EP4390144A2 - Pompe à vide - Google Patents

Pompe à vide Download PDF

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Publication number
EP4390144A2
EP4390144A2 EP24166455.6A EP24166455A EP4390144A2 EP 4390144 A2 EP4390144 A2 EP 4390144A2 EP 24166455 A EP24166455 A EP 24166455A EP 4390144 A2 EP4390144 A2 EP 4390144A2
Authority
EP
European Patent Office
Prior art keywords
rotor
holweck
outer diameter
vacuum pump
hub
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24166455.6A
Other languages
German (de)
English (en)
Other versions
EP4390144A3 (fr
Inventor
Sönke Gilbrich
Jan Hofmann
Bernd Koci
Mirko Mekota
Thilo Wille
Michael Schweighöfer
Tobias Stoll
Bernhard Koch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pfeiffer Vacuum Technology AG
Original Assignee
Pfeiffer Vacuum Technology AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pfeiffer Vacuum Technology AG filed Critical Pfeiffer Vacuum Technology AG
Priority to EP24166455.6A priority Critical patent/EP4390144A3/fr
Priority claimed from EP24166455.6A external-priority patent/EP4390144A3/fr
Publication of EP4390144A2 publication Critical patent/EP4390144A2/fr
Publication of EP4390144A3 publication Critical patent/EP4390144A3/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
    • F04D19/042—Turbomolecular vacuum pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
    • F04D19/044—Holweck-type pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
    • F04D19/046—Combinations of two or more different types of pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/02—Selection of particular materials
    • F04D29/023—Selection of particular materials especially adapted for elastic fluid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
    • F04D29/321—Rotors specially for elastic fluids for axial flow pumps for axial flow compressors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2300/00—Materials; Properties thereof
    • F05D2300/10—Metals, alloys or intermetallic compounds
    • F05D2300/17—Alloys
    • F05D2300/173—Aluminium alloys, e.g. AlCuMgPb

Definitions

  • 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.
  • 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.
  • 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.
  • the object of the invention is to remedy this situation.
  • This aluminum alloy is also referred to below simply as “the aluminum alloy” or as “the material according to the invention”.
  • each rotor component of the vacuum pump is made from the material according to the invention.
  • this is not mandatory.
  • a Holweck pump stage 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the rotor disks are each a one-piece component which is manufactured from a starting material by milling and/or sawing.
  • 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.
  • 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.
  • the rotor disk has a rotor outer diameter DA which is measured between two imaginary diametrically opposed blade ends
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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).
  • 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".
  • 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.
  • a data interface 129 e.g. according to the RS485 standard, and a power supply connection 131 are arranged on the electronics housing 123.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • a coolant line 148 is shown in which the coolant introduced and discharged via the coolant connections 139 can circulate.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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 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.
  • 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.
  • a so-called and known labyrinth seal 223 can also 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.
  • a vacuum pump according to the invention 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
  • 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
  • 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.
  • the ratio DA/DHW is at least 1.22.
  • 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.
  • 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.
  • 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.
  • the rotor disks 15 and the Holweck hub 17 can be made of the aluminum alloy.
  • 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.
  • CFRP carbon fiber reinforced plastic
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the shaft outer diameter DI corresponds to the inner diameter of the collar 19 of the rotor disk 15.
  • 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.
  • 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.
  • 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.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Positive Displacement Air Blowers (AREA)
EP24166455.6A 2022-12-22 Pompe à vide EP4390144A3 (fr)

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EP24166455.6A EP4390144A3 (fr) 2022-12-22 Pompe à vide

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EP4390144A2 true EP4390144A2 (fr) 2024-06-26
EP4390144A3 EP4390144A3 (fr) 2024-07-10

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3650702A1 (fr) 2018-11-12 2020-05-13 Pfeiffer Vacuum Gmbh Utilisation d'une huile synthétique dans une pompe à vide et pompe à vide

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3650702A1 (fr) 2018-11-12 2020-05-13 Pfeiffer Vacuum Gmbh Utilisation d'une huile synthétique dans une pompe à vide et pompe à vide

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EP4151860A3 (fr) 2023-04-05
EP4151860A2 (fr) 2023-03-22
EP4390145A2 (fr) 2024-06-26

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