JPH01393A - vacuum pump equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum pump device, and particularly to a vacuum pump suitable for obtaining a clean ultra-high vacuum in semiconductor manufacturing equipment, nuclear fusion equipment, and the like.

[Conventional technology]

A conventional vacuum pump device, as shown in FIG. 8, is composed of 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 includes a casing 21 having a suction port 22 connected to an ultra-high vacuum container on one side and a discharge port 23 on the other side, a rotor 27 disposed inside the casing 21, and a rotor 27 on the outer periphery of the rotor 27. The rotor blade 28 is provided, the rotor blade 29 is provided on the inner surface of the casing 21, and the drive motor 34 that rotates the rotor 1lill 21A is provided, and the #JJ't28 and the rotor blade 29 are arranged alternately. rotor 27 and dynamic ff
An ultra-high vacuum can be obtained by transporting gas molecules from the suction port 22 to the discharge port 23 on the low vacuum side by the rotation of the E 28. Further, one end of a flexible tube 11 is connected to the discharge port 23 of the turbo molecular pump 30 via a quick coupling IOA, and the roughing pump 31 is connected to the other end of the flexible tube 11 via a quick coupling IOB. ing. Also, due to the backflow of oil from the roughing pump 31, the turbo molecular pump 30
Alternatively, a trap 12 is interposed between the roughing pump 31 and the flexible tube 11 in order to prevent the ultra-high vacuum container from being contaminated. As described in Japanese Patent Application Laid-Open No. 60-204997, this type of device has a spiral groove pump section and a centrifugal pump section, and the rotors of these pump sections are mounted on a common rotating shaft. There is a compound vacuum pump that can pump from atmospheric pressure to ultra-high vacuum with a single pump.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology requires a large installation space because it is necessary to provide a roughing pump in addition to the turbo-molecular pump.

Also, since a roughing pump that uses oil is used, it is difficult to obtain a clean ultra-high vacuum. Further, a drive source for driving the turbo molecular pump and the roughing pump is required, and a power supply system is also required for each. Furthermore, roughing pumps such as rotary pumps generate vibrations, so when using turbomolecular pumps in semiconductor manufacturing equipment or other equipment that dislikes vibrations, it is necessary to prevent vibrations from being transmitted to the turbomolecular pumps. When the turbo-molecular pump section and the roughing pump section are integrated into a single shaft as described above, heat is generated in the rotor in the viscous flow region of the roughing pump section, and heat is generated in the rotor in the molecular flow region of the turbo-molecular pump section. If not cooled, the temperature would reach approximately 200°C, causing problems in terms of strength and exhaust performance. In addition, there was an interlude that even if the casing was cooled in the turbomolecular pump section, heat transfer was performed by radiation, which had little cooling effect and caused the rotor to reach a high temperature, resulting in poor performance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a summer air pump device that can reduce the installation space, reduce the vibration area, and provide an ultra-high vacuum.

[Means for solving problems]

The above purpose is to provide a vacuum pump device that includes a first pump and a second pump in a casing that has a suction port on one side and a discharge port on the other side. This is achieved by connecting the rotating shafts of the rotors via magnetic coupling.

[Effect]

Since the first and second pumps are provided with pump elements for evacuating the molecular flow region, intermediate flow region, and viscous flow region within one casing, the installation space can be reduced. In addition, the drive shafts of the two rotors are connected non-contact by magnetic bearings, which reduces vibration and prevents the heat generated by the second pump section, which has the drive motor, from being transmitted to the first pump section, increasing strength and reliability. can be improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows a sectional view of a vacuum pump device according to the invention, with a casing having an inlet 22 on the one hand and an outlet 23 on the other, with the casing 2 inside the axial flow blade 24. Centrifugal blade 25.
A swirl vane 26 is provided. In IIJI style, 24 is
The turbo molecular pump 30 is constructed by alternately arranging a plurality of rotor blades 28 provided on the outer periphery of a rotor 27 and a plurality of rotor blades 29 provided on the inner periphery of the casing 21. In the turbo roughing pump 31, a centrifugal blade 25 and a swirl 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 and is configured to rotate at high speed. To connect the turbo molecular pump 30 and the turbo roughing pump 31, cylindrical magnetic couplings 35A and 35B made of permanent magnets are provided at the ends of each rotor, and the rotation of the turbo roughing pump 31 is transferred to the turbo molecular pump 30. I'm telling you. Here, since the turbo roughing pump 31 is used in a viscous flow region, it generates heat, but by cooling the casing 21, the rotor does not reach a high temperature. However, the turbo-molecular pump 30 is in a molecular flow region, and even if the casing is cooled, the rotor has little cooling effect due to heat transfer by radiation, resulting in a high temperature, which also poses a problem in terms of strength. Therefore, it is necessary to block the heat conduction from the turbo roughing pump section, but by providing a magnetic coupling of permanent magnets at the shaft end of the turbo molecular pump rotor and the shaft end of the turbo roughing pump rotor, the drive motor can Since the rotor rotates, the heat generated by the turbo roughing pump 31 is prevented from being transmitted to the turbo molecular pump 30.

Strength reliability can be improved. Furthermore, since the turbo roughing pump 31 has a culmability of 10-δTorr from atmospheric pressure, it requires a driving torque and a motor of 3 to 5 kW, but the turbo molecular pump is in the molecular flow region and requires only about 30 to 50 W, so it is difficult to drive. At this time, the turbo molecular pump section is at atmospheric pressure and a driving torque is required, so even if the turbo roughing pump rotates, the turbo molecular pump section does not rotate, but when the turbo roughing pump rotates and the degree of vacuum increases, the turbo molecular pump section The pump also rotates at the same speed as the roughing pump. As a result, an ultra-wide vacuum pump capable of operating from atmospheric pressure to ultra-high vacuum can be obtained.

FIG. 2 shows an enlarged view of the magnetic coupling 35 section. A plurality of permanent magnets 35B are arranged inside the drive side rotor shaft 27B, a plurality of permanent magnets 35A are arranged outside the non-drive side rotor shaft 27A, and a cover ring 40 is placed around the outer periphery of the permanent magnet 35A to prevent it from scattering due to centrifugal force. It is set in.

These transmit the rotation of the drive shaft to the counter-drive shaft. FIG. 3 shows a YY sectional view of FIG. 2.

Furthermore, a method of providing a cylindrical ring made of a hysteresis material such as maraging steel in place of the permanent magnet 35A is also considered. Maraging steel has high strength, is resistant to centrifugal force, and can be rotated at high speeds.

FIG. 4 shows a roughing pump 31 showing another embodiment of the present invention.
A 30-stage turbomolecular pump is arranged upstream of the stage, and a radial bearing 3 is installed in an inner cylindrical casing 38 in the casing 21.
Turbo molecular pump 30 by 2A and thrust bearing 33A
The steps are supported.

Upper part of turbo roughing pump 31 stage and turbo molecular pump 30
Even if a plurality of permanent magnets are arranged radially at the bottom of the step, the same effect as the embodiment shown in FIG. 1 can be obtained. Figures 5 and 6
The figure shows a magnetic coupling part. Permanent magnets 35A are provided at the ends of the drive side rotor shaft 27B and the non-drive side rotor shaft 27A.

A similar effect can be obtained by arranging a plurality of 35B radially as shown in FIG.

FIG. 7 shows another embodiment of the invention. Small size.

In order to reduce the weight and perform high-speed rotation, it is effective to shorten the axial length, and by shortening the length, the critical speed of the rotor shaft increases and high-speed rotation becomes possible. As shown in FIG. 7, by providing a disk 39 made of a high-strength hysteresis material such as maraging steel in place of the permanent magnet, the axial length and weight can be reduced. This makes maraging steel a high-strength material that can be rotated at high speeds.

〔Effect of the invention〕

According to the present invention, the pump element for evacuating the turbo molecular pump part and the turbo roughing pump part is arranged in one casing, and the pump element can be evacuated from an ultra-high vacuum to atmospheric pressure, thereby reducing the installation space. A clean ultra-light vacuum can be obtained6.Furthermore, by connecting the rotor drive shafts of each pump element with magnetic coupling, only one drive source is required. Since each pump section is connected by magnetic coupling in a non-contact manner, there is no heat conduction, which prevents the turbomolecular pump section from increasing in temperature, thereby improving strength and reliability. Furthermore, the drive motor of the turbo roughing pump is 3 to 5k.
Compared to w, the 1ψ movement of a turbomolecular pump requires 30 to 50 W, so a low-torque coupling such as a magnetic coupling is required, so a magnetic coupling is advantageous6.

[Brief explanation of the drawing]

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 section, Fig. 3 is a YY sectional view of Fig. 2, and Fig. 4 shows another embodiment. FIG. 5 is an enlarged view of the magnetic coupling portion, FIG. 6 is a Y-Y sectional view, and FIG. 7 is an enlarged sectional view of the 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 blade, 25... Centrifugal blade, 26...
... Vortex blade, 27 ... Rotor, 28 ... Moving blade, 29
...Stator blade, 30...Turbo molecular pump, 31...
Turbo roughing pump. 32... Radial magnetic bearing, 33... Thrust magnetic bearing, 34... Drive motor, 35... Magnetic coupling.

Claims (1)

[Claims] 1. In 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, the rotating shaft of the rotor of the first pump and A vacuum pump device characterized in that the rotation shaft of the rotor of the second pump is connected via a magnetic coupling. 2. In claim 1, the first pump is a turbo-molecular pump equipped with axial flow blades formed by alternately arranging rotor blades provided on the outer periphery of the rotor and stationary blades provided in the casing. A vacuum pump device characterized by: 3. The vacuum pump device according to claim 1, wherein the second pump is a turbo roughing pump equipped with centrifugal blades and a vortex flow rate. 4. The vacuum pump device according to claim 3, wherein the turbo roughing pump is provided with a drive motor. 5. In 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, the first pump has a permanent magnet outside the rotating shaft of the rotor. The vacuum pump device is characterized in that the second pump is equipped with a drive motor and has a permanent magnet inside the rotating shaft of the rotor. 6. The vacuum pump device according to claim 5, characterized in that a cover ring is provided around the outer periphery 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 arranged radially.