TW202138679A - Vacuum pump apparatus - Google Patents

Abstract

An objective of the present invention is to provide a vacuum pump apparatus capable of maintaining the inside of a rotor chamber at a high temperature. The vacuum pump apparatus includes: a pump housing (2) having a rotor chamber (1) inside; a pump rotor(s) arranged in the rotor chamber (1); a rotating shaft (7) to which the pump rotor (5) is fixed; an electric motor (8) connected to the rotating shaft (7); a side cover (10A) forming an end surface of the rotor chamber (1); and a side heater (55A) arranged inside the side cover (10A).

Description

Vacuum pump device

The present invention relates to a vacuum pump device, and in particular, to a vacuum pump device suitable for the purpose of exhausting process gases used in the manufacture of semiconductor elements, liquid crystals, LEDs, solar cells, and the like.

In the manufacturing process for manufacturing semiconductor elements, liquid crystal panels, LEDs, solar cells, etc., process gases are introduced into the process chamber to perform various processes such as etching treatment and CVD treatment. The process gas introduced into the process chamber is exhausted by a vacuum pump device. Generally, vacuum pump devices used in these manufacturing processes that require high cleanliness are so-called dry vacuum pump devices that do not use oil in the gas flow path. As a representative example of such a dry vacuum pump device, there is a positive displacement vacuum pump device that rotates a pair of pump rotors arranged in a rotor chamber in opposite directions to each other to transfer gas.

The process gas sometimes contains by-products with a higher sublimation temperature. If the temperature in the rotor chamber of the vacuum pump device is low, the by-products may solidify in the rotor chamber and accumulate on the inner surface of the pump rotor and the pump casing. The solidified by-products hinder the rotation of the pump rotor, causing the speed of the pump rotor to decrease, and in the worst case, cause the operation of the vacuum pump device to stop. Therefore, in order to prevent solidification of by-products, a heater is installed on the outer surface of the pump casing to heat the rotor chamber.

On the other hand, it is necessary to cool the motor that drives the pump rotor and the gear fixed to the rotating shaft of the pump rotor. Therefore, the above-mentioned vacuum pump device generally includes a cooling system for cooling the electric motor and the gear. The cooling system is configured, for example, to cool the motor and the gear by circulating a cooling liquid through a cooling pipe provided in a motor housing that houses the electric motor and through a cooling pipe provided in a gear housing that houses the gears. With such a cooling system, it is possible to prevent overheating of the motor and gears, and to achieve stable operation of the vacuum pump device.

(Prior technical literature)

(Patent Document)

Patent Document 1: Japanese Patent Application Publication No. 2003-35290

Patent Document 2: JP 2012-251470 A

However, the heat of the pump housing heated by the heater is easily transferred to the lower temperature motor housing and gear housing. As a result of such heat conduction, the temperature of the rotor chamber in the pump housing sometimes decreases. In particular, since the end surface of the rotor chamber is located close to the lower temperature of the motor housing or the gear housing, the temperature of the end surface of the rotor chamber is likely to decrease. As a result, the by-products contained in the process gas may solidify in the rotor chamber. As one of the countermeasures, the use of a high-output heater is considered. However, such a heater requires more power and cannot achieve energy-saving operation of the vacuum pump device.

Here, the present invention provides a vacuum pump device capable of maintaining the inside of the rotor chamber of the pump housing at a relatively high temperature.

In one aspect, a vacuum pump device is provided, including: a pump housing with a rotor chamber inside; a pump rotor arranged in the rotor chamber; a rotating shaft in which the pump rotor is fixed; and a motor connected to the rotating shaft Connection; side cover, which forms the end surface of the aforementioned rotor chamber; and the side heater, which is arranged in the aforementioned side cover.

In one aspect, the side heater is configured to surround the rotating shaft.

In one aspect, the side cover includes: an inner side cover forming an end surface of the rotor chamber, and an outer side cover located outside the inner side cover in the axial direction of the rotating shaft; the side heater is arranged on the inner side Between the side cover and the aforementioned outer side cover.

The side heater can heat the side cover itself, and therefore can raise the temperature in the rotor chamber where the end surface is formed by the side cover.

1: Rotor chamber

2: pump housing

2a: suction port

2b: Exhaust port

5: Pump rotor

7: Rotation axis

8: Electric motor

8A: Motor rotor

8B: Motor stator

10A, 10B: side cover

12: Bearing shell

14: Motor housing

16: gear housing

17: Bearing

18: Bearing

20: Gear

21, 22: Cooling pipe

25A, 25B: Thermal insulation structure

27, 45: Through hole

31A, 31B: inner side cover

32A, 32B: Outer side cover

41A, 41B: Heat insulation member (heat insulation board)

42A, 42B: Insulation member (insulation liner)

47: sunken

55A, 55B: side heater

56: Slot

58: Hole

Fig. 1 is a cross-sectional view showing an embodiment of the vacuum pump device.

Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 1.

Fig. 3 is a diagram showing an embodiment in which a plurality of side heaters are arranged in a side cover.

Fig. 4(a) is a diagram showing another embodiment in which the side heater is arranged in the side cover, and Fig. 4(b) is a cross-sectional view taken along the line B-B of Fig. 4(a).

Fig. 5(a) is a diagram showing another embodiment in which the side heater is arranged in the side cover, and Fig. 5(b) is a cross-sectional view taken along the line C-C of Fig. 5(a).

Fig. 6(a) is a diagram showing another embodiment in which the side heater is arranged in the side cover, and Fig. 6(b) is a cross-sectional view taken along the line D-D of Fig. 6(a).

Fig. 7(a) is a diagram showing another embodiment in which the side heater is arranged in the side cover, and Fig. 7(b) is a cross-sectional view taken along the line E-E of Fig. 7(a).

Fig. 8(a) is a diagram showing another embodiment in which the side heater is arranged in the side cover, and Fig. 8(b) is a cross-sectional view taken along the line F-F of Fig. 8(a).

Fig. 9 is a cross-sectional view showing another embodiment of the vacuum pump device.

Fig. 10 is a cross-sectional view showing another embodiment of the vacuum pump device.

Fig. 11 is an exploded perspective view showing the side cover and a plurality of heat insulating members shown in Fig. 10.

Fig. 12 is a cross-sectional view taken along line G-G in Fig. 10.

Fig. 13 is a diagram showing an embodiment in which a plurality of side heaters are arranged in a side cover.

Fig. 14 is a cross-sectional view showing another embodiment of the vacuum pump device.

Fig. 15 is a cross-sectional view showing an embodiment of a vacuum pump device equipped with a multi-stage pump rotor.

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

Fig. 1 is a cross-sectional view showing an embodiment of the 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 vaporized oil in the dry vacuum pump device does not flow to the upstream side, so the dry vacuum pump device can be suitably used in a semiconductor device manufacturing device that requires a high degree of cleanliness.

As shown in FIG. 1, the vacuum pump device includes: a pump housing 2 having a rotor chamber 1 inside, a pump rotor 5 arranged in the rotor chamber 1, a rotating shaft 7 to which the pump rotor 5 is fixed, and an electric motor connected to the rotating shaft 7 8. The pump rotor 5 and the rotating shaft 7 may be an integral structure. In FIG. 1, only one pump rotor 5, one rotating shaft 7 and one electric motor 8 are depicted, but a pair of pump rotors 5 are arranged in the rotor chamber 1 and fixed to the pair of rotating shafts 7 respectively. The pair of motors 8 are respectively connected to the pair of rotation shafts 7.

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

The vacuum pump device further includes side covers 10A and 10B located outside the pump housing 2 in the axial direction of the rotating shaft 7. The side covers 10A and 10B are arranged on both sides of the pump casing 2 and connected with the pump casing 2. In the present embodiment, the side covers 10A and 10B are fixed to the end surface of the pump housing 2 by screws (not shown). In one embodiment, the side covers 10A and 10B can also be integrated with the pump housing 2.

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

The vacuum pump device further includes a bearing housing 12 as a housing structure, a motor housing 14 and a gear housing 16 located outside the side covers 10A and 10B in the axial direction of the rotating shaft 7. The side cover 10A is located between the pump housing 2 and the gear housing 16, and the side cover 10B is located between the pump housing 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 arranged in the bearing housing 12 and a bearing 18 arranged in the gear housing 16. The motor case 14 accommodates the motor rotor 8A and the motor stator 8B of the electric motor 8 inside. The bearing housing 12, the motor housing 14, and the gear housing 16 are examples of housing structures, and the housing structures are not limited to this embodiment.

Two electric motors 8 (only one electric motor 8 is shown in FIG. 1) are synchronously rotated in opposite directions by a motor driver not shown, and the pair of rotating shafts 7 and the pair of pump rotors 5 can be synchronously rotated in opposite directions. . When the pump rotor 5 is rotated by the electric motor 8, the gas is sucked into the pump casing 2 from the suction port 2a. The gas is transferred from the suction port 2a to the exhaust port 2b by the rotating pump rotor 5.

A pair of gears 20 meshing with each other is arranged inside the gear housing 16. In addition, only one gear 20 is depicted in FIG. 1. As described above, the pair of pump rotors 5 are synchronously rotated by the two motors 8, and therefore, the role of the gear 20 is to prevent the synchronous rotation of the pump rotor 5 from desynchronization due to sudden external factors.

A cooling pipe 21 is embedded in the gear housing 16. Similarly, a cooling pipe 22 is buried 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 in the cooling pipe 21 cools the gear housing 16, and thereby the gear 20 and the bearing 18 arranged in the gear housing 16 can be cooled. The coolant flowing in the cooling pipe 22 cools the motor housing 14 and the bearing housing 12, thereby being able to cool the electric motor 8 arranged in the motor housing 14 and the bearing 17 arranged in the bearing housing 12.

The vacuum pump device includes side heaters 55A and 55B arranged in side covers 10A and 10B, respectively. The side heaters 55A and 55B are arranged adjacent to the rotor chamber 1. The side cover 10A is provided with: forming a rotor chamber The inner side cover 31A of the end surface of 1 and the outer side cover 32A located outside the inner side cover 31A in the axial direction of the rotating shaft 7. The side heater 55A is arranged between the inner side cover 31A and the outer side cover 32A.

Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 1. As shown in FIG. 2, the outer surface of the inner side cover 31A has a groove 56 that surrounds the through hole 27 into which the rotating shaft 7 is inserted, and the side heater 55A is provided in the groove 56. The side heater 55A is an annular heater arranged to surround the rotating shaft 7 penetrating through the through hole 27. The type of the side heater 55A is not particularly limited, but a sheath heater, which is a type of electric heater, can be used for the side heater 55A.

The side cover 10A is located closer to the gear housing 16 provided with the cooling pipe 21 than the pump housing 2, so the temperature of the side cover 10A is likely to be lowered compared to the pump housing 2. According to the embodiment shown in FIGS. 1 and 2, a side heater 55A is provided between the pump housing 2 and the gear housing (housing structure) 16. The side heater 55A can heat the side cover 10A itself, and therefore can make the inside of the rotor chamber 1 whose end surface is formed by the side cover 10A become high in temperature. In particular, the gear housing 16 can be cooled by the coolant flowing in the cooling pipe 21, and the side heater 55A can maintain the inside of the rotor chamber 1 at a high temperature.

The process gas processed by the vacuum pump device of this embodiment sometimes contains by-products that solidify with a decrease in temperature. During the operation of the vacuum pump device, the process gas is compressed while being transferred from the suction port 2a to the exhaust port 2b by the pump rotor 5. Therefore, the interior of the rotor chamber 1 becomes high temperature due to the heat of compression of the process gas. Furthermore, according to the present embodiment, the side cover 10A is heated by the side heater 55A, so that the inside of the rotor chamber 1 can be maintained at a high temperature. Therefore, solidification of by-products can be reliably prevented.

The specific structure for arranging the side heater 55A in the side cover 10A is not limited to the embodiment shown in FIGS. 1 and 2. For example, it can also be formed by casting with a supply side heater 55A The side cover 10A is provided with a hole, and a side heater 55A is inserted into the hole. In this case, in the side cover 10A, the inner side cover 31A and the outer side cover 32A may not be separated.

In one embodiment, as shown in FIG. 3, a plurality of side heaters 55A may be arranged in the side cover 10A. In the embodiment shown in FIG. 3, two side heaters 55A extending side by side are arranged in the side cover 10A. Three or more side heaters 55A may be arranged.

Fig. 4(a) is a diagram showing another embodiment in which the side heater 55A is arranged in the side cover 10A, and Fig. 4(b) is a cross-sectional view taken along the line B-B of Fig. 4(a). As shown in Figs. 4(a) and 4(b), the side heater 55A may have a rod shape. Grooves 56 are formed on the side surface of the inner side cover 31A, and the side heaters 55A are arranged in these grooves 56. The through hole 27 into which the rotating shaft 7 is inserted is located between these side heaters 55A. Therefore, the side heater 55A is configured to surround the rotating shaft 7 extending in the through hole 27. In this embodiment, two grooves 56 are formed above and below the through hole 27 in parallel with each other, and two side heaters 55A are respectively arranged in these grooves 56. The side heaters 55A are also located above and below the through hole 27 and are parallel to each other. The embodiments shown in Figs. 4(a) and 4(b) have the advantages of easy formation of the groove 56 and reduced manufacturing cost.

Fig. 5(a) is a diagram showing another embodiment in which the side heater 55A is arranged in the side cover 10A, and Fig. 5(b) is a cross-sectional view taken along the line C-C in Fig. 5(a). As shown in FIG. 5(a) and FIG. 5(b), the rod-shaped side heater 55A may be arranged so as to surround the through hole 27 into which the rotating shaft 7 is inserted. In this embodiment, two grooves 56 are formed above and below the through hole 27 in parallel to each other, and further two grooves 56 are formed on both sides of the through hole 27 in parallel to each other. The four grooves 56 are formed on the side surface of the inner side cover 31A. The four side heaters 55A are respectively arranged in the four grooves 56. These side heaters 55A also surround the through hole 27 (and the rotating shaft 7). The side heater 55A arranged in this way can uniformly heat the rotor chamber 1. Five or more side heaters 55A may be provided.

Fig. 6(a) is a diagram showing another embodiment in which the side heater 55A is arranged in the side cover 10A, and Fig. 6(b) is a cross-sectional view taken along the line D-D of Fig. 6(a). As shown in FIGS. 6(a) and 6(b), the side heater 55A may have a rod shape. Holes 58 are formed in the inner side cover 31A, and the side heater 55A is arranged in these holes 58. The through hole 27 into which the rotating shaft 7 is inserted is located between these side heaters 55A. Therefore, the side heater 55A is arranged to surround the rotating shaft 7. In this embodiment, two holes 58 are formed parallel to each other above and below the through hole 27, and two side heaters 55A are respectively arranged in these holes 58. These side heaters 55A are also located above and below the through hole 27 and are parallel to each other. The embodiment shown in Figs. 6(a) and 6(b) has the advantages of easy formation of the hole 58 and reduced manufacturing cost.

Fig. 7(a) is a diagram showing another embodiment in which the side heater 55A is arranged in the side cover 10A, and Fig. 7(b) is a cross-sectional view taken along the line E-E of Fig. 7(a). As shown in FIG. 7(a) and FIG. 7(b), the rod-shaped side heater 55A may be arranged so as to surround the through hole 27 into which the rotating shaft 7 is inserted. Holes 58 are formed in the inner side cover 31A, and the side heater 55A is arranged in these holes 58. In this embodiment, two holes 58 are formed above and below the through hole 27 in parallel with each other, and further two holes 58 are formed on both sides of the through hole 27 in parallel with each other. The four side heaters 55A are arranged in the four holes 58 respectively. These side heaters 55A also surround the through hole 27 (and the rotating shaft 7). The side heater 55A arranged in this way can uniformly heat the rotor chamber 1. Five or more side heaters 55A may be provided.

Fig. 8(a) is a diagram showing another embodiment in which the side heater 55A is arranged in the side cover 10A, and Fig. 8(b) is a cross-sectional view taken along the line F-F of Fig. 8(a). As shown in FIGS. 8(a) and 8(b), the side heater 55A may be a sheet-shaped heater. The side heater 55A is attached to the side surface of the inner side cover 31A. In this embodiment, the side heater 55A has a ring shape surrounding the through hole 27 into which the rotating shaft 7 is inserted, but the shape of the side heater 55A is not limited to this embodiment. For example, you can also refer to Figure 4 to Figure 7 and As explained, the side heater 55A extends linearly so as to surround the through hole 27 through which the rotating shaft 7 passes.

The side heaters 55A of the embodiment described with reference to FIGS. 2 to 8 are all adjacent to the rotor chamber 1. The configuration of the side heater 55A described with reference to FIGS. 4 to 8 is an example, and does not mean that the present invention is limited to these embodiments.

As shown in FIG. 1, the side heater 55B is also arrange|positioned 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 32B located outside the inner side cover 31B in the axial direction of the rotating shaft 7. The outer surface of the inner side cover 31B has a groove (not shown), and the side heater 55B is provided in the groove. The side heater 55B is an annular heater or a rod-shaped heater arranged so as to surround the rotating shaft 7. The description of the side heater 55A and the side cover 10A with reference to FIGS. 1 to 8 can also be applied to the side heater 55B and the side cover 10B, so other descriptions of the side heater 55B and the side cover 10B are omitted.

Fig. 9 is a cross-sectional view showing another embodiment of the vacuum pump device. The structure of this embodiment, which is not specifically described, is the same as the embodiment described with reference to FIGS. 1 to 8, so the repeated description is omitted.

A heat insulating structure 25A as a heat insulating body is interposed between the side cover 10A and the gear housing (housing structure) 16. 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. The heat insulating structure 25A is located between the pump housing 2 and the gear housing 16 and has a function of reducing heat conduction from the pump housing 2 to the gear housing 16 through the side cover 10A.

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, 10B forming the rotor chamber 1 are made of cast iron. Bearing shell 12. Motor The housing 14 and the gear housing 16 are made of aluminum. The heat insulating structure 25A is made of 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 type of fluororesin. Polytetrafluoroethylene (PTFE) has lower thermal conductivity than cast iron and has the property of being able to withstand high temperatures. However, as long as the material has a lower thermal conductivity than the material of the side cover 10A, the material of the heat insulating structure 25A may be metal such as stainless steel, titanium, spheroidal graphite-based austenitic cast iron (Ni-resist).

Other housing structures such as a bearing housing may be arranged between the side cover 10A and the gear housing 16. In such a case, the heat insulating structure 25A is sandwiched between the side cover 10A and the outer shell structure.

The heat insulating structure 25A has a ring shape and is arranged to surround the outer peripheral surface of the rotating shaft 7. 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 insulation structure 25A has a continuous ring shape, and the heat insulation structure 25A also functions as a seal that seals the gap between the side cover 10A and the gear housing 16.

Similarly, the heat insulating structure 25B is sandwiched between the side cover 10B and the bearing shell (outer shell structure) 12. That is, the side cover 10B and the bearing shell 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 shell 12. This heat insulating structure 25B is located between the pump housing 2 and the bearing housing 12, and has a function of reducing heat conduction from the pump housing 2 to the bearing housing 12 through the side cover 10B.

The heat insulation structure 25B has a continuous annular shape, and the heat insulation structure 25B also functions as a seal that seals the gap between the side cover 10B and the bearing shell 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 shell 12. The heat insulation structure 25B has a thermal conductivity lower than that of 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. The structure of the heat-insulating structure 25B is the same as that of the heat-insulating structure 25A, so the repeated description is omitted.

Another shell structure may be arranged between the side cover 10B and the bearing shell 12. In such a case, the heat insulating structure 25B is sandwiched between the side cover 10B and the outer shell structure. In addition, there are cases where the bearing housing 12 is not provided between the side cover 10B and the motor housing 14. In such a case, the heat insulating structure 25B is sandwiched between the side cover 10B and the motor case 14.

Fig. 10 is a cross-sectional view showing another embodiment of the vacuum pump device. The structure of this embodiment, which is not specifically described, is the same as the embodiment described with reference to FIGS. 1 to 8, so the repeated description 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 heat insulating structures 25A and 25B are not provided.

A 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 in contact with both the inner side cover 31A and the outer side cover 32A. The plurality of heat insulating members 41A, 42A as the heat insulator are located between the pump housing 2 and the gear housing 16, and the plurality of heat insulating members 41A, 42A have a thermal conductivity lower than that of the side cover 10A. Therefore, the plural heat insulating members 41A and 42A have a function of reducing heat conduction from the pump housing 2 to the gear housing 16 through the side cover 10A.

Fig. 11 is an exploded perspective view showing the side cover 10A and a plurality of heat insulating members 41A and 42A shown in Fig. 10. The plural heat insulating members 41A and 42A include a heat insulating plate 41A having two through holes 45 through which the rotating shaft 7 penetrates, and a plurality of heat insulating pads 42A arranged around the heat insulating plate 41A. A recess 47 is formed on the outer surface of the inner side cover 31A, and the heat insulation board 41A is arranged in the recess 47. In one embodiment, a recess 47 may be formed on the inner surface of the outer side cover 32A, and the heat insulation board 41A is disposed in the recess 47 of the outer side cover 32A. The heat insulation board 41A of this embodiment is a single structure, but it may be separated into a plurality of structures. Seals (not shown) such as O-rings are arranged between the heat shield 41A and the inner side cover 31A, and between the heat shield 41A and the outer side cover 32A.

The heat insulation board 41A and the heat insulation pad 42A have lower thermal conductivity than the side cover 10A. Therefore, the heat insulation plate 41A and the heat insulation gasket 42A can reduce heat conduction from the pump housing 2 to the gear housing 16 through the side cover 10A, and maintain the rotor chamber 1 at a high temperature. In particular, the gear housing 16 can be cooled by the cooling liquid flowing through the cooling pipe 21 (refer to FIG. 10 ), and the heat insulation plate 41A and the heat insulation gasket 42A can maintain the inside of the rotor chamber 1 at a high temperature.

The heat insulation board 41A and the heat insulation pad 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, 10B constituting the rotor chamber 1 are made of cast iron. The heat insulation plate 41A and the heat insulation gasket 42A are made of metals such as stainless steel, titanium, or spheroidal graphite-based austenitic cast iron (Ni-resist), which have lower thermal conductivity than the material of the side cover 10A. In this embodiment, the heat insulation board 41A and the heat insulation pad 42A are made of stainless steel. Stainless steel has a lower thermal conductivity than cast iron. In addition, stainless steel has high mechanical rigidity and can ensure high dimensional accuracy during assembly of the vacuum pump device. However, as long as the thermal conductivity is lower than the material of the side cover 10A and the mechanical rigidity is higher, the material of the heat insulation board 41A and/or the heat insulation pad 42A may be other materials such as resin.

The total cross-sectional area of the heat insulation board 41A and the heat insulation pad 42A is smaller than the cross-sectional area of the side cover 10A. Therefore, the heat-insulating plate 41A and the heat-insulating gasket 42A, which have a small thermal conductivity and a small cross-sectional area, contribute to reducing heat conduction from the pump housing 2 to the gear housing 16.

As shown in Fig. 10, in the other side cover 10B, a plurality of heat insulating members 41B and 42B as heat insulators, that is, a heat insulating plate 41B, and a plurality of heat insulating pads 42B are similarly provided. The side cover 10B includes an inner side cover 31B forming an end surface of the rotor chamber 1 and an outer side cover 32B located outside the inner side cover 31B in the axial direction of the rotating shaft 7.

The structure and arrangement of the side cover 10B, the heat insulation board 41B, and the plurality of heat insulation pads 42B are substantially the same as the side cover 10A, the heat insulation board 41A, and the plurality of heat insulation pads 42A. The description of the side cover 10A, the heat insulation board 41A, and the plurality of heat insulation pads 42A with reference to FIGS. 10 and 11 can also be applied to the side cover 10B, the heat insulation board 41B, and the plurality of heat insulation pads 42B, so their descriptions are omitted Other detailed instructions.

The heat insulation plate 41B and the heat insulation gasket 42B formed in the side cover 10B are located between the pump housing 2 and the bearing housing 12. The heat insulation board 41B and the heat insulation pad 42B have lower thermal conductivity than the side cover 10B. Therefore, the heat insulation plate 41B and the heat insulation pad 42B have a function of reducing heat conduction from the pump housing 2 to the bearing housing 12 through the side cover 10B. In particular, the motor housing 14 and the bearing housing 12 can be cooled by the coolant flowing in the cooling pipe 22, and the heat insulation plate 41B and the heat insulation gasket 42B can maintain the inside of the rotor chamber 1 at a high temperature.

The total cross-sectional area of the heat insulation board 41B and the heat insulation pad 42B is smaller than the cross-sectional area of the side cover 10B. Therefore, the heat-insulating plate 41B and the heat-insulating gasket 42B, which have a small thermal conductivity and a small cross-sectional area, contribute to reducing heat conduction from the pump housing 2 to the bearing housing 12.

Fig. 12 is a cross-sectional view taken along line G-G in Fig. 10. As shown in FIG. 12, 55 A of side heaters are arrange|positioned so as to surround 41 A of heat insulation boards. Although not shown, the side heater 55B is similarly arranged to surround the heat shield 41B. As shown in FIG. 13, a plurality of side heaters 55A may be provided in the side cover 10A. Similarly, a plurality of side heaters 55B may be provided in the side cover 10B. In addition, the structure and arrangement of the side heater 55A and the side cover 10A described with reference to FIGS. 4 to 8 can also be applied to the side heater 55A and the side cover 10A and/or the side heating of the embodiment of FIGS. 10 and 11器55B and side cover 10B. In this case as well, the side heater 55A is arranged to surround the heat insulating plate 41A, and the side heater 55B is arranged to surround the heat insulating plate 41B.

Fig. 14 is a cross-sectional view showing another embodiment of the vacuum pump device. The structure of the present embodiment that is not specifically described is the same as the embodiment described with reference to FIGS. 1 to 13, so the repeated description is omitted. In this embodiment, as shown in FIG. 14, the vacuum pump device includes both heat-insulating structures 25A, 25B and heat-insulating members 41A, 42A, 41B, and 42B as heat insulators. According to this embodiment, the combination of the double insulators 25A, 25B, 41A, 42A, 41B, 42B and the side heaters 55A, 55B can maintain the inside of the rotor chamber 1 at a high temperature. In addition, it is possible to reduce the electric power required for the operation of the side heaters 55A and 55B.

In each embodiment described above, the side heaters 55A and 55B are arranged on both sides of the rotor chamber 1, but the present invention is not limited to such an arrangement. In one embodiment, the side heater may be arranged 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 side heater 55A may be omitted. Similarly, the above-mentioned heat insulators are arranged on both sides of the rotor chamber 1, but in one embodiment, the heat insulators may be arranged on only one side of the rotor chamber 1.

Fig. 15 is a cross-sectional view showing an embodiment of a vacuum pump device equipped with a multi-stage pump rotor. The structure of this embodiment that is not specifically described is the same as that of the embodiment shown in FIG. 14, so the repeated description is omitted. The vacuum pump device shown in FIG. 15 includes a multi-stage pump rotor 5 having a plurality of rotors 5a to 5e. The suction port 2 a is located at the end of the pump housing 2 on the gear side, and the exhaust port 2 b is located at the end of the pump housing 2 on the motor side. Along with the rotation of the multi-stage pump rotor 5, the gas is transferred from the suction port 2a to the exhaust port 2b while being compressed. The compression heat 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, it sometimes contains by-products with a relatively low sublimation temperature. Such by-products are easy to solidify on the suction side of the rotor chamber 1, on the other hand, they are not easy to solidify on the exhaust side of the rotor chamber 1. Therefore, in this case, as shown in Fig. 15, the vacuum pump device is only in the gear A side heater 55A and/or a heat insulating structure 25A and/or heat insulating members 41A and 42A are provided between the housing 16 and the pump housing 2.

The above-mentioned embodiments are described for the purpose of being able to implement the present invention by a person with ordinary knowledge in the technical field to which the present invention belongs. Various modifications of the above-mentioned embodiments are natural to those skilled in the art, and the technical idea of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is interpreted as the broadest scope of the technical idea defined by the patent application scope of the present invention.

1: Rotor chamber

2: pump housing

2a: suction port

2b: Exhaust port

5: Pump rotor

7: Rotation axis

8: Electric motor

8A: Motor rotor

8B: Motor stator

10A, 10B: side cover

12: Bearing shell

14: Motor housing

16: gear housing

17: Bearing

18: Bearing

20: Gear

21, 22: Cooling pipe

31A, 31B: inner side cover

32A, 32B: Outer side cover

55A, 55B: side heater

Claims (3)

A vacuum pump device with: The pump casing has a rotor chamber inside; The pump rotor is arranged in the aforementioned rotor chamber; The rotating shaft is fixed with the aforementioned pump rotor; The electric motor is connected with the aforementioned rotating shaft; The side cover forms the end face of the aforementioned rotor chamber; and The side heater is arranged in the aforementioned side cover. The vacuum pump device according to claim 1, wherein: The side heater is arranged to surround the rotation shaft. The vacuum pump device according to claim 1 or 2, wherein: The aforementioned side cover includes: an inner side cover forming an end surface of the rotor chamber, and an outer side cover located outside the inner side cover in the axial direction of the rotating shaft; The side heater is arranged between the inner side cover and the outer side cover.

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