Magnetic bearing device, turbomolecular pump, and control method for

Abstract

A magnetic bearing device including a rotating body, a magnetic bearing portion which levitates the rotating body in air and supports the rotating body by a magnetic force, and a control portion which controls drive of the magnetic bearing portion, in which the control portion includes a tuning portion which tunes the magnetic bearing portion, a power-source detecting portion which detects a state of a power source of the magnetic bearing device, and a stationary-levitated detecting portion which detects whether the rotating body is in a stationary-levitated state or not, and the tuning portion is configured to perform tuning of the magnetic bearing portion at least in either one of (A) a case where the power-source detecting portion detects that a power source of the magnetic bearing device has been switched from OFF to ON, and (B) a case where the stationary-levitated detecting portion detects that the rotating body is in the stationary-levitated state.

Description

MAGNETIC BEARING DEVICE, TURBOMOLECULAR PUMP, AND CONTROL METHOD FOR MAGNETIC BEARING PORTION

[0001] The present application relates to a magnetic bearing device, a turbomolecular pump, and a control method for a magnetic bearing portion.

[0002] A background art of this technical field is, for instance, Japanese Patent Application Publication No. 2000-240649 (PTL 1). This gazette discloses that "A magnetic bearing main-body 20 includes a resistor 412 for specifying a model and a main body EEP-ROM 411 in which models and various characteristic values are stored. A control device 40 includes a device EEP-ROM 401 which stores the models and various characteristics and a ROM table 402 which stores the various characteristics corresponding to a plurality of the models. A control device 400 updates the device EEP-ROM 401 to contents of the main body EEP-ROM 411 when both the various characteristics of the main body EEP- ROM 411 and the various characteristics of the device EEP-ROM 401 are normal but both the various characteristics are not the same" (see Abstract).

[0003] [PTL 1] Japanese Patent Application Publication No. 2000-240649

[0004] According to a configuration of the PTL 1, even if a model of a magnetic bearing main-body 20 is changed, various characteristics thereof are automatically adjusted, and the adjustment by specialized engineers is not needed. However, the various characteristics need to be recorded in EEP-ROM, with regard to both the main body and the control device.

[0005] In order to solve the aforementioned problem, a configuration described in the scope of claim is adopted, for example. This application includes a plurality of means for solving the aforementioned problem, but when one example thereof is cited, it is a device with a magnetic bearing, or magnetic bearing device, including: a rotating body; a magnetic bearing portion which levitates and supports the rotating body by a magnetic force; and a control portion which controls drive of the magnetic bearing portion, in which the control portion includes: a tuning portion which tunes the magnetic bearing portion;a power-source detecting portion which detects a state of a power source of the magnetic bearing device; and a stationary-levitated detecting portion which detects whether the rotating body is in a stationary-levitated state or not; and the tuning portion is configured such that the tuning of the magnetic bearing portion is performed at least in either one of (A) a case where the power-source detecting portion detects that the power source of the magnetic bearing device has been switched from OFF to ON; and (B) a case where the stationary-levitated detecting portion detects that the rotating body is in the stationary-levitated state.

[0006] According to the present invention, even if the various characteristic values are not recorded, the rotating body can be operated in a state where the various characteristic values are adjusted. Problems, configurations and advantageous effects other than the above will be made clear from the explanation of the following Embodiments.

[0007] [Fig. 1] Fig. 1 is an example of a vertical sectional view of a turbomolecular pump. [Fig. 2] Fig. 2 is an example of a circuit diagram of an amplifier circuit for rotor-shaft control of the turbomolecular pump. [Fig. 3] Fig. 3 is an example of a time chart showing control when an electric- current instruction value is larger than a detected value. [Fig. 4] Fig. 4 is an example of a time chart showing control when the electric- current instruction value is smaller than the detected value. [Fig. 5] Fig. 5 is an example of a hardware configuration of a control devicean Embodiment. [Fig.Fig. 6 is a diagram showing a flow of information of the turbomolecular pump according to the Embodiment. [Fig. 7]Fig.7 is a flow chart of an entire operation of the turbomolecular pump according to the Embodiment. [Fig. 8] Fig. 8 is a tuning control flow (power ON) according to the Embodiment. [Fig. 9] Fig. 9 is a tuning control flow (stationary levitating) according to the Embodiment. [Fig. 10] Fig. 10 is a stationary-levitated state determination flow according to the Embodiment. [Fig. 11] Fig. 11 is the tuning control flow (stationary levitating) according to another Embodiment. [Fig. 12] Fig. 12 is an example of a vertical sectional view of the turbomolecular pump according to another Embodiment. [Fig. 13] Fig. 13 is an example of a hardware configuration of the control device according to the Embodiment. [Fig. 14] Fig. 14 is a block diagram showing an example of a circuit constituting a disassembly detecting portion of the turbomolecular pump. [Fig. 15] Fig. 15 is the tuning control flow (power ON) according to another Embodiment.

[0008] Hereinafter, a vacuum pump according to an Embodiment will be explained on the basis of drawings. Some of the drawings indicate an X- axis, a Y-axis, and a Z-axis, and each axis is drawn so as to be directions in common in each drawing. However, these are only directions for convenience of the explanation and do not limit an installation form of the vacuum pump in any way. Moreover, the same member is given a sign in one drawing, and the signs are omitted in the other drawings in some cases.

[0009] [Embodiment 1] <Basic Configuration of Turbomolecular Pump> Fig. 1 shows a basic configuration of a turbomolecular pump 1, which is an example of a vacuum pump. The turbomolecular pump 1 roughlyincludes a pump main body 100 and a control device 200. In this turbomolecular pump 1, an upper side in Fig. 1 is an upstream (sucking) side and is configured such that a vacuum chamber (not shown) of a target device such as a semiconductor manufacturing device or the like is connected to an inlet port 101, for example. Moreover, in the turbomolecular pump 1, a lower side in Fig. 1 is a downstream (exhaust) side and is configured such that an auxiliary pump (not shown), for example, is connected to an outlet port 133. This turbomolecular pump 1 can be used in a reverse vertical attitude, a horizontal attitude, and an inclined attitude in addition to a perpendicular attitude in a vertical direction as shown in Fig. 1

[0010] A vertical sectional view of this turbomolecular pump 1 is shown in Fig. 1. Moreover, a flow of information in the turbomolecular pump 1 is shown in Fig. 6. In Fig. 1, the pump main body 100 has the inlet port 101 formed on an upper end of a cylindrical outer cylinder 127. And inside the outer cylinder 127, a rotating body 103 on which a plurality of rotor blades 102 (102a, 102b, 102c ...), which are turbine blades for sucking / exhausting a gas, are formed radially and in multiple stages on a peripheral part is provided. At a center of this rotating body 103, a rotor shaft 113 is mounted, and this rotor shaft 113 is levitated / supported in the air and position-controlled by a magnetic bearing of 5-axis control, for example. The rotating body 103 is constituted in general by metal such as aluminum or an aluminum alloy.

[0011] As upper-side radial-direction electromagnets 104, four electromagnets are disposed by making a pair in an X-axis and a Y-axis. Close to the upper-side radial-direction electromagnets 104 and corresponding each of the upper-side radial-direction electromagnets 104, four upper-side radial-direction sensors 107 are provided. As the upper- side radial-direction sensor 107, an inductance sensor having a conductive wiring, an eddy-current sensor or the like is used, and a position of the rotor shaft 113 is detected on the basis of a change in the inductance of the conductive wiring changing accordingly to the position of the rotor shaft 113. This upper-side radial-direction sensor 107 is configured to detect displacement in the radial direction of the rotor shaft 113, that is, the displacement in the radial direction of the rotating body 103 fixed thereto and to send it to the control device 200.

[0012] In this control device 200, a compensation circuit (see a compensation module 218 in Fig. 6) having a PID adjustment function, for example, generates an excitation-control instruction signal of the upper- side radial-direction electromagnet 104 on the basis of a position signal detected by the upper-side radial-direction sensor 107, and an amplifier circuit 150 (which will be described later) shown in Fig. 2 excites / controls the upper-side radial-direction electromagnet 104 on the basis of this excitation-control instruction signal so that the radial- direction position on the upper side of the rotor shaft 113 is adjusted.

[0013] And this rotor shaft 113 is formed of a high-permeability material (such as iron, stainless or the like) or the like and is attracted by a magnetic force of the upper-side radial-direction electromagnet 104. Such adjustment is performed independently in the X- axis direction and in the Y-axis direction, respectively. Moreover, a lower-side radial-direction electromagnet 105 and a lower-side radial- direction sensor 108 are disposed similarly to the upper-side radial- direction electromagnet 104 and the upper-side radial-direction sensor 107 and adjust the radial-direction position on the lower side or the rotor shaft 113 similarly to the radial-direction position on the upper side.

[0014] Furthermore, the axial-direction electromagnets 106A, 106B are disposed by vertically sandwiching a disc-shaped metal disc 111 provided on a lower part of the rotor shaft 113. The metal disc 111 is constituted by a high-permeability material such as iron. An axial-direction sensor 109 is provided for detecting displacement in the axial direction of the rotor shaft 113 and is configured to send the axial-direction position signal thereof to the control device 200.

[0015] Then, in the control device 200, a compensation circuit having the PID adjustment function, for example, generates an excitation-control instruction signal for each of the axial-direction electromagnet 106A and the axial-direction electromagnet 106B on the basis of the axial- direction position signal detected by the axial-direction sensor 109, and the amplifier circuit 150 excites / controls the axial-direction electromagnet 106A and the axial-direction electromagnet 106B, respectively, on the basis of these excitation-control instruction signals, whereby the axial-direction electromagnet 106A attracts the metal disc 111 upward by the magnetic force, and the axial-directionelectromagnet 106B attracts the metal disc 111 downward, and the axial- direction position of the rotor shaft 113 is adjusted.

[0016] As described above, the control device 200 is configured to adjust the magnetic force of the axial-direction electromagnets 106A, 106B exerted on the metal disc 111 adequately so that the rotor shaft 113 is magnetically levitated in the axial direction and is held in a space in a non-contact manner. Note that the amplifier circuit 150 which excites / controls the upper-side radial-direction electromagnet 104, the lower-side radial-direction electromagnet 105, and the axial-direction electromagnets 106A, 106B will be described later.

[0017] On the other hand, a motor 121 includes a plurality of magnetic poles disposed circumferentially so as to surround the rotor shaft 113. Each of the magnetic poles is controlled by the control device 200 so as to rotate / drive the rotor shaft 113 via an electromagnetic force acting between them and the rotor shaft 113. Moreover, in the motor 121, a rotation-speed sensor 115 (see Fig. 6) such as a Hall element, a resolver or an encoder is incorporated, and the rotation speed of the rotor shaft 113 is detected by a detection signal of this rotation-speed sensor 115.

[0018] Furthermore, in the vicinity of the lower-side radial-direction sensor 108, for example, a phase sensor, not shown, is mounted and is configured to detect a phase of rotation of the rotor shaft 113. In the control device 200, detection signals of the phase sensor and the rotation-speed sensor 115 are used together so as to detect a position of the magnetic pole.

[0019] A plurality of stator blades 123 (123a, 123b, 123c, ...) are disposed with a slight gap from the rotor blades 102 (102a, 102b, 102c, ...). Since each of the rotor blades 102 (102a, 102b, 102c, ...) transfers molecules of the exhaust gas to a lower direction by collision, it is formed by being inclined only by a predetermined angle from a plane perpendicular to an axis of the rotor shaft 113. The stator blades 123 (123a, 123b, 123c, ...) are constituted by metal such as aluminum, iron, stainless, copper and the like or an alloy containing these metals as components, for example.

[0020] Moreover, the stator blades 123 are also formed by being inclined only by a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 and are disposed alternately with the steps of the rotor blades 102 toward the inside of the outer cylinder 127. Andouter peripheral ends of the stator blades 123 are supported in a state fitted and inserted between a plurality of stator-blade spacers 125 (125a, 125b, 125c, ...) stacked.

[0021] The stator-blade spacers 125 are ring-shaped members and are constituted by metal such as aluminum, iron, stainless and the like or an alloy containing these metals as components, for example. On an outer periphery of the stator-blade spacer 125, the outer cylinder 127 is fixed with a slight gap between them. On a bottom part of the outer cylinder 127, a base portion 129 is disposed. On the base portion 129, the outlet port 133 is formed and communicates with the outside. The exhaust gas having entered the inlet port 101 from a chamber (vacuum chamber) side and transferred to the base portion 129 is sent to the outlet port 133.

[0022] Furthermore, depending on an application of the turbomolecular pump 1, a threaded spacer 131 is disposed between a lower part of the stator-blade spacer 125 and the base portion 129. The threaded spacer 131 is a cylindrical member constituted by metal such as aluminum, copper, stainless, iron or an alloy containing these metals as components, and a plurality of spiral thread grooves 131a are engraved in an inner peripheral surface thereof. A direction of the spiral of the thread groove 131a is a direction in which, when the molecules of the exhaust gas move in a rotating direction of the rotating body 103, the molecules are transferred toward the outlet port 133. At a lowest part continuing to the rotor blades 102 (102a, 102b, 102c, ...) of the rotating body 103, a cylinder portion 102d is suspended. An outer peripheral surface of this cylinder portion 102d is cylindrical and extended toward the inner peripheral surface of the threaded spacer 131 and is closer to the inner peripheral surface of this threaded spacer 131 with a predetermined gap. The exhaust gas having been transferred to the thread groove 131a by the rotor blades 102 and the stator blades 123 is sent to the base portion 129 by being guided by the thread groove 131a.

[0023] The base portion 129 is a disc-shaped member constituting a bottom part of the pump main body 100 and is constituted in general bymetal stainless 129pump body also functions as a conduction path of a heat and thus, metal having rigidity and high heat conductivity such as iron, aluminum, copper and the like is preferably used.

[0024] In the configuration as above, when the rotor blades 102 are rotated / driven together with the rotor shaft 113 by the motor 121, by means of an action of the rotor blade 102 and the stator blade 123, the exhaust gas is sucked from the chamber through the inlet port 101. A rotation speed of the rotor blade 102 is 20000 rpm to 90000 rpm, and a peripheral speed at a distal end of the rotor blade 102 reaches 200 m / s to 400 m / s. The exhaust gas sucked from the inlet port 101 passes between the rotor blade 102 and the stator blade 123 and is transferred to the base portion 129. At this time, a temperature of the rotor blade 102 rises by a friction heat generated when the exhaust gas is brought into contact with the rotor blade 102 or conduction of the heat generated in the motor 121, and this heat is conducted to the stator blade 123 side by radiation or conduction by gas molecules of the exhaust gas and the like.

[0025] The stator-blade spacers 125 are joined to each other on the outer peripheral part and conduct a heat received by the stator blade 123 from the rotor blade 102 and the frictional heat generated when the exhaust gas is brought into contact with the stator blade 123 or the like to the outside.

[0026] Note that it was explained in the above that the threaded spacer 131 is disposed on the outer periphery of the cylinder portion 102d of the rotating body 103, and the thread groove 131a is engraved in the inner peripheral surface of the threaded spacer 131. However, to the contrary, the thread groove is engraved in the outer peripheral surface of the cylinder portion 102d, and the spacer having a cylindrical inner peripheral surface around it is disposed in some cases.

[0027] Moreover, depending on the application of the turbomolecular pump 1, the periphery of an electric equipment part is covered with a stator column 122, and an inside of this stator column 122 is held at a predetermined pressure with a purge gas in some cases so that a gas sucked through the inlet port 101 does not intrude into the electric equipment part constituted by the upper-side radial-direction electromagnet 104, the upper-side radial-direction sensor 107, the motor121, the 105, the lower-side106B, the axial-direction sensor 109 and the like.

[0028] In this case, a piping, not shown, is disposed in the base portion 129, and the purge gas is introduced through this piping. Theintroduced purge gas is sent out to the outlet port 133 through gaps between a protective bearing 120 and the rotor shaft 113, between a rotor and a stator of the motor 121, and between the stator column 122 and an inner-peripheral side cylinder portion of the rotor blade 102.

[0029] Here, the turbomolecular pump 1 requires specification of a model and control based on specific parameters (various characteristics corresponding to models, for example) adjusted individually. In order to store the control parameters, the turbomolecular pump 1 includes an electronic circuit portion 141 inside the main body 100 thereof in general. However, in the turbomolecular pump 1 according to this art, the electronic circuit portion 141 does not store specific control parameters or individual identification information for identifying an individual unit of the pump main body 100. The electronic circuit portion 141 is typically constituted by semiconductor memories such as EEP-ROM, electronic components such as semiconductor elements for accesses thereof, and boards 143 for mounting them and the like. This electronic circuit portion 141 is accommodated in a lower part of the rotation-speed sensor 115 provided in the vicinity of a center, for example, of the base portion 129 constituting the lower part of the pump main body 100 and is closed by an air-tight bottom lid 145.

[0030] By the way, in a manufacturing process of a semiconductor, some of process gases introduced into the chamber have such natures that pressures are higher than a predetermined value, or when the temperatures thereof become lower than the predetermined value, they become solid. Inside the pump main body 100, the pressure of the exhaust gas is the lowest at the inlet port 101 and the highest at the outlet port 133. In the middle of transfer of the process gas from the inlet port 101 to the outlet port 133, if the pressure thereof becomes higher than the predetermined value or the temperature thereof becomes lower than the predetermined value, the process gas becomes solid, adheres to the inside of the pump main body 100, and deposits thereon.

[0031] If SiCl4 is used as a process gas in an Al etching device, for example, at a low vacuum (760 [torr] to 10-2 [torr]) and a low temperature (approximately 20 [ºC]), it is known from a steam pressure curve that a solid product (AlCl3, for example) precipitates and adheres and deposits on the inside of the pump main body 100. As a result, when the precipitates of the process gas deposit on the inside of the pumpmain body 100, the deposits narrow a flow passage of the pump and cause performances of the turbomolecular pump 1 to lower. And the aforementioned product is easily coagulated and adheres at a part with a high pressure in the vicinity of the outlet port 133 or the threaded spacer 131.

[0032] Thus, in order to solve this problem, conventionally, a heater, not shown, or an annular water cooling pipe 149 is wound around an outer periphery of the base portion 129 or the like, a temperature sensor (thermistor, for example), not shown, is embedded in the base portion 129, for example, and control of heating by a heater or cooling by the water cooling pipe 149 in order to keep the temperature of the base portion 129 at a certain high temperature (set temperature) on the basis of a signal of this temperature sensor is executed (hereinafter, referred to as TMS. TMS: Temperature Management System).

[0033] Subsequently, regarding the turbomolecular pump 1 constituted as above, the amplifier circuit 150 which excites / controls the upper-side radial-direction electromagnet 104, the lower-side radial-direction electromagnet 105, and the axial-direction electromagnets 106A, 106B will be explained. A circuit diagram of this amplifier circuit 150 is shown in Fig. 2.

[0034] In Fig. 2, an electromagnet wiring 151 constituting the upper- side radial-direction electromagnet 104 or the like has one end thereof connected to a positive pole 171a of the power source 171 through a transistor 161, while the other end thereof is connected to a negative pole 171b of the power source 171 through a current detection circuit 181 and a transistor 162. And the transistors 161, 162 are so-called power MOSFET, which has a structure in which a diode is connected between source-drain thereof.

[0035] At this time, the transistor 161 is configured such that a cathode terminal 161a of the diode is connected to the positive pole 171a and an anode terminal 161b is connected to one end of the electromagnet wiring 151. Moreover, the transistor 162 is configured such that a cathode terminal 162a of the diode is connected to the current detectioncircuit 181 anode pole171b.

[0036] On the other hand, a diode 165 for current regeneration is configured such that a cathode terminal 165a thereof is connected to oneend of the electromagnet wiring 151 and an anode terminal 165b thereof is connected to the negative pole 171b. Moreover, similarly to the above, a diode 166 for current regeneration is configured such that a cathode terminal 166a thereof is connected to the positive pole 171a and an anode terminal 166b thereof is connected to the other end of the electromagnet wiring 151 through the current detection circuit 181. And the current detection circuit 181 is constituted by a Hall-sensor type current sensor or an electric resistance element, for example.

[0037] The amplifier circuit 150 constituted as above is configured to correspond to one electromagnet. Thus, when the magnetic bearing is 5- axis control, and the number of the electromagnets 104, 105, 106A, 106B is 10 in total, the similar amplifier circuit 150 is constituted for each of the electromagnets, and ten units of the amplifier circuits 150 are connected in parallel with the power source 171.

[0038] Moreover, an amplifier control circuit 191 is constituted by a digital signal processor portion (Hereinafter, referred to as a DSP portion. DSP: Digital Signal Processor) of the control device 200, for example, and this amplifier control circuit 191 is configured to switch on / off the transistors 161, 162.

[0039] 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 called a current detection signal 191c) and a predetermined current instruction value. And on the basis of this comparison result, it is configured such that a magnitude of a pulse width (pulse-width times Tp1, Tp2) generated in a control cycle Ts, which is one cycle by PWM control, is determined. As a result, gate drive signals 191a, 191b having this pulse width are configured to be output from the amplifier control circuit 191 to gate terminals of the transistors 161, 162.

[0040] Note that, when passing a resonant point during an acceleration operation of a rotation speed of the rotating body 103 or if disturbance occurs during a constant-speed operation and the like, position control of the rotating body 103 at a high speed and with strong power is required. Thus, as the power source 171, it is configured that a voltage of approximately 50V, for example, is used so that a current flowing through the electromagnet wiring 151 can be rapidly increased (or decreased). Moreover, between the positive pole 171a and the negativepole 171b of the power source 171, a capacitor is usually connected in order to stabilize the power source 171 (not shown).

[0041] In the configuration as above, when the transistors 161, 162 are both turned on, the current flowing through the electromagnet wiring 151 (hereinafter, referred to as an electromagnet current iL) increases, while when both of the transistors are turned off, the electromagnet current iL decreases.

[0042] Moreover, when either one of the transistors 161, 162 is turned on, while the other is turned off, a so-called flywheel current is held. And by causing the flywheel current to flow through the amplifier circuit 150 as above, a hysteresis loss in the amplifier circuit 150 is decreased, and power consumption as the entire circuit can be kept low. Moreover, by controlling the transistors 161, 162 as above, a high- frequency noise such as a harmonic generated in the turbomolecular pump 1 can be reduced. Furthermore, by measuring this flywheel current by the current detection circuit 181, the electromagnet current iL flowing through the electromagnet wiring 151 can be detected.

[0043] That is, when the detected current value is smaller than the current instruction value, both the transistors 161, 162 are turned on only for a period of time corresponding to the pulse-width time Tp1 only once during the control cycle Ts example) as shown in Fig. 3. Thus, the electromagnet current iL during this period increases toward a current value iLmax (not shown) that can be made to flow from the positive pole 171a to the negative pole 171b through the transistors 161, 162.

[0044] On the other hand, when the detected current value is larger than the current instruction value, both the transistors 161, 162 are turned off only for a period of time corresponding to the pulse-width time Tp2 only once during the control cycle Ts as shown in Fig. 4. Thus, the electromagnet current iL during this period decreases toward a current value iLmin (not shown) that can be regenerated from the negative pole 171b to positive pole 171a through the diodes 165, 166.

[0045] And in the both cases, after elapse of the pulse-width times Tp1, Tp2, either one of the transistors 161, 162 is turned on. Thus, during this period, the flywheel current is held in the amplifier circuit 150.

[0046] In the aforementioned turbomolecular pump 1, one housing is constituted by combining mainly the outer cylinder 127, the base portion 129 and the like, for example. The other elements of the pump main body 100 are accommodated in this housing. Note that, in the following explanation, in the constitution of the aforementioned pump main body 100, the rotor blade 102, the cylinder portion 102d, the metal disc 111, and the rotor shaft 113 are called collectively as the rotating body 103 in some cases. The rotating body 103 roughly includes the metal disc 111 and the rotor shaft 113. Moreover, in the constitution of the aforementioned pump main body 100, the upper-side radial-direction electromagnet 104, the lower-side radial-direction electromagnet 105, the axial-direction electromagnets 106A, 106B, the upper-side radial- direction sensor 107, the lower-side radial-direction sensor 108, and the axial-direction sensor 109 are called collectively as a magnetic bearing portion 110 in some cases. Moreover, the upper-side radial-direction sensor 107, the lower-side radial-direction sensor 108, and the axial- direction sensor 109 are called collectively as displacement sensors 107, 108, 109 in some cases. The magnetic bearing portion 110 roughly includes the electromagnets 104, 105, 106A, 106B and the displacement sensors 107, 108, 109. The magnetic bearing portion 110 is configured to enable levitation and / or dynamic stabilization of the rotating body 103 by magnetic attracting force or repulsion force without mechanical contact.

[0047] Fig. 5 is an example of a hardware configuration of the control device 200 according to the Embodiment. The control device 200 is an element which controls drive of the turbomolecular pump 1. The control device 200 is configured by the amplifier circuit 150 as described above and a microcomputer (Micro Controller Unit: MCU) including the aforementioned DSP portion as main bodies, for example. The control device 200 is electrically connected to the pump main body 100 via a connection cable 210. Note that, a male connector is provided in the pump main body 100, and a female connector in the control device 200, respectively, for example, and a female or male connector connectable to the male or female connector is provided on both ends of the connection cable 210. In the turbomolecular pump 1 of the same model, shapes of the respective connectors are unified.

[0048] The control device 200 can optionally include a processor 203 such as a central processing unit (CPU) which executes digital signalprocessing, various programs and the like, a main storage device 201 such as a ROM (read only memory) which stores a program executed by the CPU, a RAM (random access memory) used as a working area in which the program is extended and the like, an auxiliary storage device 202 such as a flash memory, EEP-ROM (Electrically Erasable Programmable Read-Only Memory) and the like, an input / output portion 206 which exchanges various types of information with the pump main body 100, external equipment such as a PC, an input device 204 such as an operation button, and an output device 205 such as a monitor, a display and the like.

[0049] Note that the input / output portion 206 may include a communication control function such as a network card, a wireless communication module, a mobile communication module and the like. Moreover, the control device 200 can further include a clock function not particularly mentioned, a temperature sensor and the like by a thermistor or the like.

[0050] The main storage device 201 stores various programs, applications and the like (software module), and each of functional elements of the entire system is realized by the processor 203 which executes these programs and applications. Note that, each module may be implemented by the programs and the applications independent from each other or may be implemented in a form of a subprogram, functions and the like, which are some of one integrated program or application. Moreover, each of these modules may be implemented as hardware by employing an integrated circuit (hardware module) or the like.

[0051] In this description, it is described that each of the modules is an entity (subject) which executes processing but in actuality, the processing is executed by the processor 203 which executes the program, the application and the like for realizing each of the modules.

[0052] The auxiliary storage device 202 stores various databases (DB). The "database" is a data collection organized and collected so that an optional data operation (extraction, addition, deletion, overwriting and the like, for example) from the processor or an external computer can be functionalstores one or a data collections. The database may be provided in the same housing as the processor 203 in a state connectable with the processor 203 and the likeor may be provided independently in a housing different from that of the processor 203.

[0053] The main storage device 201 stores programs such as a tuning module 211, a pump-drive module 212, a current-detection module 213, a position-detection module 214, a rotation-number detection module 215, a stationary-levitated detection module 216, an amplifier control module 217, a compensation module 218 and the like. Each of the functional elements of the control device 200 is realized by the processor 203 which executes these programs stored in the main storage device 201.

[0054] In the auxiliary storage device 202, standard information required for the operation of the control device 200 is stored. In the auxiliary storage device 202, information for determining whether the rotating body 103 is in a stationary-levitated state or not, that is, information related to reference ranges of the rotation number of the rotating body 103, the position of the rotating body 103, and the current flowing through the electromagnet wiring 151 is stored, for example. Moreover, in the auxiliary storage device 202, operation control information for operating the turbomolecular pump 1, that is, information related to the reference ranges of the rotation number of the rotating body 103 and the current flowing through the electromagnet wiring 151 is stored, for example. The information related to the reference ranges is standard target values on the rotation number of the rotating body 103, the position of the rotating body 103, the current flowing through the electromagnet wiring 151 and the like, specified for each model of the pump main body 100 for the determination of the stationary-levitated state and the operation of the turbomolecular pump.

[0055] These pieces of information may be prepared as plural combinations for each model information specifying the model of the turbomolecular pump 1. In Fig. 5, these pieces of information are expressed as turbomolecular-pump operation information 221. Note that the model information specifying the model of the turbomolecular pump 1 corresponds to a resistance value of an ID resistor 117 (see Fig. 6) different for each of the models provided in the pump main body 100, for example.

[0056] Each of the functional elements of the control device 200 will be explained in brief.The pump-drive module 212 (see Fig. 5) comprehensively controls basic operations of the turbomolecular pump 1. The pump-drive module 212 controls the drive of the turbomolecular pump 1 by cooperating with the current-detection module 213, the position-detection module 214, the rotation-number detection module 215, the stationary-levitated detection module 216, the compensation module 218, the amplifier control module 217 and the like, for example. The pump-drive module 212 operates the pump main body 100 by bringing the rotating body 103 to the stationary- levitated state and by rotating the rotating body 103, for example.

[0057] The tuning module 211 makes adjustment (so-called tuning) of transmission functions for keeping the rotating body 103 in a desired operation state. The tuning module 211 is typically an element for performing tuning related to the position of the rotating body 103 of the turbomolecular pump 1. The tuning module 211 adjusts the positions of the rotor shaft 113 and the metal disc 111 in the rotating body 103 with respect to the magnetic bearing portion 110 by cooperating with the pump- drive module 212, the current-detection module 213, the position- detection module 214, the stationary-levitated detection module 216, the compensation module 218, the amplifier control module 217 and the like, for example. Note that the tuning module 211 is configured not to execute tuning of a matter related to those other than the position of the rotating body 103 of the turbomolecular pump 1.

[0058] The current-detection module 213 detects a state of the power source of the turbomolecular pump 1. In this Embodiment, the current- detection module 213 detects an ON state and an OFF state of the power source of the control device 200, for example. Moreover, the current- detection module 213 is connected to the current detection circuit 181 of the amplifier circuit 150 and detects a current amount flowing through the electromagnet wiring 151 of the electromagnets 104, 105, 106A, 106B and the like, for example.

[0059] The position-detection module 214 detects the position of the rotating body 103. The position-detection module 214 is connected to displacement sensors 107, 108, 109 and detects the position of the rotating body 103 with respect to the magnetic bearing portion 110, for example. The rotation-number detection module 215 detects the rotation number of the rotating body 103. The rotation-number detection module 215 isconnected to the rotation-speed sensor 115 and detects the rotation number of the rotating body 103, for example.

[0060] The stationary-levitated detection module 216 is an element which determines whether the rotating body 103 is in the stationary- levitated state or not. The stationary-levitated detection module 216 determines whether the rotating body 103 is in a predetermined stationary-levitated state or not on the basis of the position signal detected by the displacement sensors 107, 108, 109 and a rotation-speed signal detected by the rotation-speed sensor 115, for example.

[0061] The amplifier control module 217 is an element which amplifies various types of electric signals in an electric circuit. Functions of the amplifier control module 217 can be realized by an analog circuit, a digital circuit or a combination of an analog circuit and a digital circuit. The amplifier control circuit 191 having the PWM control function shown in Fig. 2 is an example of means for realizing the function of the amplifier control module 217 of this Embodiment. The amplifier control module 217 can increase, decrease or maintain the electromagnet current iL by switching between the ON state and the OFF state of the transistors 161, 162 of the amplifier circuit 150, for example.

[0062] The compensation module 218 is an element which corrects a signal in an electric circuit. Functions of the compensation module 218 can be realized by an analog circuit, a digital circuit or a combination of an analog circuit and a digital circuit. The aforementioned compensation circuit is an example of means for realizing the function of the compensation module 218 of this Embodiment. The compensation module 218 can operate so as to keep a shift of the rotating body 103 based on a position signal of the rotating body 103 detected by the displacement sensors 107, 108, 109 within a predetermined range, for example. Moreover, the compensation module 218 can operate so as to keep a shift in various types of sensor signals by an environmental temperature detected by a temperature sensor, not shown, in a predetermined range, for example.

[0063] <Operation of Turbomolecular Pump> First, an outline of an operating method for the turbomolecular pump 1 will be explained and then, the tuning control by the control device 200 will be explained. Fig. 7 is a flow chart of the entire operation ofthe turbomolecular pump 1 according to the Embodiment. The pump-drive module 212 of the control device 200 executes the following processing by cooperating with the other modules as necessary.

[0064] The control device 200 is brought into the ON state when an operation of Power ON is received by a user, an external device or the like (Step S710), for example. Then, when the pump-drive module 212 obtains an instruction signal to start an operation (Yes at Step S715), it starts magnetic levitation of the rotating body 103 by the magnetic bearing portion 110 (Step S720). Note that the pump-drive module 212 may be configured to be brought into the OFF state (Step S770) when the instruction signal to start the operation is not obtained in a predetermined period (No at Step S715), when an instruction signal of Power OFF is received, or some error signal is obtained or the like, for example. Moreover, the pump-drive module 212 may be configured to omit the step S715 and to start the magnetic levitation (Step S720) as it is, when the ON state is brought about (Step S710), for example. The instruction signal to start the operation or the like may be an input from the user, the external device or the like or may be generated by execution by the processor 203 of an operation program of the turbomolecular pump 1. Hereinafter, the same applies to the instruction signals for which a transmission source is not particularly specified.

[0065] When the magnetic levitation is started, the tuning module 211 performs the tuning step (Step S730). The tuning step will be described later.

[0066] After the tuning step, the pump-drive module 212 starts sucking by rotating the rotating body 103 (Step S740), when an instruction signal to start rotation of the rotating body 103 is received (Yes at Step S735), for example. The pump-drive module 212 rotates / drives the rotation of the rotor shaft 113 by electrically controlling an operation state of the motor 121. And the pump-drive module 212 continues the rotation of the rotating body 103 until the instruction signal to end the rotation of the rotating body 103 is received (No at Step S745), and when the instruction signal to end the rotation is received (Yes at Step S745), it ends the rotation of the rotating body 103 and ends the sucking (Step S750), for example. Note that the pump-drive module 212 may be configured to end the magnetic levitation (Step S760), when the instruction signal to start the rotation is not obtained during a predetermined period (Noat Step S735), when the instruction signal to end the magnetic levitation is received, when some error signal is obtained or the like, for example. Moreover, the pump-drive module 212 may be configured to end the rotation (Step S750), when predetermined rotation operation time has elapsed, some error signal is obtained or the like, for example, at Step S745.

[0067] When the instruction signal of re-rotation is received after the end of the rotation (Yes at Step S755), the processing returns to Step S730, and the tuning module 211 executes the tuning control flow (stationary-levitated) 900. On the other hand, when the instruction signal of re-rotation is not received (No at Step S755), the pump-drive module 212 ends the magnetic levitation of the rotating body 103 (Step S760). Note that the pump-drive module 212 may be configured to end the magnetic flowing (Step S760) when the instruction signal of re-rotation is not obtained during a predetermined period, when the instruction signal to end the magnetic levitation is received or some error signal is obtained or the like.

[0068] When the instruction signal of the re-operation is received after the end of the magnetic levitation (Yes at Step S765), the pump- drive module 212 returns to Step S720. And when the instruction signal of the re-operation is not received (No at Step S765), the pump-drive module 212 brings the power source to the OFF state (Step S770). The pump-drive module 212 may be configured to bring the power source to the OFF state when the instruction signal of the re-operation is not obtained during a predetermined period, when the instruction signal to bring the power source to the OFF state is received, some error signal is obtained or the like, for example.

[0069] Here, in the turbomolecular pump 1, in general, the levitation control parameter for magnetic levitation can be different for each combination of the models of the pump main body 100 and the models of the control device 200. For example, specifically, in the pump main body 100 and the control device 200, differences can be generated in the levitation control parameter for each combination even within design tolerances of component dimensions, assembling accuracy and the like due to variations thereof. Thus, in an electronic circuit portion of the conventional pump main body 100, model information for specifying the model (type) of the pump main body 100, individual identification information (serial numbers, for example) for identifying individuals ofthe pump main body 100, and information related to the levitation control parameters specific to the combination with the control device 200, for example, are stored.

[0070] The levitation control parameter information is information with which the control device 200 causes the pump main body 100 to operate and control parameters (specifically, control gains, sensor offsets and the like of the magnetic bearing portion 110, for example) used when the drive of the magnetic bearing portion 110 is controlled with the purpose of magnetically levitating the rotating body 103 or rotating the rotating body 103, for example. This levitation control parameter information is typically stored at initial setting of the turbomolecular pump 1 in the electronic circuit portion 141 after adjustment for each combination of the specific pump main body 100 and the control device 200.

[0071] On the other hand, a user owning a plurality of the turbomolecular pumps 1 might have an idea to reassemble and connect the pump main body 100 with the control device 200 of a different combination for operation in the case of defective operation or the like of a certain pump main body 100 or control device 200, for example. In such a case, the levitation control parameter information stored in the pump main body 100 is optimized in the combination with the original control device 200 and might not be suitable for the combination with the control device 200 after the re-assembling in some cases. If the turbomolecular pump 1 is operated by using the levitation control parameter, which is not optimal, the rotating body 103 might vibrate during the operation, the magnetic bearing portion 110 might contact the protective bearing 120 or the like, and there is a concern that the turbomolecular pump 1 is broken.

[0072] <Tuning> In the electronic circuit portion 141 of the pump main body 100 in this Embodiment, the individual identification information for identifying the individuals of the pump main body 100 and the information related to the levitation control parameter are not stored. And the tuning module 211 of this Embodiment performs the following tuning step, for example, in order to deal with the case where the combination of the pump main body 100 and the control device 200 is changed.

[0073] That is, the tuning module 211 performs the tuning of the magnetic bearing portion 110 at least either one of (A) a case where thecurrent-detection module 213 detects that the power source of the turbomolecular pump 1 was switched from OFF to ON; and (B) a case where the stationary-levitated detection module 216 detects that the rotating body 103 is in the stationary-levitated state.

[0074] In the following, specific examples of the tuning methods (A) and (B) of the magnetic bearing portion 110 by the tuning module 211 will be shown, and the operation of the tuning module 211 will be explained. The tuning module 211 performs the tuning of the magnetic bearing portion 110 correspondingly to the operation of the pump-drive module 212 shown in Fig. 7, for example (Step S730).

[0075] <A. Tuning Based on Power ON> Fig. 8 is a tuning control flow (power ON) 800 according to the Embodiment. In a start state of the tuning control flow 800, a tuning request flag is OFF. The tuning module 211 of the control device 200 executes the tuning control flow 800, when the power source in Fig. 7 is brought into the ON state (Step S710). That is, the tuning module 211 changes the tuning request flag to ON (Step S820), when the current-detection module 213 detects that the power source of the turbomolecular pump 1 was switched from OFF to ON (Yes at Step S810). When the current-detection module 213 does not detect that the power source was switched from OFF to ON (No at Step S810), the tuning module 211 does not turn ON the tuning request flag but keeps it OFF.

[0076] Fig. 9 is a tuning control flow (stationary-levitated) 900 according to the Embodiment. The tuning module 211 repeatedly executes the tuning control flow 900. That is, the tuning module 211 evaluates whether the rotating body 103 is in the stationary-levitated state or not (Step S910). The tuning module 211 evaluates whether the rotating body 103 is in the stationary- levitated state or not on the basis of determination by the stationary- levitated detection module 216, which will be described later, for example.

[0077] Then, when the rotating body 103 is in the stationary-levitated state (Yes at Step S910), the tuning module 211 determines whether the tuning request flag is ON or not (Step S920). When the tuning request flag is ON (Yes at Step S920), the tuning module 211 performs the tuning of the magnetic bearing portion 110, which will be described later (StepS930). When the tuning of the magnetic bearing portion 110 is ended, the tuning module 211 changes the tuning request flag to OFF (Step S940) and ends the tuning control flow 900.

[0078] On the other hand, when the rotating body 103 is not in the stationary-levitated state (No at Step S910), the tuning module 211 repeatedly performs the step S910. Moreover, when the tuning request flag is not ON (No at Step S920), the tuning module 211 ends the tuning control flow 900. Note that the tuning module 211 may be configured to repeatedly execute the tuning control flow 900 all the time or may be configured to repeatedly execute it, if a predetermined execution condition is satisfied (when the motor 121 is not driven, for example).

[0079] Fig. 10 is a stationary-levitated state determination flow according to the Embodiment. The stationary-levitated detection module 216 determines whether the rotating body 103 is in the stationary-levitated state or not by executing the following processing. That is, the stationary-levitated detection module 216 determines whether some error (an emergency stop signal by an external input, for example) has been detected in the turbomolecular pump 1 (Step S1010). If no error has been detected (Yes at Step S1010), the stationary-levitated detection module 216 determines whether the rotation number detected by the rotation-number detection module 215 is within a reference range or not (Step S1020). The reference range related to the rotation number can be approximately 1 Hz or less or the like at which it can be considered that the rotating body 103 is stationary, for example.

[0080] When the rotation number is within the reference range (Yes at Step S1020), the stationary-levitated detection module 216 determines whether a position of the rotating body 103 with respect to the magnetic bearing portion 110 detected by the position-detection module 214 is within a reference range or not (Step S1030). The reference range relatedto the position of the rotating body 103 can be set to ± m or the likewith respect to the reference position (target levitation position) of the applicable type of the rotating body 103 of the pump main body 100, for example. When the position of the rotating body 103 is within the reference range (Yes at Step S1030), the stationary-levitated detection module 216 determines whether the current flowing through the electromagnet wiring 151 detected by the current-detection module 213 iswithin the reference range or not (Step S1040). The reference range related to the current of the electromagnet wiring 151 can be set to a range from 0.2A to 1.0A or the like, for example.

[0081] When the current is within the reference range (Yes at Step S1040), the stationary-levitated detection module 216 determines that the rotating body 103 is in the stationary-levitated state (Step S1050). And in the case of No at Steps S1010 to 1040, the stationary-levitated detection module 216 determines that the rotating body 103 is not in the stationary-levitated state (Step S1060). Note that the stationary- levitated detection module 216 can execute Steps S1010 to 1040 in random order.

[0082] The tuning of the magnetic bearing portion 110 performed by the tuning module 211 will be explained. The tuning module 211 adjusts (corrects) a magnetic-bearing control gain and offsets of the displacement sensors 107, 108, 109 as levitation control parameters. The tuning module 211 adjusts the control parameter by performing characteristic confirmation by step response and an excitation test, for example. The tuning module 211 more preferably adjusts only the offsets of the displacement sensors 107, 108, 109 as the levitation control parameters. When only the offsets of the displacement sensors 107, 108, 109 are adjusted, time required for the tuning can be shortened, and critical adjustment can be made, which is preferable.

[0083] <Offset of Displacement Sensor> The tuning module 211 excites the rotating body 103 in each of the upper-side radial direction, the lower-side radial direction, and the axial direction. The tuning module 211 displaces the rotating body 103 in one and the other in each direction so that it hits the protective bearing 120. The tuning module 211 sets a center of displacement position when the protective bearing 120 is hit on one and the other, for example, as offsets (zero points) of the displacement sensors 107, 108, 109 on the basis of detection results of vibration response (displacement signals) at this time. By adjusting the position of the rotating body 103 to thecenter 113) ofthe rotating body 103 can be matched with a center of a clearance of the protective bearing 120, for example. Note that it may be so configured that the tuning module 211 detects a levitation position where adifference in integration outputs, which is a difference in control currents flowing through opposed electromagnets, becomes zero as a magnetic center and use this as offsets of the displacement sensors 107, 108, 109. The tuning module 211 stores the obtained offsets of the displacement sensors 107, 108, 109 as turbomolecular-pump operation information in the auxiliary storage device 202, for example.

[0084] <Setting of Magnetic-bearing Control Gain> The magnetic-bearing control gain can be set by using the step response and a limit sensitivity method, for example. The tuning module 211 evaluates response characteristics when the magnetic-bearing control gain is applied by gradually increasing a small value to a large value in a stepped manner, and when the vibration of a response signal satisfies a predetermined end condition, the control gain is set on the basis of the gain at that time, for example. The tuning module 211 sets a gain smaller than the gain at the end condition only by a predetermined amount as the control gain, for example. Alternatively, the tuning module 211 gradually increases the magnetic-bearing control gain, obtains a limit gain and a limit cycle satisfying a predetermined lasting vibration condition, for example, and can adjust the control device 200 on the basis of the gain whose amplitude attenuates to 1 / 4 and the response cycle at that time. The tuning module 211 stores the obtained magnetic-bearing control gain as the turbomolecular operation information in the auxiliary storage device 202, for example.

[0085] <B. Tuning Based on Stationary-levitated> Fig. 11 is a tuning control flow (stationary-levitated) 1100 according to the Embodiment. When the tuning is performed on the basis of the stationary-levitated, the tuning module 211 repeatedly executes the tuning control flow 1100. The tuning control flow 1100 is in common with the tuning control flow 900 except that Step S1150, which will be described later, is different. In a start state of the tuning control flow 1100, the tuning request flag is OFF.

[0086] That is, the tuning module 211 evaluates whether the rotating body 103 is in the stationary-levitated state or not (Step S1110). The tuning module 211 evaluates whether the rotating body 103 is in the stationary-levitated state or not on the basis of the determination by the aforementioned stationary-levitated detection module 216, for example.

[0087] Then, when the rotating body 103 is in the stationary-levitated state (Yes at Step S1110), the tuning module 211 determines whether the tuning request flag is ON or not (Step S1120). When the tuning request flag is ON (Yes at Step S1120), the tuning module 211 performs the tuning of the aforementioned magnetic bearing portion 110 (Step S1130). When the tuning of the magnetic bearing portion 110 is finished, the tuning module 211 changes the tuning request flag to OFF (Step S1140) and ends the tuning control flow 1100.

[0088] On the other hand, when the rotating body 103 is not in the stationary-levitated state at Step S1110 (No at Step S1110), the tuning module 211 changes the tuning request flag to ON (Step S1150) and returns to Step S1110. Moreover, when the tuning request flag is not ON (No at Step S1120) at Step S1120, the tuning module 211 ends the tuning control flow 1100. Note that the tuning module 211 may be configured to repeatedly execute the tuning control flow 1100 all the time or may be configured to repeatedly execute it when a predetermined execution condition is satisfied (when the motor 121 is not driven, for example).

[0089] <Working Effects> In the aforementioned configuration, the turbomolecular pump 1 (one example of the magnetic bearing device) includes the rotating body 103, the magnetic bearing portion 110 which levitates the rotating body 103 into the air and supports it by the magnetic force, and the control device 200 (one example of the control portion, a control unit) which controls the drive of the magnetic bearing portion 110. The control device 200 includes the tuning module 211 (one example of the tuning portion) which performs tuning of the magnetic bearing portion 110, the current-detection module 213 (one example of the power-source detecting portion) which detects a state of the power source of the turbomolecular pump 1, and the stationary-levitated detection module 216 (one example of a stationary-levitated detecting portion) which detects whether the rotating body 103 is in the stationary-levitated state or not. Then, the tuning module 211 is configured to execute the tuning of the magnetic case where thesourceturbomolecular pump 1 was switched from OFF to ON and (B) a case where the stationary-levitated detection module 216 detects that the rotating body 103 is in the stationary-levitated state.

[0090] As a result, at least each time the power source is changed from the OFF state to the ON state, the tuning can be performed. As a result, even if the pump main body 100 is changed while the power source is in the OFF state, for example, the tuning is performed without fail and thus, the turbomolecular pump 1 can be operated in the state where the levitation control parameter is optimized. Accordingly, the rotating body 103 can be levitated / supported by the magnetic bearing portion 110 at an appropriate position with respect to the radial direction and the axial direction, the turbomolecular pump 1 can be operated stably, and occurrence of damage or the like can be avoided.

[0091] Moreover, by performing the tuning by the tuning module 211 each time the stationary-levitated detection module 216 detects the stationary-levitated state, the tuning is performed each time the sucking by the turbomolecular pump 1 is stopped. As a result, the operation can be performed by maintaining the levitation control parameter in the optimal state each time, even in the case where the operation of the turbomolecular pump 1 takes a long time such as the case where the rotating body 103 is rotated again after the end of the rotation or where the stationary-levitated state is brought about again after the stationary-levitated state is ended or the like.

[0092] A timing when the tuning module 211 performs the tuning may be either one of the aforementioned (A) and the aforementioned (B). Moreover, as shown in the aforementioned configuration, the tuning module 211 may be configured to perform the tuning of the magnetic bearing portion 110 (A) when the current-detection module 213 detects that the power source of the turbomolecular pump 1 was switched from OFF to ON, and (B) when the stationary-levitated detection module 216 detects that the rotating body 103 is in the stationary-levitated state. As a result, the turbomolecular pump 1 can be operated in a state where the levitation control parameter is optimized in preparation for the case where the pump main body 100 is changed.

[0093] Note that, in the aforementioned configuration, theturbomolecular 1 includes theexample of apump unit) having the rotor blade 102 for exhausting the gas to at least a part of the rotating body 103 and the control device 200 (one example of the control unit including the control portion). That is, theturbomolecular pump 1 can be grasped as an example of the magnetic bearing device according to this art.

[0094] Moreover, in the aforementioned configuration, the tuning module 211 is configured to perform the tuning of the magnetic bearing portion 110 when the rotation-number detection module 215 (one example of the rotation detecting portion) detects that the rotating body 103 is changed from a rotating state to a non-rotating state and when the stationary-levitated detection module 216 detects that the rotating body 103 is in the stationary-levitated state. As a result, it can be reliably confirmed that the rotating body 103 is in the stationary-levitated sate, and safe and accurate tuning can be performed in a state there is no influence such as vibration by the rotation.

[0095] Moreover, in the aforementioned configuration, the tuning module 211 is configured to adjust the rotation reference position of the rotating body 103 on the basis of the information related to the position of the rotating body 103 with respect to the protective bearing 120 (one example of a peripheral component) disposed in the periphery of the rotating body 103 as the tuning. As a result, even if the pump main body 100 is changed, the levitation control parameter can be adjusted so as to correspond to variation of an individual of the pump main body 100 by simple processing in a relatively short time. As a result, the stationary-levitated state of the turbomolecular pump 1 can be stably realized, and vibration characteristics within an operation frequency range can be suitably suppressed.

[0096] In the aforementioned configuration, the tuning module 211 is configured capable of performing the tuning without obtaining the levitation control parameter from the pump main body 100. As a result, the pump main body 100 can be realized as the one not including the electronic circuit portion 141 (one example of the storage portion) in which the levitation control parameter (one example of the control information) for causing the pump main body 100 to operate is stored.

[0097] Moreover, in the aforementioned configuration, the tuning module 211 is configured capable of performing the tuning without obtaining the individual identification information for identifying the individuals from the pump main body 100. As a result, the pump main body 100 can be realized as the one not including the storage portion storing the individual identification information for identifying the individualsof the pump main body 100. Accordingly, those skilled in the art can understand that the pump main body 100 can be realized as the one not including the electronic circuit portion 141 itself such as an EEP-ROM and the like. As described above, the pump main body 100 can be configured not to include the storage portion in the electronic circuit portion 141 or not to include the electronic circuit portion 141. By employing the configuration as above, cost reduction of the turbomolecular pump 1 (pump main body 100) can be promoted.

[0098] Note that, even if the levitation control parameter is stored in the electronic circuit portion 141 of the pump main body 100, the tuning module 211 is configured to set the magnetic-levitation control parameter without being influenced by this levitation control parameter. For example, even if the levitation control parameter is stored in advance in the electronic circuit portion 141 of the pump main body 100, the tuning module 211 may be configured to set the magnetic-levitation control parameter without reading the levitation control parameter stored in advance. Alternatively, even if the levitation control parameter is stored in advance in the electronic circuit portion 141 of the pump main body 100, and this levitation control parameter stored in advance is read out, the tuning module 211 may be configured to newly set the magnetic levitation control parameter based on the aforementioned configuration without being influenced by this levitation control parameter stored in advance. Accordingly, the control device 200 with the aforementioned configuration can operate the turbomolecular pump 1 in a state where the levitation control parameter is optimized by appropriately performing the tuning regardless of presence / absence of the electronic circuit portion 141 or stored information thereof.

[0099] [Embodiment 2] <Configuration of Turbomolecular Pump> A turbomolecular pump 1A according to an Embodiment 2 will be explained with reference to Fig. 12 to Fig. 15. Fig. 12 is an example of a vertical sectional view of the turbomolecular pump 1A according to the Embodiment 2. Fig. 13 is an example of a hardware configuration of the control device 200 according to the Embodiment 2. Fig. 14 is a block diagram showing an example of a circuit constituting a disassembly detecting portion of the turbomolecular pump. Fig. 15 is a tuning control flow (Power ON) according to the Embodiment 2.

[0100] The turbomolecular pump 1A of the Embodiment 2 is different from the Embodiment 1 in points that the pump main body 100 and the control device 200 are integrally connected by a mechanical connecting portion 231 and an electric connecting portion 232, and a disassembly detecting portion 235 is further provided in the vicinity of the connecting portion with the mechanical connecting portion 231 of the control device 200, and a connection detection module 219 in the main storage device 201 of the control device 200. The configurations other than them may be similar to those in the Embodiment 1, and explanation for the similar configurations, actions and effects will be omitted.

[0101] As shown in Fig. 12, the housing of the pump main body 100 and the housing of the control device 200 are integrally fixed by the mechanical connecting portion 231 mechanically. Then, the electronic circuit portion 141 of the pump main body 100 and the amplifier circuit 150 of the control device 200 are electrically connected by an electric wiring 210A, not shown, extending through the electric connecting portion 232. The electric wiring 210A includes connectors on both ends and is configured such that the connector on one end is connected to a socket portion provided in the electronic circuit portion 141 of the pump main body 100, and the connector on the other end is connected to the socket portion provided in the amplifier circuit 150 of the control device 200.

[0102] As shown in Fig. 14, the disassembly detecting portion 235 includes a disassembly detection switch 235S, a disassembly-information storage portion 235M, and a power source portion 235V for holding a voltage of the disassembly-information storage portion 235M. The disassembly detection switch 235S is a switch which is installed and operated such that it is brought into a state where a circuit is open when the control device 200 and the pump main body 100 are separately removed (disconnected), while into a state where the circuit is closed when the control device 200 and the pump main body 100 are integrally assembled. The disassembly detection switch 235S can be constituted by a self-return contact or the like such as a push button switch, for example. In the disassembly-information storage portion 235M, information indicating that the control device 200 and the pump main body 100 are not removed (not disassembled) is stored. The disassembly-information storage portion 235M can be constituted by a storage device such as an SRAM (Static Random Access Memory) or the like, for example. In thedisassembly detecting portion 235 with the configuration as above, it is so configured that, when the contact of the disassembly detection switch 235S is opened, the voltage of the disassembly-information storage portion 235M is not maintained, and the information stored in the disassembly-information storage portion 235M and indicating that disassembly has not been performed is erased.

[0103] The connection detection module 219 is configured to detect whether the connection between the pump main body 100 including the rotating body 103 as well as the magnetic bearing portion 110 and the control device 200 has been released or not. The connection detection module 219 is electrically connected to the disassembly-information storage portion 235M of the disassembly detecting portion 235, for example. And when the information indicating that disassembly has not performed is stored in the disassembly-information storage portion 235M, the connection detection module 219 determines that the connection between the pump main body 100 and the control device 200 has not been released. Moreover, when the information indicating that the disassembly has not been performed is not stored in the disassembly-information storage portion 235M, the connection detection module 219 determines that the connection between the pump main body 100 and the control device 200 has been released.

[0104] <Operation of Turbomolecular Pump> In the turbomolecular pump 1A as above, the tuning module 211 executes the tuning control flow 1500 shown in Fig. 15, when the power is brought into the ON state in Fig. 7 (Step S710). That is, when the current-detection module 213 detects that the power source of the turbomolecular pump 1 has been switched from OFF to ON (Yes at Step S1510), the tuning module 211 evaluates whether the connection detection module 219 detects the disconnection between the pump main body 100 and the control device 200 (Step S1520).

[0105] When the connection detection module 219 detects the disconnection (Yes at Step S1520), the tuning module 211 changes the tuning request flag to ON (Step S1520). When the connection detection module 219 does not detect the disconnection (No at Step S1520), the tuning module 211 does not turn the tuning request flag ON but keeps it OFF. After that, the tuning module 211 operates similarly to that in the Embodiment 1. That is, when the pump-drive module 212 starts the magneticlevitation (Step S720), the tuning control flow 900 is executed. Note that, after the tuning control flow 900 is executed, the tuning module 211 causes the information indicating that the disassembly has not been performed to be stored in the disassembly-information storage portion 235M.

[0106] <Working Effects> In the aforementioned configuration, the control device 200 (one example of the control portion) includes the connection detection module 219 configured to detect whether the magnetic bearing portion 110 and the control device 200 have been disconnected or not. The tuning module 211 is configured to perform the tuning, when the current-detection module 213 detects that the power source was brought into the ON state, and when the connection detection module 219 (one example of the connection detecting portion) detects the disconnection between the magnetic bearing portion 110 and the control device 200 (one example of the control portion). As a result, when the pump main body 100 was changed with respect to the control device 200, for example, the turbomolecular pump 1 can be operated in the state where the levitation control parameter is optimized without fail.

[0107] Note that, in the other viewpoints, a person ordinarily skilled in the art can understand that the control device 200 may include only the configuration of performing, with the tuning module 211, the tuning (C) when the connection detection module 219 detects the disconnection between the pump main body 100 and the control device 200.

[0108] <Variation> In the aforementioned configuration, the disassembly detecting portion 235 is disposed in the vicinity of the mechanical connecting portion 231 and is configured to detect the disassembly between the pump main body 100 and the control device 200. However, the form of the disassembly detecting portion 235 is not limited to that. For example, the disassembly detecting portion 235 may be provided in relation with the electric wiring 210A. The disassembly detection switch 235S may be provided in the control-device side connector of the electric wiring 210A which electrically connects the DSP portion of the control device 200 and the electromagnets 104, 105, 106A, 106B (electromagnet wiring 151) of the pump main body 100, for example. The disassembly detection switch 235S is a self-return contact such as a push-in switch or the like provided inthe connector portion (a plug, for example) on the control device side, for example, and is configured to be inserted into the connector portion (socket) on the pump main body 100 side and to be pressed when a predetermined connection position is reached so that the contact is closed. Moreover, the disassembly detection switch 235S is configured such that, when the connector portion (plug) on the control device 200 side is separated from the connector portion (socket) on the pump main body 100 side, the contact is opened. By means of the configuration as above, too, the disassembly between the pump main body 100 and the control device 200 can be detected similarly to the Embodiment 2.

[0109] Note that the present invention is not limited to the aforementioned Embodiments but includes various variations. For example, the aforementioned Embodiments are explained in detail in order to explain the present invention to be easily understood and are not necessarily limited to those including all the configurations which have been explained. Moreover, a part of the configuration of one Embodiment can be replaced with the configuration of another configuration, or the configuration of the other Embodiments can be added to the configuration of the one Embodiment and combined. Furthermore, regarding a part of the configuration of each Embodiment, addition / deletion / replacement of the other configurations is possible. Note that the aforementioned Embodiments disclose the configuration described at least in the scope of claims.

[0110] 1 Turbomolecular pump 100 Pump main body 103 Rotating body 104 Upper-side radial-direction electromagnet 105 Lower-side radial-direction electromagnet 106A, 106BAxial-direction electromagnet 107 Upper-side radial-direction sensor 108 Lower-side radial-direction sensor 109 115211 Tuning module 212 Pump-drive module 213 Current-detection modulePosition-detection module Rotation-number detection module Stationary-levitated detection module Amplifier control moduleCompensation module

Claims

CLAIMS

1. A device comprising: a rotating body; a magnetic bearing portion which levitates and supports the rotating body by a magnetic force; and a control portion which controls drive of the magnetic bearing ortion, wherein the control portion includes: a tuning portion which tunes the magnetic bearing portion; a power-source detecting portion which detects a state of a power ource of the device; and a stationary-levitated detecting portion which detects whether the otating body is in a stationary-levitated state or not, and the tuning portion is configured such that the tuning of the agnetic bearing portion is performed at least in either one of (A) a case where the power-source detecting portion detects that a ower source of the device has been switched from OFF to ON; and (B) a case where the stationary-levitated detecting portion detects hat the rotating body is in the stationary-levitated state. Claim 2] The device according to claim 1, wherein the control portion includes a rotation detecting portion which etects whether the rotating body is rotating or not, the tuning portion is configured to perform tuning of the magnetic earing portion when the rotation detecting portion detects that the otating body has been brought into a non-rotating state from a rotating tate, and the stationary-levitated detecting portion detects that the otating body is in the stationary-levitated state. Claim 3] The device according to claim 1, wherein the tuning portion is configured to perform tuning of the magneticthatpower source to ON, and (B) hen the stationary-levitated detecting portion detects that the rotating ody is in the stationary-levitated state.

4. The device according to claim 1, wherein the control portion includes a connection detecting portion configured to detect whether connection between the magnetic bearing portion and the control portion has been released or not, the tuning portion is configured to perform tuning of the magnetic bearing portion when the power-source detecting portion detects a state n which a power source of the device is ON, and (C) when the connection etecting portion detects that the connection between the magnetic earing portion and the control portion has been released. Claim 5] The device according to claim 1, wherein the tuning portion is configured to adjust a rotation reference osition of the rotating body on the basis of information related to a osition of the rotating body with respect to a peripheral component isposed in a periphery of the rotating body. Claim 6] The device according to any one of claims 1 to 5, in the form of a urbomolecular pump and comprising: a pump unit having a rotor blade for exhausting a gas to at least a art of the rotating body; and a control unit including the control portion. Claim 7] The device according to claim 6, further comprising: a wiring portion for connecting the pump unit and the control unit, herein the pump unit includes a pump-side connecting portion to which one nd of the wiring portion is connected, and the control unit includes a ontrol-side connecting portion to which the other end of the wiring ortion is connected. Claim 8] The device according to claim 6, wherein the pump unit does not include a portion in which control nformation for causing the pump unit to operate is stored. Claim 9] The device according to claim 8, whereinthe pump unit does not include a storage portion in which individual identification information for identifying individually the pump unit is stored.

10. A control method for a magnetic bearing portion which levitates a rotating body in air and supports the rotating body by a magnetic force, the method comprising: by using a control portion which controls drive of the magnetic earing portion, performing tuning of the magnetic bearing portion is performed at east in either one of: (A) a case where detection is made that a power source of a device ncluding the rotating body, the magnetic bearing portion, and the ontrol portion has been switched from OFF to ON; and (B) a case where detection is made that the rotating body is in a tationary-levitated state.

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