JP2006052728A - Vacuum pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum pump which overcomes the drawbacks of conventional technology and has remarkably high exhaust speed. <P>SOLUTION: The vacuum pump (1) has a flange (2); at least two gas inlet openings (4), at least one gas outlet opening (5); at least two rotor shafts (6), at least one lower part (9) of a housing, an upper part (10) of the housing supporting the flange (2), and a driving means (11) which rotates the rotor shafts (6). Wherein each of the rotor shafts (6) supports each of rotary pump action structure parts (7), and each of the rotary pump action structure parts (7) face each of stationary pump action structure part (8). Then all of the gas inlet openings (4) are inside of the flange (2), and the flange (2) is arranged at the upper part (10) of the common housing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vacuum pump according to the superordinate concept of claim 1.

  Turbo molecular pumps have been used in high vacuum generation for decades. In this pump, the pumping action is generated by a disk having blades, which are mounted alternately on the rotor and the stator. Pumping speed is a standard characteristic variable of the pump and pumping speed is a function of the rotor disk diameter and rotor rotational speed, among others. A few applications require very high pumping speeds. For example, a large volume is exhausted in a particle accelerator. Here, a very large turbomolecular pump is used, whose pumping speed can be 5000 liters / minute. This turbo molecular pump is not technically simple. The problem is, for example, that very high kinetic energy is stored in a rotor with a large diameter, and this high kinetic energy is released when this is not desirable in the error function. Another problem is the complex rotor dynamics, i.e. the mass distribution in a short rotor with a large disk diameter results in similar rotational moments of inertia about different axes. Therefore, the rotating device becomes unstable.

  Starting from this prior art, it is an object of the present invention to provide a vacuum pump having a very high pumping speed which eliminates the above drawbacks. This solution should be more cost effective.

  This problem is solved by the features of claim 1. Other claims represent embodiments of the invention. According to the present invention, the vacuum pump includes one flange, a plurality of gas inflow openings inside the flange, and a plurality of rotor shafts, the rotor shaft supporting the rotary pump action structure portion, and the rotary pump action structure The part has the rotor shaft which cooperates with the fixed pumping structure part to achieve the pumping action.

  By this means, it is possible to achieve a high pumping speed and at the same time to form the rotor disk diameter relative to the rotor length so that the moment of inertia assists stable rotation about the rotor axis. Become. For each rotor shaft, its bearing means and drive means, and its pumping structure part can be standard parts and only a common pump upper part is added as a new structure part, Vacuum pumps can be manufactured very cost-effectively. That is, to assemble, it is only necessary to first assemble a standard part and then push it into the upper part of the common pump. The circular flange shape allows the vacuum pump to be used as a spare for existing vacuum pumps with large pumping speeds. Of course, it is conceivable to adapt the flange to any shape given in advance by the vacuum chamber.

  The form of the vacuum pump according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows in cross-section a vacuum pump according to the invention. The vacuum pump 1 has a flange 2. A plurality of gas inflow openings 4 are present inside the flange 2. One or more gas outlet openings 5 allow the exhaust of the gas to be exhausted. The plurality of rotor shafts 6 each support a rotary pump action structure portion 7. As soon as the rotor shaft 6 is rotated, the rotary pumping structure part 7 cooperates with the fixed pumping structure part 8 to achieve the pumping action. The flange 2 is arranged in the common housing upper part 10. The housing is completed by at least one housing lower part 9. The driving means 11 is used for rotating the rotor shaft 6. In this case, the driving means 11 may be an electric motor, the stator of the electric motor is mounted in the housing, and the rotor elements of the electric motor are fixed to the respective rotor shafts 6. The electric supply necessary for this is performed by the control 12. Bearing means 13 are used to support the rotation of the shaft. The bearing means 13 may be, for example, an oil lubricated rolling bearing or a grease lubricated rolling bearing. Similarly, gas bearings are also conceivable. Up to the specially shaped housing upper part 10, the other said components may be formed from a mass production of a pump having only one rotor at a low pumping speed.

  FIG. 2 shows a possible flange shape. In FIG. 2a, a plurality of gas inlet openings 4 having the same diameter are arranged in a common circular flange. In this case, the diameters of the rotary pumping structure parts fixed on different rotor shafts are the same.

FIG. 2b shows another embodiment in which a plurality of circular gas inlet openings 4 having different diameters are arranged in a common circular flange.
FIG. 2c shows another embodiment in which the common flange is rectangular instead of circular. By this means, the vacuum pump can be optimally adapted to the chamber to be evacuated. Other flange shapes not shown here are also conceivable.

  FIG. 3 shows two different flange shapes in cross-section. In a variant a), the web 14 between the gas inlet openings 4 is drawn and formed, thereby forming a gas inlet 3 to which the gas inlet openings 4 are directly connected. In variant b), the web 14 is pulled up to the height of the flange and ends in the same plane as the flange.

In other embodiments, the rotor shaft 6 is at least partially in its axial length within the common housing upper portion 10 that supports the flange 2.
In other embodiments, multiple controls 12 are provided and the multiple controls 12 are in communication with each other. This communication may be performed, for example, via electrical wiring. This communication is used, for example, to exchange operating parameters such as the rotational speed of the rotor shaft.

  In other embodiments, only one control or multiple controls are configured so that they are used to control the auxiliary pump device. The auxiliary pump device consists of one or more vacuum pumps, at least one of the vacuum pumps compressing the gas to atmospheric pressure. Control includes, for example, setting one or more pumping speeds of the auxiliary pump.

  In other embodiments, the rotor shaft is rotated at an offset rotational speed. That is, in the initial stage where the rotor shaft has not yet reached the final rotational speed, the rotor shafts rotate at different rotational speeds. At each point in time between the start of the vacuum pump where the rotor shaft is stopped and the arrival of the operating rotational speed, the rotor shaft rotates at a different rotational speed. Thereby, it can be avoided that all the rotor shafts rotate at the same rotational speed within the resonance range. Therefore, it is possible to avoid a load due to mutual amplification of vibrations generated by resonance.

  In other embodiments, the rotor shaft is at least partially arranged in parallel. This allows a very cost-effective and simple assembly, since the housing lower part and the packet can be preassembled as a structural group from the rotary pumping structure part and the fixed pumping structure part. Next, the housing upper part 10 with its flange 2 only has to be placed on the pre-assembled structure group.

  This embodiment further contemplates that it is not only the axes of the individual rotor shafts that are parallel to each other. The flange forms a surface and thus a vertical surface perpendicular to the surface. A further possible embodiment occurs when this vertical plane and at least part of the rotor axis are parallel to each other.

  In other embodiments, at least one of the bearing means is a magnetic bearing. In this case, the magnetic bearing may be a passive magnetic bearing or an active magnetic bearing that supports rotation in a radial direction or an axial direction.

  In another embodiment, the rotary pumping structure part 7 and the fixed pumping structure part 8 are formed as vanes so that it is a turbomolecular vacuum pump.

It is sectional drawing of the vacuum pump by this invention. 2a, 2b and 2c are plan views of different flange shapes. a) and b) are sectional views of two flange shapes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum pump 2 Flange 3 Gas inlet 4 Gas inflow opening 5 Gas outflow opening 6 Rotor shaft 7 Rotary pump action structure part 8 Fixed pump action structure part 9 Housing lower part 10 Housing upper part 11 Drive means 12 Control 13 Bearing means 14 Web

Claims (12)

One flange (2), at least two gas inflow openings (4), at least one gas outflow opening (5), and at least two rotor shafts (6), each of the rotor shafts (6) rotating The rotor shaft (6), which supports the pumping structure part (7), each of which faces the fixed pumping structure part (8), and at least one housing lower part (9) And a vacuum pump (1) having a housing upper part (10) supporting the flange (2) and a driving means (11) for rotating the rotor shaft (6),
That all gas inlet openings (4) are present inside the flange (2), and that the flange (2) is located in the upper part of the common housing (10);
A vacuum pump characterized by   2. The vacuum pump according to claim 1, wherein all rotor shafts (6) are arranged at least partly in the axial length in the common housing upper part (10).   3. A vacuum pump according to claim 1, wherein there is one control (12) for electrically operating the drive means (11).   3. The vacuum pump according to claim 1, wherein there are a plurality of controls (12) for electrically operating the drive means (11) and they are in communication with each other.   5. The vacuum pump according to claim 1, wherein the control (12) is used to electrically operate the back pressure vacuum device.   6. The vacuum pump according to claim 1, wherein the diameter of the rotary pumping structure part (7) and the diameter of the fixed pumping structure part (8) of the different rotor shafts (6) are the same.   7. The vacuum pump according to claim 1, wherein the rotor shaft (6) is rotated at an offset rotational speed.   8. A vacuum pump according to claim 1, characterized in that at least part of the axis of the vacuum pump provided by the vertical plane and by the rotor shaft (6) is arranged in parallel.   9. A vacuum pump according to claim 1, wherein at least a part of the bearing means (13) is a magnetic bearing.   10. A vacuum pump according to claim 1, wherein the flange (2) is circular.   The vacuum pump according to claim 1, wherein the vacuum pump is a molecular vacuum pump.   The vacuum pump according to claim 1, wherein the vacuum pump is a turbo molecular vacuum pump.

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