger than the pump shown.

[0077] 2 to 5 show a coolant line 148 in which a coolant can be circulated, the coolant being introduced and withdrawn via the coolant connection 139.

[0078] As shown in the cross-sectional views of Figures 3-5, the vacuum pump has multiple process gas pumping stages for pumping process gas acting on a pump inlet 115 to a pump outlet 117.

[0079] A rotor 149 is disposed within the housing 119. The rotor 149 has a rotor shaft 153 that is rotatable about a rotation axis 151.

[0080] The turbomolecular pump 111 has multiple turbomolecular pump stages connected in series to provide a pumping action. Each turbomolecular pump stage has multiple radially extending rotor blades 155 fixed to the rotor shaft 153 and multiple stator vanes 157 arranged between the rotor blades 155 and fixed within the housing 119. In this case, each rotor blade 155 and its adjacent stator vane 157 form one turbomolecular pump stage. The stator vanes 157 are held at a desired axial distance from each other by spacer rings 159.

[0081] The vacuum pump further comprises Holweck pump stages arranged radially inside and outside one another and connected in series to provide a pumping action. There are alternative turbomolecular vacuum pumps (not shown) that do not have Holweck pump stages.

[0082] The rotor of the Holweck pump stage includes a rotor hub 161 disposed on the rotor shaft 153 and two cylindrically sided Holweck rotor sleeves 163, 165 fixed to and supported by the rotor hub 161. The Holweck rotor sleeves 163, 165 are oriented coaxially with respect to the rotation axis 151 and engage radially with one another. Two cylindrically sided Holweck stator sleeves 167, 169 are also provided. The Holweck stator sleeves 167, 169 are likewise oriented coaxially with respect to the rotation axis 151 and engage radially with one another.

[0083] The pumping surfaces of the Holweck pump stages are formed by the side surfaces, i.e., the radially inner and / or outer surfaces of the Holweck rotor sleeves 163, 165 and the Holweck stator sleeves 167, 169. The radially inner surface of the outer Holweck stator sleeve 167 faces the radially outer surface of the outer Holweck rotor sleeve 163, forming a radial Holweck gap 171, and together with this outer surface forms the first Holweck pump stage following the turbomolecular pump. The radially inner surface of the outer Holweck rotor sleeve 163 faces the radially outer surface of the inner Holweck stator sleeve 169, forming a radial Holweck gap 173, and together with this outer surface forms the second Holweck pump stage. The radially inner surface of the inner Holweck stator sleeve 169 opposes the radially outer surface of the inner Holweck rotor sleeve 165, forming a radial Holweck gap 175, and together with this outer surface forms the third Holweck pump stage.

[0084] A radially extending channel may be provided at the lower end of the Holweck rotor sleeve 163. The radially outer Holweck gap 171 is connected to the central Holweck gap 173 via the channel. A further radially extending channel may be provided at the upper end of the inner Holweck stator sleeve 169. The central Holweck gap 173 is connected to the radially inner Holweck gap 175 via the channel. This allows multiple Holweck pump stages that engage with each other inward and outward to be connected in series with each other. The radially inner lower end of the Holweck rotor sleeve 165 is pump A connecting channel 179 leading to the exhaust port 117 may also be provided.

[0085] The pumping surfaces of the Holweck stator sleeves 167, 169 each have a plurality of Holweck grooves that extend axially and spirally around the rotation axis 151. On the other hand, the opposing sides of the Holweck rotor sleeves 163, 165 are smoothly formed and pump gas for operating the vacuum pump 111 forward in the Holweck grooves.

[0086] For the rotatable support of the rotor shaft 153, a rolling bearing 181 is provided in the region of the pump outlet 117 and a permanent magnetic bearing 183 is provided in the region of the pump inlet 115.

[0087] In the region of the rolling bearing 181, the rotor shaft 153 is provided with a conical splash nut 185. The splash nut 185 has an outer diameter that increases towards the rolling bearing 181. The splash nut 185 is in sliding contact with at least one scraping element of the working medium reservoir. In other existing turbomolecular vacuum pumps (not shown), a splash screw may be provided instead of a splash nut. This allows for various configurations to be realised, so that the term "splash tip" is also used in this context.

[0088] The working medium reservoir comprises a number of absorbent discs 187 stacked one above the other, which are impregnated with a working medium, e.g., a lubricant, for the rolling bearings 181.

[0089] During operation of the vacuum pump 111, the working medium is transferred by capillary action from the working medium reservoir via the scraping element to the rotating splash nut 185 and is then forced by centrifugal force along the splash nut 185 towards the increasing outer diameter of the splash nut 185 towards the rolling bearing 181, where it performs, for example, a lubrication function. The rolling bearing 181 and the working medium reservoir are enclosed in the vacuum pump by a trough-like insert 189 and a bearing cover 145.

[0090] The permanent magnet magnetic bearing 183 has a rotor-side bearing half 191 and a stator-side bearing half 193. Each half has a ring stack, which consists of multiple rings 195, 197 of permanent magnets stacked axially one above the other. The ring magnets 195, 197 face each other, forming a radial bearing gap 199, with the rotor-side ring magnet 195 positioned radially outward and the stator-side ring magnet 197 positioned radially inward. The magnetic field present in the bearing gap 199 generates a magnetic repulsion force between the ring magnets 195, 197. This repulsion force provides radial support for the rotor shaft 153. The rotor-side ring magnet 195 is supported by a support portion 201 of the rotor shaft 153. The support portion 201 surrounds the ring magnet 195 radially outward. The stator-side ring magnet 197 is supported by a support portion 203 of the stator shaft 153. The support portion 203 extends through the ring magnet 197 and is suspended on radial struts 205 of the housing 119. Parallel to the rotation axis 151, the ring magnet 195 on the rotor side is supported by the support portion 203. 201 The ring magnet 197 on the stator side is fixed by a cover element 207 connected to the support part 203 in one direction parallel to the rotation axis 151. supportThe ring 209 is fixed by a fixing ring 211 coupled to the support portion 203. A disc spring 213 may further be provided between the fixing ring 211 and the ring magnet 197.

[0091] Within the magnetic bearing, an emergency or safety bearing 215 is provided. for The bearing or safety bearing 215 runs freely without contact during normal operation of the vacuum pump and only engages if the rotor 149 is displaced too far radially relative to the stator, thereby forming a radial stop for the rotor 149 so that collisions between rotor-side and stator-side structures are prevented. The safety bearing 215 is configured as a non-lubricated rolling bearing and forms a radial gap with the rotor 149 and / or the stator. This gap prevents the safety bearing 215 from engaging during normal pump operation. The radial displacement that the safety bearing 215 engages is dimensioned to be sufficiently large so that the safety bearing 215 does not engage during normal operation of the vacuum pump, and at the same time is sufficiently small so that collisions between rotor-side and stator-side structures are prevented under all circumstances.

[0092] The vacuum pump 111 has an electric motor 125 that rotates a rotor 149. The armature of the electric motor 125 is formed by the rotor 149. A rotor shaft 153 of the rotor 149 extends through a motor stator 217. A permanent magnet assembly may be disposed on the portion of the rotor shaft 153 that extends through the motor stator 217, either radially outwardly or embedded therein. An intermediate chamber 219 is disposed between the motor stator 217 and the portion of the rotor 149 that extends through the motor stator 217. room 219 has a radial motor gap through which the motor stator 217 and the permanent magnet assembly may magnetically interact to transmit driving torque.

[0093] The motor stator 217 is fixed in the housing in a motor space 137 provided for the electric motor 125. A seal gas connection 135 allows a seal gas (also called purge gas, which may be, for example, air or nitrogen) to reach the motor space 137. The seal gas protects the electric motor 125 against process gases, for example corrosive parts of the process gas. The motor space 137 may be evacuated via the pump outlet 117, i.e., a vacuum pressure is applied to the motor space 137 at least approximately, which is achieved by an auxiliary vacuum pump connected to the pump outlet 117.

[0094] A so-called labyrinth seal 223, known per se, may further be provided between the rotor hub 161 and the wall 221 that defines the motor space 137. This allows for a more precise seal, particularly for the motor space relative to the radially outer Holweck pump stages. 137 A better seal is achieved.

[0095] The pump is provided with at least one stator component according to the invention, which interacts with the rotor to provide pumping action in a pump stage, and which stator component, in particular a Holweck stator of a Holweck pump stage and / or a spacer ring of a turbomolecular stage, has the features set out in one of the independent claims. Advantageously, the pump may be provided with several stator components, in particular several Holweck stators in a Holweck pump stage and / or several spacer rings in a turbopump stage. Particularly advantageously, all stator components which interact with the rotor to provide pumping action in a pump stage, in particular all Holweck stators of all Holweck pump stages and / or all spacer rings of all turbomolecular stages of the pump, are stator components configured according to the invention.

[0096] 6a and 6b are schematic cross-sectional views comparing two different Holweck systems. The rotor hub 61, which is disposed on a rotor shaft 53 that rotates about an axis 51 during operation, and the multiple radially interlocking, cylindrically sided Holweck rotor sleeves 63, 65 attached to the rotor hub 61 are identical in the Holweck system of FIG. 6a and the Holweck system of FIG. 6b and may be configured in a conventional manner. However, the radially interlocking, cylindrically sided Holweck stator sleeves 67, 69 or 68, 70 are different.

[0097] The system shown in Figure 6a has conventional Holweck stator sleeves 67, 69 which do not have any enhanced thermal emissivity.

[0098] In contrast, the system shown in Figure 6b includes Holweck stator sleeves 68, 70 according to the invention, the dotted surfaces of which have increased thermal emissivity relative to conventional sleeves 67, 69, thus providing improved heat dissipation. This applies in Figure 6b to both the radially inner and outer surfaces of the inner Holweck stator sleeve 70 and the radially inner surface of the outer Holweck stator sleeve 68.

[0099] Specifically, the surfaces having enhanced thermal emissivity in this case include the surfaces of webs 681, including the surfaces of web tips 683, and the surfaces of grooves 685 located between webs 681, on the radially inner surface of outer Holweck stator sleeve 68, as well as the surfaces of web tips 703 and 704 and grooves 705 and 706 on the radially outer and inner surfaces of inner Holweck stator sleeve 70, as well as channel-like surfaces 721, 741, and 761 that form channels 72, 74, and 76. Radially extending channel 72 connects first Holweck gap 71 and second Holweck gap 73, and is defined on one side by lower end 631 of outer Holweck rotor sleeve 63 and on the other side by channel-like stator surface 721. A radially extending channel 74 connects the second Holweck gap 73 and the third Holweck gap 75 and is defined on one side by the rotor hub 61 and on the other side by the upper surface 741 of the inner stator sleeve 70. A radially extending channel 76 connects the third Holweck gap 75 and an exhaust port (not shown) and is defined on one side by the lower end of the inner Holweck rotor sleeve 65 and on the other side by a channel-side stator surface 761.

[0100] In the embodiment shown in Figure 6b, in each of the three Holweck pump stages, the stator surface opposite the rotor surface has an increased thermal emissivity across its entirety, so that enhanced heat transfer occurs from the rotor to the stator by thermal radiation across the Holweck gaps 71, 73, 75, respectively.

[0101] As can also be seen from Figure 6b, the outer side surface 689 of the outer stator sleeve 68 does not have enhanced thermal emissivity. Enhanced thermal emissivity is not necessary here because the outer surface 689 is used to mate with the pump housing (not shown). In other words, here, under pump operating conditions, there is no gap across which heat transfer via radiation must occur; heat transfer occurs directly from the outer side surface 689 to the adjacent housing portion (not shown).

[0102] Of course, within the scope of the present invention, other embodiments that differ from the Holweck system configuration shown diagrammatically in Figure 6b are also possible, in particular it is conceivable that not all stator surfaces, as shown by dots in Figure 6b, but only some of these surfaces have an increased thermal emissivity.

[0103] For example, the contact surfaces of the stator components against other parts of the pump as well as the web tips 683 , 703 , 704 and / or the channel-side Holweck stator surfaces 721, 741, 761 may also be advantageously configured without an entirely or partially increased thermal emissivity. This is particularly meaningful when an increased thermal emissivity is to be achieved by high roughness, but this may impair the high dimensional accuracy required to form the narrow Holweck gaps 71, 73, 75 or channels 72, 74, 76 between the rotor and the stator. In this case, the increased thermal emissivity may remain limited in particular to surfaces of the stator components, for example the surfaces of the grooves 685, 705, 706 of the Holweck stator sleeves 68, 70, which have lower dimensional accuracy requirements.

[0104] Figures 7 and 8 illustrate such an embodiment, showing the Holweck region of a turbomolecular pump where the grooves 685, 705, 706 in the inner and outer Holweck stator sleeves 68, 70 have rough surfaces due to manufacturing. Figure 8 shows, in an enlarged cross-section, a portion of the Holweck region of Figure 7 at the lower end of the Holweck stator sleeve.

[0105] The irregularities of the groove surfaces are greatly exaggerated in Figures 7 and 8 for clarity and are not drawn to scale. In this embodiment, only the surfaces of the grooves 685, 705, 706 have a high manufacturing roughness and therefore a high thermal emissivity. The remaining surfaces of the stator components shown in Figures 7 and 8, in particular the web tips 683, 703, 704 of the inner and outer Holweck stator sleeves 68, 70 and the contact surfaces of the stator components with other pump parts, such as the outer flank 689 of the outer Holweck stator sleeve 68, are made smooth by machining, which allows the required tolerances to be maintained and ensures good heat transfer at the contact surfaces.

[0106] Moreover, as can be seen in particular from Figure 7, in the Holweck stage, a large part of the stator surface facing the rotor sleeve is occupied by grooves 685, 705, 706 rather than by web tips 683, 703, 704. Therefore, machining of relatively small surface areas, such as web tips 683, 703, 704, by cutting does not significantly impair the heat radiation from the rotor to the stator. The differently configured surfaces of the Holweck stator sleeve complement each other in an optimal way, thereby achieving the best possible heat dissipation from the rotor to the stator (via the rough grooves 685, 705, 706) and subsequently from the stator to the housing (via the smooth outer surface 689).

[0107] Figure 9 shows several turbopump stages connected in series, each formed of a rotor blade 55 attached to a rotor shaft 53 and an adjacent stator vane 57, the stator vanes 57 being axially spaced apart from one another by spacer rings 59. Figure 10 shows an enlarged view of the spacer ring 59 according to Figure 9.

[0108] Along the inner diameter of each spacer ring 59, the inner diameter surface 591 of the spacer ring 59 faces the rotor blade 55. In this case, the distance between the radially outer end of the rotor blade 55 and the inner diameter surface 591 of the spacer ring 59 is large enough to allow the spacer ring 59 to be used despite tolerance limitations, and the entire inner diameter surface 591 is not machined after molding. Therefore, because the entire inner diameter surface 591 of the spacer ring 59 is not machined, the inner diameter surface 591 has a high roughness due to manufacturing and therefore a high thermal emissivity. This applies to all spacer rings 59 used, as shown in FIG. 9, so that radiative heat transport from the rotor to the stator is maximized in the turbomolecular pump stage of the pump.

[0109] As can be seen in particular from the enlarged view in Figure 10, the contact surfaces 599 of the spacer rings 59 with the adjacent spacer rings 59, the stator blades 57, and the housing 19 are smoothed by machining, which ensures the required fit and, in particular, good heat transfer to the housing. In contrast, the majority of the surface directly facing the rotor blades 55 and therefore able to absorb the thermal radiation emitted by the rotor blades 55 is occupied by a surface 591 with high emissivity, as can be seen in Figure 9. The differently shaped surfaces of the spacer rings 59 complement each other in an optimal way, thereby achieving the best possible heat transfer from the rotor to the stator (via the rough inner diameter surface 591) and then from the stator to the housing (via the smooth contact surface 599).

[0110] Figure 11 shows another embodiment in which the wall 22 defining the motor space 37 of the pump is configured as a stator component in accordance with the present invention. The surface 23 of the wall 22 facing the inner Holweck rotor sleeve 65, shown as a dot in Figure 11, has an increased thermal emissivity compared to conventional walls. This allows the surface 23 of the wall 22 to enhance heat dissipation from the rotor by radiation across the gap 24 separating the inner Holweck rotor sleeve 65 from the wall 22.

[0111] Of course, the features shown in Figures 6 to 11 may be combined with one another in any way, so that, for example, in a turbomolecular pump it is possible to incorporate and use simultaneously one or more Holweck stator sleeves 68, 70 as shown in Figure 6b, 7 or 8, one or more spacer rings 59 as shown in Figure 9 or 10 and / or one or more wall sections 22 as shown in Figure 11, which is highly advantageous due to the improved heat dissipation that results therefrom. The present application relates to the invention described in the claims, but also includes the following as other aspects. 1. In vacuum pumps, especially turbomolecular pumps, a housing; and at least one pump stage disposed within the housing, the pump stage including a stator and a rotor that rotates relative to the stator about a rotational axis during operation and interacts with the stator to provide a pumping action, the stator having at least one stator component with a surface having a first portion and a second portion different from the first portion; A vacuum pump wherein a second portion of said surface is uncoated and has a thermal emissivity ε at 50°C of at least 0.25, preferably at least 0.3. 2. In vacuum pumps, especially turbomolecular pumps, a housing; and at least one pump stage disposed within the housing, the pump stage including a stator and a rotor that rotates relative to the stator about a rotational axis during operation and interacts with the stator to provide a pumping action, the stator having at least one stator component with a surface having a first portion and a second portion different from the first portion; A vacuum pump, wherein the second portion of the surface has surface properties resulting from manufacturing and not altered by post-processing or coating by separation. 3. The second portion of the surface has a manufacturing-induced surface characteristic that is characterized by an average roughness Rz 3. The vacuum pump according to claim 2, wherein the roughness and / or coloring is 3 μm or more, preferably 5 μm or more, and more preferably 10 μm or more, expressed as a roughness of 3 μm or more, preferably 5 μm or more, and more preferably 10 μm or more, and in particular the coloring is obtained by adding at least one coloring agent to a starting material used in the manufacture of the stator component. 4. In vacuum pumps, especially turbomolecular pumps, a housing; and at least one pump stage disposed within the housing, the pump stage including a stator and a rotor that rotates relative to the stator about a rotational axis during operation and interacts with the stator to provide a pumping action, the stator having at least one stator component with a surface having a first portion and a second portion different from the first portion; a second portion of the surface is uncoated; a second portion of the surface having a manufacturing-induced roughness and / or coloration, expressed as average roughness Rz in accordance with DIN EN ISO 4287:2010-07 of 3 μm or more, preferably 5 μm or more, more preferably 10 μm or more, wherein the coloration is obtained by adding at least one coloring agent to the starting material used in the manufacture of the stator part; 5. 10. The vacuum pump of claim 9, wherein the first portion of the surface is post-machined, in particular post-machined by separation, in particular machined. 6. 10. Any one of the preceding vacuum pumps, wherein the first portion of the surface at least partially forms a contact, mating or mass surface for one or more other components of the vacuum pump when the pump stage is assembled. 7. Any one of the preceding vacuum pumps, wherein the stator component is a Holweck stator of a Holweck pump stage or a spacer ring of a turbo pump stage. 8. Any one of the preceding vacuum pumps, wherein said stator components are manufactured by casting, sintering or additive processes. 9. 10. Any one of the preceding vacuum pumps, wherein said stator component is obtained or obtainable by any one of the following methods. 10. A method for manufacturing a stator component for a vacuum pump, in particular a turbomolecular pump stator, comprising: A vacuum pump comprising a housing and at least one pump stage disposed within the housing, the pump stage having a stator and a rotor which rotates relative to the stator about an axis of rotation in operation and interacts with the stator to provide a pumping action, the stator component having a surface having a first portion and a second portion different from the first portion; The method comprises producing the stator part by molding, in particular by casting, sintering or additive processes, followed by post-processing, in particular by separation, in particular by machining, of a first part of the surface, in particular leaving a second part of the surface unprocessed. 11. By forming the surface of the stator component and / or by further processing a second part of the surface, the surface has an average roughness R z 11. The method of claim 10, wherein the roughness is in the range of 3 μm or more, preferably 5 μm or more, and more preferably 10 μm or more, expressed as 12. A method for manufacturing a stator component for a vacuum pump, in particular a turbomolecular pump stator, comprising: A vacuum pump comprising a housing and at least one pump stage disposed within the housing, the pump stage having a stator and a rotor which rotates relative to the stator about an axis of rotation in operation and interacts with the stator to provide a pumping action, the stator component having a surface having a first portion and a second portion different from the first portion; During the process, the second portion of the surface is provided with a color, in particular by adding at least one coloring agent to at least one starting material used in manufacturing the stator component. 13. 13. The method of claim 12, wherein the stator component is manufactured by a casting process, a sintering process, or an additive process. 14. The method of any one of claims 10 to 13, wherein a first portion of the surface is at least partially machined to form a contact, mating or mass surface for one or more other components of the vacuum pump. 15. 15. The method of any one of claims 10 to 14, wherein the stator component is a Holweck stator of a Holweck pump stage or a spacer ring of a turbopump stage. [Explanation of symbols]

[0112] 22 Wall 23 Surface 24 Gap 37 Motor Space 51 Rotation axis 53 rotor shaft 55 Moving blade 57 Stator blade 59 Spacer ring 61 rotor hub 63 Outer Holbeck rotor sleeve 65 Inner Holbeck Rotor Sleeve 67 Outer Holbeck Sterling Sleeve 68 Outer Holbeck Sterling Sleeve 69 Inner Holbeck Sterling Sleeve 70 Inner Holbeck Sterling Sleeve 71 Holbeck Gap 72 channels 73 Holbeck Gap 74 channels 75 Holbeck Gap 76 channels 111 Turbomolecular pump 113 Intake flange 115 Pump intake 117 Pump exhaust port 119 Housing 121 Lower part 123 Electronics Housing 125 electric motor 127 Accessory Connection 129 Data Interface 131 Current supply connection 133 Ventilation intake 135 Seal gas connection 137 Motor Space 139 Coolant Connection 141 Bottom surface 143 Screw 145 Bearing cover 147 Fixed hole 148 Coolant line 149 Rotor 151 Rotation axis 153 rotor shaft 155 Moving blade 157 Stator blade 159 Spacer ring 161 rotor hub 163 Holbeck Rotor Sleeve 165 Holbeck Rotor Sleeve 167 Holbeck Sterling Sleeve 169 Holbeck Sterling Sleeve 171 Holbeck Gap 173 Holbeck Gap 175 Holbeck Gap 179 Connection Channels 181 Rolling bearings 183 Permanent magnet type magnetic bearing 185 Splash Nut 187 discs 189 Insert 191 Rotor side bearing half 193 Stator side bearing half 195 Ring Magnet 197 Ring Magnet 199 Bearing clearance 201 Support part 203 Support part 205 Radial Struts 207 Cover Elements 209 Support Ring 211 Fixing ring 213 Disc spring 215 Emergency bearings or safety bearings 217 Motor Stator 219 Intermediate Room 221 Wall section 223 Labyrinth Seal 591 Inner diameter surface 681 Web 683 Web Tip 685 Groove 701 Web 702 Web 703 Web Tip 704 Web Tip 705 Groove 706 Groove 721 Channel-shaped stator surface 741 Channel-shaped stator surface 761 Channel-shaped stator surface

Claims

1. In a vacuum pump, a housing; and at least one pump stage disposed within the housing, the pump stage having a stator and a rotor that rotates relative to the stator about a rotational axis during operation and interacts with the stator to provide a pumping action, the stator having at least one stator component with a surface having a first portion and a second portion distinct from the first portion in which enhanced heat transfer occurs from the rotor to the stator by thermal radiation; The vacuum pump, wherein the second portion of the surface has an as-formed surface at the time of manufacture, is uncoated, and has a thermal emissivity ε of at least 0.25 at 50°C.

2. In a vacuum pump, a housing; and at least one pump stage disposed within the housing, the pump stage having a stator and a rotor that rotates relative to the stator about a rotational axis during operation and interacts with the stator to provide a pumping action, the stator having at least one stator component with a surface having a first portion and a second portion distinct from the first portion in which enhanced heat transfer occurs from the rotor to the stator by thermal radiation; The second portion of the surface has an as-formed surface during manufacture, and the surface properties of the second portion of the surface are such that the average roughness R ｚ and / or coloring, wherein the coloring is obtained by adding at least one coloring agent to a starting material used in the manufacture of said stator component, which coloring agent increases the radiation absorption and emission capabilities of said starting material.

3. In a vacuum pump, a housing; and at least one pump stage disposed within the housing, the pump stage having a stator and a rotor that rotates relative to the stator about a rotational axis during operation and interacts with the stator to provide a pumping action, the stator having at least one stator component with a surface having a first portion and a second portion distinct from the first portion in which enhanced heat transfer occurs from the rotor to the stator by thermal radiation; a second portion of the surface is uncoated; 10. A vacuum pump comprising: a second portion of the surface having an as-formed surface during manufacture, the surface of the second portion having a roughness, expressed as average roughness Rz according to DIN EN ISO 4287:2010-07, of 3 μm or more and / or a coloration, the coloration being obtained by adding at least one colorant to a starting material used during manufacture of the stator component, the coloration increasing the radiation absorption and emission capabilities of the starting material.

4. 4. A vacuum pump according to claim 1, wherein the first portion of the surface is post-molded, post-molded by separation, or machined.

5. 4. A vacuum pump according to claim 1, wherein the first portion of the surface at least partially forms a contact or mating surface for one or more further parts of the vacuum pump when the pump stage is assembled.

6. 4. A vacuum pump according to any one of claims 1 to 3, wherein the stator part is a Holweck stator of a Holweck pump stage or a spacer ring of a turbo pump stage.

7. 4. A vacuum pump according to any one of claims 1 to 3, wherein the stator components are manufactured by casting, sintering or additive processes.

8. 4. The vacuum pump according to claim 1, wherein the vacuum pump is a turbomolecular pump.

9. 1. A method for manufacturing a stator component for a vacuum pump stator, comprising: A vacuum pump comprising a housing and at least one pump stage disposed within the housing, the pump stage having a stator and a rotor which rotates relative to the stator about a rotational axis in operation and interacts with the stator to provide a pumping action, the stator component having a surface having a first portion and a second portion distinct from the first portion in which enhanced heat transfer from the rotor to the stator occurs by thermal radiation; During the method, the stator component is produced by molding, and by molding the surface of the stator component has an average roughness R ｚ in the range of 3 μm or greater, whereby a first portion of the surface is subjected to a post-forming process and a second portion of the surface remains formed.

10. The method of claim 9 , wherein the forming is by casting, sintering, or additive processes.

11. The method according to claim 9 , wherein the post-processing after molding is post-processing by separation or cutting.

12. 1. A method for manufacturing a stator component for a vacuum pump stator, comprising: A vacuum pump comprising a housing and at least one pump stage disposed within the housing, the pump stage having a stator and a rotor which rotates relative to the stator about a rotational axis in operation and interacts with the stator to provide a pumping action, the stator component having a surface having a first portion and a second portion distinct from the first portion in which enhanced heat transfer from the rotor to the stator occurs by thermal radiation; The method further comprises providing a color to a second portion of the surface by adding at least one colorant to at least one starting material used in manufacturing the stator component, the colorant increasing the radiation absorption and emission capabilities of the first portion of the surface, followed by post-molding processing of the first portion of the surface, and leaving the second portion of the surface as molded.

13. The method of claim 12 , wherein the stator component is manufactured by a casting process, a sintering process, or an additive process.

14. 14. A method according to any one of claims 9 to 13, wherein a first portion of the surface is at least partially machined to form a contact or mating surface for one or more further components of a vacuum pump.

15. 14. The method according to any one of claims 9 to 13, wherein the stator component is a Holweck stator of a Holweck pump stage or a spacer ring of a turbopump stage.

16. 14. The method according to any one of claims 9 to 13, wherein the vacuum pump is a turbomolecular pump.

17. A vacuum pump, wherein the stator component is manufactured by a method according to any one of claims 9 to 13.

18. 18. A vacuum pump according to claim 17, wherein the second portion of the surface of the stator component has a thermal emissivity ε of at least 0.25 at 50°C.

Images