WO2022124240A1 - 真空ポンプ - Google Patents
真空ポンプ Download PDFInfo
- Publication number
- WO2022124240A1 WO2022124240A1 PCT/JP2021/044569 JP2021044569W WO2022124240A1 WO 2022124240 A1 WO2022124240 A1 WO 2022124240A1 JP 2021044569 W JP2021044569 W JP 2021044569W WO 2022124240 A1 WO2022124240 A1 WO 2022124240A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- stator
- vacuum pump
- peripheral surface
- rotating body
- thread groove
- Prior art date
Links
- 239000000463 material Substances 0.000 claims abstract description 23
- 230000002093 peripheral effect Effects 0.000 claims description 72
- 230000000452 restraining effect Effects 0.000 claims description 43
- 230000006866 deterioration Effects 0.000 abstract description 6
- 239000007789 gas Substances 0.000 description 32
- 229910052751 metal Inorganic materials 0.000 description 16
- 239000002184 metal Substances 0.000 description 16
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- 238000010438 heat treatment Methods 0.000 description 10
- 229910052782 aluminium Inorganic materials 0.000 description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 9
- 238000001514 detection method Methods 0.000 description 9
- 239000004065 semiconductor Substances 0.000 description 9
- 239000010935 stainless steel Substances 0.000 description 9
- 229910001220 stainless steel Inorganic materials 0.000 description 9
- 238000004804 winding Methods 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 8
- 230000007246 mechanism Effects 0.000 description 8
- 229910052742 iron Inorganic materials 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 125000006850 spacer group Chemical group 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 230000005284 excitation Effects 0.000 description 4
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 238000010926 purge Methods 0.000 description 3
- 238000011144 upstream manufacturing Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910003902 SiCl 4 Inorganic materials 0.000 description 1
- 229910001069 Ti alloy Inorganic materials 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000005459 micromachining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000012265 solid product Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000000859 sublimation Methods 0.000 description 1
- 230000008022 sublimation Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Images
Classifications
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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
- 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
- F04D19/042—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
- F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
- F04D17/08—Centrifugal pumps
- F04D17/16—Centrifugal pumps for displacing without appreciable compression
- F04D17/168—Pumps specially adapted to produce a vacuum
-
- 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
- F04D29/40—Casings; Connections of working fluid
- F04D29/52—Casings; Connections of working fluid for axial pumps
- F04D29/522—Casings; Connections of working fluid for axial pumps 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
- F04D29/40—Casings; Connections of working fluid
- F04D29/52—Casings; Connections of working fluid for axial pumps
- F04D29/54—Fluid-guiding means, e.g. diffusers
- F04D29/541—Specially adapted for elastic fluid pumps
- F04D29/545—Ducts
- F04D29/547—Ducts having a special shape in order to influence fluid flow
-
- 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
- F05D2300/50—Intrinsic material properties or characteristics
- F05D2300/502—Thermal properties
- F05D2300/5021—Expansivity
- F05D2300/50212—Expansivity dissimilar
Definitions
- the present invention relates to a vacuum pump.
- Vacuum pumps are used to create a high degree of vacuum inside these devices.
- a thread groove pump may be provided on the downstream side of a turbo molecular pump having a rotary blade and a fixed blade.
- the so-called Holbeck type threaded groove pump is composed of an outer peripheral surface of the rotating body and a stator arranged on the outer peripheral surface of the rotating body, and a thread groove is engraved on the outer peripheral surface of the rotating body or the inner peripheral surface of the stator. ..
- the vacuum pump in addition to the exhaust performance, there are requirements for specifications such as the optimum internal temperature according to various manufacturing processes in the above-mentioned semiconductor manufacturing and the like.
- specifications such as the optimum internal temperature according to various manufacturing processes in the above-mentioned semiconductor manufacturing and the like.
- it may be required to change the internal temperature setting specifications with the same pump.
- the amount of gap between the rotating body and the stator caused by the above-mentioned thermal expansion changes due to the change in the setting specifications of the internal temperature. If this gap amount is changed to be large, the exhaust performance of the thread groove pump may be deteriorated, which may cause a problem.
- the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a vacuum pump capable of effectively suppressing deterioration of performance due to thermal expansion.
- the vacuum pump according to the present invention which achieves the above object, has an exterior body provided with an intake port, a rotating body contained in the exterior body and rotatably supported, and an abbreviation arranged on the outer periphery of the rotating body.
- a cylindrical stator and a thread groove carved in at least one of the outer peripheral surface of the rotating body or the inner peripheral surface of the stator are provided, and the rotating body is rotated to take in air from the intake port side.
- a vacuum pump that exhausts gas to the outside of the exterior body, and is formed on the outer periphery of the stator with a material having a linear expansion coefficient lower than that of the material of the stator, thereby reducing radial deformation of the stator during thermal expansion. It is characterized in that a restraining means is arranged.
- the vacuum pump configured as described above has a restraining means for reducing radial deformation of the stator during thermal expansion, the gap amount between the outer peripheral surface of the rotating body and the inner peripheral surface of the stator is widened. Can be suppressed. Therefore, this vacuum pump can effectively suppress the deterioration of the performance of the thread groove pump due to thermal expansion.
- the restraining means may be arranged at the downstream end of the stator.
- the vacuum pump has a plurality of specifications having different internal temperatures, and in each of the specifications, a gap between the outer peripheral surface of the rotating body at a predetermined position in the axial direction of the vacuum pump and the inner peripheral surface of the stator.
- the amounts may be made the same by the restraining means.
- the vacuum pump can effectively maintain the performance of the thread groove pump in each specification having a different internal temperature.
- the stress acting on the stator from the restraining means at the time of thermal expansion of the stator may be set to be less than the yield stress of the material of the stator. As a result, it is possible to effectively suppress damage to the stator that is restrained by the restraining means and receives stress during thermal expansion.
- the vacuum pump according to the embodiment of the present invention is a turbo molecular pump 100 in which a rotating blade of a rotating body rotating at high speed repels gas molecules to exhaust gas.
- the turbo molecular pump 100 is used for sucking and exhausting gas from a chamber of, for example, a semiconductor manufacturing apparatus.
- FIG. 1 A vertical cross-sectional view of this turbo molecular pump 100 is shown in FIG.
- an intake port 101 is formed at the upper end of a cylindrical outer cylinder 127.
- a rotating body 103 having a plurality of rotary blades 102 (102a, 102b, 102c ...), which are turbine blades for sucking and exhausting gas, radially and multistagely formed on the peripheral portion inside the outer cylinder 127.
- a rotor shaft 113 is attached to the center of the rotating body 103, and the rotor shaft 113 is floated and supported and position-controlled in the air by, for example, a 5-axis controlled magnetic bearing.
- the rotating body 103 is generally made of a metal such as aluminum or an aluminum alloy.
- the upper radial electromagnet 104 In the upper radial electromagnet 104, four electromagnets are arranged in pairs on the X-axis and the Y-axis.
- Four upper radial sensors 107 are provided in close proximity to the upper radial electromagnet 104 and corresponding to each of the upper radial electromagnets 104.
- the upper radial sensor 107 for example, an inductance sensor having a conduction winding, an eddy current sensor, or the like is used, and the position of the rotor shaft 113 is based on the change in the inductance of the conduction winding that changes according to the position of the rotor shaft 113. Is detected.
- the upper radial sensor 107 is configured to detect the radial displacement of the rotor shaft 113, that is, the rotating body 103 fixed to the rotor shaft 113, and send it to the control device 200.
- a compensator circuit having a PID adjustment function generates an excitation control command signal of the upper radial electromagnet 104 based on a position signal detected by the upper radial sensor 107, and is shown in FIG.
- the amplifier circuit 150 (described later) excites and controls the upper radial electromagnet 104 based on this excitation control command signal, so that the upper radial position of the rotor shaft 113 is adjusted.
- the rotor shaft 113 is made of a high magnetic permeability material (iron, stainless steel, etc.) and is attracted by the magnetic force of the upper radial electromagnet 104. Such adjustment is performed independently in the X-axis direction and the Y-axis direction, respectively. Further, the lower radial electric magnet 105 and the lower radial sensor 108 are arranged in the same manner as the upper radial electric magnet 104 and the upper radial sensor 107, and the lower radial position of the rotor shaft 113 is set to the upper radial position. It is adjusted in the same way as.
- the axial electromagnets 106A and 106B are arranged so as to vertically sandwich the disc-shaped metal disk 111 provided in the lower part of the rotor shaft 113.
- the metal disk 111 is made of a high magnetic permeability material such as iron.
- An axial sensor 109 is provided to detect the axial displacement of the rotor shaft 113, and the axial position signal thereof is configured to be sent to the control device 200.
- a compensation circuit having a PID adjustment function sends an excitation control command signal for each of the axial electromagnet 106A and the axial electromagnet 106B based on the axial position signal detected by the axial sensor 109.
- the generated amplifier circuit 150 excites and controls the axial electromagnet 106A and the axial electromagnet 106B based on these excitation control command signals, so that the axial electromagnet 106A attracts the metal disk 111 upward by magnetic force.
- the axial electromagnet 106B attracts the metal disk 111 downward, and the axial position of the rotor shaft 113 is adjusted.
- control device 200 appropriately adjusts the magnetic force exerted by the axial electromagnets 106A and 106B on the metal disk 111, magnetically levitates the rotor shaft 113 in the axial direction, and holds the rotor shaft 113 in the space in a non-contact manner.
- the amplifier circuit 150 that excites and controls the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B will be described later.
- the motor 121 includes a plurality of magnetic poles arranged in a circumferential shape so as to surround the rotor shaft 113. Each magnetic pole is controlled by the control device 200 so as to rotationally drive the rotor shaft 113 via an electromagnetic force acting on the rotor shaft 113. Further, the motor 121 incorporates a rotation speed sensor such as a Hall element, a resolver, an encoder, etc. (not shown), and the rotation speed of the rotor shaft 113 is detected by the detection signal of the rotation speed sensor.
- a rotation speed sensor such as a Hall element, a resolver, an encoder, etc.
- a phase sensor (not shown) is attached near the lower radial sensor 108 to detect the phase of rotation of the rotor shaft 113.
- the position of the magnetic pole is detected by using both the detection signals of the phase sensor and the rotation speed sensor.
- a plurality of fixed wings 123 (123a, 123b, 123c %) are arranged with a slight gap between the rotary wings 102 (102a, 102b, 102c ).
- the rotary blades 102 (102a, 102b, 102c %) are formed so as to be inclined by a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transfer exhaust gas molecules downward by collision.
- the fixed wing 123 (123a, 123b, 123c %) Is composed of a metal such as aluminum, iron, stainless steel, copper, or a metal such as an alloy containing these metals as a component.
- the fixed wing 123 is also formed so as to be inclined by a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and is arranged alternately with the steps of the rotary wing 102 toward the inside of the outer cylinder 127. ing.
- the outer peripheral end of the fixed wing 123 is supported in a state of being fitted between a plurality of stacked fixed wing spacers 125 (125a, 125b, 125c ).
- the fixed wing spacer 125 is a ring-shaped member, and is composed of, for example, a metal such as aluminum, iron, stainless steel, or copper, or a metal such as an alloy containing these metals as a component.
- An outer cylinder 127 is fixed to the outer periphery of the fixed wing spacer 125 with a slight gap.
- a base portion 129 is arranged at the bottom of the outer cylinder 127.
- An exhaust port 133 is formed in the base portion 129 and communicates with the outside. The exhaust gas that has entered the intake port 101 from the chamber (vacuum chamber) side and has been transferred to the base portion 129 is sent to the exhaust port 133.
- a thread groove stator 131 (stator) is arranged between the lower portion of the fixed wing spacer 125 and the base portion 129.
- the thread groove stator 131 is a cylindrical member made of a metal such as aluminum, copper, stainless steel, iron, or an alloy containing these metals as a component, and has a plurality of spiral thread grooves 131a on the inner peripheral surface thereof. It is engraved.
- the direction of the spiral of the thread groove 131a is the direction in which the molecules of the exhaust gas are transferred toward the exhaust port 133 when the molecules of the exhaust gas move in the rotation direction of the rotating body 103.
- a cylindrical portion 102d is hung at the lowermost portion of the rotating body 103 following the rotary blades 102 (102a, 102b, 102c ).
- the outer peripheral surface of the cylindrical portion 102d is cylindrical and projects toward the inner peripheral surface of the threaded groove stator 131, and is brought close to the inner peripheral surface of the threaded groove stator 131 with a predetermined gap amount. ing.
- the exhaust gas transferred to the thread groove 131a by the rotary blade 102 and the fixed blade 123 is sent to the base portion 129 while being guided by the thread groove 131a.
- the base portion 129 is a disk-shaped member constituting the base portion of the turbo molecular pump 100, and is generally made of a metal such as iron, aluminum, or stainless steel. Since the base portion 129 physically holds the turbo molecular pump 100 and also has the function of a heat conduction path, a metal having rigidity such as iron, aluminum or copper and having high thermal conductivity is used. Is desirable.
- the temperature of the rotary blade 102 rises due to frictional heat generated when the exhaust gas comes into contact with the rotary blade 102, conduction of heat generated by the motor 121, etc., but this heat is radiation or gas of the exhaust gas. It is transmitted to the fixed wing 123 side by conduction by molecules or the like.
- the fixed wing spacers 125 are joined to each other at the outer peripheral portion, and transmit the heat received from the rotary wing 102 by the fixed wing 123 and the frictional heat generated when the exhaust gas comes into contact with the fixed wing 123 to the outside.
- the thread groove stator 131 is arranged on the outer periphery of the cylindrical portion 102d of the rotating body 103, and the thread groove 131a is engraved on the inner peripheral surface of the thread groove stator 131.
- a thread groove is carved on the outer peripheral surface of the cylindrical portion 102d, and a spacer having a cylindrical inner peripheral surface is arranged around the thread groove.
- the gas sucked from the intake port 101 is the upper radial electric magnet 104, the upper radial sensor 107, the motor 121, the lower radial electric magnet 105, the lower radial sensor 108, and the shaft.
- the electrical component is covered with a stator column 122 so that it does not invade the electrical component composed of the directional electric magnets 106A, 106B, the axial sensor 109, etc., and the inside of the stator column 122 is kept at a predetermined pressure by a purge gas. It may hang down.
- a pipe (not shown) is arranged in the base portion 129, and purge gas is introduced through this pipe.
- the introduced purge gas is sent to the exhaust port 133 through the gaps between the protective bearing 120 and the rotor shaft 113, between the rotor and the stator of the motor 121, and between the stator column 122 and the inner peripheral side cylindrical portion of the rotary blade 102.
- the turbo molecular pump 100 requires identification of a model and control based on individually adjusted unique parameters (for example, various characteristics corresponding to the model).
- the turbo molecular pump 100 includes an electronic circuit unit 141 in its main body.
- the electronic circuit unit 141 is composed of a semiconductor memory such as EEP-ROM, electronic components such as semiconductor elements for accessing the semiconductor memory, and a substrate 143 for mounting them.
- the electronic circuit portion 141 is housed in a lower portion of a rotational speed sensor (not shown) near the center of a base portion 129 constituting the lower portion of the turbo molecular pump 100, and is closed by an airtight bottom lid 145.
- some of the process gases introduced into the chamber have the property of becoming solid when the pressure becomes higher than the predetermined value or the temperature becomes lower than the predetermined value.
- the pressure of the exhaust gas is the lowest at the intake port 101 and the highest at the exhaust port 133. If the pressure rises above a predetermined value or the temperature drops below a predetermined value while the process gas is being transferred from the intake port 101 to the exhaust port 133, the process gas becomes a solid state and becomes a turbo molecule. It adheres to the inside of the pump 100 and accumulates.
- SiCl 4 when used as a process gas in an Al etching apparatus, it is a solid product (for example, at a low vacuum (760 [torr] to 10-2 [torr]) and at a low temperature (about 20 [° C.]). It can be seen from the vapor pressure curve that AlCl 3 ) is deposited and adheres to the inside of the turbo molecular pump 100. As a result, when a deposit of process gas is deposited inside the turbo molecular pump 100, this deposit narrows the pump flow path and causes the performance of the turbo molecular pump 100 to deteriorate.
- the above-mentioned product was in a state of being easily solidified and adhered in a portion where the pressure was high in the vicinity of the exhaust port 133 and the vicinity of the thread groove stator 131.
- a heater or an annular water cooling tube 149 (not shown) is wound around the outer periphery of the base portion 129 or the like, and a temperature sensor (for example, a thermistor) (for example, not shown) is embedded in the base portion 129, for example. Based on the signal of this temperature sensor, the heating of the heater and the control of cooling by the water cooling tube 149 (hereinafter referred to as TMS; Temperature Management System) are performed so as to keep the temperature of the base portion 129 at a constant high temperature (set temperature). It has been.
- TMS Temperature Management System
- one end of the electromagnet winding 151 constituting the upper radial electromagnet 104 and the like is connected to the positive electrode 171a of the power supply 171 via the transistor 161 and the other end thereof is the current detection circuit 181 and the transistor 162. It is connected to the negative electrode 171b of the power supply 171 via.
- the transistors 161 and 162 are so-called power MOSFETs, and have a structure in which a diode is connected between the source and the drain thereof.
- the cathode terminal 161a of the diode is connected to the positive electrode 171a, and the anode terminal 161b is connected to one end of the electromagnet winding 151. Further, in the transistor 162, the cathode terminal 162a of the diode is connected to the current detection circuit 181 and the anode terminal 162b is connected to the negative electrode 171b.
- the diode 165 for current regeneration its cathode terminal 165a is connected to one end of the electromagnet winding 151, and its anode terminal 165b is connected to the negative electrode 171b.
- the cathode terminal 166a is connected to the positive electrode 171a, and the anode terminal 166b is connected to the other end of the electromagnet winding 151 via the current detection circuit 181. It has become so.
- the current detection circuit 181 is composed of, for example, a hall sensor type current sensor or an electric resistance element.
- the amplifier circuit 150 configured as described above corresponds to one electromagnet. Therefore, when the magnetic bearing is controlled by 5 axes and there are a total of 10 electromagnets 104, 105, 106A, and 106B, the same amplifier circuit 150 is configured for each of the electromagnets, and 10 amplifier circuits are provided for the power supply 171. 150 are connected in parallel.
- the amplifier control circuit 191 is composed of, for example, a digital signal processor unit (hereinafter referred to as a DSP unit) (hereinafter, referred to as a DSP unit) of the control device 200, and the amplifier control circuit 191 switches on / off of the transistors 161 and 162. It has become like.
- a DSP unit digital signal processor unit
- the amplifier control circuit 191 is adapted to compare the current value detected by the current detection circuit 181 (a signal reflecting this current value is referred to as a current detection signal 191c) with a predetermined current command value. Then, based on this comparison result, the magnitude of the pulse width (pulse width time Tp1 and Tp2) generated in the control cycle Ts, which is one cycle by PWM control, is determined. As a result, the gate drive signals 191a and 191b having this pulse width are output from the amplifier control circuit 191 to the gate terminals of the transistors 161 and 162.
- a high voltage of, for example, about 50 V is used as the power supply 171 so that the current flowing through the electromagnet winding 151 can be rapidly increased (or decreased).
- a normal capacitor is normally connected between the positive electrode 171a and the negative electrode 171b of the power supply 171 for the purpose of stabilizing the power supply 171 (not shown).
- the electromagnet current iL when both the transistors 161 and 162 are turned on, the current flowing through the electromagnet winding 151 (hereinafter referred to as the electromagnet current iL) increases, and when both are turned off, the electromagnet current iL decreases.
- flywheel current when one of the transistors 161 and 162 is turned on and the other is turned off, the so-called flywheel current is maintained.
- the hysteresis loss in the amplifier circuit 150 can be reduced, and the power consumption of the entire circuit can be suppressed to a low level.
- the transistors 161 and 162 by controlling the transistors 161 and 162 in this way, it is possible to reduce high frequency noise such as harmonics generated in the turbo molecular pump 100. Further, by measuring this flywheel current with the current detection circuit 181 it becomes possible to detect the electromagnet current iL flowing through the electromagnet winding 151.
- the transistors 161 and 162 are used only once in the control cycle Ts (for example, 100 ⁇ s) for the time corresponding to the pulse width time Tp1. Turn both on. Therefore, the electromagnet current iL during this period increases from the positive electrode 171a to the negative electrode 171b toward the current value iLmax (not shown) that can be passed through the transistors 161 and 162.
- both the transistors 161 and 162 are turned off only once in the control cycle Ts for the time corresponding to the pulse width time Tp2. .. Therefore, the electromagnet current iL during this period decreases from the negative electrode 171b to the positive electrode 171a toward the current value iLmin (not shown) that can be regenerated via the diodes 165 and 166.
- the vacuum pump according to the present embodiment has a high-temperature stator 201 connected to the thread groove stator 131, a heating body 202 housed in the high-temperature stator 201, and a high-temperature stator, as shown in FIG.
- the lower outer cylinder 210 arranged on the outer periphery of the 201 is provided with the restraining means 220 arranged on the outer periphery of the thread groove stator 131.
- the upper end side of the lower outer cylinder 210 is connected to the lower side of the outer cylinder 127, and the lower end side is connected to the upper side of the base portion 129.
- the outer cylinder 127, the lower outer cylinder 210, and the base portion 129 constitute an exterior body 203 that rotatably contains the rotating body 103.
- the high temperature stator 201 has a substantially cylindrical shape, the lower end side is connected to the base portion 129 via an O-ring, and the upper end side is connected to the inside of the lower outer cylinder 210 via an O-ring.
- the high temperature stator 201 in which the heating body 202 is arranged may not have a structure separate from the thread groove stator 131 but may have a structure integrated with the thread groove stator 131.
- the heating body 202 is inserted and fixed inside the high temperature stator 201.
- the heating body 202 is connected to a heating body control device (not shown), and the heating body control device controls the temperature of the heating body 202.
- the heating body 202 is appropriately adjusted so as to maintain the temperatures of the high temperature stator 201 and the thread groove stator 131 at predetermined values higher than the temperature of the rotating body 103.
- the thread groove stator 131 has a substantially cylindrical shape, and has a stator upper end portion 131b located on the upstream side and a stator lower end portion 131c located on the downstream side.
- the thread groove stator 131 is connected to the inside of the high temperature stator 201 at the upper end portion 131b of the stator. Further, a space serving as a gas flow path to the exhaust port 133 is provided on the outer peripheral side of the thread groove stator 131, and the thread groove stator 131 is provided from the stator upper end portion 131b so that the stator lower end portion 131c becomes a free end. It extends downward.
- the lower end portion 131c of the stator is separated from the outer peripheral surface of the cylindrical portion 102d of the rotating body 103 arranged on the inner peripheral side with a gap, and is separated from the inner peripheral surface of the high temperature stator 201 arranged on the outer peripheral side. Away.
- the outer peripheral surface of the lower end portion 131c of the stator does not face the inner peripheral surface of the high temperature stator 201, but other members (for example, the outer body 203 such as the outer cylinder 127 and the lower outer cylinder 210, and the outer body 203). It may face the inner peripheral surface of (another stator member) arranged inside the.
- the restraining means 220 has a cylindrical shape and is arranged on the outer periphery of the thread groove stator 131.
- the inner peripheral surface of the restraining means 220 is in contact with the outer peripheral surface of the lower end portion 131c of the stator.
- the restraining means 220 is fixed by press-fitting, for example, the lower end portion 131c of the stator.
- the method of fixing the restraining means 220 to the thread groove stator 131 is not particularly limited, and may be fixed by, for example, bolts.
- the outer peripheral surface of the restraining means 220 faces the inner peripheral surface of the high temperature stator 201 with a gap.
- the inner peripheral surface and the outer peripheral surface of the restraining means 220 on the axial side are chamfered with a curved surface or a flat surface.
- the axial direction of the restraining means 220 having a cylindrical shape is a direction connecting the centers of the two openings of the cylinder.
- the axial length and radial wall thickness of the restraining means 220 are not particularly limited.
- the restraining means 220 is formed of a material having a coefficient of linear expansion lower than that of the material of the thread groove stator 131.
- the material of the thread groove stator 131 is aluminum or an aluminum alloy
- stainless steel, ceramics, titanium alloy or the like can be preferably used as the material of the restraining means 220.
- the stainless steel is not particularly limited, but for example, SUS400 series such as SUS403, SUS405, SUS410, and SUS430 can be preferably used.
- the outer peripheral surface of the restraining means 220 does not face the inner peripheral surface of the high temperature stator 201, but the outer peripheral body 203 such as the outer cylinder 127 or the lower outer cylinder 210 or the outer body 203 of other members (for example, the outer cylinder 127 or the lower outer cylinder 210). It may face the inner peripheral surface of another stator member (which is arranged inside).
- the shape of the restraining means 220 is a cylindrical shape having a constant inner diameter and outer diameter in the axial direction, but is not limited thereto. For example, the outer diameter of the restraining means 220 does not have to be constant in the axial direction.
- the exhaust gas taken in from the intake port 101 is transferred to the downstream side by the turbo molecular pump mechanism formed by the rotating blade 102 and the stationary blade 123.
- the exhaust gas transferred to the downstream side is guided to the Holbeck type pump mechanism formed by the cylindrical portion 102d of the rotating body 103 and the thread groove stator 131, and then transferred to the exhaust port 133.
- the thread groove stator 131 and the high temperature stator 201 are heated by the heating body 202 in order to prevent the reaction products generated in semiconductor manufacturing and the like from accumulating.
- the cylindrical portion 102d and the threaded groove stator 131 are made of a material having a coefficient of linear expansion of the same degree
- the threaded groove stator 131 having a temperature higher than that of the cylindrical portion 102d is the cylindrical portion 102d without the restraining means 220. Thermal expansion is greater than.
- the cylindrical portion 102d and the thread groove stator 131 are made of aluminum, and the restraining means 220 is made of stainless steel.
- the thread groove stator 131 is larger than the cylindrical portion 102d and easily expands thermally even when the diameter expansion amount is taken into consideration. Therefore, when the restraining means 220 is not provided, the gap amount between the outer peripheral surface of the cylindrical portion 102d and the inner peripheral surface of the thread groove stator 131 is widened, and the performance of the thread groove pump is deteriorated.
- a restraining means 220 formed of a material having a coefficient of linear expansion lower than that of the material of the threaded groove stator 131 is arranged.
- the thread groove stator 131 is suppressed from thermal expansion in the radial direction by the restraining means 220. Therefore, the gap amount between the outer peripheral surface of the cylindrical portion 102d through which the gas flows and the inner peripheral surface of the thread groove stator 131 can be appropriately maintained.
- the restraining means 220 Since the restraining means 220 has a cylindrical shape, it has a uniform structure in the circumferential direction, and its outer periphery is separated from other members. Therefore, since the restraining means 220 can restrain the thread groove stator 131 with a uniform restraining force in the circumferential direction, the gap amount between the outer peripheral surface of the cylindrical portion 102d and the inner peripheral surface of the thread groove stator 131 is set to an appropriate amount. Can be maintained uniformly.
- This vacuum pump may have multiple specifications with different internal temperatures.
- the internal temperature of the Holbeck type pump mechanism of the vacuum pump is set in the range of 70 ° C. to 200 ° C.
- the internal temperature in the Holbeck type pump mechanism is the temperature of the parts (cylindrical portion 102d and / or thread groove stator 131) constituting the pump mechanism.
- the gap amount between the outer peripheral surface of the cylindrical portion 102d of the vacuum pump and the inner peripheral surface of the thread groove stator 131 in each specification (internal temperature) is preferably within an appropriate range, and more preferably substantially constant. And more preferably constant.
- the restraining means 220 is provided on the outer periphery of the threaded groove stator 131, so that the gap between the outer peripheral surface of the cylindrical portion 102d and the inner peripheral surface of the threaded groove stator 131 It is preferable that the amount does not change much.
- the appropriate gap amount between the outer peripheral surface of the cylindrical portion 102d and the inner peripheral surface of the thread groove stator 131 is, for example, 200 to 1000 ⁇ m.
- the amount of gap between the outer peripheral surface of the cylindrical portion 102d and the inner peripheral surface of the thread groove stator 131 may change during one rotation due to the runout caused by the rotation of the rotating body 103.
- the vacuum pump issues a warning sound when the measured runout of the rotating body 103 reaches a threshold value (for example, 100 ⁇ m) so that the outer peripheral surface of the cylindrical portion 102d and the inner peripheral surface of the thread groove stator 131 do not come into contact with each other. May be good.
- a threshold value for example, 100 ⁇ m
- the thread groove stator 131 When the temperature of the thread groove stator 131 and the restraint means 220 rises, the thread groove stator 131 receives stress from the restraint means 220.
- the thread groove stator 131 may be a material that is more easily deformed than stainless steel or the like, such as aluminum or an aluminum alloy. Therefore, the stress acting on the threaded groove stator 131 from the restraining means 220 is preferably less than the yield stress of the material of the threaded groove stator 131 so that the threaded groove stator 131 is not plastically deformed.
- the stress acting on the thread groove stator 131 from the restraining means 220 in each specification is increased. It is preferably less than the breakdown stress of the material of the thread groove stator 131. That is, even if the internal temperature changes within the range of the specifications, the stress acting on the thread groove stator 131 is always less than the yield stress, and the plastic deformation of the thread groove stator 131 can be suppressed.
- the vacuum pump according to the present embodiment has an outer body 203 provided with an intake port 101, a rotating body 103 contained in the outer body 203 and rotatably supported, and an outer periphery of the rotating body 103.
- a substantially cylindrical threaded groove stator 131 arranged and a threaded groove 131a engraved on at least one of the outer peripheral surface of the rotating body 103 or the inner peripheral surface of the threaded groove stator 131 are provided, and the rotating body 103 is rotated.
- the vacuum pump As a result, it is a vacuum pump that exhausts the gas taken in from the intake port 101 side to the outside of the exterior body 203, and is formed on the outer periphery of the threaded groove stator 131 with a material having a lower linear expansion coefficient than the material of the threaded groove stator 131.
- a restraining means 220 for reducing radial deformation of the threaded groove stator 131 during thermal expansion is provided.
- the vacuum pump has a restraining means 220 that reduces radial deformation of the thread groove stator 131 during thermal expansion, so that there is a gap between the outer peripheral surface of the rotating body 103 and the inner peripheral surface of the thread groove stator 131. It is possible to suppress the spread of the amount. Therefore, this vacuum pump can effectively suppress the deterioration of the performance of the thread groove pump due to thermal expansion.
- the restraining means 220 is arranged at the downstream end of the thread groove stator 131.
- thermal expansion in the radial direction of the downstream end of the thread groove stator 131 whose outer peripheral surface is not fixed on the downstream side can be suppressed, and deterioration of the performance of the thread groove pump can be effectively suppressed.
- the vacuum pump has a plurality of specifications having different internal temperatures, and in each specification, the gap amount between the outer peripheral surface of the rotating body 103 at a predetermined position in the axial direction of the vacuum pump and the inner peripheral surface of the thread groove stator 131. May be the same by the restraint means 220. As a result, the vacuum pump can effectively maintain the performance of the thread groove pump in each specification having a different internal temperature.
- the stress acting on the thread groove stator 131 from the restraining means 220 at the time of thermal expansion of the thread groove stator 131 may be set to be less than the yield stress of the material of the thread groove stator 131. As a result, it is possible to effectively prevent the thread groove stator 131, which is restrained by the restraining means 220 and receives stress during thermal expansion, from being damaged.
- the outer peripheral surface of the cylindrical portion 102d is smooth and the thread groove is formed on the inner peripheral surface of the thread groove stator 131, but the thread groove is formed on the outer peripheral surface of the cylindrical portion 102d.
- the inner peripheral surface of the outer stator may be smooth.
- the thread groove pump on the downstream side of the vacuum pump may be formed by combining a sigburn type pump mechanism and a Holbeck type pump mechanism.
- the thread groove stator 131 may have a structure connected to the high temperature stator 201 at the downstream end portion or a structure connected at the central portion in the flow direction. Therefore, the restraining means 220 may be arranged not at the upstream end of the thread groove stator 131 but at the upstream end or the central portion in the flow direction.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Non-Positive Displacement Air Blowers (AREA)
Abstract
Description
101 吸気口
102d 円筒部
103 回転体
131 ねじ溝ステータ(ステータ)
131a ねじ溝
131b ステータ上端部
131c ステータ下端部
133 排気口
201 高温ステータ
202 加熱体
203 外装体
220 拘束手段
Claims (4)
- 吸気口が設けられた外装体と、
前記外装体に内包され、回転自在に支持された回転体と、
前記回転体の外周に配置された略円筒状のステータと、
前記回転体の外周面または前記ステータの内周面の少なくとも一方に刻設されたねじ溝と、を備え、前記回転体を回転させることにより、前記吸気口側から吸気した気体を前記外装体外へ排気する真空ポンプであって、
前記ステータの外周に、前記ステータの材料よりも線膨張係数の低い材料で形成され、前記ステータの熱膨張時の径方向の変形を低減させる拘束手段が配設されることを特徴とする真空ポンプ。 - 前記拘束手段は、前記ステータの下流側の端部に配設されることを特徴とする請求項1に記載の真空ポンプ。
- 前記真空ポンプは、内部温度が異なる複数の仕様を有し、
各々の前記仕様における、前記真空ポンプの軸方向の所定位置の前記回転体の前記外周面と前記ステータの前記内周面とのギャップ量は、前記拘束手段によって同じになるようにされたことを特徴とする請求項1また2に記載の真空ポンプ。 - 前記ステータの熱膨張時における、前記拘束手段から前記ステータに作用する応力は、前記ステータの材料の降伏応力未満となるようにされたことを特徴とする請求項1~3のいずれか1項に記載の真空ポンプ。
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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US18/252,286 US20240011496A1 (en) | 2020-12-11 | 2021-12-03 | Vacuum pump |
CN202180075707.7A CN116457582A (zh) | 2020-12-11 | 2021-12-03 | 真空泵 |
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JP2020205721A JP2022092802A (ja) | 2020-12-11 | 2020-12-11 | 真空ポンプ |
JP2020-205721 | 2020-12-11 |
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WO2022124240A1 true WO2022124240A1 (ja) | 2022-06-16 |
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PCT/JP2021/044569 WO2022124240A1 (ja) | 2020-12-11 | 2021-12-03 | 真空ポンプ |
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US (1) | US20240011496A1 (ja) |
JP (1) | JP2022092802A (ja) |
CN (1) | CN116457582A (ja) |
WO (1) | WO2022124240A1 (ja) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS58193932A (ja) * | 1982-05-07 | 1983-11-11 | Hitachi Ltd | 回転体の締結装置 |
JPS63154891A (ja) * | 1986-12-18 | 1988-06-28 | Osaka Shinku Kiki Seisakusho:Kk | ねじ溝式真空ポンプ |
WO2015122215A1 (ja) * | 2014-02-14 | 2015-08-20 | エドワーズ株式会社 | 真空ポンプ、及びこの真空ポンプに用いられる断熱スペーサ |
WO2017086135A1 (ja) * | 2015-11-16 | 2017-05-26 | エドワーズ株式会社 | 真空ポンプ |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10677260B2 (en) * | 2017-02-21 | 2020-06-09 | General Electric Company | Turbine engine and method of manufacturing |
-
2020
- 2020-12-11 JP JP2020205721A patent/JP2022092802A/ja active Pending
-
2021
- 2021-12-03 CN CN202180075707.7A patent/CN116457582A/zh active Pending
- 2021-12-03 US US18/252,286 patent/US20240011496A1/en active Pending
- 2021-12-03 WO PCT/JP2021/044569 patent/WO2022124240A1/ja active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS58193932A (ja) * | 1982-05-07 | 1983-11-11 | Hitachi Ltd | 回転体の締結装置 |
JPS63154891A (ja) * | 1986-12-18 | 1988-06-28 | Osaka Shinku Kiki Seisakusho:Kk | ねじ溝式真空ポンプ |
WO2015122215A1 (ja) * | 2014-02-14 | 2015-08-20 | エドワーズ株式会社 | 真空ポンプ、及びこの真空ポンプに用いられる断熱スペーサ |
WO2017086135A1 (ja) * | 2015-11-16 | 2017-05-26 | エドワーズ株式会社 | 真空ポンプ |
Also Published As
Publication number | Publication date |
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US20240011496A1 (en) | 2024-01-11 |
JP2022092802A (ja) | 2022-06-23 |
CN116457582A (zh) | 2023-07-18 |
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