Vacuum pump

Abstract

To provide a vacuum pump having an excellent allowable flow rate while suppressing deposition of precipitates.SOLUTION: A vacuum pump is provided with a rotor and a plurality of stator parts having a gas compression function disposed so as to face the rotor, and further, a reference member 301, which is one of members laminated from a base part 129 toward a suction port 101 side, is provided as a reference for the axial positions of the plurality of stator parts. Then, a plurality of stator parts are arranged downstream of the reference member 301 (exhaust port 133 side).SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] In one vacuum pump, the stator of the groove pump section and the fixed vanes (stators) of the turbo molecular pump section are stacked in order along the axial direction toward the intake side with the base section as a reference. In another vacuum pump, the base section extends to the outer peripheral side surface and is cooled by a cooling pipe (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-51952 A Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, in a multi-stage configuration having a plurality of pump sections connected in series, such as the turbomolecular pump section and the thread groove pump section described above, the pressure in the pump section at the latter stage (the thread groove pump section in the vacuum pump described above) becomes high, so it is preferable to increase the temperature of the pump section at the latter stage to suppress deposition of gas deposits, etc. However, if the temperature of the pump section at the latter stage becomes excessive, it will hinder heat dissipation from the pump section at the former stage (the rotor of the turbomolecular pump section), and the allowable gas flow rate will decrease.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide a vacuum pump that has a good allowable flow rate while suppressing the accumulation of deposits. [Means for solving the problem]

[0006] The vacuum pump of the present invention is a vacuum pump having a casing with an intake port, a base portion, a rotor rotatably held within the casing, a plurality of stator portions having a gas compression function arranged opposite the rotor, and a reference member which is one of the members stacked from the base portion toward the intake port side and serves as a reference for the axial direction of the stator portions, and at least two of the plurality of stator portions are arranged downstream of the reference member. Furthermore, the actuator has at least the following configuration (A) or (B): (A) Heat from the heating means flows into at least two of the multiple stator parts that are disposed downstream of the reference member, and (B) the actuator further includes a bolt that is fixed to the base part and presses the stator parts toward the reference member. Effect of the Invention

[0007] According to the present invention, a vacuum pump having a good allowable flow rate while suppressing the accumulation of deposits can be obtained.

[0008] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a vertical sectional view showing a turbomolecular pump as a vacuum pump according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a circuit diagram showing an amplifier circuit that controls excitation of the electromagnets of the turbo molecular pump shown in FIG. [Diagram 3] FIG. 3 is a time chart showing the control when the current command value is larger than the detection value. [Figure 4] FIG. 4 is a time chart showing the control when the current command value is smaller than the detection value. [Diagram 5] FIG. 5 is a cross-sectional view illustrating a reference member and a member positioned by the reference member in the vacuum pump shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view illustrating a configuration around the gap in the vacuum pump according to the first embodiment. [Figure 7]FIG. 7 is a cross-sectional view illustrating an example of fastening a reference member and a member positioned by the reference member in the vacuum pump shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view illustrating another example of fastening the reference member and the member positioned by the reference member in the vacuum pump shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view illustrating a configuration around a gap in a vacuum pump according to the second embodiment. [Figure 10] FIG. 10 is a cross-sectional view illustrating a configuration around a gap in a vacuum pump according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] Embodiment 1

[0012] A longitudinal cross-sectional view of this turbomolecular pump 100 is shown in Fig. 1. In Fig. 1, the turbomolecular pump 100 has an intake port 101 formed at the upper end of a cylindrical outer tube 127. Inside the outer tube 127, a rotor 103 is provided, the rotor 103 having a plurality of rotors 102 (102a, 102b, 102c, ...) which are turbine blades for sucking in and exhausting gas, formed radially on its periphery in multiple stages. A rotor shaft 113 is attached to the center of the rotor 103, and the rotor shaft 113 is supported in the air and position-controlled by, for example, a five-axis controlled magnetic bearing. The rotor 103 is generally made of a metal such as aluminum or an aluminum alloy.

[0013] The upper radial electromagnets 104 are arranged in pairs on the X-axis and the Y-axis. Four upper radial sensors 107 are provided adjacent to the upper radial electromagnets 104 and corresponding to each of the upper radial electromagnets 104. The upper radial sensors 107 are, for example, inductance sensors or eddy current sensors having conductive windings, and detect the position of the rotor shaft 113 based on the change in inductance of the conductive windings that changes according to the position of the rotor shaft 113. The upper radial sensors 107 are configured to detect the radial displacement of the rotor shaft 113, i.e., the rotating body 103 fixed thereto, and send the detected displacement to the control device 200.

[0014] 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 a position signal detected by the upper radial sensor 107, and an 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.

[0015] The rotor shaft 113 is made of a material with high magnetic permeability (iron, stainless steel, etc.) and is attracted by the magnetic force of the upper radial electromagnet 104. Such adjustment is performed independently in the X-axis direction and the Y-axis direction. The lower radial electromagnet 105 and the lower radial sensor 108 are arranged in the same manner as the upper radial electromagnet 104 and the upper radial sensor 107, and adjust the lower radial position of the rotor shaft 113 in the same manner as the upper radial position.

[0016] Furthermore, axial electromagnets 106A and 106B are arranged above and below a circular metal disk 111 provided at the bottom of rotor shaft 113. Metal disk 111 is made of a high magnetic permeability material such as iron. An axial sensor 109 is provided to detect the axial displacement of rotor shaft 113, and an axial position signal is sent to control device 200.

[0017] In the control device 200, a compensation circuit having, for example, a PID adjustment function generates an excitation control command signal for each of the axial electromagnets 106A and 106B based on the axial position signal detected by the axial sensor 109, and the amplifier circuit 150 controls the excitation of 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 by magnetic force and the axial electromagnet 106B attracts the metal disk 111 downward, thereby adjusting the axial position of the rotor shaft 113.

[0018] In this way, the control device 200 appropriately adjusts the magnetic force that the axial electromagnets 106A, 106B exert on the metal disk 111, magnetically levitating the rotor shaft 113 in the axial direction and holding it in a non-contact manner in space. The amplifier circuit 150 that controls the excitation of the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A, 106B will be described later.

[0019] Meanwhile, motor 121 has a plurality of magnetic poles arranged circumferentially so as to surround rotor shaft 113. Each magnetic pole is controlled by control device 200 so as to rotate rotor shaft 113 via electromagnetic force acting between the magnetic pole and rotor shaft 113. Also, motor 121 incorporates a rotation speed sensor such as a Hall element, resolver, or encoder (not shown), and the rotation speed of rotor shaft 113 is detected by a detection signal from this rotation speed sensor.

[0020] 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 detects the position of the magnetic poles using the detection signals of both this phase sensor and the rotation speed sensor.

[0021] A plurality of fixed blades 123 (123a, 123b, 123c...) are arranged with a small gap between the rotor blades 102 (102a, 102b, 102c...). The rotor blades 102 (102a, 102b, 102c...) are formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transport exhaust gas molecules downward through collision. The fixed blades 123 (123a, 123b, 123c...) are made of metal such as aluminum, iron, stainless steel, copper, or an alloy containing these metals as components.

[0022] Similarly, the fixed blades 123 are formed at an inclination at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged alternately with the stages of the rotor blades 102 toward the inside of the outer cylinder 127. The outer peripheral ends of the fixed blades 123 are supported in a state where they are inserted between a plurality of stacked stages of fixed blade spacers 125 (125a, 125b, 125c, etc.).

[0023] The fixed wing spacer 125 is a ring-shaped member and is made of metal such as aluminum, iron, stainless steel, copper, or an alloy containing these metals as components. An outer cylinder 127, a reference member 301, and an outer cylinder member 302 are fixed to the outer periphery of the fixed wing spacer 125 with a gap therebetween. A base portion 129 is disposed at the bottom of the outer cylinder member 302. An exhaust port 133 is disposed above 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 transferred is sent to the exhaust port 133.

[0024] Furthermore, depending on the application of the turbo molecular pump 100, a threaded spacer 131 is disposed between the lower part of the fixed vane spacer 125 and the base part 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 a plurality of helical thread grooves 131a engraved on its inner peripheral surface. The helical direction of the thread groove 131a is the direction in which, when the molecules of the exhaust gas move in the rotation direction of the rotor 103, the molecules are transferred toward the exhaust port 133. A cylindrical part 102d hangs down from the lowest part of the rotor 103, which is connected to the rotor vanes 102 (102a, 102b, 102c, etc.). The outer peripheral surface of this cylindrical part 102d is cylindrical and protrudes toward the inner peripheral surface of the threaded spacer 131, and is adjacent to the inner peripheral surface of the threaded spacer 131 with a predetermined gap therebetween. The exhaust gas transferred to the thread groove 131a by the rotor 102 and the fixed blade 123 is sent to the base portion 129 while being guided by the thread groove 131a.

[0025] The base portion 129 is a disk-shaped member that constitutes the base of the turbomolecular pump 100, and is generally made of metal such as iron, aluminum, stainless steel, etc. The base portion 129 physically holds the turbomolecular pump 100 and also functions as a heat conduction path, so it is desirable to use a metal that has rigidity and high thermal conductivity, such as iron, aluminum, or copper.

[0026] In this configuration, when the rotor 102 is rotated together with the rotor shaft 113 by the motor 121, the exhaust gas is sucked from the chamber through the intake port 101 by the action of the rotor 102 and the fixed blade 123. The rotation speed of the rotor 102 is usually 20,000 rpm to 90,000 rpm, and the peripheral speed at the tip of the rotor 102 reaches 200 m / s to 400 m / s. The exhaust gas sucked through the intake port 101 passes between the rotor 102 and the fixed blade 123 and is transferred to the base part 129. At this time, the temperature of the rotor 102 rises due to frictional heat generated when the exhaust gas comes into contact with the rotor 102 and conduction of heat generated by the motor 121, and the like, but this heat is transferred to the fixed blade 123 side by radiation or conduction by gas molecules of the exhaust gas, and the like.

[0027] The fixed blade spacers 125 are joined to each other at their outer peripheries, and transmit heat received by the fixed blades 123 from the rotor blades 102, frictional heat generated when exhaust gas comes into contact with the fixed blades 123, and the like to the outside.

[0028] In the above description, the threaded spacer 131 is disposed on the outer periphery of the cylindrical portion 102d of the rotor 103, and the thread groove 131a is formed on the inner periphery of the threaded spacer 131. However, there are also cases where the thread groove is formed on the outer periphery of the cylindrical portion 102d, and a spacer having a cylindrical inner periphery is disposed around the outer periphery of the cylindrical portion 102d.

[0029] Depending on the application of the turbomolecular pump 100, in order to prevent the gas sucked in from the intake port 101 from entering the electrical equipment section, which is composed of 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, etc., the electrical equipment section may be covered all around with a stator column 122, and the inside of this stator column 122 may be kept at a predetermined pressure by a purge gas.

[0030] In this case, piping (not shown) is provided in the base portion 129, and purge gas is introduced through this piping. The introduced purge gas is sent to the exhaust port 133 through 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 blades 102.

[0031] Here, the turbomolecular pump 100 requires control based on specific parameters (e.g., various characteristics corresponding to the model) that are individually adjusted and identified as a model. In order to store these control parameters, the turbomolecular pump 100 has an electronic circuit section 141 in its main body. The electronic circuit section 141 is composed of a semiconductor memory such as an EEPROM, electronic components such as semiconductor elements for accessing the memory, and a substrate 143 for mounting these components. The electronic circuit section 141 is housed below a rotational speed sensor (not shown) near the center of a base section 129 that constitutes the lower part of the turbomolecular pump 100, and is closed by an airtight bottom cover 145.

[0032] 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 turbo molecular pump 100, the pressure of the exhaust gas is lowest at the intake port 101 and highest at the exhaust port 133. If the pressure of the process gas becomes higher than a predetermined value or the temperature falls below a predetermined value while the process gas is being transferred from the intake port 101 to the exhaust port 133, the process gas becomes solid and adheres to and accumulates inside the turbo molecular pump 100.

[0033] For example, SiCl is used as a process gas in an Al etching device. 4 When low vacuum (760[torr]~10 -2 At low temperatures (approximately 20°C) and at low temperatures (approximately 20°C), solid products (e.g., AlCl 3) precipitates and adheres to and accumulates inside the turbomolecular pump 100. As a result, when precipitates of the process gas accumulate inside the turbomolecular pump 100, the deposits narrow the pump flow path, causing a decrease in the performance of the turbomolecular pump 100. The above-mentioned products are prone to solidification and adhesion in high-pressure areas near the exhaust port 133 and near the threaded spacer 131.

[0034] Therefore, in order to solve this problem, in the past, a heater (not shown) or a circular water-cooled tube 149 was wrapped around the outer periphery of the base portion 129, and a temperature sensor (e.g., a thermistor) (not shown) was embedded in the base portion 129, and the heating of the heater and the cooling by the water-cooled tube 149 were controlled based on the signal from this temperature sensor to keep the temperature of the base portion 129 at a constant high temperature (set temperature) (hereinafter referred to as TMS; Temperature Management System).

[0035] Next, regarding the turbo molecular pump 100 configured as described above, an amplifier circuit 150 that controls excitation of the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A and 106B will be described. A circuit diagram of this amplifier circuit 150 is shown in FIG.

[0036] 2, one end of an electromagnet winding 151 constituting the upper radial electromagnet 104 etc. is connected to a positive electrode 171a of a power source 171 via a transistor 161, and the other end is connected to a negative electrode 171b of the power source 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 drain.

[0037] At this time, the transistor 161 has a cathode terminal 161a of the diode connected to the positive electrode 171a, and an anode terminal 161b connected to one end of the electromagnet winding 151. The transistor 162 has a cathode terminal 162a of the diode connected to the current detection circuit 181, and an anode terminal 162b connected to the negative electrode 171b.

[0038] On the other hand, the current regeneration diode 165 has its cathode terminal 165a connected to one end of the electromagnet winding 151 and its anode terminal 165b connected to the negative electrode 171b. Similarly, the current regeneration diode 166 has its cathode terminal 166a connected to the positive electrode 171a and its anode terminal 166b connected to the other end of the electromagnet winding 151 via a current detection circuit 181. The current detection circuit 181 is composed of, for example, a Hall sensor type current sensor or an electric resistance element.

[0039] The amplifier circuit 150 configured as above corresponds to one electromagnet. Therefore, when the magnetic bearing is controlled by five axes and there are a total of ten electromagnets 104, 105, 106A, and 106B, a similar amplifier circuit 150 is configured for each electromagnet, and the ten amplifier circuits 150 are connected in parallel to the power supply 171.

[0040] Furthermore, the amplifier control circuit 191 is configured, for example, by a digital signal processor section (hereinafter referred to as a DSP section) (not shown) of the control device 200, and this amplifier control circuit 191 switches the transistors 161 and 162 on / off.

[0041] The amplifier control circuit 191 is adapted to compare the current value detected by the current detection circuit 181 (a signal reflecting this current value is called a current detection signal 191c) with a predetermined current command value. Then, based on the result of this comparison, the magnitude of the pulse width (pulse width times Tp1, Tp2) to be generated within a control cycle Ts, which is one period of PWM control, is determined. As a result, gate drive signals 191a, 191b having this pulse width are output from the amplifier control circuit 191 to the gate terminals of the transistors 161, 162.

[0042] In addition, when the rotor 103 passes through a resonance point during an accelerating operation of the rotation speed, or when a disturbance occurs during a constant speed operation, it is necessary to control the position of the rotor 103 at high speed and with a strong force. For this reason, a high voltage of, for example, about 50 V is used as the power supply 171 so that the current flowing through the electromagnet winding 151 can be rapidly increased (or decreased). In addition, a capacitor (not shown) is usually connected between the positive pole 171a and the negative pole 171b of the power supply 171 to stabilize the power supply 171.

[0043] In this configuration, when both transistors 161, 162 are turned on, the current flowing through the electromagnet winding 151 (hereinafter referred to as electromagnet current iL) increases, and when both are turned off, the electromagnet current iL decreases.

[0044] Moreover, when one of the transistors 161, 162 is turned on and the other is turned off, a so-called flywheel current is maintained. By passing a flywheel current 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 kept low. Furthermore, by controlling the transistors 161, 162 in this manner, high-frequency noise such as harmonics generated in the turbo molecular pump 100 can be reduced. Furthermore, by measuring this flywheel current with the current detection circuit 181, the electromagnet current iL flowing through the electromagnet winding 151 can be detected.

[0045] That is, when the detected current value is smaller than the current command value, both of the transistors 161 and 162 are turned on for a time period corresponding to the pulse width time Tp1 only once in a control cycle Ts (e.g., 100 μs) as shown in Fig. 3. Therefore, the electromagnet current iL during this period increases toward a current value iLmax (not shown) that can flow from the positive electrode 171a to the negative electrode 171b via the transistors 161 and 162.

[0046] On the other hand, when the detected current value is larger than the current command value, both of the transistors 161 and 162 are turned off for a time period corresponding to the pulse width time Tp2 only once during the control cycle Ts, as shown in Fig. 4. Therefore, the electromagnet current iL during this period decreases toward a current value iLmin (not shown) that can be regenerated from the negative pole 171b to the positive pole 171a via the diodes 165 and 166.

[0047] In either case, after the pulse width times Tp1 and Tp2 have elapsed, one of the transistors 161 and 162 is turned on. Therefore, a flywheel current is maintained in the amplifier circuit 150 during this period.

[0048] The turbomolecular pump 100 is configured as described above. This turbomolecular pump 100 is an example of a vacuum pump. Furthermore, in FIG. 1, the rotor 102 and the rotor 103 are the rotor of the turbomolecular pump 100, the fixed blade 123 and the fixed blade spacer 125 are the stator part of the turbomolecular pump part, and the threaded spacer 131 is the stator part of the thread groove pump part at the rear stage of the turbomolecular pump part. Furthermore, the intake port 101, the exhaust port 133, the outer cylinder 127, the reference member 301, and the outer cylinder member 302 are the casing of the turbomolecular pump 100, and house the rotor and the multiple stator parts. That is, the rotor is rotatably held in the casing, and the multiple stator parts are arranged opposite to the rotor, and have a gas compression function.

[0049] FIG. 5 is a cross-sectional view illustrating the reference member 301 and members positioned by the reference member 301 in the vacuum pump shown in FIG.

[0050] 1, reference member 301 is one of the members (hereinafter referred to as stacked members) stacked from base portion 129 toward intake port 101, and is an annular member that serves as a reference for the axial positions of the above-mentioned multiple stator portions. The above-mentioned multiple stator portions (stator portion of the turbo molecular pump portion, stator portion of the thread groove pump portion, etc.) are disposed on the exhaust port 133 side with respect to reference member 301, and are positioned in the axial direction by reference member 301. Note that these multiple stator portions are not included in the above-mentioned stacked members.

[0051] In this embodiment, as shown in FIG. 5, fixed vane 123d and fixed vane spacer 125d (i.e., the stator portion of the turbomolecular pump portion (part)) and threaded spacer 131 (i.e., the stator portion of the threaded pump portion) are axially positioned by reference member 301 on the exhaust side relative to reference member 301.

[0052] Specifically, one end of the stator portion formed by the fixed wing 123d and the fixed wing spacer 125d contacts the reference member 301 along the axial direction, and one end of the threaded spacer 131 contacts the other end of the stator portion formed by the fixed wing 123d and the fixed wing spacer 125d along the axial direction. Also, one end of the annular member 303 contacts the reference member 301, and the other end of the annular member 303 contacts the threaded spacer 131. Furthermore, the other end of the threaded spacer 131 does not contact the base portion 129, and a gap 311 is formed between the threaded spacer 131 and the base portion 129.

[0053] In this way, the fixed wing 123d and the fixed wing spacer 125d (i.e., the stator portion of the turbomolecular pump portion (part)) and the threaded spacer 131 (i.e., the stator portion of the threaded pump portion) are not positioned by the base portion 129, but by the reference member 301.

[0054] Furthermore, the threaded spacer 131 is provided with a heater 304, and the reference member 301 is provided with a cooling pipe 305. Therefore, heat flowing from the heater 304 into the threaded spacer 131 flows from the threaded spacer 131 through the fixed vanes 123d and the fixed vane spacer 125d (i.e., the stator portion of the turbo molecular pump portion (part)) and the annular member 303 into the reference member 301. As a result, the temperature in the gas flow path gradually decreases in the order of the threaded spacer 131, the stator portion formed by the fixed vanes 123d and the fixed vane spacer 125d, and the reference member 301.

[0055] Fig. 6 is a cross-sectional view illustrating a configuration around gap 311 in the vacuum pump according to embodiment 1. In embodiment 1, as shown in Fig. 6, a heat insulating member 321 and an elastic member 322 are disposed in gap 311.

[0056] The heat insulating member 321 is an annular member having a thermal conductivity lower than that of the threaded spacer 131 and the base portion 129, and has a flange portion 321a. The flange portion 321a has a plurality of holes along the circumferential direction, and bolts 323 passing through the holes are screwed to the base portion 129, whereby the heat insulating member 321 is fixed to the base portion 129.

[0057] In this embodiment, for example, the threaded spacer 131 and the base portion 129 are made of aluminum, and the heat insulating member 321 is made of stainless steel.

[0058] Furthermore, the outer peripheral surface of the heat insulating member 321 contacts the inner wall surface of the threaded spacer 131 to position the threaded spacer 131 in the radial direction. Compared to when the vacuum pump is stopped, when the vacuum pump is operating, the threaded spacer 131 has a higher temperature than the base portion 129 and the heat insulating member 321, and therefore the threaded spacer 131 experiences greater thermal expansion. Therefore, by bringing the heat insulating member 321 into contact with the inner wall surface of the threaded spacer 131 to position it in the radial direction in this manner, the heat insulating effect is increased.

[0059] FIG. 7 is a cross-sectional view illustrating an example of fastening of the reference member 301 and a member positioned by the reference member 301 in the vacuum pump shown in FIG.

[0060] In the first embodiment, as shown in Fig. 7, for example, the fixed vanes 123d and the fixed vane spacer 125d (i.e., the stator portion of the turbo molecular pump portion (part)) and the threaded spacer 131 (i.e., the stator portion of the thread groove pump portion) are fixed to the reference member 301 by bolts 401, 402. Note that, although one bolt 401, 402 is shown in Fig. 7, a plurality of bolts 401, 402 are provided at predetermined intervals in the circumferential direction.

[0061] Specifically, the annular member 303 is directly fixed to the reference member 301 by bolt 401, and the threaded spacer 131 is directly fixed to the annular member 303 by bolt 402, and the fixed vane 123d and the fixed vane spacer 125d (i.e., the stator portion of the turbomolecular pump portion (part)) are fixed to the reference member 301 so as to be sandwiched between the reference member 301 and the threaded spacer 131.

[0062] Fig. 8 is a cross-sectional view for explaining another example of fastening of reference member 301 and a member positioned by reference member 301 in the vacuum pump shown in Fig. 1. In Fig. 7, bolt 401 is inserted into a hole in reference member 301 and threadedly coupled to bolt 401 and annular member 303, but instead, for example, as shown in Fig. 8, bolt 403 may be inserted into a hole in annular member 303 and threadedly coupled to reference member 301 by bolt 403.

[0063] 6, the elastic member 322 is a member that expands and contracts in the axial direction, and here, one end of the elastic member 322 contacts the threaded spacer 131, and the other end of the elastic member 322 contacts the heat insulating member 321. Note that when the heat insulating member 321 is omitted, the other end of the elastic member 322 contacts the base portion 129.

[0064] In the first embodiment, the elastic member 322 is an O-ring.

[0065] At least one of the reference member 301 and the outer tubular member 302 is provided with a temperature sensor (not shown), and the control device 200 uses the temperature sensor to measure the temperature at the temperature sensor installation position, and adjusts the heat generation amount of the heater 304 and / or the flow rate of the coolant (water in this case) in the cooling pipe 305 based on the measured temperature to control the temperature of one or both of the reference member 301 and the outer tubular member 302 to a predetermined temperature. As a result, at least one of the reference member 301 and the outer tubular member 302 serves as a low-temperature source, and temperature changes in the outer tubular member 302 (and the reference member 301) during operation are suppressed, thereby suppressing thermal expansion of the outer tubular member 302 (and the reference member 301), and preventing a decrease in the accuracy of the axial position of each part such as the above-mentioned laminated members.

[0066] Next, the operation of the vacuum pump according to the first embodiment will be described.

[0067] When the vacuum pump is in operation, motor 121 operates and the rotor rotates under the control of control device 200. As a result, gas flowing in through intake port 101 is transported along the gas flow path between the rotor and the stator, and is discharged from exhaust port 133 to an external piping.

[0068] When the vacuum pump is in operation, the control device 200 controls the temperature by controlling the flow rate of the refrigerant in the heater 304 and the cooling pipe 305. At that time, heat flows from the threaded spacer 131 on which the heater 304 is installed to the reference member 301 via the fixed vanes 123d, the fixed vane spacer 125d, and the annular member 303.

[0069] Therefore, the temperature distribution along the flow path is appropriately set. In other words, the temperature gradually increases toward the exhaust side where the pressure is higher, so that unnecessary heating by the heater 304 can be suppressed while a temperature necessary for suppressing deposition is secured at each flow path position.

[0070] As described above, according to the first embodiment, in the vacuum pump, the reference member 301 is one of the members stacked from the base portion 129 toward the intake port 101 side, and is an annular member that serves as a reference for the axial position of a plurality of stator portions (fixed vanes 123d and fixed vane spacer 125d (i.e., the stator portion of the turbo molecular pump portion) and threaded spacer 131 (i.e., the stator portion of the thread groove pump portion)) having a gas compression function. The plurality of stator portions are disposed downstream of the reference member 301 (on the exhaust port 133 side).

[0071] This makes it easy to adjust the temperature distribution in the flow path to an appropriate temperature distribution, and allows for appropriate heat dissipation (cooling) of the front-stage pump section (here, the turbomolecular pump section) and heating of the rear-stage pump section (here, the thread groove pump section), thereby achieving a good allowable flow rate while suppressing the accumulation of precipitates.

[0072] Embodiment 2

[0073] FIG. 9 is a cross-sectional view illustrating the configuration around gap 311 in the vacuum pump according to the second embodiment.

[0074] In the second embodiment, as shown in Fig. 9, an elastic member 501 is used instead of the above-mentioned elastic member 322 (O-ring). The elastic member 501 is a spring. A plurality of elastic members 501 are provided at predetermined intervals along the circumferential direction.

[0075] Other configurations and operations of the vacuum pump according to the second embodiment are similar to those of the first embodiment, so the description thereof will be omitted.

[0076] Embodiment 3

[0077] FIG. 10 is a cross-sectional view illustrating the configuration around gap 311 in the vacuum pump according to the third embodiment.

[0078] In the third embodiment, base portion 129 is formed with hole 601 along the axial direction, and hole 601 is formed with female thread 601a corresponding to the male thread of bolt 602. The male thread and female thread 601a of bolt 602 are screwed together, and by rotating bolt 602, tip flat surface 602a of bolt 602 advances or retreats along the axial direction, whereby tip flat surface 602 of bolt 602 contacts the bottom surface of threaded spacer 131.

[0079] In this way, the bolt 602 is fixed to the base portion 129, and the tip flat surface 602a of the bolt 602 presses the threaded spacer 131 toward the reference member 301. As a result, the threaded spacer 131 is pressed against the stator portion (the fixed vanes 123d and the fixed vane spacer 125d) of the turbo molecular pump and the annular member 303, and the stator portion (the fixed vanes 123d and the fixed vane spacer 125d) of the turbo molecular pump and the annular member 303 are pressed against the reference member 301.

[0080] As a result, the stator portion (stationary vanes 123d and stationary vane spacer 125d) of the turbo molecular pump is brought into contact with and fixed to the reference member 301, and the stator portion (stationary vanes 123d and stationary vane spacer 125d) of the turbo molecular pump and the threaded spacer 131 are pressed against each other until the threaded spacer 131 is brought into contact with and fixed to the stator portion (stationary vanes 123d and stationary vane spacer 125d) of the turbo molecular pump, and the stator portion (stationary vanes 123d and stationary vane spacer 125d) of the turbo molecular pump and the threaded spacer 131 are positioned by the reference member 301. Therefore, in the third embodiment, the above-mentioned bolts 401, 402, 403 do not need to be provided. Note that a plurality of bolts 602 (and holes 601) are provided at predetermined intervals along the circumferential direction at positions that do not interfere with the above-mentioned bolts 323.

[0081] Other configurations and operations of the vacuum pump according to embodiment 3 are similar to those of embodiment 1 or 2, so description thereof will be omitted.

[0082] It should be noted that various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. In other words, such changes and modifications are intended to be included within the scope of the claims.

[0083] For example, in the above-mentioned first, second and third embodiments, the above-mentioned multiple stator parts are different types of stator parts and include at least two types of stator parts among a turbomolecular pump, a Holweck pump (thread groove pump) and a Sigburn pump. That is, in the above-mentioned first, second and third embodiments, a Sigburn pump may be added, or a Sigburn pump may be used instead of the turbomolecular pump or the Holweck pump (thread groove pump). Also, instead of any of the turbomolecular pump, the Holweck pump (thread groove pump) and the Sigburn pump, a pump of another type (for example, a pump in which a perforated disk and a spiral blade are rotated relatively as described in International Publication WO2013 / 110936) may be used, or a pump of another type may be added.

[0084] In addition, in the above-mentioned embodiments 1, 2 and 3, the cooling pipe 305 is provided in the reference member 301, but instead, the cooling pipe 305 (and the above-mentioned temperature sensor) may be provided in the outer cylinder 302 connected to the reference member 301.

[0085] In addition, in the above-mentioned first, second and third embodiments, the reference member 301 is connected to the base portion 129 via the outer cylinder 302 as described above, but the outer cylinder 302 may not be provided, and the reference member 301 may be one member including the shape of the outer cylinder 302, directly connected to the base portion 129 and similarly temperature-controlled. In other words, the reference member 301 may be directly connected to the base portion 129 and temperature-controlled. [Industrial Applicability]

[0086] The present invention is applicable to, for example, a vacuum pump. [Explanation of symbols]

[0087] 100 Turbo molecular pump (an example of a vacuum pump) 123d Fixed blade (part of an example of a stator section) 125d Fixed blade spacer (part of an example of a stator section) 129 Base 131 Threaded spacer (an example of a stator part) 301 Reference Material 302 External cylinder member 321 Insulation materials 322,501 Elastic members 602 Volts

Claims

1. A vacuum pump comprising: a casing having an intake port; a base portion; a rotor rotatably held within the casing; a plurality of stator portions having a gas compression function and disposed opposite the rotor; and a reference member which is one of members stacked from the base portion toward the intake port side and serves as a reference for the stator portion in an axial direction, At least two of the stator portions are disposed downstream of the reference member, Heat from a heating means flows into at least two of the stator portions that are disposed downstream of the reference member among the plurality of stator portions; A vacuum pump characterized by:

2. 2. The vacuum pump according to claim 1, wherein the plurality of stator portions are different types of stator portions and include at least two types of stator portions selected from the group consisting of a turbomolecular pump, a Holweck pump, and a Sigburn pump.

3. 2. The vacuum pump of claim 1, further comprising a gap between said stator portion and said base portion.

4. 4. The vacuum pump according to claim 3, further comprising a heat insulating member in said gap.

5. 5. The vacuum pump according to claim 4, wherein the heat insulating member contacts an inner wall surface of the stator portion to position the stator portion in the radial direction.

6. 2. The vacuum pump according to claim 1, wherein the stator portion is fixed to the reference member by using a bolt.

7. 4. The vacuum pump according to claim 3, further comprising an elastic member in the gap.

8. 8. The vacuum pump according to claim 7, wherein the elastic member is an O-ring.

9. A vacuum pump having a casing with an intake port, a base portion, a rotor rotatably held within the casing, a plurality of stator portions having a gas compression function arranged opposite the rotor, and a reference member which is one of the members stacked from the base portion toward the intake port side and serves as a reference for the axial direction of the stator portion, At least two of the plurality of stator portions are disposed downstream of the reference member, The vacuum pump further comprises a bolt fixed to the base portion and pressing the stator portion toward the reference member.

10. An outer cylinder member connected to the base portion is further provided. The reference member is connected to the outer cylinder member, At least one of the reference member and the outer cylinder member is temperature controlled; 2. The vacuum pump according to claim 1,

11. 2. The vacuum pump according to claim 1, wherein the reference member is directly connected to the base portion and is temperature controlled.

12. 12. The vacuum pump according to claim 1, wherein heat flows from the stator portion to the reference member.

Images