vacuum pump

Abstract

To reduce the number of pins used for data transmission and to provide a highly expandable vacuum pump. [Solution] A vacuum pump comprising a pump body (100) for inhaling and exhausting gas, a plurality of physical sensors (21-23) provided on the pump body, and a connector (10) used for connecting to an external device (200), wherein the vacuum pump comprises a detection circuit (56) for detecting detection data from analog signals output from each of the plurality of physical sensors (21-23), a signal conversion circuit (54) for converting the detection data into digital detection data as a digital signal, and a serial communication bus (33) for data communication with an external device (200) via the connector (10), the serial communication bus (33) outputs a serial signal including digital detection data.

Description

Technical Field

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

Background Art

[0002] Generally, a vacuum pump typified by a turbo molecular pump includes a pump body for exhausting gas and a control device (external device) for controlling the pump body. The pump body is equipped with various physical sensors such as a thermistor for detecting temperature and a rotation sensor for detecting the rotation angle based on the change in magnetism. The control device receives the output from the physical sensors and controls the pump body.

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

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, since a large number of physical sensors are provided in vacuum pumps, the types of data transmitted from the pump body to the control device have also increased. When the pump body and the control device are connected by a parallel communication bus, the number of signal lines for data transmission 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 fixed, there is a possibility that it cannot cope with the increase in the pins required for data transmission.

[0006] Furthermore, in Patent Document 1, the pump body and the control device are connected by a serial communication bus, which reduces the number of pins required for data transmission. However, in Patent Document 1, the detection circuit that detects measured values ​​such as temperature and rotation angle based on the output of the physical sensor is located on the control device side, so increasing the number of physical sensors requires adding detection circuits on the control device side as well, resulting in low expandability.

[0007] Therefore, the main objective of the present invention is to reduce the number of pins used for data transmission and to provide a vacuum pump with high expandability. [Means for solving the problem]

[0008] To achieve the above objective, a first aspect of the present invention is a vacuum pump comprising a pump body for inhaling and exhausting gas, a plurality of physical sensors provided on the pump body, and a connector used for connecting to an external device, wherein the vacuum pump comprises a detection circuit for detecting detection data from analog signals output from each of the plurality of physical sensors, a signal conversion circuit for converting the detection data into digital detection data as a digital signal, and a serial communication bus for data communication with the external device via the connector, wherein the serial communication bus outputs a serial signal including the digital detection data.

[0009] In the above configuration, the system comprises a first circuit board that constitutes the signal conversion circuit and a second circuit board that constitutes the detection circuit and has an input port into which the analog signal is input, wherein the first circuit board has an expansion port connected to the second circuit board and an output port that outputs the digital detection data.

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

[0011] In the above configuration, the first circuit board has a rectangular shape, the output port and the expansion port are arranged on one side of the first circuit board, and the input port is arranged on the other side of the first circuit board opposite to the one side.

[0012] In the above configuration, the number of physical sensors provided on the pump body is greater than the number of data transmission pins used for transmitting the digital detection data among the pins of the connector used for connecting to the serial communication bus.

[0013] In the above configuration, the connector is equipped with a relay board that relays the electrical connection with the external device, and the detection circuit and the signal conversion circuit communicate data with the external device via the relay board. [Effects of the Invention]

[0014] According to the present invention, it is possible to reduce the number of pins used for data transmission and provide a vacuum pump with high expandability. Other problems, configurations, and effects will be clarified by the following description of embodiments. [Brief explanation of the drawing]

[0015] [Figure 1] This is a longitudinal cross-section of a turbomolecular pump. [Figure 2] Figure 1 is a circuit diagram of the amplifier circuit for the turbomolecular pump shown. [Figure 3] This is a time chart showing the control of the amplifier control circuit when the current command value is greater than the detected value. [Figure 4] This is a time chart showing the control of the amplifier control circuit when the current command value is smaller than the detected value. [Figure 5] This is a front view of a hermetic connector. [Figure 6] This is a block diagram showing the electrical configuration of the turbomolecular pump according to this embodiment. [Figure 7]It is a cross-sectional view of the base part seen from the inside of the turbo molecular pump. [Figure 8] It is a plan view of the first vacuum side sensor module. [Figure 9] It is a plan view of the second vacuum side sensor module. [Figure 10] It is a block diagram showing the electrical configuration of the turbo molecular pump according to Modification 1. [Figure 11] It is a block diagram showing the electrical configuration of the turbo molecular pump according to Modification 2. [Figure 12] It is a block diagram showing the electrical configuration of the turbo molecular pump according to Modification 3.

Embodiments for Carrying Out the Invention

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

[0017] [[ID=2,7]]A longitudinal sectional view of this turbo molecular pump 100 (pump body) is shown in FIG. 1. In FIG. 1, an intake port 101 is formed at the upper end of a cylindrical outer cylinder 127 which is an exterior body in the turbo molecular pump 100. And inside the outer cylinder 127, a rotating body 103 (rotor) having a plurality of rotating blades 102 (102a, 102b, 102c ···) which are turbine blades for sucking and exhausting gas is formed radially and in multiple stages on the circumferential part. A rotor shaft 113 is attached to the center of this rotating body 103, and this rotor shaft 113 is levitated and position-controlled in the air by, for example, a magnetic bearing with 5-axis control. The rotating body 103 is generally made of a metal such as aluminum or an aluminum alloy, or stainless steel.

[0018] The upper radial electromagnet 104 consists of four electromagnets arranged in pairs along the X and Y axes. Four upper radial sensors 107 are provided in close proximity to the upper radial electromagnet 104, and each sensor corresponds to one of the upper radial electromagnets 104. The upper radial sensors 107 are, for example, inductance sensors or eddy current sensors with conduction windings, and detect the position of the rotor shaft 113 based on the change in the inductance of these conduction windings, which changes according to the position of the rotor shaft 113. These upper radial sensors 107 are configured to detect the radial displacement of the rotor shaft 113, i.e., the rotating body 103 fixed to it, and send the data to the control device 200.

[0019] In this control device 200, for example, a compensation circuit having a PID adjustment function generates an excitation control command signal for the upper radial electromagnet 104 based on the position signal detected by the upper radial sensor 107, and the amplifier circuit 150 (described later) shown in Figure 2 controls the excitation of the upper radial electromagnet 104 based on this excitation control command signal, thereby adjusting the upper radial position of the rotor shaft 113.

[0020] The rotor shaft 113 is made of a high-permeability material (such as iron or stainless steel) and is attracted by the magnetic force of the upper radial electromagnet 104. This adjustment is performed independently in the X-axis and Y-axis directions. The lower radial electromagnet 105 and lower radial sensor 108 are arranged in the same way as the upper radial electromagnet 104 and upper radial sensor 107, and adjust the lower radial position of the rotor shaft 113 in the same way as the upper radial position.

[0021] Furthermore, axial electromagnets 106A and 106B are positioned above and below a disc-shaped metal disk 111 located at the bottom of the rotor shaft 113. The metal disk 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, and its axial position signal is sent to the control device 200.

[0022] Then, in the control device 200, for example, a compensation circuit having a PID adjustment function generates excitation control command signals for the axial electromagnets 106A and 106B based on the axial position signal detected by the axial sensor 109, and the amplifier circuit 150 excites the axial electromagnets 106A and 106B based on these excitation control command signals, so that the axial electromagnet 106A attracts the metal disk 111 upward with magnetic force, and the axial electromagnet 106B attracts the metal disk 111 downward, thereby adjusting the axial position of the rotor shaft 113.

[0023] Thus, the control device 200 appropriately adjusts the magnetic force exerted by the axial electromagnets 106A and 106B on the metal disk 111, causing the rotor shaft 113 to levitate axially and be held in contact with space. The amplifier circuit 150 that excites and controls the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B will be described later.

[0024] On the other hand, the motor 121 is equipped with multiple magnetic poles arranged circumferentially around the rotor shaft 113. Each magnetic pole is controlled by the control device 200 to rotate the rotor shaft 113 via the electromagnetic force acting between it and the rotor shaft 113. The motor 121 also incorporates a rotational speed sensor, such as a Hall element, resolver, or encoder (not shown), and the rotational speed of the rotor shaft 113 is detected by the detection signal from this rotational speed sensor.

[0025] Furthermore, for example, a phase sensor (not shown) is attached near the lower radial sensor 108 to detect the phase of rotation of the rotor shaft 113. The control device 200 uses both the detection signals from this phase sensor and the rotational speed sensor to detect the position of the magnetic pole.

[0026] Multiple fixed blades 123 (123a, 123b, 123c...) are arranged with small gaps between them and the rotating blades 102 (102a, 102b, 102c...). These multiple stages of rotating blades 102 and multiple stages of fixed blades 123 constitute the turbopump section. Each of the rotating blades 102 (102a, 102b, 102c...) is formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transfer exhaust gas molecules downward by collision. The fixed blades 123 (123a, 123b, 123c...) are made of metals such as aluminum, iron, stainless steel, copper, or alloys containing these metals as components.

[0027] Similarly, the fixed wing 123 is formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and is arranged alternately with the stages of the rotor blade 102 toward the inside of the outer cylinder 127. The outer edge of the fixed wing 123 is supported by being fitted between a plurality of stacked fixed wing spacers 125 (125a, 125b, 125c, etc.).

[0028] The fixed-wing spacer 125 is a ring-shaped member and is made of a metal such as aluminum, iron, stainless steel, or copper, or an alloy containing these metals as components. An outer cylinder 127 is fixed to the outer circumference of the fixed-wing spacer 125 with a small gap in between. A base portion 129 is provided at the bottom of the outer cylinder 127. An exhaust port 133 is formed in the base portion 129 and communicates with the outside. Exhaust gas that has entered the intake port 101 from the chamber (vacuum chamber) side and been transported toward the base portion 129 is sent to the exhaust port 133.

[0029] Furthermore, depending on the application of the turbomolecular pump 100, a threaded spacer 131, which functions as a threaded pump section, is provided between the lower part of the fixed-blade spacer 125 and the base section 129. The threaded spacer 131 is a cylindrical member made of a metal such as aluminum, copper, stainless steel, iron, or an alloy containing these metals, and has multiple spiral threads 131a engraved on its inner circumferential surface. The direction of the spiral of the threads 131a is such that when exhaust gas molecules move in the direction of rotation of the rotating body 103, these molecules are transported toward the exhaust port 133. A cylindrical section 102d hangs down from the lowest part of the rotating body 103 following the rotor blades 102 (102a, 102b, 102c...). The outer circumferential surface of this cylindrical section 102d is cylindrical and protrudes toward the inner circumferential surface of the threaded spacer 131, and is in close proximity to the inner circumferential surface of the threaded spacer 131 with a predetermined gap between them. The exhaust gas, which has been transferred to the screw groove 131a by the rotor blade 102 and the fixed blade 123, is guided through the screw groove 131a and sent to the base section 129.

[0030] The base portion 129 is a disc-shaped component that forms the base of the turbomolecular pump 100, and is generally made of a metal such as iron, aluminum, or stainless steel. The base portion 129 not only physically holds the turbomolecular pump 100 but also functions as a heat conduction path, so it is desirable to use a metal that is rigid and has high thermal conductivity, such as iron, aluminum, or copper.

[0031] In this configuration, when the rotor blade 102 is rotated by the motor 121 together with the rotor shaft 113, exhaust gas is drawn in from the chamber through the intake port 101 due to the action of the rotor blade 102 and the fixed blade 123. The rotational speed of the rotor blade 102 is usually 20,000 rpm to 90,000 rpm, and the peripheral speed at the tip of the rotor blade 102 reaches 200 m / s to 400 m / s. The exhaust gas drawn in from the intake port 101 passes between the rotor blade 102 and the fixed blade 123 and is transferred to the base section 129. At this time, the temperature of the rotor blade 102 rises due to frictional heat generated when the exhaust gas comes into contact with the rotor blade 102 and heat conduction generated by the motor 121, but this heat is transferred to the fixed blade 123 side by radiation or conduction by gas molecules of the exhaust gas.

[0032] The fixed-wing spacers 125 are joined to each other at their outer circumference, and they transmit heat received by the fixed wing 123 from the rotor blade 102, as well as frictional heat generated when exhaust gases come into contact with the fixed wing 123, to the outside.

[0033] In the above description, the threaded spacer 131 is positioned on the outer circumference of the cylindrical portion 102d of the rotating body 103, and a threaded groove 131a is engraved on the inner surface of the threaded spacer 131. However, conversely, there are also cases where a threaded groove is engraved on the outer circumference of the cylindrical portion 102d, and a spacer having a cylindrical inner surface is positioned around it.

[0034] Furthermore, depending on the application of the turbomolecular pump 100, the electrical components, which consist of an upper radial electromagnet 104, an upper radial sensor 107, a motor 121, a lower radial electromagnet 105, a lower radial sensor 108, axial electromagnets 106A, 106B, and an axial sensor 109, may be covered by a stator column 122 to prevent the gas drawn in from the intake port 101 from entering the electrical components, and the inside of this stator column 122 may be maintained at a predetermined pressure with purge gas.

[0035] In this case, piping (not shown) is provided in the base section 129, and purge gas is introduced through this piping. The introduced purge gas is sent to the exhaust port 133 through the gaps between the protective bearing 120 and the rotor shaft 113, between the rotor and stator of the motor 121, and between the stator column 122 and the inner cylindrical portion of the rotor blade 102. As shown in Figure 1, the stator column 122 is erected at the center of the base section 129. In this embodiment, a water cooling pipe 149 is provided in the base section 129 as a cooling means. Cooling water is supplied to this water cooling pipe 149, keeping the base section 129 and the stator column 122 at a suitable temperature.

[0036] Here, the turbomolecular pump 100 requires model identification and control based on individually adjusted unique parameters (e.g., characteristics corresponding to the model). To store these control parameters, the turbomolecular pump 100 is equipped with an electronic circuit section 141 within its body. The electronic circuit section 141 consists of electronic components such as semiconductor memory such as EEP-ROM and semiconductor elements for accessing it, and a substrate 143 for mounting them. This electronic circuit section 141 is housed, for example, below a rotational speed sensor (not shown) near the center of the base section 129 that constitutes the lower part of the turbomolecular pump 100, and is closed by an airtight bottom cover 145.

[0037] Furthermore, a hermetic connector 10 is provided on the bottom cover 145 (see Figure 7). The hermetic connector 10 is used to connect the control device 200 and the turbomolecular pump 100.

[0038] Incidentally, in the semiconductor manufacturing process, some process gases introduced into the chamber have the property of becoming solid when their pressure exceeds a predetermined value or their temperature falls below a predetermined value. Inside the turbomolecular pump 100, the exhaust gas pressure is lowest at the intake port 101 and highest at the exhaust port 133. If the process gas pressure exceeds a predetermined value or its temperature falls below a predetermined value while it is being transferred from the intake port 101 to the exhaust port 133, the process gas becomes solid and adheres to and accumulates inside the turbomolecular pump 100.

[0039] For example, if SiCl4 is used as the process gas in an Al etching apparatus, the low vacuum (760 [torr] ~ 10 -2 The vapor pressure curve shows that when the pressure is low (torr) and the temperature is low (approximately 20°C), solid products (e.g., AlCl3) precipitate and adhere to the inside of the turbomolecular pump 100. As a result, when precipitates of process gas accumulate inside the turbomolecular pump 100, these deposits narrow the pump flow path, causing a decrease in the performance of the turbomolecular pump 100. Furthermore, the aforementioned products were prone to solidifying and adhering in areas of high pressure, such as near the exhaust port 133 and near the threaded spacer 131.

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

[0041] Next, we will describe an amplifier circuit 150 that energizes and controls the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B of the turbomolecular pump 100 configured in this way. The circuit diagram of this amplifier circuit 150 is shown in Figure 2.

[0042] In Figure 2, the electromagnet winding 151, which constitutes the upper radial electromagnet 104, has one end connected to the positive terminal 171a of the power supply 171 via transistor 161, and the other end connected to the negative terminal 171b of the power supply 171 via current detection circuit 181 and transistor 162. Transistors 161 and 162 are so-called power MOSFETs, and have a structure in which a diode is connected between their source and drain.

[0043] In this configuration, transistor 161 has its diode cathode terminal 161a connected to the positive terminal 171a, and its anode terminal 161b connected to one end of the electromagnet winding 151. Transistor 162 has its diode cathode terminal 162a connected to the current detection circuit 181, and its anode terminal 162b connected to the negative terminal 171b.

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

[0045] The amplifier circuit 150 configured as described above corresponds to one electromagnet. Therefore, if the magnetic bearing is 5-axis controlled and there are a total of 10 electromagnets 104, 105, 106A, and 106B, a similar amplifier circuit 150 is configured for each electromagnet, and the 10 amplifier circuits 150 are connected in parallel to the power supply 171.

[0046] Furthermore, the amplifier control circuit 191 is configured, for example, by a digital signal processor (hereinafter referred to as the DSP section) of the control device 200 (not shown), and this amplifier control circuit 191 is configured to switch transistors 161 and 162 on and off.

[0047] The amplifier control circuit 191 compares the current value detected by the current detection circuit 181 (the signal reflecting this current value is called the current detection signal 191c) with a predetermined current command value. Based on this comparison, it determines the magnitude of the pulse width (pulse width time Tp1, Tp2) to be generated within the control cycle Ts, which is one period of PWM control. As a result, gate drive signals 191a and 191b with this pulse width are output from the amplifier control circuit 191 to the gate terminals of transistors 161 and 162.

[0048] Furthermore, when the rotating body 103 passes a resonance point during accelerated rotational speed operation, or when disturbances occur during constant-speed operation, it is necessary to control the position of the rotating body 103 with high speed and strong force. For this reason, a voltage of approximately 50V is used for 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 171b of the power supply 171 to stabilize the power supply 171 (not shown).

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

[0050] Furthermore, by turning one of transistors 161 and 162 on and the other off, a so-called flywheel current is maintained. By allowing this flywheel current to flow through the amplifier circuit 150, hysteresis loss in the amplifier circuit 150 can be reduced, and the overall power consumption of the circuit can be kept low. In addition, by controlling transistors 161 and 162 in this way, high-frequency noise such as harmonics generated in the turbomolecular pump 100 can be reduced. Moreover, by measuring this flywheel current with the current detection circuit 181, the electromagnet current iL flowing through the electromagnet winding 151 can be detected.

[0051] In other words, if the detected current value is smaller than the current command value, both transistors 161 and 162 are turned on only once during the control cycle Ts (e.g., 100 μs) for a duration corresponding to the pulse width time Tp1, as shown in Figure 3. Therefore, the electromagnet current iL during this period increases from the positive electrode 171a to the negative electrode 171b, towards the current value iLmax (not shown) that can flow through transistors 161 and 162.

[0052] On the other hand, if the detected current value is greater than the current command value, both transistors 161 and 162 are turned off only once during the control cycle Ts for a duration corresponding to the pulse width time Tp2, as shown in Figure 4. Therefore, during this period, the electromagnet current iL decreases from the negative electrode 171b towards the positive electrode 171a, towards a regenerative current value iLmin (not shown) via diodes 165 and 166.

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

[0054] As shown in Figure 5, the hermetic connector 10 has a plurality of electrically connected small-diameter pins 11A and large-diameter pins 11B, a horizontally elongated frame-shaped connector base portion 13 surrounding the plurality of pins 11A and 11B, and an insulating portion 14 that electrically insulates the plurality of pins 11A and 11B.

[0055] In this embodiment, pins 11A and 11B are each formed in the shape of an elongated cylinder, but their shape is not limited. For example, pins 11A and 11B may be cylindrical in shape with a step formed by arranging cylinders of different diameters coaxially and integrating them, or they may be formed in the shape of a rectangular prism instead of a cylinder.

[0056] The connector base portion 13 is made of a metal material such as stainless steel. The connector base portion 13 has holes 18 at its four corners for bolting to the bottom cover 145 of the turbomolecular pump 100. Inside the holes 18, the connector base portion 13 has semicircular rectangular openings 13a on the left and right sides. The connector base portion 13 is formed in a plate shape, but its shape is not limited. A connector base portion of any shape can be used.

[0057] The insulating portion 14 is made of an insulating glass material. The insulating portion 14 fills the opening 13a of the connector base portion 13. The insulating portion 14 has multiple through holes 15 through which multiple pins 11A and 11B pass. The through holes 15 are through holes that penetrate the insulating portion 14 and are composed of circumferential surfaces that are in close contact with the outer shapes of the pins 11A and 11B.

[0058] The insulating portion 14 holds the pins 11A and 11B such that one end of each pin 11A and 11B is located outside the turbomolecular pump 100 and the other end is located inside the turbomolecular pump 100.

[0059] The other ends of several pins 11A and 11B located inside the turbomolecular pump 100 are electrically connected to one end of a lead wire (not shown), which will be described later. Here, a lead wire is a linear component that transmits power or electrical signals, and the material is not specified; the concept also includes cables.

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

[0061] Figure 6 is a block diagram of the turbomolecular pump 100 according to the first embodiment. The control device 200 (external device) connected to the turbomolecular pump 100 consists of hardware including a CPU that performs various calculations, a storage device such as a ROM or HDD that stores programs for executing calculations by the CPU, RAM which is a work area when the CPU executes programs, and a communication interface which is an interface for sending and receiving data with other devices, and software stored in the storage device and executed by the CPU.

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

[0063] The vacuum-side thermistors 21-23 are located inside the turbomolecular pump 100. More specifically, the vacuum-side thermistors 21-23 are located in the vacuum or near-vacuum parts of the turbomolecular pump 100, in other words, in parts with a pressure lower than atmospheric pressure, for example, inside the intake port 101, between the rotor blades 102 and the fixed blades 123, and inside the cylindrical section 102d.

[0064] The atmospheric-side thermistor 24 is located outside the turbomolecular pump 100. In other words, the atmospheric-side thermistor 24 is located in a position that is exposed to the atmosphere, for example, on the outer surface of the outer cylinder 127 or on the bottom surface of the base portion 129.

[0065] The control device 200 performs TMS based on digital detection data obtained by converting the analog signal output from the atmospheric thermistor 24 into a digital signal. When performing TMS, for example, a heater (not shown) and an annular water cooling pipe 149 are placed around the outer circumference of the base portion 129, and the control device 200 controls the heating of the heater and the cooling of the water cooling pipe 149 to maintain the temperature of the base portion 129 at a constant high temperature (set temperature).

[0066] Furthermore, the control device 200 also controls the heating of the heater and the cooling of the water cooling pipe 149 based on digital detection data obtained by converting analog signals output from the vacuum-side thermistors 21-23 into digital signals, and the operating status of the turbomolecular pump 100. In addition, the control device 200, based on the signals detected from the vacuum-side thermistors 21-23, controls the device to notify warnings or other information if the turbomolecular pump 100 is operating and has reached a predetermined temperature (low-temperature control state).

[0067] As shown in Figure 7, the first vacuum-side sensor module 25 (first circuit board) is located inside the base portion 129. Figure 7 is a cross-sectional view of the base portion 129 as seen from the other end of the hermetic connector 10 (inside the turbomolecular pump 100). 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 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 a 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 together via serial communication buses 31 and 32.

[0069] Each of the serial communication buses 31-34 has two communication lines and two power lines. The serial communication buses 31-34 and the serial transfer circuit 55, described later, use, for example, the RS-485 standard.

[0070] As shown in Figure 8, the first vacuum-side sensor module 25 has a rectangular substrate on which an input port 51, an output port 52, an expansion port 53, a signal conversion circuit 54, a serial transfer circuit 55, and a detection circuit 56 are mounted. The signal conversion circuit 54, the serial transfer circuit 55, and the detection circuit 56 may each be composed of a single integrated circuit or multiple electronic components.

[0071] In this embodiment, the first vacuum-side sensor module 25 includes 16 input ports 51, 4 output ports 52, and 4 expansion ports 53. The output ports 52 and expansion ports 53 are arranged in 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 of the first vacuum-side sensor module 25, opposite to side 25a.

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

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

[0074] The serial communication bus 33, which is connected to the hermetic connector 10 and communicates data with the control device 200, has two communication lines, as described above, and transmits the digital detection data described later using these two communication lines. For this reason, of the pins 11A and 11B of the hermetic connector 10 used to connect to the serial communication bus 33, there are also two data transmission pins used to transmit the digital detection data. The total number of physical sensors provided on the turbomolecular pump 100, namely the vacuum-side thermistors 21-23, the atmospheric-side thermistor 24, and the crystal oscillator 29 (5), is greater than the number of these data transmission pins (2).

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

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

[0077] When the detection circuit 56 includes a resonant circuit, the detection data output from the vacuum-side thermistors 21-23 has a period that varies according to the temperature of the vacuum-side thermistors 21-23. In other words, the temperature detected by the vacuum-side thermistors 21-23 is expressed as a function of the period based on the detection data output from the vacuum-side thermistors 21-23.

[0078] The signal conversion circuit 54 is an analog-to-digital conversion circuit that converts analog signals into digital signals. 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 number of bits by sampling and quantizing the analog signal.

[0079] 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, bit by bit using one or two communication lines. In this embodiment, the serial transfer circuit 55 transmits and receives data using two communication lines provided on the serial communication buses 31 to 34.

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

[0081] Note that in Figure 8, to avoid complexity, only one detection circuit 56 is shown for the first vacuum-side sensor module 25, but it is not limited to this, and may have multiple detection circuits 56. In this case, the first vacuum-side sensor module 25 may have detection circuits 56 according to the type of analog signal output from each of the multiple vacuum-side thermistors 21 to 23. Alternatively, instead of having multiple detection circuits 56 only in the first vacuum-side sensor module 25, the multiple detection circuits 56 may be distributed among the first vacuum-side sensor module 25 to the third vacuum-side sensor module 27.

[0082] As shown in Figure 9, the second vacuum-side sensor module 26 (second circuit board) has a detection circuit 57 mounted in place of the detection circuit 56, and apart from these, it has the same configuration as the first vacuum-side sensor module 25. Each detection circuit 57 may be composed of a single integrated circuit or of multiple 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 the type of analog signal, different from that of the detection circuit 56. Similar to the 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 lines of the serial communication bus 32 and the third vacuum-side sensor module 27. A voltage is applied to the crystal oscillator 29 from the detection circuit 57. The crystal oscillator 29 is equipped with a crystal resonator and oscillates with a period corresponding to the 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 period based on the detection data output from the crystal oscillator 29. As a result, the detection circuit 57 can obtain detection data of the 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 containing the digital detection data detected by the detection circuit 57 is output from the output port 52 and sent 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 sensor module 28 has the same configuration as the first vacuum sensor module 25 and is located outside the turbomolecular pump 100. The atmospheric sensor module 28 is located, for example, outside the base portion 129.

[0086] The input port 51 of the atmospheric sensor module 28 is electrically connected to both ends of the atmospheric thermistor 24. The expansion port 53 of the atmospheric sensor module 28 is electrically connected to pins 11A and 11B of the hermetic connector 10, and the output port 52 is electrically connected to the serial communication bus 34 (see Figure 6).

[0087] The detection circuit 56 of the atmospheric sensor module 28 can obtain detection data (analog signal) output from one end of the atmospheric 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, the effects of this embodiment, configured in this way, will be described.

[0089] The turbomolecular pump 100 of this embodiment detects detection data from analog signals output from each of the multiple physical sensors (vacuum-side thermistors 21-23, atmospheric-side thermistor 24, and crystal oscillator 29), converts the analog detection data into digital detection data, and outputs a serial signal including the digital detection data to the control device 200 via serial communication buses 33 and 34. This reduces the number of pins used for data transmission. Furthermore, since the turbomolecular pump 100 is equipped with a signal conversion circuit 54 and a detection circuit 57, it can accommodate an increase in the number or types of physical sensors, and there is no need to increase the detection circuit on the control device 200 side. In other words, the turbomolecular pump 100 has high expandability.

[0090] Furthermore, the first vacuum-side sensor module 25 is provided with an expansion port 53 and an output port 52, and the second vacuum-side sensor module 26, which constitutes the detection circuit 57, and the first vacuum-side sensor module 25 are connected via the expansion port 53. Therefore, if it is desired to increase the number or type of physical sensors, this can be accommodated by newly connecting the second vacuum-side sensor module 26 and the third vacuum-side sensor module 27, thus providing high expandability.

[0091] Furthermore, since the detection circuit 57 is provided according to the type of analog signal output from each of the multiple physical sensors, it is possible to detect detection data from each sensor even if the number or type of physical sensors is increased, thus providing high expandability.

[0092] Furthermore, the first vacuum-side sensor module 25 has a rectangular shape, with an output port 52 and an expansion port 53 located on one side 25a, and an input port 51 located on the other side 25b opposite to side 25a. This separates the side for connecting the physical sensor from the side for connecting the serial communication bus 31 and other communication devices, making wiring easier.

[0093] Since the number of physical sensors (5) provided on the turbomolecular pump 100 is greater than the number of data transmission pins (2) used for transmitting digital detection data among the pins 11A and 11B used to connect the hermetic connector 10 to the serial communication bus 33, the number of pins 11A and 11B used for data transmission can be reduced.

[0094] (Variation 1) Next, the configuration of the turbomolecular pump 100 according to Modification 1 will be described. Figure 10 is a block diagram of the turbomolecular pump 100 according to Modification 1.

[0095] As shown in Figure 10, the turbomolecular pump 100 according to Modification 1 comprises a relay board 41 and a serial communication bus 42. The other configurations are basically the same as those of the turbomolecular pump 100 of the above embodiment shown in Figure 6. The relay board 41 constitutes part of the hermetic connector 10 and is electrically connected to pins 11A and 11B of the hermetic connector 10. A connector (not shown) that connects to the serial communication bus 42 is mounted on the relay board 41. The atmospheric 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 sensor module 28.

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

[0097] The detection circuit 56 of the atmospheric sensor module 28 can obtain detection data (analog signal) output from one end of the atmospheric thermistor 24, similar to the embodiment described above. 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 sent 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 turbomolecular pump 100 of the modified example 1 configured in this way, data transmission and reception with the control device 200 can be performed solely via the serial communication bus 33. The number of cables connecting to the control device 200 is reduced, and the same effects as the above embodiment can be obtained with a simpler configuration.

[0099] (Modification 2) Next, the configuration of the turbomolecular pump 100 according to Modification 2 will be described. Figure 11 is a block diagram of the turbomolecular pump 100 according to Modification 2.

[0100] As shown in Figure 11, the turbomolecular pump 100 according to Modification 2 is equipped with an atmospheric thermistor 43. The other configurations are basically the same as those of the turbomolecular pump 100 of Modification 1 shown in Figure 10. The atmospheric thermistor 43 is located in a different position from the atmospheric thermistor 24 and is located outside the turbomolecular pump 100, for example, on the outer circumferential surface of the outer cylinder 127 or on the bottom surface of the base portion 129.

[0101] In this modified example 2, the relay board 41 is equipped with an input port 51, and both ends of the atmospheric thermistor 43 are electrically connected. Furthermore, in modified example 2, a signal conversion circuit 54 and a detection circuit 56 are mounted on the relay board 41. In this case, the detection circuit 56 of the relay board 41 detects detection data from the analog signal output from the atmospheric 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 modified example 2 turbomolecular pump 100 configured in this way, a detection circuit 56 is provided on the relay board 41. Therefore, even if an atmospheric thermistor 43 is added in addition to the configuration of modified example 1, there is no need to add a sensor module, serial communication bus, etc. In addition to the same effects as the above embodiment, it is also possible to easily accommodate design changes such as adding an atmospheric thermistor 43.

[0103] (Variation 3) Next, the configuration of the turbomolecular pump 100 according to Modification 3 will be described. Figure 12 is a block diagram of the turbomolecular pump 100 according to Modification 3.

[0104] As shown in Figure 12, in the modified example 3, the turbomolecular pump 100 has a serial communication bus 33 for data communication with the control device 200 connected to the relay board 41 instead of pins 11A and 11B of the hermetic connector 10. The rest of the configuration is basically the same as the turbomolecular pump 100 of modified example 2 shown in Figure 11.

[0105] In this modified example 3, the relay board 41 is equipped with a connector that connects to the serial communication bus 42 and an output port, to which the serial communication bus 33 is electrically connected. Similar to modified example 1, the relay board 41 is electrically connected to pins 11A and 11B of the hermetic connector 10, and the atmospheric sensor module 28 is electrically connected 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 sensor module 28.

[0106] The serial signal, which includes 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 pins 11A and 11B 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] Furthermore, the relay board 41 has connection terminals that connect to pins 11A and 11B of the hermetic connector 10. In this way, the relay board 41 converts the connection via pins 11A and 11B to a connection between the output port and the serial communication bus 33 (another connection configuration).

[0108] Furthermore, the detection circuit 56 of the atmospheric sensor module 28 can obtain detection data (analog signal) output from one end of the atmospheric thermistor 24, similar to the embodiment described above. 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 sent to the control device 200 via the serial communication bus 42, the relay board 41, and the serial communication bus 33.

[0109] In the modified example 3 turbomolecular pump 100 configured in this way, the serial communication bus 33 is connected to the relay board 41, and data transmission and reception with the control device 200 can be performed solely through the serial communication bus 33. As a result, the number of cables connecting to the control device 200 is reduced, and the same effects as the above embodiment can be obtained with a simpler configuration.

[0110] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. All technical matters included in the technical concept described in the claims are subject to the present invention. The embodiments described above are preferred examples, but those skilled in the art can realize various alternative examples, modifications, variations, combinations, or improvements from the contents disclosed herein, and these are included in the technical scope described in the appended claims.

[0111] For example, the physical sensors provided in the turbomolecular pump 100 are not limited to thermistors and crystal oscillators; they could also be position sensors for detecting position, rotation sensors for detecting rotation angle, etc.

[0112] Furthermore, the shape of the connector base of the hermetic connector is not limited to the round frame shape described above; any shape of connector base can be used, such as a horizontally elongated rectangular frame. Also, the shape of the connector base may be box-shaped instead of frame-shaped. [Explanation of Symbols]

[0113] 10 Hermetic Connectors 11A Small diameter pin (pin) 11B Large diameter pin (pin) 21-23 Vacuum-side thermistor 24,43 Atmospheric thermistor 25. First vacuum side sensor module (first circuit board) 26. Second vacuum side sensor module (second circuit board) 27. Third vacuum side sensor module 28,44 Atmospheric side sensor module 29 Crystal oscillator 31-34, 42 Serial communication bus 41 Relay board 51 Input Ports 52 output ports 53 Expansion Ports 54 Signal conversion circuit 55 Serial Transfer Circuit 56 Detection Circuit 57 Detection Circuit 100 Turbomolecular Pumps (Vacuum Pumps)

Claims

1. A pump body that performs gas intake and exhaust, Multiple physical sensors provided on the pump body, A vacuum pump equipped with a connector used for connecting to an external device, The aforementioned vacuum pump is A detection circuit that detects detection data from analog signals output from each of the aforementioned multiple physical sensors, A signal conversion circuit that converts the aforementioned detection data into digital detection data as a digital signal, It includes a serial communication bus for performing data communication with the external device via the connector, The vacuum pump is characterized in that the serial communication bus outputs a serial signal including the digital detection data.

2. The first circuit board constituting the signal conversion circuit, The system includes a second circuit board that has an input port into which the aforementioned analog signal is input and constitutes the detection circuit, The first circuit board is, An expansion port connected to the second circuit board, The vacuum pump according to claim 1, characterized by having an output port for outputting the aforementioned digital detection data.

3. The vacuum pump according to claim 2, characterized in that the detection circuit is provided according to the type of analog signal output from each of the plurality of physical sensors.

4. The first circuit board has a rectangular shape, The output port and the expansion port are arranged on one side of the first circuit board. The vacuum pump according to claim 2, characterized in that the input port is located on the other side of the first circuit board facing the one side.

5. The vacuum pump according to any one of claims 1 to 4, characterized in that the number of physical sensors provided on the pump body is greater than the number of data transmission pins used for transmitting the digital detection data among the pins of the connector used for connecting to the serial communication bus.

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

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