EP1402975A1 - Method of manufacturing vacuum pump rotors, and rotors obtained thereby - Google Patents

Method of manufacturing vacuum pump rotors, and rotors obtained thereby Download PDF

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Publication number
EP1402975A1
EP1402975A1 EP20030017613 EP03017613A EP1402975A1 EP 1402975 A1 EP1402975 A1 EP 1402975A1 EP 20030017613 EP20030017613 EP 20030017613 EP 03017613 A EP03017613 A EP 03017613A EP 1402975 A1 EP1402975 A1 EP 1402975A1
Authority
EP
European Patent Office
Prior art keywords
rotor
billet
forging
rotors
turbine pump
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.)
Withdrawn
Application number
EP20030017613
Other languages
German (de)
English (en)
French (fr)
Inventor
Fausto Casaro
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.)
Varian SpA
Original Assignee
Varian SpA
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 Varian SpA filed Critical Varian SpA
Publication of EP1402975A1 publication Critical patent/EP1402975A1/en
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K1/00—Making machine elements
    • B21K1/28—Making machine elements wheels; discs
    • B21K1/36—Making machine elements wheels; discs with blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K3/00—Making engine or like machine parts not covered by sub-groups of B21K1/00; Making propellers or the like
    • B21K3/04—Making engine or like machine parts not covered by sub-groups of B21K1/00; Making propellers or the like blades, e.g. for turbines; Upsetting of blade roots

Definitions

  • the present invention relates to turbine pumps and more particularly to a method of manufacturing vacuum pump rotors for a turbine pump, in particular a turbomolecular pump, as well as to the rotors obtained thereby.
  • a turbine pump in particular a turbomolecular pump
  • the invention will be disclosed with special reference to the manufacture of a rotor for a turbomolecular pump, but this is not to be intended as a limitation of the applications of the invention.
  • the rotor of a turbomolecular pump comprises a group of impellers mounted onto a rotating shaft, each impeller comprising a disk equipped with a set of peripheral radial vanes.
  • the rotor rotates at peripheral speeds that can be as high as several ten thousand turns per minute.
  • the severe working conditions and the search for higher and higher performance for turbomolecular pumps, in terms of compression ratio and pumping speed, require that each impeller and the rotor in the whole be made as a structure that is robust and balanced at the same time.
  • the impeller vanes must be so shaped as to optimise the pump performance.
  • manufacturing starts from an extruded metal bar, from which cylinders are cut that are subsequently worked by different methods, such as turning, milling, electric discharge machining and so on.
  • the impeller is made by forming the blades by milling, by using an apparatus allowing simultaneous working of several disks.
  • each vane of the impeller by means of an electric discharge machining technique, as disclosed for instance in FR-A-2 570 970 and EP-A 0 426 233, the latter being in the name of the present Applicant.
  • the known manufacturing methods have some drawbacks and limitations.
  • the mechanical properties and the density of the material are not homogenous enough to ensure a long operating life of the rotors.
  • the transversal mechanical properties are far worse than the longitudinal properties.
  • the permanence time of the rotor at high temperature cannot be too long: it is of the order of a few hundred hours for a rotor made of aluminium alloy 2014 exposed in continuous manner to temperatures of the order of 130°C, with equivalent stresses (determined for instance according to the Von Mises criterion) of the order of 300 MPa.
  • the method of the invention comprises preparing an intermediate semi-finished piece, which is obtained by forging and is then finished by a conventional mechanical working.
  • the method of the invention is especially suitable for obtaining bell-shaped rotors or in general non-monolithic rotors with shaft driving into an axial bore, even if this is not to be intended in a limiting sense.
  • the invention further concerns the rotors obtained by the method starting from a forged semi-finished piece.
  • a cylindrical billet 1 is obtained by forging through an axial compression, schematised by forces P1, while preventing radial expansion through means not shown in Fig. 1, schematised by forces Pr.
  • billet 11 In case the rotor is a so-called bell-shaped rotor, starting from a bar portion, billet 11 would be first shaped into a substantially cylindrical shape by axial compression, as schematically shown in Fig. 2A and indicated by forces Pl. Subsequently an axial cavity would be formed through a punch 12, which would be forced into billet 11, while preventing the billet radial expansion by retaining it in a mould (forces Pr), as shown in Fig. 2B.
  • forces Pr forces
  • billet 11 is mechanically worked by known techniques to form the vanes, for instance by milling, turning, etc.
  • axial cavity 13 is preferably only partly formed by means of the punch by forging, the remaining part being finished by mechanical working.
  • the axial size of the cavity obtained by means of the punch is usually half the total height of the billet after forging.
  • the aluminium alloys commonly used to manufacture turbomolecular pump rotors are alloys 2014 (Al-Cu alloy) and 7075 (Al-Zn alloy) in the form of extruded bars that are then submitted to tempering and ageing.
  • alloys 2014 Al-Cu alloy
  • 7075 Al-Zn alloy
  • Forming a central bore on the bottom of the bell obtained by forging allows a further homogenisation of the mechanical properties obtained through the subsequent thermal treatment.
  • Figs. 3 and 4 show two rotors obtained by the method of the invention.
  • the solid lines show the profile of the bell-shaped billet 11 (intermediate piece) that is subsequently refined by mechanical working.
  • the dashed lines show the profile of the rotor that can be obtained by turning the forged billet.
  • the prior art rotors are obtained from extruded bars, in which the above mentioned strength parameters considerably change when passing from the centre to the periphery of the bar, and depending on whether the corresponding cylindrical tensile test specimens are obtained with their axes in the extrusion direction (axis parallel with the bar axis) or perpendicular to such direction (in radial or tangential direction in the bar).
  • the Applicant has established that, by manufacturing the billets by forging, the values of R, A and R0.2 become considerably constant, both in the different points of the piece and in the different directions in which the test specimens for measuring said parameters are obtained.
  • the rotors obtained by the method of the invention exhibit a homogenisation of the material density.
  • This feature is of particular interest in parts that have to rotate at high speed (with tangential speeds of the order of 300-400 m/sec), as is the case for rotors of turbomolecular pumps.
  • the non-uniform density would lead to a rotor mass that is not distributed in axially symmetrical manner, with negative effects on the balancing.
  • a further advantage of the method of the invention is that, by means of the forging, a rotor is obtained that is much closer to the final shape, so that a smaller turning or other mechanical working is required to obtain the finished product.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Positive Displacement Air Blowers (AREA)
  • Forging (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP20030017613 2002-09-06 2003-08-11 Method of manufacturing vacuum pump rotors, and rotors obtained thereby Withdrawn EP1402975A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTO20020770 2002-09-06
IT000770A ITTO20020770A1 (it) 2002-09-06 2002-09-06 Metod0 per fabbricare rotori di pompe da vuoto e prodotti

Publications (1)

Publication Number Publication Date
EP1402975A1 true EP1402975A1 (en) 2004-03-31

Family

ID=31972229

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20030017613 Withdrawn EP1402975A1 (en) 2002-09-06 2003-08-11 Method of manufacturing vacuum pump rotors, and rotors obtained thereby

Country Status (4)

Country Link
US (1) US20040175261A1 (https=)
EP (1) EP1402975A1 (https=)
JP (1) JP2004263687A (https=)
IT (1) ITTO20020770A1 (https=)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101432525A (zh) * 2006-04-29 2009-05-13 欧瑞康莱宝真空公司 涡轮分子泵的转子或定子
DE102012222230A1 (de) * 2012-12-04 2014-06-05 Pfeiffer Vacuum Gmbh Vakuumpumpe
KR102270864B1 (ko) 2017-04-19 2021-07-01 주식회사 엘지에너지솔루션 리튬 이차전지용 음극, 이를 포함하는 리튬 이차전지, 및 이의 제조 방법
CN112719813B (zh) * 2020-12-31 2024-06-18 宝鼎重工有限公司 一种轴套类产品转子中心的精加工方法
JP7390408B2 (ja) * 2022-01-13 2023-12-01 エドワーズ株式会社 真空ポンプ、真空ポンプ用回転体、及び真空ポンプの製造方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2080641A (en) * 1934-06-22 1937-05-18 Aluminum Co Of America Method of producing locomotive connecting rods
JPS584323A (ja) * 1981-06-26 1983-01-11 Osaka Shinku Kiki Seisakusho:Kk 動翼付ロ−タ−の成形法
JPH02136595A (ja) * 1988-11-16 1990-05-25 Anelva Corp 真空ポンプ
EP0818548A1 (en) * 1996-07-10 1998-01-14 Mitsubishi Heavy Industries, Ltd. Aluminum alloy impeller and manufacturing method of the same
JP2000197943A (ja) * 1998-12-28 2000-07-18 Furukawa Electric Co Ltd:The 鍛造品回転体及びその製造方法
JP2000254754A (ja) * 1999-03-08 2000-09-19 Showa Denko Kk アルミニウム合金製ローター素材の製造方法およびアルミニウム合金製ローター素材
JP2002285306A (ja) * 2001-03-27 2002-10-03 Kobe Steel Ltd アルミニウム合金製ロータ材の製造方法

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2102679C2 (de) * 1971-01-21 1982-12-30 Papst-Motoren GmbH & Co KG, 7742 St Georgen Elektro-Kleinmotor für einen Lüfter
US4789410A (en) * 1987-03-03 1988-12-06 United Technologies Corporation Method for heat treating and quenching complex metal components using salt baths
US4860567A (en) * 1987-12-21 1989-08-29 United Technologies Corporation Ring forging process
IT1238201B (it) * 1989-11-03 1993-07-09 Varian Spa Metodo di fabbricazione mediante elettroerosione di una girante o di un rotore a una o piu' giranti di una turbopompa, particolarmente di una pompa turbomolecolare, e prodotti cosi' ottenuti.
US5507617A (en) * 1993-08-04 1996-04-16 General Signal Corporation Regenerative turbine pump having low horsepower requirements under variable flow continuous operation
JP4003147B2 (ja) * 1998-02-16 2007-11-07 株式会社ヴァレオサーマルシステムズ ロータの製造方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2080641A (en) * 1934-06-22 1937-05-18 Aluminum Co Of America Method of producing locomotive connecting rods
JPS584323A (ja) * 1981-06-26 1983-01-11 Osaka Shinku Kiki Seisakusho:Kk 動翼付ロ−タ−の成形法
JPH02136595A (ja) * 1988-11-16 1990-05-25 Anelva Corp 真空ポンプ
EP0818548A1 (en) * 1996-07-10 1998-01-14 Mitsubishi Heavy Industries, Ltd. Aluminum alloy impeller and manufacturing method of the same
JP2000197943A (ja) * 1998-12-28 2000-07-18 Furukawa Electric Co Ltd:The 鍛造品回転体及びその製造方法
JP2000254754A (ja) * 1999-03-08 2000-09-19 Showa Denko Kk アルミニウム合金製ローター素材の製造方法およびアルミニウム合金製ローター素材
JP2002285306A (ja) * 2001-03-27 2002-10-03 Kobe Steel Ltd アルミニウム合金製ロータ材の製造方法

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 0070, no. 79 (M - 204) 31 March 1983 (1983-03-31) *
PATENT ABSTRACTS OF JAPAN vol. 0143, no. 75 (M - 1010) 14 August 1990 (1990-08-14) *
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 10 17 November 2000 (2000-11-17) *
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 12 3 January 2001 (2001-01-03) *
PATENT ABSTRACTS OF JAPAN vol. 2003, no. 02 5 February 2003 (2003-02-05) *

Also Published As

Publication number Publication date
JP2004263687A (ja) 2004-09-24
ITTO20020770A1 (it) 2004-03-07
US20040175261A1 (en) 2004-09-09

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