US20030103847A1 - Vacuum pump - Google Patents
Vacuum pump Download PDFInfo
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- US20030103847A1 US20030103847A1 US10/308,819 US30881902A US2003103847A1 US 20030103847 A1 US20030103847 A1 US 20030103847A1 US 30881902 A US30881902 A US 30881902A US 2003103847 A1 US2003103847 A1 US 2003103847A1
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- cylinder
- rotor shaft
- mounting portion
- outer cylinder
- cylinders
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- 230000002093 peripheral effect Effects 0.000 claims description 20
- 238000005304 joining Methods 0.000 claims description 16
- 238000003780 insertion Methods 0.000 claims description 3
- 230000037431 insertion Effects 0.000 claims description 3
- 238000006073 displacement reaction Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 230000006835 compression Effects 0.000 description 4
- 238000007906 compression Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 230000003993 interaction Effects 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000004026 adhesive bonding Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 238000005211 surface analysis Methods 0.000 description 1
- 230000007306 turnover Effects 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D19/00—Axial-flow pumps
- F04D19/02—Multi-stage pumps
- F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D19/00—Axial-flow pumps
- F04D19/02—Multi-stage pumps
- F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
- F04D19/046—Combinations of two or more different types of pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D19/00—Axial-flow pumps
- F04D19/02—Multi-stage pumps
- F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
- F04D19/044—Holweck-type pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/26—Rotors specially for elastic fluids
- F04D29/266—Rotors specially for elastic fluids mounting compressor rotors on shafts
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Non-Positive Displacement Air Blowers (AREA)
- Applications Or Details Of Rotary Compressors (AREA)
Abstract
A multiple cylinder having a plurality of cylinders arranged concentrically and a rotor shaft rotatably disposed on the center axis of the multiple cylinder are provided in a pump casing. Each of the cylinders that constitute the multiple cylinder has a mounting portion, through which the cylinders are integrally fixed to the rotor shaft.
Description
- 1. Field of the Invention
- The present invention relates to a vacuum pump used for a semiconductor manufacturing apparatus, an electron microscope, a surface analysis apparatus, a mass spectrograph, a particle accelerator, an atomic fusion experimental apparatus and so on.
- 2. Description of the Related Art
- Pumps (hereinafter, referred to as compound-type vacuum pumps) that combine a turbo-molecular pump and a thread-groove pump are well known as this type of vacuum pump. Such compound-type vacuum pumps employ a structure in which a series of exhaust passages R1, R2, and R3 of the thread-groove pump are turned back in order to increase the pump compression ratio and miniaturize the whole pump, as shown in FIGS. 6 and 7.
- In order to obtain a turn-back structure of the exhaust passages R1, R2, and R3 of the thread-groove pump, the compound-type vacuum pumps shown in FIGS. 6 and 7 have a structure in which a substantially lower half of a rotor (rotation body) 70 which functions as a thread-groove pump has a
multiple cylinder 2 composed of twocylinders screw pump stators outer cylinder 4 and between the outer andinner cylinders rotor 70 works as a turbo-molecular pump, a plurality ofrotor blades 18 is integrally formed on the outer peripheral surface of the upper part of therotor 70. - Here, both the
rotors 70 of the compound-type vacuum pumps shown in FIGS. 6 and 7 have a structure of themultiple cylinder 2 and therotor blades 18. However, therotor 70 of the compound-type vacuum pump shown in FIG. 6 is formed such that themultiple cylinder 2 and therotor blades 18 are cut out from one rotor forming material. Therotor 70 of the compound-type vacuum pump shown in FIG. 7 is formed such that twocylinders lowermost rotor blade 18 by adhesive bonding or shrink fitting. - However, for manufacturing the
rotor 70 having the structure of themultiple cylinder 2 and therotor blades 18, by the method of cutting out themultiple cylinder 2 and therotor blades 18 from one rotor forming material as described above, the cutting shape is too difficult to form therotor 70 because of complication of its shape, thus causing an increase in the cost of the whole pump. - By the method of joining the two
cylinders lowermost rotor blade 18 later by adhesive bonding or shrink fitting, as described above, it is difficult to ensure the durability of the joint section, requiring high processing accuracy, thus leading to a higher cost of the whole pump. Also, the periphery of the joint sections of thecylinders lowermost rotor blade 18 has a large displacement especially by a centrifugal force during the operation of the pump; moreover, the vicinity of thelowermost rotor blade 18 has a displacement by thermal expansion due to the heat of compression that generates during the operation of the pump, so that the areas for mounting thecylinders cylinders cylinders rotor shaft 8 and therotor blades 18, in other words, off-core of therotor blades 18 is likely to occur. Such off-core of therotor blades 18 increases an imbalance of therotor 70 to cause vibration and a decrease in the life and damage to a shaft bearing for supporting therotor 70. - Particularly, when the
cylinders rotor blades 18 are made of different types of materials, the phase difference due to the difference in coefficient of thermal expansion, modulus of elasticity, and Poisson's ratio between the different types of materials causes a further unstable mounting state of thecylinders rotor 70. - The present invention has been made to solve the above problems and the object thereof is to prevent imbalance of a rotation body during the operation of the pump and to provide a highly-reliable low-cost vacuum pump capable of obtaining a stable operation for a long period of time.
- In order to achieve the above object, the present invention comprises: a multiple cylinder having a plurality of cylinders arranged concentrically; a rotor shaft rotatably disposed on the center axis of said multiple cylinder; and a screw pump stator having an exhaust passage of a thread-groove pump between it and each of said cylinders; wherein each of the cylinders constituting the multiple cylinder has a mounting portion, through which each cylinder is integrally mounted to the rotor shaft.
- In the present invention, preferably, the rotor shaft has a collar on the outer peripheral surface; each of the cylinders constituting the multiple cylinder has a mounting portion to the collar; and the mounting portions of the cylinders and the collar of the rotor shaft are integrally joined.
- In the above arrangement having the collar on the outer peripheral surface of the rotor shaft, preferably, the mounting portion of the outer cylinder is fixed to the surface of the collar and the mounting portion of the inner cylinder is fixed to the back of the collar.
- In the above arrangement having the collar on the outer peripheral surface of the rotor shaft, preferably, the mounting portion of the inner cylinder is disposed on the surface of the collar, on which the mounting portion of the outer cylinder is disposed; and both the mounting portions of the inner and outer cylinders are fastened to the collar with bolts passing therethrough.
- In the above arrangement having the collar on the outer peripheral surface of the rotor shaft, preferably, the collar has a shoulder; wherein the mounting portion of the outer cylinder is fastened to the upper step of the shoulder with bolts; and the mounting portion of the inner cylinder is fastened to the lower step of the shoulder with other bolts.
- In the present invention, preferably, the outer periphery of the end of the rotor shaft is tapered from the end face of the rotor shaft to a mounting position for the outer cylinder; and a tapered hole to be fitted to the tapered portion of the rotor shaft is opened in the mounting portion of the outer cylinder; wherein the rotor shaft and the outer cylinder are integrally joined by a counter joining structure in which the tapered hole and the tapered section are fitted to each other.
- In the above arrangement in which the outer cylinder is fixed to the rotor shaft, preferably, a push ring which is in contact with the periphery of the tapered hole of the mounting portion of the outer cylinder is disposed at the end face of the rotor shaft and wherein the outer cylinder is fastened to the rotor shaft with a bolt screwed into the end of the rotor shaft through a bolt insertion hole of the push ring.
- In the present invention, preferably, the outer periphery of the end of the rotor shaft is tapered from the end face of the rotor shaft to a mounting position for the inner cylinder through the mounting position for the outer cylinder; and a tapered hole to be fitted to the tapered portion of the rotor shaft is opened in each of the mounting portion of the outer cylinder and the mounting portion of the inner cylinder; wherein the rotor shaft, the outer cylinder, and the inner cylinder are integrally joined by a counter joining structure in which the tapered hole and the tapered section are fitted to each other.
- In the above arrangement in which the inner cylinder is fixed to the rotor shaft, preferably, a screw part is provided at the periphery of the end of the rotor shaft and at a position slightly higher than the mounting position for the inner cylinder; and the inner cylinder is fastened to the rotor shaft with a nut on the screw part tightened from above the mounting portion of the inner cylinder.
- In the present invention, preferably, a plurality of rotor blades and stator blades are alternately provided on the outer periphery of the outer cylinder of the cylinders; wherein the rotor blades are integrated with the outer peripheral surface of the outer cylinder; and the stator blades are fixed to the inner surface of a pump casing.
- In the present invention, preferably, the multiple cylinder includes a pair of inner and outer cylinders arranged concentrically; the screw pump stator includes a first screw-pump stator arranged at a position facing the outer peripheral surface of the outer cylinder and a second screw-pump stator arranged between the outer cylinder and the inner cylinder; the exhaust passage of the thread-groove pump includes a first gas-exhaust passage provided between the first screw-pump stator and the outer cylinder, a second gas-exhaust passage provided between the outer cylinder and the second screw-pump stator, and a third gas-exhaust passage provided between the second screw-pump stator and the inner cylinder; wherein the first gas-exhaust passage and the second gas-exhaust passage communicate under the outer cylinder; and the second gas exhaust passage and the third gas exhaust passage communicate above the second screw-pump stator.
- FIG. 1 is a sectional view of an embodiment of a vacuum pump according to the present invention;
- FIG. 2 is a sectional view of a second embodiment of a vacuum pump according to the present invention;
- FIG. 3 is a sectional view of a third embodiment of a vacuum pump according to the present invention;
- FIG. 4 is a sectional view of a forth embodiment of a vacuum pump according to the present invention;
- FIG. 5 is a sectional view of a fifth embodiment of a vacuum pump according to the present invention;
- FIG. 6 is a sectional view of a conventional vacuum pump; and
- FIG. 7 is a sectional view of another conventional vacuum pump.
- Referring to FIGS.1 to 5, embodiments of a compound-type vacuum pump incorporating a vacuum pump according to the present invention will be described hereinbelow.
- A compound-type vacuum pump shown in FIG. 1 includes a
multiple cylinder 2 as a rotation body in acylindrical pump casing 1. Themultiple cylinder 2 is arranged so that the upper end thereof faces agas suction port 3 at the upper part of thepump casing 1. - In this embodiment, the
multiple cylinder 2 has a double-cylindrical structure in which twocylinders rotor shaft 8 is provided so as to be rotatably erected on the center axis of themultiple cylinder 2 having the inner and outer pair ofcylinders - The
rotor shaft 8 has acollar 9 on the upper peripheral surface integrally. On the other hand, the twocylinders multiple cylinder 2 have mountingportions collar 9 at the respective upper parts thereof. By integrally joining therespective mounting portions cylinders collar 9 of therotor shaft 8, the twocylinders rotor shaft 8. - Several types of joining structures of the
cylinders rotor shaft 8 may be provided; however, this embodiment employs, as a joining structure, a structure in which mountingholes respective mounting portions outer cylinders respective mounting portions outer cylinders rotor shaft 8, and in which themounting portion 10 of theouter cylinder 4 is fastened to the surface of thecollar 9 withbolts 12, and themounting portion 11 of theinner cylinder 5 is fastened to the back of thecollar 9 with theother bolts 13. - In this embodiment, the radial bearing6 and the thrust bearing 7 that support the
rotor shaft 8 are magnetic bearings, with which therotor shaft 8 is supported in the radial direction and the thrust direction. - The
rotor shaft 8 is driven to rotate by a drive motor 14. The drive motor 14 of this embodiment has a structure in which amotor stator 16 is mounted to amotor stator column 15 provided inside themultiple cylinder 2 and amotor rotor 17 is mounted on the peripheral surface of therotor shaft 8 which faces themotor stator 16. - In the compound-type vacuum pump shown in FIG. 1, the substantially upper half of the
multiple cylinder 2 functions as a turbo-molecular pump and the substantially lower half of themultiple cylinder 2 functions as a thread-groove pump. - First, the structure of the substantially upper half of the
multiple cylinder 2 that functions as a turbo-molecular pump will be described. - A plurality of worked
rotor blades 18 andstator blades 19 are provided on the upper outer periphery of themultiple cylinder 2, that is, on the upper outer periphery of theouter cylinder 4 of the inner and outer pair ofcylinders rotor blades 18 and thestator blades 19 are alternately arranged along the center axis of rotation of themultiple cylinder 2. - More specifically, the
multiple cylinder 2 has, at the upper outer periphery, thestator blades 19 between the upper andlower rotor blades 18, or has therotor blades 18 between the upper andlower stator blades 19. - The
rotor blades 18 are integrated with the upper outer peripheral surface of theouter cylinder 4 by integral processing with theouter cylinder 4, and can be rotated integrally with the inner andouter cylinders stator blades 19 are fixed to the inner surface of thepump casing 1 throughspacers 20. - In the compound-type vacuum pump of this embodiment, when the
multiple cylinder 2 is rotated with therotor shaft 8, the gas molecules are exhausted from thegas suction port 3 at the upper part of thepump casing 1 toward thelowermost rotor blade 18 andstator blade 19 at the substantially upper half of themultiple cylinder 2 by the interaction of therotor blades 18 and thestator blades 19. The exhaust gas is sequentially fed to the next stage, that is, to the substantially lower half of themultiple cylinder 2 functioning as a thread-groove pump. - Next, in the multiple vacuum cylinder shown in FIG. 1, the structure of the substantially lower half of the
multiple cylinder 2 functioning as the thread-groove pump will be described. - While the
multiple cylinder 2 is constituted by a pair of inner andouter cylinders pump stator 21 is disposed at a position which faces the outer peripheral surface of theouter cylinder 4, and a second screw-pump stator 22 is disposed between theouter cylinder 4 and theinner cylinder 5. Both the first and second screw-pump stators cylinders multiple cylinder 2. - The first screw-
pump stator 21 has athread groove 23 at the inner surface, that is, a surface facing the outer peripheral surface of theouter cylinder 4. The second screw-pump stator 22 hasthread grooves 23 at the inner and outer surfaces, that is, a surface facing the inner peripheral surface of theouter cylinder 4 and a surface facing the outer peripheral surface of theinner cylinder 5. - A first gas-exhaust passage R1 is provided between the first screw-
pump stator 21 and theouter cylinder 4; a second gas-exhaust passage R2 is provided between theouter cylinder 4 and the second screw-pump stator 22; and a third gas-exhaust passage R3 is provided between the second screw-pump stator 22 and theinner cylinder 5. The first gas-exhaust passage R1 and the second gas-exhaust passage R2 communicate with each other at the lower end of theouter cylinder 4; and the second gas-exhaust passage R2 and the third gas-exhaust passage R3 are communicated with each other at the upper end of the second screw-pump stator 22. - In the compound-type vacuum pump of this embodiment, when the
multiple cylinder 2 is rotated with therotor shaft 8, the substantially lower half of themultiple cylinder 2 functions as a thread-groove pump. More specifically, a gas is exhausted by the relative motion between the twocylinders thread grooves 23 of thescrew pump stators - The exhaust gas first flows into the first gas-exhaust passage R1 from the
lowermost rotor blade 18 andstator blade 19 and flows therein downwardly in the drawing. The downward flowing gas is 180° reversed at the lower end of theouter cylinder 4, and then flows into the second gas-exhaust passage R2, and flows therein upwardly in the drawing. Subsequently, the upward flowing gas is 180° reversed at the upper end of the second screw-pump stator 22, then flows into the third gas-exhaust passage R3, and flows therein downwardly in the drawing, and finally flows from the lower end of theinner cylinder 5 to agas exhaust port 24 for discharge. - In the compound-type vacuum pump of this embodiment, while the substantially lower half of the
multiple cylinder 2 functions as a thread-groove pump, as described above, the series of gas exhaust passages (R1, R2, and R3) of this thread-groove pump turn over at the upper and lower points, that is, at the lower end of theouter cylinder 4 and the upper end of the second screw-pump stator 22. - The
gas suction port 3 at the upper part of thepump casing 1 connects to a high vacuum vessel including a process chamber of a semiconductor manufacturing apparatus, and thegas exhaust port 24 at the lower part of thepump casing 1 is set so as to communicate with an auxiliary pump (not shown). Therefore, the compound-type vacuum pump of this embodiment is constructed such that the turbo-molecular-pump functioning section that performs evacuation by the interaction between therotor blades 18 and thestator blades 19 is positioned on a high vacuum side, and the thread-groove-pump functioning section that performs evacuation by the interaction between the inner andouter cylinders thread grooves 23 is positioned on the auxiliary pump side (not shown). - Referring to FIG. 1, the use example and operation of the compound-type vacuum pump of this embodiment, constructed as described above, will be described. The arrows in the drawing indicate the flow direction of the exhaust gas in the pump.
- The compound-type vacuum pump in this drawing can be used, for example, as a means for evacuating the inside of a process chamber of the semiconductor manufacturing apparatus, in which the
gas suction port 3 of thepump casing 1 connects to the process chamber. - In the compound-type vacuum pump connected as described above, when the auxiliary pump (not shown) connected to the
gas exhaust port 24 is activated to evacuate the process chamber to a predetermined vacuum level and an operation start switch is then turned on, the drive motor 14 is activated to rotate themultiple cylinder 2 and therotor blades 18 integrally with therotor shaft 8. - In this case, in the evacuating operation for the gas molecules in the turbo-molecular-pump functioning section, the
uppermost rotor blade 18, which is rotating at a high speed, applies a momentum in the direction of thegas exhaust port 24 to gas molecules injected through thegas suction port 3, and the gas molecules having the downward momentum are carried to thestator blades 19 and are fed to the nextlower rotor blade 18. By repeating the application of momentum, the gas molecules are carried from thegas suction port 3 toward thelowermost stator blade 19 for discharge. - The gas molecules that have reached the
lowermost stator blade 19, as described above, are carried toward thegas discharge port 24 through the gas exhaust passages (R1, R2, and R3), where the gas molecules are compressed from a intermediate flow to a viscous flow by the relative movement between thecylinders thread grooves 23. The compressed gas is discharged from thegas exhaust port 24 to the exterior of the pump through the auxiliary pump (not shown). - The compound-type vacuum pump of this embodiment employs a structure in which the two
cylinders multiple cylinder 2 have the mountingportions cylinders rotor shaft 8. Therefore, when manufacturing the rotation body (rotor) of themultiple cylinder 2 constituted by theouter cylinder 4 with therotor blades 18 and theinner cylinder 5 without therotor blades 18, there is no need to cut out the multiple-cylindrical structure portion and therotor blades 18 from one rotor forming material, but after theouter cylinder 4 with therotor blades 18 and theinner cylinder 5 without therotor blades 18 have been formed, the outer andinner cylinders rotor shaft 8. Therefore, the processing is simplified as compared with the conventional art, thus reducing the cost of the whole pump. - During the operation of the pump, the displacement of the
rotor shaft 8 due to the heat of compression of the pump is smaller than that of therotor blades 18 and so on. Since this embodiment employs a structure in which thecylinders rotor shaft 8 having a small displacement, the load applied to the mounting portions of thecylinders cylinders rotor blades 18 integrated with theouter cylinder 4 from the geometrical central axes of therotor shaft 8 and therotor blades 18, so-called off-core of therotor blades 18, and resultant imbalance of themultiple cylinder 2, providing a high-reliable vacuum pump capable of obtaining a stable operation for a long period of time. - The joining structure of the
cylinders rotor shaft 8 may be other structures shown in FIGS. 2 to 5 in addition to that of the above-described embodiment shown in FIG. 1, which can also provide similar advantages. - In the joining structure of FIG. 2, the mounting
portion 11 of theinner cylinder 5 is arranged on the surface of thecollar 9, on which the mountingportion 10 of theouter cylinder 4 is arranged, and the mountingportions inner cylinders collar 9 of therotor shaft 8 withbolts 12 that pass through the mountingportions - In the joining structure of FIG. 3, the
collar 9 has ashoulder 25, to an upper step 25 a of which the mountingportion 10 of theouter cylinder 4 is fastened with thebolts 12, and to alower step 25 b of which the mountingportion 11 of theinner cylinder 5 is fastened with theother bolts 13. - The joining structure of FIG. 4 is a center lock structure in which the mounting
portion 10 of theouter cylinder 4 is fastened to the end center of therotor shaft 8 with thebolt 12. In the center lock structure, the outer periphery of the end of therotor shaft 8 is tapered from the end face to the position of mounting theouter cylinder 4; atapered hole 27 to be fitted on a taperedportion 26 of therotor shaft 8 is opened in the mountingportion 10 of theouter cylinder 4; and therotor shaft 8 and theouter cylinder 4 are joined in one by a counter lock structure in which the taperedhole 27 and the taperedportion 26 are fitted to each other. - In the joining structure of FIG. 4, for fixing the
outer cylinder 4 to therotor shaft 8, the mountingportion 10 of theouter cylinder 4 is mounted to the outer-cylinder-4 mounting position of therotor shaft 8 through the taperedhole 27 of the mountingportion 10 of theouter cylinder 4, then thepush ring 28 that is in contact with the periphery of the taperedhole 27 of the mountingportion 10 is arranged at the end face of therotor shaft 8, and thebolt 12 may be screwed into the end of therotor shaft 8 through a bolt insertion hole of thepush ring 28. Thus, the driving torque is applied to the mountingportion 10 of theouter cylinder 4 through thepush ring 28, and a wedge effect is produced between the taperedportion 26 and the taperedhole 27, thereby firmly fastening theouter cylinder 4 to therotor shaft 8. - In the joining structure of FIG. 4, the
inner cylinder 5 does not employ the center lock structure as in theouter cylinder 4, but adopts a structure in which the mountingportion 11 of thecylinder 5 is fastened to thecollar 9 on the peripheral surface of therotor shaft 8 with thebolts 13. - In the joining structure of FIG. 5, both the inner and outer cylinders employ the center lock structure. In this structure, the outer periphery of the end of the
rotor shaft 8 is tapered between the end face thereof to the mounting position for theinner cylinder 5 through the mounting position for theouter cylinder 4; the taperedhole 27 to be fitted on the taperedportion 26 of therotor shaft 8 is opened in the mountingportion 11 of theinner cylinder 5; and therotor shaft 8 and theinner cylinder 5 are joined in one by the counter lock structure in which the taperedhole 27 and the taperedportion 26 are fitted to each other. The outer periphery of the end of therotor shaft 8 has ascrew part 30 at a position slightly higher than the mounting position for theinner cylinder 5, onto which anut 31 is fitted. - In the joining structure of FIG. 5, for fixing the
inner cylinder 5 to therotor shaft 8, the mountingportion 11 of theinner cylinder 5 is mounted to the inner-cylinder-5 mounting position of therotor shaft 8 through the taperedhole 27 of the mountingportion 10 of theinner cylinder 5, then thenut 31 on thescrew part 30 may be fastened from above the mountingportion 11. Thus, the fastening force of thenut 31 causes a wedge effect between the taperedportion 26 and the taperedhole 27, thereby firmly fastening theinner cylinder 5 to therotor shaft 8. Since the center lock structure of theouter cylinder 4 is similar to that of the example shown in FIG. 4, a specific description thereof will be omitted. - In the above embodiments, while examples of forming the
thread grooves 23 in thescrew pump stators thread grooves 23 may be formed in thecylinders - In the above embodiments, while examples of employing the
multiple cylinder 2 composed of the twocylinders - In the above embodiments, examples of a so-called compound-type vacuum pump in which the upper half of the
multiple cylinder 2 functions as a turbo-molecular pump and the lower half functions as a thread-groove pump were described; however, the present invention can also be applied to a vacuum pump having a structure in which the wholemultiple cylinder 2 functions as a turbo-molecular pump, in other words, therotor blades 18 are provided over the whole peripheral surface of theouter cylinder 4, that is a so-called blade vacuum pump, and to a vacuum pump having only a function of a thread-groove pump without therotor blades 18 over the peripheral surface of theouter cylinder 4. - As described above, according to the present invention, each of a plurality of cylinders that constitute a multiple cylinder has a mounting portion, through which the cylinders are integrally fixed to a rotor shaft. Therefore, for example, when a rotation body (rotor) of a multiple cylinder constituted by an outer cylinder with rotor blades and an inner cylinder without the rotor blades is manufactured, there is no need to cut out the multiple-cylindrical structure portion and the rotor blades from one rotor forming material; but all that is needed is to form the outer cylinder with the rotor blades and the inner cylinder without the rotor blades separately, then combine the outer and inner cylinders concentrically, and fix it to the rotor shaft. Therefore, the processing is simplified as compared with the conventional art, thus reducing the cost of the whole pump.
- During the operation of the pump, the displacement of the rotor shaft due to the heat of compression of the pump is smaller than those of the rotor blades and so on. According to the present invention, since the cylinders are fixed to the rotor shaft having a small displacement, the load applied to the fixing sections of the cylinders is small, so that the cylinders can be maintained in stable positions for a long period of time, thus preventing problems due to an unstable mounting state, for example, the deviation of the center axes of rotation of the
rotor blades 18, which are provided at the outer cylinder constituting the multiple cylinder, from the geometrical central axes of the rotor shaft and the rotor blades, so-called off-core of the rotor blades, and resultant imbalance of the multiple cylinder, thus providing a high-reliable vacuum pump capable of obtaining a stable operation for a long period of time.
Claims (11)
1. A vacuum pump comprising:
a multiple cylinder having a plurality of cylinders arranged concentrically;
a rotor shaft rotatably disposed on the center axis of said multiple cylinder; and
a screw pump stator having an exhaust passage of a thread-groove pump between said screw pump stator and each of said cylinders;
wherein each of the cylinders constituting said multiple cylinder has a mounting portion, through which said each cylinder is integrally mounted to the rotor shaft.
2. A vacuum pump according to claim 1 , wherein said rotor shaft has a collar on the outer peripheral surface; each of the cylinders constituting said multiple cylinder has a mounting portion to said collar; and the mounting portion of said cylinder and the collar of said rotor shaft are integrally joined.
3. A vacuum pump according to claim 2 , wherein the mounting portion of said outer cylinder is fixed to the surface of said collar and the mounting portion of said inner cylinder is fixed to the back of said collar.
4. A vacuum pump according to claim 2 , wherein the mounting portion of said inner cylinder is disposed on the surface of said collar, on which the mounting portion of said outer cylinder is disposed and both the mounting portions of the inner and outer cylinders are fastened to said collar with bolts passing therethrough.
5. A vacuum pump according to claim 2 , wherein said collar has a shoulder; and wherein the mounting portion of the outer cylinder is fastened to the upper step of the shoulder with bolts and the mounting portion of the inner cylinder is fastened to the lower step of the shoulder with other bolts.
6. A vacuum pump according to claim 1 , wherein the outer periphery of the end of said rotor shaft is tapered from the end face of the rotor shaft to a mounting position for said outer cylinder and a tapered hole to be fitted to the tapered portion of the rotor shaft is opened in the mounting portion of said outer cylinder and wherein said rotor shaft and said outer cylinder are integrally joined by a counter joining structure in which said tapered hole and said tapered section are fitted to-each other.
7. A vacuum pump according to claim 6 , wherein a push ring which is in contact with the periphery of the tapered hole of the mounting portion of said outer cylinder is disposed at the end face of said rotor shaft, said outer cylinder being fastened to said rotor shaft with a bolt screwed into the end of the rotor shaft through a bolt insertion hole of the push ring.
8. A vacuum pump according to claim 1 , wherein the outer periphery of the end of said rotor shaft is tapered from the end face of the rotor shaft to a mounting position for said inner cylinder through the mounting position for said outer cylinder and a tapered hole to be fitted to the tapered portion of the rotor shaft is opened in each of the mounting portion of said outer cylinder and the mounting portion of said inner cylinder and wherein said rotor shaft, said outer cylinder, and said inner cylinder are integrally joined by a counter joining structure in which said tapered hole and said tapered section are fitted to each other.
9. A vacuum pump according to claim 8 , wherein a screw part is provided at the periphery of the end of said rotor shaft and at a position slightly higher than the mounting position for said inner cylinder and said inner cylinder is fastened to said rotor shaft with a nut on said screw part tightened from above the mounting portion of said inner cylinder.
10. A vacuum pump according to claim 1 , wherein a plurality of rotor blades and stator blades are alternately provided on the outer periphery of the outer cylinder of said cylinders, said rotor blades being integrated with the outer peripheral surface of the outer cylinder and said stator blades being fixed to the inner surface of a pump casing.
11. A vacuum pump according to claim 1 , wherein:
said multiple cylinder includes a pair of inner and outer cylinders arranged concentrically;
said screw pump stator includes a first screw-pump stator arranged at a position facing the outer peripheral surface of said outer cylinder and a second screw-pump stator arranged between said outer cylinder and said inner cylinder;
said exhaust passage of the thread-groove pump includes a first gas-exhaust passage provided between said first screw-pump stator and said outer cylinder, a second gas-exhaust passage provided between said outer cylinder and said second screw-pump stator, and a third gas-exhaust passage provided between said second screw-pump stator and said inner cylinder, said first gas-exhaust passage and said second gas-exhaust passage being communicated under said outer cylinder and said second gas exhaust passage and said third gas exhaust passage being communicated above said second screw-pump stator.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JPJP2001-370627 | 2001-12-04 | ||
JP2001370627A JP2003172291A (en) | 2001-12-04 | 2001-12-04 | Vacuum pump |
Publications (1)
Publication Number | Publication Date |
---|---|
US20030103847A1 true US20030103847A1 (en) | 2003-06-05 |
Family
ID=19179820
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/308,819 Abandoned US20030103847A1 (en) | 2001-12-04 | 2002-12-03 | Vacuum pump |
Country Status (6)
Country | Link |
---|---|
US (1) | US20030103847A1 (en) |
EP (1) | EP1318308A3 (en) |
JP (1) | JP2003172291A (en) |
KR (1) | KR20030045597A (en) |
CN (1) | CN1429994A (en) |
TW (1) | TW200300819A (en) |
Cited By (5)
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US20080286089A1 (en) * | 2007-05-15 | 2008-11-20 | Shimadzu Corporation | Turbo-molecular pump |
US20120257961A1 (en) * | 2009-12-24 | 2012-10-11 | Anest Iwata Corporation | Multistage vacuum pump |
US20180128280A1 (en) * | 2012-09-26 | 2018-05-10 | Edwards Japan Limited | Rotor and vacuum pump equipped with same |
US20220049705A1 (en) * | 2018-12-12 | 2022-02-17 | Edwards Limited | Multi-stage turbomolecular pump |
US11333154B2 (en) * | 2018-10-15 | 2022-05-17 | Shimadzu Corporation | Vacuum pump with a rotary body in a case with the rotary body having at least three balance correction portions accessible from an outside of the case for balance correction by an n-plane method |
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JP2006194083A (en) * | 2003-09-16 | 2006-07-27 | Boc Edwards Kk | Fixing structure of rotor shaft and rotor and turbo-molecular pump having the fixing structure |
JP2006077714A (en) * | 2004-09-10 | 2006-03-23 | Boc Edwards Kk | Damper and vacuum pump |
GB0618745D0 (en) * | 2006-09-22 | 2006-11-01 | Boc Group Plc | Molecular drag pumping mechanism |
CN102834620B (en) * | 2010-09-28 | 2016-03-02 | 埃地沃兹日本有限公司 | Exhaust pump |
TWI424121B (en) * | 2010-12-10 | 2014-01-21 | Prosol Corp | Turbo molecular pump with improved blade structures |
WO2012172990A1 (en) * | 2011-06-16 | 2012-12-20 | エドワーズ株式会社 | Rotor and vacuum pump |
JP6353195B2 (en) * | 2013-05-09 | 2018-07-04 | エドワーズ株式会社 | Fixed disk and vacuum pump |
US10253777B2 (en) * | 2013-09-30 | 2019-04-09 | Edwards Japan Limited | Thread groove pump mechanism, vacuum pump including thread groove pump mechanism, and rotor, outer circumference side stator, and inner circumference side stator used in thread groove pump mechanism |
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-
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- 2002-11-26 KR KR1020020073978A patent/KR20030045597A/en not_active Application Discontinuation
- 2002-11-27 EP EP02258145A patent/EP1318308A3/en not_active Withdrawn
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- 2002-12-04 CN CN02154776A patent/CN1429994A/en active Pending
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080286089A1 (en) * | 2007-05-15 | 2008-11-20 | Shimadzu Corporation | Turbo-molecular pump |
US8221052B2 (en) | 2007-05-15 | 2012-07-17 | Shimadzu Corporation | Turbo-molecular pump |
US20120257961A1 (en) * | 2009-12-24 | 2012-10-11 | Anest Iwata Corporation | Multistage vacuum pump |
US8517701B2 (en) * | 2009-12-24 | 2013-08-27 | Anest Iwata Corporation | Multistage vacuum pump |
US20180128280A1 (en) * | 2012-09-26 | 2018-05-10 | Edwards Japan Limited | Rotor and vacuum pump equipped with same |
US11333154B2 (en) * | 2018-10-15 | 2022-05-17 | Shimadzu Corporation | Vacuum pump with a rotary body in a case with the rotary body having at least three balance correction portions accessible from an outside of the case for balance correction by an n-plane method |
US20220049705A1 (en) * | 2018-12-12 | 2022-02-17 | Edwards Limited | Multi-stage turbomolecular pump |
Also Published As
Publication number | Publication date |
---|---|
EP1318308A2 (en) | 2003-06-11 |
KR20030045597A (en) | 2003-06-11 |
CN1429994A (en) | 2003-07-16 |
EP1318308A3 (en) | 2003-12-03 |
JP2003172291A (en) | 2003-06-20 |
TW200300819A (en) | 2003-06-16 |
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Legal Events
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AS | Assignment |
Owner name: BOC EDWARDS TECHNOLOGIES LIMITED, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NONAKA, MANABU;MIWATA, TOORU;KABASAWA, TAKASHI;REEL/FRAME:013548/0777;SIGNING DATES FROM 20021113 TO 20021121 |
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Owner name: BOC EDWARDS JAPAN LIMITED, JAPAN Free format text: MERGER;ASSIGNOR:BOC EDWARDS TECHNOLOGIES LIMITED;REEL/FRAME:015774/0864 Effective date: 20031201 |
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STCB | Information on status: application discontinuation |
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