JP2021085343A - Vacuum pump - Google Patents

Abstract

To improve exhaust efficiency of a vacuum pump.SOLUTION: A vacuum pump comprises a rotating body including a rotor shaft, and a rotation support part for rotatably supporting the rotor shaft. The vacuum pump comprises: a suction port for introducing gas into the vacuum pump; a pump operation part for sending the gas introduced from the suction port, in the axial direction of the rotor shaft, on the outside in the radial direction of the rotor shaft; an exhaust flow passage arranged on the downstream side of the gas sent from the pump operation part, and extending in the axial direction and the circumferential direction of the rotor shaft, on the outside in the radial direction of the rotor shaft; and an exhaust port provided at an end part in the axial direction of the exhaust flow passage, for exhausting the gas sent through the exhaust flow passage to the outside, and extending in the circumferential direction of the rotor shaft.SELECTED DRAWING: Figure 1

Description

The present invention relates to an exhaust structure of a vacuum pump.

Vacuum pumps are used to evacuate various vacuum processing equipment such as semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment or analyzers. A turbo molecular pump, which is one of the vacuum pumps, includes a rotating body having a rotor shaft, a rotor and rotor blades, and a rotating support portion having a base and stator blades. When the rotor shaft is rotationally driven by the motor, the rotating body is integrally rotated with respect to the rotation support portion. As a result, the gas in the vacuum processing apparatus is discharged to the outside via the turbo molecular pump, and the inside of the vacuum processing apparatus is evacuated.

In the vacuum pump, the gas introduced from the suction port is sent out in the axial direction of the rotor shaft by the pumping action. Then, the gas sent out by the pumping action is exhausted to the outside through the exhaust port. Patent Document 1 below discloses a vacuum pump provided with an exhaust flow path extending in the radial direction of the rotor shaft below the pump. The exhaust flow path of the vacuum pump of Patent Document 1 is connected to an exhaust port provided on the side surface of the pump.

Japanese Unexamined Patent Publication No. 2018-200042

In the vacuum pump of Patent Document 1, since the exhaust port is provided on the side surface of the pump, the diameter of the exhaust port is relatively small. There is a demand for the diameter of the exhaust port to be as large as possible in order to reduce the exhaust resistance.

An object of the present invention is to improve the exhaust efficiency of a vacuum pump.

A first aspect of the present invention relates to a vacuum pump including a rotating body including a rotor shaft and a rotary support portion that rotatably supports the rotor shaft. The vacuum pump is composed of a suction port for introducing gas into the vacuum pump, a pump working part for sending gas introduced from the suction port in the axial direction of the rotor shaft on the outside in the radial direction of the rotor shaft, and a pump working part. It is arranged on the downstream side of the gas to be sent out, and is provided at the axial end of the exhaust flow path and the exhaust flow path extending in the axial direction and the circumferential direction of the rotor shaft on the outside in the radial direction of the rotor shaft. It is provided with an exhaust port extending in the circumferential direction of the rotor shaft for exhausting the gas sent out through the rotor shaft to the outside.

According to the present invention, the exhaust efficiency of the vacuum pump can be improved.

FIG. 1 is a side sectional view of the vacuum pump according to the embodiment. FIG. 2 is a sectional view taken along line II-II of the vacuum pump shown in FIG. FIG. 3 is a bottom view of the vacuum pump according to the embodiment.

(1) Overall Configuration of Vacuum Pump Hereinafter, the vacuum pump according to the embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view of the vacuum pump 100 according to the embodiment. As shown in FIG. 1, the vacuum pump 100 according to the embodiment is a turbo molecular pump. The vacuum pump 100 includes a rotating body 3 having a rotor shaft 30, a rotor 31, a rotor blade 33, and a rotor cylindrical portion 35, and a rotating support portion 2 having a base 21, a casing 22, and a stator 25. When the rotor shaft 30 is rotationally driven by the motor 43, the rotating body 3 is integrally rotated with respect to the rotation support portion 2.

As shown in FIG. 1, the rotor shaft 30 is rotationally driven around the axis 100a. In the following description, the direction in which the axial center 100a extends is referred to as the axial direction of the rotor shaft 30 or the axial direction of the vacuum pump 100. The direction extending perpendicular to the axis 100a is called the radial direction of the rotor shaft 30 or the radial direction of the vacuum pump 100. The direction extending in the circumferential direction about the axis 100a is called the circumferential direction of the rotor shaft 30 or the circumferential direction of the vacuum pump 100. Further, in the following description, the vertical direction in FIG. 1 will be described as the vertical direction of the vacuum pump 100.

The base 21 included in the rotation support portion 2 constitutes a lower portion of the rotation support portion 2 of the vacuum pump 100 and a peripheral portion of the axis 100a. The base 21 is made of metal and has a substantially cylindrical shape. The casing 22 included in the rotation support portion 2 is arranged on the upper part of the base 21 and constitutes the outer wall of the upper part of the vacuum pump 100. The casing 22 is made of metal and has a substantially cylindrical shape. A space extending in the vertical direction is formed in the central portion in the radial direction of the base 21, and the rotor shaft 30 is arranged in the space. A suction port 100b is provided on the upper part of the casing 22. The gas sucked from the vacuum processing apparatus to be vacuum-processed is introduced into the vacuum pump 100 from the suction port 100b.

The motor 43 includes a motor stator and a motor rotor, and is rotationally driven around an axis 100a. The motor stator is fixed to the inner peripheral surface of the base 21. The motor rotor is fixed to the outer peripheral surface of the rotor shaft 30. The motor 43 is connected to a control unit and a power supply unit via a power line (not shown). The motor 43 is rotationally driven by the drive of the control unit.

A rotor 31 that rotates integrally with the rotor shaft 30 is attached to a position above the motor 43 on the outer circumference of the rotor shaft 30. The rotor 31 has a substantially tubular shape. A plurality of rotor blades 33 extending outward in the radial direction are provided on the outer periphery of the rotor 31. In the embodiment shown in FIG. 1, eight stages of rotor blades 33 are arranged in the vertical direction.

A plurality of stator blades 23 extending inward in the radial direction are provided on the inner peripheral surface of the casing 22. In the embodiment shown in FIG. 1, eight stages of stator blades 23 are arranged in the vertical direction. The turbo pump TP is configured by alternately arranging the plurality of rotor blades 33 and the stator blades 23 with a gap in the vertical direction. The flow path R1 is formed by a region that passes through the plurality of rotor blades 33 and the plurality of stator blades 23 in the vertical direction.

A rotor cylindrical portion 35 is provided below the rotor 31. The rotor cylindrical portion 35 extends downward (in the axial direction of the rotor shaft 30) from the lower portion of the rotor 31. A stator 25 is arranged on the outer side of the rotor cylindrical portion 35 in the radial direction. The stator 25 is fixed to the base 21. The flow path R2 is formed by a minute gap formed between the rotor cylindrical portion 35 and the stator 25. A thread groove (not shown) is provided in either the rotor cylindrical portion 35 or the stator 25. The Holwick pump HP is composed of the rotor cylindrical portion 35 and the stator 25. The lower end of the Hewlett pump HP, that is, the lower end of the flow path R2, constitutes the exhaust portion P1 of the Hewlett pump HP. As described above, in the present embodiment, the Holwick pump HP is provided downstream of the turbo pump TP.

The base 21 is provided with bearings 41a and 41b that support the rotor shaft 30. The bearing 41a is arranged above the motor 43. The bearing 41b is arranged below the motor 43. The bearings 41a and 41b are, for example, rolling bearings, and rotatably support the upper portion and the lower portion of the rotor shaft 30. In the present embodiment, the bearings 41a and 41b are ball bearings, but the embodiment is not limited to this. The bearings 41a and 41b may be other rolling bearings such as roller bearings.

The base 21 is provided with magnetic bearings 42a and 42b that support the rotor shaft 30. The upper portion of the rotor shaft 30 is rotatably and non-contactly supported by the base 21 by a magnetic bearing 42a. The lower portion of the rotor shaft 30 is rotatably and non-contactly supported by the base 21 by a magnetic bearing 42b.

A circular rotor disk 36 is provided at the lower end of the rotor shaft 30 in a plan view (when viewed from the extending direction of the axis 100a). A magnetic bearing 42c is provided on the base 21 so as to sandwich the rotor disk 36 from above and below. The electromagnets of the magnetic bearing 42c are arranged above and below the rotor disk 36 with a gap. By attracting the rotor disk 36 by the magnetic bearing 42c, the rotor shaft 30 floats in the axial direction.

(2) Exhaust structure of vacuum pump Next, the exhaust structure of the gas sent out by the turbo pump TP and the Holwick pump HP will be described. FIG. 2 is a sectional view taken along line II-II of the vacuum pump 100 shown in FIG. A cylindrical exhaust flow path R3 is formed on the base 21. As shown in FIG. 1, the exhaust flow path R3 is provided on the downstream side of the Hewlett pump HP. The gas sent out from the lower end of the flow path R2, that is, the exhaust portion P1 of the Hewlett pump HP, flows downward through the exhaust flow path R3. The exhaust flow path R3 extends linearly from the exhaust portion P1 to the bottom surface 100c of the vacuum pump 100.

FIG. 3 is a bottom view of the vacuum pump 100. Three exhaust ports 27a, 27b, and 27c are provided on the bottom surface 100c of the vacuum pump 100. The exhaust ports 27a, 27b, and 27c have an arc shape extending in the circumferential direction of the axis 100a. The exhaust ports 27a, 27b, 27c are arranged at equal intervals in the circumferential direction of the axis 100a. The exhaust ports 27a, 27b, and 27c are all connected to the exhaust flow path R3. That is, the gas flowing through the cylindrical exhaust flow path R3 is exhausted to the outside of the vacuum pump 100 via any of the exhaust ports 27a, 27b, and 27c.

(3) Operation of the vacuum pump and flow of exhaust gas The operation of the vacuum pump 100 configured as described above will be described. When the motor 43 is rotationally driven, the rotor shaft 30 fixed to the motor rotor rotates. As a result, the rotor 31 and the plurality of rotor blades 33 rotate integrally with the rotor shaft 30. As a result, the plurality of rotor blades 33 rotate relative to the plurality of stator blades 23, and the turbo pump TP is driven.

By the action of the turbo pump TP, gas is sucked from the suction port 100b provided at the upper end of the vacuum pump 100. The suction port 100b is connected to a vacuum processing device (not shown), and the gas in the vacuum processing device is introduced into the vacuum pump 100 via the suction port 100b. As shown in the flow path R1 of FIG. 1, the gas introduced from the suction port 100b passes between the plurality of rotor blades 33 and the plurality of stator blades 23, and is sent downward while being compressed.

The gas sent downward through the plurality of rotor blades 33 and the plurality of stator blades 23 flows into the upstream side of the Holwick pump HP. Due to the rotation of the motor 43, the rotor cylindrical portion 35 rotates integrally with the rotor 31. As a result, the rotor cylindrical portion 35 rotates relative to the stator 25, and the Holwick pump HP is driven. Due to the action of the Holweck pump HP, the compressed gas is sent out downstream in the flow path R2 formed in the gap between the rotor cylindrical portion 35 and the stator 25. The gas sent downward through the flow path R2 flows from the exhaust unit P1 into the exhaust flow path R3 provided on the base 21.

As described above, in the vacuum pump 100 of the present embodiment, the exhaust flow path R3 is arranged on the downstream side of the gas delivered by the turbo pump TP and the Holwick pump HP. The exhaust flow path R3 extends outward in the radial direction of the rotor shaft 30 in the axial direction and the circumferential direction of the rotor shaft 30. Further, the vacuum pump 100 is provided at the lower end of the exhaust flow path R3 in the axial direction, and includes exhaust ports 27a, 27b, 27c for exhausting the gas sent out through the exhaust flow path R3 to the outside. The exhaust ports 27a, 27b, 27c extend in the circumferential direction of the rotor shaft.

As a result, the gas delivered from the turbo pump TP and the Holwick pump HP is exhausted through the exhaust flow path R3 extending in the circumferential direction and the exhaust ports 27a, 27b, 27c, so that the exhaust efficiency is improved. When the exhaust port is attached to the side surface of the vacuum pump, the diameter of the exhaust port becomes smaller and the exhaust resistance becomes larger. However, in the present embodiment, the exhaust ports 27a, 27b, 27c having a large diameter are attached to the bottom surface 100c of the vacuum pump 100. Therefore, the exhaust resistance can be reduced. Conventionally, an exhaust port having a diameter of, for example, about 40 mm is provided on the side surface of the vacuum pump. On the other hand, in the present embodiment, for example, if the pump diameter of the vacuum pump 100 is 300 mm, the total opening areas of the exhaust ports 27a, 27b, and 27c are equivalent to those of a circular exhaust port having a diameter of about 100 mm. The area can be secured.

Further, the exhaust flow path R3 is configured to extend in the coaxial direction with the rotation axis (axis center 100a) of the rotating body 3 over the entire area from the exhaust portion P1 to the exhaust ports 27a, 27b, 27c. As a result, the gas sent out by the rotating body 3 is smoothly exhausted from the exhaust ports 27a, 27b, 27c without causing stagnation in the entire flow path leading to the exhaust ports 27a, 27b, 27c.

Further, in the vacuum pump 100 of the present embodiment, when viewed from the axial direction of the rotor shaft 30, the regions of the exhaust ports 27a, 27b, 27c overlap with the exhaust portion P1 of the gas sent out by the Holwick pump HP. That is, when the vacuum pump 100 is viewed from the bottom surface 100c side, the exhaust ports 27a, 27b, 27c and the exhaust portion P1 overlap. As a result, the gas sent out from the turbo pump TP and the Holweck pump HP is sent out straight in the axial direction of the vacuum pump 100, so that the exhaust efficiency is improved.

Further, in the vacuum pump 100 of the present embodiment, the exhaust flow path R3 has a cylindrical shape. As a result, as shown in FIG. 1, the exhaust flow path R3 extends so as to be continuous with the flow path R1 and the flow path R2 in the axial direction. That is, in the vacuum pump 100, the flow paths R1, the flow paths R2, and the exhaust flow path R3 extend in a cylindrical shape in the axial direction of the rotor shaft 30 as a whole. As a result, the gas sent out by the rotating body 3 is exhausted from the exhaust ports 27a, 27b, 27c without stagnation without causing a pressure difference in the circumferential direction.

When stagnation occurs in the gas flow in the exhaust flow path, a pressure difference occurs in the exhaust flow path. At this time, unnecessary products may be deposited due to the liquefaction or solidification of the gas in the portion where the pressure is increased. In the vacuum pump 100 of the present embodiment, the pressure difference generated in the exhaust flow path R3 is reduced, so that the accumulation of products can be prevented.

Further, in the vacuum pump 100 of the present embodiment, the exhaust ports 27a, 27b, 27c have an arc shape. Specifically, the exhaust ports 27a, 27b, and 27c have an arc shape having a diameter close to that of the cylindrical exhaust flow path R3. As a result, the gas that is sent out from the exhaust flow path R3 without stagnation is exhausted as it is at the exhaust ports 27a, 27b, 27c without being given resistance.

Further, in the present embodiment, the exhaust ports 27a, 27b, 27c have the same shape, and the exhaust ports 27a, 27b, 27c are arranged at equal intervals in the circumferential direction of the rotor shaft 30. ing. As a result, at the exhaust ports 27a, 27b, and 27c, the pressure of the exhaust gas in the circumferential direction of the rotor shaft 30 is not biased in the circumferential direction. The gas flowing through the exhaust flow path R3 is exhausted from the exhaust ports 27a, 27b, 27c without stagnation without causing a pressure difference.

(4) Connection of exhaust pipe As shown in FIG. 1, the exhaust pipe 5 is connected to the bottom surface 100c of the vacuum pump 100. The exhaust pipe 5 has a substantially cylindrical shape in the present embodiment. The exhaust pipe 5 has a diameter including all of the exhaust ports 27a, 27b, and 27c of the vacuum pump 100. That is, all the gases exhausted from the exhaust ports 27a, 27b, 27c are exhausted in one exhaust pipe 5. In this way, since the exhaust pipe 5 having a large diameter is connected to the downstream side from the exhaust ports 27a, 27b, 27c, the gas flowing through the exhaust flow path R3 and the exhaust ports 27a, 27b, 27c is external with a small exhaust resistance. Is exhausted to.

(5) Correspondence between Each Component of Claim and Each Element of Embodiment Hereinafter, an example of correspondence between each component of claim and each element of embodiment will be described. Not limited to. In the above embodiment, the turbo pump TP or the Holwick pump HP is an example of the pump working part. In the above embodiment, the exhaust ports 27a, 27b, 27c are examples of a plurality of openings.

As each component of the claim, various elements having the structure or function described in the claim can also be used.

(6) Other Embodiments In the above embodiment, the case where the vacuum pump 100 is a turbo molecular pump is shown, but the present invention is not limited to this. For example, the present invention can be applied to a vacuum pump having only a drag pump (thread groove pump) such as a Siegburn pump or a Holweck pump, or a vacuum pump consisting of a combination of a turbo molecular pump and a drag pump. Is.

In the above embodiment, the exhaust flow path R3 has a cylindrical shape extending over the entire circumference in the circumferential direction of the rotor shaft 30. In another embodiment, the exhaust flow path R3 may be divided in the circumferential direction. For example, it may have an arc shape such as three or four when viewed from the axial direction. For example, an opening having the same shape as the exhaust ports 27a, 27b, 27c when viewed from the axial direction may extend in the vertical direction in the axial direction to form the exhaust flow path R3. When the exhaust flow path R3 is divided into a plurality of parts, the exhaust port may be connected over the entire circumference of the rotor shaft 30 in the circumferential direction without being divided.

In the above embodiment, the exhaust ports 27a, 27b, 27c have an arc shape, but the shapes of the exhaust ports 27a, 27b, 27c are not limited to the arc shape. For example, the exhaust ports 27a, 27b, 27c may have a rectangle that includes the opening shown in FIG.

In the above embodiment, the exhaust flow path R3 is provided on the outer side in the radial direction of the rotor shaft 30 when viewed from the axial direction of the vacuum pump 100. Further, in the above embodiment, the exhaust flow path R3 is provided on the outer side in the radial direction of the magnetic bearing 42c when viewed from the axial direction of the vacuum pump 100. As a result, the flow paths R1, the flow path R2, and the exhaust flow path R3 are arranged substantially in a straight line in the axial direction, so that the exhaust resistance of the gas to be sent out can be further reduced.

The specific configuration of the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the gist of the invention.

(7) Aspects It will be understood by those skilled in the art that the plurality of exemplary embodiments described above are specific examples of the following embodiments.

(Section 1) The vacuum pump according to one aspect is
A vacuum pump including a rotating body including a rotor shaft and a rotary support portion that rotatably supports the rotor shaft.
A suction port for introducing gas into the vacuum pump and
On the outside in the radial direction of the rotor shaft, a pump acting portion that sends out the gas introduced from the suction port in the axial direction of the rotor shaft, and
An exhaust flow path that is arranged on the downstream side of the gas sent out by the pumping unit and extends in the axial direction and the circumferential direction of the rotor shaft on the outer side in the radial direction of the rotor shaft.
An exhaust port extending in the circumferential direction of the rotor shaft, which is provided at the axial end of the exhaust flow path and exhausts the gas sent out through the exhaust flow path to the outside.
To be equipped.

Since the gas sent out from the pumping unit is exhausted from the exhaust passage and the exhaust port extending in the circumferential direction, the exhaust efficiency is improved.

(Item 2) In the vacuum pump according to item 1,
When viewed from the axial direction of the rotor shaft, the region of the exhaust port and the exhaust portion of the pump acting portion may overlap.

Since the gas sent out from the pump working part is sent out straight in the axial direction of the vacuum pump, the exhaust efficiency is improved.

(Section 3)
In the vacuum pump according to the first or second paragraph,
The exhaust flow path may have a cylindrical shape.

The gas sent out by the rotating body is exhausted from the exhaust port without stagnation without causing a pressure difference in the circumferential direction.

(Item 4) In the vacuum pump according to any one of items 1 to 3,
The exhaust port may have an arc shape.

The gas that is sent out from the exhaust flow path without stagnation is exhausted as it is at the exhaust port without being given resistance.

(Section 5) In the vacuum pump according to any one of paragraphs 1 to 4,
The exhaust port may be divided into a plurality of openings.

A large opening area can be secured while maintaining the structure that supports the base of the vacuum pump.

(Section 6) In the vacuum pump according to paragraph 5,
The plurality of openings may be arranged at equal intervals in the circumferential direction of the rotor shaft.

In the circumferential direction of the rotor shaft, the pressure of the exhausted gas is not biased in the circumferential direction. The gas flowing through the exhaust flow path is exhausted from the exhaust port without stagnation without causing a pressure difference.

(Section 7) In the vacuum pump according to the fifth or sixth paragraph,
The plurality of openings may be connected to a single exhaust pipe.

The gas exhausted to the outside from the plurality of openings is smoothly exhausted without causing resistance.

(Item 8) In the vacuum pump according to any one of items 1 to 7,
With respect to the axial direction of the rotor shaft, the suction port may be provided on one end surface of the vacuum pump, and the exhaust port may be provided on the other end surface.

2 ... Rotational support, 21 ... Base, 22 ... Casing, 23 ... Stator wing, 25 ... Stator, 27a, 27b, 27c ... Exhaust port, 3 ... Rotating body, 30 ... Rotor shaft, 31 ... Rotor, 33 ... Rotor wing , 35 ... rotor cylindrical part, 41a / 41b ... bearing, 42a / 42b / 42c ... magnetic bearing, 43 ... motor, 100 ... vacuum pump, TP ... turbo pump, HP ... Holweck pump, R1 / R2 ... flow path, R3 ... Exhaust flow path

Claims (8)

A vacuum pump including a rotating body including a rotor shaft and a rotary support portion that rotatably supports the rotor shaft.
A suction port for introducing gas into the vacuum pump and
On the outside in the radial direction of the rotor shaft, a pump acting portion that sends out the gas introduced from the suction port in the axial direction of the rotor shaft, and
An exhaust flow path that is arranged on the downstream side of the gas sent out by the pumping unit and extends in the axial direction and the circumferential direction of the rotor shaft on the outer side in the radial direction of the rotor shaft.
An exhaust port extending in the circumferential direction of the rotor shaft, which is provided at the axial end of the exhaust flow path and exhausts the gas sent out through the exhaust flow path to the outside.
A vacuum pump equipped with. The vacuum pump according to claim 1, wherein the region of the exhaust port and the exhaust portion of the pump acting portion overlap when viewed from the axial direction of the rotor shaft. The vacuum pump according to claim 1 or 2, wherein the exhaust flow path has a cylindrical shape. The vacuum pump according to any one of claims 1 to 3, wherein the exhaust port has an arc shape. The vacuum pump according to any one of claims 1 to 4, wherein the exhaust port is divided into a plurality of openings. The vacuum pump according to claim 5, wherein the plurality of openings are arranged at equal intervals in the circumferential direction of the rotor shaft. The vacuum pump according to claim 5 or 6, wherein the plurality of openings are connected to a single exhaust pipe. The vacuum pump according to any one of claims 1 to 7, wherein the suction port is provided on one end surface of the vacuum pump and the exhaust port is provided on the other end surface in the axial direction of the rotor shaft.

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