TW202407219A - Vacuum pump - Google Patents

Abstract

A vacuum pump is proposed, which can more reliably prevent occurrence of an exhaust gas leakage from a space between a partition wall and a portion on which it is mounted. A vacuum pump has a casing having an outlet port, a rotating shaft rotatably supported inside the casing and rotated by an electric component portion, a rotor disposed outside an accommodating portion and fixed to the rotating shaft, a stator disposed on an outer peripheral side of the rotor, a pump channel provided between an outer peripheral surface of the rotor and an inner peripheral surface of the stator and configured such that the gas flows therethrough, a partition wall mounted on the stator and defining a gas channel from an outlet of the pump channel to the outlet port, and a heating means for heating the stator and the partition wall, wherein a seal member which suppresses intrusion of the gas is provided on a mounting surface of the stator and of the partition wall.

Description

Vacuum pump

The present invention relates to a vacuum pump.

For exhaust processing in a vacuum chamber installed in a semiconductor manufacturing apparatus, a vacuum pump such as a turbomolecular pump is used. In the semiconductor manufacturing process, there is a step of causing various process gases to act on the semiconductor substrate. The vacuum pump is used not only to create a vacuum in the chamber of the semiconductor manufacturing device, but also to discharge the process gases from the chamber.

This kind of process gas solidifies in the position where the gas phase is transferred to the solid phase according to the relationship between pressure and temperature shown in the vapor pressure curve, and is precipitated as a by-product. If such by-products accumulate in the vacuum pump, the flow path of the discharged gas may be narrowed, and the compression performance and exhaust performance of the vacuum pump may be reduced. For example, since the temperature of the base of the armored body of the vacuum pump or the housing (stator column) housing the electrical components such as electromagnets and motors that drive the rotor is relatively low, when the exhaust gas comes into contact with them, By-product accumulation.

Regarding this problem, conventionally, exhaust gas is prevented from directly contacting the base portion and the like by covering at least a portion of the base portion and the like with a partition. For example, in Patent Document 1, a partition plate (in the case of Patent Document 1, an insulating plate) is provided on the downstream side of the threaded groove pump part of the vacuum pump, and the partition plate covers at least a part of the low-temperature part, that is, the stator column or the base part. Prevents by-products from accumulating at the base. [Prior technical literature] [Patent Document]

[Patent Document 1] International Publication No. 2021/090738

[Problem to be solved by the invention]

However, the separator in Patent Document 1 is fixed to the threaded groove stator by, for example, bolts, as shown in FIG. 4 of the document. At this time, the diaphragm is basically in close contact with the threaded groove stator by tightening the bolts. However, due to deviations during processing of parts and other reasons, there is a risk that the mounting surfaces of the two cannot fully contact each other. In this case, the exhaust gas leaks from between the partition plate and the mounting surface of the threaded groove stator, and as a result, there is a concern that by-products may accumulate on the base or the like.

In view of this point, an object of the present invention is to provide a vacuum pump that can more reliably prevent abnormal leakage of exhaust gas from between the partition plate and the portion where the partition plate is mounted. [Technical means to solve problems]

The vacuum pump of the present invention is characterized by having: an armored body having an exhaust port; a receiving portion that accommodates an electrical component and is disposed inside the armored body; and a rotating shaft that rotates inside the armored body. freely supported and rotated by the above-mentioned electrical part; a rotor arranged outside the above-mentioned accommodating part and fixed to the above-mentioned rotation shaft; a stator arranged outside the above-mentioned rotor; and a pump flow path provided on the above-mentioned rotor. Between the outer circumferential surface and the inner circumferential surface of the above-mentioned stator, gas flows therein; a partition installed on the above-mentioned stator to delineate the flow path of the above-mentioned gas from the outlet of the above-mentioned pump flow path to the above-mentioned exhaust port; and heating A mechanism that heats the stator and the separator; and provides a sealing member that suppresses the intrusion of the gas on the mounting surface of the stator and the separator.

This vacuum pump preferably has a metal contact surface where the stator and the partition plate are in contact with each other on the mounting surface and on the upstream side of the gas with respect to the sealing member.

Furthermore, preferably, the stator and the separator are made of different materials.

Furthermore, it is preferable that the partition plate is made of a material with a higher thermal conductivity than that of the stator.

Furthermore, preferably, a non-contact sealing structure that suppresses the inflow of the gas into the accommodating portion is provided on at least part of the opposing surface of the rotor and the partition plate.

Furthermore, preferably, the partition plate is fixed to the stator by bolts from the axial direction of the rotation shaft.

Furthermore, preferably, the stator has a through hole connected to the exhaust port, and the mounting surface is provided at a position offset from the through hole with respect to the axial direction of the rotation shaft. [Effects of the invention]

The vacuum pump of the present invention has a stator mounted on the outer circumferential side of the rotor with a partition plate, and a sealing member that suppresses gas intrusion is provided on the mounting surface between the stator and the partition plate. That is, for example, even if a gas leakage gap occurs when the stator or separator is installed due to deviations in machining of the stator or the separator, it is possible to more reliably prevent gas leakage from the sealing member.

Hereinafter, a turbomolecular pump, which is one embodiment of the vacuum pump of the present invention, will be described with reference to the drawings.

A longitudinal cross-sectional view of the turbomolecular pump 100 is shown in FIG. 1 . In FIG. 1 , the turbomolecular pump 100 is provided with a suction port 101 at the upper end of the cylindrical outer tube 127 (part of the armor body). Furthermore, a rotating body 103 (rotor) that rotates around the central axis CA is provided inside the outer cylinder 127 . The rotor 103 is provided with a plurality of rotor blades 102 (102a, 102b, 102c...) that are turbine blades for sucking exhaust gas in a radial and multi-layered manner around the circumference. A rotor shaft 113 (rotation shaft) is installed at the center of the rotating body 103. The rotor shaft 113 is suspended in the air and its position is controlled by, for example, a five-axis controlled magnetic bearing. The rotating body 103 is generally made of metal such as aluminum or aluminum alloy.

The upper radial electromagnet 104 is composed of four electromagnets arranged in pairs on the X-axis and the Y-axis. Four upper radial sensors 107 are provided close to the upper radial electromagnet 104 and corresponding to each of the upper radial electromagnet 104 . The upper radial sensor 107 uses, for example, an inductive sensor or an eddy current sensor having a conductive winding, and detects the position of the rotor shaft 113 based on the change in 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 transmit it to a control device (not shown).

In this control device, for example, a compensation circuit with a PID (Proportional Integral Derivative: Proportional Integral Derivative) adjustment function generates an excitation control command for the upper radial electromagnet 104 based on the position signal detected by the upper radial sensor 107 Based on the excitation control command signal, the amplifier circuit 150 shown in FIG. 2 (described later) excites and controls the upper radial electromagnet 104, thereby adjusting the radial position of the upper side of the rotor shaft 113.

Furthermore, the rotor shaft 113 is made of a high magnetic permeability material (iron, stainless steel, etc.), and is attracted by the magnetic force of the upper radial electromagnet 104 . The adjustment is performed independently in the X-axis direction and Y-axis direction. In addition, 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 are adjusted below the rotor shaft 113 in the same way as the upper radial position. The radial position of the side.

Furthermore, the axial electromagnets 106A and 106B are arranged so as to sandwich the disc-shaped metal disk 111 provided at the lower part of the rotor shaft 113 up and down. The metal disk 111 is made of a high magnetic permeability material such as iron. In order to detect the axial displacement of the rotor shaft 113, an axial sensor 109 is provided, and its axial position signal is transmitted to the above-mentioned control device.

Moreover, in the above control device, for example, a compensation circuit with a PID adjustment function generates excitation control instructions for each of the axial electromagnet 106A and the axial electromagnet 106B based on the axial position signal detected by the axial sensor 109 signal, the amplifying circuit 150 performs excitation control on the axial electromagnet 106A and the axial electromagnet 106B respectively based on these excitation control command signals, whereby the axial electromagnet 106A uses magnetic force to attract the metal disk 111 upward, and the axial electromagnet 106B attracts the metal disc 111 downward to adjust the axial position of the rotor shaft 113.

In this way, the above-mentioned control device appropriately adjusts the magnetic force of the axial electromagnets 106A and 106B to affect the metal disk 111, so that the rotor shaft 113 is magnetically suspended in the axial direction and maintained in space in a non-contact manner. In addition, the amplifier circuit 150 that controls the excitation of the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B will be described later.

On the other hand, the motor 121 includes a plurality of magnetic poles arranged in a circumferential shape to surround the rotor shaft 113 . Each magnetic pole is controlled by the above-mentioned control device to drive the rotor shaft 113 to rotate through the electromagnetic force acting between the magnetic pole and the rotor shaft 113 . Furthermore, a rotation speed sensor (not shown) such as a Hall element, a resolver, an encoder, etc. is incorporated into the motor 121, and the rotation speed of the rotor shaft 113 is detected from a detection signal of the rotation speed sensor.

Furthermore, for example, a phase sensor (not shown) is installed near the lower radial sensor 108 to detect the phase of rotation of the rotor shaft 113 . In the above control device, the detection signals of the phase sensor and the rotation speed sensor are jointly used to detect the position of the magnetic pole.

A plurality of fixed wings 123 (123a, 123b, 123c...) are provided on the inner circumferential side of the outer cylinder 127 and the outer circumferential side of the rotating body 103, separated from the rotating wings 102 (102a, 102b, 102c...) by a slight gap. . The rotary wings 102 (102a, 102b, 102c...) are formed by being inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 because the molecules of the exhaust gas are moved downward through collision. The fixed wings 123 (123a, 123b, 123c...) are made of metals such as aluminum, iron, stainless steel, copper, or alloys containing these metals as components.

In addition, the fixed wing 123 is also formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and is arranged in a different layer from the rotary wing 102 toward the inside of the outer tube 127. Furthermore, the outer peripheral end of the fixed wing 123 is supported in a state of being inserted between a plurality of stacked fixed wing spacers 125 (125a, 125b, 125c...).

The fixed wing spacer 125 is an annular member 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 with a small gap on the outer periphery of the fixed wing spacer 125 . A base portion 129 (part of the armor body) is provided at the bottom of the outer cylinder 127 . An exhaust port 133 is formed on the base portion 129 and is connected to the outside. The exhaust gas enters the suction port 101 from the chamber (vacuum chamber) side and is moved toward the inside of the turbomolecular pump 100, and is sent to the exhaust port 133 on the downstream side.

Between the lower part of the fixed wing spacer 125 and the base part 129, a threaded spacer 131, a heater spacer 134, a partition (insulation wall) 135, a sealing member 136, and an insulating spacer 137 are provided. The above-mentioned fixed wing 123, fixed wing spacer 125, threaded spacer 131 and heater spacer 134 are components that constitute a part of the stator. In addition, detailed description about the heater spacer 134, the partition plate 135, the sealing member 136, and the thermal insulation spacer 137 is mentioned later.

The threaded spacer 131 is a cylindrical member made of metal such as aluminum, copper, stainless steel, iron, or alloys composed of these metals, and has a plurality of spiral threads engraved on its inner circumferential surface. Groove 131a. The spiral direction of the thread groove 131a is the direction in which the molecules of the exhaust gas are moved toward the exhaust port 133 side when they move in the rotation direction of the rotating body 103. A cylindrical part 102d hangs down from the lowest part of the rotating body 103 following the rotating wings 102 (102a, 102b, 102c...). The outer circumferential surface of the cylindrical portion 102d is cylindrical, protrudes toward the inner circumferential surface of the threaded spacer 131, and is close to the inner circumferential surface of the threaded spacer 131 with a predetermined gap. The threaded spacer 131 or the cylindrical portion 102d functions as a threaded groove pump part. The exhaust gas transferred to the threaded groove 131a by the rotating wing 102 and the fixed wing 123 is guided in the threaded groove 131a toward the exhaust port 133. Teleport. In addition, the function of the thread groove pump part can be arbitrarily set according to the purpose of the turbomolecular pump 100 .

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

In this structure, when the rotor blade 102 and the rotor shaft 113 are driven and rotated by the motor 121, the exhaust gas is sucked in from the chamber through the air inlet 101 by the action of the rotor blade 102 and the fixed blade 123. The rotation speed of the rotary wing 102 is usually 20000 rpm ~ 90000 rpm, and the peripheral speed of the front end of the rotary wing 102 reaches 200 m/s ~ 400 m/s. The exhaust gas sucked in from the suction port 101 passes through the pump flow path between the rotating wing 102 and the fixed wing 123 and between the threaded spacer 131 and the cylindrical part 102d, and passes through the space between the threaded spacer 131 and the heater. The flow path defined by the object 134 and the partition 135 is transferred to the exhaust port 133. At this time, although the temperature of the rotor blade 102 rises due to frictional heat generated when the exhaust gas contacts the rotor blade 102 or conduction of heat generated by the motor 121, this heat is transmitted through radiation or gas molecules of the exhaust gas. The conduction is transmitted to the fixed wing 123 side.

The fixed blade spacers 125 are joined to each other at the outer periphery to transmit heat received by the fixed blade 123 from the rotating blade 102 or frictional heat generated when exhaust gas contacts the fixed blade 123 to the outer tube 127 .

In addition, in the above description, the threaded spacer 131 is arranged on the outer periphery of the cylindrical portion 102d of the rotating body 103, and the threaded groove 131a is engraved on the inner peripheral surface of the threaded spacer 131. However, contrary to this, there is also a case where a thread groove is carved on the outer peripheral surface of the cylindrical portion 102d, and a spacer having a cylindrical inner peripheral surface is arranged around it.

Furthermore, depending on the purpose of the turbomolecular pump 100, the upper radial electromagnet 104, the upper radial sensor 107, the motor 121, and the lower radial electromagnet 105 are configured to prevent the gas sucked from the suction port 101 from intruding. , the electrical component composed of the lower radial sensor 108, the axial electromagnets 106A, 106B, the axial sensor 109, etc., and the stator column 122 (accommodating part) covers the surrounding electrical component, and the stator column The specified pressure is maintained by cleaning gas within 122 seconds.

The base portion 129 of this embodiment is provided with a cleaning port 115, and the cleaning gas is introduced through the cleaning port 115. The introduced cleaning gas passes through the gap 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 rotor blade 102 , and is sent to the exhaust port 133 .

Here, the turbomolecular pump 100 requires specification of the model and control based on unique parameters (for example, various characteristics corresponding to the model) that are individually adjusted. In order to store the control parameters, the turbomolecular pump 100 is provided with an electronic circuit unit (not shown) in its body. The electronic circuit part consists of semiconductor memories such as EEP-ROM (Electrically Erasable Programmable-Read Only Memory) and electronic components such as semiconductor elements used for their access, etc. It is composed of base plate etc. for installation. The electronic circuit part is accommodated in the lower part of the base part 129 constituting the lower part of the turbomolecular pump 100 , such as the lower part of the rotation speed sensor (not shown) near the center, and is closed by an airtight bottom cover 145 .

However, in the manufacturing steps of semiconductors, the process gas introduced into the chamber has the property of becoming solid when its pressure is higher than a specified value or its temperature is lower than a specified value. Inside the turbomolecular pump 100, the pressure of the exhaust gas is the lowest at the suction port 101 and the highest at the exhaust port 133. When the process gas is transferred from the suction port 101 to the exhaust port 133 , when its pressure is higher than a specified value or its temperature is lower than a specified value, the process gas becomes solid and adheres to and accumulates inside the turbomolecular pump 100 .

For example, it can be seen from the vapor pressure curve that when the Al etching device uses SiCl ₄ as the process gas, in low vacuum (760 [torr] ~ 10-2 [torr]) and low temperature (about 20 [℃]), The solid product (for example, AlCl ₃ ) precipitates, adheres, and accumulates inside the turbomolecular pump 100 . Therefore, if the precipitates of the process gas are accumulated inside the turbomolecular pump 100 , the deposits may cause the pump flow path to become narrow and the performance of the turbomolecular pump 100 to decrease. Moreover, the above-mentioned product is in a state where it is easy to solidify and adhere to the high-pressure portion near the exhaust port 133 or the threaded spacer 131 .

Therefore, in order to solve this problem, a heater (not shown) or an annular water-cooling tube is wound around the outer periphery of the base portion 129 and the like, and a temperature sensor (not shown) (such as a thermal sensor) is embedded in the base portion 129 . resistance), based on the signal of the temperature sensor, the heating of the heater or the cooling of the water-cooling tube is controlled in a manner to maintain the temperature of the base portion 129 at a constant high temperature (set temperature) (hereinafter referred to as TMS). TMS; Temperature Management System: temperature management system). In the turbomolecular pump 100 of this embodiment, a heater 138 (heating mechanism) and a temperature sensor 139 for performing TMS are mounted on the heater spacer 134 .

Next, the amplification circuit 150 for controlling the excitation of the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B of the turbomolecular pump 100 configured as above will be described. The circuit diagram of the amplifier circuit 150 is shown in Figure 2 .

In FIG. 2 , one end of the electromagnet winding 151 constituting the upper radial electromagnet 104 is connected to the positive electrode 171 a of the power supply 171 via the transistor 161 , and the other end is connected to the power supply 171 via the current detection circuit 181 and the transistor 162 . The negative electrode 171b. Furthermore, the transistors 161 and 162 are so-called power MOSFETs (Metal Oxide Semiconductor Field Effect Transistor), and have a structure in which a diode is connected between the source and the drain.

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

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

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

Furthermore, the amplification control circuit 191 is composed of, for example, a digital, signal, and processing section (hereinafter referred to as a DSP section, Digital Signal Processing) (not shown) of the above-mentioned control device, and the amplification control circuit 191 switches between the transistors 161 and 162. On/off.

The amplification control circuit 191 compares the current value detected by the current detection circuit 181 (the signal reflecting the current value is referred to as the current detection signal 191c) with the designated current command value. And, based on the comparison result, it is determined by the size of the pulse width (pulse width time Tp1, Tp2) generated within one cycle of PWM (Pulse Width Modulation) control, that is, the control cycle Ts. As a result, the self-amplification control circuit 191 outputs the gate drive signals 191a and 191b having the pulse width to the gate terminals of the transistors 161 and 162.

In addition, when the rotational speed of the rotating body 103 passes through a resonance point during accelerating operation, or when external interference occurs during constant speed operation, the position of the rotating body 103 needs to be controlled at high speed and with great force. Therefore, in order to rapidly increase (or decrease) the current flowing to the electromagnet winding 151, a high voltage of about 50 V is used as the power supply 171, for example. In order to stabilize the power supply 171, a normal capacitor (not shown) is connected between the positive electrode 171a and the negative electrode 171b of the power supply 171.

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

Furthermore, when one of the transistors 161 and 162 is turned on and the other is turned off, a so-called flywheel current is maintained. Furthermore, 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 suppressed to a low level. In addition, by controlling the transistors 161 and 162 in this manner, high-frequency noise such as high harmonics generated by the turbomolecular pump 100 can be reduced. Furthermore, by measuring the flywheel current with the current detection circuit 181, the electromagnet current iL flowing in the electromagnet winding 151 can be detected.

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

On the other hand, when the detected current value is greater than the current command value, both transistors 161 and 162 are turned off once in the control period Ts as shown in FIG. 4, which is equivalent to the pulse width time Tp2. amount of time. Therefore, the electromagnet current iL during this period decreases from the negative pole 171b toward the positive pole 171a toward a current value iLmin (not shown) that can be regenerated through the diodes 165 and 166.

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

Next, the above-mentioned heater spacer 134, partition plate 135, sealing member 136, and thermal insulation spacer 137 will be described in detail.

The heater spacer 134 is an integral ring-shaped member as shown in FIGS. 1 , 5 , and 6 , and is made of metal such as aluminum, copper, stainless steel, iron, or alloys containing these metals. For example, the heater spacer 134 is preferably made of a material with high strength in order to ensure strength at high temperatures. In this embodiment, considering this point, the heater spacer 134 is made of stainless steel. As shown in the figure, a threaded spacer 131 is installed on the upper part of the heater spacer 134. In addition, mounting holes for installing the heater 138 and the temperature sensor 139 are provided on the side of the heater spacer 134 , and the heater 138 and the temperature sensor 139 are held on the heater spacer 134 .

In addition, as shown in FIG. 5 , the heater spacer 134 has a flat metal contact surface 134 a extending in the horizontal direction at the radially inner lower portion, and a radial direction extending downward in the vertical direction from the radially outer side of the metal contact surface 134 a. The positioning surface 134b and the escape surface 134c whose inner diameter is larger than the radial positioning surface 134b and located below the radial positioning surface 134b. Furthermore, an annular recess 134d to which the sealing member 136 is mounted is provided on the lower surface of the heater spacer 134. In addition, as shown in the figure, the partition plate 135 is installed on the metal contact surface 134a, the radial positioning surface 134b, the retreat surface 134c and the annular recess 134d of the heater spacer 134. In the following description, this The other parts are called the mounting surfaces of the heater spacer 134 . A plurality of internal thread portions 134e arranged at intervals in the circumferential direction are provided on the metal contact surface 134a.

Furthermore, as shown in FIGS. 6(a) and (b) , the heater spacer 134 is provided with a circular through hole 134f that penetrates the heater spacer 134 in the radial direction. The through hole 134f communicates with the exhaust port 133 when the turbomolecular pump 100 is assembled. In addition, the through hole 134f is provided at a position that overlaps with the metal contact surface 134a, the radial positioning surface 134b, and the retreat surface 134c with respect to the axial direction of the heater spacer 134 (direction along the central axis CA).

The partition 135 is an integral ring-shaped member as shown in FIGS. 1 , 5 , and 6 , and is made of metal such as aluminum, copper, stainless steel, iron, or alloys containing these metals. The partition 135 is preferably heated by heat from the heater 138 installed on the heater spacer 134 as will be described later. In this embodiment, considering this point, it is made of a material with a higher thermal conductivity than the heater spacer 134 (for example, Aluminum) forms the partition 135.

In addition, the partition plate 135 of this embodiment is provided with an annular wall portion 135a in the shape of an annular plate. A cylindrical inner peripheral wall portion 135b extending upward is provided at the inner edge of the annular wall portion 135a, and a folded portion 135c protruding toward the radially outer side is provided at the upper end of the inner peripheral wall portion 135b (omitted in FIG. 6 icon). Furthermore, the partition plate 135 has a cylindrical outer peripheral wall portion 135e extending upward from a portion located radially inward of the outer edge portion 135d of the partition plate 135 . The upper surface of the outer peripheral wall portion 135e is a flat surface extending in the horizontal direction. Hereinafter, the upper surface of the outer peripheral wall portion 135e will be referred to as the metal contact surface 135f. In addition, the partition 135 is installed at the outer edge portion 135d, the outer peripheral wall portion 135e, and the metal contact surface 135f of the heater partition 134 as shown in the figure. In the following description, the outer edge portion 135d, the outer peripheral wall The portion 135e and the metal contact surface 135f are called the mounting surface of the partition 135.

The outer peripheral wall portion 135e is provided with a plurality of bolt through holes 135g that are spaced apart in the circumferential direction and penetrate the outer peripheral wall portion 135e in the up and down direction. The bolt through hole 135g is provided at a position corresponding to the internal thread portion 134e. Furthermore, with the mounting surface of the heater spacer 134 facing the mounting surface of the partition plate 135, the bolt 140 is inserted into the bolt through hole 135g and screwed into the internal thread portion 134e, so that the partition plate can be removed. 135 is installed on the heater spacer 134.

Furthermore, as shown in FIG. 6(c) , the partition plate 135 is provided with a semicircular notch portion 135h that penetrates the outer peripheral wall portion 135e in the radial direction. As shown in FIG. 6( a ), the notch 135 h is combined with the through hole 134 f to form a single hole in a state where the partition plate 135 is attached to the heater spacer 134 .

The sealing member 136 is formed in an annular shape by an elastic material (nitrile rubber, fluorine rubber, silicone rubber, etc.) and has the function of suppressing the intrusion of gas from between the adhering member and the sealing member 136 when in close contact with the member. Function. The sealing member 136 of this embodiment is an O-ring.

The insulating spacer 137 is a ring-shaped member as a whole and is made of a material with low thermal conductivity (heat is not easily transferred). The thermal insulation spacer 137 is made of, for example, stainless steel. As shown, an insulating spacer 137 is interposed between the base portion 129 and the heater spacer 134 , and the base portion 129 is insulated from the heater spacer 134 .

In the turbomolecular pump 100 composed of such a member, when the partition plate 135 is installed on the heater spacer 134 with the bolts 140, the sealing member 136 is in close contact with the lower surface of the annular recessed portion 134d and the outer edge portion 135d. surface. Furthermore, when the partition plate 135 is installed on the heater spacer 134, the radial positioning surface 134b is in contact with the upper peripheral surface of the outer peripheral wall portion 135e, and the metal contact surface 134a is in contact with the metal contact surface 135f. Therefore, the partition plate 135 faces each other. The heater spacer 134 is positioned radially, and also positioned in the up-down direction. In addition, since the retreat surface 134c located below the radial positioning surface 134b has a larger diameter than the inner diameter of the radial positioning surface 134b, when the partition plate 135 is installed on the heater spacer 134, it basically does not contact the outer peripheral wall portion 135e. outer surface. That is, when forming the radial positioning surface 134b and the retreat surface 134c, only the radial positioning surface 134b requires processing accuracy, so the processing cost of the heater spacer 134 can be suppressed.

Furthermore, when the partition plate 135 is attached to the heater spacer 134, a demarcation line formed by the threaded spacer 131, the heater spacer 134 and the partition plate 135 is formed below the threaded spacer 131 and the cylindrical portion 102d. And it leads to the pump flow path between the threaded spacer 131 and the cylindrical part 102d, and is connected to the annular flow path of the through hole 134f. In addition, the folded portion 135c of the partition 135 is located directly below the cylindrical portion 102d, and a gap is provided between the upper surface of the folded portion 135c and the lower surface of the cylindrical portion 102d. The gap is narrowed to such an extent that the cylindrical portion 102d and the folded portion 135c do not contact each other when the rotating body 103 rotates, and the gas flowing in the annular flow path does not flow into the stator column 122 through the gap, thereby functioning as a non-contact sealing structure.

In addition, the partition plate 135 is mounted on the heater spacer 134 with bolts 140 and is thermally connected to the heater spacer 134 . Therefore, the heat from the heater 138 is sufficiently transferred from the heater spacer 134 to the partition plate 135, so that the partition plate 135 can be effectively heated. In addition, although the inner peripheral wall portion 135b is separated from the mounting surface of the partition plate 135, since the partition plate 135 is made of a material with high thermal conductivity, the inner peripheral wall portion 135b is also heated by the heat from the heater 138. In this way, since the heater spacer 134 and the partition plate 135 are fully heated throughout their entire areas, precipitation of by-products caused by the exhaust gas in the annular flow path can be suppressed. In addition, the outer peripheral wall portion 135e extends long upward as shown in the figure, and when the partition plate 135 is attached to the heater spacer 134, its upper end is located close to the heater 138. That is, when the partition plate 135 having such an outer peripheral wall portion 135e is used, it can be said that the partition plate 135 is easily heated by the heat from the heater 138.

In addition, since the annular flow path is formed by the heater spacer 134 and the partition plate 135, there is a concern that the exhaust gas flowing in the annular flow path may pass through due to the processing or installation conditions of the heater spacer 134 and the partition plate 135. Between the mounting surface of the heater spacer 134 and the mounting surface of the partition plate 135, leakage occurs toward the base portion 129 or the insulating spacer 137, causing by-products to accumulate on the base portion 129 and the like. However, in the turbomolecular pump 100 of this embodiment, when the partition plate 135 is installed on the heater spacer 134, the sealing member 136 is in close contact with the lower surface of the annular recessed portion 134d and the upper surface of the outer edge portion 135d, so that discharge can be prevented. Gas leakage.

Next, a turbomolecular pump 200 according to a second embodiment of the vacuum pump of the present invention will be described with reference to FIGS. 7 to 9 . In addition, the turbo molecular pump 200 basically includes a heater spacer 234 and a partition plate 235 in place of the heater spacer 134 and the partition plate 135 of the turbo molecular pump 100 described above. Therefore, in the following, the heater spacer 234 and the partition plate 235 will be described in detail, and the other parts will be assigned the same reference numerals in the drawings and detailed descriptions will be omitted.

The heater spacer 234 is an annular member as a whole as shown in FIGS. 7 to 9 , and is made of metal such as aluminum, copper, stainless steel, iron, or alloys containing these metals. For example, the heater spacer 234 is preferably made of a material with high strength in order to ensure strength at high temperatures. In this embodiment, considering this point, the heater spacer 234 is made of stainless steel. A threaded spacer 131 is installed on the upper part of the heater spacer 234 as shown in FIG. 7 . In addition, mounting holes for installing the heater 138 and the temperature sensor 139 are provided on the side of the heater spacer 234 , and the heater 138 and the temperature sensor 139 are held in the heater spacer 234 .

Furthermore, as shown in FIG. 8 , the heater spacer 234 has a flat metal contact surface 234a extending in the horizontal direction at its lower portion. In addition, the metal contact surface 234a avoids the internal thread portion 234e described later and exists in a surrounding manner. On the radial inner side of the metal contact surface 234a, a radial positioning surface 234b extending upward in the vertical direction is provided. Furthermore, an annular recessed portion 234d to which the sealing member 136 is attached is provided in the metal contact surface 234a. As shown in the figure, the partition plate 235 is installed at the metal contact surface 234a, the radial positioning surface 234b, and the annular recess 234d of the heater spacer 234. In the following description, these parts are called heating. The mounting surface of the device spacer 234. In addition, the metal contact surface 234a is provided with a plurality of internal thread portions 234e spaced apart in the circumferential direction.

Furthermore, as shown in FIG. 9 , the heater spacer 234 is provided with a circular through hole 234f that penetrates the heater spacer 234 in the radial direction. The through hole 234f communicates with the exhaust port 133 when the turbomolecular pump 200 is assembled. In addition, the through hole 234f is provided at a position offset from the metal contact surface 234a, the radial positioning surface 234b, and the annular recess 234d relative to the axial direction of the heater spacer 234 (in the direction along the central axis CA) (compared to the metal contact surface 234a and the annular recessed portion 234d). Contact surface 234a and other upper positions).

The partition plate 235 is an integral ring-shaped member as shown in FIGS. 7 to 9 , and is made of metal such as aluminum, copper, stainless steel, iron, or alloys containing these metals. The partition 235 is preferably heated by heat from the heater 138 , similarly to the partition 135 described above. In this embodiment, considering this point, the partition 235 is made of a material (for example, aluminum) with a higher thermal conductivity than the heater partition 234 . 235.

Furthermore, the partition plate 235 is provided with an annular wall portion 235a in the shape of an annular plate. A cylindrical inner peripheral wall portion 235b extending upward is provided at the inner edge of the annular wall portion 235a, and a folded portion 235c protruding toward the radially outer side is provided at the upper end of the inner peripheral wall portion 235b. Furthermore, the partition plate 235 has an outer edge portion 235d located on the radially outer side of the annular wall portion 235a. The upper surface of the outer edge portion 235d is located lower than the upper surface of the annular wall portion 235a, and a step portion 235e extending in the vertical direction is provided between the outer edge portion 235d and the annular wall portion 235a. In addition, the upper surface of the outer edge portion 235d is a flat surface extending in the horizontal direction. Hereinafter, the upper surface of the outer edge portion 235d will be referred to as the metal contact surface 235f. In addition, the partition 235 is installed from the metal contact surface 235f of the heater spacer 234 to the step portion 235e as shown in the figure. In the following description, the space from the metal contact surface 235f to the step portion 235e will be The location is called the mounting surface of the partition 235. In addition, the metal contact surface 235f avoids the bolt through hole 235g described later and exists in a surrounding manner.

The outer edge portion 235d is provided with a plurality of bolt through holes 235g that are spaced apart in the circumferential direction and penetrate the outer edge portion 235d in the up and down direction. The bolt through hole 235g is provided at a position corresponding to the internal thread portion 234e. In addition, with the mounting surface of the heater spacer 234 facing the mounting surface of the partition plate 235, the bolt 140 is inserted into the bolt through hole 235g and screwed into the internal thread portion 234e, so that the partition can be connected. Plate 235 is mounted to heater spacer 234.

In the turbomolecular pump 200 constructed as above, when the partition plate 235 is mounted to the heater spacer 234 with the bolts 140, the sealing member 136 is in close contact with the lower surface of the annular recessed portion 234d and the outer edge portion 235d. upper surface. In addition, when the partition plate 235 is installed on the heater spacer 234, the radial positioning surface 234b is in contact with the side surface of the step portion 235e, and the metal contact surface 234a is in contact with the metal contact surface 235f. Therefore, the partition plate 235 is in contact with the heater. The spacers 234 are positioned radially and also in the up-and-down direction.

Furthermore, when the partition plate 235 is attached to the heater spacer 234, a demarcation line formed by the threaded spacer 131, the heater spacer 234 and the partition plate 235 is formed below the threaded spacer 131 and the cylindrical portion 102d. An annular flow path that leads to the pump flow path between the threaded spacer 131 and the cylindrical portion 102d and is connected to the through hole 234f. In addition, the folded portion 235c of the partition 235 is located directly below the cylindrical portion 102d, and a gap is provided between the upper surface of the folded portion 235c and the lower surface of the cylindrical portion 102d. In addition, this gap functions as a non-contact sealing structure similarly to the gap provided between the folded portion 135c and the cylindrical portion 102d shown in FIG. 5 .

The partition plate 235 is mounted on the heater spacer 234 with bolts 140 and is thermally connected to the heater spacer 234 . In addition, the partition 235 is made of a material with high thermal conductivity. Therefore, the inner peripheral wall portion 235b that is distanced from the mounting surface of the partition plate 235 is also heated by the heat from the heater 138 mounted on the heater spacer 234. In this way, since the heater spacer 234 and the partition plate 235 are fully heated throughout their entire ranges, precipitation of by-products from the exhaust gas can be suppressed in the annular flow path.

The above-mentioned annular flow path is formed by the heater spacer and the partition plate 235. Therefore, there is a concern that due to the processing or installation conditions of the heater spacer 234 and the partition plate 235, the exhaust gas flowing in the annular flow path passes between the mounting surface of the heater spacer 234 and the mounting surface of the partition plate 235, and is directed toward The base portion 129 or the thermal insulation spacer 137 leaks, causing by-products to accumulate on the base portion 129 and the like. However, in the turbomolecular pump 200 of this embodiment, when the partition plate 235 is installed on the heater spacer 234, the sealing member 136 is in close contact with the lower surface of the annular recessed portion 234d and the upper surface of the outer edge portion 235d, so that discharge can be prevented. Gas leakage. Furthermore, in this embodiment, the metal contact surface 234a and the metal contact surface 235f are in contact with each other on the upstream side of the sealing member 136, thereby suppressing the passage of exhaust gas. That is, since the amount of exposure of the exhaust gas to the sealing member 136 can be sufficiently suppressed by the metal contact surface 234a and the metal contact surface 235f, the sealing member 136 can be maintained even when the gas related to the deterioration of the sealing member 136 is discharged. performance. Especially in this embodiment, since the position where the heater spacer 234 and the partition plate 235 are fastened by the bolts 140 is the position where the metal contact surface 234a and the metal contact surface 235f are provided, the metal contact surface 234a and the metal contact surface 235f are Closer contact. In addition, since the metal contact surface 234a and the metal contact surface 235f exist to surround the internal thread portion 234e and the bolt through hole 235g, exhaust gas can also be prevented from leaking through the bolt through hole 235g. Therefore, deterioration of the sealing member 136 caused by the exhaust gas can be further suppressed.

However, in the above-mentioned turbo molecular pump 100, the through hole 134f connected to the exhaust port 133 is provided on the metal contact surface 134a, the radial positioning surface 134b and the retreat surface, as shown in FIGS. 6(a) and (b). The position where the parts of 134c overlap. That is, since the exhaust gas discharged from the exhaust port 133 through the through hole 134f flows near the mounting surface of the heater spacer 134 and the partition plate 135, there is a risk that the exhaust gas may intrude into the mounting surface. In contrast, as shown in FIGS. 9(a) and (b) , the through hole 234f of the turbomolecular pump 200 is provided at a position deviated from the metal contact surface 234a, the radial positioning surface 234b, and the annular recess 234d. That is, when the exhaust gas passes through the through hole 234f and is discharged from the exhaust port 133, it does not flow near the mounting surface of the heater spacer 234 and the partition plate 235, so the intrusion of the exhaust gas from the mounting surface can be suppressed.

Although one embodiment of the present invention has been described above, the present invention is not limited to the specified embodiment. As long as the above description is not particularly limited, it can be carried out within the scope of the gist of the present invention described in the patent claims. Various variations, alterations, combinations. In addition, the effects in the above-mentioned embodiments are only examples of the effects produced by the present invention, and it is not intended that the effects of the present invention are limited to the above-mentioned effects.

For example, in the stator of the above-mentioned embodiment, the threaded spacer 131 is a member different from the heater spacers 134 and 234. However, a member in which the threaded spacer and the heater spacer are integrated may also be used. In addition, the location where the bolt 140 is provided is not limited to the location where the metal contact surfaces 134a, 234a and the metal contact surfaces 135f, 235f are provided, but may also be located near the metal contact surfaces 134a, 234a and the metal contact surfaces 135f, 235f.

100,200: Turbomolecular pump (vacuum pump) 101: Suction port 102(102a,102b,102c): rotary wing 102d: Cylindrical part 103: Rotating body (rotor) 104: Upper radial electromagnet 105: Lower side radial electromagnet 106A, 106B: Axial electromagnet 107: Upper radial sensor 108: Lower radial sensor 109: Axial sensor 111:Metal disc 113:Rotor shaft (rotation axis) 115:Clean port 120: Protect bearings 121: Motor 122: Stator column (accommodation part) 123(123a,123b,123c): fixed wing 125(125a,125b,125c): fixed wing spacer 127:Outer cylinder 129:Basal part 131: With threaded spacer 131a: Thread groove 133:Exhaust port 134: Heater spacer 134a: Metal contact surface 134b: Positioning surface 134c: Retreat surface 134d: Annular recess 134e: Internal thread part 134f:Through hole 135:Partition 135a: Annular wall 135b: Inner peripheral wall part 135c: Turnback part 135d: outer edge part 135e: Outer peripheral wall part 135f: Metal contact surface 135g: bolt through hole 135h: Notch part 136:Sealing component 137:Thermal insulation spacer 138: Heater (heating mechanism) 139:Temperature sensor 140:Bolt 145: Bottom cover 150: Amplification circuit 151:Electromagnet winding 161:Transistor 161a: Cathode terminal 161b: Anode terminal 162:Transistor 162a: Cathode terminal 162b: Anode terminal 165: Diode 165a:Cathode terminal 165b: Anode terminal 166: Diode 166a: Cathode terminal 166b: Anode terminal 171:Power supply 171a: positive pole 171b: negative pole 181:Current detection circuit 191: Amplification control circuit 191a, 191b: Gate drive signal 191c: Current detection signal 234: Heater spacer 234a: Metal contact surface 234b: Radial positioning surface 234d: Annular recess 234e: Internal thread part 234f:Through hole 235g: bolt through hole 235:Partition 235a: Annular wall 235b: Inner peripheral wall part 235c: Turnback part 235d: outer edge part 235e: Step difference part 235f: Metal contact surface 235g: bolt through hole CA: central axis iL: electromagnet current Tp1, Tp2: pulse width time Ts: control cycle

FIG. 1 is a longitudinal sectional view schematically showing the first embodiment of the vacuum pump of the present invention. Figure 2 is a circuit diagram of the amplifier circuit of the vacuum pump shown in Figure 1. Figure 3 is a timing diagram showing the control when the current command value is greater than the detection value. Figure 4 is a timing diagram showing the control when the current command value is smaller than the detection value. Figure 5 is related to the vacuum pump shown in Figure 1. (a) is a partially enlarged view of part A, and (b) is a partially enlarged view of part B. Fig. 6 Regarding the heater spacer and the partition shown in Fig. 1, (a) is a perspective view showing the combined state of the heater spacer and the partition, (b) is a perspective view of the heater spacer, (c) is the partition Stereo view of the board. 7 is a longitudinal sectional view schematically showing a second embodiment of the vacuum pump of the present invention. Fig. 8 Regarding the vacuum pump shown in Fig. 7, (a) is a partial enlarged view of part C, and (b) is a partial enlarged view of part D. Fig. 9 Regarding the heater spacer and the partition shown in Fig. 7, (a) is a perspective view showing the combined state of the heater spacer and the partition, (b) is a perspective view of the heater spacer, (c) is the partition Stereo view of the board.

100: Turbomolecular pump (vacuum pump)

101: Suction port

102(102a,102b,102c): rotary wing

102d: Cylindrical part

103: Rotating body (rotor)

104: Upper radial electromagnet

105: Lower side radial electromagnet

106A, 106B: Axial electromagnet

107: Upper radial sensor

108: Lower radial sensor

109: Axial sensor

111:Metal disc

113:Rotor shaft (rotation axis)

115:Clean port

120: Protect bearings

121: Motor

122: Stator column (accommodation part)

123(123a,123b,123c): fixed wing

125(125a,125b,125c): fixed wing spacer

127:Outer cylinder

129:Basal part

131: With threaded spacer

131a: Thread groove

133:Exhaust port

134: Heater spacer

135:Partition

136:Sealing component

137:Thermal insulation spacer

138: Heater (heating mechanism)

139:Temperature sensor

145: Bottom cover

CA: central axis

Claims (7)

A vacuum pump is characterized by comprising: an armored body with an exhaust port; a receiving portion that receives the electrical component and is arranged inside the armored body; a rotating shaft, which is rotatably supported inside the armored body and is rotated by the electrical component; A rotor, which is arranged outside the above-mentioned receiving part and fixed to the above-mentioned rotating shaft; A stator, which is arranged on the outer peripheral side of the above-mentioned rotor; A pump flow path is provided between the outer peripheral surface of the rotor and the inner peripheral surface of the stator, and gas flows therein; A partition installed on the stator to delineate the flow path of the gas from the outlet of the flow path of the above pump to the exhaust port; and A heating mechanism that heats the above-mentioned stator and the above-mentioned separator; and A sealing member that suppresses the intrusion of the gas is provided on the mounting surface of the stator and the separator. The vacuum pump according to claim 1, wherein the mounting surface has a metal contact surface on the upstream side of the gas with respect to the sealing member, where the stator contacts the partition plate. The vacuum pump of claim 1, wherein the stator and the partition are made of different materials. The vacuum pump of claim 3, wherein the partition plate is made of a material with a higher thermal conductivity than the stator. The vacuum pump according to claim 1, wherein a non-contact sealing structure that suppresses the inflow of the gas into the accommodating portion is provided on at least a portion of the opposing surface of the rotor and the partition plate. The vacuum pump of claim 1, wherein the partition plate is fixed with bolts from the axial direction of the rotating shaft relative to the stator. The vacuum pump of claim 1, wherein the stator has a through hole connected to the exhaust port; and The mounting surface is provided at a position offset from the through hole with respect to the axial direction of the rotation shaft.