JPH076519B2 - Vacuum pump device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vacuum pump device, and more particularly to a vacuum pump suitable for obtaining a clean ultra-high vacuum for a semiconductor manufacturing device, a nuclear fusion device and the like.

[Conventional technology]

As shown in FIG. 8, the conventional vacuum pump device includes a turbo molecular pump 30 and a roughing pump 31 such as a rotary pump connected to the discharge side of the turbo molecular pump 30. The turbo molecular pump 30 is a casing having a suction port 22 connected to the ultra-high vacuum container on one side and a discharge port 23 on the other side.
21, a rotor 27 disposed in the casing 21, a rotor blade 28 provided on the outer periphery of the rotor 27, and the casing 21.
A rotor 29 provided on the inner surface and a drive motor 34 for rotating the rotor shaft 21A are provided, and the rotor 28 and the rotor blade 29 are arranged alternately to rotate the rotor 27 and the rotor blade 28. By carrying gas molecules from the suction port 22 to the discharge port 23 on the low vacuum side, an ultra-high vacuum can be obtained. Further, one end of the flexible tube 11 is connected to the discharge port 23 of the turbo molecular pump 30 via a quick coupling 10A, and the rough pump 31 is connected to the other end of the flexible tube 11 via a quick coupling 10B. It is connected. Further, in order to prevent the turbo molecular pump 30 or the ultra-high vacuum container from being contaminated by the reverse flow of oil from the roughing vacuum pump 31, the roughing vacuum pump 31 and the flexible tube 11 are used.
Trap 12 is interposed between and. As a device of that type, as described in JP-A-60-204997, a spiral groove pump and a centrifugal pump unit are formed, and the rotors of these pump units are mounted on a common rotary shaft. There is a composite vacuum pump that can exhaust from atmospheric pressure to ultra-high vacuum with one pump.

[Problems to be solved by the invention]

The above-mentioned conventional technique requires a roughing pump in addition to the turbo molecular pump, and thus requires a large installation space.
In addition, it is difficult to obtain a clean ultra-high vacuum because a roughing pump using oil is used. Further, a drive source for driving each of the turbo molecular pump and the roughing pump is required, and a power supply system is also required. Further, since a roughing pump such as a rotary pump generates vibration, it is necessary to prevent the vibration from being transmitted to the turbo molecular pump when the turbo molecular pump is used in a semiconductor manufacturing device or the like that is sensitive to vibration. When the turbo molecular pump unit and the roughing pump unit are integrated into a single shaft as described above, heat is generated in the rotor in the viscous flow region of the roughing pump unit and heat is generated in the rotor in the molecular flow region of the turbo molecular pump unit. Must be transmitted and cooled
The temperature is around 200 ° C, and there is no problem in strength and exhaust performance. Further, in the turbo molecular pump section, even if the casing is cooled, the heat is transferred by radiation, so that the cooling effect is small and the rotor becomes hot, resulting in poor performance.

An object of the present invention is to provide a vacuum pump device in which an installation space is reduced, a vibration region is achieved, and an ultrahigh vacuum can be obtained.

[Means for solving problems]

The above-mentioned object is a vacuum pump device provided with a first pump and a second pump in a casing having a suction port on one side and a discharge port on the other side, and the rotation shaft of the rotor of the first pump is This is achieved by connecting the rotating shaft of the rotor via a magnetic coupling.

[Action]

Since the first and second pumps are provided with pump elements for evacuating the molecular flow region, the intermediate flow region, and the viscous flow region in one casing, the installation space can be reduced. In addition, since the drive shafts of the two rotors are connected in a non-contact manner by magnetic bearings, vibration is reduced, and the heat generated by the second pump section with the drive motor is prevented from being transmitted to the first pump section. The reliability can be improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. First
The figure shows a sectional view of a vacuum pump device according to the present invention, a casing having a suction port 22 on one side and a discharge port 23 on the other side,
Inside this casing 21, an axial flow vane 24, a centrifugal vane 25, and a vortex flow vane 26 are provided. The axial flow blade 24 includes a plurality of moving blades 28 provided on the outer circumference of the rotor 27 and a plurality of moving blades 29 provided on the inner circumference of the casing 21.
The turbo molecular pump 30 is configured by alternately arranging and. In the turbo roughing pump 31, a centrifugal blade 25 and a vortex blade 26 are sequentially arranged on the discharge side of the turbo molecular pump 30 of the axial blade 24. These rotors 27 are supported by a radial magnetic bearing 32 and a thrust magnetic bearing 33 provided inside the casing 21. The turbo roughing pump 31 is provided with a drive motor 34 so that it can be rotated at high speed.
To connect the turbo molecular pump 30 and the turbo roughing pump 31,
Cylindrical magnetic couplings 35A and 35B of permanent magnets are provided at the ends of the rotors, and transmit the rotation of the turbo roughing pump 31 to the turbo molecular pump 30. Here, since the turbo roughing pump 31 is used in the viscous flow region, heat is generated, but the rotor is not heated to a high temperature by cooling the casing 21. However, the turbo molecular pump 30 is in the molecular flow region, and even if the casing is cooled, the cooling effect of the rotor is small due to heat transfer by radiation, and the rotor becomes high in temperature, causing a problem in strength. Therefore, it is necessary to block the heat conduction from the turbo roughing pump section, but by providing magnetic couplings of permanent magnets at the turbo molecular pump rotor shaft end and the turbo roughing pump rotor shaft end, each rotor is driven by one drive motor. Since it rotates, the heat generated by the turbo roughing pump 31 is not transmitted to the turbo molecular pump 30, so that the strength reliability can be improved.
In addition, the turbo roughing pump 31 requires a driving torque because it is about 10 ^-3 Torr from atmospheric pressure, and a motor of ³ to 5 kw is required, but the turbo molecular pump is a molecular flow region and requires about 30 to 50 W, so it is driven. At this time, the turbo molecular pump section is at atmospheric pressure and a driving torque is required. Even if the turbo roughing pump rotates, the turbo molecular pump section does not rotate, but the turbo roughing pump rotates and the degree of vacuum rises. The molecular pump also rotates to the same speed as the roughing pump. Thereby, an ultra-wide vacuum pump from atmospheric pressure to ultra-high vacuum can be obtained.

FIG. 2 shows an enlarged view of the magnetic coupling 35 portion. A plurality of permanent magnets 35B are arranged inside the drive side rotor shaft 27B, and a permanent magnet 35A is arranged outside the non-drive side rotor shaft 27A.
Are arranged and a cover ring 40 is provided on the outer circumference of the permanent magnet 35A so as not to scatter due to centrifugal force. By these, the rotation of the drive shaft is transmitted to the counter drive shaft. FIG. 3 shows a sectional view taken along the line YY of FIG. Further, a method of providing a cylindrical ring of a hysteresis material such as maraging steel instead of the permanent magnet 35A can be considered. Maraging steel has high strength and is also resistant to centrifugal force, enabling high-speed rotation.

FIG. 4 shows another embodiment of the present invention. 30 stages of turbo molecular pumps are arranged upstream of 31 stages of roughing pumps, and casing
A thirty-stage turbo molecular pump is supported by a radial bearing 32A and a thrust bearing 33A in an inner cylindrical casing 38 inside 21. Turbo roughing pump 31st upper part and turbo molecular pump
Even if multiple permanent magnets are radially arranged at the bottom of 30 steps
The same effect as the embodiment shown in the figure can be obtained. 5 and 6 show the magnetic coupling portion. Permanent magnets at the ends of the drive-side rotor shaft 27B and the non-drive-side rotor shaft 27A
The same effect can be obtained by arranging a plurality of 35A and 35B radially as shown in FIG.

FIG. 7 shows another embodiment of the present invention. In order to reduce the size and weight and to rotate at high speed, it is effective to shorten the length in the axial direction. By making the length short, the critical speed of the rotor shaft increases and high speed rotation becomes possible. As shown in FIG. 7, by providing a disk 39 of a high-strength hysteresis material such as maraging steel instead of the permanent magnet, the axial length and weight can be reduced. As a result, maraging steel is a high-strength material and can rotate at high speed.

〔The invention's effect〕

According to the present invention, it is possible to reduce the installation space because it is possible to exhaust from ultrahigh vacuum to atmospheric pressure by disposing a pump element for performing vacuum exhaust of the turbo molecular pump unit and the turbo roughing pump unit in one casing. It is possible to obtain a clean ultra-high vacuum. Further, by connecting the rotor drive shaft of each pump element with a magnetic coupling, there is an effect that one drive source is enough. Since each pump part is connected in a non-contact manner by magnetic coupling, there is no heat conduction and there is an effect that the reliability of strength can be improved by preventing the temperature of the turbo molecular pump part from rising. Furthermore, the drive motor of the turbo roughing pump is 3-5kw.
Compared with, a turbo molecular pump can be driven by 30 to 50 W, so that a low torque coupling such as a magnet coupling is required, so that magnetic coupling is convenient.

[Brief description of drawings]

FIG. 1 is a sectional view of a vacuum pump device showing an embodiment of the present invention, FIG. 2 is an enlarged view of a magnetic coupling portion, FIG. 3 is a sectional view taken along line YY of FIG. 2, and FIG. Another embodiment will be described. FIG. 5 is an enlarged view of the magnetic coupling part, FIG.
FIG. 7 is a sectional view taken along line YY, and FIG. 7 is an enlarged sectional view of a magnetic coupling portion of another embodiment. FIG. 8 is a sectional view showing a conventional vacuum pump device. 21 ... Casing, 22 ... Suction port, 23 ... Discharge port, 24 ...
… Axial flow blades, 25 …… Centrifugal blades, 26 …… Vortex flow blades, 27 …… Rotors, 28 …… Moving blades, 29 …… Static blades, 30 …… Turbo molecular pumps, 31 …… Turbo roughing pumps, 32 ...... Radial magnetic bearing, 33 …… Thrust magnetic bearing, 34 …… Drive motor, 35 ・ ・ ・
… Magnetic coupling.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiro Mase Masahiro Mase 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki Hiritsu Manufacturing Co., Ltd. Mechanical Research Laboratory (72) Yoshihisa Kurita 603 Jinritsu-cho, Tsuchiura-shi, Ibaraki Hiritsu Manufacturing Co., Ltd. At the Tsuchiura Plant (72) Inventor Kazuaki Nakamori 603 Kintate-cho, Tsuchiura-shi, Ibaraki Hiritsu Works Co., Ltd.Tsuchiura Plant (72) Inventor Ichiro Gobe 603 Kintate-cho, Tsuchiura-shi, Ibaraki Hitate Works Co., Ltd. Tsuchiura Plant Of which (56) References: Showa 59-159797 (JP, U)

Claims (7)

[Claims] 1. A vacuum pump device comprising a first pump and a second pump in a casing having a suction port on one side and a discharge port on the other side, wherein a rotating shaft of a rotor of the first pump and the second pump are provided. A vacuum pump device in which the rotating shaft of the rotor of the pump is connected via a magnetic coupling. 2. The turbocharger according to claim 1, wherein the first pump is provided with an axial flow blade in which moving blades provided on the outer periphery of a rotor and stationary blades provided on a casing are alternately arranged. A vacuum pump device characterized by being a molecular pump. 3. The vacuum pump device according to claim 1, wherein the second pump is a turbo roughing pump having a centrifugal blade and a vortex flow rate. 4. A vacuum pump device according to claim 3, wherein the turbo roughing pump is provided with a drive motor. 5. A vacuum pump device comprising a first pump and a second pump in a casing having a suction port on one side and a discharge port on the other side, wherein the first pump is permanently installed outside a rotary shaft of a rotor. A vacuum pump device having a magnet, the second pump having a drive motor, and having a permanent magnet inside a rotating shaft of a rotor. 6. The vacuum pump device according to claim 5, wherein a cover ring is provided on the outer circumference of the permanent magnet provided in the first pump. 7. The vacuum pump device according to claim 5, wherein a plurality of permanent magnets provided in the first and second pumps are radially arranged.