EP4202227A1 - Vacuum pump, fixed blade, and spacer - Google Patents
Vacuum pump, fixed blade, and spacer Download PDFInfo
- Publication number
- EP4202227A1 EP4202227A1 EP21858144.5A EP21858144A EP4202227A1 EP 4202227 A1 EP4202227 A1 EP 4202227A1 EP 21858144 A EP21858144 A EP 21858144A EP 4202227 A1 EP4202227 A1 EP 4202227A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- stator blade
- blades
- outlet port
- rim
- outer rim
- 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
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- 125000006850 spacer group Chemical group 0.000 title claims abstract description 64
- 208000016253 exhaustion Diseases 0.000 abstract description 15
- 238000010586 diagram Methods 0.000 description 42
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- 238000001514 detection method Methods 0.000 description 9
- 238000004804 winding Methods 0.000 description 9
- 238000005520 cutting process Methods 0.000 description 7
- 229910052742 iron Inorganic materials 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- 238000005266 casting Methods 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 230000005284 excitation Effects 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- 229910001220 stainless steel Inorganic materials 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000010926 purge Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 150000002739 metals Chemical class 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
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 229910003910 SiCl4 Inorganic materials 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- FDNAPBUWERUEDA-UHFFFAOYSA-N silicon tetrachloride Chemical compound Cl[Si](Cl)(Cl)Cl FDNAPBUWERUEDA-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000012265 solid product Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Images
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
-
- 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
- F04D29/26—Rotors specially for elastic fluids
-
- 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
- F04D29/403—Casings; Connections of working fluid 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
- F04D29/542—Bladed diffusers
-
- 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
Definitions
- the present invention relates to a vacuum pump, a stator blade, and a spacer, and more particularly to a structure for improving exhaustion efficiency of a vacuum pump.
- a vacuum pumps such as a turbomolecular pump that exhausts gas by rotating at high speed a rotor potion (a shaft and a rotor) and a rotating portion, which includes rotor blades and a rotating cylinder, in a casing having an inlet port and an outlet port.
- Such a vacuum pump exhausts gas through interaction between rotor blades in multiple stages rotating at high speed and stator blades in multiple stages fixed to the casing.
- a stator blade 123 used in this vacuum pump includes a plurality of blades 550, an inner rim 600, which holds and fixes inner sides (sides corresponding to the rotor portion when installed) of the plurality of blades 550, and an outer rim 700, which holds and fixes outer sides (sides corresponding to the casing when installed) of the blades 550.
- FIG. 31 is a partially enlarged view of a circle section indicated by a broken line of the stator blade 123 shown in FIG. 30 .
- a stator blade 123 of a type without an outer rim 700 (type that holds and fixes the blades 550 only by the inner rim 600) may also be used.
- FIG. 32 is a diagram showing a stator blade 123 cut in half
- FIG. 33 is a partially enlarged view of a circle section indicated by a broken line in FIG. 32 .
- a rotor blade in one stage of rotor blades in multiple stages has an outer diameter that is smaller at an outlet port side than at an inlet port side, or a rotor blade in one stage of rotor blades in multiple stages has an inner diameter that is larger at the outlet port side than at the inlet port side.
- FIGS. 34 and 35 are diagrams for illustrating a conventional technique.
- FIG. 34 is a cross-sectional view for illustrating a configuration of a conventional turbomolecular pump including stator blades 123 each including an inner rim 600 and an outer rim 700 (of the type shown in FIG. 30 ).
- FIG. 35 is a partially enlarged view of FIG. 34 .
- a flow of exhaust gas is in a direction indicated by the arrow from the inlet port side to the outlet port side.
- the inner rim 600 (outer side) and the outer rim 700 (inner side) of the installed stator blades 123 are arranged horizontally with respect to the exhaust direction and thus do not particularly contribute to exhaustion operation of the turbomolecular pump.
- an upper surface of a stator blade spacer located at a position where the outer diameter of the rotor blade is reduced has a section extending perpendicular to the exhaust direction. This configuration reflects gas molecules transferred from the upstream s ide rotor blade directly toward the inlet port, whereby exhaustion performance is lowered.
- outer and inner rims of stator blades are arranged horizontally with respect to the gas exhaust direction and therefore do not contribute to exhaustion efficiency.
- the present invention according to claim 1 provides a vacuum pump including: a casing that has an inlet port and an outlet port; a rotating shaft that is rotationally supported inside the casing; rotor blades in multiple stages that are fixed to the rotating shaft and rotatable together with the rotating shaft; and stator blades in multiple stages that are fixed to the casing and located between the rotor blades, the rotor blade in at least one stage of the rotor blades in multiple stages being configured to have an outer diameter that is smaller at an outlet port side than at an inlet port side, or the rotor blade in at least one stage of the rotor blades in multiple stages being configured to have an inner diameter that is larger at the outlet port side than at the inlet port side, wherein an outer circumference portion or an inner circumference portion of the stator blade that is located immediately above the rotor blade having a smaller outer diameter or immediately above the rotor blade having an larger inner diameter has a tapered surface sloping down to the outlet port side.
- the invention according to claim 2 provides the vacuum pump according to claim 1, wherein the stator blade includes a plurality of radially arranged blades and an inner rim or an outer rim that holds the plurality of blades, and an outer circumference surface of the inner rim or an inner circumference surface of the outer rim has a tapered surface sloping down to the outlet port side.
- the invention according to claim 3 provides the vacuum pump according to claim 1, wherein the stator blade includes a plurality of radially arranged blades and a spacer portion that holds the plurality of blades and enables positioning of the stator blade in a height direction, and an inner circumference surface of the spacer portion has a tapered surface sloping down to the outlet port side.
- the invention according to claim 4 provides the vacuum pump according to claim 2 or 3, wherein the stator blade is undercut to surfaces of the plurality of blades facing the outlet port side.
- the invention according to claim 5 provides the vacuum pump according to claim 2 or 3, wherein the stator blade has a vertical surface or a tapered surface on a rear side of the plurality of blades.
- the invention according to claim 6 provides the vacuum pump according to claim 1, wherein a protrusion is provided that extends within a range of the stator blade in a height direction from a spacer portion that holds a casing side of the stator blade and enables positioning of the stator blade in the height direction, and at least a part of an inner circumference surface of the spacer portion and the protrusion has a tapered surface sloping down to the outlet port side.
- the invention according to claim 7 provides a stator blade for a vacuum pump including a casing having an inlet port and an outlet port, the spacer including: a plurality of radially arranged blades; and an inner rim or an outer rim that holds the plurality of blades, wherein an outer circumference surface of the inner rim or an inner circumference surface of the outer rim has a tapered surface sloping down to the outlet port side.
- the invention according to claim 8 provides a spacer for a vacuum pump including a casing having an inlet port and an outlet port, the spacer including: a spacer portion that is configured to, when a stator blade having a plurality of radially arranged blades is placed, hold a casing side of the stator blade and enable positioning of the stator blade in a height direction; and a protrusion that extends from the spacer portion within a range of the stator blade in the height direction, wherein at least a part of an inner circumference surface of the spacer portion and the protrusion has a tapered surface sloping down to the outlet port side.
- the exhaustion performance of a vacuum pump is enhanced by improving the shape of an inner rim, an outer rim, or a spacer of a stator blade of the vacuum pump.
- a vacuum pump in which the rotor blade in at least one stage of the rotor blades in multiple stages has an outer diameter that is smaller at a side corresponding to the outlet port, or the rotor blade in at least one stage of the rotor blades in multiple stages has an inner diameter that is larger at a side corresponding to the outlet port, at least one of an inner circumference portion or an inner circumference portion of the stator blade that is located immediately above the rotor blade having a smaller outer diameter or immediately above the rotor blade having a larger inner diameter has a tapered surface (inclined surface) sloping down toward the outlet port.
- the outer circumference portion or the inner circumference portion of a stator blade which do not function to exhaust gas in conventional techniques, also contribute to the exhaustion, thereby enhancing the exhaustion efficiency of the vacuum pump.
- FIGS. 1 to 29A and 29B preferred embodiments of the present invention are now described in detail.
- FIG. 1 is a schematic view showing an example of the configuration of a turbomolecular pump 100 according to an embodiment of the present invention.
- the turbomolecular pump 100 has a circular outer cylinder 127 having an inlet port 101 at its upper end.
- a rotating body 103 in the outer cylinder 127 includes a plurality of rotor blades 102 (102a, 102b, 102c, ...), which are turbine blades for gas suction and exhaustion, in its outer circumference section.
- the rotor blades 102 extend radially in multiple stages.
- the rotating body 103 has a rotor shaft 113 in its center.
- the rotor shaft 113 is suspended in the air and position-controlled by a magnetic bearing of 5-axis control, for example.
- Upper radial electromagnets 104 include four electromagnets arranged in pairs on an X-axis and a Y-axis.
- Four upper radial sensors 107 are provided in close proximity to the upper radial electromagnets 104 and associated with the respective upper radial electromagnets 104.
- Each upper radial sensor 107 may be an inductance sensor or an eddy current sensor having a conduction winding, for example, and detects the position of the rotor shaft 113 based on a change in the inductance of the conduction winding, which changes according to the position of the rotor shaft 113.
- the upper radial sensors 107 are configured to detect a radial displacement of the rotor shaft 113, that is, the rotating body 103 fixed to the rotor shaft 113, and send it to the controller 200.
- a compensation circuit having a PID adjustment function generates an excitation control command signal for the upper radial electromagnets 104 based on a position signal detected by the upper radial sensors 107. Based on this excitation control command signal, an amplifier circuit 150 (described below) shown in FIG. 2 controls and excites the upper radial electromagnets 104 to adjust a radial position of an upper part of the rotor shaft 113.
- the rotor shaft 113 may be made of a high magnetic permeability material (such as iron and stainless steel) and is configured to be attracted by magnetic forces of the upper radial electromagnets 104. The adjustment is performed independently in the X-axis direction and the Y-axis direction.
- Lower radial electromagnets 105 and lower radial sensors 108 are arranged in a similar manner as the upper radial electromagnets 104 and the upper radial sensors 107 to adjust the radial position of the lower part of the rotor shaft 113 in a similar manner as the radial position of the upper part.
- axial electromagnets 106A and 106B are arranged so as to vertically sandwich a metal disc 111, which has a shape of a circular disc and is provided in the lower part of the rotor shaft 113.
- the metal disc 111 is made of a high magnetic permeability material such as iron.
- An axial sensor 109 is provided to detect an axial displacement of the rotor shaft 113 and send an axial position signal to the controller 200.
- the compensation circuit having the PID adjustment function may generate an excitation control command signal for each of the axial electromagnets 106A and 106B based on the signal on the axial position detected by the axial sensor 109. Based on these excitation control command signals, the amplifier circuit 150 controls and excites the axial electromagnets 106A and 106B separately so that the axial electromagnet 106A magnetically attracts the metal disc 111 upward and the axial electromagnet 106B attracts the metal disc 111 downward. The axial position of the rotor shaft 113 is thus adjusted.
- the controller 200 appropriately adjusts the magnetic forces exerted by the axial electromagnets 106A and 106B on the metal disc 111, magnetically levitates the rotor shaft 113 in the axial direction, and suspends the rotor shaft 113 in the air in a non-contact manner.
- the amplifier circuit 150 which controls and excites the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A and 106B, is described below.
- the motor 121 includes a plurality of magnetic poles circumferentially arranged to surround the rotor shaft 113. Each magnetic pole is controlled by the controller 200 so as to drive and rotate the rotor shaft 113 via an electromagnetic force acting between the magnetic pole and the rotor shaft 113.
- the motor 121 also includes a rotational speed sensor (not shown), such as a Hall element, a resolver, or an encoder, and the rotational speed of the rotor shaft 113 is detected based on a detection signal of the rotational speed sensor.
- phase sensor (not shown) is attached adjacent to the lower radial sensors 108 to detect the phase of rotation of the rotor shaft 113.
- the controller 200 detects the position of the magnetic poles using both detection signals of the phase sensor and the rotational speed sensor.
- a plurality of stator blades 123 (123a, 123b, 123c, ...) are arranged slightly spaced apart from the rotor blades 102 (102a, 102b, 102c, ).
- Each rotor blade 102 (102a, 102b, 102c, ...) is 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 through collision.
- the stator blades 123 are also inclined by a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113.
- the stator blades 123 extend inward of the outer cylinder 127 and alternate with the stages of the rotor blades 102.
- the outer circumference ends of the stator blades 123 are inserted between and thus supported by a plurality of layered stator blade spacers 125 (125a, 125b, 125c, ).
- the stator blade spacers 125 are ring-shaped members made of a metal, such as aluminum, iron, stainless steel, or copper, or an alloy containing these metals as components, for example.
- the outer cylinder 127 is fixed to the outer circumferences of the stator blade spacers 125 with a slight gap.
- a base portion 129 is located at the base of the outer cylinder 127.
- the base portion 129 has an outlet port 133 providing communication to the outside. The exhaust gas transferred to the base portion 129 through the inlet port 101 from the chamber is then sent to the outlet port 133.
- a threaded spacer 131 may be provided between the lower part of the stator blade spacer 125 and the base portion 129.
- the threaded spacer 131 is a cylindrical member made of a metal such as aluminum, copper, stainless steel, or iron, or an alloy containing these metals as components.
- the threaded spacer 131 has a plurality of helical thread grooves 131a in its inner circumference surface. When exhaust gas molecules move in the rotation direction of the rotating body 103, these molecules are transferred toward the outlet port 133 in the direction of the helix of the thread grooves 131a.
- a cylindrical portion 102d extends downward.
- the outer circumference surface of the cylindrical portion 102d is cylindrical and projects toward the inner circumference surface of the threaded spacer 131.
- the outer circumference surface is adjacent to but separated from the inner circumference surface of the threaded spacer 131 by a predetermined gap.
- the exhaust gas transferred to the thread grooves 131a by the rotor blades 102 and the stator blades 123 is guided by the thread grooves 131a to the base portion 129.
- the base portion 129 is a disc-shaped member forming the base section of the turbomolecular pump 100, and is generally made of a metal such as iron, aluminum, or stainless steel.
- the base portion 129 physically holds the turbomolecular pump 100 and also serves as a heat conduction path.
- the base portion 129 is preferably made of rigid metal with high thermal conductivity, such as iron, aluminum, or copper.
- stator blade spacers 125 are joined to each other at the outer circumference portion and conduct the heat received by the stator blades 123 from the rotor blades 102, the friction heat generated when the exhaust gas comes into contact with the stator blades 123, and the like to the outside.
- the threaded spacer 131 is provided at the outer circumference of the cylindrical portion 102d of the rotating body 103, and the thread grooves 131a are engraved in the inner circumference surface of the threaded spacer 131.
- this may be inversed in some cases, and a thread groove may be engraved in the outer circumference surface of the cylindrical portion 102d, while a spacer having a cylindrical inner circumference surface may be arranged around the outer circumference surface.
- the electrical portion may be surrounded by a stator column 122.
- the inside of the stator column 122 may be maintained at a predetermined pressure by purge gas.
- the base portion 129 has a pipe (not shown) through which the purge gas is introduced.
- the introduced purge gas is sent to the outlet port 133 through gaps between a 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 circumference cylindrical portion of the rotor blade 102.
- the turbomolecular pump 100 requires the identification of the model and control based on individually adjusted unique parameters (for example, various characteristics associated with the model). To store these control parameters, the turbomolecular pump 100 includes an electronic circuit portion 141 in its main body.
- the electronic circuit portion 141 may include a semiconductor memory, such as an EEPROM, electronic components such as semiconductor elements for accessing the semiconductor memory, and a substrate 143 for mounting these components.
- the electronic circuit portion 141 is housed under a rotational speed sensor (not shown) near the center, for example, of the base portion 129, which forms the lower part of the turbomolecular pump 100A, and is closed by an airtight bottom lid 145.
- Some process gas introduced into the chamber in the manufacturing process of semiconductors has the property of becoming solid when its pressure becomes higher than a predetermined value or its temperature becomes lower than a predetermined value.
- the pressure of the exhaust gas is lowest at the inlet port 101 and highest at the outlet port 133.
- the pressure of the process gas increases beyond a predetermined value or its temperature decreases below a predetermined value while the process gas is being transferred from the inlet port 101 to the outlet port 133, the process gas is solidified and adheres and accumulates on the inner side of the turbomolecular pump 100.
- a solid product for example, AlCl 3
- a low vacuum 760 [torr] to 10 -2 [torr]
- a low temperature about 20 [°C]
- the deposit of the process gas accumulates in the turbomolecular pump 100
- the accumulation may narrow the pump flow passage and degrade the performance of the turbomolecular pump 100.
- the above-mentioned product tends to solidify and adhere in areas with higher pressures, such as the vicinity of the outlet port and the vicinity of the threaded spacer 131.
- a heater or annular water-cooled tube 149 (not shown) is wound around the outer circumference of the base portion 129, and a temperature sensor (e.g., a thermistor, not shown) is embedded in the base portion 129, for example.
- the signal of this temperature sensor is used to perform control to maintain the temperature of the base portion 129 at a constant high temperature (preset temperature) by heating with the heater or cooling with the water-cooled tube 149 (hereinafter referred to as TMS (temperature management system)).
- FIG. 2 is a circuit diagram of the amplifier circuit 150.
- an electromagnet winding 151 forming an upper radial electromagnet 104 or the like is connected to a positive electrode 171a of a power supply 171 via a transistor 161, and the other end is connected to a negative electrode 171b of the power supply 171 via a current detection circuit 181 and a transistor 162.
- Each transistor 161, 162 is a power MOSFET and has a structure in which a diode is connected between the source and the drain thereof.
- a cathode terminal 161a of its diode is connected to the positive electrode 171a, and an anode terminal 161b is connected to one end of the electromagnet winding 151.
- a cathode terminal 162a of its diode is connected to a current detection circuit 181, and an anode terminal 162b is connected to the negative electrode 171b.
- a diode 165 for current regeneration has a cathode terminal 165a connected to one end of the electromagnet winding 151 and an anode terminal 165b connected to the negative electrode 171b.
- a diode 166 for current regeneration has a cathode terminal 166a connected to the positive electrode 171a and an anode terminal 166b connected to the other end of the electromagnet winding 151 via the current detection circuit 181.
- the current detection circuit 181 may include a Hall current sensor or an electric resistance element, for example.
- the amplifier circuit 150 configured as described above corresponds to one electromagnet. Accordingly, when the magnetic bearing uses 5-axis control and has ten electromagnets 104, 105, 106A, and 106B in total, an identical amplifier circuit 150 is configured for each of the electromagnets. These ten amplifier circuits 150 are connected to the power supply 171 in parallel.
- An amplifier control circuit 191 may be formed by a digital signal processor portion (not shown, hereinafter referred to as a DSP portion) of the controller 200.
- the amplifier control circuit 191 switches the transistors 161 and 162 between on and off.
- the amplifier control circuit 191 is configured to compare a 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. The result of this comparison is used to determine the magnitude of the pulse width (pulse width time Tp1, Tp2) generated in a control cycle Ts, which is one cycle in PWM control. As a result, gate drive signals 191a and 191b having this pulse width are output from the amplifier control circuit 191 to gate terminals of the transistors 161 and 162.
- the rotating body 103 may require positional control at high speed and with a strong force.
- a high voltage of about 50 V is used for the power supply 171 to enable a rapid increase (or decrease) in the current flowing through the electromagnet winding 151.
- a capacitor is generally connected between the positive electrode 171a and the negative electrode 171b of the power supply 171 to stabilize the power supply 171 (not shown).
- the transistors 161 and 162 when one of the transistors 161 and 162 is turned on and the other is turned off, a freewheeling current is maintained. Passing the freewheeling current through the amplifier circuit 150 in this manner reduces the hysteresis loss in the amplifier circuit 150, thereby limiting the power consumption of the entire circuit to a low level. Moreover, by controlling the transistors 161 and 162 as described above, high frequency noise, such as harmonics, generated in the turbomolecular pump 100 can be reduced. Furthermore, by measuring this freewheeling current with the current detection circuit 181, the electromagnet current iL flowing through the electromagnet winding 151 can be detected.
- the transistors 161 and 162 are simultaneously on only once in the control cycle Ts (for example, 100 ⁇ s) for the time corresponding to the pulse width time Tp1. During this time, the electromagnet current iL increases accordingly toward the current value iLmax (not shown) that can be passed from the positive electrode 171a to the negative electrode 171b via the transistors 161 and 162.
- the transistors 161 and 162 are simultaneously off only once in the control cycle Ts for the time corresponding to the pulse width time Tp2. During this time, the electromagnet current iL decreases accordingly toward the current value iLmin (not shown) that can be regenerated from the negative electrode 171b to the positive electrode 171a via the diodes 165 and 166.
- FIG. 5 is a schematic view showing an example of the configuration of the turbomolecular pump according to the first embodiment.
- FIG. 6 is a partially enlarged view of the turbomolecular pump according to the first embodiment shown in FIG. 5 .
- one or both of an inner rim 600 or an outer rim 700 of a stator blade 123 have tapered surfaces (inner rim tapered surface 610, outer rim tapered surface 710) that slope down toward the outlet port.
- the tapered surface is provided in a section in which the rotor blade in one stage of the rotor blades in multiple stages has an outer diameter that is smaller at the side corresponding to the outlet port, or a section in which the rotor blade in one stage of the rotor blades in multiple stages has an inner diameter that is larger at the side corresponding to the outlet port.
- a stator blade 123 having a tapered surface is arranged between these rotor blades.
- FIG. 7 is a diagram showing a stator blade 123 according to the first embodiment A in which the inner rim has a tapered surface.
- the inner rim 600 has an inner rim tapered surface 610 sloping down toward the outlet port.
- the molecules are transferred to and collide with the inner rim tapered surface 610, the molecules are reflected at a right angle, hit by the rotor blade in the upper stage, and sent to the next stage.
- the inner rim 600 having the inner rim tapered surface 610 contributes to the exhaustion action.
- the inner rim 600 and the outer rim 700 hold and fix the blades 550 of the stator blade 123.
- FIG. 8 is a diagram showing a stator blade 123 according to the first embodiment B in which the inner rim has a tapered surface.
- the stator blade 123 according to the first embodiment B has inner rim vertical surfaces 620 and inner rim circumference surfaces 630.
- stator blade 123 is made of aluminum and manufactured as a casting using a mold or by cutting.
- the inner rim vertical surfaces 620 are provided for this reason.
- the section under each blade 550 in which an inner rim vertical surface 620 is formed has an inner rim circumference surface 630, which is parallel to the outer rim 700.
- FIG. 9 is a diagram showing a stator blade 123 according to the first embodiment C in which the inner rim and the outer rim have tapered surfaces. As shown in this figure, not only the inner rim 600 but also the outer rim 700 has an outer rim tapered surface 710 sloping down toward the outlet port.
- the outer rim 700 in addition to the inner rim 600, the outer rim 700 also contributes to the exhaustion action.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the outer rim tapered surface 710.
- FIG. 10 is a diagram showing a stator blade 123 according to the first embodiment D in which the inner rim and the outer rim have tapered surfaces, vertical surfaces, and circumference surfaces.
- outer rim vertical surfaces 720 are provided because the product needs to be removed from a mold when it is manufactured as a casting using the mold.
- the section under each blade 550 in which an outer rim vertical surface 720 is formed has an outer rim circumference surface 730, which is parallel to the inner rim 600.
- FIGS. 11A and 11B are diagrams showing a stator blade 123 according to the first embodiment E in which the inner rim and the outer rim have tapered surfaces and the outer rim has a tapered surface above (below) the blades.
- the inner rim 600 has the same shape as the first embodiment A and the first embodiment C, but the configuration of the outer rim 700 differs from that of the first embodiment C. That is, in the embodiment shown in FIG. 11A , the outer rim tapered surface 710 extends above the surfaces of the blades 550, forming an extra portion 740.
- the outer rim tapered surface 710 extends to the lower side beyond the back surfaces of the blades 550, forming an extra portion 740.
- This extra portion 740 facilitates the setting of the axial dimension of the stator blade 123. That is, the adjustment in the height direction can be made within a range that does not affect the blades 550.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the outer rim tapered surface 710.
- the first embodiment E does not have a vertical surface and is therefore manufactured by cutting.
- FIG. 12 is a diagram showing a stator blade 123 according to the first embodiment F in which the inner rim and the outer rim have tapered surfaces and an inner circumference surface is provided above (below) the blades.
- the inner rim 600 has the same shape as the first embodiment A and the first embodiment C, but the configuration of the outer rim 700 differs from that of the first embodiment C. That is, an outer rim inner circumference surface 760 is formed above (below) the surfaces of the blades 550. Unlike the outer rim tapered surface 710, the outer rim inner circumference surface 760 is parallel to the axis of the turbomolecular pump 100.
- the positioning in the axial direction is achieved when installing the stator blade 123 in the turbomolecular pump 100.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the tapered surface 710.
- the first embodiment F does not have a vertical surface and is therefore manufactured by cutting.
- FIG. 13 is a diagram showing a stator blade 123 according to the first embodiment G in which the inner rim and the outer rim have tapered surfaces and vertical surfaces and an inner circumference surface is provided above (below) the blades of the outer rim.
- the difference between this embodiment G and the first embodiment F is that inner rim vertical surfaces 620 and outer rim vertical surfaces 720 are provided.
- the positioning in the axial direction is achieved when installing the stator blade 123 in the turbomolecular pump 100.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the outer rim tapered surface 710.
- FIGS. 14A and 14B are diagrams showing a stator blade 123 according to the first embodiment H in which the inner rim and the outer rim have tapered surfaces and vertical surfaces and the outer rim has a tapered surface above (below) the blades.
- FIG. 14A is an external view as seen from above
- FIG. 14B is an external view as seen from below.
- the presence of the extra portion 740 facilitates the setting of the axial dimension of the stator blade 123.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the tapered surface 710.
- FIG. 15 is a diagram showing a stator blade 123 according to the first embodiment I in which the inner rim and the outer rim have tapered surfaces and a flange is provided.
- This embodiment I has a flange 750 projecting outward (toward the outer cylinder 127 when installed) from the outer rim 700.
- This flange 750 allows the stator blade 123 to be positioned and held in the axial direction. That is, by adjusting the thickness (height in the axial direction) of the flange 750, the positioning in the axial direction of the stator blade 123 is achieved. Also, this flange 750 is held so the stator blade 123 is fixed to the outer cylinder 127.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the outer rim tapered surface 710.
- the first embodiment I does not have a vertical surface and is therefore manufactured by cutting.
- FIG. 16 is a diagram showing a stator blade 123 according to the first embodiment J in which the inner rim and the outer rim have tapered surfaces and inner rim vertical surfaces, outer rim vertical surfaces and a flange is provided.
- this embodiment J has a flange 750 projecting outward (toward the outer cylinder 127 when installed) from the outer rim 700.
- This flange 750 allows the stator blade 123 to be positioned and held in the axial direction. That is, by adjusting the thickness (height in the axial direction) of the flange 750, the positioning in the axial direction of the stator blade 123 is achieved. Also, this flange 750 is held so the stator blade 123 is fixed to the outer cylinder 127.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the outer rim tapered surface 710.
- FIGS. 17 to 21 A second embodiment is now described with reference to FIGS. 17 to 21 .
- FIG. 17 is a partially enlarged view of a turbomolecular pump according to the second embodiment.
- the outer rim 700 of a stator blade 123 has an outer rim tapered surface 710, which slopes down toward the outlet port, and an outer rim inner circumference surface 760. That is, the outer rim 700 has both the outer rim tapered surface 710 and the outer rim inner circumference surface 760.
- the inner rim 600 is the same as that in the first embodiment.
- FIG. 18 is a diagram showing a stator blade 123 according to the second embodiment A in which the outer rim has a tapered surface and an inner circumference surface.
- the outer rim tapered surface 710 is located at a position corresponding to the blades 550.
- the outer rim inner circumference surface 760 is provided below the outer rim tapered surface 710. This outer rim inner circumference surface 760 is not inclined and is parallel to the axis of the turbomolecular pump 100.
- the positioning of the stator blade 123 is achieved by adjusting the outer rim inner circumference surface 760 in the height direction.
- the absence of a blade 550 in the position corresponding to the outer rim inner circumference surface 760 facilitates the adjustment.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the outer rim tapered surface 710.
- the second embodiment A does not have a vertical surface and is therefore manufactured by cutting.
- FIG. 19 is a diagram showing a stator blade 123 according to the second embodiment B in which the outer rim has a tapered surface, an inner circumference surface, and a flange.
- the outer rim tapered surface 710 is located at a position corresponding to the blades 550.
- the outer rim inner circumference surface 760 is provided below the outer rim tapered surface 710.
- the difference between the second embodiment B and the second embodiment A is that the outer rim 700 has a flange 750 projecting outward (toward the outer cylinder 127 when installed).
- This flange 750 allows the stator blade 123 to be positioned and held in the axial direction. That is, by adjusting the thickness (height in the axial direction) of the flange 750, the positioning in the axial direction of the stator blade 123 is achieved. Also, this flange 750 is held so the stator blade 123 is fixed to the outer cylinder 127.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the outer rim tapered surface 710.
- the second embodiment B does not have a vertical surface and is therefore manufactured by cutting.
- FIG. 20 is a diagram showing a stator blade 123 according to the second embodiment C in which the outer rim has a tapered surface and an inner circumference surface and inner rim vertical surfaces and outer rim vertical surface are provided.
- the outer rim tapered surface 710 is located at a position corresponding to the blades 550.
- the outer rim inner circumference surface 760 is provided below the outer rim tapered surface 710.
- the difference between this second embodiment C and the second embodiment A is that the inner rim vertical surface 630 and the outer rim vertical surface 720 are provided because the product needs to be removed from a mold when it is manufactured as a casting using the mold.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the outer rim tapered surface 710.
- FIG. 21 is a diagram showing a stator blade 123 according to the second embodiment D in which the outer rim has a tapered surface, an inner circumference surface, and a flange.
- the outer rim tapered surface 710 is located at a position corresponding to the blades 550.
- the outer rim inner circumference surface 760 is provided below the outer rim tapered surface 710.
- the difference between the second embodiment D and the second embodiment C is that the outer rim 700 has a flange 750 projecting outward (toward the outer cylinder 127 when installed).
- This flange 750 allows the stator blade 123 to be positioned and held in the axial direction. That is, by adjusting the thickness (height in the axial direction) of the flange 750, the positioning in the axial direction of the stator blade 123 is achieved. Also, this flange 750 is held so the stator blade 123 is fixed to the outer cylinder 127.
- the inner rim 600 and the outer rim 700 each have a tapered surface (610, 710), but only the outer rim 700 may have the outer rim tapered surface 710.
- FIG. 22 is a partially enlarged view of a turbomolecular pump according to the third embodiment.
- stator blades 123 used in the first embodiment are arranged reversely or in the same orientation. At least the stator blade 123 in the last stage is reversely arranged.
- stator blades 123 By arranging the stator blades 123 in this manner, the products of the same size (the stator blades 123) may be used for different functions, reducing the manufacturing costs.
- a fourth embodiment is now described with reference to FIGS. 23 to 25 .
- FIG. 23 is a partially enlarged view of a turbomolecular pump according to the fourth embodiment.
- the inner rim 600 of a stator blade 123 has an inner rim tapered surface 610 sloping down toward the outlet port. That is, the inner rim 600 that is located in a section in which the diameter at the bases of the blades 550 of the stator blade 123 on the upstream side is smaller than the diameter at the bases of the blades 550 of the stator blade 123 on the downstream side has an inner rim tapered surface 610.
- FIG. 24 is a diagram showing a stator blade 123 according to the fourth embodiment A in which the inner rim 600 has an inner rim tapered surface 610.
- the inner rim 600 shown in FIG. 24 is manufactured by cutting because it does not have inner rim vertical surfaces 620.
- FIG. 25 is a diagram showing a stator blade 123 according to the fourth embodiment B in which the inner rim 600 has an inner rim tapered surface 610 and inner rim vertical surfaces.
- the inner rim 600 shown in FIG. 25 is manufactured by casting using a mold because it has the inner rim vertical surfaces 620.
- FIGS. 24 and 25 both show a type of stator blade 123 without an outer rim 700, but the fourth embodiment can also be applied to a type of stator blade 123 with an outer rim 700.
- a fifth embodiment is now described with reference to FIGS. 26 to 28 .
- FIG. 26 is a partially enlarged view of a turbomolecular pump according to the fifth embodiment.
- This fifth embodiment relates to a stator blade spacer 800 having a stator blade spacer portion 870 that holds the side of a stator blade 123 corresponding to the outer frame 127 and enables the positioning of the stator blades 123 in the height direction.
- FIG. 27 (the fifth embodiment A) and FIG. 28 (the fifth embodiment B) are diagrams each showing the appearance of a stator blade spacer 800.
- the stator blade spacer 800 has protrusions 860 extending in the height direction from the spacer portion 870 within the range of the stator blade 123 in the height direction.
- At least a part of the inner circumference surface 830 of the stator blade spacer portion 870 and the protrusions 860 has a stator blade spacer tapered surface 810 sloping down toward the outlet port.
- the inner circumference surface 830 of the stator blade spacer portion 870 and the range in which the protrusions 860 extend within the range of the stator blade 123 in the height direction are also defined as the "outer circumference portion of the stator blade".
- Blade fitting grooves 820 to which the blades 550 of a stator blade 123 is fitted and held when installed, are provided between the protrusions 860.
- the stator blade spacer 800 shown in FIG. 28 further has a stator blade spacer flange 850.
- the stator blade spacer flange 850 enables the positioning of the stator blade spacer 800 in the height direction. Moreover, the stator blade spacer 800 can be held and fixed by holding the stator blade spacer flange 850.
- FIG. 29A is a cross-sectional view of a stator blade 123 corresponding to the first embodiment H.
- the tapered surface of the stator blade 123 is at the angle of the line (imaginary line) connecting the inner circumference lower end A of a stator blade spacer 125 to the inner circumference upper end B of a stator blade spacer 125.
- FIG. 29B is a cross-sectional view of a stator blade 123 corresponding to the second embodiment D.
- the tapered surface of the stator blade 123 is at the angle of the line (imaginary line) connecting the point of intersection H of a perpendicular drawn from the distal end X of the upper rotor blade 102 to the lower stator blade 123 to the point at (1) the basal end of a blade 550 of the stator blade 123 or (2) the inner circumference lower side of the stator blade 123.
- the tapered surface may have various angles, and the angle may be appropriately determined according to various conditions.
- a gently curved surface may also be used.
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Abstract
A vacuum pump with enhanced exhaustion performance achieved by innovating stator blades (inner and outer rims) and spacers installed in the vacuum pump is provided. In the vacuum pump in which the rotor blade in one stage has an outer diameter that is smaller at an outlet port side, or the rotor blade in one stage has an inner diameter that is larger at an outlet port side, at least one of an outer circumference portion or an inner circumference portion of the stator blade that is located immediately above the rotor blade having a smaller outer diameter or immediately above the rotor blade having a larger inner diameter has a tapered surface sloping down to an outlet port side. By providing the tapered surface, entering molecules are reflected at a right angle, sent toward an inner circumference side, and hit by the rotor blade in the upper stage. The molecules are thus sent to a next exhaustion stage.
Description
- The present invention relates to a vacuum pump, a stator blade, and a spacer, and more particularly to a structure for improving exhaustion efficiency of a vacuum pump.
- Conventionally, a vacuum pumps is widely used such as a turbomolecular pump that exhausts gas by rotating at high speed a rotor potion (a shaft and a rotor) and a rotating portion, which includes rotor blades and a rotating cylinder, in a casing having an inlet port and an outlet port.
- Such a vacuum pump exhausts gas through interaction between rotor blades in multiple stages rotating at high speed and stator blades in multiple stages fixed to the casing.
- As shown in
FIG. 30 , astator blade 123 used in this vacuum pump includes a plurality ofblades 550, aninner rim 600, which holds and fixes inner sides (sides corresponding to the rotor portion when installed) of the plurality ofblades 550, and anouter rim 700, which holds and fixes outer sides (sides corresponding to the casing when installed) of theblades 550.FIG. 31 is a partially enlarged view of a circle section indicated by a broken line of thestator blade 123 shown inFIG. 30 . - As shown in
FIG. 32 , astator blade 123 of a type without an outer rim 700 (type that holds and fixes theblades 550 only by the inner rim 600) may also be used. -
FIG. 32 is a diagram showing astator blade 123 cut in half, andFIG. 33 is a partially enlarged view of a circle section indicated by a broken line inFIG. 32 . - In this vacuum pump, due to design requirements, a rotor blade in one stage of rotor blades in multiple stages has an outer diameter that is smaller at an outlet port side than at an inlet port side, or a rotor blade in one stage of rotor blades in multiple stages has an inner diameter that is larger at the outlet port side than at the inlet port side.
-
FIGS. 34 and35 are diagrams for illustrating a conventional technique. -
FIG. 34 is a cross-sectional view for illustrating a configuration of a conventional turbomolecular pump includingstator blades 123 each including aninner rim 600 and an outer rim 700 (of the type shown inFIG. 30 ). -
FIG. 35 is a partially enlarged view ofFIG. 34 . - As shown in
FIG. 35 , a flow of exhaust gas is in a direction indicated by the arrow from the inlet port side to the outlet port side. - As shown in
FIG. 35 , the inner rim 600 (outer side) and the outer rim 700 (inner side) of the installedstator blades 123 are arranged horizontally with respect to the exhaust direction and thus do not particularly contribute to exhaustion operation of the turbomolecular pump. - Also, an upper surface of a stator blade spacer located at a position where the outer diameter of the rotor blade is reduced has a section extending perpendicular to the exhaust direction. This configuration reflects gas molecules transferred from the upstream s
ide rotor blade directly toward the inlet port, whereby exhaustion performance is lowered. -
- Patent Document 1:
Japanese Patent Application Publication No. 2007-2692 - Patent Document 2:
Japanese Patent Application Publication No. 2018-35718 - In a vacuum pumps disclosed in Patent Document 1 and Patent Document 2, outer and inner rims of stator blades are arranged horizontally with respect to the gas exhaust direction and therefore do not contribute to exhaustion efficiency.
- In recent years, there has been a need for further improving exhaustion efficiency of a vacuum pump without increasing the size of a pump or increasing a rotation speed of a rotor portion.
- In view of the above, it is an object of the present invention to provide a vacuum pump with enhanced exhaustion performance achieved by innovating stator blades (inner and outer rims) and spacers installed in the vacuum pump.
- The present invention according to claim 1 provides a vacuum pump including: a casing that has an inlet port and an outlet port; a rotating shaft that is rotationally supported inside the casing; rotor blades in multiple stages that are fixed to the rotating shaft and rotatable together with the rotating shaft; and stator blades in multiple stages that are fixed to the casing and located between the rotor blades, the rotor blade in at least one stage of the rotor blades in multiple stages being configured to have an outer diameter that is smaller at an outlet port side than at an inlet port side, or the rotor blade in at least one stage of the rotor blades in multiple stages being configured to have an inner diameter that is larger at the outlet port side than at the inlet port side, wherein an outer circumference portion or an inner circumference portion of the stator blade that is located immediately above the rotor blade having a smaller outer diameter or immediately above the rotor blade having an larger inner diameter has a tapered surface sloping down to the outlet port side.
- The invention according to claim 2 provides the vacuum pump according to claim 1, wherein the stator blade includes a plurality of radially arranged blades and an inner rim or an outer rim that holds the plurality of blades, and an outer circumference surface of the inner rim or an inner circumference surface of the outer rim has a tapered surface sloping down to the outlet port side.
- The invention according to claim 3 provides the vacuum pump according to claim 1, wherein the stator blade includes a plurality of radially arranged blades and a spacer portion that holds the plurality of blades and enables positioning of the stator blade in a height direction, and an inner circumference surface of the spacer portion has a tapered surface sloping down to the outlet port side.
- The invention according to claim 4 provides the vacuum pump according to claim 2 or 3, wherein the stator blade is undercut to surfaces of the plurality of blades facing the outlet port side.
- The invention according to claim 5 provides the vacuum pump according to claim 2 or 3, wherein the stator blade has a vertical surface or a tapered surface on a rear side of the plurality of blades.
- The invention according to claim 6 provides the vacuum pump according to claim 1, wherein a protrusion is provided that extends within a range of the stator blade in a height direction from a spacer portion that holds a casing side of the stator blade and enables positioning of the stator blade in the height direction, and at least a part of an inner circumference surface of the spacer portion and the protrusion has a tapered surface sloping down to the outlet port side.
- The invention according to claim 7 provides a stator blade for a vacuum pump including a casing having an inlet port and an outlet port, the spacer including: a plurality of radially arranged blades; and an inner rim or an outer rim that holds the plurality of blades, wherein an outer circumference surface of the inner rim or an inner circumference surface of the outer rim has a tapered surface sloping down to the outlet port side.
- The invention according to claim 8 provides a spacer for a vacuum pump including a casing having an inlet port and an outlet port, the spacer including: a spacer portion that is configured to, when a stator blade having a plurality of radially arranged blades is placed, hold a casing side of the stator blade and enable positioning of the stator blade in a height direction; and a protrusion that extends from the spacer portion within a range of the stator blade in the height direction, wherein at least a part of an inner circumference surface of the spacer portion and the protrusion has a tapered surface sloping down to the outlet port side.
- According to the present invention, the exhaustion performance of a vacuum pump is enhanced by improving the shape of an inner rim, an outer rim, or a spacer of a stator blade of the vacuum pump.
-
FIG. 1 is a schematic view showing an example of the configuration of a turbomolecular pump of an embodiment according to the present invention; -
FIG. 2 is a circuit diagram of an amplifier circuit used in an embodiment of the present invention; -
FIG. 3 is a time chart showing control performed when a current command value is greater than a detected value in an embodiment of the present invention; -
FIG. 4 is a time chart showing control performed when a current command value is less than a detected value in an embodiment of the present invention; -
FIG. 5 is a schematic view showing an example of the configuration of a turbomolecular pump according to a first embodiment of the present invention; -
FIG. 6 is a partially enlarged view of the turbomolecular pump according to the first embodiment shown inFIG. 5 ; -
FIG. 7 is a diagram showing a stator blade according to the first embodiment A in which the inner rim has a tapered surface; -
FIG. 8 is a diagram showing a stator blade according to the first embodiment B in which the inner rim has a tapered surface, vertical surfaces, and circumference surfaces; -
FIG. 9 is a diagram showing a stator blade according to the first embodiment C in which the inner rim and the outer rim have tapered surfaces; -
FIG. 10 is a diagram showing a stator blade according to the first embodiment D in which the inner rim and the outer rim have tapered surfaces, vertical surfaces, and circumference surfaces; -
FIGS. 11A and 11B are diagrams showing a stator blade according to the first embodiment E in which the inner rim and the outer rim have tapered surfaces and the outer rim has a tapered surface above (below) the blades; -
FIG. 12 is a diagram showing a stator blade according to the first embodiment F in which the inner rim and the outer rim have tapered surfaces and an inner circumference surface is provided above (below) the blades; -
FIG. 13 is a diagram showing a stator blade according to the first embodiment G in which the inner rim and the outer rim have tapered surfaces and vertical surfaces, and an inner circumference surface is provided above (below) the blades of the outer rim; -
FIGS. 14A and 14B are diagrams showing a stator blade according to the first embodiment H in which the inner rim and the outer rim have tapered surfaces and vertical surfaces and a tapered surface is provided above (below) the blades of the outer rim; -
FIG. 15 is a diagram showing a stator blade according to the first embodiment I in which the inner rim and the outer rim have tapered surfaces and a flange is provided; -
FIG. 16 is a diagram showing a stator blade according to the first embodiment J in which the inner rim and the outer rim have tapered surfaces and vertical surfaces and a flange is provided; -
FIG. 17 is a partially enlarged view showing an example of a schematic configuration of a turbomolecular pump according to a second embodiment of the invention; -
FIG. 18 is a diagram showing a stator blade according to the second embodiment A in which the outer rim has a tapered surface and an inner circumference surface; -
FIG. 19 is a diagram showing a stator blade according to the second embodiment B in which the outer rim has a tapered surface, an inner circumference surface, and a flange; -
FIG. 20 is a diagram showing a stator blade according to the second embodiment C in which the outer rim has a tapered surface and an inner circumference surface and inner rim vertical surfaces and outer rim vertical surfaces are provided; -
FIG. 21 is a diagram showing a stator blade according to the second embodiment D in which the outer rim has a tapered surface, an inner circumference surface, and a flange; -
FIG. 22 is a partially enlarged view of a turbomolecular pump according to a third embodiment; -
FIG. 23 is a partially enlarged view of a turbomolecular pump according to a fourth embodiment; -
FIG. 24 is a diagram showing a stator blade according to the fourth embodiment A in which the inner rim has an inner rim tapered surface; -
FIG. 25 is a diagram showing a stator blade according to the fourth embodiment B in which the inner rim has an inner rim tapered surface and inner rim vertical surfaces; -
FIG. 26 is a partially enlarged view of a turbomolecular pump according to a fifth embodiment; -
FIG. 27 is a diagram showing the appearance of a stator blade spacer according to the fifth embodiment A; -
FIG. 28 is a diagram showing the appearance of a stator blade spacer according to the fifth embodiment B; -
FIGS. 29A and 29B are diagrams for illustrating taper angles; -
FIG. 30 is a diagram showing a conventional stator blade; -
FIG. 31 is a partially enlarged view of the stator blade shown inFIG. 30 ; -
FIG. 32 is a diagram showing a conventional stator blade without an outer rim; -
FIG. 33 is a partially enlarged view of the stator blade shown inFIG. 32 ; -
FIG. 34 is a schematic view showing an example of the configuration of a conventional turbomolecular pump; and -
FIG. 35 is a partially enlarged view of the turbomolecular pump shown inFIG. 34 . - In present embodiments, in a vacuum pump in which the rotor blade in at least one stage of the rotor blades in multiple stages has an outer diameter that is smaller at a side corresponding to the outlet port, or the rotor blade in at least one stage of the rotor blades in multiple stages has an inner diameter that is larger at a side corresponding to the outlet port, at least one of an inner circumference portion or an inner circumference portion of the stator blade that is located immediately above the rotor blade having a smaller outer diameter or immediately above the rotor blade having a larger inner diameter has a tapered surface (inclined surface) sloping down toward the outlet port.
- By providing the tapered surface, entering molecules are reflected at a right angle, sent toward the inner circumference side, and hit by the rotor blade in the upper stage. The molecules are thus sent to the next exhaustion stage.
- In this manner, the outer circumference portion or the inner circumference portion of a stator blade, which do not function to exhaust gas in conventional techniques, also contribute to the exhaustion, thereby enhancing the exhaustion efficiency of the vacuum pump.
- Referring to
FIGS. 1 to 29A and29B , preferred embodiments of the present invention are now described in detail. -
FIG. 1 is a schematic view showing an example of the configuration of aturbomolecular pump 100 according to an embodiment of the present invention. Theturbomolecular pump 100 has a circularouter cylinder 127 having aninlet port 101 at its upper end. Arotating body 103 in theouter cylinder 127 includes a plurality of rotor blades 102 (102a, 102b, 102c, ...), which are turbine blades for gas suction and exhaustion, in its outer circumference section. Therotor blades 102 extend radially in multiple stages. Therotating body 103 has arotor shaft 113 in its center. Therotor shaft 113 is suspended in the air and position-controlled by a magnetic bearing of 5-axis control, for example. - Upper
radial electromagnets 104 include four electromagnets arranged in pairs on an X-axis and a Y-axis. Four upperradial sensors 107 are provided in close proximity to the upperradial electromagnets 104 and associated with the respective upperradial electromagnets 104. Each upperradial sensor 107 may be an inductance sensor or an eddy current sensor having a conduction winding, for example, and detects the position of therotor shaft 113 based on a change in the inductance of the conduction winding, which changes according to the position of therotor shaft 113. The upperradial sensors 107 are configured to detect a radial displacement of therotor shaft 113, that is, therotating body 103 fixed to therotor shaft 113, and send it to thecontroller 200. - In the
controller 200, for example, a compensation circuit having a PID adjustment function generates an excitation control command signal for the upperradial electromagnets 104 based on a position signal detected by the upperradial sensors 107. Based on this excitation control command signal, an amplifier circuit 150 (described below) shown inFIG. 2 controls and excites the upperradial electromagnets 104 to adjust a radial position of an upper part of therotor shaft 113. - The
rotor shaft 113 may be made of a high magnetic permeability material (such as iron and stainless steel) and is configured to be attracted by magnetic forces of the upperradial electromagnets 104. The adjustment is performed independently in the X-axis direction and the Y-axis direction. Lowerradial electromagnets 105 and lowerradial sensors 108 are arranged in a similar manner as the upperradial electromagnets 104 and the upperradial sensors 107 to adjust the radial position of the lower part of therotor shaft 113 in a similar manner as the radial position of the upper part. - Additionally,
axial electromagnets metal disc 111, which has a shape of a circular disc and is provided in the lower part of therotor shaft 113. Themetal disc 111 is made of a high magnetic permeability material such as iron. Anaxial sensor 109 is provided to detect an axial displacement of therotor shaft 113 and send an axial position signal to thecontroller 200. - In the
controller 200, the compensation circuit having the PID adjustment function may generate an excitation control command signal for each of theaxial electromagnets axial sensor 109. Based on these excitation control command signals, theamplifier circuit 150 controls and excites theaxial electromagnets axial electromagnet 106A magnetically attracts themetal disc 111 upward and theaxial electromagnet 106B attracts themetal disc 111 downward. The axial position of therotor shaft 113 is thus adjusted. - As described above, the
controller 200 appropriately adjusts the magnetic forces exerted by theaxial electromagnets metal disc 111, magnetically levitates therotor shaft 113 in the axial direction, and suspends therotor shaft 113 in the air in a non-contact manner. Theamplifier circuit 150, which controls and excites the upperradial electromagnets 104, the lowerradial electromagnets 105, and theaxial electromagnets - The
motor 121 includes a plurality of magnetic poles circumferentially arranged to surround therotor shaft 113. Each magnetic pole is controlled by thecontroller 200 so as to drive and rotate therotor shaft 113 via an electromagnetic force acting between the magnetic pole and therotor shaft 113. Themotor 121 also includes a rotational speed sensor (not shown), such as a Hall element, a resolver, or an encoder, and the rotational speed of therotor shaft 113 is detected based on a detection signal of the rotational speed sensor. - Furthermore, a phase sensor (not shown) is attached adjacent to the lower
radial sensors 108 to detect the phase of rotation of therotor shaft 113. Thecontroller 200 detects the position of the magnetic poles using both detection signals of the phase sensor and the rotational speed sensor. - A plurality of stator blades 123 (123a, 123b, 123c, ...) are arranged slightly spaced apart from the rotor blades 102 (102a, 102b, 102c, ...). Each rotor blade 102 (102a, 102b, 102c, ...) is 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 through collision. - The
stator blades 123 are also inclined by a predetermined angle from a plane perpendicular to the axis of therotor shaft 113. Thestator blades 123 extend inward of theouter cylinder 127 and alternate with the stages of therotor blades 102. The outer circumference ends of thestator blades 123 are inserted between and thus supported by a plurality of layered stator blade spacers 125 (125a, 125b, 125c, ...). - The
stator blade spacers 125 are ring-shaped members made of a metal, such as aluminum, iron, stainless steel, or copper, or an alloy containing these metals as components, for example. Theouter cylinder 127 is fixed to the outer circumferences of thestator blade spacers 125 with a slight gap. Abase portion 129 is located at the base of theouter cylinder 127. Thebase portion 129 has anoutlet port 133 providing communication to the outside. The exhaust gas transferred to thebase portion 129 through theinlet port 101 from the chamber is then sent to theoutlet port 133. - According to the application of the
turbomolecular pump 100, a threadedspacer 131 may be provided between the lower part of thestator blade spacer 125 and thebase portion 129. The threadedspacer 131 is a cylindrical member made of a metal such as aluminum, copper, stainless steel, or iron, or an alloy containing these metals as components. The threadedspacer 131 has a plurality ofhelical thread grooves 131a in its inner circumference surface. When exhaust gas molecules move in the rotation direction of therotating body 103, these molecules are transferred toward theoutlet port 133 in the direction of the helix of thethread grooves 131a. In the lowermost section of therotating body 103 below the rotor blades 102 (102a, 102b, 102c, ...), acylindrical portion 102d extends downward. The outer circumference surface of thecylindrical portion 102d is cylindrical and projects toward the inner circumference surface of the threadedspacer 131. The outer circumference surface is adjacent to but separated from the inner circumference surface of the threadedspacer 131 by a predetermined gap. The exhaust gas transferred to thethread grooves 131a by therotor blades 102 and thestator blades 123 is guided by thethread grooves 131a to thebase portion 129. - The
base portion 129 is a disc-shaped member forming the base section of theturbomolecular pump 100, and is generally made of a metal such as iron, aluminum, or stainless steel. Thebase portion 129 physically holds theturbomolecular pump 100 and also serves as a heat conduction path. As such, thebase portion 129 is preferably made of rigid metal with high thermal conductivity, such as iron, aluminum, or copper. - In this configuration, when the
motor 121 drives and rotates therotor blades 102 together with therotor shaft 113, the interaction between therotor blades 102 and thestator blades 123 causes the suction of exhaust gas from the chamber through theinlet port 101. The exhaust gas taken through theinlet port 101 moves between therotor blades 102 and thestator blades 123 and is transferred to thebase portion 129. At this time, factors such as the friction heat generated when the exhaust gas comes into contact with therotor blades 102 and the conduction of heat generated by themotor 121 increase the temperature of therotor blades 102. This heat is conducted to thestator blades 123 through radiation or conduction via gas molecules of the exhaust gas, for example. - The
stator blade spacers 125 are joined to each other at the outer circumference portion and conduct the heat received by thestator blades 123 from therotor blades 102, the friction heat generated when the exhaust gas comes into contact with thestator blades 123, and the like to the outside. - In the above description, the threaded
spacer 131 is provided at the outer circumference of thecylindrical portion 102d of therotating body 103, and thethread grooves 131a are engraved in the inner circumference surface of the threadedspacer 131. However, this may be inversed in some cases, and a thread groove may be engraved in the outer circumference surface of thecylindrical portion 102d, while a spacer having a cylindrical inner circumference surface may be arranged around the outer circumference surface. - According to the application of the
turbomolecular pump 100, to prevent the gas drawn through theinlet port 101 from entering an electrical portion, which includes the upperradial electromagnets 104, the upperradial sensors 107, themotor 121, the lowerradial electromagnets 105, the lowerradial sensors 108, theaxial electromagnets axial sensor 109, the electrical portion may be surrounded by astator column 122. The inside of thestator column 122 may be maintained at a predetermined pressure by purge gas. - In this case, the
base portion 129 has a pipe (not shown) through which the purge gas is introduced. The introduced purge gas is sent to theoutlet port 133 through gaps between aprotective bearing 120 and therotor shaft 113, between the rotor and the stator of themotor 121, and between thestator column 122 and the inner circumference cylindrical portion of therotor blade 102. - The
turbomolecular pump 100 requires the identification of the model and control based on individually adjusted unique parameters (for example, various characteristics associated with the model). To store these control parameters, theturbomolecular pump 100 includes anelectronic circuit portion 141 in its main body. Theelectronic circuit portion 141 may include a semiconductor memory, such as an EEPROM, electronic components such as semiconductor elements for accessing the semiconductor memory, and asubstrate 143 for mounting these components. Theelectronic circuit portion 141 is housed under a rotational speed sensor (not shown) near the center, for example, of thebase portion 129, which forms the lower part of the turbomolecular pump 100A, and is closed by anairtight bottom lid 145. - Some process gas introduced into the chamber in the manufacturing process of semiconductors has the property of becoming solid when its pressure becomes higher than a predetermined value or its temperature becomes lower than a predetermined value. In the turbomolecular pump 100A, the pressure of the exhaust gas is lowest at the
inlet port 101 and highest at theoutlet port 133. When the pressure of the process gas increases beyond a predetermined value or its temperature decreases below a predetermined value while the process gas is being transferred from theinlet port 101 to theoutlet port 133, the process gas is solidified and adheres and accumulates on the inner side of theturbomolecular pump 100. - For example, when SiCl4 is used as the process gas in an Al etching apparatus, according to the vapor pressure curve, a solid product (for example, AlCl3) is deposited at a low vacuum (760 [torr] to 10-2 [torr]) and a low temperature (about 20 [°C]) and adheres and accumulates on the inner side of the turbomolecular pump 100A. When the deposit of the process gas accumulates in the
turbomolecular pump 100, the accumulation may narrow the pump flow passage and degrade the performance of theturbomolecular pump 100. The above-mentioned product tends to solidify and adhere in areas with higher pressures, such as the vicinity of the outlet port and the vicinity of the threadedspacer 131. - To solve this problem, conventionally, a heater or annular water-cooled tube 149 (not shown) is wound around the outer circumference of the
base portion 129, and a temperature sensor (e.g., a thermistor, not shown) is embedded in thebase portion 129, for example. The signal of this temperature sensor is used to perform control to maintain the temperature of thebase portion 129 at a constant high temperature (preset temperature) by heating with the heater or cooling with the water-cooled tube 149 (hereinafter referred to as TMS (temperature management system)). - The
amplifier circuit 150 is now described that controls and excites the upperradial electromagnets 104, the lowerradial electromagnets 105, and theaxial electromagnets turbomolecular pump 100 configured as described above.FIG. 2 is a circuit diagram of theamplifier circuit 150. - In
FIG. 2 , one end of an electromagnet winding 151 forming an upperradial electromagnet 104 or the like is connected to apositive electrode 171a of apower supply 171 via atransistor 161, and the other end is connected to anegative electrode 171b of thepower supply 171 via acurrent detection circuit 181 and atransistor 162. Eachtransistor - In the
transistor 161, acathode terminal 161a of its diode is connected to thepositive electrode 171a, and ananode terminal 161b is connected to one end of the electromagnet winding 151. In thetransistor 162, acathode terminal 162a of its diode is connected to acurrent detection circuit 181, and ananode terminal 162b is connected to thenegative electrode 171b. - A diode 165 for current regeneration has a
cathode terminal 165a connected to one end of the electromagnet winding 151 and ananode terminal 165b connected to thenegative electrode 171b. Similarly, adiode 166 for current regeneration has acathode terminal 166a connected to thepositive electrode 171a and ananode terminal 166b connected to the other end of the electromagnet winding 151 via thecurrent detection circuit 181. Thecurrent detection circuit 181 may include a Hall current sensor or an electric resistance element, for example. - The
amplifier circuit 150 configured as described above corresponds to one electromagnet. Accordingly, when the magnetic bearing uses 5-axis control and has tenelectromagnets identical amplifier circuit 150 is configured for each of the electromagnets. These tenamplifier circuits 150 are connected to thepower supply 171 in parallel. - An
amplifier control circuit 191 may be formed by a digital signal processor portion (not shown, hereinafter referred to as a DSP portion) of thecontroller 200. Theamplifier control circuit 191 switches thetransistors - The
amplifier control circuit 191 is configured to compare a current value detected by the current detection circuit 181 (a signal reflecting this current value is referred to as acurrent detection signal 191c) with a predetermined current command value. The result of this comparison is used to determine the magnitude of the pulse width (pulse width time Tp1, Tp2) generated in a control cycle Ts, which is one cycle in PWM control. As a result, gate drive signals 191a and 191b having this pulse width are output from theamplifier control circuit 191 to gate terminals of thetransistors - Under certain circumstances such as when the rotational speed of the
rotating body 103 reaches a resonance point during acceleration, or when a disturbance occurs during a constant speed operation, therotating body 103 may require positional control at high speed and with a strong force. For this purpose, a high voltage of about 50 V, for example, is used for thepower supply 171 to enable a rapid increase (or decrease) in the current flowing through the electromagnet winding 151. Additionally, a capacitor is generally connected between thepositive electrode 171a and thenegative electrode 171b of thepower supply 171 to stabilize the power supply 171 (not shown). - In this configuration, when both
transistors - Also, when one of the
transistors amplifier circuit 150 in this manner reduces the hysteresis loss in theamplifier circuit 150, thereby limiting the power consumption of the entire circuit to a low level. Moreover, by controlling thetransistors turbomolecular pump 100 can be reduced. Furthermore, by measuring this freewheeling current with thecurrent detection circuit 181, the electromagnet current iL flowing through the electromagnet winding 151 can be detected. - That is, when the detected current value is smaller than the current command value, as shown in
FIG. 3 , thetransistors positive electrode 171a to thenegative electrode 171b via thetransistors - When the detected current value is larger than the current command value, as shown in
FIG. 4 , thetransistors negative electrode 171b to thepositive electrode 171a via thediodes 165 and 166. - In either case, after the pulse width time Tp1, Tp2 has elapsed, one of the
transistors amplifier circuit 150. - Referring to
FIGS. 5 to 16 , a first embodiment is now described. -
FIG. 5 is a schematic view showing an example of the configuration of the turbomolecular pump according to the first embodiment.FIG. 6 is a partially enlarged view of the turbomolecular pump according to the first embodiment shown inFIG. 5 . - In the first embodiment, one or both of an
inner rim 600 or anouter rim 700 of astator blade 123 have tapered surfaces (inner rim taperedsurface 610, outer rim tapered surface 710) that slope down toward the outlet port. - The tapered surface is provided in a section in which the rotor blade in one stage of the rotor blades in multiple stages has an outer diameter that is smaller at the side corresponding to the outlet port, or a section in which the rotor blade in one stage of the rotor blades in multiple stages has an inner diameter that is larger at the side corresponding to the outlet port. A
stator blade 123 having a tapered surface is arranged between these rotor blades. -
FIG. 7 is a diagram showing astator blade 123 according to the first embodiment A in which the inner rim has a tapered surface. - As shown in this figure, the
inner rim 600 has an inner rim taperedsurface 610 sloping down toward the outlet port. When molecules are transferred to and collide with the inner rim taperedsurface 610, the molecules are reflected at a right angle, hit by the rotor blade in the upper stage, and sent to the next stage. In this respect, theinner rim 600 having the inner rim taperedsurface 610 contributes to the exhaustion action. As is clear from the figure, theinner rim 600 and theouter rim 700 hold and fix theblades 550 of thestator blade 123. -
FIG. 8 is a diagram showing astator blade 123 according to the first embodiment B in which the inner rim has a tapered surface. Thestator blade 123 according to the first embodiment B has inner rimvertical surfaces 620 and inner rim circumference surfaces 630. - For example, the
stator blade 123 is made of aluminum and manufactured as a casting using a mold or by cutting. - When the
stator blade 123 is manufactured as a casting using a mold, the product needs to be removed from the mold. The inner rimvertical surfaces 620 are provided for this reason. The section under eachblade 550 in which an inner rimvertical surface 620 is formed has an innerrim circumference surface 630, which is parallel to theouter rim 700. -
FIG. 9 is a diagram showing astator blade 123 according to the first embodiment C in which the inner rim and the outer rim have tapered surfaces. As shown in this figure, not only theinner rim 600 but also theouter rim 700 has an outer rim taperedsurface 710 sloping down toward the outlet port. - In this first embodiment C, in addition to the
inner rim 600, theouter rim 700 also contributes to the exhaustion action. - In the first embodiment C, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the outer rim taperedsurface 710. -
FIG. 10 is a diagram showing astator blade 123 according to the first embodiment D in which the inner rim and the outer rim have tapered surfaces, vertical surfaces, and circumference surfaces. - As in the first embodiment B, outer rim
vertical surfaces 720 are provided because the product needs to be removed from a mold when it is manufactured as a casting using the mold. The section under eachblade 550 in which an outer rimvertical surface 720 is formed has an outerrim circumference surface 730, which is parallel to theinner rim 600. -
FIGS. 11A and 11B are diagrams showing astator blade 123 according to the first embodiment E in which the inner rim and the outer rim have tapered surfaces and the outer rim has a tapered surface above (below) the blades. - With the first embodiment E, the
inner rim 600 has the same shape as the first embodiment A and the first embodiment C, but the configuration of theouter rim 700 differs from that of the first embodiment C. That is, in the embodiment shown inFIG. 11A , the outer rim taperedsurface 710 extends above the surfaces of theblades 550, forming anextra portion 740. - In the embodiment shown in
FIG. 11B , the outer rim taperedsurface 710 extends to the lower side beyond the back surfaces of theblades 550, forming anextra portion 740. - This
extra portion 740 facilitates the setting of the axial dimension of thestator blade 123. That is, the adjustment in the height direction can be made within a range that does not affect theblades 550. - In this first embodiment E, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the outer rim taperedsurface 710. - The first embodiment E does not have a vertical surface and is therefore manufactured by cutting.
-
FIG. 12 is a diagram showing astator blade 123 according to the first embodiment F in which the inner rim and the outer rim have tapered surfaces and an inner circumference surface is provided above (below) the blades. - With this first embodiment F, the
inner rim 600 has the same shape as the first embodiment A and the first embodiment C, but the configuration of theouter rim 700 differs from that of the first embodiment C. That is, an outer riminner circumference surface 760 is formed above (below) the surfaces of theblades 550. Unlike the outer rim taperedsurface 710, the outer riminner circumference surface 760 is parallel to the axis of theturbomolecular pump 100. - By providing the outer rim inner circumference surfaces 760 and adjusting the dimension in the axial direction, the positioning in the axial direction is achieved when installing the
stator blade 123 in theturbomolecular pump 100. - In this first embodiment F, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the taperedsurface 710. - The first embodiment F does not have a vertical surface and is therefore manufactured by cutting.
-
FIG. 13 is a diagram showing astator blade 123 according to the first embodiment G in which the inner rim and the outer rim have tapered surfaces and vertical surfaces and an inner circumference surface is provided above (below) the blades of the outer rim. The difference between this embodiment G and the first embodiment F is that inner rimvertical surfaces 620 and outer rimvertical surfaces 720 are provided. - By providing the outer rim inner circumference surfaces 760 and adjusting the dimension in the axial direction, the positioning in the axial direction is achieved when installing the
stator blade 123 in theturbomolecular pump 100. - In this first embodiment G, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the outer rim taperedsurface 710. -
FIGS. 14A and 14B are diagrams showing astator blade 123 according to the first embodiment H in which the inner rim and the outer rim have tapered surfaces and vertical surfaces and the outer rim has a tapered surface above (below) the blades.FIG. 14A is an external view as seen from above, andFIG. 14B is an external view as seen from below. - The difference between this embodiment and the first embodiment E is that inner rim
vertical surfaces 620 and outer rimvertical surfaces 720 are provided. - The presence of the
extra portion 740 facilitates the setting of the axial dimension of thestator blade 123. - In this first embodiment H, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the taperedsurface 710. -
FIG. 15 is a diagram showing astator blade 123 according to the first embodiment I in which the inner rim and the outer rim have tapered surfaces and a flange is provided. - This embodiment I has a
flange 750 projecting outward (toward theouter cylinder 127 when installed) from theouter rim 700. - This
flange 750 allows thestator blade 123 to be positioned and held in the axial direction. That is, by adjusting the thickness (height in the axial direction) of theflange 750, the positioning in the axial direction of thestator blade 123 is achieved. Also, thisflange 750 is held so thestator blade 123 is fixed to theouter cylinder 127. - In this first embodiment I, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the outer rim taperedsurface 710. - The first embodiment I does not have a vertical surface and is therefore manufactured by cutting.
-
FIG. 16 is a diagram showing astator blade 123 according to the first embodiment J in which the inner rim and the outer rim have tapered surfaces and inner rim vertical surfaces, outer rim vertical surfaces and a flange is provided. - As in the embodiment I, this embodiment J has a
flange 750 projecting outward (toward theouter cylinder 127 when installed) from theouter rim 700. - This
flange 750 allows thestator blade 123 to be positioned and held in the axial direction. That is, by adjusting the thickness (height in the axial direction) of theflange 750, the positioning in the axial direction of thestator blade 123 is achieved. Also, thisflange 750 is held so thestator blade 123 is fixed to theouter cylinder 127. - The difference between this embodiment J and the first embodiment I is that inner rim
vertical surfaces 620 and outer rimvertical surfaces 720 are provided. - In this first embodiment J, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the outer rim taperedsurface 710. - A second embodiment is now described with reference to
FIGS. 17 to 21 . -
FIG. 17 is a partially enlarged view of a turbomolecular pump according to the second embodiment. - In this second embodiment, the
outer rim 700 of astator blade 123 has an outer rim taperedsurface 710, which slopes down toward the outlet port, and an outer riminner circumference surface 760. That is, theouter rim 700 has both the outer rim taperedsurface 710 and the outer riminner circumference surface 760. Theinner rim 600 is the same as that in the first embodiment. -
FIG. 18 is a diagram showing astator blade 123 according to the second embodiment A in which the outer rim has a tapered surface and an inner circumference surface. - The outer rim tapered
surface 710 is located at a position corresponding to theblades 550. The outer riminner circumference surface 760 is provided below the outer rim taperedsurface 710. This outer riminner circumference surface 760 is not inclined and is parallel to the axis of theturbomolecular pump 100. - The positioning of the
stator blade 123 is achieved by adjusting the outer riminner circumference surface 760 in the height direction. The absence of ablade 550 in the position corresponding to the outer riminner circumference surface 760 facilitates the adjustment. - In this second embodiment A, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the outer rim taperedsurface 710. - The second embodiment A does not have a vertical surface and is therefore manufactured by cutting.
-
FIG. 19 is a diagram showing astator blade 123 according to the second embodiment B in which the outer rim has a tapered surface, an inner circumference surface, and a flange. - The outer rim tapered
surface 710 is located at a position corresponding to theblades 550. The outer riminner circumference surface 760 is provided below the outer rim taperedsurface 710. - The difference between the second embodiment B and the second embodiment A is that the
outer rim 700 has aflange 750 projecting outward (toward theouter cylinder 127 when installed). - This
flange 750 allows thestator blade 123 to be positioned and held in the axial direction. That is, by adjusting the thickness (height in the axial direction) of theflange 750, the positioning in the axial direction of thestator blade 123 is achieved. Also, thisflange 750 is held so thestator blade 123 is fixed to theouter cylinder 127. - In this second embodiment B, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the outer rim taperedsurface 710. - The second embodiment B does not have a vertical surface and is therefore manufactured by cutting.
-
FIG. 20 is a diagram showing astator blade 123 according to the second embodiment C in which the outer rim has a tapered surface and an inner circumference surface and inner rim vertical surfaces and outer rim vertical surface are provided. - The outer rim tapered
surface 710 is located at a position corresponding to theblades 550. The outer riminner circumference surface 760 is provided below the outer rim taperedsurface 710. - The difference between this second embodiment C and the second embodiment A is that the inner rim
vertical surface 630 and the outer rimvertical surface 720 are provided because the product needs to be removed from a mold when it is manufactured as a casting using the mold. - In this second embodiment C, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the outer rim taperedsurface 710. -
FIG. 21 is a diagram showing astator blade 123 according to the second embodiment D in which the outer rim has a tapered surface, an inner circumference surface, and a flange. - The outer rim tapered
surface 710 is located at a position corresponding to theblades 550. The outer riminner circumference surface 760 is provided below the outer rim taperedsurface 710. - The difference between the second embodiment D and the second embodiment C is that the
outer rim 700 has aflange 750 projecting outward (toward theouter cylinder 127 when installed). - This
flange 750 allows thestator blade 123 to be positioned and held in the axial direction. That is, by adjusting the thickness (height in the axial direction) of theflange 750, the positioning in the axial direction of thestator blade 123 is achieved. Also, thisflange 750 is held so thestator blade 123 is fixed to theouter cylinder 127. - In this second embodiment D, the
inner rim 600 and theouter rim 700 each have a tapered surface (610, 710), but only theouter rim 700 may have the outer rim taperedsurface 710. - Referring to
FIG. 22 , a third embodiment is now described. -
FIG. 22 is a partially enlarged view of a turbomolecular pump according to the third embodiment. - In this third embodiment, the
stator blades 123 used in the first embodiment are arranged reversely or in the same orientation. At least thestator blade 123 in the last stage is reversely arranged. - By arranging the
stator blades 123 in this manner, the products of the same size (the stator blades 123) may be used for different functions, reducing the manufacturing costs. - Additionally, since the outer rim tapered
surfaces 710 are continuously connected, a gap is not formed with respect to the spacer. - A fourth embodiment is now described with reference to
FIGS. 23 to 25 . -
FIG. 23 is a partially enlarged view of a turbomolecular pump according to the fourth embodiment. - In this fourth embodiment, the
inner rim 600 of astator blade 123 has an inner rim taperedsurface 610 sloping down toward the outlet port. That is, theinner rim 600 that is located in a section in which the diameter at the bases of theblades 550 of thestator blade 123 on the upstream side is smaller than the diameter at the bases of theblades 550 of thestator blade 123 on the downstream side has an inner rim taperedsurface 610. -
FIG. 24 is a diagram showing astator blade 123 according to the fourth embodiment A in which theinner rim 600 has an inner rim taperedsurface 610. Theinner rim 600 shown inFIG. 24 is manufactured by cutting because it does not have inner rimvertical surfaces 620. -
FIG. 25 is a diagram showing astator blade 123 according to the fourth embodiment B in which theinner rim 600 has an inner rim taperedsurface 610 and inner rim vertical surfaces. Theinner rim 600 shown inFIG. 25 is manufactured by casting using a mold because it has the inner rimvertical surfaces 620. -
FIGS. 24 and25 both show a type ofstator blade 123 without anouter rim 700, but the fourth embodiment can also be applied to a type ofstator blade 123 with anouter rim 700. - A fifth embodiment is now described with reference to
FIGS. 26 to 28 . -
FIG. 26 is a partially enlarged view of a turbomolecular pump according to the fifth embodiment. - This fifth embodiment relates to a
stator blade spacer 800 having a statorblade spacer portion 870 that holds the side of astator blade 123 corresponding to theouter frame 127 and enables the positioning of thestator blades 123 in the height direction. -
FIG. 27 (the fifth embodiment A) andFIG. 28 (the fifth embodiment B) are diagrams each showing the appearance of astator blade spacer 800. As shown in these figures, thestator blade spacer 800 hasprotrusions 860 extending in the height direction from thespacer portion 870 within the range of thestator blade 123 in the height direction. At least a part of theinner circumference surface 830 of the statorblade spacer portion 870 and theprotrusions 860 has a stator blade spacer taperedsurface 810 sloping down toward the outlet port. Theinner circumference surface 830 of the statorblade spacer portion 870 and the range in which theprotrusions 860 extend within the range of thestator blade 123 in the height direction are also defined as the "outer circumference portion of the stator blade". - Blade
fitting grooves 820, to which theblades 550 of astator blade 123 is fitted and held when installed, are provided between theprotrusions 860. - The
stator blade spacer 800 shown inFIG. 28 further has a statorblade spacer flange 850. The statorblade spacer flange 850 enables the positioning of thestator blade spacer 800 in the height direction. Moreover, thestator blade spacer 800 can be held and fixed by holding the statorblade spacer flange 850. - The angles of the tapered surfaces in the first to fifth embodiments are now described.
- There is no limitation to the angle of a tapered surface as long as the tapered surface (inclined surface) slopes down toward the outlet port.
-
FIG. 29A is a cross-sectional view of astator blade 123 corresponding to the first embodiment H. In the example shown in this figure, the tapered surface of thestator blade 123 is at the angle of the line (imaginary line) connecting the inner circumference lower end A of astator blade spacer 125 to the inner circumference upper end B of astator blade spacer 125. -
FIG. 29B is a cross-sectional view of astator blade 123 corresponding to the second embodiment D. In the example shown in this figure, the tapered surface of thestator blade 123 is at the angle of the line (imaginary line) connecting the point of intersection H of a perpendicular drawn from the distal end X of theupper rotor blade 102 to thelower stator blade 123 to the point at (1) the basal end of ablade 550 of thestator blade 123 or (2) the inner circumference lower side of thestator blade 123. - As described above, the tapered surface may have various angles, and the angle may be appropriately determined according to various conditions.
- In each embodiment, other than a tapered surface, a gently curved surface may also be used.
- The embodiments and modifications of the present invention may be combined as necessary.
- The invention is amenable to various modifications without departing from the spirit of the invention. The invention is, of course, intended to cover all modifications.
-
- 100
- Turbomolecular pump
- 101
- Inlet port
- 102
- Rotor blade
- 103
- Rotating body
- 113
- Rotor shaft
- 123
- Stator blade
- 125
- Stator blade spacer
- 127
- Outer cylinder
- 129
- Base portion
- 133
- Outlet port
- 200
- Controller
- 550
- Blade
- 600
- Inner rim
- 610
- Inner rim tapered surface
- 620
- Inner rim vertical surface
- 630
- Inner rim circumference surface
- 700
- Outer rim
- 710
- Outer rim tapered surface
- 720
- Outer rim vertical surface
- 730
- Outer rim circumference surface
- 740
- Extra portion
- 750
- Flange
- 760
- Outer rim inner circumference surface
- 800
- Stator blade spacer
- 810
- Stator blade spacer tapered surface
- 820
- Blade fitting groove
- 830
- Stator blade spacer inner circumference surface
- 850
- Stator blade spacer flange
- 860
- Protrusion
- 870
- Stator blade spacer portion
Claims (8)
- A vacuum pump comprising:a casing that has an inlet port and an outlet port;a rotating shaft that is rotationally supported inside the casing;rotor blades in multiple stages that are fixed to the rotating shaft and rotatable together with the rotating shaft; andstator blades in multiple stages that are fixed to the casing and located between the rotor blades,the rotor blade in at least one stage of the rotor blades in multiple stages being configured to have an outer diameter that is smaller at an outlet port side than at an inlet port side, or the rotor blade in at least one stage of the rotor blades in multiple stages being configured to have an inner diameter that is larger at the outlet port side than at the inlet port side, whereinan outer circumference portion or an inner circumference portion of the stator blade that is located immediately above the rotor blade having a smaller outer diameter or immediately above the rotor blade having a larger inner diameter has a tapered surface sloping down to the outlet port side.
- The vacuum pump according to claim 1, wherein,the stator blade includes a plurality of radially arranged blades and an inner rim or an outer rim that holds the plurality of blades, andan outer circumference surface of the inner rim or an inner circumference surface of the outer rim has a tapered surface sloping down to the outlet port side.
- The vacuum pump according to claim 1, whereinthe stator blade includes a plurality of radially arranged blades and a spacer portion that holds the plurality of blades and enables positioning of the stator blade in a height direction, andan inner circumference surface of the spacer portion has a tapered surface sloping down to the outlet port side.
- The vacuum pump according to claim 2 or 3, wherein the stator blade is undercut to surfaces of the plurality of blades facing the outlet port side.
- The vacuum pump according to claim 2 or 3, wherein the stator blade has a vertical surface or a tapered surface on a rear side of the plurality of blades.
- The vacuum pump according to claim 1, whereina protrusion is provided that extends within a range of the stator blade in a height direction from a spacer portion that holds a casing side of the stator blade and enables positioning of the stator blade in the height direction, andat least a part of an inner circumference surface of the spacer portion and the protrusion has a tapered surface sloping down to the outlet port side.
- A stator blade for a vacuum pump including a casing having an inlet port and an outlet port, the stator blade comprising:a plurality of blades arranged radially; andan inner rim or an outer rim holding the plurality of blades, whereinan outer circumference surface of the inner rim or an inner circumference surface of the outer rim has a tapered surface sloping down toward an outlet port side.
- A spacer for a vacuum pump including a casing having an inlet port and an outlet port, the spacer including:a spacer portion that is configured to, when a stator blade having a plurality of radially arranged blades is placed, hold a casing side of the stator blade and enable positioning of the stator blade in a height direction; anda protrusion that extends from the spacer portion within a range of the stator blade in the height direction, whereinat least a part of an inner circumference surface of the spacer portion and the protrusion has a tapered surface sloping down to the outlet port side.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2020140495A JP2022035881A (en) | 2020-08-21 | 2020-08-21 | Vacuum pump, fixed blade and spacer |
PCT/JP2021/028253 WO2022038996A1 (en) | 2020-08-21 | 2021-07-30 | Vacuum pump, fixed blade, and spacer |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4202227A1 true EP4202227A1 (en) | 2023-06-28 |
Family
ID=80322644
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP21858144.5A Pending EP4202227A1 (en) | 2020-08-21 | 2021-07-30 | Vacuum pump, fixed blade, and spacer |
Country Status (7)
Country | Link |
---|---|
US (1) | US20230323890A1 (en) |
EP (1) | EP4202227A1 (en) |
JP (1) | JP2022035881A (en) |
KR (1) | KR20230050310A (en) |
CN (1) | CN115803530A (en) |
IL (1) | IL300054A (en) |
WO (1) | WO2022038996A1 (en) |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19937392A1 (en) * | 1999-08-07 | 2001-02-08 | Leybold Vakuum Gmbh | Friction vacuum pump with active pump elements |
DE10338222A1 (en) * | 2003-08-20 | 2005-03-10 | Leybold Vakuum Gmbh | Combined drive with storage |
JP4749054B2 (en) | 2005-06-22 | 2011-08-17 | エドワーズ株式会社 | Turbomolecular pump and method of assembling turbomolecular pump |
JP7015106B2 (en) | 2016-08-30 | 2022-02-02 | エドワーズ株式会社 | Vacuum pumps and rotating cylinders included in vacuum pumps |
JP6782141B2 (en) * | 2016-10-06 | 2020-11-11 | エドワーズ株式会社 | Vacuum pumps, as well as spiral plates, spacers and rotating cylinders on vacuum pumps |
JP6882624B2 (en) * | 2017-09-25 | 2021-06-02 | 株式会社島津製作所 | Turbo molecular pump |
-
2020
- 2020-08-21 JP JP2020140495A patent/JP2022035881A/en active Pending
-
2021
- 2021-07-30 CN CN202180049707.XA patent/CN115803530A/en active Pending
- 2021-07-30 KR KR1020237000181A patent/KR20230050310A/en unknown
- 2021-07-30 IL IL300054A patent/IL300054A/en unknown
- 2021-07-30 WO PCT/JP2021/028253 patent/WO2022038996A1/en unknown
- 2021-07-30 EP EP21858144.5A patent/EP4202227A1/en active Pending
- 2021-07-30 US US18/006,290 patent/US20230323890A1/en active Pending
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Publication number | Publication date |
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WO2022038996A1 (en) | 2022-02-24 |
JP2022035881A (en) | 2022-03-04 |
CN115803530A (en) | 2023-03-14 |
KR20230050310A (en) | 2023-04-14 |
IL300054A (en) | 2023-03-01 |
US20230323890A1 (en) | 2023-10-12 |
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