KR20210045321A - Vacuum pump apparatus - Google Patents

Abstract

An objective of the present invention is to provide a vacuum pump device capable of preventing a decrease in the temperature of a pump casing due to heat conduction and maintaining the inside of a rotor chamber at a high temperature. The vacuum pump device according to the present invention includes: a pump casing (2) which has a rotor chamber (1) therein; a pump rotor (5) which is disposed in the rotor chamber (1); a rotating shaft (7) to which the pump rotor (5) is fixed; an electric motor (8) which is connected to the rotating shaft (7); a side cover (10A) which forms the end surface of the rotor chamber (1); a housing structure (16) which is located on the outside of the side cover (10A) with respect to the axial direction of the rotating shaft (7); and a heat insulating body (25A) which is located between the pump casing (2) and the housing structure (16).

Description

Vacuum pump device {VACUUM PUMP APPARATUS}

TECHNICAL FIELD The present invention relates to a vacuum pump device, and in particular, to a vacuum pump device suitably used for exhausting process gases used in manufacturing semiconductor devices, liquid crystals, LEDs, solar cells, and the like.

In a manufacturing process for manufacturing semiconductor devices, liquid crystal panels, LEDs, solar cells, and the like, a process gas is introduced into a process chamber to perform various treatments such as etching treatment and CVD treatment. The process gas introduced into the process chamber is exhausted by the vacuum pump device. In general, the vacuum pump device used in these manufacturing processes requiring high cleanliness is a so-called dry vacuum pump device that does not use oil in the gas flow path. As a representative example of such a dry vacuum pump device, it is a positive displacement vacuum pump device that transfers gas by rotating a pair of pump rotors arranged in a rotor chamber in opposite directions to each other.

The process gas may contain by-products having a high sublimation temperature. When the temperature in the rotor chamber of the vacuum pump device is low, by-products are solidified in the rotor chamber and may be deposited on the inner surface of the pump rotor or pump casing. The solidified by-products inhibit the rotation of the pump rotor, causing a decrease in the speed of the pump rotor or, in the worst case, stopping the operation of the vacuum pump device. Therefore, in order to prevent solidification of by-products, a heater is attached to the outer surface of the pump casing to heat the rotor chamber.

On the other hand, the electric motor that drives the pump rotor and the gear fixed to the rotation shaft of the pump rotor need to be cooled. Therefore, the above-described vacuum pump device is usually provided with a cooling system for cooling an electric motor and a gear. The cooling system is configured to cool the electric motor and gears, for example, by circulating a cooling liquid through a cooling pipe provided in a motor housing for accommodating the electric motor and a cooling pipe provided in a gear housing for accommodating a gear. With such a cooling system, overheating of the electric motor and gear can be prevented, and stable operation of the vacuum pump device can be achieved.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2003-35290 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-251470

However, the heat of the pump casing heated by the heater is likely to be transferred to the motor housing and gear housing having a low temperature. As a result of such heat conduction, the temperature of the rotor chamber in the pump casing may decrease. Particularly, since the end face of the rotor chamber is at a position close to the motor housing or gear housing having a low temperature, the temperature of the end face of the rotor chamber is liable to decrease. As a result, there is a concern that by-products contained in the process gas solidify in the rotor chamber. As one of the countermeasures, it is possible to consider using a heater of high output, but such a heater requires more power, and thus energy saving operation of the vacuum pump device cannot be achieved.

Thus, the present invention provides a vacuum pump device capable of preventing a temperature drop of a pump casing due to heat conduction and maintaining a high temperature inside a rotor chamber.

In one aspect, a pump casing having a rotor chamber therein, a pump rotor disposed in the rotor chamber, a rotating shaft to which the pump rotor is fixed, an electric motor connected to the rotating shaft, and a side forming an end surface of the rotor chamber A vacuum pump device is provided that includes a cover, a housing structure positioned outside the side cover in the axial direction of the rotation shaft, and a heat insulating body positioned between the pump casing and the housing structure.

In one aspect, the heat insulating body includes a heat insulating structure sandwiched between the side cover and the housing structure.

In one aspect, the side cover has a hollow structure having a space therein, and the heat insulator includes a gas layer present in the space of the side cover.

In one aspect, the heat insulating body includes a heat insulating member disposed in the side cover.

In one aspect, the side cover has an inner side cover forming an end surface of the rotor chamber, and an outer side cover positioned outside the inner side cover in the axial direction, and the heat insulating member includes the inner side cover. It is sandwiched between the side cover and the outer side cover.

In one aspect, the cross-sectional area of the heat insulating member is smaller than the cross-sectional area of the side cover.

In one aspect, a side heater disposed in the side cover is further provided.

The heat insulator disposed between the pump casing and the housing structure can reduce heat conduction from the pump casing to the housing structure. Therefore, the inside of the rotor chamber can be maintained at a high temperature.

1 is a cross-sectional view showing an embodiment of a vacuum pump device.
2 is an exploded perspective view showing a side cover, a heat insulating body, and a gear housing.
3 is a cross-sectional view showing another embodiment of the vacuum pump device.
4 is an enlarged cross-sectional view of the side cover shown in FIG. 3.
5 is a cross-sectional view showing another embodiment of the vacuum pump device.
6 is an exploded perspective view showing a side cover and a plurality of heat insulating members shown in FIG. 5.
7 is a cross-sectional view showing still another embodiment of the vacuum pump device.
8 is a cross-sectional view showing still another embodiment of the vacuum pump device.
9 is a cross-sectional view showing an embodiment in which a heater is attached to an outer surface of a pump casing.
10 is a cross-sectional view showing an embodiment in which a side heater is embedded in a side cover.
11 is a cross-sectional view taken along line AA of FIG. 10.
12 is a diagram showing an embodiment in which a plurality of side heaters are disposed in a side cover.
13 is a cross-sectional view showing an embodiment of a vacuum pump device including two heat insulators shown in FIG. 8 and side heaters shown in FIG. 10.
14 is a cross-sectional view taken along line BB shown in FIG. 13.
15 is a diagram showing an embodiment in which a plurality of side heaters are disposed in a side cover.
Fig. 16 is a cross-sectional view showing an embodiment of a vacuum pump device including both a side heater embedded in a side cover and a heater attached to an outer surface of a pump casing.
17 is a cross-sectional view showing an embodiment of a vacuum pump device including a multistage pump rotor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is a cross-sectional view showing an embodiment of a vacuum pump device. The vacuum pump device of the embodiment described below is a positive displacement vacuum pump device. In particular, the vacuum pump device shown in Fig. 1 is a so-called dry vacuum pump device that does not use oil in the gas flow path. The dry vacuum pump apparatus can be suitably used for a semiconductor device manufacturing apparatus requiring high cleanliness since vaporized oil does not flow to the upstream side.

1, the vacuum pump device includes a pump casing 2 having a rotor chamber 1 therein, a pump rotor 5 disposed in the rotor chamber 1, and a pump rotor 5 It has a fixed rotating shaft 7 and an electric motor 8 connected to the rotating shaft 7. The pump rotor 5 and the rotation shaft 7 may be an integral structure. In Fig. 1, only one pump rotor 5, one rotation shaft 7, and one electric motor 8 are drawn, but a pair of pump rotors 5 are arranged in the rotor chamber 1, and a pair It is fixed to each of the rotating shaft (7). The pair of electric motors 8 are respectively connected to the pair of rotation shafts 7.

The pump rotor 5 of this embodiment is a root pump rotor, but the type of the pump rotor 5 is not limited to this embodiment. In one embodiment, the pump rotor 5 may be a screw type pump rotor. Moreover, although the pump rotor 5 of this embodiment is a single-stage pump rotor, in one embodiment, the pump rotor 5 may be a multi-stage pump rotor.

The vacuum pump device further includes side covers 10A and 10B positioned outside the pump casing 2 in the axial direction of the rotation shaft 7. The side covers 10A and 10B are provided on both sides of the pump casing 2 and are connected to the pump casing 2. In this embodiment, the side covers 10A and 10B are fixed to the end surface of the pump casing 2 by screws (not shown). In one embodiment, the side covers 10A and 10B may be integrated with the pump casing 2.

The rotor chamber 1 is formed by an inner surface of the pump casing 2 and an inner surface of the side covers 10A and 10B. The pump casing 2 has an intake port 2a and an exhaust port 2b. The intake port 2a is connected to a chamber (not shown) filled with a gas to be transferred. In one example, the intake port 2a is connected to a process chamber of an apparatus for manufacturing a semiconductor device, and the vacuum pump apparatus is used for exhausting the process gas introduced into the process chamber.

The vacuum pump device further includes a bearing housing 12, a motor housing 14, and a gear housing 16 as housing structures positioned outside the side covers 10A and 10B in the axial direction of the rotation shaft 7. We have. The side cover 10A is located between the pump casing 2 and the gear housing 16, and the side cover 10B is located between the pump casing 2 and the bearing housing 12. The bearing housing 12 is located between the side cover 10B and the motor housing 14.

The rotating shaft 7 is rotatably supported by a bearing 17 disposed in the bearing housing 12 and a bearing 18 disposed in the gear housing 16. The motor housing 14 houses the motor rotor 8A and the motor stator 8B of the electric motor 8 therein. The bearing housing 12, the motor housing 14, and the gear housing 16 are examples of the housing structure, and the housing structure is not limited to this embodiment.

Two electric motors 8 (only one electric motor 8 is shown in Fig. 1) rotates in opposite directions synchronously by a motor driver (not shown), and a pair of rotation shafts 7 and a pair of pump rotors It is possible to rotate in the opposite direction in synchronization with (5). When the pump rotor 5 rotates by the electric motor 8, gas is sucked into the pump casing 2 from the intake port 2a. The gas is conveyed from the intake port 2a to the exhaust port 2b by the rotating pump rotor 5.

Inside the gear housing 16, a pair of gears 20 meshing with each other are arranged. In addition, only one gear 20 is drawn in FIG. 1. As described above, since the pair of pump rotors 5 are rotated synchronously by the two electric motors 8, the role of the gear 20 is the synchronous rotation of the pump rotor 5 due to an unexpected external factor. It is to prevent the outbreak of the body.

A cooling pipe 21 is buried in the gear housing 16. Similarly, the cooling pipe 22 is embedded in the motor housing 14. The cooling pipe 21 extends over the entire peripheral wall of the gear housing 16, and the cooling pipe 22 extends over the entire peripheral wall of the motor housing 14. The cooling pipe 21 and the cooling pipe 22 are connected to a cooling liquid supply source (not shown). The cooling liquid is supplied to the cooling pipe 21 and the cooling pipe 22 from a cooling liquid supply source. The cooling liquid flowing through the cooling pipe 21 cools the gear housing 16, thereby cooling the gear 20 and the bearing 18 disposed in the gear housing 16. The cooling liquid flowing through the cooling pipe 22 cools the motor housing 14 and the bearing housing 12, whereby the motor 8 disposed in the motor housing 14 and the motor 8 disposed in the bearing housing 12 The bearing 17 can be cooled.

Between the side cover 10A and the gear housing (housing structure) 16, the heat insulating structure 25A which is a heat insulating material is sandwiched. The side cover 10A and the gear housing 16 are separated from each other (not in contact with each other), and the heat insulating structure 25A is in contact with both the side cover 10A and the gear housing 16. This heat insulating structure 25A is located between the pump casing 2 and the gear housing 16, and has a function of reducing heat transfer to the gear housing 16 from the pump casing 2 through the side cover 10A. Have.

Some process gases handled by the vacuum pump device of the present embodiment contain by-products that solidify with a decrease in temperature. During operation of the vacuum pump device, the process gas is compressed in the process of being conveyed by the pump rotor 5 from the intake port 2a to the exhaust port 2b. Therefore, the inside of the rotor chamber 1 becomes high temperature by the heat of compression of the process gas. The heat insulation structure 25A can reduce heat transfer from the pump casing 2 to the gear housing 16 through the side cover 10A, and can maintain the inside of the rotor chamber 1 at a high temperature. In particular, while cooling the gear housing 16 with the coolant flowing through the cooling pipe 21, the heat insulating structure 25A can maintain the inside of the rotor chamber 1 at a high temperature.

The heat insulating structure 25A has a lower thermal conductivity than the side cover 10A. More specifically, the heat insulating structure 25A is made of a material having a lower thermal conductivity than the material constituting the side cover 10A. In this embodiment, the pump casing 2 and the side covers 10A and 10B forming the rotor chamber 1 are made of cast iron. The bearing housing 12, the motor housing 14, and the gear housing 16 are made of aluminum. The heat insulating structure 25A is made of a resin having a lower thermal conductivity than the material of the side cover 10A. In one example, the heat insulating structure 25A is made of polytetrafluoroethylene (PTFE), which is a kind of fluororesin. Polytetrafluoroethylene (PTFE) has a lower thermal conductivity than cast iron and has a property that can withstand high temperatures. However, if a material having a lower thermal conductivity than the material of the side cover 10A, the material of the heat insulating structure 25A may be a metal such as stainless steel, titanium, or spherical graphite austenite cast iron (niresist).

Another housing structure such as a bearing housing may be disposed between the side cover 10A and the gear housing 16. In this case, the heat insulating structure 25A is sandwiched between the side cover 10A and the housing structure.

2 is an exploded perspective view showing the side cover 10A, the heat insulating structure 25A, and the gear housing 16. As shown in FIG. As shown in Fig. 2, the heat insulating structure 25A has an annular shape and is arranged to surround the outer peripheral surface of the rotating shaft 7 (see Fig. 1). The side cover 10A has a through hole 27 through which the rotation shaft 7 passes. The through hole 27 communicates with the rotor chamber 1. The heat insulating structure 25A is disposed around these through holes 27. The inner surface of the heat insulating structure 25A is in contact with the outer surface of the side cover 10A, and the outer surface of the heat insulating structure 25A is in contact with the inner end surface of the gear housing 16. The heat insulating structure 25A has a seamless annular shape, and the heat insulating structure 25A also functions as a seal sealing the gap between the side cover 10A and the gear housing 16.

Similarly, between the side cover 10B and the bearing housing (housing structure) 12, the heat insulating structure 25B is interposed. That is, the side cover 10B and the bearing housing 12 are separated from each other (not in contact with each other), and the heat insulating structure 25B is in contact with both the side cover 10B and the bearing housing 12. This heat insulation structure 25B is located between the pump casing 2 and the bearing housing 12, and has a function of reducing heat transfer from the pump casing 2 to the bearing housing 12 through the side cover 10B. Have. In particular, while cooling the motor housing 14 and the bearing housing 12 with the cooling liquid flowing through the cooling pipe 22, the heat insulating structure 25B can maintain the inside of the rotor chamber 1 at a high temperature.

The heat insulation structure 25B has a seamless annular shape, and the heat insulation structure 25B also functions as a seal sealing the gap between the side cover 10B and the bearing housing 12. That is, the inner surface of the heat insulating structure 25B is in contact with the outer surface of the side cover 10B, and the outer surface of the heat insulating structure 25B is in contact with the inner end surface of the bearing housing 12. The heat insulating structure 25B has a lower thermal conductivity than the side cover 10B. More specifically, the heat insulating structure 25B is made of a material having a lower thermal conductivity than the material constituting the side cover 10B. Since the structure of the heat insulating structure 25B is the same as that of the heat insulating structure 25A, a duplicate description thereof is omitted.

Another housing structure may be disposed between the side cover 10B and the bearing housing 12. In this case, the heat insulating structure 25B is sandwiched between the side cover 10B and the housing structure. In addition, the bearing housing 12 may not be provided between the side cover 10B and the motor housing 14 in some cases. In such a case, the heat insulating structure 25B is sandwiched between the side cover 10B and the motor housing 14.

3 is a cross-sectional view showing another embodiment of the vacuum pump device. The configuration of the present embodiment, which is not specifically described, is the same as the embodiment described with reference to FIG. 1, and therefore, a redundant description thereof is omitted. In this embodiment, the gas layer 29A as a heat insulating material is provided in the side cover 10A. The heat insulating structures 25A and 25B are not provided.

The gas layer 29A is located between the pump casing 2 and the gear housing 16, and has a lower thermal conductivity than the side cover 10A. Accordingly, the base layer 29A has a function of reducing heat transfer from the pump casing 2 to the gear housing 16 through the side cover 10A. The side cover 10A has a hollow structure having a space therein. The heat insulator of this embodiment is the gas layer 29A existing in the space of the side cover 10A.

4 is an enlarged cross-sectional view of the side cover 10A shown in FIG. 3. The side cover 10A includes an inner side cover 31A forming an end surface of the rotor chamber 1 and an outer side cover positioned outside the inner side cover 31A in the axial direction of the rotation shaft 7 ( 32A). A recess 33 is formed on the outer surface of the inner side cover 31A. The concave portion 33 may be formed on the inner surface of the outer side cover 32A, or may be formed on both the outer surface of the inner side cover 31A and the inner surface of the outer side cover 32A.

When the outer surface of the inner side cover 31A and the inner surface of the outer side cover 32A face each other, a space 34 is formed in the side cover 10A by the recess 33 and the inner surface of the outer side cover 32A. . This space 34 expands outward in the radial direction from the through hole 27 through which the rotation shaft 7 passes. The space 34 communicates with the through hole 27, and the through hole 27 communicates with the rotor chamber 1. An annular seal 35 such as an O-ring is disposed outside the concave portion 33 in the radial direction. The recess 33 is surrounded by a seal 35. This seal 35 seals a gap between the outer surface of the inner side cover 31A and the inner surface of the outer side cover 32A.

The gas layer 29A is formed in the space 34. Gases generally have a lower thermal conductivity than solids. In particular, since the space 34 communicates with the rotor chamber 1, during the operation of the vacuum pump device, the gas layer 29A is formed of a gas having a pressure lower than atmospheric pressure. The gas constituting the gas layer 29A is air, N ₂ , or a gas existing in the rotor chamber 1, or a mixture thereof. The low pressure gas has a lower thermal conductivity than the atmospheric pressure gas.

The base layer 29A has a lower thermal conductivity than the side cover 10A. Therefore, the gas layer 29A located in the side cover 10A can reduce the heat transfer from the pump casing 2 to the gear housing (housing structure) 16. In particular, while cooling the gear housing 16 with the cooling liquid flowing through the cooling pipe 21, the gas layer 29A can maintain the inside of the rotor chamber 1 at a high temperature. Further, since the base layer 29A substantially reduces the end surface of the side cover 10A, it contributes to reduction of heat transfer from the pump casing 2 to the gear housing (housing structure) 16.

As shown in Fig. 3, a gas layer 29B as a heat insulator is similarly provided in the other side cover 10B. The side cover 10B has a hollow structure having a space therein. The side cover 10B includes an inner side cover 31B forming an end surface of the rotor chamber 1 and an outer side cover positioned outside the inner side cover 31B in the axial direction of the rotation shaft 7 ( 32B). The configuration of the side cover 10B is substantially the same as that of the side cover 10A. Since the description of the side cover 10A with reference to FIGS. 3 and 4 is applicable to the side cover 10B, other detailed descriptions of the side cover 10B will be omitted.

The gas layer 29B formed in the side cover 10B is located between the pump casing 2 and the bearing housing 12. The base layer 29B has a lower thermal conductivity than the side cover 10B. Accordingly, the base layer 29B has a function of reducing heat transfer from the pump casing 2 to the bearing housing 12 through the side cover 10B. In particular, while cooling the motor housing 14 and the bearing housing 12 with the cooling liquid flowing through the cooling pipe 22, the gas layer 29B can maintain the inside of the rotor chamber 1 at a high temperature. Further, the base layer 29B contributes to a reduction in heat transfer from the pump casing 2 to the bearing housing 12 because the end face of the side cover 10B is substantially reduced.

5 is a cross-sectional view showing another embodiment of the vacuum pump device. The configuration of the present embodiment, which is not specifically described, is the same as the embodiment described with reference to FIG. 3, and therefore, a redundant description thereof is omitted. In this embodiment, a plurality of heat insulating members 41A and 42A as heat insulating bodies are provided in the side cover 10A. The side cover 10A includes an inner side cover 31A forming an end surface of the rotor chamber 1 and an outer side cover positioned outside the inner side cover 31A in the axial direction of the rotation shaft 7 ( 32A).

The plurality of heat insulating members 41A and 42A are sandwiched between the inner side cover 31A and the outer side cover 32A. That is, the inner side cover 31A and the outer side cover 32A are separated from each other (not in contact with each other), and the plurality of heat insulating members 41A and 42A are the inner side cover 31A and the outer side cover 32A. They are in contact with both. The plurality of heat insulating members 41A and 42A as this heat insulating body are located between the pump casing 2 and the gear housing 16, and have a lower thermal conductivity than the side cover 10A. Accordingly, the plurality of heat insulating members 41A and 42A have a function of reducing heat transfer from the pump casing 2 to the gear housing 16 through the side cover 10A.

6 is an exploded perspective view showing a side cover 10A and a plurality of heat insulating members 41A and 42A shown in FIG. 5. The plurality of heat-insulating members 41A, 42A include a heat-insulating plate 41A having two through holes 45 through which the rotating shaft 7 passes, and a plurality of heat-insulating spacers 42A disposed around the heat-insulating plate 41A. Includes. The concave portion 47 is formed on the outer surface of the inner side cover 31A, and the heat insulating plate 41A is disposed in the concave portion 47. In one embodiment, the concave portion 47 is formed on the inner surface of the outer side cover 32A, and the heat insulating plate 41A may be disposed in the concave portion 47 of the outer side cover 32A. The heat insulating plate 41A of this embodiment is a single structure, but may be separated into a plurality of structures. Seals (not shown) such as O-rings are disposed between the heat insulating plate 41A and the inner side cover 31A, and between the heat insulating plate 41A and the outer side cover 32A.

The heat insulating plate 41A and the heat insulating spacer 42A have a lower thermal conductivity than the side cover 10A. Therefore, the heat insulating plate 41A and the heat insulating spacer 42A reduce the heat transfer from the pump casing 2 to the gear housing 16 through the side cover 10A, and keep the inside of the rotor chamber 1 at a high temperature. I can. In particular, while cooling the gear housing 16 with the cooling liquid flowing through the cooling pipe 21 (see FIG. 5), the heat insulating plate 41A and the heat insulating spacer 42A can maintain the inside of the rotor chamber 1 at a high temperature.

The heat insulating plate 41A and the heat insulating spacer 42A are made of a material having a lower thermal conductivity than the material constituting the side cover 10A. In this embodiment, the pump casing 2 and the side covers 10A and 10B constituting the rotor chamber 1 are made of cast iron. The heat-insulating plate 41A and the heat-insulating spacer 42A are made of metal such as stainless steel, titanium, or spherical graphite-based austenite cast iron (niresist) having a lower thermal conductivity than the material of the side cover 10A. In this embodiment, the heat-insulating plate 41A and the heat-insulating spacer 42A are made of stainless steel. Stainless steel has a lower thermal conductivity than cast iron. Further, stainless steel has high mechanical rigidity, and high dimensional accuracy can be ensured at the time of assembling the vacuum pump device. However, as long as the thermal conductivity is lower than that of the material of the side cover 10A and has high mechanical rigidity, the material of the heat insulating plate 41A and/or the heat insulating spacer 42A may be another material such as resin.

The total cross-sectional area of the heat-insulating plate 41A and the heat-insulating spacer 42A is smaller than the cross-sectional area of the side cover 10A. Therefore, the heat-insulating plate 41A and the heat-insulating spacer 42A with a small thermal conductivity and cross-sectional area contribute to reduction of heat transfer from the pump casing 2 to the gear housing 16.

As shown in Fig. 5, in the other side cover 10B, a plurality of heat insulating members 41B and 42B as heat insulating bodies, that is, a heat insulating plate 41B and a plurality of heat insulating spacers 42B, are equally installed. have. The side cover 10B includes an inner side cover 31B forming an end surface of the rotor chamber 1 and an outer side cover positioned outside the inner side cover 31B in the axial direction of the rotation shaft 7 ( 32B).

The configuration and arrangement of the side cover 10B, the heat insulation plate 41B, and the plurality of heat insulation spacers 42B are substantially the same as the side cover 10A, the heat insulation plate 41A, and the plurality of heat insulation spacers 42A. Do. The description of the side cover 10A, the heat insulating plate 41A, and the plurality of heat insulating spacers 42A with reference to Figs. 5 and 6 is the side cover 10B, the heat insulating plate 41B, and the plurality of heat insulating spacers 42B. ), so other detailed descriptions thereof are omitted.

The heat insulating plate 41B and the heat insulating spacer 42B formed in the side cover 10B are located between the pump casing 2 and the bearing housing 12. The heat insulating plate 41B and the heat insulating spacer 42B have a lower thermal conductivity than the side cover 10B. Therefore, the heat insulating plate 41B and the heat insulating spacer 42B have a function of reducing heat transfer from the pump casing 2 to the bearing housing 12 through the side cover 10B. In particular, while cooling the motor housing 14 and the bearing housing 12 with the cooling liquid flowing through the cooling pipe 22, the heat insulating plate 41B and the heat insulating spacer 42B can maintain the inside of the rotor chamber 1 at a high temperature. .

The total cross-sectional area of the heat-insulating plate 41B and the heat-insulating spacer 42B is smaller than the cross-sectional area of the side cover 10B. Therefore, the heat-insulating plate 41B and the heat-insulating spacer 42B with a small thermal conductivity and cross-sectional area contribute to reduction of heat transfer from the pump casing 2 to the bearing housing 12.

7 is a cross-sectional view showing still another embodiment of the vacuum pump device. The configuration of the present embodiment, which is not specifically described, is the same as the embodiment described with reference to Figs. 1 to 4, and thus redundant descriptions thereof are omitted. In this embodiment, as shown in FIG. 7, the vacuum pump device includes both heat insulating structures 25A and 25B and gas layers 29A and 29B. According to this embodiment, the inside of the rotor chamber 1 can be maintained at a high temperature by the heat insulating structures 25A and 25B and the base layers 29A and 29B.

8 is a cross-sectional view showing still another embodiment of the vacuum pump device. The configuration of this embodiment, which is not specifically described, is the same as the embodiment described with reference to Figs. 1, 2, 5, and 6, and thus redundant descriptions thereof will be omitted. In this embodiment, as shown in FIG. 8, the vacuum pump device includes both heat-insulating structures 25A and 25B and heat-insulating members 41A, 42A, 41B, and 42B. According to this embodiment, a double heat insulating body is constituted by the heat insulating structures 25A and 25B and the heat insulating members 41A, 42A, 41B, and 42B, and the inside of the rotor chamber 1 can be kept at a high temperature.

In order to keep the rotor chamber 1 at a higher temperature, a heater 50 may be provided on the outer surface of the pump casing 2 as shown in FIG. 9. The type of the heater 50 is not particularly limited, but, for example, an electric heater is attached to the outer surface of the pump casing 2. Since the pump casing 2 is heated by the heater 50 and the rotor chamber 1 is maintained at a high temperature, solidification of by-products contained in the process gas can be reliably prevented. Further, since the heat insulating structures 25A and 25B have a function of retaining heat in the rotor chamber 1, electric power required for the operation of the heater 50 can be reduced.

The embodiment shown in FIG. 9 is a structure in which the heater 50 is attached to the outer surface of the pump casing 2 of the vacuum pump device of the embodiment shown in FIG. 1, but the heater 50 shown in FIG. It can also be applied to each of the embodiments shown in FIGS. 3, 5, 7, and 8.

10 is a cross-sectional view showing an embodiment in which side heaters 55A and 55B are embedded in the side covers 10A and 10B, and FIG. 11 is a cross-sectional view taken along line A-A of FIG. 10. The configuration of this embodiment, which is not specifically described, is the same as the embodiment described with reference to Figs. 1 and 2, and therefore, a redundant description thereof will be omitted.

The side cover 10A includes an inner side cover 31A forming an end surface of the rotor chamber 1 and an outer side cover positioned outside the inner side cover 31A in the axial direction of the rotation shaft 7 ( 32A). The side heater 55A is disposed between the inner side cover 31A and the outer side cover 32A.

11, the outer surface of the inner side cover 31A has a groove 56 surrounding the through hole 27 into which the rotation shaft 7 is inserted, and the side heater 55A has a groove 56 ) Is installed within. The side heater 55A is disposed so as to surround the through hole 27. The side heater 55A is an annular heater disposed so as to surround the rotation shaft 7 passing through the through hole 27. The kind of side heater 55A is not particularly limited, but a sheath heater, which is a kind of electric heater, can be used for the side heater 55A.

Since the side cover 10A is located closer to the gear housing 16 where the cooling pipe 21 is installed than the pump casing 2, the temperature of the side cover 10A is lowered compared to the pump casing 2. easy. According to the embodiment shown in FIGS. 10 and 11, a side heater 55A is provided between the pump casing 2 and the gear housing (housing structure) 16. Since the side heater 55A can heat the side cover 10A itself, the inside of the rotor chamber 1 in which the end surface is formed by the side cover 10A can be made high temperature.

The specific configuration for arranging the side heater 55A in the side cover 10A is not limited to the embodiment shown in Figs. 10 and 11. For example, a side cover 10A having a hole in which the side heater 55A is disposed may be formed by casting, and the side heater 55A may be inserted into the hole. In this case, the side cover 10A does not need to be separated into the inner side cover 31A and the outer side cover 32A.

In one embodiment, as shown in Fig. 12, a plurality of side heaters 55A may be disposed in the side cover 10A. In the embodiment shown in Fig. 12, two side heaters 55A extending in parallel are disposed in the side cover 10A. Three or more side heaters 55A may be disposed.

As shown in Fig. 10, the side heater 55B is also disposed in the side cover 10B. The side cover 10B includes an inner side cover 31B forming an end surface of the rotor chamber 1 and an outer side cover positioned outside the inner side cover 31B in the axial direction of the rotation shaft 7 ( 32B). The outer surface of the inner side cover 31B has a groove (not shown), and the side heater 55B is installed in the groove. The side heater 55B is an annular heater disposed so as to surround the rotation shaft 7. The description of the side heater 55A and the side cover 10A with reference to FIGS. 10 to 12 can also be applied to the side heater 55B and the side cover 10B, so that the side heater 55B and the side cover 10B Other explanations of are omitted.

The side heaters 55A and 55B shown in FIGS. 10 to 12 can be applied to each of the embodiments shown in FIGS. 3, 5, 7, and 8.

FIG. 13 is an embodiment of a vacuum pump device including the heat insulating structures 25A and 25B and the heat insulating members 41A, 42A, 41B, and 42B shown in FIG. 8, and the side heaters 55A and 55B shown in FIG. 10 It is a cross-sectional view showing the form. 14 is a cross-sectional view taken along line B-B shown in FIG. 13. As shown in Fig. 14, the side heater 55A is disposed so as to surround the heat insulating plate 41A. Although not shown, the side heater 55B is similarly arranged so as to surround the heat insulating plate 41B. As shown in Fig. 15, a plurality of side heaters 55A may be provided. Similarly, a plurality of side heaters 55B may be provided.

According to the embodiment shown in Figs. 13 to 15, the interior of the rotor chamber 1 is reduced by a combination of the double heat insulators 25A, 25B, 41A, 42A, 41B, 42B and the side heaters 55A, 55B. It can be kept at high temperature. In addition, electric power required for operation of the side heaters 55A and 55B can be reduced.

As shown in Fig. 16, side heaters 55A and 55B and heater 50 attached to the outer surface of the pump casing 2 may be combined. The combination of the side heaters 55A and 55B and the heater 50 can be applied to each of the above-described embodiments.

In each of the embodiments described so far, heat insulators are disposed on both sides of the rotor chamber 1, but the present invention is not limited to such an arrangement. In one embodiment, the heat insulator may be disposed only on one side of the rotor chamber 1. For example, when the cooling pipe 21 is not provided in the gear housing 16, the heat insulating structure 25A and/or the heat insulating members 41A and 42A may be omitted. Similarly, the above-described side heaters 55A and 55B are disposed on both sides of the rotor chamber 1, but in one embodiment, the side heater 55A or the side heater 55B is provided on only one side of the rotor chamber 1 May be placed.

17 is a cross-sectional view showing an embodiment of a vacuum pump device including a multistage pump rotor. The configuration of this embodiment, which is not specifically described, is the same as that of the embodiment shown in Fig. 13, and therefore, a redundant description thereof is omitted. The vacuum pump device shown in FIG. 17 is equipped with a multistage pump rotor 5 provided with a plurality of rotors 5a to 5e. The intake port 2a is located at the gear side end of the pump casing 2, and the exhaust port 2b is located at the motor side end of the pump casing 2. With the rotation of the multi-stage pump rotor 5, gas is conveyed from the intake port 2a to the exhaust port 2b while being compressed. The heat of compression generated when the gas is compressed is highest in the vicinity of the exhaust port 2b. Therefore, the temperature on the exhaust side of the rotor chamber 1 is higher than the temperature on the intake side of the rotor chamber 1.

Depending on the type of process gas, some contain by-products with a relatively low sublimation temperature. Such by-products are likely to be solidified on the intake side of the rotor chamber 1, while hardly solidifying on the exhaust side of the rotor chamber 1. Therefore, in such a case, as shown in Fig. 17, the vacuum pump device is only between the gear housing 16 and the pump casing 2, the heat insulating structure 25A and/or the heat insulating members 41A, 42A, and / Or you may have the side heater (55A).

The above-described embodiment has been described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention pertains to practice the present invention. Various modifications of the above-described embodiments can naturally be achieved by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be interpreted in the widest scope according to the technical idea defined by the claims.

1: rotor chamber 2: pump casing
2a: intake port 2b: exhaust port
5: pump rotor 7: rotary shaft
8: electric motor 8A: motor rotor
8B: motor stator 10A, 10B: side cover
12: bearing housing 14: motor housing
16: gear housing 17: bearing
18: bearing 20: gear
21: cooling pipe 22: cooling pipe
25A, 25B: heat insulation structure 27: through hole
29A, 29B: gas layer 31A, 31B: inner side cover
32A, 32B: outer side cover 33: recess
34: space 35: seal
41A, 41B: Insulation member (insulation plate)
42A, 42B: Insulation member (insulation spacer)
45: through hole 47: recess
50: heater 55A, 55B: side heater
56: home

Claims (7)

A pump casing having a rotor chamber inside,
A pump rotor disposed in the rotor chamber,
A rotating shaft on which the pump rotor is fixed,
An electric motor connected to the rotating shaft,
A side cover forming an end surface of the rotor chamber,
A housing structure located outside the side cover in the axial direction of the rotation shaft,
Insulator positioned between the pump casing and the housing structure
A vacuum pump device comprising a. The vacuum pump device according to claim 1, wherein the heat insulating body includes a heat insulating structure sandwiched between the side cover and the housing structure. The method according to claim 1 or 2, wherein the side cover has a hollow structure having a space therein,
The heat insulator includes a gas layer present in the space of the side cover. The vacuum pump device according to claim 1 or 2, wherein the heat insulating member includes a heat insulating member disposed in the side cover. The method according to claim 4, wherein the side cover has an inner side cover forming an end surface of the rotor chamber, and an outer side cover positioned outside the inner side cover in the axial direction,
The heat insulating member is a vacuum pump device sandwiched between the inner side cover and the outer side cover. The vacuum pump device according to claim 5, wherein a cross-sectional area of the heat insulating member is smaller than a cross-sectional area of the side cover. The vacuum pump device according to claim 1 or 2, further comprising a side heater disposed in the side cover.

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