Vacuum pump

Abstract

To provide a vacuum pump capable of stably controlling the temperature of gas without impairing the cooling effects of the gas.SOLUTION: A vacuum pump (100) includes casings (126, 127), a rotor shaft (113) rotatably supported inside the casing, a plurality of stages of rotary wings (102) fixed to the rotor shaft and rotatable together with the rotor shaft, a plurality of stages of fixed wings (123) fixed to the casing and arranged between the plurality of stages of rotary wings, and a plurality of stages of fixed wing spacers (125) supporting the plurality of fixed wings, and further includes temperature control means (110) provided in the specified spacers (128, 228) out of the plurality of stages of fixed wing spacers for performing temperature control of the specified spacers, and a temperature sensor (185) provided at a position closer to the temperature control means than a gas flow path (F1) of a turbo pump part constituted by the plurality of stages of rotary wings and the plurality of stages of fixed wings.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] As a conventional technique in this technical field, for example, the turbo molecular pump described in Patent Document 1 includes a temperature control unit provided between a casing and a base. This temperature control unit is composed of a temperature control spacer that forms a pump housing together with the casing and the base, and a cooling water pipe, a heater, and a temperature detection unit provided on the temperature control spacer. And according to Patent Document 1, it is said that the temperature controllability of the stator blades on the downstream side of the turbine pump section is improved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the temperature control unit of Patent Document 1, since the cooling water pipe is located close to the gas flow path, the gas temperature is easily affected by the temperature of the cooling water pipe, and there is a problem that the control of the gas temperature is not stable.

[0005] Therefore, an object of the present invention is to provide a vacuum pump capable of stably controlling the gas temperature without impairing the cooling effect of the gas.

Means for Solving the Problems

[0006] To achieve the above object, one aspect of the present invention is a vacuum pump including a casing, a rotor shaft rotatably supported inside the casing, a plurality of stages of rotating blades fixed to the rotor shaft and rotatable together with the rotor shaft, a plurality of stages of stationary blades fixed to the casing and disposed between the plurality of stages of rotating blades, and a plurality of stages of stationary blade spacers supporting the plurality of stages of stationary blades, the vacuum pump including temperature adjusting means provided in a specific spacer which is one stage of the plurality of stages of stationary blade spacers for adjusting the temperature of the specific spacer, and a temperature sensor, wherein a distance between the temperature sensor and a gas flow path of a turbopump section constituted by the temperature sensor, the plurality of stages of rotating blades, and the plurality of stages of stationary blades is longer than a distance between the temperature sensor and the temperature adjusting means, the temperature adjusting means includes a cooling pipe through which a cooling medium flows, and supply and stop of the cooling medium are controlled based on temperature data from the temperature sensor The specific spacer includes a support portion that supports adjacent fixed-wing spacers in the axial direction, and an overhanging portion that protrudes radially outward from the support portion to cover the outer peripheral side of the fixed-wing spacer. The thickness of the overhanging portion is greater than that of the support portion. The temperature sensor and the cooling pipe are embedded in the overhanging portion, and the temperature sensor is provided at a position between the gas flow path and the cooling pipe in the radial direction or outside the cooling pipe in the radial direction. It is characterized by this.

[0007] In the above configuration, the casing includes an outer cylinder disposed on the outer peripheral side of the rotor shaft and a base portion disposed below the outer cylinder, and the specific spacer is made of a member having a higher thermal conductivity than the outer cylinder.

[0008] In the above configuration, the specific spacer is made of an aluminum material.

[0009] In the above configuration, the specific spacer is disposed between the uppermost stage and the lowermost stage of the plurality of stages of stationary blades.

[0010] In the above configuration, the specific spacer The covers the outer peripheral side of the stationary blade spacers adjacent in the axial direction. The It is characterized by this.

[0013] In the above configuration, a fixed component constituting a part of a screw groove pump section is provided on the downstream side of the plurality of stages of rotating blades and the plurality of stages of stationary blades, and the fixed component is heated by heating means.

Effect of the Invention

[0014] According to the vacuum pump of the present invention, the temperature of the gas can be stably controlled without impairing the cooling effect of the gas. In addition, problems, configurations, and effects other than those described above will be clarified by the description of the following embodiments.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the vacuum pump according to the present invention will be described with reference to the drawings, taking a turbo molecular pump as an example.

[0017] (First Embodiment) A longitudinal sectional view of this turbo molecular pump 100 is shown in Fig. 1. In Fig. 1, an intake port 101 is formed at the upper end of a cylindrical outer cylinder 127 of the turbo molecular pump 100. Inside the outer cylinder 127, a rotor 103 is provided with a plurality of rotating blades 102 (102a, 102b, 102c ···), which are turbine blades for sucking and exhausting gas, radially and multi-staged on the circumferential part. A rotor shaft 113 is attached to the center of this rotor 103, and this rotor shaft 113 is levitated and position-controlled in the air by, for example, a magnetic bearing with five-axis control. The rotor 103 is generally composed of a metal such as aluminum or an aluminum alloy, or stainless steel.

[0018] Also, as shown in Fig. 1, a water-cooled spacer 128 and an outer wall 126, which are outer peripheral components, are arranged on the outer peripheral side of the rotor 103. The water-cooled spacer 128 is a ring-shaped member incorporating an annular cooling pipe 110 (see Fig. 5), which is a temperature adjusting means, and a temperature sensor 185. By supplying cooling water to this cooling pipe 110, the components around the water-cooled spacer 128 are cooled. That is, the heat generated by the rotation of the rotor 103 is cooled by the water-cooled spacer 128. The outer wall 126 is a cylindrical member surrounding substantially the lower half of the turbo molecular pump 100. The water-cooled spacer 128 and the outer wall 126 are arranged coaxially with the outer cylinder 127 in order below the outer cylinder 127. These outer cylinder 127, water-cooled spacer 128, and outer wall 126 are fastened and integrated by a plurality of bolts 115, and together with the base portion 129, they constitute the exterior body (casing) of the turbo molecular pump 100 that houses the rotor 103.

[0019] Here, the water-cooled spacer 128 also has a function as a fixed blade spacer 125 described later. That is, the water-cooled spacer 128 (specific spacer) constitutes one (one stage) of the plurality of fixed blade spacers 125. Note that the water-cooled spacer 128 is made of a member with a higher thermal conductivity than the outer cylinder 127 or the outer wall 126, for example, an aluminum material.

[0020] The upper radial electromagnet 104 has four electromagnets arranged in pairs with respect to the X-axis and the Y-axis. Four upper radial sensors 107 are provided in proximity to the upper radial electromagnet 104 and corresponding to each of the upper radial electromagnets 104. The upper radial sensor 107 uses, for example, an inductance sensor having a conductive winding or an eddy current sensor, and detects the position of the rotor shaft 113 based on the change in the inductance of the conductive winding that changes according to the position of the rotor shaft 113. The upper radial sensor 107 is configured to detect the radial displacement of the rotor shaft 113, that is, the rotating body 103 fixed thereto, and send it to the control device 195.

[0021] In this control device 195, 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 FIG. 2 controls the excitation of the upper radial electromagnet 104 based on this excitation control command signal, thereby adjusting the radial position above the rotor shaft 113.

[0022] The rotor shaft 113 is formed of a high magnetic permeability material (such as iron or stainless steel) 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. Further, 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 the radial position below the rotor shaft 113 is adjusted in the same manner as the radial position above.

[0023] Furthermore, axial electromagnets 106A and 106B are arranged sandwiching a disk-shaped metal disk 111 provided at the lower part of the rotor shaft 113 from above and below. The 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 the rotor shaft 113, and its axial position signal is configured to be sent to the control device 195.

[0024] Then, in the control device 195, for example, a compensation circuit having a PID control function generates respective excitation control command signals for the axial electromagnet 106A and the axial electromagnet 106B based on the axial position signal detected by the axial sensor 109. The amplifier circuit 150 performs excitation control on the axial electromagnet 106A and the axial electromagnet 106B respectively based on these excitation control command signals. As a result, the axial electromagnet 106A attracts the metal disk 111 upward by magnetic force, the axial electromagnet 106B attracts the metal disk 111 downward, and the axial position of the rotor shaft 113 is adjusted.

[0025] In this way, the control device 195 appropriately adjusts the magnetic forces exerted by the axial electromagnets 106A and 106B on the metal disk 111, magnetically levitates the rotor shaft 113 in the axial direction, and holds it in space in a non-contact manner. Note that the amplifier circuit 150 for performing excitation control on these upper radial electromagnets 104, lower radial electromagnets 105, and axial electromagnets 106A and 106B will be described later.

[0026] On the other hand, the motor 121 includes a plurality of magnetic poles arranged in a circumferential shape so as to surround the rotor shaft 113. Each magnetic pole is controlled by the control device 195 so as to rotationally drive the rotor shaft 113 via the electromagnetic force acting between the magnetic pole and the rotor shaft 113. In addition, the motor 121 incorporates a rotational speed sensor such as a hall element, a resolver, or an encoder (not shown), and the rotational speed of the rotor shaft 113 is detected by the detection signal of this rotational speed sensor.

[0027] Furthermore, for example, a phase sensor (not shown) is attached near the lower radial sensor 108 to detect the rotation phase of the rotor shaft 113. In the control device 195, the detection signals of this phase sensor and the rotational speed sensor are used together to detect the position of the magnetic pole.

[0028] A plurality of fixed wings 123 (123a, 123b, 123c ···) are arranged with a slight gap from the rotary wings 102 (102a, 102b, 102c ···). A turbo pump section is constituted by these multiple stages of rotary wings 102 and multiple stages of fixed wings 123. The rotary wings 102 (102a, 102b, 102c ···) are each formed by being inclined by a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transfer the molecules of the exhaust gas downward by collision. The fixed wings 123 (123a, 123b, 123c ···) are made of a metal such as aluminum, iron, stainless steel, copper, or an alloy containing these metals as components.

[0029] Also, the fixed wings 123 are similarly formed by being inclined by a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged alternately with the stages of the rotary wings 102 toward the inside of the outer cylinder 127. And the outer peripheral ends of the fixed wings 123 are supported in a state of being inserted between a plurality of stacked fixed wing spacers 125 (125a, 125b, 125c ···).

[0030] The fixed wing spacer 125 is a ring-shaped member and is made of a metal such as aluminum, iron, stainless steel, copper, or an alloy containing these metals as components. The outer cylinder 127 is fixed to the outer periphery of the fixed wing spacer 125 with a slight gap. A base portion 129 is arranged at the bottom of the outer cylinder 127 (more specifically, the bottom of the outer wall 126). An exhaust port 133 is formed above the base portion 129 and communicates with the outside. The exhaust gas that has entered from the intake port 101 from the chamber (vacuum chamber) side and has been transferred toward the base portion 129 is sent to the exhaust port 133.

[0031] Furthermore, depending on the use of the turbo molecular pump 100, a threaded spacer 131 that functions as a screw groove pump section is disposed between the lower part of the fixed wing 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 as components, and a plurality of spiral screw grooves 131a are engraved on its inner peripheral surface. The direction of the spiral of the screw groove 131a is such that when the molecules of the exhaust gas move in the rotation direction of the rotating body 103, these molecules are transferred toward the exhaust port 133. A cylindrical portion 102d hangs down at the lowermost part following the rotating blades 102 (102a, 102b, 102c ···) of the rotating body 103. The outer peripheral surface of this cylindrical portion 102d is cylindrical and protrudes toward the inner peripheral surface of the threaded spacer 131, and is close to the inner peripheral surface of this threaded spacer 131 with a predetermined gap therebetween. The exhaust gas transferred to the screw groove 131a by the rotating blades 102 and the fixed blades 123 is sent to the base section 129 while being guided by the screw groove 131a.

[0032] More specifically, the exhaust gas guided by the screw groove 131a is sent to an annular space 135 formed above the base section 129, and is discharged to the outside through the exhaust port 133 while circulating in the annular space 135. This annular space 135 is an annular space partitioned by the cylindrical portion 102d of the rotating body 103, the threaded spacer 131, the heater spacer 153, and the base section 129.

[0033] Here, the heater spacer 153, which is a fixed component, is a cylindrical member and is integrally formed with the threaded spacer 131 in this embodiment. That is, the heater spacer 153 constitutes a part of the threaded spacer 131. Of course, the heater spacer 153 and the threaded spacer 131 may be separately configured. The heater spacer 153 is made of a metal such as aluminum or stainless steel, for example. A heater 190 as a heating means is inserted into the heater spacer 153, and when the heater 190 generates heat, the threaded spacer 131 is heated via the heater spacer 153. Also, the exhaust gas flowing through the annular space 135 is heated by the heater 190. Thereby, the generation of deposits due to the temperature drop of the exhaust gas is suppressed. Further, the inner spacer 154 is a cylindrical member made of a metal such as stainless steel, for example, and insulates between the water-cooled spacer 128 and the fixed wing spacer 125 below the water-cooled spacer 128.

[0034] The base portion 129 is a disk-shaped member that constitutes the base of the turbo molecular pump 100 and is generally made of a metal such as iron, aluminum, or stainless steel. The base portion 129 physically holds the turbo molecular pump 100 and also serves as a heat conduction path, so it is desirable to use a metal with high rigidity and high thermal conductivity such as iron, aluminum, or copper.

[0035] In such a configuration, when the rotary blade 102 is rotationally driven by the motor 121 together with the rotor shaft 113, the exhaust gas is sucked from the chamber through the intake port 101 by the action of the rotary blade 102 and the fixed blade 123. The rotational speed of the rotary blade 102 is usually 20,000 rpm to 90,000 rpm, and the peripheral speed at the tip of the rotary blade 102 reaches 200 m / s to 400 m / s. The exhaust gas sucked from the intake port 101 passes between the rotary blade 102 and the fixed blade 123 and is transferred to the base portion 129. At this time, the temperature of the rotary blade 102 rises due to the frictional heat generated when the exhaust gas contacts the rotary blade 102 and the conduction of the heat generated by the motor 121, and this heat is transferred to the fixed blade 123 side by radiation or conduction by the gas molecules of the exhaust gas.

[0036] The fixed-wing spacers 125 are joined to each other at their outer peripheral portions, and transfer external heat such as frictional heat generated when the heat or exhaust gas received by the fixed wing 123 from the rotary wing 102 contacts the fixed wing 123.

[0037] In the above description, the threaded spacer 131 is disposed on the outer periphery of the cylindrical portion 102d of the rotating body 103, and the thread groove 131a is engraved on the inner peripheral surface of the threaded spacer 131. However, conversely, there may be a case where a thread groove is engraved on the outer peripheral surface of the cylindrical portion 102d, and a spacer having a cylindrical inner peripheral surface is disposed around it.

[0038] Also, depending on the application of the turbo molecular pump 100, in order to prevent the gas sucked from the intake port 101 from entering the electrical component section 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 component section is covered by the stator column 122 around it, and the inside of this stator column 122 may be maintained at a predetermined pressure with purge gas.

[0039] In this case, a pipe (not shown) is disposed in the base portion 129, and purge gas is introduced through this pipe. 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 the stator of the motor 121, and between the stator column 122 and the inner peripheral cylindrical portion of the rotary wing 102. As shown in FIG. 1, the stator column 122 stands at the central position of the base portion 129. Further, in the present embodiment, a water-cooling pipe 149 as a cooling means is provided in the base portion 129. By supplying cooling water to this water-cooling pipe 149, the base portion 129 and the stator column 122 are maintained at a suitable temperature.

[0040] Here, the turbo molecular pump 100 requires control based on the identification of the model and specific parameters adjusted individually (for example, various characteristics corresponding to the model). To store this control parameter, the turbo molecular pump 100 is provided with an electronic circuit unit 141 inside its body. The electronic circuit unit 141 is composed of semiconductor memories such as EEP-ROM, electronic components such as semiconductor elements for accessing them, and a substrate 143 for mounting them. This electronic circuit unit 141 is housed below a rotation speed sensor (not shown) near the center, for example, of the base unit 129 that constitutes the lower part of the turbo molecular pump 100, and is closed by an airtight bottom cover 145.

[0041] By the way, in the semiconductor manufacturing process, among the process gases introduced into the chamber, there are some that have the property of becoming solid when their pressure becomes higher than a predetermined value or their temperature becomes lower than a predetermined value. Inside the turbo molecular pump 100, the pressure of the exhaust gas is the lowest at the intake port 101 and the highest at the exhaust port 133. When the process gas is transferred from the intake port 101 to the exhaust port 133, if its pressure becomes higher than a predetermined value or its temperature becomes lower than a predetermined value, the process gas becomes solid and adheres and deposits inside the turbo molecular pump 100.

[0042] For example, when SiCl4 is used as the process gas in an Al etching apparatus, it can be seen from the vapor pressure curve that solid products (for example, AlCl3) precipitate and adhere and deposit inside the turbo molecular pump 100 when the pressure is low vacuum (760 [torr] to 10-2 [torr]) and the temperature is low (about 20 [°C]). As a result, when deposits of the process gas accumulate inside the turbo molecular pump 100, this deposit narrows the pump flow path and causes a decrease in the performance of the turbo molecular pump 100. And the above-mentioned products are in a situation where they are likely to solidify and adhere at high-pressure parts near the exhaust port 133 or near the threaded spacer 131.

[0043] Therefore, in order to solve this problem, conventionally, a heater (not shown) or an annular water cooling pipe 149 is wound around the outer periphery of the base portion 129 or the like, and for example, a temperature sensor (for example, a thermistor) not shown is embedded in the base portion 129. Based on the signal of this temperature sensor, heating by the heater and control of cooling by the water cooling pipe 149 (hereinafter referred to as TMS; Temperature Management System) are performed to keep the temperature of the base portion 129 at a certain high temperature (set temperature).

[0044] Next, regarding the turbo molecular pump 100 configured as described above, an amplifier circuit 150 for exciting and controlling the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B will be described. The circuit diagram of this amplifier circuit 150 is shown in FIG. 2.

[0045] In FIG. 2, one end of an electromagnet winding 151 constituting the upper radial electromagnet 104 or the like is connected to the positive electrode 171a of a power supply 171 via a transistor 161, and the other end is connected to the negative electrode 171b of the power supply 171 via a current detection circuit 181 and a transistor 162. The transistors 161 and 162 are so-called power MOSFETs and have a structure in which a diode is connected between their source and drain.

[0046] At this time, for the transistor 161, the cathode terminal 161a of its diode is connected to the positive electrode 171a, and the anode terminal 161b is connected to one end of the electromagnet winding 151. For the transistor 162, the cathode terminal 162a of its diode is connected to the current detection circuit 181, and the anode terminal 162b is connected to the negative electrode 171b.

[0047] On one hand, for the diode 165 for current regeneration, its cathode terminal 165a is connected to one end of the electromagnet winding 151, and its anode terminal 165b is connected to the negative electrode 171b. Similarly, for the diode 166 for current regeneration, its cathode terminal 166a is connected to the positive electrode 171a, and its anode terminal 166b is connected to the other end of the electromagnet winding 151 via the current detection circuit 181. And the current detection circuit 181 is composed of, for example, a Hall sensor type current sensor or an electric resistance element.

[0048] The amplifier circuit 150 configured as above corresponds to one electromagnet. Therefore, when the magnetic bearing is under 5-axis control and there are a total of 10 electromagnets 104, 105, 106A, 106B, similar amplifier circuits 150 are configured for each of the electromagnets, and 10 amplifier circuits 150 are connected in parallel to the power supply 171.

[0049] Furthermore, the amplifier control circuit 191 is composed of, for example, a digital signal processor section (hereinafter referred to as the DSP section) not shown in the control device 195, and this amplifier control circuit 191 is adapted to switch the on / off of the transistors 161 and 162.

[0050] 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 referred to as the current detection signal 191c) with a predetermined current command value. And based on this comparison result, it determines the magnitudes of the pulse widths (pulse width times Tp1, Tp2) to be generated within the control cycle Ts which is one cycle of PWM control. 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 and 162.

[0051] During the acceleration operation of the rotating body 103 when passing through the resonance point or when a disturbance occurs during the constant speed operation, etc., it is necessary to control the position of the rotating body 103 with a high speed and strong force. Therefore, as the power supply 171, a high voltage of about 50V, for example, is used so that a rapid increase (or decrease) in the current flowing through the electromagnet winding 151 can be achieved. Further, a normal capacitor is connected between the positive electrode 171a and the negative electrode 171b of the power supply 171 for stabilizing the power supply 171 (not shown in the figure).

[0052] In such a configuration, when both of the 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.

[0053] Also, when one of the transistors 161 and 162 is turned on and the other is turned off, a so-called flywheel current is held. And by flowing the flywheel current through the amplifier circuit 150 in this way, the hysteresis loss in the amplifier circuit 150 can be reduced, and the power consumption of the entire circuit can be kept low. Further, by controlling the transistors 161 and 162 in this way, 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.

[0054] That is, when the detected current value is smaller than the current command value, as shown in FIG. 3, only once during the control cycle Ts (for example, 100 μs), both of the transistors 161 and 162 are turned on for a time corresponding to the pulse width time Tp1. Therefore, during this period, the electromagnet current iL increases toward the current value iLmax (not shown in the figure) that can flow from the positive electrode 171a to the negative electrode 171b through the transistors 161 and 162.

[0055] On the other hand, when the detected current value is greater than the current command value, as shown in FIG. 4, both transistors 161 and 162 are turned off for only the time corresponding to the pulse width time Tp2 once during the control cycle Ts. Therefore, during this period, the electromagnetic current iL decreases toward the current value iLmin (not shown) that can be regenerated from the negative electrode 171b to the positive electrode 171a via the diodes 165 and 166.

[0056] And in any case, after the elapse of the pulse width times Tp1 and Tp2, one of the transistors 161 and 162 is turned on. Therefore, during this period, the flywheel current is held in the amplifier circuit 150.

[0057] Next, the characteristic part of the turbo molecular pump 100 according to the present embodiment will be described in detail. FIG. 5 is an enlarged view of the main part showing an enlarged view of part A in FIG. 1. As shown in FIG. 5, in the present embodiment, a water-cooled spacer 128 is disposed at a position between the uppermost stage and the lowermost stage among the plurality of stages of stationary blades 123. This water-cooled spacer 128 has a function as a stationary blade spacer 125 that positions the stationary blades 123 in the axial direction, and further plays a role of cooling the stationary blades 123 and reducing the temperature of the rotating blades 102 by radiant heat. As a result, not only the water-cooled spacer 128 but also the gas in contact with the stationary blades 123 is cooled.

[0058] The water-cooled spacer 128 includes the cooling pipe 110 and the temperature sensor 185 as described above. The cooling pipe 110 is provided on the outer peripheral portion of the water-cooled spacer 128. The temperature sensor 185 is provided on the radially inner side of the cooling pipe 110 and in the vicinity of the cooling pipe 110. More specifically, the temperature sensor 185 is provided at a position separated by a distance X1 from the inner peripheral portion (the portion in contact with the gas flow path F1) of the water-cooled spacer 128 and at a position radially inner by a distance Y1 from the cooling pipe 110. And the distance X1 is considerably longer than the distance Y1. That is, the temperature sensor 185 is provided at a position away from the gas flow path F1 and at a position close to the cooling pipe 110.

[0059] Note that the ratio of the distance X1 to the distance Y1 may be arbitrarily determined based on specifications such as the material of the water-cooled spacer 128, the flow rate and temperature of the cooling water flowing through the cooling pipe 110, the flow rate and temperature of the gas flowing through the gas flow path F1, etc. For example, it is preferably set within a range of about 2:1 to 10:1.

[0060] The water-cooled spacer 128 is disposed between the outer cylinder 127 and the outer wall 126 and is fixed by bolts 115. Also, a heat insulating ring 155 is interposed between the water-cooled spacer 128 and the outer wall 126. The heat insulating ring 155 insulates the space between the water-cooled spacer 128 and the outer wall 126. Also, O-rings 192 are mounted between the outer cylinder 127 and the water-cooled spacer 128, and between the inner spacer 154 and the water-cooled spacer 128, and airtightness is maintained.

[0061] Next, the shape of the water-cooled spacer 128 will be described in detail. FIG. 6 is a longitudinal sectional view showing the details of the water-cooled spacer 128 shown in FIG. 5. As shown in FIG. 6, the water-cooled spacer 128 includes a support portion 128a and a projecting portion 128b. The support portion 128a supports the adjacent fixed wing spacers 125 in the axial direction and positions the adjacent fixed wings 123 in the axial direction (vertical direction). The projecting portion 128b is provided to project radially outward from the support portion 128a and has a tapered portion 128b-1 and a body portion 128b-2.

[0062] The tapered portion 128b-1 is inclined so as to follow the shape of the upper end side of the inner spacer 154. Also, a stepped portion 128c notched in an annular shape is formed on the upper surface of the tapered portion 128b-1.

[0063] An annular groove portion 128d is provided at the outer peripheral end on the upper surface of the body portion 128b-2, and the cooling pipe 110 is disposed in this groove portion 128d. Also, an elongated mounting hole 128e is provided at one location along the axial direction on the lower surface of the body portion 128b-2. This mounting hole 128e is for inserting the temperature sensor 185. Note that reference numeral 116 is a cover for covering the cooling pipe 110.

[0064] Thus, the water-cooled spacer 128 formed in an annular shape as a whole has a configuration in which the body portion 128b-2 extends downward and radially outward from the support portion 128a via the tapered portion 128b-1. And, the thickness T2 of the overhanging portion 128b is larger than the thickness T1 of the support portion 128a (axial length). More specifically, the thickness T2 is about 2.5 times the thickness T1. Therefore, the water-cooled spacer 128 realizes high rigidity by the thick overhanging portion 128b. With this configuration, if the water-cooled spacer 128 is arranged at the position in FIG. 5, the tapered portion 128b-1 will cover the outside of the inner spacer 154.

[0065] Next, the effects of the present embodiment configured as described above will be described.

[0066] The turbo molecular pump 100 according to the present embodiment includes a water-cooled spacer 128. This water-cooled spacer 128 has a cooling pipe 110 and a temperature sensor 185. And, the temperature sensor 185 is provided in the vicinity of the cooling pipe 110.

[0067] The cooling water flowing through this cooling pipe 110 is controlled by turning on / off a valve (not shown) based on the temperature data from the temperature sensor 185. When the temperature inside the turbo molecular pump 100 rises, the valve of the cooling pipe 110 is turned on to control the temperature of the water-cooled spacer 128, particularly the temperature of the inner peripheral portion (the portion in contact with the gas flow path F1) of the water-cooled spacer 128.

[0068] In the temperature control system as described above, overshoot occurs with respect to the target temperature. However, since the temperature sensor 185 is in the vicinity of the cooling pipe 110 as described above, the temperature of the cooling pipe 110 can be detected with high precision. As a result, the control device 195 can control the temperature of the inner peripheral portion of the water-cooled spacer 128 in contact with the gas in the turbo molecular pump 100 with high precision based on the temperature data from the temperature sensor 185. Further, since the distance X1 is longer than the distance Y1, overshoot is less likely to occur in the temperature control of the inner peripheral portion of the water-cooled spacer 128 with respect to the temperature change of the cooling pipe 110. That is, the temperature change of the water-cooled spacer 128 with respect to the temperature change by the cooling pipe 110 is blunted, and it becomes easier to keep the temperature of the inner peripheral portion of the water-cooled spacer 128 at a constant temperature. Thus, according to the present embodiment, the temperature of the inner peripheral portion of the water-cooled spacer 128 in contact with the gas flow path F1 can be stably controlled without impairing the cooling effect of the cooling pipe 110. Further, since the temperature of the inner peripheral portion of the water-cooled spacer 128 is stabilized, the cooling state of the fixed blade 123 is also stabilized. As a result, the temperature of the rotating blade 102 is also stabilized.

[0069] Further, the water-cooled spacer 128 is made of a member having a higher conductivity than the outer cylinder 127 and the outer wall 126, specifically, an aluminum material. This is for the purpose of making it easier to change the temperature of the water-cooled spacer 128 with a small amount of cooling by using a member having a high thermal conductivity. By making the distance X1 longer than the distance X2, overshoot can be reduced and the target temperature can be reached earlier in the inner peripheral portion of the water-cooled spacer 128 in contact with the gas flow path F1.

[0070] That is, according to the present embodiment, by detecting the temperature change of the cooling pipe 110 with high precision by the temperature sensor 185 disposed in the vicinity of the cooling pipe 110, while controlling to suppress the temperature change of the cooling pipe 110, it becomes easier to control the temperature of the water-cooled spacer 128 at the target temperature. Further, by separating the cooling pipe 110 and the gas flow path F1 by a distance X1, even when a member with high thermal conductivity is used for the water-cooled spacer 128, it is possible to make it difficult for the rapid temperature change of the cooling pipe 110 to be transmitted to the inner peripheral surface of the water-cooled spacer 128 in contact with the gas flow path F1. Moreover, by making the water-cooled spacer 128 a member having a high thermal conductivity such as an aluminum material, even if the cooling pipe 110 is separated from the gas flow path F1, the temperature of the inner peripheral surface of the water-cooled spacer 128 in contact with the gas flow path F1 can be cooled to a desired temperature.

[0071] Also, since the temperature sensor 185 is provided radially inside the cooling pipe 110, there is an advantage that the temperature of the cooling pipe 110 can be detected with high precision without being affected by the temperature of the surrounding components of the water-cooled spacer 128.

[0072] Note that the temperature of the cooling water flowing through the cooling pipe 110 is arbitrary. As described above, since the water-cooled spacer 128 cools the fixed blade 123 and cools the rotating blade 102 by radiant heat, any temperature suitable for cooling the rotating blade 102 may be used. Therefore, depending on the temperature inside the turbo molecular pump 100, the temperature of the cooling water may be less than 100 degrees or may be 100 degrees or more.

[0073] Further, the water-cooled spacer 128 includes a support portion 128a and an overhanging portion 128b, and since the overhanging portion 128b has a thicker structure than the support portion 128a, deformation of the water-cooled spacer 128, particularly bending deformation in the axial direction, can be prevented. Also, since the overhanging portion 128b is configured to cover the outer peripheral side of the lower fixed wing spacer 125 so as to follow the shape (taper shape) of the upper portion of the inner spacer 154, the rigidity of the water-cooled spacer 128 can be increased without increasing the axial dimension by utilizing the dead space formed in the upper portion of the inner spacer 154. If the overhanging portion 128b extends upward from the support portion 128a in order to increase the rigidity of the water-cooled spacer 128, the axial dimension of the entire turbo molecular pump 100 becomes longer. However, with the shape of the present embodiment, the dimension does not need to be increased.

[0074] Also, since a heater 190 is provided on a heater spacer 153 which is a fixed component constituting a part of a screw groove pump section and is disposed on the downstream side of a plurality of rotating blades 102 and a plurality of fixed blades 123, the temperature of the gas to be exhausted can be controlled with higher precision.

[0075] (Second Embodiment) Next, a turbo molecular pump according to a second embodiment of the present invention will be described. FIG. 7 is a longitudinal sectional view of a turbo molecular pump 200 according to the second embodiment of the present invention, and FIG. 8 is an enlarged view of a main part showing an enlarged view of part B in FIG. 7. In the following, the same components as those in the first embodiment will be denoted by the same reference numerals and their description will be omitted.

[0076] As shown in these figures, in the second embodiment, the configuration of the water-cooled spacer is different from that in the first embodiment. Specifically, in the first embodiment, the water-cooled spacer 128 is disposed between the uppermost stage and the lowermost stage among the plurality of stages of fixed blades 123, but in the second embodiment, the water-cooled spacer 228 is disposed at the lowermost stage position among the plurality of stages of fixed blades 123. Therefore, the shape of the water-cooled spacer is different between the first embodiment and the second embodiment.

[0077] The water-cooled spacer 228 is made of an aluminum material as in the first embodiment and includes a cooling pipe 110 and a temperature sensor 185. The cooling pipe 110 is provided radially inward of the outer peripheral portion of the water-cooled spacer 228 as compared with the first embodiment. Specifically, the cooling pipe 110 is provided at a position separated by a distance X2 from the inner peripheral portion (the side closer to the gas flow path F2) of the water-cooled spacer 228. Further, the temperature sensor 185 is provided radially outside the cooling pipe 110 and in the vicinity of the cooling pipe 110. More specifically, the temperature sensor 185 is provided at a position radially outside by a distance Y2 from the cooling pipe 110. And the distance X2 is slightly longer than the distance Y2.

[0078] Note that the ratio of the distance X2 to the distance Y2 may be arbitrarily determined based on specifications such as the material of the water-cooled spacer 228, the flow rate and temperature of the cooling water flowing through the cooling pipe 110, and the flow rate and temperature of the gas flowing through the gas flow path F2. For example, it is preferably set within a range of about 1.5:1 to 3:1.

[0079] The water-cooled spacer 228 is disposed between the outer cylinder 127 and the base portion 129 and is fixed by bolts 115. Further, O-rings 192 are attached between the outer cylinder 127 and the water-cooled spacer 228 and between the base portion 129 and the water-cooled spacer 228 to maintain airtightness.

[0080] Next, the shape of the water-cooled spacer 228 will be described in detail. FIG. 9 is a longitudinal sectional view showing the details of the water-cooled spacer 228 shown in FIG. 8. As shown in FIG. 9, the water-cooled spacer 228 includes a support portion 228a and an overhanging portion 228b. The support portion 228a supports the adjacent fixed-wing spacers 125 in the axial direction and positions the adjacent fixed wings 123 in the axial direction (vertical direction). The overhanging portion 128b is provided to overhang radially outward from the support portion 128a. And the water-cooled spacer 228 has a substantially L-shaped cross section by the support portion 228a and the overhanging portion 228b.

[0081] The support portion 228a is provided with a stepped portion 228c for mounting the O-ring 192. Further, an annular groove portion 228d and a mounting hole 228e are provided on the lower surface of the protruding portion 228b. The cooling pipe 110 is attached to the groove portion 228d, and the temperature sensor 185 is attached to the mounting hole 228e.

[0082] According to this second embodiment, the same operational effects as those of the first embodiment are achieved. Further, in the second embodiment, since the water-cooled spacer 228 is arranged at the lowermost stage among the plurality of stages of the fixed wings 123, the water-cooled spacer 228 can be directly fixed to the base portion 129. Therefore, the outer wall 126 as in the first embodiment becomes unnecessary, and the structure can be simplified.

[0083] Note that the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention. All technical matters included in the technical idea described in the claims are the subject of the present invention. The above embodiments show preferred examples, but those skilled in the art can realize various alternative examples, modification examples, deformation examples, combination examples, or improvement examples from the content disclosed in this specification, and these are included in the technical scope described in the appended claims.

Explanation of Reference Numerals

[0084] 100, 200 Turbo molecular pump (vacuum pump) 102 (102a, 102b, 102c) Rotating blade 102d Cylindrical portion 103 Rotating body 113 Rotor shaft 116 Cover 122 Stator column 123 (123a, 123c, 123c) Fixed wing 125 (125a, 125b, 125c) Fixed wing spacer 126 Outer wall (casing) 127 Outer cylinder (casing) 128, 228 Water-cooled spacer (specific spacer) 128a, 228a Support portion 128b and 228b protrusion parts 128b-1 tapered part 128b-2 body part 128c and 228c step parts 128d and 228d annular grooves 128e and 228e mounting holes 129 base part 131 threaded spacer (threaded groove pump part) 133 exhaust port 153 heater spacer (fixed part) 154 inner spacer 155 heat insulation ring 185 temperature sensor 190 heater (heating means) 192 O-ring 195 control device

Claims

1. A casing, Inside the casing, a rotor shaft rotatably supported, A plurality of stages of rotating blades fixed to the rotor shaft and rotatable together with the rotor shaft, A plurality of stages of stationary blades fixed to the casing and arranged between the plurality of stages of rotating blades, A plurality of stages of stationary blade spacers for supporting the plurality of stages of stationary blades, a vacuum pump comprising: Temperature adjustment means provided in a specific spacer which is one stage of the plurality of stages of stationary blade spacers for adjusting the temperature of the specific spacer, A temperature sensor, comprising: The distance between the temperature sensor and the gas flow path of the turbo pump section composed of the plurality of stages of rotating blades and the plurality of stages of stationary blades is longer than the distance between the temperature sensor and the temperature adjustment means, The temperature adjustment means includes a cooling pipe through which a cooling medium flows, The supply and stop of the cooling medium are controlled by the temperature data from the temperature sensor, The specific spacer includes a support portion for supporting an adjacent stationary blade spacer in the axial direction, and an overhanging portion that projects radially outward from the support portion and covers the outer peripheral side of the stationary blade spacer, The thickness of the overhanging portion is greater than the thickness of the support portion, The temperature sensor and the cooling pipe are embedded in the overhanging portion, The temperature sensor is provided at a position between the gas flow path and the cooling pipe in the radial direction or outside the cooling pipe in the radial direction A vacuum pump characterized by that.

2. In the vacuum pump according to Claim 1, The casing includes an outer cylinder disposed on the outer peripheral side of the rotor shaft, and a base portion disposed below the outer cylinder, The specific spacer is made of a member having a higher thermal conductivity than the outer cylinder. A vacuum pump characterized by that.

3. In the vacuum pump according to Claim 2, The specific spacer is made of an aluminum material. A vacuum pump characterized by that.

4. In the vacuum pump according to Claim 1, The specific spacer is arranged between the uppermost stage and the lowermost stage of the plurality of stages of stationary blades. A vacuum pump characterized by that.

5. In the vacuum pump according to Claim 4, The specific spacer covers the outer peripheral side of the adjacent stationary blade spacer in the axial direction. A vacuum pump characterized by that.

6. In the vacuum pump according to any one of Claims 1 to 5, It is provided with a fixed component that constitutes a part of the screw groove pump section, arranged on the downstream side of the plurality of stages of rotating blades and the plurality of stages of stationary blades, The fixed component is a vacuum pump characterized by being heated by heating means.

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