JP2006077714A - Damper and vacuum pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a damper and a vacuum pump suitable for preventing transmission of vibration generated by the vacuum pump to a process chamber etc. <P>SOLUTION: This damper is provided with a first connecting part connected with the vacuum pump, a second connecting part connected with a device exhausted by the vacuum pump, bellows of which one end is fixed to the first connecting part and the other end is connected with the second connecting part, and a damping part inserted into a space between the first and second connecting parts. The damping part has a hollow part with which fluid is filled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a damper and a vacuum pump used in a vacuum pump, and more particularly to a damper and a vacuum pump that prevent propagation of vibration generated in the vacuum pump to a vacuum apparatus such as a process chamber or a measurement chamber using a fluid. .

  Conventionally, as a means for exhausting the gas in the process chamber to form a constant high vacuum degree in a process of performing processing in a high vacuum process chamber, such as a process such as dry etching or CVD in a semiconductor manufacturing process, Alternatively, for example, a vacuum pump such as a turbo molecular pump is used as means for exhausting the gas in the measurement chamber or the like attached to a lens barrel or a measurement chamber of an electron microscope.

  In this type of turbomolecular pump, a rotor that rotates at high speed is installed inside a cylindrical pump case, and a plurality of rotor blades that are cut and integrally formed are radially arranged in multiple stages. . Between each stage of the rotor blades, stator blades are alternately arranged in multiple stages inclined toward the inner side of the casing by a predetermined angle from a plane perpendicular to the axis of the rotor. When the rotor is driven and rotated by the motor unit, the rotor blades rotate with the rotor, and the gas in the process chamber is sucked from the intake port and exhausted from the exhaust port by the interaction between the rotor blades and the stator blades. It has become.

  In this turbo molecular pump, when the rotor rotates at a high speed, vibration due to cogging torque of the motor portion is generated, and vibration due to vibration is also generated because the rotor is not perfectly balanced. Therefore, for example, when this turbo molecular pump is directly connected without any intervention in the electron microscope barrel or measurement chamber, vibrations generated in such a turbo molecular pump are caused by this electron microscope or measurement chamber. It will be propagated to etc. In the electron microscope, the measurement chamber, or the process chamber that evacuates with this turbo molecular pump, precise work is performed. For example, a sample with a fine structure of about several mm can be obtained using an electron beam. In the case of observation, there are cases where a correct observation image cannot be obtained due to the influence of this vibration.

  Therefore, conventionally, in order to prevent the vibration generated in the turbo molecular pump from propagating to the process chamber or the like, the turbo molecular pump is connected to the process chamber or the like via a damper described in Patent Document 1. .

  As shown in FIG. 1 of Patent Document 1, this damper has a disk-shaped flange (reference numeral 24, reference numeral 25) with a hole for allowing gas to pass through in the center, and rubber (reference numerals 2, 3). ), A mass part (reference numeral 1) installed between the rubber (reference numerals 2, 3), and a bellows (reference numeral 4). The flange (reference numeral 25) is connected to the opening (reference numeral 7) of the vacuum apparatus (reference numeral 5) and the flange (reference numeral 25) is connected to the flange (reference numeral 26) of the turbo molecular pump (reference numeral 18) by bolts, clampers, etc. Has been. The bellows (reference numeral 4) is a thin tube having a smooth pleated chevron-shaped continuous cross section formed of stainless steel or the like, and exhibits elasticity by expanding and contracting the side surface formed in the chevron. The vibration generated by the turbo molecular pump (reference numeral 18) is absorbed and damped. The bellows (reference numeral 4) and the flange (reference numeral 25) and the bellows (reference numeral 4) and the flange (reference numeral 24) are brazed or welded, for example, and the bellows (reference numeral 4), the flange (reference numeral 25), and the bellows ( The outside air does not enter from the joint between the reference numeral 4) and the flange (reference numeral 24). Further, these joints are kept sufficiently strong against the vibration of the turbo molecular pump (reference numeral 18).

  The rubber (reference numeral 2, reference numeral 3) and the mass part (reference numeral 1) each have a cylindrical shape, and the inner diameter of the mass part (reference numeral 1) is larger than the outer diameter of the bellows (reference numeral 4). . The mass part (symbol 1) is made of a material having rigidity such as iron or stainless steel and having a density higher than that of rubber (symbols 2 and 3), and the mass of the mass part (symbol 1) is large. The vibration absorption capability of the damper portion (reference numeral 19) increases as the time increases. The rubber (reference numeral 2, reference numeral 3) is connected in series via a mass part (reference numeral 1) to constitute a vibration absorbing part (reference numeral 30).

  The vibration absorbing portion (reference numeral 30) is disposed concentrically outside the bellows (reference numeral 4), and both ends thereof are fixed or sandwiched between flanges (reference numerals 24 and 25), respectively, and rubber (reference numerals 2, 3). ), The mass part (reference numeral 1) and the flange (reference numeral 24, reference numeral 25) are joined to each other so as to have sufficient strength against vibration of the turbo molecular pump (reference numeral 18).

  The damper part (reference numeral 19) described in Patent Document 1 is configured as described above, and absorbs and attenuates vibration generated in the turbo molecular pump by the elastic force of rubber (reference numerals 2 and 3). This is to prevent the propagation of vibrations to vacuum devices such as chambers and measurement rooms.

  However, when the so-called evacuation is performed by sucking and exhausting the gas in the vacuum apparatus such as the chamber by the turbo molecular pump, the inside of the damper portion (reference numeral 19) is also in a high vacuum state. Since atmospheric pressure is acting outside the damper part (reference numeral 19), the damper part (reference numeral 19) is compressed and contracted by the pressure difference between the inside and outside of the damper part (reference numeral 19). Then, the rubber (reference numeral 2, reference numeral 3) constituting the damper portion (reference numeral 19) is also contracted, and the rubber (reference numerals 2, reference numeral 3) is solidified by this contraction. As a result, the rubber (reference numeral 2, reference numeral 3) is solidified. The elastic modulus of 3) is increased, and the vibration absorption capability is reduced. For this reason, there is a case where the vibration absorption and attenuation capability of the damper portion (reference numeral 19) cannot be fully exhibited.

JP 2002-295581 A

  The present invention has been made in view of such circumstances, and a problem to be solved is a damper and a vacuum pump suitable for preventing propagation of vibration generated by a vacuum pump to a process chamber, a measurement chamber, and the like. Is to provide.

  In order to achieve the above object, according to the present invention, a first connection part connected to a vacuum pump, a second connection part connected to a device evacuated by the vacuum pump, and one end of the first connection part are fixed. A damper having a bellows, the other end of which is fixed to the second connecting portion, and a vibration isolating portion inserted between the first connecting portion and the second connecting portion, wherein the vibration isolating portion is hollow. The hollow portion is filled with a fluid.

  The vibration isolator may be formed in an annular shape.

  In the present invention, the first connecting portion connected to the vacuum pump, the second connecting portion connected to the device evacuated by the vacuum pump, the first connecting portion and one end are fixed, and the other end is the first connecting portion. A damper having a bellows fixed to two connecting portions, and a vibration isolating portion inserted between the first connecting portion and the second connecting portion, wherein the vibration isolating portion includes a plurality of hollow portions. The hollow portion may be filled with a fluid.

  In addition, the fluid may be any one of air, compressed gas, and viscous material. This viscous material is formed from, for example, a silicon gel obtained by heat-curing a mixture of a reorganosiloxane, a curing agent, and a curing accelerator.

  In the present invention, a rotor shaft rotatably supported in a pump case having a gas intake port opened on the upper surface and a gas exhaust port opened on the lower side surface, and a drive motor for rotating the rotor shaft And a rotor composed of a multi-cylindrical body fixed to the rotor shaft and having a plurality of cylindrical portions having different diameters concentrically with respect to the rotor shaft center, a plurality of cylindrical portions of the rotor, and a space between the cylindrical portions. A screw composed of a multi-cylindrical stator having a plurality of cylindrical portions that are alternately positioned and fixed in the pump case, and a screw groove formed on a wall surface of the stator facing the cylindrical surface of the rotor. A vacuum pump comprising a groove pump mechanism, wherein the damper according to any one of claims 1 to 4 is connected to the gas intake port.

  As described above, the present invention employs a configuration in which the vibration isolating portion has a hollow portion and the hollow portion is filled with a fluid. For this reason, even when a compressive force is applied to the damper by evacuation, the fluid in the hollow portion does not solidify like the rubber used in the vibration absorbing portion of the conventional damper. Propagation of vibration to the process chamber or the like can be effectively prevented.

  Further, by changing the volume of the hollow part and the fluid in the hollow part, it is possible to vary the frequency of vibration that can be prevented.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a longitudinal sectional view showing a vacuum pump according to the present invention, but a damper is omitted, and a turbo molecular pump is described as one embodiment of the vacuum pump according to the present invention.

  The turbo molecular pump P is a composite type in which a turbo molecular pump mechanism Pt and a thread groove pump mechanism Ps are accommodated in a pump case 3 that is sealed by joining a base 2 to a hollow cylindrical casing 1. Vacuum pump.

  A gas intake port 4 is opened on the upper wall surface of the casing 1, and a gas exhaust port 5 is opened on the lower side wall surface of the base 2. A vacuum vessel such as a process chamber is screwed to the gas inlet 4 through a damper of the present invention, which will be described later, and an exhaust pipe 7 is attached to the gas outlet 5 to be connected to the auxiliary pump. Thus, the turbo molecular pump P is used as a means for exhausting the gas in the process chamber to form a constant high vacuum.

  A rotor shaft 10 that rotates at high speed by a drive motor 9 such as a high-frequency motor penetrates between upper and lower end surfaces of a stator column 8 that is erected inside the pump case 3, and the rotor shaft 10 includes a radial electromagnet 11-1. Are supported in the radial direction and the axial direction of the rotor shaft 10 by a magnetic bearing 11 including the axial electromagnet 11-2. Further, protective ball bearings 12 coated with a dry lubricant are provided at both ends of the rotor shaft 10 so that the rotor shaft 10 is not in contact with the rotor shaft 10 during normal operation, and only when the power supply of the magnetic bearing 11 is abnormal. It is adjusted so as to contact the rotor 10 and support the rotor shaft 10 and prevent the rotor shaft 10 and the magnetic bearing 11 from contacting each other.

  A hollow cylindrical rotor 13 disposed so as to surround the stator column 8 is screwed and fixed to the upper end portion of the rotor shaft 10 protruding from the stator column 8 in the axis L direction. Synchronizes with the rotor shaft 10 and rotates at high speed. The position of the rotor 13 integrated with the rotor shaft 10 is controlled by a position detection sensor 14 including a radial sensor 14-1 and an axial sensor 14-2.

  The upper half of the outer periphery of the rotor 13 functions as a turbo molecular pump mechanism Pt, and a plurality of blade-like rotor blades 15, 15,... Are integrally formed on the outer wall surface of the rotor 13 in the direction of the axis L of the rotor shaft 10. Yes. Further, a plurality of blade-shaped stator blades 16, 16,... Alternately positioned between the rotor blades 15, 15 are attached and fixed to the inner wall surface of the casing 1 by alternately stacking spacers 17, 17,. ing. On the other hand, the lower half of the outer periphery of the rotor 13 functions as a thread groove pump mechanism Ps, the outer wall surface of the rotor 13 is a flat cylindrical surface, and the inner wall surface of the casing 1 that opposes the outer wall surface of the rotor 13 at a narrow interval. A spiral thread groove 18 is engraved on the surface.

  The turbo molecular pump mechanism Pt and the thread groove pump mechanism Ps form a main flow path R for gas molecules flowing from the gas intake port 4 to the gas exhaust port 5. That is, in the turbo molecular pump mechanism Pt, when the rotor shaft 10 is rotationally driven by the drive motor 9, the rotor 13 and the rotor blade 15 rotate synchronously, and the rotor blade 15 rotating at high speed and the fixed stator blade 16 are rotated. Due to the interaction, gas molecules in a transitional flow are sent from the molecular flow sucked from the gas suction port 4 on the upper stage side to the screw groove pump mechanism Ps on the lower stage side. On the other hand, in the thread groove pump mechanism Ps, when the rotor shaft 10 is rotationally driven by the drive motor 9, the rotor 13 also rotates in synchronization with each other, and the cylindrical surface of the rotor 13 rotating at high speed and the fixed thread groove 18 are mutually connected. By the action, the gas molecules of the transition flow transferred from the upper turbo molecular pump mechanism Pt are compressed into a viscous flow, and the compressed gas molecules are exhausted to the lower gas exhaust port 5.

  As described above, when the turbo molecular pump P is operated to rotate the rotor 13 and the rotor blades 15 are rotated at a high speed, the vibration due to the cogging torque of the drive motor 9 is generated, and the rotor 13 is completely balanced. Since there is no removal, vibration due to vibration also occurs. Therefore, if the turbo molecular pump P is directly connected to the process chamber or the like without anything, the vibration of the turbo molecular pump P is propagated to the process chamber or the like, which hinders precision work in the process chamber or the like. Absent.

  Therefore, in order to prevent vibration generated in the turbo molecular pump P from propagating to the process chamber or the like, the turbo molecular pump P is connected to the process chamber or the like via the damper according to the present invention.

  Next, the damper of the present invention connected to the turbo molecular pump P and preventing the vibration generated in the turbo molecular pump P from propagating to the process chamber or the like will be described with reference to FIGS. .

<First embodiment>
FIG. 2A is a perspective view showing the overall configuration of the damper according to the present invention. The vibration isolator 104a, which is a characteristic part of the present invention, is a longitudinal sectional view. FIG. 2B is a longitudinal sectional view showing the overall configuration of the damper according to the present invention. A damper 100a shown in FIG. 5A includes a first connecting portion 101 connected to a process chamber (not shown), a second connecting portion 102 connected to the turbo molecular pump P, and the first connecting portion 101 and the second connecting portion. A bellows 103 fixed so as to be sandwiched between the first and second portions 102, and an annular vibration-proof portion 104 a inserted between the first connecting portion 101 and the second connecting portion 102 so as to surround the bellows 103. It consists of.

  The first connecting portion 101 includes an annular flange portion 101-1 and a circular center hole 101-2. A gas exhaust port such as a process chamber (not shown) and the center hole 101-2 are formed. Are fixed in such a manner as to hang from the process chamber or the like. As this fixing method, for example, several bolt holes may be provided in the flange portion 101-1, and fitting and fixing may be performed using bolts and nuts, or the flange portion 101-1 may be welded to a process chamber or the like. It may be fixed by doing.

  The 2nd connection part 102 is also the structure similar to this 1st connection part 101, and is comprised from the annular flange part 102-1 and the circular center hole 102-2. The second connecting portion 102 is fixed in such a manner that the turbo molecular pump P is suspended so that the gas inlet 4 of the turbo molecular pump P shown in FIG. Is done. As the fixing method, the same method as described above can be considered.

  The bellows 103 is a thin tube that is hollow and has a side surface formed in a bellows shape, and is formed of, for example, stainless steel. One end of the bellows 103 is fixed to the lower side of the flange portion 101-1 of the first connecting portion 101 so as to cover the central hole 101-2 of the first connecting portion 101, and the other end is connected to the second end. The second connecting portion 102 is fixed to the upper side of the flange portion 102-1 so as to cover the central hole 102-2 of the connecting portion 102. This fixing is performed by, for example, brazing or welding. Since the gas exhausted from the inside of the process chamber or the like passes through the bellows 103, the outside air does not enter from the fixed portion. In addition, the bellows 103 exhibits elasticity by expanding and contracting the bellows-like side surface, and absorbs and attenuates vibration generated by the turbo molecular pump P.

  The vibration isolator 104a is composed of a vibration absorbing portion 104a-1 having an annular shape surrounding the bellows 103, and an annular hollow portion 104a-2 formed inside the vibration absorbing portion 104a-1. Become.

  The vibration absorbing portion 104a-1 is made of, for example, a synthetic rubber such as natural rubber, chloropropylene rubber, nitrile rubber, or butyl rubber, and is appropriately selected from strength, heat resistance, oil resistance, durability, weather resistance, vibration damping properties, and the like. A suitable one may be selected. Further, as shown in FIG. 2B, the thickness of the vibration absorbing portion 104a-1 is smaller than the thickness in the length direction.

  Here, the hollow portion 104a-2 has an annular shape concentric with the annular vibration absorbing portion 104a-1.

  Further, the hollow portion 104a-2 is filled with a fluid, and the fluid is air, compressed gas, viscous material, or the like. This viscous material is formed from, for example, a viscous material such as silicon gel obtained by heating and curing a mixture of polyorganosiloxane, a curing agent, and a curing accelerator. Moreover, when filling this hollow part 104a-2 with compressed gas and a viscous body, in the vibration absorption part 104a-1 of the airtight structure which has the hollow part 104a-2 in the inside manufactured by the following manufacturing method, for example, The compressed gas and viscous material are sealed by providing a sealing port.

  As a method for filling the hollow portion 104a-2 with air, for example, when manufacturing the vibration isolator 104a having the annular hollow portion 104a-2 therein, the annular vibration absorbing portion 104a-1 is used. A horizontally-divided shape is manufactured by molding, and the two manufactured products are butted together so that an annular vibration absorbing portion 104a-1 is formed. It is formed by bonding with an adhesive or the like. The hollow portion 104a-2 is compressed in the direction sandwiched between the first connecting portion 101 and the second connecting portion 102 under the evacuation action of the turbo molecular pump P, and therefore can withstand this compressive force. As described above, the inside of the hollow portion 104a-2 needs to be pressurized, and has a sealed structure that does not release the applied pressure.

  Further, when the content of the fluid filled in the hollow portion 104a-2 is changed, the force for expanding the vibration absorbing portion 104a-1 from the inside of the hollow portion 104a-2 is changed, and as a result, formed from a synthetic rubber or the like. Further, the hardness of the vibration absorbing portion 104a-1 also changes, and the frequency of vibration that can be absorbed can also be changed.

  Next, the operation of the damper 100a configured as described above will be described.

  When the turbo molecular pump P is operated, the rotor blades rotate at a high speed as described above, and the gas in the process chamber or the like is supplied to the gas of the turbo molecular pump P by the interaction between the rotor blades and the stator blades arranged in multiple stages. It enters from the intake port and is discharged from the gas exhaust port. By repeating this series of operations, the process chamber is evacuated. In this vacuum state, the damper 100a according to the present invention connected between the turbo molecular pump P and the process chamber causes the bellows 103 to be pressed against the process chamber by the evacuation action as described above. Compressed in the direction.

  Then, the vibration isolator 104a is compressed in the direction sandwiched between the flange portions 101-1 and 102-1, and at the same time, the volume of the hollow portion 104a-2 inside the vibration absorbing portion 104a-1 contracts. Compressed. Furthermore, the air in the hollow portion 104a-2 is also compressed. When the air in the hollow portion 104a-2 is compressed, the air is gradually converted into a force for expanding the vibration absorbing portion 104a-1 from the inside. As the compression proceeds, the force for expanding gradually increases, and when the force for expanding the vibration absorbing portion 104a-1 from the inside and the compressive force due to the vacuuming balance are balanced, the contraction of the vibration isolating portion 104a stops. Stabilize.

  In this stable state, since the hardening in the vibration absorbing portion 104a-1 is suppressed, an elastic force can be exerted, and the turbo force is generated by this elastic force and the elastic force of the fluid in the hollow portion 104a-2. The vibration generated in the molecular pump P can be absorbed.

  By reducing the increase in the hardness of the vibration absorbing portion 104a-1, it is possible to suppress vibration at a lower frequency.

  In addition, in the damper 100a in the present embodiment, the entire damper 100a depends on how to select the material of the vibration absorbing portion 104a-1, the volume of the hollow portion 104a-2, and the type of fluid that fills the hollow portion 104a-2. Therefore, it is possible to absorb vibrations in a wide range of frequencies including low frequencies.

<Second embodiment>
Next, another embodiment of the damper according to the present invention will be described with reference to FIGS. FIG. 4A is a perspective view showing the entire damper according to the present invention, and the holding portion 106 that holds the vibration isolating portion 104b is omitted. Moreover, the figure (b) is a longitudinal cross-sectional view which shows the whole damper concerning this invention. Also in the damper 100b in this embodiment, the first connecting part 101 connected to the turbo molecular pump P, the second connecting part 102 connected to the chamber, and the first connecting part 101 and the second connecting part 102 are interposed. It is the same as that of the said 1st Example in the point comprised from the bellows 103 fixed so that it might be pinched | interposed. Further, the connecting method between the damper 100b and the chamber and the connecting method between the damper 100b and the turbo molecular pump P can be the same as the method according to the first embodiment.

  On the other hand, in the damper 100b in the present embodiment, as shown in FIG. 3A, the vibration isolator 104b has a plurality of spherically shaped vibration absorbers 104b-1 and the vibration absorbers 104b-1. The point formed by the formed hollow portion 104b-2 and the point that the vibration isolating portion 104b is held between the first connecting portion 101 and the second connecting portion 102 of the damper 100b by the holding portion 106 are as follows. This is a difference from the damper 100a in the first embodiment. These specific configurations will be described below with reference to FIG.

  As shown in FIG. 3B, the vibration isolator 104b is formed in a plurality of spherically shaped vibration absorbers 104b-1, 104b-1,... And in each of the vibration absorbers 104b-1. It is comprised from the hollow part 104b-2 made. The vibration isolator 104b is inserted and disposed between the first connecting part 101 and the second connecting part 102. As the arrangement method, for example, a method of individually disposing the bellows 103 in a radial manner with respect to the central axis of the bellows 103, or each vibration isolator 104b so as to surround the bellows 103 in an annular shape. There is a method of arranging a plurality of anti-vibration parts 104b in which the adjacent anti-vibration parts 104b are bonded with an adhesive or the like in an arranged state.

  In the latter case, before the bellows 103 is fixed to either the first connecting portion 101 or the second connecting portion 102, the center of the annular shape is formed from above the end of the bellows 103 that is not yet fixed. The bellows 103 is fitted and fixed so as to be covered by the holes of the bellows 103, and then fixed to either the non-fixed end of the bellows 103 and either the first connecting part 101 or the second connecting part 102. Thus, the vibration isolator 104b is disposed between the first connecting part 101 and the second connecting part 102.

  The vibration absorbing portion 104b-1 has a spherical shape, and is made of, for example, natural rubber, chloropropylene rubber, nitrile rubber, butyl rubber, or other synthetic rubber, and has strength, heat resistance, oil resistance, durability, and weather resistance. A suitable one may be selected from the viewpoint of the properties, vibration damping properties, and the like.

  The hollow portion 104b-2 has, for example, a spherical shape concentric with the vibration absorbing portion 104b-1. The hollow portion 104b-2 is formed by, for example, butting two rubber balls each having a hollow half formed into a hollow into a sphere, and bonding the butted portions with an adhesive or the like. It is formed by. In addition, since the vibration isolator 104b receives the evacuation action by the turbo-molecular pump P and is compressed particularly in the direction sandwiched between the first connecting part 101 and the second connecting part 102, it can withstand this compressive force. In addition, it is necessary to apply pressure to the inside of the hollow portion 104b-2, and the airtight structure is such that the pressure applied to the hollow portion 104b-2 is not released.

  In addition, the hollow portion 104b-2 is filled with a fluid, and the fluid is, for example, any one of air, compressed gas, and viscous material. This is the same as described in 1.

  The holding unit 106 is used to hold the vibration isolation units 104b, 104b,... Between the first connecting unit 101 and the second connecting unit 102. For example, natural rubber or chloropropylene rubber is used. It may be made of a synthetic rubber such as nitrile rubber or butyl rubber, and may be suitably selected from strength, heat resistance, oil resistance, durability, weather resistance, vibration damping properties, and the like. In addition, the holding unit 106 has a first holding unit 106-1 that contacts the lower surface of the flange portion of the first connecting unit 101 and a second holding unit that contacts the upper surface of the flange unit of the second connecting unit 102 when vacuuming. The anti-vibration parts 104b, 104b,... Are placed on the second holding part 106-2 and placed on the second holding part 106-2. In the state where the first holding unit 106-1 is arranged so as to cover each of the anti-vibration units 104b, 104b,... From above, both the holding units 106 are connected to the first connecting unit 101 and the second connecting unit. The anti-vibration part 104b is held between the two parts.

  The second holding unit 106-2 for placing the vibration isolator 104b on the upper surface has, for example, an annular shape surrounding the bellows 103, and the upper surface of each of the anti-vibration units 104b, 104b,. ..Even if the U-shaped groove is formed in an annular shape so that it can be easily placed, or each vibration isolator 104b, 104b,. In order to prevent the vibrating portions 104b, 104b,... From moving, the upper surface has a shape in which a plurality of hollow portions having a hemispherical shape are formed radially with respect to the axial direction of the bellows 103. Also good. Moreover, the 1st holding | maintenance part 106-1 is also comprised by the shape similar to this 2nd holding | maintenance part 106-2.

  Next, the operation of the damper 100b configured as described above will be described.

  Also in the damper 100b, the bellows 103 is compressed in a direction to be pressed against the process chamber by evacuation, and the vibration isolating portions 104b, 104b,... Are also sandwiched between the flange portions 101-1, 102-1. In the point that the hollow portion 104b-2 inside each vibration absorbing portion 104b-1 is also compressed in the direction in which the volume contracts, it is the same as described in the damper 100a. In addition, the holding portion 106 holding the vibration-proof portion 104b from above and below is also compressed in a direction so as to be sandwiched between both flange portions 101-1, 102-1. At this time, the air in the hollow portion 104b-2 is also compressed. When the air in the hollow portion 104b-2 is compressed, the air is gradually converted into a force for expanding the vibration absorbing portion 104b-1 from the inside. As the compression proceeds, the force for expanding gradually increases, and the resultant force of the force for expanding the vibration absorbing portion 104b-1 from the inside and the recovery force of the upper and lower holding portions 106, and the compressive force due to the evacuation action, Are balanced, the contraction of the vibration isolator 104b stops and stabilizes.

  In this stable state, since the hardening in the vibration absorbing portion 104b-1 is suppressed, an elastic force can be exerted, and the turbo force is generated by this elastic force and the elastic force of the fluid in the hollow portion 104b-2. The vibration generated in the molecular pump P can be absorbed.

  By reducing the increase in the hardness of the vibration absorbing portion 104b-1, it is possible to suppress vibrations at a lower frequency.

  Further, in the damper 100b according to the present embodiment, the material of the vibration absorbing portion 104b-1, the volume of the hollow portion 104b-2, the number of spherical vibration-proof portions 104b used, and the fluid filling the hollow portion 104b-2. Depending on how the type is selected, the elastic force of the entire damper 100a can be determined, so that vibrations of a wide range of frequencies including low frequencies can be absorbed.

Sectional drawing of a turbo-molecular pump. (A) The perspective view which shows the structure of the damper based on this invention. (B) The longitudinal cross-sectional view which shows the structure of the damper based on this invention. (A) The perspective view which shows the structure of the damper based on this invention. (B) The longitudinal cross-sectional view which shows the structure of the damper based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 2 Base 3 Pump case 4 Gas inlet 5 Gas outlet 6 Inlet flange 7 Exhaust pipe 8 Stator column 9 Drive motor 10 Rotor shaft 11 Magnetic bearing 11-1 Radial electromagnet 11-2 Axial electromagnet 12 Protective ball Bearing 13 Rotor 14 Position detection sensor 14-1 Radial direction sensor 14-2 Axial direction sensor 15 Rotor blade 16 Stator blade 17 Spacer 18 Thread groove 100a Damper 100b Damper 101 First connection portion 102 Second connection portion 103 Bellows 104 Vibration isolation portion 104a Anti-vibration part 104b Anti-vibration part 105 Hollow part 106 Holding part 106-1 First holding part 106-2 Second holding part P Turbo molecular pump Pt Turbo molecular pump mechanism part Ps Screw groove pump mechanism part R Main flow path of gas molecules

Claims (5)

A first connecting part connected to the vacuum pump, a second connecting part connected to the device evacuated by the vacuum pump, one end fixed to the first connecting part, and the other connected to the second connecting part. A damper having a bellows and a vibration isolating portion inserted between the first connecting portion and the second connecting portion,
The damper is characterized in that the vibration isolating portion has a hollow portion, and the hollow portion is filled with a fluid. The damper according to claim 1, wherein the vibration isolator is formed in an annular shape. A first connecting part connected to the vacuum pump, a second connecting part connected to the device evacuated by the vacuum pump, one end fixed to the first connecting part, and the other connected to the second connecting part. A damper having a bellows and a vibration isolating portion inserted between the first connecting portion and the second connecting portion,
The damper is characterized in that the vibration isolator is formed of a plurality of spherical bodies having a hollow portion, and the hollow portion is filled with a fluid. The damper according to any one of claims 1 to 3, wherein the fluid is any one of air, compressed gas, and viscous material. A rotor shaft rotatably supported in a pump case having a gas intake port on the upper surface and a gas exhaust port on the lower side surface;
A drive motor for rotating the rotor shaft;
A rotor composed of a multi-cylindrical body fixed to the rotor shaft and having a plurality of cylindrical portions having different diameters concentrically with respect to the rotor axis;
A stator comprising a plurality of cylindrical portions of the rotor, and a multi-cylindrical body having a plurality of cylindrical portions which are alternately positioned between the cylindrical portions and fixed in the pump case;
A vacuum pump comprising a thread groove pump mechanism composed of a thread groove engraved on the wall surface of the stator facing the cylindrical surface of the rotor,
The vacuum pump according to any one of claims 1 to 4, wherein the damper according to any one of claims 1 to 4 is connected to the gas inlet.

Images