EP1256725A1 - Vacuum pump - Google Patents

Vacuum pump Download PDF

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Publication number
EP1256725A1
EP1256725A1 EP02252919A EP02252919A EP1256725A1 EP 1256725 A1 EP1256725 A1 EP 1256725A1 EP 02252919 A EP02252919 A EP 02252919A EP 02252919 A EP02252919 A EP 02252919A EP 1256725 A1 EP1256725 A1 EP 1256725A1
Authority
EP
European Patent Office
Prior art keywords
rotor
ring shape
shape groove
weight
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Withdrawn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
EP02252919A
Other languages
German (de)
English (en)
French (fr)
Inventor
Yoshihiro c/o Seiko Instruments Inc. Yamashita
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.)
Edwards Japan Ltd
Original Assignee
BOC Edwards Technologies Ltd
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 BOC Edwards Technologies Ltd filed Critical BOC Edwards Technologies Ltd
Publication of EP1256725A1 publication Critical patent/EP1256725A1/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Withdrawn legal-status Critical Current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
    • 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
    • F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
    • F04D29/661—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for elastic fluid pumps
    • F04D29/662—Balancing of rotors

Definitions

  • the present invention relates to a vacuum pump used for a semiconductor manufacturing apparatus, and particularly, to a structure for catching eccentric balance of a rotor thereof.
  • a vacuum pump such as a turbo molecular pump is employed as means for exhausting gas in a chamber in such a step that processes are performed in a process chamber (hereinafter, referred to as "chamber") of high vacuum, such as a dry etching step of semiconductor manufacturing process or a CVD process.
  • FIG. 5 shows a conventional basic structure of this kind of vacuum pump.
  • a pump case 1 of a vacuum pump shown in Fig. 5 is provided with a gas inlet port 2 at the upper surface and an exhaust pipe that serves as an exhaust port 3 at one side portion of the lower portion, is formed in a cylindrical-shape and is attached to a base 1-1.
  • the bottom portion of the base 1-1 is covered with an end plate 4, and a stator column 5 is provided so as to be erected at the center portion of an internal bottom surface thereof.
  • a rotor shaft 7 is rotatably bored through an upper ball bearing 6 and a lower ball bearing 6 at the center of the stator column 5.
  • a driving motor 8 is arranged inside the stator column 5.
  • the driving motor 8 has a structure in which a stator element 8a is disposed inside the stator column 5 and a rotator element 8b is disposed on the rotor shaft 8, and it is structured such that the rotor shaft 7 is rotated about the shaft.
  • the rotor blades 10 are integrally disposed with the rotor 9, to thereby be integrally provided with the upper portion side outer circumferential surface of the rotor 9. Further, the rotor blades 10 can be integrally rotated with the rotor 9. However, the stator blades 11 are positioned and arranged between the upper stage and the lower stage of the rotor blades 10, 10 through a spacer 11a positioned at the upper portion side inner wall of the pump case 1. Further, the stator blades 11 are attached and fixed to the inner wall side of the pump case 1.
  • a fixed screw stator 12 is arranged at the position opposing the lower portion side outer circumferential surface of the rotor 9.
  • the screw stator 12 is formed in a cylindrical-shape so that the entire shape thereof surrounds the lower portion side outer circumferential surface of the rotor 9, and integrally attached and fixed to the base 1-1. Note that a thread groove is formed inside the screw stator 12, that is, at the surface side opposing the rotor 9.
  • the vacuum pump shown in Fig. 5 is employed as means for exhausting gas in the chamber 14 as described above. However, in this used state, the vacuum pump shown in Fig. 5 is attached and fixed to the lower surface side opening portion of the chamber 14.
  • an auxiliary pump (not shown) connected to the gas exhaust port 3 is operated to cause the inside of the chamber 14 to enter the vacuum state of some degrees. Thereafter, the driving motor 8 is operated to rotate the rotor 9 and the rotor blades 10 at high speed integrated with the rotor shaft 7.
  • the rotor blade 10 of the uppermost stage rotating at high speed imparts downward momentum to gas molecules entered from the gas inlet port 2.
  • the gas molecule including the downward momentum is guided to the stator blade 11 and sent into the side of the rotor blade 10 of the next lower stage.
  • the above momentum impartment to a gas molecule and the sending operation are repeated in a lot of stages.
  • the gas molecule of the side of the gas inlet port 2 is sequentially moved to the inside of the screw stator 12 of the lower portion side of the rotor 9.
  • the exhausting operation of the gas molecule is caused due to interaction between the rotating rotor blades 10 and the fixed stator blades 11.
  • the gas molecule which has reached the screw stator 12 of the lower portion side of the rotor 9 through the above described gas molecule exhausting operation, is compressed by interaction between the rotating rotor 9 and the thread groove formed inside the screw stator 12, and is moved to the side of the gas exhaust port 3, and then is exhausted to the exterior through the auxiliary pump (not shown) from the gas exhaust port 3.
  • the vacuum pump having the above described structure, it is capable of catching balance thereof while a rotation body composed of a rotor 9 and rotor blades 10 rotates at high speed in the pump assembling and manufacturing steps.
  • Such methods for catching the balance include: 1) a method for partially cutting the outside or the inside of the rotor 9 with a drill or a router; and 2) a method for adding a weight to the outside or the inside of the rotor 9 with an adhesive or the like.
  • the conventional vacuum pump shown in Fig. 5 is designed such that the described above balancing of the rotor 9 is conducted at two positions of the upper portion and the lower portion of the rotor 9.
  • the lower portion side of the rotor 9 has a larger diameter and larger centrifugal force than the upper portion side of the rotor 9, resulting in having a high possibility that damage of the rotor 9 is caused due to the hole, cut for catching the balance at the lower portion side of the rotor 9, in the balancing structure of the cut method shown in the above 1).
  • the present invention is made for solving the above described problems and an object of the present invention is to provide a vacuum pump having a small possibility of causing damage of a rotor, excellent in working efficiency of the balancing of the rotor, and capable of keeping the balance during a long period of time.
  • a pump case forming an inlet port at an upper surface; a cylinder-type rotor provided rotatably in the pump case; rotor blades provided integrally with the outer circumferential surface of the rotor; stator blades positioned and arranged between the rotor blades or at the outside thereof; a driving motor for rotating the rotor; and a ring shape groove formed at the internal surface of the lower portion side of the rotor along the circumferential direction thereof, in which a weight for catching the balance of the rotor is fit and attached.
  • the balancing structure of the rotor is different from the conventional structure of attaching the weight which is conducted only with an adhesive . It is structured such that this kind of weight is fit in and attached to the ring shape groove of the rotor, thereby preventing the weight from easily falling off from the rotor, being capable of keeping the balance of the rotor during a long period of time, and being excellent in working efficiency of the balancing of the rotor.
  • the present invention is characterized in that the ring shape groove forms a dovetail groove in which the weight is press fit. According to such a structure, the weight that is fitted in and attached to the dovetail groove is subjected to prevention of slip out by a reverse taper action with respect to the slip out direction thereof, thereby being capable of holding the weight at the attachment position more securely.
  • the present invention is characterized in that the internal surface of the rotor, from the lower portion opening end of the rotor to the ring shape groove, is cut to provide a cut out portion formed thereby.
  • the rotor internal diameter of the ring shape groove lower portion side is enlarged due to the cut out portion. Therefore, when the balance of the rotor is caught in the pump assembling and manufacturing steps, a finger is directly put inside this rotor, and thus the weight for catching the balance can be fit in and attached to the ring shape groove while the rotor remains set in an inspection device for catching the balance. In this concern, the working efficiency in the balancing of the rotor becomes more excellent.
  • the present invention is characterized in that the plurality of ring shape grooves are provided in a vertical direction of the rotor. According to the structure, one large ring shape groove can be divided into a plurality of small ring shape grooves and arranged. Therefore, the weight is attached to and fit in more positions as compared with the case of forming one large ring shape groove. As a result, the number of weights having the same weight is increased, thereby being capable of adapting to the large imbalance.
  • the present invention is characterized in that when the weight is accommodated in a box body provided with leaf spring members on both sides thereof, and the body box including the weight is inserted and set in the ring shape groove, the leaf spring members of the body box cause an elasticity return and are pressed by the inner walls of the ring shape groove to be in contact therewith, whereby the weight together with the box body is fitted in and attached to the ring shape groove.
  • the present invention is characterized in that the leaf spring member is folded into a U-shape, a holder including pinching pieces is used, which are constituted by further folding back externally the both sides of the folded end and the weight is fixed integrally to the inner side bottom portion formed in a U-shape of the holder, and that when the holder including the weight is inserted and set in the ring shape groove, the pinching pieces of the holder cause an elasticity return to be pressed by the inner walls of the ring shape groove to be in contact therewith, whereby the weight together with the holder is fitted in and attached to the ring shape groove.
  • a ring shape groove 20 is formed at the lower portion side internal surface of the rotor 9 along the circumferential direction of the rotor.
  • the ring shape groove 20 forms a dovetail groove as shown in a partial enlarged view of Fig. 1 and is formed a little above from the lower portion opening end of the rotor 9.
  • a weight 21 is fitted in and attached to the ring shape groove 20, which is used for catching the balance during a high speed rotation of the rotor 9 in the pump assembling and manufacturing steps.
  • the present invention adapts the structure in which the ring shape groove 20 is formed in the lower portion side internal surface of the rotor 9 and the weight 21 is fitted in and attached to the ring shape groove 20, to thereby balance the rotor 9.
  • the materials applicable to the weight 21 include lead, copper, aluminum, solder material, or a high polymer elastic body mixing metal powder and the like such as a viton rubber (fluorocarbon rubber) mixed with SUS (stainless steel) powder, etc. which is consisted of hyperbaric materials, the shape of which easily causes a plastic deformation due to the appliance of pressure.
  • a viton rubber fluorocarbon rubber
  • SUS stainless steel
  • a press fitting structure may be used, in which the weight 21 is directly press fit in the ring shape groove 20 as shown in the partial enlarged view of Fig. 1.
  • a box body 50 provided with leaf spring members 50a, 50a at both sides thereof is employed to fit the weight in the ring shape groove 20 to be attached thereto as shown in Fig. 2.
  • the weight 21 is accommodated in the box body 50 so as to be integrated therewith.
  • the leaf spring members 50a, 50a are pressed from the surfaces of the both sides of the box body 50 to hold the box body 50 and then the box body 50 is inserted into the ring shape groove 20 to be set in this state.
  • the leaf spring members 50a, 50a of the box body 50 causes the elasticity return in the ring shape groove 20, and are pressed by the inner walls of the ring shape groove 20 to be in contact therewith.
  • the weight 21 integrated with the box body 50 is fitted in and attached to the ring shape groove 20.
  • stainless steel is applicable to the material of the box body 50.
  • the structure of the box body 50 and the weight 21 at the inside thereof there can be adopted the structure in which the box body 50 is made of stainless steel and the inside of the box body 50 made of stainless steel is filled with stainless steel powder and an epoxy resin to achieve solidification thereof.
  • a holder 60 having the shape as shown in Fig. 3 there can be adopted the structure in which a holder 60 having the shape as shown in Fig. 3 is employed.
  • a leaf spring member 60a is folded into a U-shape and the holder 60 has pinching pieces 60b, 60b that are obtained by further folding back externally the both folded ends.
  • the weight 21 is integrally fixed to the inner side bottom portion formed in a U-shape of the holder 60 having such shape due to a caulking process, etc.
  • the pinching pieces 60b, 60b are pressed from the surfaces of both sides of the holder 60 to hold the holder 60, and then the holder 60 is inserted into the ring shape groove 20 to be set in this state.
  • the pinching pieces 60b, 60b of the holder 60 causes the elasticity return in the ring shape groove 20, and are pressed by the inner wall of the ring shape groove 20 to be in contact therewith.
  • the weight 21 together with the holder 60 is fitted in and attached to the ring shape groove 20.
  • the box body 50 or the holder 60 can be slightly moved in the ring shape groove 20. Therefore, the setting position of the weight 21 in the ring shape groove 20 is finely adjustable with ease as compared with the structure in which the weight 21 is directly fixed to the inside of the ring shape groove 20 by press fitting, and the working efficiency of the balancing of the rotor 9 is excellent.
  • the setting position of the weight 21 is finely adjusted and thereafter the box body 50 or the holder 60 is adjunctively fixed with an adhesive.
  • the fixation with an adhesive may be omitted, if not necessary.
  • the weight 21 may be adjunctively fixed with an adhesive, if necessary.
  • an ultraviolet curing type adhesive is used as this kind of adhesive, the position of the rotor 9 is inclined in some cases so that an application portion of the adhesive is irradiated sufficiently with an ultraviolet rays.
  • the weight 21 is fixed to the ring shape groove 20 by press fitting or through the box body 50 or the holder 60, thereby preventing the weight 21 from falling off, even in this case. Further, the position of the rotor 9 can be freely set at the time of irradiation of an ultraviolet rays. Therefore, the adhesive by which the weight 21 is adjunctively fixed has a satisfactory working efficiency in its solidification.
  • the rotor 9 is set in the inspection device.
  • the rotor 9 is rotated at high speed on the inspection device, thereby specifying the eccentric load of the rotor 9 and the position thereof.
  • the weight 21 is fitted in and attached to the ring shape groove 20 on the basis of the data of the eccentric load or the position.
  • the present embodiment adopts the structure in which the internal diameter of the rotor 9 of the lower portion side of the ring shape groove 20 is enlarged by the cut out portion 9a, so that a finger is directly put inside the rotor 9 to make it possible to fit the balancing weight 21 in the ring shape groove 20 to be attached while the rotor 9 remains set in the inspection device.
  • the vacuum pump of the present embodiment even when the operation in which the data of the eccentric load of the rotor 9 and the data of the position of the rotor 9 are obtained, and the press fitting operation of the weight 21, which is conducted on basis of the above data, are repeated several times in the pump assembling and manufacturing steps, it is not necessary to remove the rotor 9 from the inspection device every time. Thus, the balancing operation of the rotor 9 can be smoothly performed.
  • the described above embodiment makes a description as to the example where one ring shape groove 20 is provided in the lower portion side internal surface of the rotor 9.
  • this kind of ring shape groove 20 there may be provided two ring shape grooves composed of two stages or more ring shape grooves in a vertical direction of the rotor 9 as shown in Fig. 4.
  • the structure including the ring shape groove 20 consisted of a plurality of stages, one large ring shape groove can be divided into a plurality of small ring shape grooves and arranged. Therefore, the number of the positions which the weight 21 is fitted in and attached to is increased as compared with the case where one large ring shape groove is formed. As a result, the number of the weights 21 having the same weight is increased, thereby being capable of adapting to the large imbalance.
  • the example using the ring shape groove 20 formed in the dovetail groove shape has been described.
  • the ring shape groove 20 is also capable of employing the ones that have the rectangular section.
  • the present invention is also applicable to the other pumps with use of rotation such as a drag pump or the like.
  • a magnetic bearing, an air bearing, or the like may be used in addition to a ball bearing as a bearing of the rotor shaft 7.
  • the present invention there is adopted the structure in which a ring shape groove is formed along a circumferential direction of the lower portion side internal surface of a rotor, and a weight for catching the balance of the rotor is fit in and attached to the ring shape groove. Therefore, the stress increased shape is not formed in the rotor unlike in the conventional method where an area of the rotor is cut away in order to balancing of the rotor through the processing. Further, the stress concentration is not caused due to the shape, either. Therefore, the maximum stress of the rotor is reduced and the damage of the rotor can be effectively avoided. Still further, the balancing structure of the rotor is different from the conventional structure in which the weight is attached only by an adhesive.
  • the present invention is structured such that this kind of weight is fit in and attached to the ring shape groove of the rotor. Therefore, the weight is not easily fallen off from the rotor and the balance of the rotor can be kept during a long period of time. Also, the working efficiency of the balancing of the rotor is excellent.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Positive Displacement Air Blowers (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP02252919A 2001-04-27 2002-04-25 Vacuum pump Withdrawn EP1256725A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2001133360A JP2002327697A (ja) 2001-04-27 2001-04-27 真空ポンプ
JP2001133360 2001-04-27

Publications (1)

Publication Number Publication Date
EP1256725A1 true EP1256725A1 (en) 2002-11-13

Family

ID=18981231

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02252919A Withdrawn EP1256725A1 (en) 2001-04-27 2002-04-25 Vacuum pump

Country Status (4)

Country Link
US (1) US20020159899A1 (ja)
EP (1) EP1256725A1 (ja)
JP (1) JP2002327697A (ja)
KR (1) KR20020084411A (ja)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013053387A1 (de) * 2011-10-12 2013-04-18 Ebm-Papst Mulfingen Gmbh & Co. Kg Wuchtgewicht für ein gebläserad
CN106246563A (zh) * 2015-06-12 2016-12-21 株式会社岛津制作所 涡轮分子泵

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003021093A (ja) * 2001-07-05 2003-01-24 Boc Edwards Technologies Ltd 真空ポンプ
JP4935509B2 (ja) * 2007-06-05 2012-05-23 株式会社島津製作所 ターボ分子ポンプ
WO2011102006A1 (ja) 2010-02-16 2011-08-25 株式会社島津製作所 真空ポンプ
JP5812766B2 (ja) * 2011-08-29 2015-11-17 ミネベア株式会社 送風機
JP7108377B2 (ja) 2017-02-08 2022-07-28 エドワーズ株式会社 真空ポンプ、真空ポンプに備わる回転部、およびアンバランス修正方法
JP6973348B2 (ja) * 2018-10-15 2021-11-24 株式会社島津製作所 真空ポンプ
TW202346719A (zh) * 2022-04-01 2023-12-01 日商埃地沃茲日本有限公司 真空泵、真空泵用旋轉體、及真空泵用平衡修正元件

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4678399A (en) * 1984-03-01 1987-07-07 Hughes Tool Company Resistant components for submersible pump stages
US5193977A (en) * 1991-11-22 1993-03-16 Don Dame Flexible membrane sealless centrifugal pump
US5536148A (en) * 1993-09-17 1996-07-16 Hitachi, Ltd. Turbo vacuum pump

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3891263T1 (de) * 1988-02-26 1990-03-15 Nikolaj Michailovic Novikov Turbomolekular-vakuumpumpe

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4678399A (en) * 1984-03-01 1987-07-07 Hughes Tool Company Resistant components for submersible pump stages
US5193977A (en) * 1991-11-22 1993-03-16 Don Dame Flexible membrane sealless centrifugal pump
US5536148A (en) * 1993-09-17 1996-07-16 Hitachi, Ltd. Turbo vacuum pump

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013053387A1 (de) * 2011-10-12 2013-04-18 Ebm-Papst Mulfingen Gmbh & Co. Kg Wuchtgewicht für ein gebläserad
US9638214B2 (en) 2011-10-12 2017-05-02 Ebm-Papst Mulfingen Gmbh & Co. Kg Balancing weight for a fan wheel
CN106246563A (zh) * 2015-06-12 2016-12-21 株式会社岛津制作所 涡轮分子泵
CN106246563B (zh) * 2015-06-12 2020-05-19 株式会社岛津制作所 涡轮分子泵

Also Published As

Publication number Publication date
JP2002327697A (ja) 2002-11-15
US20020159899A1 (en) 2002-10-31
KR20020084411A (ko) 2002-11-07

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