EP4390144A2 - Vacuum pump - Google Patents

Abstract

The invention relates to a vacuum pump, in particular a turbomolecular pump, with a rotor shaft that rotates about an axis of rotation during operation and with at least one rotor component fastened to the rotor shaft, wherein the rotor component is a rotor disk that comprises a radially inner collar, via which the rotor disk is fastened to the rotor shaft, and a plurality of rotor blades, each of which is integrally connected to the collar and which each extend radially outward from a blade base on the collar and have a free blade end radially outward, or wherein the rotor component is a Holweck component, in particular a Holweck hub or a Holweck sleeve, and wherein the rotor disk and/or the Holweck component are made of an aluminum alloy that has the following elements in weight percent: Cu: 3.6-4.4; Mg: 1.2-1.4; Mn: 0.5-0.8; Zr: <0.16; Ti: 0.01-0.05; Si <0.21; Fe < 0.21; Zn < 0.26; other elements < 0.06; balance aluminium.

Description

The invention relates to a vacuum pump, in particular a turbomolecular pump, with a rotor shaft rotating about an axis of rotation during operation and with at least one rotor component fastened to the rotor shaft.

The pumping effect of such vacuum pumps results from the interaction of a pumping or pump-active area of the rotor component with a pumping or pump-active area of a respective stator component. A turbomolecular pump, for example, has several rotor disks as rotor components, each of which comprises several rotor blades as pumping areas and interacts with stator disks arranged relative to a housing of the pump. A Holweck pump comprises one or more Holweck sleeves that rotate during operation and are attached to a Holweck hub that is fastened to the rotor shaft. A Holweck sleeve interacts with one or more Holweck stators, the cylindrical outer surface and/or the cylindrical inner surface of the Holweck sleeve representing the pumping area that interacts with one or more Holweck grooves, each of which is designed as a pumping area on the respective Holweck stator.

Known turbomolecular pumps often have not only one or more turbomolecular pump stages, but additionally one or more Holweck pump stages arranged downstream of at least one turbomolecular pump stage.

The pumping performance of a vacuum pump is determined in particular by its (gas-dependent) suction capacity, which for a particular gas essentially depends on the geometry of the rotor and stator components as well as on the speed of the rotor components. The speed is usually a fixed device value for a particular pump type, which indicates the speed at which the pump can be operated continuously in normal operation. This speed is also referred to below as the nominal speed.

However, for a particular pump type, it is not possible to arbitrarily increase the pumping performance by increasing the speed, as high speeds lead to increased stresses in the material of the rotor components and, due to the higher gas friction, also to higher, no longer permissible temperatures of the rotor components. This is because conditions must be avoided in which the material of the rotor components deforms beyond a tolerable level during operation and, in particular, begins to flow. Higher speeds also increase the demands on any rolling bearing used to support the rotor shaft and its lubrication, in particular on the lubricating oil used for this. Nor can the pumping performance be arbitrarily increased simply by increasing the diameter of the rotor and stator components, as this results in higher orbital velocities for the radially outer areas of the rotor components at the same speeds, in particular for the blade ends of the rotor blades of rotor disks.

These limitations make it difficult or even impossible to increase the pumping performance of existing vacuum pumps.

The object of the invention is to remedy this situation.

This problem is solved by the features of the independent claims.

• Cu: 3,6 - 4,4
• Mg: 1,2 - 1,4
• Mn : 0,5 - 0,8
• Zr: < 0,16
• Ti : 0,01 - 0,05
• Si < 0,21
• Fe < 0,21
• Zn < 0,26
• andere Elemente < 0,06,
• Rest Aluminium.

According to a first aspect of the invention, it is provided that the at least one rotor component of the vacuum pump, which is either a rotor disk or a Holweck component, is made of an aluminium alloy containing the following elements in % by weight:

• Cu: 3.6 - 4.4
• Mg: 1.2 - 1.4
• Mn: 0.5 - 0.8
• Zr: < 0.16
• Ti : 0.01 - 0.05
• Si < 0.21
• Fe < 0.21
• Zn < 0.26
• other elements < 0.06,
• Rest aluminum.

This aluminum alloy is also referred to below simply as "the aluminum alloy" or as "the material according to the invention".

It was found that other geometries, higher rated speeds and higher rotor component temperatures are possible if those rotating components of a vacuum pump which as a whole or at least relevant areas of which have a comparatively large radial distance from the axis of rotation of the rotor shaft are made of the above-mentioned aluminum alloy.

It can be provided that each rotor component of the vacuum pump is made from the material according to the invention. However, this is not mandatory. For example, it is possible that all rotor disks of a turbomolecular pump stage are made from the aluminum alloy, whereas the rotating components of one or more Holweck pump stages arranged downstream are not made from this aluminum alloy.

It is also possible to manufacture only some of the rotor disks of a turbomolecular pump stage or only some of the rotating components of a Holweck pump stage from the aluminum alloy. In a Holweck pump stage, for example, it can be provided that the Holweck hub is made from the aluminum alloy, but the or each Holweck sleeve attached to the Holweck hub is not.

According to further aspects of the invention, it has been found that certain geometries relating to one or more rotor components, namely certain dimensions and/or dimensional ratios and combinations thereof, enable a higher pumping performance.

According to one aspect of the invention, in a vacuum pump defined by embodiment 2, it is particularly provided that the rotor disk has a rotor outer diameter DA which is measured between two imaginary diametrically opposed blade ends, that the Holweck hub has a Holweck outer diameter DHW which is measured between two diametrically opposed points of a radial outer surface of the Holweck hub, and that the rotor outer diameter DA is larger than the Holweck outer diameter DHW by a factor of at least 1.22, preferably at least 1.25, particularly preferably at least 1.30.

This concept means a relative reduction in the diameter of the Holweck hub (and thus the diameter of a Holweck sleeve attached to the radially outer end of the Holweck hub) compared to the rotor outer diameter of the rotor disk. This reduction results in lower gas friction in the Holweck pumping stage, which in turn enables an increase in the speed and thus a higher blade end speed of the rotor disk. It has been found that this concept results in an overall higher pumping performance.

According to a further aspect of the invention, in a vacuum pump defined by embodiment 3, it is particularly provided that the rotor disk has a rotor outer diameter DA which is measured between two imaginary diametrically opposed blade ends, that the rotor disk has a collar outer diameter DB which is measured between two diametrically opposed points of a radial outer surface of the collar, that the rotor disk has a base outer diameter DG which is measured from blade base to blade base of two imaginary diametrically opposed rotor blades, and that the difference DA - DG is greater than the difference DA - DB by a factor of at least 0.94, preferably at least 0.95, particularly preferably at least 0.97.

In comparison to known rotor disks, this concept means an increase in the proportion of the pump-effective area of each rotor blade, which is measured from the blade base, to the blade length measured from the collar. This allows the proportion of the pump-effective length of each rotor blade to be increased and thus the overall pumping performance of the vacuum pump to be increased.

According to a further aspect of the invention, in a vacuum pump defined by embodiment 4, it is particularly provided that the rotor disk has a base outer diameter DG, which is measured from blade base to blade base of two imaginary diametrically opposed rotor blades, that the rotor shaft has a shaft outer diameter DI, and that DG is larger than DI by a factor of at most 1.20, preferably at most 1.15, particularly preferably at most 1.10.

This concept leads to a relative reduction of the portion of the rotor disk - in relation to the radial direction - which has no or at most only a comparatively very low pumping efficiency.

The shaft outer diameter DI corresponds to the inner diameter of the rotor disk collar.

Preferably, the rotor disks are each a one-piece component which is manufactured from a starting material by milling and/or sawing.

Advantageous further developments of the individual aspects of the invention are specified in the dependent claims, the following description and the drawing. Unless otherwise stated, all further developments relate to all aspects of the invention mentioned, i.e. all aspects and further developments can be combined with one another unless otherwise stated or combinations are clearly excluded.

In the vacuum pumps according to the invention according to embodiments 2, 3 and 4, a particularly pronounced increase in pumping performance can be achieved if the respective rotor component or components is or are made of the aluminum alloy. This material allows higher speeds under otherwise identical conditions without the problems mentioned in the introductory section arising due to excessive stresses in the material of the rotor components and/or due to excessive temperatures of the rotor components.

In some embodiments of the invention, it can be provided that the rotor disk has a rotor outer diameter DA that is greater than 5.0 cm, preferably in a range of 5.0 cm to 60 cm, wherein the rotor outer diameter DA is measured between two imaginary diametrically opposite blade ends.

According to some developments of the invention, it can be provided that the rotor disk has a rotor outer diameter DA which is measured between two imaginary diametrically opposed blade ends, wherein the Holweck hub has a Holweck outer diameter DHW which is measured between two diametrically opposed points of a radial outer surface of the Holweck hub, and wherein the rotor outer diameter DA is at least 135 mm and the Holweck outer diameter DHW is at least 108 mm or the rotor outer diameter DA is 120 mm and the Holweck outer diameter DHW is 99 mm.

According to some embodiments, it can be provided that the rotor disk has a rotor outer diameter DA which is measured between two imaginary diametrically opposed blade ends, and that the vacuum pump comprises a second Holweck hub which has a Holweck outer diameter DHW which is measured between two diametrically opposed points of a radial outer surface of the second Holweck hub, wherein the Holweck outer diameter DHW2 of the second Holweck hub is at least 91 mm, and/or wherein the rotor outer diameter DA is larger than the Holweck outer diameter DHW2 of the second Holweck hub by a factor of at least 1.40, preferably of at least 1.48.

A magnetic bearing or a hybrid bearing can be provided for the rotor shaft. If a hybrid bearing is provided, a permanent magnet bearing is provided on the high vacuum side and a roller bearing on the pre-vacuum side. The structure and arrangement of magnetic bearings and roller bearings for rotor shafts of vacuum pumps are generally known to those skilled in the art, so that this does not need to be discussed in more detail. In this regard, reference is also made to the the Fig. 1 to 5 described embodiment of a turbomolecular pump.

It has already been mentioned elsewhere that it is possible for all rotor disks of a turbomolecular pump stage to be made of the aluminum alloy defined by embodiment 1, but that this is not mandatory.

In other words, in some embodiments of the invention, it can be provided that several rotor disks are attached to the rotor shaft, with at least two rotor disks differing from one another in terms of the material from which they are made. It can be provided that at least one of the rotor disks is made of the aluminum alloy.

According to some developments, it can be provided that one or more rotor disks on the high vacuum side are made of the aluminum alloy, whereas one or more rotor disks on the pre-vacuum side are made of a different material. In other words, it is therefore provided that the aluminum alloy according to the invention is not used for all rotor disks, but only for a high vacuum side part of the rotor disks.

In some embodiments of the invention, it can be provided that the Holweck sleeve and/or the Holweck hub has or have an outer diameter DHH or DHW which is measured between two diametrically opposite points of a radial outer surface of the Holweck sleeve or the Holweck hub and which lies in the range of 5.0 cm to 60 cm.

According to some developments of the invention, the rotor component can have an outer diameter greater than 10 cm, preferably greater than 15 cm, particularly preferably greater than 20 cm, wherein the outer diameter is between measured at two diametrically opposite points, each located on a radial outer surface of the rotor component.

According to further embodiments, it can be provided that the collar of the rotor disk and/or the Holweck hub have an axial height in the range of 3.0 mm to 5.9 mm, in particular up to 5.49 mm.

According to some developments of the invention, the rotor blades can each have a blade thickness in the range of 0.125 mm to 2.9 mm if the blade thickness - seen in the radial direction - is measured in the middle between the blade base and the blade end.

In some embodiments, it can be provided that the rotor blades each have a thickness of less than 9.8 mm, in particular less than 9.0 mm, at the blade base.

The blade thickness at a respective location - viewed in the radial direction - is defined in the context of the present disclosure as the smallest diameter of a sectional surface of the rotor blade in a sectional plane running perpendicular to the radial direction.

According to a further aspect of the invention, it relates to a method for operating a vacuum pump, in particular a vacuum pump as disclosed herein, wherein the vacuum pump comprises a rotor shaft rotating about an axis of rotation during operation and at least one rotor component fastened to the rotor shaft, wherein in the method the vacuum pump is operated at a speed of the rotor shaft such that the maximum permissible temperature of the rotor component is greater than 90°C, in particular greater than or equal to 98°C, particularly preferably greater than or equal to 120°C.

In particular, the rotor component is a rotor disk which comprises a radially inner collar, via which the rotor disk is fastened to the rotor shaft, and a plurality of rotor blades, each of which is integrally connected to the collar and which extend radially outward from a blade base on the collar and have a free blade end radially outward, or a Holweck component, in particular a Holweck hub or a Holweck sleeve.

A maximum permissible temperature of the rotor components of more than 90°C enables the vacuum pump to be operated as intended at a higher nominal speed than with known vacuum pumps, where the maximum permissible temperature of the rotor components is limited to 90°C. The higher speed can increase the pump performance.

It has been found that the aluminum alloy defined by embodiment 1 is a material that allows maximum permissible temperatures of more than 90°C for rotor components of vacuum pumps, in particular for rotor disks and/or Holweck components, without causing the problems mentioned above.

According to some embodiments of the method according to the invention, it can be provided that the vacuum pump is operated at a speed of the rotor shaft such that the blade end speed of the rotor disk is more than 420 m/s, preferably more than 438 m/s, particularly preferably more than 464 m/s.

In known vacuum pumps, the blade end speed of the rotor disk, i.e. the path speed of the blade ends during operation with the rotor shaft rotating at the rated speed, is limited to a maximum of 420 m/s.

The higher rated speed can increase the pumping performance of the vacuum pump.

According to some embodiments of the invention, it can be provided that the vacuum pump is operated at a speed of the rotor shaft which is more than 59,000 revolutions per minute, preferably more than 100,000 revolutions per minute, particularly preferably more than 150,000 revolutions per minute.

In some developments of the invention, namely both the vacuum pumps according to the invention according to the individual aspects mentioned and the method according to the invention, it can be provided that the rotor shaft is supported on the pre-vacuum side by a rolling bearing that is lubricated with an oil that is a synthetic oil that has a kinematic viscosity in the range of 4.5 to 6.5 mm ² /s at 100 ° C (viscosity measured according to ASTM D445 - 17a). A preferred example of such an oil is the oil called "AeroShell Turbine Oil 560". With regard to further properties and possible embodiments of a synthetic oil with the above-mentioned viscosity properties, reference is made to the European patent application published on May 13, 2020. EP 3 650 702 A1 the contents of which are hereby incorporated by reference to specify the said synthetic oil.

1. 1. Vakuumpumpe, insbesondere Turbomolekularpumpe, mit einer während des Betriebs um eine Drehachse (11) rotierenden Rotorwelle (13) und mit wenigstens einem auf der Rotorwelle (13) befestigten Rotorbauteil (15, 17, 18),
   • wobei das Rotorbauteil eine Rotorscheibe (15) ist, die einen radial innen liegenden Bund (19), über den die Rotorscheibe (15) auf der Rotorwelle (13) befestigt ist, und mehrere Rotorschaufeln (21) umfasst, die jeweils integral mit dem Bund (19) verbunden sind und die sich jeweils ausgehend von einem Schaufelgrund (23) am Bund (19) radial nach außen erstrecken und radial außen ein freies Schaufelende (25) aufweisen, oder wobei das Rotorbauteil ein Holweckbauteil ist, insbesondere eine Holwecknabe (17) oder eine Holweckhülse (18), und
   • wobei die Rotorscheibe (15) und/oder das Holweckbauteil (17, 18) aus einer Aluminiumlegierung gefertigt sind bzw. ist, die folgende Elemente in Gewichts-% aufweist:
     • Cu: 3,6 - 4,4
     • Mg: 1,2 - 1,4
     • Mn : 0,5 - 0,8
     • Zr: < 0,16
     • Ti : 0,01 - 0,05
     • Si < 0,21
     • Fe < 0,21
     • Zn < 0,26
     • andere Elemente < 0,06,
     • Rest Aluminium.
2. 2. Vakuumpumpe, insbesondere Turbomolekularpumpe,
   • mit einer während des Betriebs um eine Drehachse (11) rotierenden Rotorwelle (13),
   • mit wenigstens einer auf der Rotorwelle (13) befestigten Rotorscheibe (15), die einen radial innen liegenden Bund (19), über den die Rotorscheibe (15) auf der Rotorwelle (13) befestigt ist, und mehrere Rotorschaufeln (21) umfasst, die jeweils integral mit dem Bund (19) verbunden sind und die sich jeweils ausgehend von einem Schaufelgrund (23) am Bund (19) radial nach außen erstrecken und radial außen ein freies Schaufelende (25) aufweisen, und
   • mit wenigstens einer auf der Rotorwelle (13) befestigten Holwecknabe (17), an der zumindest eine Holweckhülse (18) befestigt ist,
   • wobei die Rotorscheibe (15) einen Rotoraußendurchmesser DA aufweist, der zwischen zwei gedachten einander diametral gegenüberliegenden Schaufelenden (25) gemessen wird,
   • wobei die Holwecknabe (17) einen Holweckaußendurchmesser DHW aufweist, der zwischen zwei einander diametral gegenüberliegenden Punkten einer radialen Außenfläche der Holwecknabe (17) gemessen wird, und wobei der Rotoraußendurchmesser DA um einen Faktor von mindestens 1,22, bevorzugt von mindestens 1,25, besonders bevorzugt von mindestens 1,30, größer ist als der Holweckaußendurchmesser DHW.
3. 3. Vakuumpumpe, insbesondere Turbomolekularpumpe,
   • mit einer während des Betriebs um eine Drehachse (11) rotierenden Rotorwelle (13), und
   • mit wenigstens einer auf der Rotorwelle (13) befestigten Rotorscheibe (15), die einen radial innen liegenden Bund (19), über den die Rotorscheibe (15) auf der Rotorwelle (13) befestigt ist, und mehrere Rotorschaufeln (21) umfasst, die jeweils integral mit dem Bund (19) verbunden sind und die sich jeweils ausgehend von einem Schaufelgrund (23) am Bund (19) radial nach außen erstrecken und radial außen ein freies Schaufelende (25) aufweisen, wobei die Rotorscheibe (15) einen Rotoraußendurchmesser DA aufweist, der zwischen zwei gedachten einander diametral gegenüberliegenden Schaufelenden (25) gemessen wird,
   • wobei die Rotorscheibe (15) einen Bundaußendurchmesser DB aufweist, der zwischen zwei einander diametral gegenüberliegenden Punkten einer radialen Außenfläche des Bundes (19) gemessen wird,
   • wobei die Rotorscheibe (15) einen Grundaußendurchmesser DG aufweist, der von Schaufelgrund (23) zu Schaufelgrund (23) von zwei gedachten einander diametral gegenüberliegenden Rotorschaufeln (21) gemessen wird,
   • wobei DA - DG um einen Faktor von mindestens 0,94, bevorzugt von mindestens 0,95, besonders bevorzugt von mindestens 0,97, größer ist als DA - DB.
4. 4. Vakuumpumpe, insbesondere Turbomolekularpumpe,
   • mit einer während des Betriebs um eine Drehachse (11) rotierenden Rotorwelle (13),
   • mit wenigstens einer auf der Rotorwelle (13) befestigten Rotorscheibe (15), die einen radial innen liegenden Bund (19), über den die Rotorscheibe (15) auf der Rotorwelle (13) befestigt ist, und mehrere Rotorschaufeln (21) umfasst, die jeweils integral mit dem Bund (19) verbunden sind und die sich jeweils ausgehend von einem Schaufelgrund (23) am Bund (19) radial nach außen erstrecken und radial außen ein freies Schaufelende (25) aufweisen, wobei die Rotorscheibe (15) einen Grundaußendurchmesser DG aufweist, der von Schaufelgrund (23) zu Schaufelgrund (23) von zwei gedachten einander diametral gegenüberliegenden Rotorschaufeln (21) gemessen wird, wobei die Rotorwelle (13) einen Wellenaußendurchmesser DI aufweist, und wobei DG um einen Faktor von maximal 1,20, bevorzugt von maximal 1,15, besonders bevorzugt von maximal 1,10, größer ist als DI.
5. 5. Vakuumpumpe nach einer der Ausführungsformen 2 bis 4,
   wobei die Rotorscheibe (15) und/oder die Holwecknabe (17) und/oder die Holweckhülse (18) aus einer Aluminiumlegierung gefertigt sind bzw. ist, die folgende Zusammensetzung in Gewichts-% aufweist:
   • Cu: 3,6 - 4,4
   • Mg: 1,2 - 1,4
   • Mn : 0,5 - 0,8
   • Zr: < 0,16
   • Ti : 0,01 - 0,05
   • Si < 0,21
   • Fe < 0,21
   • Zn < 0,26
   • andere Elemente < 0,06,
   • Rest Aluminium.
6. 6. Vakuumpumpe nach einer der vorhergehenden Ausführungsformen, wobei die Rotorscheibe (15) einen Rotoraußendurchmesser DA aufweist, der größer als 5,0 cm ist, vorzugsweise in einem Bereich von 5,0 cm bis 60 cm liegt, wobei der Rotoraußendurchmesser DA zwischen zwei gedachten einander diametral gegenüberliegenden Schaufelenden (25) gemessen wird.
7. 7. Vakuumpumpe nach einer der vorhergehenden Ausführungsformen, wobei die Rotorscheibe (15) einen Rotoraußendurchmesser DA aufweist, der zwischen zwei gedachten einander diametral gegenüberliegenden Schaufelenden (25) gemessen wird,
   wobei die Holwecknabe (17) einen Holweckaußendurchmesser DHW aufweist, der zwischen zwei einander diametral gegenüberliegenden Punkten einer radialen Außenfläche der Holwecknabe (17) gemessen wird, und wobei der Rotoraußendurchmesser DA mindestens 135 mm und der Holweckaußendurchmesser DHW mindestens 108 mm betragen, oder wobei der Rotoraußendurchmesser DA 120 mm und der Holweckaußendurchmesser DHW 99 mm betragen.
8. 8. Vakuumpumpe nach einer der vorhergehenden Ausführungsformen, wobei die Rotorscheibe (15) einen Rotoraußendurchmesser DA aufweist, der zwischen zwei gedachten einander diametral gegenüberliegenden Schaufelenden (25) gemessen wird,
   • wobei die Vakuumpumpe eine zweite Holwecknabe umfasst, die einen Holweckaußendurchmesser DHW2 aufweist, der zwischen zwei einander diametral gegenüberliegenden Punkten einer radialen Außenfläche der zweiten Holwecknabe gemessen wird,
   • wobei der Holweckaußendurchmesser DHW2 der zweiten Holwecknabe mindestens 91 mm beträgt,
   • und/oder wobei der Rotoraußendurchmesser DA um einen Faktor von mindestens 1,40, vorzugsweise von mindestens 1,48, größer ist als der Holweckaußendurchmesser DHW2 der zweiten Holwecknabe.
9. 9. Vakuumpumpe nach einer der vorhergehenden Ausführungsformen, wobei die Rotorwelle (13) eine Magnetlagerung oder eine Hybridlagerung, nämlich hochvakuumseitig ein Permanentmagnetlager (35) und vorvakuumseitig ein Wälzlager (37), aufweist.
10. 10. Vakuumpumpe nach einer der vorhergehenden Ausführungsformen, wobei auf der Rotorwelle (13) mehrere Rotorscheiben (15) befestigt sind, wobei wenigstens zwei Rotorscheiben (15) sich hinsichtlich des Materials, aus dem sie gefertigt sind, voneinander unterscheiden, insbesondere wobei zumindest eine der Rotorscheiben (15) aus der Aluminiumlegierung gefertigt ist.
11. 11. Vakuumpumpe nach einer der vorhergehenden Ausführungsformen, wobei die Holweckhülse (18) und/oder die Holwecknabe (17) einen Außendurchmesser DHH bzw. DHW aufweist bzw. aufweisen, der zwischen zwei einander diametral gegenüberliegenden Punkten einer radialen Außenfläche der Holweckhülse (18) bzw. der Holwecknabe (17) gemessen wird und der im Bereich von 5,0 cm bis 60 cm liegt.
12. 12. Vakuumpumpe nach einer der vorhergehenden Ausführungsformen, wobei das Rotorbauteil (15, 17, 18) einen Außendurchmesser größer als 10 cm, bevorzugt größer als 15 cm, insbesondere bevorzugt größer als 20 cm, aufweist, wobei der Außendurchmesser zwischen zwei einander diametral gegenüberliegenden Punkten gemessen wird, die jeweils auf einer radialen Außenfläche des Rotorbauteils (15, 17, 18) liegen.
13. 13. Verfahren zum Betreiben einer Vakuumpumpe, insbesondere einer Vakuumpumpe nach einer der vorhergehenden Ausführungsformen, wobei die Vakuumpumpe eine während des Betriebs um eine Drehachse (11) rotierende Rotorwelle (13) und wenigstens ein auf der Rotorwelle (13) befestigtes Rotorbauteil (15, 17, 18) umfasst,
    • insbesondere wobei das Rotorbauteil eine Rotorscheibe (15), die einen radial innen liegenden Bund (19), über den die Rotorscheibe (15) auf der Rotorwelle (13) befestigt ist, und mehrere Rotorschaufeln (21) umfasst, die jeweils integral mit dem Bund (19) verbunden sind und die sich jeweils ausgehend von einem Schaufelgrund (23) am Bund (19) radial nach außen erstrecken und radial außen ein freies Schaufelende (25) aufweisen, oder ein Holweckbauteil ist, insbesondere eine Holwecknabe (17) oder eine Holweckhülse (18),
    • wobei bei dem Verfahren die Vakuumpumpe mit einer Drehzahl der Rotorwelle (13) derart betrieben wird, dass die maximal zulässige Temperatur des Rotorbauteils (15, 17, 18) größer 90°C, insbesondere größer oder gleich 98°C, besonders bevorzugt größer oder gleich 120°C, ist.
14. 14. Verfahren nach Ausführungsform 13,
    wobei die Vakuumpumpe mit einer Drehzahl der Rotorwelle (13) derart betrieben wird, dass die Schaufelendengeschwindigkeit der Rotorscheibe (15) mehr als 420 m/s, bevorzugt mehr als 438 m/s, bevorzugt mehr als 464 m/s, beträgt.
15. 15. Verfahren nach Ausführungsform 13 oder 14,
    wobei die Vakuumpumpe mit einer Drehzahl der Rotorwelle (13) betrieben wird, die mehr als 59.000 Umdrehungen pro Minute, bevorzugt mehr als 100.000 Umdrehungen pro Minute, besonders bevorzugt mehr als 150.000 Umdrehungen pro Minute, beträgt.

The invention particularly relates to the following embodiments:

1. 1. Vacuum pump, in particular a turbomolecular pump, with a rotor shaft (13) rotating about an axis of rotation (11) during operation and with at least one rotor component (15, 17, 18) fastened to the rotor shaft (13),
   • wherein the rotor component is a rotor disk (15) having a radially inner collar (19) over which the rotor disk (15) is mounted on the rotor shaft (13) and comprises a plurality of rotor blades (21), each of which is integrally connected to the collar (19) and which each extend radially outwardly from a blade base (23) on the collar (19) and have a free blade end (25) radially outward, or wherein the rotor component is a Holweck component, in particular a Holweck hub (17) or a Holweck sleeve (18), and
   • wherein the rotor disk (15) and/or the Holweck component (17, 18) are made of an aluminium alloy which has the following elements in weight %:
     • Cu: 3.6 - 4.4
     • Mg: 1.2 - 1.4
     • Mn: 0.5 - 0.8
     • Zr: < 0.16
     • Ti : 0.01 - 0.05
     • Si < 0.21
     • Fe < 0.21
     • Zn < 0.26
     • other elements < 0.06,
     • Rest aluminum.
2. 2. Vacuum pump, in particular turbomolecular pump,
   • with a rotor shaft (13) rotating about a rotation axis (11) during operation,
   • with at least one rotor disk (15) fastened to the rotor shaft (13), which comprises a radially inner collar (19) via which the rotor disk (15) is fastened to the rotor shaft (13), and a plurality of rotor blades (21), each of which is integrally connected to the collar (19) and which each extend radially outward from a blade base (23) on the collar (19) and have a free blade end (25) radially outward, and
   • with at least one Holweck hub (17) attached to the rotor shaft (13), to which at least one Holweck sleeve (18) is attached,
   • wherein the rotor disk (15) has a rotor outer diameter DA which is measured between two imaginary diametrically opposite blade ends (25),
   • wherein the Holweck hub (17) has a Holweck outer diameter DHW which is measured between two diametrically opposite points of a radial outer surface of the Holweck hub (17), and wherein the rotor outer diameter DA is larger than the Holweck outer diameter DHW by a factor of at least 1.22, preferably of at least 1.25, particularly preferably of at least 1.30.
3. 3. Vacuum pump, in particular turbomolecular pump,
   • with a rotor shaft (13) rotating about a rotation axis (11) during operation, and
   • with at least one rotor disk (15) fastened to the rotor shaft (13), which comprises a radially inner collar (19) via which the rotor disk (15) is fastened to the rotor shaft (13), and a plurality of rotor blades (21), each of which is integrally connected to the collar (19) and which each extend radially outward from a blade base (23) on the collar (19) and have a free blade end (25) radially outward, wherein the rotor disk (15) has a rotor outer diameter DA which is measured between two imaginary diametrically opposite blade ends (25),
   • wherein the rotor disk (15) has a collar outer diameter DB which is measured between two diametrically opposite points of a radial outer surface of the collar (19),
   • wherein the rotor disk (15) has a basic outer diameter DG which is measured from blade base (23) to blade base (23) of two imaginary diametrically opposed rotor blades (21),
   • wherein DA - DG is greater than DA - DB by a factor of at least 0.94, preferably at least 0.95, particularly preferably at least 0.97.
4. 4. Vacuum pump, in particular turbomolecular pump,
   • with a rotor shaft (13) rotating about a rotation axis (11) during operation,
   • with at least one rotor disk (15) fastened to the rotor shaft (13), which comprises a radially inner collar (19) via which the rotor disk (15) is fastened to the rotor shaft (13), and a plurality of rotor blades (21), each of which is integrally connected to the collar (19) and which each extend radially outwards from a blade base (23) on the collar (19) and have a free blade end (25) radially outwards, wherein the rotor disk (15) has a base outer diameter DG which is measured from blade base (23) to blade base (23) of two imaginary diametrically opposed rotor blades (21), wherein the rotor shaft (13) has a shaft outer diameter DI, and wherein DG is larger than DI by a factor of at most 1.20, preferably at most 1.15, particularly preferably at most 1.10.
5. 5. Vacuum pump according to one of embodiments 2 to 4,
   wherein the rotor disk (15) and/or the Holweck hub (17) and/or the Holweck sleeve (18) are made of an aluminium alloy having the following composition in weight %:
   • Cu: 3.6 - 4.4
   • Mg: 1.2 - 1.4
   • Mn: 0.5 - 0.8
   • Zr: < 0.16
   • Ti : 0.01 - 0.05
   • Si < 0.21
   • Fe < 0.21
   • Zn < 0.26
   • other elements < 0.06,
   • Rest aluminum.
6. 6. Vacuum pump according to one of the preceding embodiments, wherein the rotor disk (15) has a rotor outer diameter DA which is greater than 5.0 cm, preferably in a range of 5.0 cm to 60 cm, wherein the rotor outer diameter DA is measured between two imaginary diametrically opposite blade ends (25).
7. 7. Vacuum pump according to one of the preceding embodiments, wherein the rotor disk (15) has a rotor outer diameter DA which is measured between two imaginary diametrically opposite blade ends (25),
   wherein the Holweck hub (17) has a Holweck outer diameter DHW which is measured between two diametrically opposite points of a radial outer surface of the Holweck hub (17), and wherein the rotor outer diameter DA is at least 135 mm and the Holweck outer diameter DHW is at least 108 mm, or wherein the rotor outer diameter DA is 120 mm and the Holweck outer diameter DHW is 99 mm.
8. 8. Vacuum pump according to one of the preceding embodiments, wherein the rotor disk (15) has a rotor outer diameter DA which is measured between two imaginary diametrically opposite blade ends (25),
   • wherein the vacuum pump comprises a second Holweck hub having a Holweck outer diameter DHW2 which is between two mutually diametrically opposite points of a radial outer surface of the second Holweck hub,
   • where the Holweck outer diameter DHW2 of the second Holweck hub is at least 91 mm,
   • and/or wherein the rotor outer diameter DA is larger than the Holweck outer diameter DHW2 of the second Holweck hub by a factor of at least 1.40, preferably at least 1.48.
9. 9. Vacuum pump according to one of the preceding embodiments, wherein the rotor shaft (13) has a magnetic bearing or a hybrid bearing, namely a permanent magnet bearing (35) on the high vacuum side and a rolling bearing (37) on the fore vacuum side.
10. 10. Vacuum pump according to one of the preceding embodiments, wherein a plurality of rotor disks (15) are fastened to the rotor shaft (13), wherein at least two rotor disks (15) differ from one another with regard to the material from which they are made, in particular wherein at least one of the rotor disks (15) is made of the aluminum alloy.
11. 11. Vacuum pump according to one of the preceding embodiments, wherein the Holweck sleeve (18) and/or the Holweck hub (17) has/have an outer diameter DHH or DHW which is measured between two diametrically opposite points of a radial outer surface of the Holweck sleeve (18) or the Holweck hub (17) and which lies in the range of 5.0 cm to 60 cm.
12. 12. Vacuum pump according to one of the preceding embodiments, wherein the rotor component (15, 17, 18) has an outer diameter greater than 10 cm, preferably greater than 15 cm, particularly preferably greater than 20 cm, wherein the outer diameter is measured between two diametrically opposite points, each of which is located on a radial outer surface of the rotor component (15, 17, 18).
13. 13. Method for operating a vacuum pump, in particular a vacuum pump according to one of the preceding embodiments, wherein the vacuum pump comprises a rotor shaft (13) rotating about an axis of rotation (11) during operation and at least one rotor component (15, 17, 18) fastened to the rotor shaft (13),
    • in particular, wherein the rotor component comprises a rotor disk (15) which has a radially inner collar (19) via which the rotor disk (15) is fastened to the rotor shaft (13), and a plurality of rotor blades (21), each of which is integrally connected to the collar (19) and which each extend radially outward from a blade base (23) on the collar (19) and have a free blade end (25) radially outward, or is a Holweck component, in particular a Holweck hub (17) or a Holweck sleeve (18),
    • wherein in the method the vacuum pump is operated at a speed of the rotor shaft (13) such that the maximum permissible temperature of the rotor component (15, 17, 18) is greater than 90°C, in particular greater than or equal to 98°C, particularly preferably greater than or equal to 120°C.
14. 14. Method according to embodiment 13,
    wherein the vacuum pump is operated at a speed of the rotor shaft (13) such that the blade end speed of the rotor disk (15) is more than 420 m/s, preferably more than 438 m/s, preferably more than 464 m/s.
15. 15. Method according to embodiment 13 or 14,
    wherein the vacuum pump is operated at a speed of the rotor shaft (13) which is more than 59,000 revolutions per minute, preferably more than 100,000 revolutions per minute, particularly preferably more than 150,000 revolutions per minute.

Fig. 1

eine perspektivische Ansicht einer Turbomolekularpumpe,

Fig. 2

eine Ansicht der Unterseite der Turbomolekularpumpe von Fig. 1,

Fig. 3

einen Querschnitt der Turbomolekularpumpe längs der in Fig. 2 gezeigten Schnittlinie A-A,

Fig. 4

eine Querschnittsansicht der Turbomolekularpumpe längs der in Fig. 2 gezeigten Schnittlinie B-B,

Fig. 5

eine Querschnittsansicht der Turbomolekularpumpe längs der in Fig. 2 gezeigten Schnittlinie C-C,

Fig. 6

einen Schnitt durch einen Teil einer Turbomolekularpumpe zur Veranschaulichung eines erfindungsgemäßen Abmessungsverhältnisses,

Fig. 7

eine Schnittansicht einer auf einer Rotorwelle befestigten Rotorscheibe zur Veranschaulichung erfindungsgemäßer Abmessungen bzw. Abmessungsverhältnisse, und

Fig. 8

einen Schnitt durch eine Rotorschaufel zur Veranschaulichung einer erfindungsgemäßen Abmessung.

The invention is described below by way of example with reference to the drawing.

Fig.1

a perspective view of a turbomolecular pump,

Fig.2

a view of the bottom of the turbomolecular pump from Fig.1 ,

Fig. 3

a cross section of the turbomolecular pump along the Fig.2 shown section line AA,

Fig.4

a cross-sectional view of the turbomolecular pump along the Fig.2 shown cutting line BB,

Fig.5

a cross-sectional view of the turbomolecular pump along the Fig.2 shown section line CC,

Fig.6

a section through a part of a turbomolecular pump to illustrate a dimensional ratio according to the invention,

Fig.7

a sectional view of a rotor disk mounted on a rotor shaft to illustrate dimensions or dimensional relationships according to the invention, and

Fig.8

a section through a rotor blade to illustrate a dimension according to the invention.

In the Fig.1 The turbomolecular pump 111 shown comprises a pump inlet 115 surrounded by an inlet flange 113, to which a recipient (not shown) can be connected in a manner known per se. The gas from the recipient can be sucked out of the recipient via the pump inlet 115 and conveyed through the pump to a pump outlet 117, to which a backing pump, such as a rotary vane pump, can be connected.

The inlet flange 113 forms the vacuum pump in the alignment according to Fig.1 the upper end of the housing 119 of the vacuum pump 111. The housing 119 comprises a lower part 121, on which an electronics housing 123 is arranged on the side. Electrical and/or electronic components of the vacuum pump 111 are housed in the electronics housing 123, e.g. for operating an electric motor 125 arranged in the vacuum pump (see also Fig. 3 ). Several connections 127 for accessories are provided on the electronics housing 123. In addition, a data interface 129, e.g. according to the RS485 standard, and a power supply connection 131 are arranged on the electronics housing 123.

There are also turbomolecular pumps that do not have such an attached electronics housing, but are connected to external drive electronics.

A flood inlet 133, in particular in the form of a flood valve, is provided on the housing 119 of the turbomolecular pump 111, via which the vacuum pump 111 can be flooded. In the area of the lower part 121, a sealing gas connection 135, which is also referred to as a purge gas connection, is also arranged, via which purge gas can be fed to protect the electric motor 125 (see e.g. Fig.3 ) can be admitted into the motor compartment 137, in which the electric motor 125 in the vacuum pump 111 is housed, before the gas delivered by the pump.

In the lower part 121, two coolant connections 139 are also arranged, one of the coolant connections being provided as an inlet and the other coolant connection as an outlet for coolant that can be fed into the vacuum pump for cooling purposes. Other existing turbomolecular vacuum pumps (not shown) are operated exclusively with air cooling.

The lower side 141 of the vacuum pump can serve as a base so that the vacuum pump 111 can be operated standing on the underside 141. The vacuum pump 111 can also be attached to a recipient via the inlet flange 113 and thus operated in a hanging position. In addition, the vacuum pump 111 can be designed in such a way that it can also be put into operation when it is aligned in a different way than in Fig.1 is shown. It is also possible to realize embodiments of the vacuum pump in which the underside 141 is not arranged facing downwards, but to the side or facing upwards. In principle, any angle is possible.

Other existing turbomolecular vacuum pumps (not shown), which are particularly larger than the pump shown here, cannot be operated in an upright position.

On the underside 141, which is in Fig.2 As shown, various screws 143 are arranged, by means of which components of the vacuum pump (not further specified here) are fastened to one another. For example, a bearing cover 145 is fastened to the underside 141.

Mounting holes 147 are also arranged on the underside 141, via which the pump 111 can be attached to a support surface, for example. This is the case with other existing turbomolecular vacuum pumps (not shown), which are particularly larger than the pump shown here, are not possible.

In the Figures 2 to 5 a coolant line 148 is shown in which the coolant introduced and discharged via the coolant connections 139 can circulate.

As the sectional views of the Figures 3 to 5 show, the vacuum pump comprises several process gas pumping stages for conveying the process gas present at the pump inlet 115 to the pump outlet 117.

A rotor 149 is arranged in the housing 119 and has a rotor shaft 153 rotatable about a rotation axis 151.

The turbomolecular pump 111 comprises several turbomolecular pump stages connected in series with a pumping effect, with several radial rotor disks 155 attached to the rotor shaft 153 and stator disks 157 arranged between the rotor disks 155 and fixed in the housing 119. A rotor disk 155 and an adjacent stator disk 157 each form a turbomolecular pump stage. The stator disks 157 are held at a desired axial distance from one another by spacer rings 159.

The vacuum pump also comprises Holweck pump stages arranged one inside the other in the radial direction and connected in series to pump with one another. There are other turbomolecular vacuum pumps (not shown) that do not have Holweck pump stages.

The rotor of the Holweck pump stages comprises a rotor hub 161 arranged on the rotor shaft 153 and two cylinder-jacket-shaped Holweck rotor sleeves 163, 165 fastened to and carried by the rotor hub 161, which are arranged coaxially to the axis of rotation 151 and are nested in the radial direction. Furthermore, two cylinder-jacket-shaped Holweck stator sleeves 167, 169 are provided, which are also oriented coaxially to the rotation axis 151 and are nested in the radial direction.

The pump-active surfaces of the Holweck pump stages are formed by the lateral surfaces, i.e. by the radial inner and/or outer surfaces, of the Holweck rotor sleeves 163, 165 and the Holweck stator sleeves 167, 169. The radial inner surface of the outer Holweck stator sleeve 167 is opposite the radial outer surface of the outer Holweck rotor sleeve 163, forming a radial Holweck gap 171, and together with this forms the first Holweck pump stage following the turbomolecular pumps. The radial inner surface of the outer Holweck rotor sleeve 163 is opposite the radial outer surface of the inner Holweck stator sleeve 169, forming a radial Holweck gap 173, and together with this forms a second Holweck pump stage. The radial inner surface of the inner Holweck stator sleeve 169 lies opposite the radial outer surface of the inner Holweck rotor sleeve 165, forming a radial Holweck gap 175 and together forming the third Holweck pumping stage.

A radially extending channel can be provided at the lower end of the Holweck rotor sleeve 163, via which the radially outer Holweck gap 171 is connected to the middle Holweck gap 173. In addition, a radially extending channel can be provided at the upper end of the inner Holweck stator sleeve 169, via which the middle Holweck gap 173 is connected to the radially inner Holweck gap 175. As a result, the nested Holweck pump stages are connected in series with one another. A connecting channel 179 to the outlet 117 can also be provided at the lower end of the radially inner Holweck rotor sleeve 165.

The above-mentioned pump-active surfaces of the Holweck stator sleeves 167, 169 each have a plurality of Holweck grooves running spirally around the rotation axis 151 in the axial direction, while the opposite lateral surfaces of the Holweck rotor sleeves 163, 165 are smooth and propel the gas in the Holweck grooves for operating the vacuum pump 111.

For the rotatable mounting of the rotor shaft 153, a rolling bearing 181 is provided in the area of the pump outlet 117 and a permanent magnet bearing 183 is provided in the area of the pump inlet 115.

In the area of the roller bearing 181, a conical spray nut 185 with an outer diameter that increases towards the roller bearing 181 is provided on the rotor shaft 153. The spray nut 185 is in sliding contact with at least one scraper of a fluid reservoir. In other existing turbomolecular vacuum pumps (not shown), a spray screw can be provided instead of a spray nut. Since different designs are thus possible, the term "spray tip" is also used in this context.

The operating fluid storage comprises several absorbent disks 187 stacked on top of each other, which are impregnated with an operating fluid for the rolling bearing 181, e.g. with a lubricant.

When the vacuum pump 111 is in operation, the operating fluid is transferred by capillary action from the operating fluid reservoir via the scraper to the rotating spray nut 185 and, as a result of the centrifugal force, is conveyed along the spray nut 185 in the direction of the increasing outer diameter of the spray nut 185 to the roller bearing 181, where it fulfills a lubricating function, for example. The roller bearing 181 and the operating fluid reservoir are enclosed in the vacuum pump by a trough-shaped insert 189 and the bearing cover 145.

The permanent magnet bearing 183 comprises a rotor-side bearing half 191 and a stator-side bearing half 193, each of which comprises a ring stack of several permanent magnet rings 195, 197 stacked on top of one another in the axial direction. The ring magnets 195, 197 lie opposite one another to form a radial bearing gap 199, with the rotor-side ring magnets 195 being arranged radially on the outside and the stator-side ring magnets 197 being arranged radially on the inside. The magnetic field present in the bearing gap 199 causes magnetic repulsion forces between the ring magnets 195, 197, which cause the rotor shaft 153 to be supported radially. The rotor-side ring magnets 195 are carried by a support section 201 of the rotor shaft 153, which surrounds the ring magnets 195 on the radial outside. The stator-side ring magnets 197 are supported by a stator-side support section 203 which extends through the ring magnets 197 and is suspended from radial struts 205 of the housing 119. The rotor-side ring magnets 195 are fixed parallel to the rotation axis 151 by a cover element 207 coupled to the support section 201. The stator-side ring magnets 197 are fixed parallel to the rotation axis 151 in one direction by a fastening ring 209 connected to the support section 203 and a fastening ring 211 connected to the support section 203. A disc spring 213 can also be provided between the fastening ring 211 and the ring magnets 197.

An emergency or safety bearing 215 is provided within the magnetic bearing, which runs idle without contact during normal operation of the vacuum pump 111 and only engages when the rotor 149 is excessively radially deflected relative to the stator, in order to form a radial stop for the rotor 149, so that a collision of the rotor-side structures with the stator-side structures is prevented. The safety bearing 215 is designed as an unlubricated roller bearing and forms a radial gap with the rotor 149 and/or the stator, which causes the safety bearing 215 to be disengaged during normal pumping operation. The The radial deflection at which the safety bearing 215 engages is large enough so that the safety bearing 215 does not engage during normal operation of the vacuum pump, and at the same time small enough so that a collision of the rotor-side structures with the stator-side structures is prevented under all circumstances.

The vacuum pump 111 comprises the electric motor 125 for rotating the rotor 149. The armature of the electric motor 125 is formed by the rotor 149, whose rotor shaft 153 extends through the motor stator 217. A permanent magnet arrangement can be arranged radially on the outside or embedded in the section of the rotor shaft 153 extending through the motor stator 217. Between the motor stator 217 and the section of the rotor 149 extending through the motor stator 217 there is an intermediate space 219 which comprises a radial motor gap, via which the motor stator 217 and the permanent magnet arrangement can magnetically influence each other to transmit the drive torque.

The motor stator 217 is fixed in the housing within the motor compartment 137 provided for the electric motor 125. A sealing gas, which is also referred to as purge gas and which can be air or nitrogen, for example, can enter the motor compartment 137 via the sealing gas connection 135. The electric motor 125 can be protected from process gas, e.g. from corrosive components of the process gas, via the sealing gas. The motor compartment 137 can also be evacuated via the pump outlet 117, i.e. the vacuum pressure in the motor compartment 137 is at least approximately the vacuum pressure caused by the forevacuum pump connected to the pump outlet 117.

Between the rotor hub 161 and a wall 221 delimiting the motor compartment 137, a so-called and known labyrinth seal 223 can also be be provided, in particular in order to achieve a better sealing of the engine compartment 217 with respect to the Holweck pump stages located radially outside.

The following are based on the Fig. 6 to 8 individual aspects and embodiments, in particular certain dimensions or dimensional ratios, of a vacuum pump according to the invention are explained, which can be implemented individually or in any combination in a turbomolecular pump, for example in a turbomolecular pump as previously described with reference to the Fig. 1 to 5 In other words, a turbomolecular pump, as described in the Fig. 1 to 5 described, be designed in accordance with the invention and in particular have one or more of the dimensions and/or one or more of the dimensional ratios as described in the Fig. 6 to 8 The following are explained below. Fig. 6 to 8 merely to illustrate the dimensions or dimensional relationships and are therefore not to scale.

The turbomolecular pump according to Fig.6 comprises a turbomolecular pump stage and a Holweck pump stage. Several rotor disks 15 are attached to a rotor shaft 13, which rotates about a rotation axis 11 during operation and is mounted on the fore-vacuum side in a roller bearing 37. The roller bearing can be lubricated by a synthetic oil, as described in the introductory part of the present disclosure.

A Holweck hub 17 is also attached to the rotor shaft 13, which carries a cylindrical Holweck sleeve 18 on the outside radially. The radial outer surface of the Holweck hub 17 lies on the same radius as the radial outer surface of the Holweck sleeve 18, namely on a radius of 1/2 * DHW, ie the outer diameter of the Holweck hub 17 is DHW.

The radially outer ends 25 of the rotor blades 21 lie on a radius of 1/2 * DA, i.e. the rotor disks 15 have an outer diameter DA.

As stated in the introductory part of the present disclosure, according to one aspect of the invention, the ratio DA/DHW is at least 1.22.

To achieve a pumping effect, the rotor blades 21 of a respective rotor disk 15 interact with stator blades of a respective stator disk 29. The stator disks 29 are fastened in a manner known in principle to those skilled in the art within a housing 27 of the turbomolecular pump. To achieve a pumping effect, the Holweck sleeve 18 interacts with a radially outer Holweck stator 31 and with a radially inner Holweck stator 33, each of which is provided with a Holweck groove arrangement facing the respective lateral surface of the Holweck sleeve 18. Such a structure of individual Holweck pump stages arranged one behind the other in the flow direction of the gas to be pumped, each of which comprises a Holweck stator and an opposite lateral surface of a Holweck sleeve and is also referred to as radially nested or interleaved Holweck stages, is known in principle to those skilled in the art.

In a further embodiment of this embodiment of the invention, the rotor disks 15 and the Holweck hub 17 can be made of the aluminum alloy. In principle, it is also possible to manufacture the Holweck sleeve 18 from this aluminum alloy. Alternatively, the Holweck sleeve 18 can be made of a different material, for example a carbon fiber reinforced plastic (CFRP), as is generally known to those skilled in the art for the production of Holweck sleeves.

Fig.7 shows a rotor disk 15 which is mounted on a rotor shaft 13 of a turbomolecular pump. The rotor shaft 13 carries a high vacuum side magnetic bearing 35, of which Fig.7 two permanent magnet rings are shown. The high vacuum side magnetic bearing of a rotor shaft 13 of a turbomolecular pump is basically known to the person skilled in the art, so that it does not need to be discussed in more detail. In this regard, reference is also made to the description of a turbomolecular pump based on the Fig. 1 to 5 referred to.

The rotor disk 15 is a one-piece component that is manufactured from a starting material by milling and/or sawing. This material is preferably aluminum alloy. However, this material is not mandatory for the rotor disk 15. The dimensions and dimensional relationships explained in more detail below can also be implemented on rotor disks 15 that are not made from this aluminum alloy.

The rotor disk 15 comprises a radially inner, hollow cylindrical collar 19, via which the rotor disk 15 is fastened to the rotor shaft 13. In addition, the rotor disk 15 has a plurality of rotor blades 21, each of which is integrally connected to the collar 19 and which each extend radially outward from a blade base 23 on the collar 19 and have a free blade end 25 radially outward. A respective blade base 23 lies on a larger radius - relative to the central axis of the hollow cylindrical collar 19, which coincides with the axis of rotation 11 of the rotor shaft 13 when fastened to the rotor shaft 13 - than the radial outer surface of the collar 19. The outer diameter DB of the collar 19, which is measured between two diametrically opposite points on the radial outer surface of the collar 19, is consequently smaller than the basic outer diameter DG which is measured from blade base 23 to blade base 23 of two imaginary diametrically opposite rotor blades 21.

Furthermore, the rotor disk 15 has a rotor outer diameter DA, which is measured between two imaginary diametrically opposite blade ends 25.

The rotor shaft 13 has an outer shaft diameter DI which corresponds to the inner diameter of the collar 19 of the rotor disk 15.

As explained in the introductory part, the radial length of a respective rotor blade 21 measured from the blade base 23 to the blade end 25 represents the pumping-effective portion of the total length of the rotor blade 21, which is measured from the collar 19 to the blade end 25.

According to one aspect of the invention, the ratio (DA - DG)/(DA - DB) is at least 0.94, preferably at least 0.95, particularly preferably 0.97.

Rotor disks 15 with such a dimensional ratio can be operated at relatively high speeds, especially when they are made of aluminum alloy. This leads to a particularly pronounced increase in the pumping performance of the vacuum pump in question.

According to a further aspect of the invention, which can be combined with the aspect of the invention described above, in a turbomolecular pump according to the invention, the basic outer diameter DG is larger than the shaft outer diameter DI by a factor of at most 1.20, preferably at most 1.15, particularly preferably at most 1.10. As already mentioned, the shaft outer diameter DI corresponds to the inner diameter of the collar 19 of the rotor disk 15. In relation to the outer diameter DI of the rotor shaft 13, the collar 19 of the rotor disk 15 according to the invention is thus comparatively thin.

Rotor disks 15 with a collar 19 dimensioned in this way can be operated at relatively high speeds if they are made of the aluminum alloy.

The axial height h of the collar 19 of the rotor disk 15 is preferably in a range from 3.0 mm to 5.9 mm, in particular up to 5.49 mm.

Preferred embodiments of the rotor blades 21 relate to their blade thickness. Fig.8 illustrates how the blade thickness is defined in the context of the present disclosure. Accordingly, at a respective radial location of a rotor blade 21, the blade thickness dG is the smallest diameter of a sectional area of the rotor blade 21, which is obtained at the radial location by a cut through the rotor blade 21 running perpendicular to the radial direction.

In a preferred embodiment, the blade thickness dG at the blade base 23 is (cf. Fig.7 ) less than 9.8 mm, in particular less than 9.0 mm.

In the middle between the blade base 23 and the blade end 25 (seen in the radial direction), the blade thickness dG is preferably in the range of 0.125 mm and 2.9 mm.

Rotor disks 15 whose rotor blades 21 have the respective blade thickness dG at one or both of these radial locations can be operated at comparatively high speeds if the rotor disks 15 are made of the aluminum alloy.

List of reference symbols

11

Rotation axis

13

Rotor shaft

15

Rotor disc

17

Holweck hub

18

Holweck sleeve

19

Federation

21

Rotor blade

23

Shovel base

25

Shovel end

27

Housing

29

Stator disc

31

Holweck stator

33

Holweck stator

35

Magnetic bearings

37

roller bearing

DHH

Outer diameter Holweck sleeve

DHW

Outer diameter Holweck hub

TUE

Shaft outer diameter

THERE

Rotor outer diameter

DB

Collar outer diameter

DG

Basic outer diameter

dG

Thickness of the rotor blade

H

axial height

Claims (13)

Vacuum pump, especially turbomolecular pump, with a rotor shaft (13) rotating about a rotation axis (11) during operation, and with at least one rotor disk (15) fastened to the rotor shaft (13), which comprises a radially inner collar (19) via which the rotor disk (15) is fastened to the rotor shaft (13), and a plurality of rotor blades (21), each of which is integrally connected to the collar (19) and which each extend radially outward from a blade base (23) on the collar (19) and have a free blade end (25) radially outward, wherein the rotor disk (15) has a rotor outer diameter DA which is measured between two imaginary diametrically opposed blade ends (25), wherein the rotor disk (15) has a collar outer diameter DB which is measured between two diametrically opposite points of a radial outer surface of the collar (19), wherein the rotor disk (15) has a basic outer diameter DG which is measured from blade base (23) to blade base (23) of two imaginary diametrically opposed rotor blades (21), wherein the ratio (DA - DG)/(DA - DB) is at least 0.94, preferably at least 0.95, and at most 0.97. Vacuum pump according to claim 1, wherein the rotor shaft (13) has an outer shaft diameter DI, and where DG is greater than DI by a factor of at most 1.20, preferably at most 1.15, particularly preferably at most 1.10. Vacuum pump according to claim 1 or 2,
wherein the rotor disk (15) and/or the Holweck hub (17) and/or the Holweck sleeve (18) are made of an aluminium alloy having the following composition in weight %: Cu: 3.6 - 4.4 Mg: 1.2 - 1.4 Mn: 0.5 - 0.8 Zr: < 0.16 Ti : 0.01 - 0.05 Si < 0.21 Fe < 0.21 Zn < 0.26 other elements < 0.06, Rest aluminum. Vacuum pump according to one of the preceding claims,
wherein the rotor disk (15) has a rotor outer diameter DA which is greater than 5.0 cm, preferably in a range from 5.0 cm to 60 cm, wherein the rotor outer diameter DA is measured between two imaginary diametrically opposite blade ends (25). Vacuum pump according to one of the preceding claims, wherein the rotor disk (15) has a rotor outer diameter DA which is measured between two imaginary diametrically opposite blade ends (25), wherein the Holweck hub (17) has a Holweck outer diameter DHW which is measured between two diametrically opposite points of a radial outer surface of the Holweck hub (17), and where the rotor outer diameter DA is at least 135 mm and the Holweck outer diameter DHW must be at least 108 mm, or where the rotor outer diameter DA is 120 mm and the Holweck outer diameter DHW is 99 mm. Vacuum pump according to one of the preceding claims, wherein the rotor disk (15) has a rotor outer diameter DA which is measured between two imaginary diametrically opposite blade ends (25), wherein the vacuum pump comprises a second Holweck hub having a Holweck outer diameter DHW2 measured between two diametrically opposite points of a radial outer surface of the second Holweck hub, where the Holweck outer diameter DHW2 of the second Holweck hub is at least 91 mm, and/or wherein the rotor outer diameter DA is larger than the Holweck outer diameter DHW2 of the second Holweck hub by a factor of at least 1.40, preferably at least 1.48. Vacuum pump according to one of the preceding claims,
wherein the rotor shaft (13) has a magnetic bearing or a hybrid bearing, namely a permanent magnet bearing (35) on the high vacuum side and a rolling bearing (37) on the pre-vacuum side. Vacuum pump according to one of the preceding claims,
wherein a plurality of rotor disks (15) are fastened to the rotor shaft (13), wherein at least two rotor disks (15) differ from one another with regard to the material from which they are made, in particular wherein at least one of the rotor disks (15) is made of the aluminum alloy. Vacuum pump according to one of the preceding claims,
wherein the Holweck sleeve (18) and/or the Holweck hub (17) has or have an outer diameter DHH or DHW which is measured between two diametrically opposite points of a radial outer surface of the Holweck sleeve (18) or the Holweck hub (17) and which lies in the range of 5.0 cm to 60 cm. Vacuum pump according to one of the preceding claims,
wherein the rotor component (15, 17, 18) has an outer diameter greater than 10 cm, preferably greater than 15 cm, particularly preferably greater than 20 cm, wherein the outer diameter is measured between two diametrically opposite points, each of which lies on a radial outer surface of the rotor component (15, 17, 18). Method for operating a vacuum pump according to claim 3 or according to one of claims 4 to 10, when directly or indirectly related to claim 3,
wherein in the method the vacuum pump is operated at a speed of the rotor shaft (13) such that the maximum permissible temperature of the rotor component (15, 17, 18) is greater than 90°C, in particular greater than or equal to 98°C, particularly preferably greater than or equal to 120°C. Method according to claim 11,
wherein the vacuum pump is operated at a speed of the rotor shaft (13) such that the blade end speed of the rotor disk (15) is more than 420 m/s, preferably more than 438 m/s, preferably more than 464 m/s. Method according to claim 11 or 12,
wherein the vacuum pump is operated at a speed of the rotor shaft (13) which is more than 59,000 revolutions per minute, preferably more than 100,000 revolutions per minute, particularly preferably more than 150,000 revolutions per minute.

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