Vacuum pump device

Abstract

The present invention provides a vacuum pump device, which can prevent the temperature of a pump housing from decreasing due to heat conduction and can maintain the interior of a rotor chamber at a relatively high temperature. The vacuum pump device comprises: a pump housing (2) having a rotor chamber (1) therein; a pump rotor (5) disposed 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); a housing structure (16) located outside the side cover (10A) in the axial direction of the rotating shaft (7); and a heat insulator (25A) located between the pump housing (2) and the housing structure (16).

Description

Technical Field

[0001] The present invention relates to a vacuum pump device, and in particular to a vacuum pump device suitable for exhausting process gases used in the manufacture of semiconductor devices, liquid crystals, LEDs, solar cells, and the like. Background Art

[0002] In the manufacturing process of semiconductor devices, liquid crystal panels, LEDs, solar cells, etc., process gases are introduced into the process chamber to perform various processes such as etching and CVD. The process gases introduced into the process chamber are exhausted by a vacuum pump device. Generally, the vacuum pump devices used in these manufacturing processes that require a higher degree of 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 transfers gas by rotating a pair of pump rotors arranged in a rotor chamber in opposite directions.

[0003] The process gas sometimes contains by-products with a high 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 pump rotor and the inner surface of the pump housing. 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, causing the vacuum pump device to stop operating. Therefore, in order to prevent the solidification of the by-products, a heater is installed on the outer surface of the pump housing to heat the rotor chamber.

[0004] On the other hand, it is necessary to cool the motor that drives the pump rotor and the gears fixed to the rotating shaft of the pump rotor. Therefore, the above-mentioned vacuum pump device is usually equipped with a cooling system for cooling the motor and the gears. The cooling system is configured, for example, to cool the motor and the gears by circulating the coolant through a cooling pipe provided in a motor housing that accommodates the motor and circulating the coolant through a cooling pipe provided in a gear housing that accommodates the gears. With such a cooling system, it is possible to prevent the motor and the gears from overheating, thereby achieving stable operation of the vacuum pump device.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-35290

[0008] Patent Document 2: Japanese Patent Application Publication No. 2012-251470

[0009] Technical problem to be solved by the invention

[0010] However, the heat of the pump housing heated by the heater is easily transferred to the motor housing and gear housing with lower temperatures. As a result of such heat conduction, the temperature of the rotor chamber in the pump housing sometimes decreases. In particular, since the end face of the rotor chamber is located close to the motor housing or gear housing with lower temperatures, the temperature of the end face of the rotor chamber is easily reduced. 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, but such a heater requires more electricity and cannot achieve energy-saving operation of the vacuum pump device. Summary of the invention

[0011] Here, the present invention provides a vacuum pump device capable of preventing a decrease in the temperature of a pump housing due to heat conduction and maintaining the interior of a rotor chamber at a high temperature.

[0012] Technical means for solving technical problems

[0013] In one embodiment, a vacuum pump device is provided, which includes: a pump housing having a rotor chamber inside; a pump rotor, which is arranged in the rotor chamber; a rotating shaft, to which the pump rotor is fixed; a motor, which is connected to the rotating shaft; a side cover, which forms an end surface of the rotor chamber; a shell structure, which is located outside the side cover in the axial direction of the rotating shaft; and an insulator, which is located between the pump housing and the shell structure.

[0014] In one embodiment, the heat insulator includes a heat insulating structure interposed between the side cover and the outer shell structure.

[0015] In one embodiment, the side cover has a hollow structure having a space therein, and the heat insulator includes a gas layer existing in the space of the side cover.

[0016] In one embodiment, the heat insulator includes a heat insulating member disposed in the side cover.

[0017] In one embodiment, 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, and the heat insulating member is interposed between the inner side cover and the outer side cover.

[0018] In one embodiment, a cross-sectional area of ​​the heat insulating member is smaller than a cross-sectional area of ​​the side cover.

[0019] In one embodiment, a side heater is further provided in the side cover.

[0020] Effects of the Invention

[0021] The heat insulator disposed between the pump housing and the housing structure can reduce heat conduction from the pump housing to the housing structure, thereby maintaining the interior of the rotor chamber at a relatively high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a cross-sectional view showing one embodiment of the vacuum pump device.

[0023] Figure 2 It is an exploded perspective view showing the side cover, the heat insulator and the gear case.

[0024] Figure 3 It is a cross-sectional view showing another embodiment of the vacuum pump device.

[0025] Figure 4 yes Figure 3 An enlarged cross-sectional view of the side shield is shown.

[0026] Figure 5 It is a cross-sectional view showing another embodiment of the vacuum pump device.

[0027] Figure 6 Yes means Figure 5 An exploded perspective view of the side shield and multiple insulation components are shown.

[0028] Figure 7 It is a cross-sectional view showing another embodiment of the vacuum pump device.

[0029] Figure 8 It is a cross-sectional view showing another embodiment of the vacuum pump device.

[0030] Fig. 9 This is a cross-sectional view showing an embodiment in which a heater is mounted on the outer surface of a pump housing.

[0031] Fig.10 This is a cross-sectional view showing an embodiment in which the side heater is buried in the side cover.

[0032] Fig.11 yes Fig.10 AA line section view.

[0033] Fig.12 This is a diagram showing an embodiment in which a plurality of side heaters are arranged in a side cover.

[0034] Fig.13 Yes means have Figure 8 The two insulators shown and Fig.10 A cross-sectional view of one embodiment of a vacuum pump arrangement for a side heater is shown.

[0035] Fig.14 yes Fig.13 The BB line cross-sectional view is shown.

[0036] Fig.15 This is a diagram showing an embodiment in which a plurality of side heaters are arranged in a side cover.

[0037] Fig.16 This 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 the outer surface of a pump case.

[0038] Fig.17 This is a cross-sectional view showing one embodiment of a vacuum pump device including a multi-stage pump rotor.

[0039] Explanation of symbols

[0040] 1 Rotor chamber

[0041] 2 Pump casing

[0042] 2a Inlet

[0043] 2b Exhaust port

[0044] 5 Pump rotor

[0045] 7 Rotation axis

[0046] 8 Electric Motor

[0047] 8A Motor rotor

[0048] 8B Motor stator

[0049] 10A, 10B side covers

[0050] 12 Bearing shell

[0051] 14 Motor housing

[0052] 16 Gear housing

[0053] 17 Bearings

[0054] 18 Bearings

[0055] 20 Gear

[0056] 21 Cooling pipe

[0057] 22 Cooling pipe

[0058] 25A, 25B Insulation structure

[0059] 27 Through Holes

[0060] 29A, 29B Gas layer

[0061] 31A, 31B Inner side covers

[0062] 32A, 32B Outer side covers

[0063] 33 Depression

[0064] 34 Space

[0065] 35 Seals

[0066] 41A, 41B Insulation components (insulation panels)

[0067] 42A, 42B Insulation components (insulation pads)

[0068] 45 Through Hole

[0069] 47 Depression

[0070] 50 Heater

[0071] 55A, 55B side heater

[0072] 56 slots DETAILED DESCRIPTION

[0073] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0074] Figure 1 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, Figure 1 The vacuum pump device shown is a so-called dry vacuum pump device that does not use oil in the gas flow path. In the dry vacuum pump device, vaporized oil does not flow to the upstream side, so the dry vacuum pump device can be suitably used in semiconductor device manufacturing equipment that requires high cleanliness.

[0075] like Figure 1 As shown, the vacuum pump device includes: a pump housing 2 having a rotor chamber 1 therein, a pump rotor 5 disposed in the rotor chamber 1, a rotating shaft 7 to which the pump rotor 5 is fixed, and a motor 8 connected to the rotating shaft 7. The pump rotor 5 and the rotating shaft 7 may also be an integral structure. Figure 1 In FIG. 1 , only one pump rotor 5 , one rotating shaft 7 , and one motor 8 are depicted, but a pair of pump rotors 5 are disposed in the rotor chamber 1 and are respectively fixed to a pair of rotating shafts 7 . A pair of motors 8 are respectively connected to the pair of rotating shafts 7 .

[0076] 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. Furthermore, 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.

[0077] The vacuum pump device also 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 housing 2 and connected to the pump housing 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 may also be integrated with the pump housing 2.

[0078] The rotor chamber 1 is formed by the inner surface of the pump housing 2 and the inner surfaces of the side covers 10A and 10B. The pump housing 2 has an air intake port 2a and an exhaust port 2b. The air intake port 2a is connected to a chamber (not shown) filled with gas to be transferred. In one example, the air intake port 2a is connected to a process chamber of a semiconductor device manufacturing device, and the vacuum pump device is used to exhaust the process gas introduced into the process chamber.

[0079] The vacuum pump device also includes a bearing housing 12, a motor housing 14, and a gear housing 16 as a housing structure located outside the side housings 10A and 10B in the axial direction of the rotating shaft 7. The side housing 10A is located between the pump housing 2 and the gear housing 16, and the side housing 10B is located between the pump housing 2 and the bearing housing 12. The bearing housing 12 is located between the side housing 10B and the motor housing 14.

[0080] 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 accommodates 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 the present embodiment.

[0081] Two motors 8 (in Figure 1 Only one motor 8 is shown in the figure) and the motor driver (not shown) rotates synchronously in opposite directions, which can make a pair of rotating shafts 7 and a pair of pump rotors 5 rotate synchronously in opposite directions. When the pump rotor 5 is rotated by the motor 8, the gas is sucked into the pump housing 2 from the air intake port 2a. The gas is transferred from the air intake port 2a to the exhaust port 2b through the rotating pump rotor 5.

[0082] A pair of gears 20 meshing with each other are disposed inside the gear housing 16. Figure 1 Only one gear 20 is shown in the figure. As described above, the pair of pump rotors 5 are rotated synchronously by the two motors 8, so the gear 20 serves to prevent the synchronous rotation of the pump rotors 5 from being lost due to a sudden external factor.

[0083] A cooling pipe 21 is buried in the gear housing 16. Similarly, a cooling pipe 22 is buried in the motor housing 14. The cooling pipe 21 extends along the entire circumferential wall of the gear housing 16, and the cooling pipe 22 extends along the entire circumferential wall of the motor housing 14. The cooling pipe 21 and the cooling pipe 22 are connected to a coolant supply source (not shown). Coolant is supplied from the coolant supply source to the cooling pipe 21 and the cooling pipe 22. The coolant flowing in the cooling pipe 21 cools the gear housing 16, thereby cooling the gear 20 and the bearing 18 arranged in the gear housing 16. The coolant flowing in the cooling pipe 22 cools the motor housing 14 and the bearing housing 12, thereby cooling the electric motor 8 arranged in the motor housing 14 and the bearing 17 arranged in the bearing housing 12.

[0084] A heat insulating structure 25A as a heat insulator is sandwiched 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.

[0085] The process gas processed by the vacuum pump device of this embodiment sometimes contains by-products that solidify as the temperature decreases. During the operation of the vacuum pump device, the process gas is compressed in the process of being transferred from the air intake port 2a to the air exhaust port 2b through the pump rotor 5. Therefore, the interior of the rotor chamber 1 becomes hot due to the compression heat of the process gas. The heat-insulating structure 25A can reduce the heat conduction from the pump housing 2 through the side cover 10A toward the gear housing 16, and can maintain the rotor chamber 1 at a high temperature. In particular, the gear housing 16 can be cooled by the coolant flowing in the cooling pipe 21, and the heat-insulating structure 25A can maintain the rotor chamber 1 at a high temperature.

[0086] 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 the present embodiment, the pump housing 2 and the side covers 10A, 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 type of fluororesin. Polytetrafluoroethylene (PTFE) has a lower thermal conductivity than cast iron and has the property of being able to withstand high temperatures. However, as long as it is a material having a lower thermal conductivity than the material of the side cover 10A, the material of the heat-insulating structure 25A may also be a metal such as stainless steel, titanium, or spheroidal graphite austenitic cast iron (Ni-resist).

[0087] Another housing structure such as a bearing housing may be disposed between the side cover 10A and the gear housing 16. In such a case, the heat insulating structure 25A is interposed between the side cover 10A and the housing structure.

[0088] Figure 2 1 is an exploded perspective view showing the side cover 10A, the heat insulating structure 25A and the gear housing 16. Figure 2 As shown, the heat insulating structure 25A is annular and is arranged to surround the rotating shaft 7 (see Figure 1 ) on the outer peripheral surface of the gear housing 16. The side cover 10A has a through hole 27 for the rotating shaft 7 to pass through. The through hole 27 is connected to the rotor chamber 1. The heat insulating structure 25A is arranged around these through holes 27. The inner side surface of the heat insulating structure 25A contacts the outer side surface of the side cover 10A, and the outer side surface of the heat insulating structure 25A contacts the inner end surface of the gear housing 16. The heat insulating structure 25A has a continuous annular shape, and the heat insulating structure 25A also functions as a seal that seals the gap between the side cover 10A and the gear housing 16.

[0089] Similarly, a heat insulating structure 25B is sandwiched between the side cover 10B and the bearing shell (housing 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. The heat insulating structure 25B is located between the pump shell 2 and the bearing shell 12, and has a function of reducing heat conduction from the pump shell 2 to the bearing shell 12 through the side cover 10B. In particular, the motor shell 14 and the bearing shell 12 can be cooled by the coolant flowing in the cooling pipe 22, and the heat insulating structure 25B can maintain the rotor chamber 1 at a high temperature.

[0090] The heat insulating structure 25B has a continuous annular shape, and the heat insulating 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 side surface of the heat insulating structure 25B contacts the outer side surface of the side cover 10B, and the outer side surface of the heat insulating structure 25B contacts the inner end surface of the bearing shell 12. The heat insulating structure 25B has a lower thermal conductivity than the side cover 10B. More specifically, the heat insulating structure 25B is composed of a material with 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 its repeated description is omitted.

[0091] 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, there is also a case where the bearing housing 12 is not disposed between the side cover 10B and the motor housing 14. In this case, the heat insulating structure 25B is sandwiched between the side cover 10B and the motor housing 14.

[0092] Figure 3 2 is a cross-sectional view showing another embodiment of the vacuum pump device. Figure 1 Since the embodiments described are the same, the repeated description thereof will be omitted. In this embodiment, a gas layer 29A as a heat insulator is provided in the side cover 10A. The heat insulating structures 25A and 25B are not provided.

[0093] The gas layer 29A is located between the pump housing 2 and the gear housing 16, and the gas layer 29A has a lower thermal conductivity than the side cover 10A. Therefore, the gas layer 29A has a function of reducing heat conduction from the pump housing 2 through the side cover 10A toward the gear housing 16. The side cover 10A has a hollow structure having a space inside. The heat insulator of this embodiment is the gas layer 29A present in the space of the side cover 10A.

[0094] Figure 4 yes Figure 3 1 is an enlarged cross-sectional view of the side cover 10A shown in FIG. The side cover 10A includes an inner side cover 31A that forms an end surface of the rotor chamber 1, and an outer side cover 32A that is located outside the inner side cover 31A in the axial direction of the rotating shaft 7. A recess 33 is formed on the outer surface of the inner side cover 31A. The recess 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.

[0095] When the outer surface of the inner side cover 31A and the inner surface of the outer side cover 32A are made to 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. The space 34 expands radially outward from the through hole 27 through which the rotating shaft 7 passes. The space 34 is connected to the through hole 27, and the through hole 27 is connected to the rotor chamber 1. An annular seal 35 such as an O-ring is arranged on the radial outer side of the recess 33. The recess 33 is surrounded by the seal 35. The seal 35 seals the gap between the outer surface of the inner side cover 31A and the inner surface of the outer side cover 32A.

[0096] The gas layer 29A is formed in the space 34. Generally, gas has a lower thermal conductivity than solid. In particular, since the space 34 is connected to the rotor chamber 1, the gas layer 29A is composed of a gas with a pressure lower than the atmospheric pressure during the operation of the vacuum pump device. The gas constituting the gas layer 29A is air, N2, 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.

[0097] The gas 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 conduction from the pump housing 2 to the gear housing (housing structure) 16. In particular, the gear housing 16 can be cooled by the coolant flowing in the cooling pipe 21, and the gas layer 29A can maintain the inside of the rotor chamber 1 at a high temperature. In addition, the gas layer 29A substantially reduces the cross-section of the side cover 10A, thereby helping to reduce the heat conduction from the pump housing 2 to the gear housing (housing structure) 16.

[0098] like Figure 3 As shown, a gas layer 29B as a heat insulator is also provided in the other side cover 10B. The side cover 10B has a hollow structure having a space inside. 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 of the side cover 10B is substantially the same as that of the side cover 10A. Figure 3 and Figure 4 The description of the side cover 10A is also applicable to the side cover 10B, and thus other detailed descriptions of the side cover 10B are omitted.

[0099] The gas layer 29B formed in the side cover 10B is located between the pump housing 2 and the bearing housing 12. The gas layer 29B has a lower thermal conductivity than the side cover 10B. Therefore, the gas layer 29B has a function of reducing the 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 gas layer 29B can maintain the rotor chamber 1 at a high temperature. In addition, the gas layer 29B substantially reduces the cross-section of the side cover 10B, thereby helping to reduce the heat conduction from the pump housing 2 to the bearing housing 12.

[0100] Figure 5 2 is a cross-sectional view showing another embodiment of the vacuum pump device. Figure 3 Since the embodiments described are the same, the repeated description thereof is omitted. In the present embodiment, a plurality of heat insulating members 41A and 42A are provided as heat insulators 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 32A located outside the inner side cover 31A in the axial direction of the rotating shaft 7.

[0101] The plurality of heat insulating components 41A, 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 components 41A, 42A are in contact with both the inner side cover 31A and the outer side cover 32A. The plurality of heat insulating components 41A, 42A as the heat insulator are located between the pump housing 2 and the gear housing 16, and the plurality of heat insulating components 41A, 42A have a lower thermal conductivity than the side cover 10A. Therefore, the plurality of heat insulating components 41A, 42A have a function of reducing heat conduction from the pump housing 2 through the side cover 10A toward the gear housing 16.

[0102] Figure 6 Yes means Figure 5 The side cover 10A and the exploded stereoscopic view of the plurality of heat insulating components 41A, 42A shown. The plurality of heat insulating components 41A, 42A include: a heat insulating plate 41A having two through holes 45 for the rotating shaft 7 to pass through, 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 insulating plate 41A is arranged in the recess 47. In one embodiment, a recess 47 may also be formed on the inner surface of the outer side cover 32A, and the heat insulating plate 41A may be arranged in the recess 47 of the outer side cover 32A. The heat insulating plate 41A of the present embodiment is a single structure, but may also be separated into a plurality of structures. Seals such as O-rings (not shown) are arranged 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.

[0103] The heat insulating plate 41A and the heat insulating pad 42A have a lower thermal conductivity than the side cover 10A. Therefore, the heat insulating plate 41A and the heat insulating pad 42A can reduce the 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, it can be used in the cooling pipe 21 (refer to Figure 5 ) cools the gear housing 16, and the heat insulation plate 41A and the heat insulation pad 42A can maintain the rotor chamber 1 at a high temperature.

[0104] The heat insulation plate 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 the present embodiment, the pump housing 2 and the side covers 10A and 10B constituting the rotor chamber 1 are made of cast iron. The heat insulation plate 41A and the heat insulation pad 42A are made of metals such as stainless steel, titanium, or spheroidal graphite austenitic cast iron (Ni-resist) having a lower thermal conductivity than the material of the side cover 10A. In the present embodiment, the heat insulation plate 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 a higher mechanical rigidity and can ensure a higher dimensional accuracy when assembling the vacuum pump device. However, as long as the heat conductivity is lower than that of the material of the side cover 10A and it has a higher mechanical rigidity, the material of the heat insulation plate 41A and / or the heat insulation pad 42A may also be other materials such as resin.

[0105] The total cross-sectional area of ​​the heat shield 41A and the heat insulating pad 42A is smaller than the cross-sectional area of ​​the side cover 10A. Therefore, the heat shield 41A and the heat insulating pad 42A having small thermal conductivity and cross-sectional area contribute to reducing heat conduction from the pump housing 2 to the gear housing 16.

[0106] like Figure 5 As shown in FIG. 1 , a plurality of heat insulating members 41B and 42B, namely, a heat insulating plate 41B and a plurality of heat insulating pads 42B, are similarly provided in the other side cover 10B as heat insulators. 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.

[0107] The structure and arrangement of the side cover 10B, the heat shield 41B, and the plurality of heat insulating pads 42B are substantially the same as those of the side cover 10A, the heat shield 41A, and the plurality of heat insulating pads 42A. Figure 5 and Figure 6 The description of the side cover 10A, the heat shield 41A, and the plurality of heat insulating pads 42A can also be applied to the side cover 10B, the heat shield 41B, and the plurality of heat insulating pads 42B, and therefore other detailed descriptions thereof are omitted.

[0108] The heat insulating plate 41B and the heat insulating pad 42B formed in the side cover 10B are located between the pump housing 2 and the bearing housing 12. The heat insulating plate 41B and the heat insulating pad 42B have a lower thermal conductivity than the side cover 10B. Therefore, the heat insulating plate 41B and the heat insulating 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 insulating plate 41B and the heat insulating pad 42B can maintain the rotor chamber 1 at a high temperature.

[0109] The total cross-sectional area of ​​the heat insulating plate 41B and the heat insulating gasket 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 having small thermal conductivity and cross-sectional area contribute to reducing heat conduction from the pump housing 2 to the bearing housing 12.

[0110] Figure 7 1 is a cross-sectional view showing another embodiment of the vacuum pump device. Figures 1 to 4 The embodiments described are the same, so the repeated description is omitted. Figure 7 As shown, the vacuum pump device includes both the heat insulating structures 25A and 25B and the gas layers 29A and 29B. According to the present 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 gas layers 29A and 29B.

[0111] Figure 8 1 is a cross-sectional view showing another embodiment of the vacuum pump device. Figure 1 , Figure 2 , Figure 5 and Figure 6 The embodiments described are the same, so the repeated description is omitted. Figure 8 As shown, the vacuum pump device includes both the heat insulating structures 25A, 25B and the heat insulating members 41A, 42A, 41B, 42B. According to this embodiment, the heat insulating structures 25A, 25B and the heat insulating members 41A, 42A, 41B, 42B form a double heat insulating body, and the rotor chamber 1 can be maintained at a high temperature.

[0112] In order to maintain the rotor chamber 1 at a higher temperature, Fig. 9 As shown, a heater 50 is provided on the outer surface of the pump housing 2. The type of the heater 50 is not particularly limited, and for example, an electric heater is installed on the outer surface of the pump housing 2. The pump housing 2 is heated by the heater 50, and the rotor chamber 1 is maintained at a relatively high temperature, so that the solidification of the by-products contained in the process gas can be reliably prevented. In addition, the heat insulating structures 25A and 25B have the function of maintaining the heat in the rotor chamber 1, so that the power required for the operation of the heater 50 can be reduced.

[0113] Fig. 9 The embodiment shown is in Figure 1 The vacuum pump device of the embodiment shown has a heater 50 mounted on the outer surface of the pump housing 2. Fig. 9 The heater 50 shown can also be used in Figure 3 , Figure 5 , Figure 7 and Figure 8 Various embodiments shown.

[0114] Fig.10 1 is a cross-sectional view showing an embodiment in which the side heaters 55A and 55B are buried in the side covers 10A and 10B. Fig.11 yes Fig.10 The structure of this embodiment not specifically described is similar to that of the reference Figure 1 and Figure 2 The described implementation methods are the same, so repeated descriptions are omitted.

[0115] The side cover 10A includes an inner side cover 31A forming an end surface of the rotor chamber 1 and an 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 disposed between the inner side cover 31A and the outer side cover 32A.

[0116] like Fig.11 As shown, the outer surface of the inner side cover 31A has a groove 56 surrounding the through hole 27 for inserting the rotating shaft 7, and the side heater 55A is provided in the groove 56. The side heater 55A is arranged to surround the through hole 27. The side heater 55A is an annular heater arranged in a manner to surround the rotating shaft 7 passing through the through hole 27. The type of the side heater 55A is not particularly limited, and a sheath heater, which is a kind of electric heater, can be used for the side heater 55A.

[0117] 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 easier to be lowered than that of the pump housing 2. Fig.10 and Fig.11 In the illustrated embodiment, 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 thus can heat the inside of the rotor chamber 1 whose end surface is formed by the side cover 10A.

[0118] The specific structure for arranging the side heater 55A in the side cover 10A is not limited to Fig.10 and Fig.11 For example, the side cover 10A having a hole for arranging the side heater 55A may be formed by casting, and the side heater 55A may be inserted into the hole. In this case, the inner side cover 31A and the outer side cover 32A in the side cover 10A may not be separated.

[0119] In one embodiment, if Fig.12 As shown, a plurality of side heaters 55A may be arranged in the side cover 10A. Fig.12 In the illustrated embodiment, two side heaters 55A extending in parallel are arranged in the side cover 10A. Three or more side heaters 55A may be arranged.

[0120] like Fig.10 As shown, the side heater 55B is also arranged in the side cover 10B. The side cover 10B includes: an inner side cover 31B forming the 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 set in the groove. The side heater 55B is an annular heater arranged in a manner to surround the rotating shaft 7. Figures 10 to 12 The description of the side heater 55A and the side cover 10A 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.

[0121] Figures 10 to 12 The side heaters 55A, 55B shown can also be applied to Figure 3 , Figure 5 , Figure 7 and Figure 8 Various embodiments shown.

[0122] Fig.13 Yes means have Figure 8 The heat insulating structures 25A, 25B and the heat insulating members 41A, 42A, 41B, 42B shown, and Fig.10 A cross-sectional view of one embodiment of a vacuum pump arrangement for side heaters 55A, 55B is shown. Fig.14 yes Fig.13 The BB line cross-sectional view is shown. Fig.14 As shown, the side heater 55A is arranged to surround the heat insulation board 41A. Although not shown, the side heater 55B is also arranged to surround the heat insulation board 41B. Fig.15 As shown, a plurality of side heaters 55A may be provided. Similarly, a plurality of side heaters 55B may be provided.

[0123] according to Figures 13 to 15 In the embodiment shown, the rotor chamber 1 can be kept at a high temperature by the combination of the double heat insulators 25A, 25B, 41A, 42A, 41B, 42B and the side heaters 55A, 55B. In addition, the power required for operating the side heaters 55A, 55B can be reduced.

[0124] like Fig.16 As shown, the side heaters 55A and 55B may be combined with the heater 50 mounted on the outer surface of the pump housing 2. The combination of the side heaters 55A and 55B and the heater 50 can be applied to the above-mentioned embodiments.

[0125] In each of the embodiments described above, a heat insulator is arranged 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 arranged only on one side of the rotor chamber 1. For example, in a case where the gear housing 16 is not provided with a cooling pipe 21, the heat insulating structure 25A and / or the heat insulating components 41A, 42A may be omitted. Similarly, the above-mentioned side heaters 55A, 55B are arranged on both sides of the rotor chamber 1, but in one embodiment, the side heater 55A or the side heater 55B may be arranged only on one side of the rotor chamber 1.

[0126] Fig.17 FIG. 1 is a cross-sectional view showing an embodiment of a vacuum pump device having a multi-stage pump rotor. Fig.13 The illustrated embodiments are the same, and thus repeated descriptions thereof are omitted. Fig.17 The vacuum pump device shown has a multi-stage pump rotor 5 having a plurality of rotors 5a to 5e. The air intake port 2a is located at the end of the pump housing 2 on the gear side, and the air exhaust port 2b is located at the end of the pump housing 2 on the motor side. As the multi-stage pump rotor 5 rotates, the gas is transferred from the air intake port 2a to the air exhaust port 2b while being compressed. The compression heat generated when the gas is compressed is highest near the air 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.

[0127] Depending on the type of process gas, byproducts with relatively low sublimation temperatures may be included. Such byproducts tend to solidify on the intake side of the rotor chamber 1, but do not easily solidify on the exhaust side of the rotor chamber 1. Therefore, in such a case, Fig.17 As shown, the vacuum pump device includes the heat insulating structure 25A and / or the heat insulating members 41A and 42A and / or the side heater 55A only between the gear housing 16 and the pump housing 2 .

[0128] The above-mentioned embodiments are recorded for the purpose of enabling a person with common knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above-mentioned embodiments are self-evident to those skilled in the art, and the technical concept 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 widest scope of the technical concept defined by the scope of protection claimed by the present invention.

Claims

1. A vacuum pump device, characterized in that: have: a pump housing having a rotor chamber therein; a pump rotor disposed in the rotor chamber; a rotating shaft to which the pump rotor is fixed; a 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 rotating shaft; as well as a heat insulator, the heat insulator being located between the pump casing and the housing structure, The heat insulator includes a heat insulating member disposed in the side cover, 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. The heat insulating member is sandwiched between the inner side cover and the outer side cover, The heat insulating component includes a heat insulating plate and a plurality of heat insulating pads, the heat insulating plate having a through hole for the rotating shaft to pass through, the plurality of heat insulating pads being arranged around the heat insulating plate, the plurality of heat insulating pads being arranged at intervals from each other and being separated from the heat insulating plate, A total cross-sectional area of ​​the heat insulation board and the plurality of heat insulation pads is smaller than a cross-sectional area of ​​the side cover.

2. The vacuum pump device according to claim 1, characterized in that: The heat insulator includes a heat insulating structure interposed between the side cover and the outer shell structure.

3. The vacuum pump device according to claim 1, characterized in that: The side cover has a hollow structure having a space inside. The heat insulator includes a gas layer existing in the space of the side cover.

4. The vacuum pump device according to claim 1, characterized in that: The heat insulating plate and the plurality of heat insulating pads are made of a material having a lower thermal conductivity than a material constituting the side cover.

5. The vacuum pump device according to any one of claims 1 to 4, characterized in that: A side heater is further provided which is arranged in the side cover.

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