JP3009264B2 - Rotor for multi-stage vacuum pump and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for a multi-stage vacuum pump and a method for manufacturing the same, and more particularly to a process for fixing a plurality of rotors having a machining margin left on a rotating shaft and forming a final outer peripheral shape on the plurality of rotors. TECHNICAL FIELD The present invention relates to a multi-stage vacuum pump rotor formed by applying a method and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, there is known a multistage vacuum pump in which a plurality of rotors having a plurality of rotors are provided adjacent to each other along a rotation axis, and opposed rotors rotate in opposite directions to perform suction and exhaust. ing. The rotors in this vacuum pump rotate without contact with each other and with a slight gap between the rotors facing each other and between the rotor and the casing.

Next, a conventional multi-stage vacuum pump rotor will be described with reference to FIGS. In the rotor for a multi-stage vacuum pump, a plurality of rotors 32 provided in a multi-stage manner at intervals on a rotating shaft 31 are fixed by keys 33. A sleeve 34 and a shim 35 are arranged between the rotors to adjust the distance between the rotors. The rotor for the multi-stage vacuum pump includes a rotor 32 for each stage.
After performing the forming process, the rotary shaft 31 is subjected to keyway processing,
It is manufactured by incorporating the rotor 32 of each stage into the rotating shaft 31. Then, the rotor manufactured in this manner is incorporated in a casing to adjust the gap between the opposed rotors.

[0004]

In the conventional multi-stage vacuum pump rotor described above, the position of the rotor in each stage is determined by the key driving method and the processing accuracy of the outer peripheral shape of the rotor in each stage as shown in FIG. In FIG. 6, the rotors at each stage have a slight phase shift for each stage (only two stages are shown in FIG. 6). Therefore, the clearance between the opposed rotors cannot be reduced, so that the gas flows back through the clearance and the performance of the vacuum pump is reduced. This is because the clearance between the opposed rotors is set assuming that the phases of the rotors at each stage are slightly shifted during assembly, so the clearance between the opposed rotors must be increased inevitably. Because there was no.

The present invention has been made in view of the above points, and an object thereof is to eliminate the phase shift between the rotors of each stage so that the clearance between the opposed rotors is made as small as possible. It is an object of the present invention to provide a rotor for a multi-stage vacuum pump capable of improving the performance of a vacuum pump and a method for manufacturing the same.

[0006]

In order to achieve the above-mentioned object, a multi-stage vacuum pump rotor according to the present invention comprises a plurality of rotors arranged at intervals in the axial direction of a rotating shaft. In the above, a plurality of rotors leaving a machining allowance is fixed to the rotating shaft , and the grinding tool is
Of the rotor of each stage by moving
It is characterized by forming a circumferential shape .

Further, in the method of manufacturing a rotor for a multi-stage vacuum pump according to the present invention, a plurality of rotors having a machining allowance are fixed to a rotating shaft at intervals in the axial direction, and a grinding tool is attached to the rotating shaft.
By moving along the axial direction, the rotor of each stage
Is formed .

According to the rotor for a multi-stage vacuum pump of the present invention having the above-described structure, after a plurality of rotors having a machining allowance are fixed to the rotating shaft, the processing for forming the final outer peripheral shape on the plurality of rotors is simultaneously performed. As a result, there is no phase shift in the rotational direction between the rotors in each stage, and the outer peripheral shape of each stage is located on a straight line along the axial direction, and the rotor manufactured in this manner is incorporated in the casing. By doing
The clearance between the opposing rotors can be made as small as possible. Therefore, gas backflow through the clearance between the opposing rotors is minimized,
The performance of the vacuum pump can be improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multistage vacuum pump rotor and a method of manufacturing the same according to the present invention will be described below with reference to FIGS.

FIG. 1 is a view showing the overall configuration of a vacuum pump incorporating a multistage vacuum pump rotor according to the present invention.
FIG. 2 is a sectional view taken along the line II-II of FIG.

In FIGS. 1 and 2, reference numeral 1 denotes a casing, in which a pair of rotating bodies 2 and 2 are disposed. The rotating body 2 includes a rotating shaft 3 and the rotating shaft 3
And a plurality of rotors 4 arranged along the axial direction. The rotating body 2 is rotatably supported at one end by a bearing 5 and at the other end by a bearing 6. One rotating body 2 is connected to a motor 7. Power is transmitted from one rotating body 2 to the other rotating body 2 by a gear 8 (only one gear is shown in FIG. 1) fixed to the shaft end of the rotating shaft 3, and a pair of rotating bodies The rotors 2 and 2 rotate in directions opposite to each other, and the rotors 4 and 4 opposed to each other with a slight gap rotate in directions opposite to each other to perform suction and exhaust.

The bearing 5 is accommodated in a bearing case 10, and the bearing 6 and the gear 8 are accommodated in a bearing case 11. The bearings 5, 6 and the gear 8 are lubricated with the lubricating oil in the bearing cases 10, 11.

Next, the structure of a multistage vacuum pump rotor according to the present invention and a method of manufacturing the same will be described with reference to FIGS. The rotor for the multi-stage vacuum pump includes a rotating shaft 3 and a plurality of rotors 4 fixed to the rotating shaft 3 by a key 33.
And Further, a sleeve 34 and a shim 35 are provided between the rotors 4 and 4 of the multi-stage, and an interval between the rotors 4 and 4 of each stage is adjusted. As shown in FIG. 3, this multi-stage vacuum pump rotor fixes the rotor 4 of each stage except the machining allowance to the rotating shaft 3 by a key 33, and then performs a grinding process for forming a final outer peripheral shape by a grinding tool 27. At the same time. By moving the grinding tool 27 along the axial direction of the rotating shaft 3, the outer peripheral shape of the rotor 4 at each stage is positioned on a straight line along the axial direction, and as shown in FIG. There is almost no phase shift in the rotation direction of the rotors in the stages.
Therefore, when this multi-stage rotor 4 is incorporated in the casing 1, the clearance between the opposed rotors 4, 4 can be made extremely small. As a result, the backflow of gas from the clearance between the rotors can be minimized, and the performance of the vacuum pump is improved.

As described above, according to this embodiment, since the outer peripheral shape of the rotor is uniform at each stage and the phase of the rotor at each stage is not shifted, the clearance between the opposed rotors is minimized. Can be set, and the performance of the vacuum pump can be improved.

[0014]

As described above, according to the rotor for a multi-stage vacuum pump of the present invention, after the multi-stage rotor having the machining margin left is fixed to the rotating shaft, the final outer peripheral shape is formed. No phase shift occurs in the rotation direction between the rotors, and the outer peripheral shape of each stage is positioned on a straight line along the axial direction. The clearance between the facing rotors can be made as small as possible. Therefore, the backflow of the gas through the clearance between the opposed rotors is minimized, and the performance of the vacuum pump can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the overall configuration of a vacuum pump having a multistage vacuum pump rotor according to the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is an explanatory view showing a manufacturing process of the multistage vacuum pump rotor according to the present invention.

FIG. 4 is a view on arrow IV in FIG. 3;

FIG. 5 is a cross-sectional view of a conventional multi-stage vacuum pump rotor.

FIG. 6 is a view taken in the direction of the arrow VI in FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 casing 2 rotating body 3 rotating shaft 4 rotor 5, 6 bearing 7 motor 8 gear 10, 11 bearing case 27 grinding tool 33 key 34 sleeve 35 shim

──────────────────────────────────────────────────続 き Continuation of the front page (72) Katsuaki Usui 4-2-1, Motofujisawa, Fujisawa-shi, Kanagawa Inside Ebara Research Institute, Inc. (56) References JP-A-3-145594 (JP, A) JP JP-A-48-79389 (JP, A) JP-A-62-277258 (JP, A) JP-A-56-157903 (JP, A) JP-A-52-55173 (JP, Y2) (58) Fields investigated (Int .Cl. ⁷ , DB name) F04C 23/00-29/10 331

Claims (2)

(57) [Claims] 1. A rotor for a multi-stage vacuum pump comprising a plurality of rotors arranged at intervals in an axial direction of a rotating shaft, wherein a plurality of rotors having a machining allowance are fixed to the rotating shaft, and a grinding tool is rotated. Moving along the axis of the shaft
A multi-stage vacuum pump rotor in which the outer peripheral shape of each stage rotor is formed. 2. A plurality of rotors having a machining allowance fixed to a rotating shaft at an interval in the axial direction thereof, and a grinding tool is mounted on the rotating shaft.
Moving along the axial direction of
A method of manufacturing a rotor for a multi-stage vacuum pump, comprising forming an outer peripheral shape of a rotor.