Vacuum pump

Abstract

To provide a vacuum pump for suppressing influences on an external pipe due to the contact inconveniences of the rotor during the rotation of the rotor.SOLUTION: In the vacuum pump, a temperature rise ring 301 is provided. To the temperature rise ring 301, an exhaust port 133 is connected to which the external pipe is connected, and rotating force is directly or indirectly applied due to the contact inconveniences of the rotor during the rotation of the rotor. Separately from a connection portion between the temperature rise ring 301 and a casing (an outer cylinder 127a), rotation suppressing means (a hole 301a and a bolt 305) are provided for suppressing the rotation of the temperature rise ring 301 by the rotating force.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A vacuum pump such as a turbo molecular pump includes a rotor that rotates by a motor and a stator that is disposed around the rotor and forms a flow path together with the rotor, and collides gas molecules entering from an intake port with rotor blades of the rotor and stator blades of the stator and transfers them toward an exhaust port.

[0003] A certain vacuum pump further includes an annular member that heats the stator side in order to suppress adhesion, precipitation, and deposition of gaseous reaction raw materials, reaction products, etc. on the wall surface in the flow path, and an exhaust port is connected to the annular member (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the rotor rotates, if a problem occurs in which the rotor contacts a fixed member such as a stator due to the above-mentioned deposits, etc., a rotational force is applied to the fixed member itself and the above-mentioned annular member connected to the fixed member by the rotational force of the rotor, and a rotational force is also applied to the exhaust port connected to the annular member. Further, when the vacuum pump is in operation, an external pipe is connected to the exhaust port, and since the external pipe is fixed to an external structure, device, etc., a rotational force is also applied to the external pipe in such a problem, and there is a possibility that problems such as displacement, deformation, and detachment may occur in the external pipe.

[0006] Such problems may occur not only in the above-described exhaust port but also in other pipe connection parts connected to an annular member to which a rotational force is directly or indirectly applied when there is a contact failure of the rotor.

[0007] The present invention has been made in view of the above problems, and an object thereof is to obtain a vacuum pump that suppresses the influence on an external pipe caused by a contact failure of a rotor during rotation of the rotor.

Means for Solving the Problems

[0008] The vacuum pump according to the present invention includes a rotor, a stator, a casing that houses the rotor and the stator, an annular member to which a rotational force is directly or indirectly applied due to a contact failure of the rotor during rotation of the rotor, a pipe connection part that is connected to the annular member and to which an external pipe is connected, and rotation suppression means that suppresses rotation of the annular member due to the above-described rotational force, separately from a connection part between the annular member and the casing. Furthermore, it includes any one of the following configurations (A), (B), and (C). (A) The rotation suppression means includes a rotation restricting portion formed on the annular member and a rotation restricting member fixed to the casing and abutting against the rotation restricting portion by a rotational force. The annular member is a temperature-rising ring that raises the temperature of the gas flow path by the heat generation of the heater. The rotation restricting portion is a hole, and the rotation restricting member is a bolt or a pin disposed in the hole. When there is no contact defect, there is a gap between the hole and the bolt or the pin. (B) The annular member is a temperature-rising ring that raises the temperature of the gas flow path by the heat generation of the heater. The rotation suppression means includes a protrusion or a stepped portion formed on one of the temperature-rising ring and the casing and facing the other of the temperature-rising ring and the casing. When there is no contact defect, there is a gap between the protrusion or the stepped portion and the other of the temperature-rising ring and the casing. (C) It further includes a base portion that is the bottom of the casing. The rotation suppression means includes a rotation restricting portion formed on the annular member and a rotation restricting member protruding axially from the base portion and abutting against the rotation restricting portion by a rotational force. The annular member includes a flange and a hole or a notch formed in the flange. The rotation restricting portion is the hole or the notch, and the rotation restricting member is a bolt or a pin fixed to the base portion along the axial direction. When there is a contact defect, a part of the bolt or the pin protruding from the base portion abuts against the inner wall surface of the hole or the notch of the flange. When there is no contact defect, there is a gap between a part of the bolt or the pin protruding from the base portion and the inner wall surface of the hole or the notch of the flange.

Effects of the Invention

[0009] According to the present invention, a vacuum pump that suppresses the influence on an external pipe caused by a contact failure of a rotor during rotation of the rotor can be obtained.

[0010] The above or other objects, features, and advantages of the present invention will become more apparent from the following detailed description together with the accompanying drawings.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0013] Embodiment 1. A longitudinal sectional view of this turbo molecular pump 100 is shown in FIG. 1. In FIG. 1, in the turbo molecular pump 100, an intake port 101 is formed at the upper end of a cylindrical outer cylinder 127. And inside the outer cylinder 127, a rotating body 103 is provided in which a plurality of rotating blades 102 (102a, 102b, 102c ···), which are turbine blades for sucking and exhausting gas, are formed radially and in multiple stages on the circumference. A rotor shaft 113 is attached to the center of this rotating body 103, and this rotor shaft 113 is levitated and position-controlled in the air by, for example, a magnetic bearing with 5-axis control. The rotating body 103 is generally made of a metal such as aluminum or an aluminum alloy.

[0014] 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, etc., and detects the position of the rotor shaft 113 based on the change in the inductance of this conductive winding that changes according to the position of the rotor shaft 113. This upper radial sensor 107 is configured to detect the radial displacement of the rotor shaft 113, that is, the rotating body 103 fixed thereto, and send it to the control device 200.

[0015] In this control device 200, for example, a compensation circuit having a PID adjustment function generates an excitation control command signal for the upper radial electromagnet 104 based on the position signal detected by the upper radial sensor 107, and the amplifier circuit 150 (described later 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.

[0016] And this rotor shaft 113 is formed of a high magnetic permeability material (such as 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 respectively. Also, 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.

[0017] Furthermore, the axial electromagnets 106A, 106B are arranged sandwiching the 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 200.

[0018] Then, in the control device 200, 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.

[0019] In this way, the control device 200 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. The amplifier circuit 150 for performing excitation control on the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A and 106B will be described later.

[0020] 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 200 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.

[0021] 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 200, the detection signals of this phase sensor and the rotational speed sensor are used together to detect the position of the magnetic pole.

[0022] A plurality of fixed wings 123 (123a, 123b, 123c ···) are arranged with a slight gap from the rotary wings 102 (102a, 102b, 102c ···). 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.

[0023] 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. 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 ···).

[0024] 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. Outer cylinders 127, 127a are 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 127a. An exhaust port 133 is arranged above the base portion 129 and is communicated to the outside. The exhaust gas that has entered through the intake port 101 from the chamber (vacuum chamber) side and has been transferred is sent to the exhaust port 133.

[0025] Furthermore, depending on the application of the turbo molecular pump 100, a threaded spacer 131 is disposed between the lower part of the fixed wing 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 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, the 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 the threaded spacer 131 with a predetermined gap therebetween. The exhaust gas transferred to the screw groove 131a by the rotating blade 102 and the fixed blade 123 is sent to the base part 129 while being guided by the screw groove 131a.

[0026] The base part 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. Since the base part 129 physically holds the turbo molecular pump 100 and also serves as a heat conduction path, it is desirable to use a metal with high rigidity and high thermal conductivity such as iron, aluminum, or copper.

[0027] In such a configuration, when the rotary blade 102 is rotationally driven by the motor 121 together with the rotor shaft 113, exhaust gas is sucked from the chamber through the intake port 101 due to 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 frictional heat generated when the exhaust gas contacts the rotary blade 102 and conduction of heat generated by the motor 121. This heat is transferred to the fixed blade 123 side by radiation or conduction by gas molecules of the exhaust gas.

[0028] The fixed blade spacer 125 is joined to each other at the outer peripheral portion, and transfers heat received by the fixed blade 123 from the rotary blade 102, frictional heat generated when the exhaust gas contacts the fixed blade 123, etc. to the outside.

[0029] 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.

[0030] Also, depending on the use of the turbo molecular pump 100, in order to prevent the gas sucked from the intake port 101 from entering the electrical component portion 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 portion 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.

[0031] In this case, pipes (not shown) are arranged in the base portion 129, and purge gas is introduced through these pipes. 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 rotating blade 102.

[0032] 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 main body. The electronic circuit unit 141 is composed of electronic components such as a semiconductor memory like EEP-ROM and semiconductor elements for accessing it, 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 portion 129 that constitutes the lower part of the turbo molecular pump 100, and is closed by an airtight bottom cover 145.

[0033] 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 accumulates inside the turbo molecular pump 100.

[0034] For example, when SiCl4 is used as the process gas in an Al etching apparatus, in a low vacuum (760 [torr] to 10 -2When the pressure is low (e.g., [torr]) and the temperature is low (about 20 [°C]), it can be seen from the vapor pressure curve that solid products (e.g., AlCl3) precipitate and adhere and deposit inside the turbo molecular pump 100. As a result, when deposits of process gas accumulate inside the turbo molecular pump 100, these deposits narrow the pump flow path, causing a decrease in the performance of the turbo molecular pump 100. And the aforementioned products were in a situation where they were likely to solidify and adhere at high-pressure parts near the exhaust port 133 and near the threaded spacer 131.

[0035] 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 a temperature sensor (e.g., a thermistor) not shown is embedded in the base portion 129, for example. Based on the signal of this temperature sensor, the temperature of the base portion 129 is controlled to be kept at a certain high temperature (set temperature) by heating with the heater and cooling with the water-cooling pipe 149 (hereinafter referred to as TMS. TMS; Temperature Management System).

[0036] 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.

[0037] In FIG. 2, one end of the electromagnetic coil 151 constituting the upper radial electromagnet 104 etc. is connected to the positive electrode 171a of the power supply 171 via the transistor 161, and the other end is connected to the negative electrode 171b of the power supply 171 via the current detection circuit 181 and the transistor 162. And 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.

[0038] At this time, for 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. Also, for 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.

[0039] On the other hand, for the current regeneration diode 165, 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 current regeneration diode 166, 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.

[0040] The amplifier circuit 150 configured as described 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.

[0041] Furthermore, the amplifier control circuit 191 is composed of, for example, a digital signal processor unit (hereinafter referred to as the DSP unit) (not shown) of the control device 200, and this amplifier control circuit 191 is configured to switch the on / off of transistors 161 and 162.

[0042] The amplifier control circuit 191 is configured 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. Then, 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 period of PWM control. As a result, the gate drive signals 191a, 191b having these pulse widths are output from the amplifier control circuit 191 to the gate terminals of the transistors 161, 162.

[0043] Note that when passing through the resonance point during the acceleration operation of the rotational speed of the rotating body 103 or when a disturbance occurs during the constant speed operation, etc., it is necessary to control the position of the rotating body 103 with 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 occur. Also, 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).

[0044] In such a configuration, when both of the transistors 161, 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.

[0045] Also, when one of the transistors 161, 162 is turned on and the other is turned off, a so-called flywheel current is maintained. 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. Also, by controlling the transistors 161, 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.

[0046] 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 transistors 161 and 162 are turned on for a time corresponding to the pulse width time Tp1. Therefore, during this period, the electromagnetic current iL increases toward a current value iLmax (not shown) that can flow from the positive electrode 171a to the negative electrode 171b through the transistors 161 and 162.

[0047] On the other hand, when the detected current value is larger than the current command value, as shown in FIG. 4, only once during the control cycle Ts, both transistors 161 and 162 are turned off for a time corresponding to the pulse width time Tp2. Therefore, during this period, the electromagnetic current iL decreases toward a current value iLmin (not shown) that can be regenerated from the negative electrode 171b to the positive electrode 171a through the diodes 165 and 166.

[0048] 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, a flywheel current is held in the amplifier circuit 150.

[0049] The turbo molecular pump 100 is configured as described above. This turbo molecular pump 100 is an example of a vacuum pump. Further, in FIG. 1, the rotating blades 102 and the rotating body 103 are the rotors of the turbo molecular pump 100, the stationary blades 123 and the stationary blade spacer 125 are the stators of the turbo molecular pump portion, and the threaded spacer 131 is the stator of the threaded groove pump portion at the subsequent stage of the turbo molecular pump portion. Also, the outer cylinder 127 and the outer cylinder 127a are the casings of the turbo molecular pump 100 and house the above-described rotor and stator.

[0050] Furthermore, in FIG. 1, the temperature rising ring 301 is an annular member that raises the temperature of the gas flow path by the heat generation of the heater 302 and is made of the same material as the above-described stator. This temperature rising ring 301 and the heater 302 are also used in the above-described TMS.

[0051] This temperature-rising ring 301 is fixed to the above-described stator so as to be able to transfer heat to the stator, and is also fixed to the outer cylinder 127a with bolts or the like at its upper end. The temperature-rising ring 301 is separated from the base portion 129, and a gap 303 is formed between the two, and the two are thermally insulated by the gap 303. Further, a sealing 304 is provided in the gap 303. In this way, the temperature-rising ring 301 is not directly fixed to the base portion 129. Similarly, the threaded spacer 131 is not directly fixed to the base portion 129. Further, an exhaust port 133 is fixed to the temperature-rising ring 301, and an external pipe (not shown) is connected to the exhaust port 133. Then, gas is transferred to the exhaust port 133 through the gas flow path between the temperature-rising ring 301 and the threaded spacer 131, and is discharged to the external pipe through the exhaust port 133. Note that since the exhaust port 133 is a gas flow path and is similarly temperature-controlled, it is not directly fixed to the casing (outer cylinder 127a) and the base portion 129.

[0052] FIG. 5 is a side view showing a turbo molecular pump 100 as a vacuum pump according to Embodiment 1 of the present invention. As shown in FIG. 5, the exhaust port 133 is inserted and disposed in an insertion hole 127b formed in the outer cylinder 127a. The insertion hole 127b has a size larger than that of the exhaust port 133 so that the exhaust port 133 does not contact the outer cylinder 127a in consideration of heat insulation properties with respect to the casing and workability during assembly of the pump 100.

[0053] As described above, although the generation of deposits in the gas flow path is suppressed by the TMS, if a problem occurs in which the above-described rotor contacts the above-described stator due to deposits or the like in the gas flow path, the rotational force due to the rotation of the rotor is applied to the stator. At this time, the rotational force is also applied to the temperature-rising ring 301 fixed to the stator. Although the temperature-rising ring 301 is indirectly fixed to the base portion 129 via the outer cylinder 127a, the connection between the outer cylinder 127a and the temperature-rising ring 301 is made by bolts or the like arranged parallel to the axial direction of the pump 100. From the viewpoint of the arrangement space, it is difficult to use relatively large bolts or the like with high strength. Therefore, there is a possibility that the strength is insufficient against the rotational force applied to the temperature-rising ring 301 in the above-described problem. If the strength of the connection portion is insufficient against the rotational force, the rotational force is also applied to the exhaust port 133 fixed to the temperature-rising ring 301, and the above-described problems may occur.

[0054] Therefore, in the pump 100, rotation suppression means for suppressing the rotation of the temperature-rising ring 301 due to the rotational force with respect to the casing is provided. In the present embodiment, the rotation suppression means includes a rotation restricting portion formed in the temperature-rising ring 301 and a rotation restricting member fixed to the casing and abutting against the rotation restricting portion by the rotational force.

[0055] FIG. 6 is a cross-sectional view of the turbo molecular pump shown in FIG. 1 (a view showing the A-A cross section in FIG. 1). In the present embodiment, the rotation restricting portion of the temperature-rising ring 301 is a hole 301a along the radial direction of the pump 100 as shown in FIGS. 1 and 6, and the rotation restricting member is a bolt 305 disposed in the hole 301a. Specifically, a hole corresponding to the hole 301a is formed in the outer cylinder 127a, and the bolt 305 is fixed to the hole of the outer cylinder 127a by screw connection, and the tip of the bolt 305 is disposed in the hole 301a. Note that a pin may be used instead of the bolt 305. Further, the hole 301a does not penetrate the temperature-rising ring 301. Here, although the hole 301a and the bolt 305 are provided along the radial direction, they do not have to be along the radial direction.

[0056] In this embodiment, bolts 305 and pins as rotation restricting members can be installed from the outside of the casing after the rotor and the stator are housed inside the casing (outer cylinder 127a).

[0057] And when there is no contact defect in the above-mentioned rotor, there is a gap between the hole 301a and the bolt 305. This gap ensures heat insulation between the temperature-rising ring 301 and the casing (outer cylinder 127a).

[0058] In this embodiment, for example, as shown in FIG. 6, a plurality of holes 301a and bolts 305 are provided at equal angular intervals. Note that the number of the holes 301a and the bolts 305, and the diameter and material of the bolt 305 are selected based on the strength required for the rotational force at the time of the above-mentioned contact defect. That is, considering the connection strength between the temperature-rising ring 301 and the outer cylinder 127a as described above, the number of the holes 301a and the bolts 305, and the diameter and material of the bolt 305 are selected so that the temperature-rising ring 301 hardly rotates beyond the rotation angle until the rotation restricting member abuts against the rotation restricting portion due to the rotational force.

[0059] Next, the operation of the vacuum pump according to Embodiment 1 will be described.

[0060] During normal operation, the motor 121 operates and the rotor rotates based on the control by the control device 200. Thereby, the gas flowing in through the intake port 101 is transferred along the gas flow path between the rotor and the stator, and is discharged from the exhaust port 133 to the external pipe.

[0061] When a defect occurs in which the rotating rotor contacts the stator, a rotational force is applied to the stator due to the contact of the rotor, and thus the rotational force is also applied to the temperature-rising ring 301. At this time, the rotation of the temperature-rising ring 301 is restricted by the abutment of the holes 301a and the bolts 305, and thus the rotation of the exhaust port 133 connected to the temperature-rising ring 301 is suppressed. Therefore, even when such a defect occurs, the mechanical load applied to the external pipe connected to the exhaust port 133 is suppressed.

[0062] As described above, according to the above embodiment, the exhaust port 133 to which the external pipe is connected is connected to the temperature-rising ring 301, and the rotational force is directly or indirectly applied due to the contact failure of the rotor during the rotation of the rotor. And, separately from the connection portion between the temperature-rising ring 301 and the casing (outer cylinder 127a) (direct or indirect via other members), there are provided rotation suppression means (such as the hole 301a and the bolt 305) for suppressing the rotation of the temperature-rising ring 301 due to the above-described rotational force.

[0063] Thereby, the influence on the external pipe caused by the contact of the rotor with the fixed member (such as the stator) during the rotation of the rotor is suppressed.

[0064] If the above-described rotation suppression means is not provided and the temperature-rising ring 301 and the exhaust port 133 rotate (in the circumferential direction of the pump 100) when the above-described failure occurs, the exhaust port 133 will rotate until it contacts the inner wall of the insertion hole 127b of the outer cylinder 127a, and there is a possibility that a large mechanical load will be applied to the external pipe. On the other hand, by suppressing the rotation of the temperature-rising ring 301 by the above-described rotation suppression means, the rotation of the exhaust port 133 is also suppressed, and the mechanical load applied to the external pipe connected to the exhaust port 133 is suppressed.

[0065] Embodiment 2. In the vacuum pump according to Embodiment 2 of the present invention, there are provided rotation suppression means for suppressing the rotation of the temperature-rising ring 301 due to the above-described rotational force with respect to the base portion 129 to which the casing (outer cylinder 127a) is fixed. In the second embodiment, the rotation suppression means includes a rotation restricting portion formed on the temperature-rising ring 301 and a rotation restricting member that projects axially from the base portion 129 and abuts against the rotation restricting portion by the rotational force.

[0066] FIG. 7 is a longitudinal sectional view showing a turbo molecular pump 100 as a vacuum pump according to Embodiment 2 of the present invention. FIG. 8 is a cross-sectional view of the turbo molecular pump shown in FIG. 7 (a view showing the A-A cross section in FIG. 7). FIG. 9 is a perspective view showing an example of the rotation suppressing means in Embodiment 2.

[0067] In the second embodiment, as shown in FIGS. 7, 8, and 9, the rotation restricting portion of the temperature rising ring 301 is a notch 401a formed in the flange 401 of the temperature rising ring 301, and the rotation restricting member is a bolt 402 fixed to the base portion 129 along the axial direction. The bolt 402 is screwed to a female screw formed in a hole of the base portion 129, and its head is disposed within the notch 401a. Note that a pin may be used instead of the bolt 402. Further, a hole may be provided instead of the notch 401a.

[0068] When there is no contact failure of the above-described rotor, there is a gap between the notch 401a (inner wall surface thereof) and the bolt 402. Also, there is a gap between the flange 401 and the base portion 129. By these gaps, heat insulation between the temperature rising ring 301 and the base portion 129 is ensured.

[0069] In this embodiment, as shown in FIGS. 8 and 9 for example, a plurality of notches 401a and bolts 402 are provided at equal angular intervals. Note that the number of the notches 401a and bolts 402, and the diameter and material of the bolt 402 are selected based on the strength required for the rotational force at the time of the above-described contact failure. That is, the number of the notches 401a and bolts 402, and the diameter and material of the bolt 402 are selected so as to obtain a strength such that rotation of the temperature rising ring 301 hardly occurs beyond the rotation angle until the rotation restricting member abuts against the rotation restricting portion by the rotational force.

[0070] Next, the operation of the vacuum pump according to Embodiment 2 will be described.

[0071] If a problem occurs where the rotating rotor contacts the stator, a rotational force is applied to the stator due to the contact of the rotor, and thus the rotational force is also applied to the temperature-rising ring 301. At this time, the rotation of the temperature-rising ring 301 is restricted by the notch 401a of the temperature-rising ring 301 and the contact of the bolt 402, and consequently, the rotation of the exhaust port 133 connected to the temperature-rising ring 301 is suppressed. Therefore, even if such a problem occurs, the mechanical load applied to the external piping connected to the exhaust port 133 is suppressed.

[0072] Note that since the other configurations and operations of the vacuum pump according to the second embodiment are the same as those of the first embodiment, the description thereof is omitted.

[0073] Note 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 the intended advantages. That is, it is intended that such changes and modifications be included within the scope of the claims.

[0074] For example, in the above-described embodiment, the rotation restricting portion of the temperature-rising ring 301 is the hole 301a, but it may also be a groove, notch, etc. facing the casing, and as another embodiment, it may also be a protrusion, stepped portion, etc. facing the casing.

[0075] Also, in the above-described embodiment, as an annular member to which a rotational force is directly or indirectly applied due to a contact problem of the rotor during rotation of the rotor, the temperature-rising ring 301 to which the rotational force is indirectly applied is provided, and the above-described rotation suppressing means is provided on the temperature-rising ring 301. Instead, the above-described rotation suppressing means may be provided on an annular member that does not require temperature management. Further, the above-described rotation suppressing means may be provided on an annular member connected to a piping connection portion for another external piping different from the exhaust port 133. Note that when the annular member is a member that does not require temperature management, the gap between the above-described rotation restricting portion and the rotation restricting member may not be particularly provided.

[0076] Furthermore, in the above-described embodiment, the annular member such as the temperature-rising ring 301 may be a single member or a member formed by connecting a plurality of members.

[0077] Furthermore, in the above-described embodiment, the bolts 105 or pins may be arranged along the circumferential direction as described above and may also be arranged in the axial direction.

[0078] Furthermore, in the above-described embodiment, instead of the bolt 305 as the rotation restricting member described above, in the casing, a protrusion, a stepped portion, etc. facing the temperature-rising ring 301 may be provided. When there is no such contact problem as described above, a gap may be provided between the protrusion, the stepped portion, etc. of the casing and the temperature-rising ring 301, and the rotation of the temperature-rising ring 301 due to the rotational force caused by the above-described contact problem may be suppressed. Also, when the above-described rotation restricting member such as the bolt 305 is not provided as a member separate from the casing and the casing is provided with the protrusion, the stepped portion, etc., a gap is provided between the rotation restricting portion of the temperature-rising ring 301 and the casing.

[0079] Furthermore, in the above-described embodiment, the temperature-rising ring 301 and the threaded spacer 131 may be a single member. That is, the threaded spacer 131 may have a shape including the temperature-rising ring 301 and may be the above-described annular member.

Industrial Applicability

[0080] The present invention is applicable to, for example, a vacuum pump such as a turbo molecular pump.

Explanation of Reference Numerals

[0081] 100 Turbo molecular pump (an example of a vacuum pump) 102 Rotating blade (a part of an example of a rotor) 103 Rotating body (a part of an example of a rotor) 127 Outer cylinder (a part of an example of a casing) 127a Outer cylinder (a part of an example of a casing) 131 Threaded spacer (an example of a stator) 133 Exhaust port (an example of a pipe connection part) 301 Heating ring (an example of an annular member) 301a Hole (an example of a rotation restricting part) 305 Bolt (an example of a rotation restricting member) 401a Notch (an example of a rotation restricting part) 402 Bolt (an example of a rotation restricting member)

Claims

1. A rotor, A stator, A casing that houses the rotor and the stator, An annular member to which a rotational force is directly or indirectly applied due to a contact defect of the rotor during rotation of the rotor, A pipe connection portion that is connected to the annular member and to which an external pipe is connected, Rotation suppression means for suppressing rotation of the annular member due to the rotational force, separate from a connection portion between the annular member and the casing, comprising The rotation suppression means includes a rotation restricting portion formed on the annular member and a rotation restricting member fixed to the casing and abutting against the rotation restricting portion by the rotational force. The annular member is a temperature-rising ring that raises the temperature of a gas flow path by heat generation of a heater, The rotation restricting portion is a hole, The rotation restricting member is a bolt or a pin disposed in the hole, When there is no contact defect, there is a gap between the hole and the bolt or the pin, A vacuum pump characterized by the above.

2. A rotor, A stator, A casing that houses the rotor and the stator, An annular member to which a rotational force is directly or indirectly applied due to a contact defect of the rotor during rotation of the rotor, A pipe connection portion that is connected to the annular member and to which an external pipe is connected, Rotation suppression means for suppressing rotation of the annular member due to the rotational force, separate from a connection portion between the annular member and the casing, comprising The annular member is a temperature-rising ring that raises the temperature of a gas flow path by heat generation of a heater, The rotation suppression means includes a protrusion or a stepped portion formed on one of the temperature-rising ring and the casing and facing the other of the temperature-rising ring and the casing. When there is no contact failure, there is a gap between the protrusion or the stepped portion and the other of the temperature-rising ring and the casing. A vacuum pump characterized by the above.

3. A rotor, A stator, A casing for housing the rotor and the stator, An annular member to which a rotational force is directly or indirectly applied due to a contact failure of the rotor during rotation of the rotor, A pipe connection portion connected to the annular member and to which an external pipe is connected, Separate from the connection portion between the annular member and the casing, a rotation suppression means for suppressing the rotation of the annular member due to the rotational force, And a base portion which is the bottom of the casing. The rotation suppression means includes a rotation restricting portion formed on the annular member and a rotation restricting member protruding axially from the base portion and abutting against the rotation restricting portion by the rotational force. The annular member includes a flange and a hole or notch formed in the flange. The rotation restricting portion is the hole or the notch. The rotation restricting member is a bolt or a pin fixed to the base portion along the axial direction. When there is a contact failure, a part of the bolt or the pin protruding from the base portion abuts against an inner wall surface of the hole or the notch of the flange. When there is no contact failure, there is a gap between a part of the bolt or the pin protruding from the base portion and an inner wall surface of the hole or the notch of the flange. A vacuum pump characterized by the above.

4. The vacuum pump according to claim 3, wherein the annular member is a heating ring that raises the temperature of the gas flow path by the heat generation of the heater.

5. The vacuum pump according to any one of claims 1 to 4, wherein the pipe connection portion is an exhaust port.

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