Vacuum pump

Abstract

To provide a vacuum pump that reduces the number of pins used for data transmission and has high extendability, the vacuum pump includes a pump main body (100) that sucks and exhausts gas; a plurality of physical sensors (21 to 23) provided in the pump main body; and a connector (10) used for connection with an external device (200). The vacuum pump further includes: a detection circuit (56) that detects detection data from an analog signal output from each of the plurality of physical sensors (21 to 23); a signal conversion circuit (54) that converts the detection data into digital detection data as a digital signal; and a serial communication bus (33) that performs data communication with the external device (200) via the connector (10). The serial communication bus (33) outputs a serial signal including the digital detection data.

Description

VACUUM PUMP[Technical Field]

[0001] The present invention relates to a vacuum pump.[Background Art]

[0002] In general, a vacuum pump typified by a turbo molecular pump or the like includes a pump main body that exhausts gas and a control device (external device) that controls the pump main body. Various physical sensors such as a thermistor for detecting temperature and a rotation sensor for detecting a rotation angle on the basis of a change in magnetism are attached to the pump main body, and the control device controls the pump main body in response to an output from the physical sensor.

[0003] For example, PTL 1 describes that an output from a physical sensor is subjected to parallel-serial conversion, and converted data is transmitted to a control device via a serial communication bus connecting a pump main body and the control device.[Citation List][Patent Literature]

[0004] [PTL 1] Japanese Patent Application Publication No. 2004-52727[Summary of Invention][Technical Problem]

[0005] In recent years, since a vacuum pump is provided with a large number of physical sensors, types of data transmitted from a pump main body to a control device are also increasing. In a case where the pump main body and the control device are connected by a parallel communication bus, the number of signal lines for data transmission also increases according to the number of physical sensors. As a result, the number of pins required for data transmission also increases in the connector connected to the parallel communication bus. Since the total number of pins of the connector is determined, there is a possibility that it is not possible to cope with an increase in the number of pins required for data transmission.

[0006] In addition, in PTL 1 , since the pump main body and the control device are connected by the serial communication bus, the number of pins required for datatransmission can be reduced. However, in PTL 1 , since a detection circuit that detects a measurement value such as a temperature and a rotation angle on the basis of an output of a physical sensor is provided on the control device side, when the number of physical sensors is increased, a detection circuit on the control device side also needs to be added, which reduces extendability.

[0007] Therefore, a main object of the present invention is to provide a vacuum pump that reduces the number of pins used for data transmission and has high extendability.[Solution to Problem]

[0008] In order to achieve the above object, a first aspect of the present invention provides a vacuum pump including: a pump main body that sucks and exhausts gas; a plurality of physical sensors provided in the pump main body; and a connector used for connection with an external device, in which the vacuum pump includes: a detection circuit that detects detection data from an analog signal output from each of the plurality of physical sensors; a signal conversion circuit that converts the detection data into digital detection data as a digital signal; and a serial communication bus that performs data communication with the external device via the connector, and the serial communication bus outputs a serial signal including the digital detection data.

[0009] Preferably, a first circuit board constituting the signal conversion circuit; and a second circuit board having an input port, to which the analog signal is input, and constituting the detection circuit, in which the first circuit board includes: an extension port that is connected to the second circuit board; and an output port that outputs the digital detection data.

[0010] Preferably, the detection circuit is provided according to a type of the analog signal output from each of the plurality of physical sensors.

[0011] Preferably, the first circuit board has a rectangular outer shape, the output port and the extension port are disposed on one side of the first circuit board, and the input port is disposed on another side of the first circuit board facing the one side.

[0012] Preferably, the number of physical sensors provided in the pump main body is larger than the number of data transmission pins used for transmission of the digital detection data, among pins of the connector used for connection with the serial communication bus.

[0013] Preferably, the connector includes a relay board that relays electrical connection with the external device, and the detection circuit and the signal conversion circuit perform data communication with the external device via the relay board.[Advantageous Effects of Invention]

[0014] According to the present invention, it is possible to provide a vacuum pump that reduces the number of pins used for data transmission and has high extendibility.Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.[Brief Description of Drawings]

[0015] Fig. 1 is a longitudinal cross-sectional view of a turbo molecular pump.Fig. 2 is a circuit diagram of an amplifier circuit of the turbo molecular pump illustrated inFig. 1.Fig. 3 is a time chart illustrating control of an amplifier control circuit in a case where a current command value is larger than a detection value.Fig. 4 is a time chart illustrating control of an amplifier control circuit in a case where a current command value is smaller than a detection value.Fig. 5 is a front view of a hermetic connector.Fig. 6 is a block diagram illustrating an electrical configuration of the turbo molecular pump according to the present embodiment.Fig. 7 is a cross-sectional view of a base portion as viewed from the inside of the turbo molecular pump.Fig. 8 is a plan view of a first vacuum-side sensor module.Fig. 9 is a plan view of a second vacuum-side sensor module.Fig. 10 is a block diagram illustrating an electrical configuration of a turbo molecular pump according to a first modification.Fig. 11 is a block diagram illustrating an electrical configuration of a turbo molecular pump according to a second modification.Fig. 12 is a block diagram illustrating an electrical configuration of a turbo molecular pump according to a third modification.[Description of Embodiments]

[0016] Hereinafter, a vacuum pump will be described with reference to the drawings by taking a turbo molecular pump as an example.

[0017] Fig. 1 illustrates a longitudinal cross-sectional view of a turbo molecular pump 100(pump main body). In Fig. 1 , in the turbo molecular pump 100, an inlet port 101 is formed at an upper end of a cylindrical outer cylinder 127 as a casing. Inside an outer cylinder 127, a rotating body 103 (rotor) in which a plurality of rotor blades 102 (102a, 102b, 102c...), which are turbine blades for sucking and exhausting gas, are radially formed in multiple stages in a peripheral portion is provided. A rotor shaft 113 is attached to the center of the rotating body 103, and the rotor shaft 113 is floated in the air, supported, and positionally controlled by, for example, a five-axis control magnetic bearing. The rotating body 103 is generally made of metal such as aluminum, an aluminum alloy, or stainless steel.

[0018] In an upper radial electromagnet 104, four electromagnets are arranged in pairs on the X axis and the Y axis. Four upper radial sensors 107 are provided in proximity to the upper radial electromagnet 104 and corresponding to the upper radial electromagnets 104, respectively. As the upper radial sensor 107, for example, an inductance sensor having a conductive winding, an eddy current sensor, or the like is used, and the position of the rotor shaft 113 is detected on the basis of a change in inductance of the conductive winding that changes according to the position of the rotor shaft 113. This upper radial sensor 107 is configured to detect the radial displacement of the rotor shaft 113, i.e. the rotating body 103 fixed thereto, and to send it to a control device 200.

[0019] In the control device 200, for example, a compensation circuit having a PID adjustment function generates an excitation control command signal of the upper radial electromagnet 104 on the basis of a position signal detected by the upper radial sensor 107, and an amplifier circuit 150 (described later) illustrated in Fig. 2 performs excitation control of the upper radial electromagnet 104 on the basis of the excitation control command signal, whereby the upper radial position of the rotor shaft 113 is adjusted.

[0020] The rotor shaft 113 is formed of a high-permeability material (Iron, stainless steel, etc.) or the like, and is attracted by the magnetic force of the upper radial electromagnet 104. Such adjustment is performed independently in the X axis direction and the Y axis direction. A lower radial electromagnet 105 and a lower radial sensor 108 are disposed similarly to the upper radial electromagnet 104 and the upper radial sensor 107, and the lower radial position of the rotor shaft 113 is adjusted similarly to the upper radial position.

[0021] Further, axial electromagnets 106A and 106B are arranged with a disc-shaped metal disc 111 provided in the lower part of the rotor shaft 113 interposed therebetween in a vertical direction. The metal disc 111 is made of a high-permeability material such as iron. An axial sensor 109 is provided to detect the axial displacement of the rotor shaft 113, andits axial position signal is configured to be sent to the control device 200.

[0022] Then, in the control device 200, for example, a compensation circuit having a PID adjustment function generates an excitation control command signal of each of the axial electromagnet 106A and the axial electromagnet 106B on the basis of the axial position signal detected by the axial sensor 109, and the amplifier circuit 150 performs excitation control on each of the axial electromagnet 106A and the axial electromagnet 106B on the basis of these excitation control command signals, so that the axial electromagnet 106A attracts the metal disc 111 upward by magnetic force, the axial electromagnet 106B attracts the metal disc 111 downward, and the axial position of the rotor shaft 113 is adjusted.

[0023] In this manner, the control device 200 appropriately adjusts the magnetic force exerted by the axial electromagnets 106A and 106B on the metal disc 111 , magnetically floats the rotor shaft 113 in the axial direction, and holds the rotor shaft in the space in a non-contact manner. The amplifier circuit 150 that performs excitation control on the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B will be described later.

[0024] On the other hand, a motor 121 includes a plurality of magnetic poles arranged circumferentially so as to surround the rotor shaft 113. Each magnetic pole is controlled by the control device 200 to rotationally drive the rotor shaft 113 via an electromagnetic force acting between the magnetic pole and the rotor shaft 113. A rotational speed sensor (not illustrated) such as a Hall element, a resolver, or an encoder is incorporated in the motor 121 , and the rotational speed of the rotor shaft 113 is detected by a detection signal of the rotational speed sensor.

[0025] Further, for example, a phase sensor (not illustrated) is attached in the vicinity of the lower radial sensor 108 to detect the phase of rotation of the rotor shaft 113. The control device 200 detects the position of the magnetic pole by using both the detection signals of the phase sensor and the rotational speed sensor.

[0026] A plurality of stator blades 123 (123a, 123b, 123c...) is disposed with a slight gap from the rotor blades 102 (102a, 102b, 102c...). The plurality of stages of rotor blades 102 and the plurality of stages of stator blades 123 constitute a turbo pump unit. The rotor blades 102 (102a, 102b, 102c...) are each formed to be inclined by a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transfer molecules of the exhaust gas downward by collision. The stator blades 123 (123a, 123b, 123c...) are made of, for example, a metal such as aluminum, iron, stainless steel, or copper, or a metal such as an alloy containing these metals as a component.

[0027] Similarly, the stator blades 123 are formed to be inclined by a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 and are alternately arranged with the steps of the rotor blades 102 toward the inside of the outer cylinder 127. The outer peripheral end of the stator blade 123 is supported in a state of being fitted between a plurality of stacked stator blade spacers 125 (125a, 125b, 125c...).

[0028] The stator blade spacer 125 is a ring-shaped member, and is made of, for example, a metal such as aluminum, iron, stainless steel, or copper, or a metal such as an alloy containing these metals as a component. The outer cylinder 127 is fixed to the outer periphery of the stator blade spacer 125 with a slight gap. A base portion 129 is disposed at a bottom portion of the outer cylinder 127. An outlet port 133 is formed in the base portion 129 and communicates with the outside. The exhaust gas having entered the inlet port 101 from the chamber (vacuum chamber) side and transferred toward the base portion 129 is sent to the outlet port 133.

[0029] Further, depending on the application of the turbo molecular pump 100, a threaded spacer 131 functioning as a thread groove pump portion is disposed between the lower portion of a stator blade spacer 125 and a base portion 129. The threaded spacer 131 is a cylindrical member made of metal such as aluminum, copper, stainless steel, iron, or an alloy containing these metals as a component, and a plurality of spiral thread grooves 131a are engraved on an inner peripheral surface thereof. The direction of the spiral of the thread groove 131a is a direction in which molecules of the exhaust gas are transferred toward an outlet port 133 when the molecules move in the rotation direction of the rotating body 103. A cylindrical portion 102d of the rotating body 103 is suspended from a lowermost portion of the rotor blade 102 (102a, 102b, 102c...). The outer peripheral surface of the cylindrical portion 102d has a cylindrical shape and protrudes toward the inner peripheral surface of the threaded spacer 131 and is close to the inner peripheral surface of the threaded spacer 131 with a predetermined gap. The exhaust gas transferred to the thread groove 131a by the rotor blade 102 and the stator blade 123 is guided by the thread groove 131a and sent to the base portion 129.

[0030] The base portion 129 is a disc-shaped member constituting a base portion of the turbo molecular pump 100, and is generally made of metal such as iron, aluminum, or stainless steel. Since the base portion 129 physically holds the turbo molecular pump 100 and also has a function of a heat conduction path, it is desirable to use a rigid metal having high thermal conductivity such as iron, aluminum, or copper.

[0031] In the configuration, when the rotor blades 102 are rotationally driven together withthe rotor shaft 113 by a motor 121 , the exhaust gas is sucked from the chamber through an inlet port 101 by the action of the rotor blades 102 and the stator blades 123. The rotation speed of the rotor blade 102 is usually 20,000 rpm to 90,000 rpm, and the peripheral speed at the 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 blades 102 and the stator blades 123 and is transferred to the base portion 129. At this time, the temperature of the rotor blade 102 increases due to frictional heat generated when the exhaust gas comes into contact with the rotor blade 102, conduction of heat generated by the motor 121 , and the like, but this heat is transmitted to the stator blade 123 side by radiation, conduction by gas molecules of the exhaust gas, or the like.

[0032] The stator blade spacers 125 are joined to each other at the outer peripheral portion, and transmit heat received by the stator blades 123 from the rotor blades 102, frictional heat generated when the exhaust gas comes into contact with the stator blades 123, and the like to the outside.

[0033] In the above description, the threaded spacer 131 is disposed on the outer periphery of the cylindrical portion 102d of the rotating body 103, and the thread groove 131a is engraved on the inner peripheral surface of the threaded spacer 131. However, conversely, a thread groove may be engraved on the outer peripheral surface of the cylindrical portion 102d, and a spacer having a cylindrical inner peripheral surface may be disposed around the thread groove.

[0034] In addition, depending on the application of the turbo molecular pump 100, the periphery of the electric unit is covered with a stator column 122 so that the gas sucked from the inlet port 101 does not enter the electric unit including the upper radial electromagnet 104, the upper radial sensor 107, the motor 121 , the lower radial electromagnet 105, the lower radial sensor 108, the axial electromagnets 106A and 106B, the axial sensor 109, and the like, and the inside of the stator column 122 may be kept at a predetermined pressure by the purge gas.

[0035] In this case, a pipe (not illustrated) is disposed in the base portion 129, and the purge gas is introduced through the pipe. The introduced purge gas is delivered to the outlet port 133 through a gap between a protection bearing 120 and the rotor shaft 113, between the rotor and the stator of the motor 121 , and between the cylindrical portion on the inner circumferential side of the rotor blade 102 and a stator column 122. As illustrated in Fig. 1 , the stator column 122 is erected at the center position of the base portion 129. In the present embodiment, a water cooling tube 149 as a cooling means is provided in thebase portion 129. By supplying cooling water to the water cooling tube 149, the base portion 129 and the stator column 122 are maintained at suitable temperatures.

[0036] Here, the turbo molecular pump 100 requires identification of a model and control on the basis of individual adjusted unique parameter (for example, various characteristics corresponding to the model). In order to store this control parameter, the turbo molecular pump 100 includes an electronic circuit unit 141 in its main body. The electronic circuit unit 141 includes a semiconductor memory such as an EEP-ROM, electronic components such as a semiconductor element for accessing the semiconductor memory, a substrate 143 for mounting the semiconductor memory, and the like. The electronic circuit unit 141 is accommodated in a lower portion of a rotational speed sensor (not illustrated), for example, in the vicinity of the center of the base portion 129 constituting the lower portion of the turbo molecular pump 100, and is closed by an airtight bottom lid 145.

[0037] A bottom lid 145 is provided with a hermetic connector 10 (see Fig. 7). The hermetic connector 10 is used for connection between a control device 200 and the turbo molecular pump 100.

[0038] Incidentally, in the process of manufacturing a semiconductor, some process gases introduced into the chamber have a property of becoming solid when the pressure thereof becomes higher than a predetermined value or the temperature thereof becomes lower than a predetermined value. Inside the turbo molecular pump 100, the pressure of the exhaust gas is the lowest at the inlet port 101 and the highest at the outlet port 133. When the pressure of the process gas becomes higher than a predetermined value or the temperature of the process gas becomes lower than a predetermined value while the process gas is being transferred from the inlet port 101 to the outlet port 133, the process gas becomes solid and adheres and accumulates inside the turbo molecular pump 100.

[0039] For example, in a case where SiCk is used as a process gas in an Al etching apparatus, it can be seen from the vapor pressure curve that a solid product (e.g., AlCh) is precipitated at low vacuum (760 torr to 10’2torr) and low temperature (about 20 °C), adheres inside the turbo molecular pump 100. As a result, when a precipitate of the process gas is deposited inside the turbo molecular pump 100, the deposit narrows the pump flow path and causes a decrease in performance of the turbo molecular pump 100. Then, the product described above is likely to solidify and adhere in the vicinity of the outlet port 133 or in the vicinity of the threaded spacer 131 at a portion where the pressure is high.

[0040] Therefore, in order to solve this problem, the control device 20 maintains thetemperature of the base portion 129 at a constant high temperature (set temperature) by a temperature management system (hereinafter, referred to as a TMS) described below.

[0041] Next, with regard to the turbo molecular pump 100 configured as described above, the amplifier circuit 150 for performing excitation control on the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B will be described. A circuit diagram of the amplifier circuit 150 is illustrated in Fig. 2.

[0042] In Fig. 2, one end of an electromagnet winding 151 constituting the upper radial electromagnet 104 and the like is connected to a positive electrode 171a of a power supply 171 via a transistor 161 , and the other end thereof is connected to a negative electrode 171 b of the power supply 171 via a current detection circuit 181 and a transistor 162. The transistors 161 and 162 are so-called power MOSFETs, and have a structure in which a diode is connected between the source and the drain.

[0043] At this time, in the transistor 161 , a cathode terminal 161a of the diode is connected to the positive electrode 171a, and an anode terminal 161b is connected to one end of the electromagnet winding 151. In the transistor 162, a cathode terminal 162a of the diode is connected to the current detection circuit 181 , and an anode terminal 162b is connected to the negative electrode 171 b.

[0044] On the other hand, a current regeneration diode 165 has a cathode terminal 165a connected to one end of the electromagnet winding 151 and an anode terminal 165b connected to the negative electrode 171 b. Similarly, a cathode terminal 166a of a current regeneration diode 166 is connected to the positive electrode 171a, and an anode terminal 166b thereof is connected to the other end of the electromagnet winding 151 via the current detection circuit 181 . The current detection circuit 181 includes, for example, a current sensor of a Hall sensor type or an electric resistance element.

[0045] The amplifier circuit 150 configured as described above corresponds to one electromagnet. Therefore, in a case where the magnetic bearings are controlled by five axes and the total number of the electromagnets 104, 105, 106A, and 106B is 10, a similar amplifier circuit 150 is configured for each of the electromagnets, and ten amplifier circuits 150 are connected in parallel to the power supply 171.

[0046] Furthermore, an amplifier control circuit 191 includes, for example, a digital signal processor unit (hereinafter, referred to as a DSP unit) not illustrated in the drawing of the control device 200, and the amplifier control circuit 191 switches on / off of the transistors 161 and 162.

[0047] The amplifier control circuit 191 compares a current value detected by the currentdetection circuit 181 (a signal reflecting the current value is referred to as a current detection signal 191c) with a predetermined current command value. The magnitude (pulse width times Tp1 and Tp2) of the pulse width generated in a control cycle Ts that is one cycle of the PWM control is determined on the basis of the comparison result. As a result, gate drive signals 191a and 191 b having the pulse widths are output from the amplifier control circuit 191 to the gate terminals of the transistors 161 and 162.

[0048] Note that it is necessary to control the position of the rotating body 103 at a high speed and with a strong force when the rotating body 103 passes through the resonance point during acceleration operation of the rotational speed of the rotating body, when a disturbance occurs during constant speed operation, or the like. Therefore, a voltage of, for example, about 50 V is used as the power supply 171 so that the current flowing through the electromagnet winding 151 can be rapidly increased (or decreased). In addition, a capacitor is usually connected between the positive electrode 171a and the negative electrode 171 b of the power supply 171 in order to stabilize the power supply 171 (not illustrated).

[0049] In such a configuration, when both the transistors 161 and 162 are turned on, the current (hereinafter, referred to as electromagnet current iL) flowing through the electromagnet winding 151 increases, and when both are turned off, the electromagnet current iL decreases.

[0050] In addition, when one of the transistors 161 and 162 is turned on and the other is turned off, a so-called flywheel current is held. Then, by causing the flywheel current to flow through the amplifier circuit 150 in this manner, the hysteresis loss in the amplifier circuit 150 can be reduced, and the power consumption of the entire circuit can be suppressed low. By controlling the transistors 161 and 162 in this manner, high-frequency noise such as harmonics generated in the turbo molecular pump 100 can be reduced. Furthermore, the electromagnet current iL flowing through the electromagnet winding 151 can be detected by measuring the flywheel current with the current detection circuit 181 .

[0051] That is, in a case where the detected current value is smaller than the current command value, as illustrated in Fig. 3, only once in the control cycle Ts (for example, 100 ps), both the transistors 161 and 162 are turned on by the time corresponding to the pulse width time Tp1 . Therefore, the electromagnetic current iL during this period increases toward a current value iLmax (not illustrated) that can flow from the positive electrode 171a to the negative electrode 171b via the transistors 161 and 162.

[0052] On the other hand, in a case where the detected current value is larger than thecurrent command value, as illustrated in Fig. 4, both the transistors 161 and 162 are turned off only once in the control cycle Ts for the time corresponding to the pulse width time Tp2. Therefore, the electromagnet current iL during this period decreases toward a current value iLmin (not illustrated) that can be regenerated from the negative electrode 171 b to the positive electrode 171 a via the diodes 165 and 166.

[0053] In either case, either one of the transistors 161 and 162 is turned on after the pulse width times Tp1 and Tp2 elapse. Therefore, during this period, the flywheel current is held in the amplifier circuit 150.

[0054] As illustrated in Fig. 5, the hermetic connector 10 includes a plurality of smalldiameter pins 11 A and large-diameter pins 11 B to be electrically connected, a connector base portion 13 having an oblong frame shape surrounding the plurality of pins 11 A and 11 B, and an insulating portion 14 electrically insulating the plurality of pins 11 A and 11 B.

[0055] In the present embodiment, the pins 11 A and 11 B are each formed in an elongated cylindrical shape, but the shape thereof is not limited. For example, the pins 11 A and 11 B may have a cylindrical shape having a step in which cylinders having different diameters are coaxially arranged and integrated, or may be formed in a prismatic shape instead of the cylindrical shape.

[0056] The connector base portion 13 is made of a metal material such as stainless steel. The connector base portion 13 is provided with holes 18 for bolt-fixing to the bottom lid 145 of the turbo molecular pump 100 at four comers. The connector base portion 13 has a left and right semicircular rectangular opening 13a inside the hole 18. Although the connector base portion 13 is formed in a plate shape, the shape thereof is not limited. Any shape of connector base portion can be employed.

[0057] The insulating portion 14 is made of a glass material having an insulating property. The insulating portion 14 fills the opening 13a of the connector base portion 13. The insulating portion 14 has a plurality of through holes 15 through which the plurality of pins 11 A and 11 B pass. The through hole 15 is a through hole formed of a circumferential surface that penetrates the insulating portion 14 and is in close contact with the shapes of the pins 11A and 11 B.

[0058] The insulating portion 14 holds the pins 11 A and 11 B such that one end sides of the plurality of pins 11 A and 11 B are located outside the turbo molecular pump 100 and the other end sides are located inside the turbo molecular pump 100.

[0059] The other ends of the plurality of pins 11 A and 11 B located inside the turbo molecular pump 100 are electrically connected to one ends of lead wires (not illustrated) to bedescribed later. Here, the lead wire is a linear member that transmits power and electric signals, and is a concept including a cable regardless of a material.

[0060] <Electrical configuration of vacuum pump>Next, an electrical configuration of the turbo molecular pump 100 according to a first embodiment of the present invention will be described in detail.

[0061] Fig. 6 is a block diagram of the turbo molecular pump 100 according to the first embodiment. The control device 200 (external device) connected to the turbo molecular pump 100 includes hardware including a CPU that performs various calculations and the like, a storage device such as a ROM or an HDD that stores a program for executing calculations by the CPU, a RAM that is a work area when the CPU executes a program, and a communication interface that is an interface when data is transmitted to and received from another device, and software stored in the storage device and executed by the CPU.

[0062] The turbo molecular pump 100 includes the hermetic connector 10, vacuum-side thermistors 21 to 23 (physical sensor), an atmospheric-side thermistor 24 (physical sensor), a first vacuum-side sensor module 25 to a third vacuum-side sensor module 27, an atmospheric-side sensor module 28, a crystal oscillator 29 (physical sensor), and serial communication buses 31 to 34.

[0063] The vacuum-side thermistors 21 to 23 are provided inside the turbo molecular pump 100. More specifically, the vacuum-side thermistors 21 to 23 are provided in a portion of vacuum or close to vacuum of the turbo molecular pump 100, in other words, a portion having a pressure lower than the atmospheric pressure, and is provided, for example, in the inlet port 101 , between the rotor blade 102 and the stator blade 123, in the cylindrical portion 102d, or the like.

[0064] The atmospheric-side thermistor 24 is provided outside the turbo molecular pump 100. In other words, the atmospheric-side thermistor 24 is provided at a position in contact with the atmosphere, and is provided, for example, on the outer peripheral surface of the outer cylinder 127, the bottom surface portion of the base portion 129, or the like.

[0065] The control device 200 performs TMS based on digital detection data obtained by converting an analog signal output from the atmospheric-side thermistor 24 into a digital signal. In the case of performing the TMS, for example, a heater (not illustrated) or an annular water cooling tube 149 is disposed on the outer periphery of the base portion 129 or the like, and the control device 200 controls heating of the heater or cooling by the water cooling tube 149 so as to keep the temperature of the base portion 129 at a constant hightemperature (set temperature).

[0066] The control device 200 also controls heating of the heater and cooling by the water cooling tube 149 based on digital detection data obtained by converting an analog signal output from the vacuum-side thermistors 21 to 23 into a digital signal and an operating state of the turbo molecular pump 100. In addition, the control device 200 performs control to notify information indicating a warning or the like when the turbo molecular pump 100 is in the operating state and in a low-temperature control state in which the temperature is lowered to a predetermined temperature based on the signals detected from the vacuumside thermistors 21 to 23.

[0067] As illustrated in Fig. 7, the first vacuum-side sensor module 25 (first circuit board) is disposed inside the base portion 129. Fig. 7 is a cross-sectional view of the base portion 129 as viewed from the other end side (the inner side of the turbo molecular pump 100) of the hermetic connector 10. The first vacuum-side sensor module 25 is connected to the hermetic connector 10. A serial communication bus 33 is connected to the hermetic connector 10. The serial communication bus 33 is for performing data communication with the control device 200 via the hermetic connector 10.

[0068] The first vacuum-side sensor module 25 is electrically connected to the second vacuum-side sensor module 26 (second circuit board) via a serial communication bus 31 , and the second vacuum-side sensor module 26 is electrically connected to the third vacuum-side sensor module 27 via the serial communication bus 32. In other words, the first vacuum-side sensor module 25 to the third vacuum-side sensor module 27 are daisy- chained via the serial communication buses 31 and 32.

[0069] The serial communication buses 31 to 34 include two communication lines and two power lines. As the serial communication buses 31 to 34 and a serial transfer circuit 55 to be described later, for example, those of the RS-485 standard are used.

[0070] As illustrated in Fig. 8, in the first vacuum-side sensor module 25, an input port 51 , an output port 52, an extension port 53, a signal conversion circuit 54, a serial transfer circuit 55, and a detection circuit 56 are mounted on a substrate having a rectangular shape. Each of the signal conversion circuit 54, the serial transfer circuit 55, and the detection circuit 56 may include one integrated circuit or may include a plurality of electronic components.

[0071] In the present embodiment, the first vacuum-side sensor module 25 includes sixteen input ports 51 , four output ports 52, and four extension ports 53. The output port 52 and the extension port 53 are arranged on a straight line on one side 25a of the first vacuum-side sensor module 25. On the other hand, the input ports 51 are arranged in a straight line on the other side 25b side of the first vacuum-side sensor module 25 facing the one side 25a.

[0072] Both ends of the vacuum-side thermistors 21 to 23 are electrically connected to the input port 51 of the first vacuum-side sensor module 25 via two conductive wires (not illustrated). In other words, in the first vacuum-side sensor module 25, a total of six input ports 51 are used for electrical connection with the vacuum-side thermistors 21 to 23.

[0073] The extension port 53 is electrically connected to the serial communication bus 31 , and the output port 52 is electrically connected to the pins 11 A and 11 B of the hermetic connector 10. The electrical connection between the output port 52 and the pins 11 A and 11 B may be connected via a lead wire, or the pins 11 A and 11 B may be fitted and connected to the output port 52.

[0074] The serial communication bus 33 connected to the hermetic connector 10 and configured to perform data communication with the control device 200 includes two communication lines as described above, and transmits digital detection data to be described later through these two communication lines. For this reason, the number of data transmission pins used for transmission of the digital detection data among the pins 11 A and 11 B of the hermetic connector 10 used for connection with the serial communication bus 33 is also two (2). The total number five (5) of the vacuum-side thermistors 21 to 23, which are physical sensors provided in the turbo molecular pump 100, the atmospheric-side thermistors 24, and the crystal oscillators 29 is larger than the number two (2) of these data transmission pins.

[0075] The detection circuit 56 detects detection data from analog signals output from the respective vacuum-side thermistors 21 to 23. The detection circuit 56 is connected to an external power supply via power lines of the serial communication buses 31 and 32 connected to the extension port 53 and the second and third vacuum-side sensor modules 26 and 27. The external power supply also applies a voltage to the crystal oscillator 29 and the atmospheric-side sensor module 28.

[0076] The detection circuit 56 includes, for example, a resonance circuit connected in series or in parallel with the vacuum-side thermistors 21 to 23. A voltage is applied to the resonance circuit by an external power supply. As a result, the detection circuit 56 can obtain detection data of an analog signal output from one ends of the vacuum-side thermistors 21 to 23.

[0077] In a case where the detection circuit 56 includes a resonance circuit, the detectiondata output from the vacuum-side thermistors 21 to 23 has a cycle that varies depending on the temperatures of the vacuum-side thermistors 21 to 23. In other words, the temperatures detected by the vacuum-side thermistors 21 to 23 are expressed as a function of a period based on detection data output from the vacuum-side thermistors 21 to 23.

[0078] The signal conversion circuit 54 is an analog-digital conversion circuit that converts an analog signal into a digital signal. The signal conversion circuit 54 converts the detection data detected by the detection circuit 56 into digital detection data as a digital signal. The signal conversion circuit 54 converts the analog signal into a digital signal represented by a predetermined bit number by sampling and quantizing the analog signal.

[0079] The serial transfer circuit 55 sequentially transmits and receives data including the digital detection data converted by the signal conversion circuit 54 as a serial signal by one bit using one or two communication lines. In the present embodiment, the serial transfer circuit 55 transmits and receives data using two communication lines provided in the serial communication buses 31 to 34.

[0080] The serial signal including the digital detection data detected by the detection circuit 56 is output from the output port 52, and is output to the control device 200 via the hermetic connector 10 and the serial communication bus 33.

[0081] In Fig. 8, in order to prevent complication, only one detection circuit 56 is illustrated in the first vacuum-side sensor module 25, but the present invention is not limited thereto, and a plurality of detection circuits 56 may be provided. In this case, in the first vacuumside sensor module 25, for example, the detection circuit 56 is provided according to the type of the analog signal output from each of the plurality of vacuum-side thermistors 21 to 23. Alternatively, instead of providing the plurality of detection circuits 56 only in the first vacuum-side sensor module 25, the plurality of detection circuits 56 may be provided in a distributed manner in the first vacuum-side sensor module 25 to the third vacuum-side sensor module 27.

[0082] As illustrated in Fig. 9, the second vacuum-side sensor module 26 (second circuit board) has a configuration similar to that of the first vacuum-side sensor module 25 except that a detection circuit 57 is mounted instead of the detection circuit 56. The detection circuit 57 may include one integrated circuit or a plurality of electronic components.

[0083] The detection circuit 57 detects detection data from the analog signal of the crystal oscillator 29. In other words, the detection circuit 57 is a detection circuit provided according to a type of an analog signal different from the detection circuit 56. Similarly tothe detection circuit 56 of the first vacuum-side sensor module 25, the detection circuit 57 is connected to an external power supply via the power line of the serial communication bus 32 and the third vacuum-side sensor module 27. A voltage is applied from the detection circuit 57 to the crystal oscillator 29. The crystal oscillator 29 includes a crystal oscillator, and oscillates in a cycle according to an ambient temperature when a predetermined voltage is applied from the detection circuit 57. In other words, the temperature detected by the crystal oscillator 29 is expressed as a function of a period based on the detection data output from the crystal oscillator 29. As a result, the detection circuit 57 can obtain detection data of an analog signal output from one end of the crystal oscillator 29. The signal conversion circuit 54 converts the detection data detected by the detection circuit 57 into digital detection data as a digital signal.

[0084] The serial signal including the digital detection data detected by the detection circuit 57 is output from the output port 52, and is output to the control device 200 via the serial communication bus 31 , the first vacuum-side sensor module 25, the hermetic connector 10, and the serial communication bus 33.

[0085] The atmospheric-side sensor module 28 has the same configuration as the first vacuum-side sensor module 25, and is provided outside the turbo molecular pump 100. The atmospheric-side sensor module 28 is disposed outside the base portion 129, for example.

[0086] Both ends of the atmospheric-side thermistor 24 are electrically connected to the input port 51 of the atmospheric-side sensor module 28. In addition, the extension port 53 of the atmospheric-side sensor module 28 is electrically connected to the pins 11 A and 11 B of the hermetic connector 10, and the output port 52 is electrically connected to the serial communication bus 34 (see Fig. 6).

[0087] The detection circuit 56 of the atmospheric-side sensor module 28 can obtain detection data (analog signal) output from one end of the atmospheric-side thermistor 24. The signal conversion circuit 54 converts the detection data detected by the detection circuit 56 into digital detection data as a digital signal. The serial transfer circuit 55 transmits and receives data including the digital detection data converted by the signal conversion circuit 54 as a serial signal. The serial signal including the digital detection data is output from the output port 52 and output to the control device 200 via the serial communication bus 34.

[0088] Next, effects of the present embodiment configured as described above will be described.

[0089] The turbo molecular pump 100 of the present embodiment detects detection data from an analog signal output from each of a plurality of physical sensors (vacuum-side thermistors 21 to 23, atmospheric-side thermistor 24, and crystal oscillator 29), converts the analog detection data into digital detection data as a digital signal, and outputs a serial signal including the digital detection data to the control device 200 by the serial communication buses 33 and 34, so that the number of pins used for data transmission can be reduced. Furthermore, since the turbo molecular pump 100 includes the signal conversion circuit 54 and the detection circuit 57, it is possible to cope with a case where the number or types of physical sensors is increased, and it is not necessary to increase the detection circuit on the control device 200 side. In other words, the turbo molecular pump 100 has high extendability.

[0090] In addition, the extension port 53 and the output port 52 are provided in the first vacuum-side sensor module 25, and the second vacuum-side sensor module 26 and the first vacuum-side sensor module 25 constituting the detection circuit 57 are connected via the extension port 53. Therefore, in a case where it is desired to increase the number or types of physical sensors, it is possible to cope with the case by newly connecting the second vacuum-side sensor module 26 and the third vacuum-side sensor module 27, and high extendability is obtained.

[0091] In addition, since the detection circuit 57 is provided according to the type of the analog signal output from each of the plurality of physical sensors, even in a case where the number or types of physical sensors are increased, each detection circuit can detect detection data, and has high extendability.

[0092] In addition, the first vacuum-side sensor module 25 has a rectangular shape, the output port 52 and the extension port 53 are arranged on the side of one side 25a, and the input port 51 is arranged on the other side 25b side facing the one side 25a. Therefore, the side to which the physical sensor is connected and the side to which the serial communication bus 31 for communication and the like are connected are separated, and wiring can be easily routed.

[0093] Since five (5) of physical sensors provided in the turbo molecular pump 100 is larger than two (2) of data transmission pins used for transmission of digital detection data among the pins 11 A and 11 B used for connection between the hermetic connector 10 and the serial communication bus 33, the number of pins 11 A and 11 B used for data transmission can be reduced.

[0094] (First modification)Next, a configuration of a turbo molecular pump 100 according to a first modification will be described. Fig. 10 is a block diagram of the turbo molecular pump 100 according to the first modification.

[0095] As illustrated in Fig. 10, the turbo molecular pump 100 according to the first modification includes a relay board 41 and a serial communication bus 42. Other configurations are basically the same as those of the turbo molecular pump 100 of the above embodiment illustrated in Fig. 6. The relay board 41 constitutes a part of the hermetic connector 10, and is electrically connected to the pins 11 A and 11 B of the hermetic connector 10. A connector (not illustrated) connected to the serial communication bus 42 is mounted on the relay board 41 . The atmospheric-side sensor module 28 is electrically connected to the relay board 41 via the serial communication bus 42. In other words, the relay board 41 relays the electrical connection between the control device 200 and the atmospheric-side sensor module 28.

[0096] Similarly to the above embodiment, both ends of the atmospheric-side thermistor 24 are electrically connected to the input port 51 of the atmospheric-side sensor module 28. The output port 52 of the atmospheric-side sensor module 28 is electrically connected to the serial communication bus 42.

[0097] The detection circuit 56 of the atmospheric-side sensor module 28 can obtain detection data (analog signal) output from one end of the atmospheric-side thermistor 24 as in the above embodiment. The signal conversion circuit 54 converts the detection data detected by the detection circuit 56 into digital detection data as a digital signal. The serial transfer circuit 55 transmits and receives data including the digital detection data converted by the signal conversion circuit 54 as a serial signal. The serial signal including the digital detection data is output from the output port 52, and is output to the control device 200 via the serial communication bus 42, the relay board 41 , the hermetic connector 10, and the serial communication bus 33.

[0098] In the turbo molecular pump 100 of the first modification configured as described above, transmission and reception of data with the control device 200 can be performed only by the serial communication bus 33. The number of cables connected to the control device 200 is reduced, and the same effects as those of the above embodiment can be obtained with a simple configuration.

[0099] (Second modification)Next, a configuration of a turbo molecular pump 100 according to a second modification will be described. Fig. 11 is a block diagram of the turbo molecular pump 100 according to the second modification.

[0100] As illustrated in Fig. 11 , the turbo molecular pump 100 according to the second modification includes an atmospheric-side thermistor 43. Other configurations are basically the same as those of the turbo molecular pump 100 of the first modification illustrated in Fig. 10. The atmospheric-side thermistor 43 is provided at a position different from the atmospheric-side thermistor 24 and outside the turbo molecular pump 100, and is provided, for example, on the outer peripheral surface of the outer cylinder 127, the bottom surface of the base portion 129, or the like.

[0101] In the second modification, the relay board 41 includes an input port 51 , and both ends of the atmospheric-side thermistor 43 are electrically connected. Further, in the second modification, the signal conversion circuit 54 and the detection circuit 56 are mounted on the relay board 41. In this case, the detection circuit 56 of the relay board 41 detects the detection data from the analog signal output from the atmospheric-side thermistor 43. The signal conversion circuit 54 converts the detection data detected by the detection circuit 56 into digital detection data as a digital signal. The serial signal including the digital detection data converted by the signal conversion circuit 54 is output to the control device 200 via the hermetic connector 10 and the serial communication bus 33.

[0102] In the turbo molecular pump 100 of the second modification configured as described above, since the detection circuit 56 is provided on the relay board 41 , even in a case where the atmospheric-side thermistor 43 is added in addition to the configuration of the first modification, it is not necessary to add a sensor module, a serial communication bus, and the like, and it is possible to easily cope with a design change of adding the atmospheric-side thermistor 43 in addition to the effect similar to the above embodiment.

[0103] (Third modification)Next, a configuration of a turbo molecular pump 100 according to a third modification will be described. Fig. 12 is a block diagram of the turbo molecular pump 100 according to the third modification.

[0104] As illustrated in Fig. 12, in the turbo molecular pump 100 according to the third modification, a serial communication bus 33 for performing data communication with the control device 200 is connected to the relay board 41 , not the pins 11 A and 11 B of thehermetic connector 10. Other configurations are basically the same as those of the turbo molecular pump 100 of the second modification illustrated in Fig. 11.

[0105] In the third modification, the relay board 41 includes a connector connected to the serial communication bus 42 and an output port, and the serial communication bus 33 is electrically connected to the output port. Similarly to the first modification, the relay board 41 is electrically connected to the pins 11 A and 11 B of the hermetic connector 10, and the atmospheric-side sensor module 28 is electrically connected thereto via the serial communication bus 42. In other words, the relay board 41 relays the electrical connection between the control device 200 and the atmospheric-side sensor module 28.

[0106] The serial signal including the digital detection data detected by the detection circuits 56 and 57 of the first and second vacuum-side sensor modules 25 and 26 and converted by the signal conversion circuit 54 is output to the control device 200 via the pins 11 A and 11 B of the hermetic connector 10, the relay board 41 , and the serial communication bus 33. In other words, the relay board 41 relays the electrical connection between the control device 200 and the first and second vacuum-side sensor modules 25 and 26.

[0107] In addition, the relay board 41 has connection terminals connected to the pins 11 A and 11 B of the hermetic connector 10. As a result, the relay board 41 converts connection by the pins 11 A and 11 B into connection (another connection mode) between the output port and the serial communication bus 33.

[0108] In addition, the detection circuit 56 of the atmospheric-side sensor module 28 can obtain detection data (analog signal) output from one end of the atmospheric-side thermistor 24 as in the above embodiment. The signal conversion circuit 54 converts the detection data detected by the detection circuit 56 into digital detection data as a digital signal. The serial signal including the digital detection data is output from the output port 52, and is output to the control device 200 via the serial communication bus 42, the relay board 41 , and the serial communication bus 33.

[0109] In the turbo molecular pump 100 of the third modification configured as described above, the serial communication bus 33 is connected to the relay board 41 , and transmission and reception of data with the control device 200 can be performed only by the serial communication bus 33. Therefore, the number of cables connected to the control device 200 is reduced, and the same effects as those of the above embodiment can be obtained with a simple configuration.

[0110] Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the presentinvention, and all technical matters included in the technical idea described in the claims are the subject of the present invention. Although the above embodiments illustrate preferred examples, those skilled in the art can realize various alternative examples, modifications, variations, combinations, or improvements from the contents disclosed in the present specification, which are included in the technical scope described in the appended claims.

[0111] For example, the physical sensor provided in the turbo molecular pump 100 is not limited to a thermistor and a crystal oscillator, and may be a position sensor for detecting a position, a rotation sensor for detecting a rotation angle, or the like.

[0112] In addition, the shape of the connector base portion of the hermetic connector is not limited to the above-described round frame shape, and any shape of the connector base portion such as a horizontally long rectangular frame shape can be adopted. In addition, the shape of the connector base portion may be a box shape instead of a frame shape.[Reference Signs List]

[0113] 10 Hermetic connector11A Small-diameter pin (pin)11 B Large-diameter pin (pin)21 to 23 Vacuum-side thermistor24, 43 Atmospheric-side thermistor25 First vacuum-side sensor module (first circuit board)26 Second vacuum-side sensor module (second circuit board)27 Third vacuum-side sensor module28, 44 Atmospheric-side sensor module29 Crystal oscillator31 to 34, 42 Serial communication bus41 Relay board51 Input port52 Output port53 Extension port54 Signal conversion circuit55 Serial transfer circuit56 Detection circuit57 Detection circuit100 Turbo molecular pump (vacuum pump)

Claims

CLAIMS1 . A vacuum pump comprising: a pump main body configured that sucks and exhausts gas; a plurality of physical sensors provided in the pump main body; and a connector used for connection with an external device, wherein the vacuum pump includes: a detection circuit that detects detection data from an analog signal output from each of the plurality of physical sensors; a signal conversion circuit that converts the detection data into digital detection data as a digital signal; and a serial communication bus that performs data communication with the external device via the connector, and the serial communication bus outputs a serial signal including the digital detection data.2 The vacuum pump according to claim 1 , further comprising: a first circuit board constituting the signal conversion circuit; and a second circuit board having an input port, to which the analog signal is input, and constituting the detection circuit, wherein the first circuit board includes: an extension port that is connected to the second circuit board; and an output port that outputs the digital detection data.3 The vacuum pump according to claim 2, wherein the detection circuit is provided according to a type of the analog signal output from each of the plurality of physical sensors.4 The vacuum pump according to claim 2, wherein the first circuit board has a rectangular outer shape, the output port and the extension port are disposed on one side of the first circuit board, and the input port is disposed on another side of the first circuit board facing the oneside.

5. The vacuum pump according to any one of claims 1 to 4, wherein a number of the physical sensors provided in the pump main body is larger than a number of data transmission pins used for transmission of the digital detection data, among pins of the connector used for connection with the serial communication bus.

6. The vacuum pump according to any one of claims 1 to 4, wherein the connector includes a relay board that relays electrical connection with the external device, and the detection circuit and the signal conversion circuit perform data communication with the external device via the relay board.

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