KR20230092765A - Vacuum pump apparatus and method of operating the same - Google Patents

Abstract

A vacuum pump capable of reducing deposition of by-products caused by process gas in a pump chamber, preventing unintentional stoppage of a vacuum pump device, and ensuring restart of the vacuum pump device.
The vacuum pump device includes a pump casing 2 having a pump chamber 1 therein, a pump rotor 5E disposed in the pump chamber 1, a rotary shaft 7 to which the pump rotor 5E is fixed, and a rotary shaft ( The bearing 17 rotatably supporting the 7), the side cover 10A connected to the pump casing 2, the heater 35 provided in the side cover 10A, and the pump rotor 5E rotate. When present, a heater controller 40 for intermittently heating the heater 35 is provided, and the bearing 17 is connected to the side cover 10A.

Description

Vacuum pump device and its operating method {VACUUM PUMP APPARATUS AND METHOD OF OPERATING THE SAME}

The present invention relates to a vacuum pump device and its operating method, and in particular, a vacuum pump device suitable for exhausting process gases used in the manufacture of semiconductor devices, liquid crystal panels, LEDs, solar cells and the like, and its operating method It is about.

BACKGROUND OF THE INVENTION In processes for manufacturing semiconductor devices, liquid crystal panels, LEDs, solar cells, and the like, process gases are 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 a vacuum pump device. In general, vacuum pump devices used in these manufacturing processes requiring high cleanliness are so-called dry vacuum pump devices that do not use oil in the flow path of gas. As a typical 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 disposed in a pump chamber in opposite directions.

When the process gas introduced into the process chamber undergoes a reaction within the chamber and its temperature decreases or rises, solidified by-products may be formed. If a large amount of solidified by-products accumulates in the vacuum pump device, rotation of the pump rotor may be inhibited, causing sudden stop of the vacuum pump device. If the vacuum pump device unexpectedly stops, products such as semiconductor devices under manufacture will be damaged.

The above-mentioned by-products are also deposited in the pipe connecting the process chamber and the vacuum pump device or the pipe connecting the vacuum pump device and the downstream eliminator. For this reason, piping maintenance is performed periodically, but at this time, the vacuum pump device is stopped, and when the piping maintenance is finished, the vacuum pump device is restarted. However, when a large amount of by-products accumulate in the pump chamber, the resistance to rotation of the pump rotor is great, and the vacuum pump device may not be restarted.

Japanese Unexamined Patent Publication No. 2009-97349

Then, when stopping the operation of the vacuum pump device, a pump stopping method has been proposed in which by-products accumulated in the pump chamber are gradually scraped off by the pump rotor by repeating rotation and stop of the pump rotor (see Patent Document 1). . According to this method, by-products are removed from the pump chamber, and the vacuum pump device can be restarted.

However, this pump stop method may not be accepted by users in that it requires a long time (for example, about 3 hours) to complete and reduces the throughput of manufacturing products such as semiconductor devices.

Accordingly, the present invention provides a vacuum pump capable of reducing deposition of by-products caused by process gas in the pump chamber, preventing unintentional stoppage of the vacuum pump device, and further ensuring restart of the vacuum pump device, and It provides a driving method.

In one aspect, a pump casing having a pump chamber therein, a pump rotor disposed in the pump chamber, a rotating shaft to which the pump rotor is fixed, an electric motor connected to the rotating shaft, a bearing rotatably supporting the rotating shaft, and the above a side cover connected to a pump casing, a heater installed on the side cover, and a heater control unit for intermittently heating the heater while the pump rotor is rotating, wherein the bearing is connected to the side cover, A pump device is provided.

In one aspect, the side cover forms an end face of the pump chamber.

In one aspect, the pump casing forms an end face of the pump chamber.

In one aspect, the vacuum pump device further includes a bearing housing holding the bearing, and the bearing housing is held by the side cover.

In one aspect, the side cover includes a side wall forming an end surface of the pump chamber and a spacer made of the same material as the side wall or a material having a larger linear expansion coefficient than the side wall, and the heater includes the spacer are placed within.

In one aspect, the side cover forms an end surface of the pump chamber and includes a side wall made of the same material as the rotation shaft or a material having a larger linear expansion coefficient than the rotation shaft, and a spacer for holding the bearing, , the heater is disposed within the side wall.

In one aspect, the side cover includes a side wall connected to the pump casing and a spacer made of the same material as the side wall or a material having a larger linear expansion coefficient than the side wall, and the heater is disposed within the spacer has been

In one aspect, the side cover is connected to the pump casing and includes a side wall made of the same material as the rotation shaft or a material having a larger coefficient of linear expansion than the rotation shaft, and a spacer for holding the bearing, A heater is disposed within the side wall.

In one aspect, the vacuum pump device further includes a first temperature sensor for measuring the temperature of the pump casing and a second temperature sensor for measuring the temperature of the side cover, and the heater control unit includes the pump A target temperature is determined based on the temperature of the casing, and the heater is controlled so that the temperature of the side cover reaches the target temperature.

In one aspect, the heater control unit is configured to stop heat generation of the heater or reduce a heat generation temperature of the heater after the temperature of the side cover reaches the target temperature.

In one aspect, the vacuum pump device further includes a displacement sensor for measuring an axial displacement of the bearing, and the heater control unit, when the axial displacement of the bearing reaches a threshold value, controls the heater It is configured to stop the heat generation of

In one aspect, the vacuum pump device further includes a second heater installed in the pump casing.

In one aspect, the vacuum pump device further includes a cooler installed in the pump casing.

In one aspect, a pump rotor disposed in a pump chamber of a pump casing is fixed to a rotating shaft, and the rotating shaft is rotatably supported by a bearing, and the bearing is connected to a side cover connected to the pump casing. A method of operating a vacuum pump device is provided in which a heater provided on the side cover is intermittently heated while a process gas is being exhausted by rotation of a pump rotor.

In one aspect, the side cover forms an end face of the pump chamber.

In one aspect, the pump casing forms an end face of the pump chamber.

In one aspect, the bearing is held in a bearing housing, and the bearing housing is held in the side cover.

In one aspect, the side cover includes a side wall forming an end surface of the pump chamber and a spacer made of the same material as the side wall or a material having a larger linear expansion coefficient than the side wall, and the heater includes the spacer are placed within.

In one aspect, the side cover forms an end surface of the pump chamber and includes a side wall made of the same material as the rotation shaft or a material having a larger linear expansion coefficient than the rotation shaft, and a spacer for holding the bearing, , the heater is disposed within the side wall.

In one aspect, the side cover includes a side wall connected to the pump casing and a spacer made of the same material as the side wall or a material having a larger linear expansion coefficient than the side wall, and the heater is disposed within the spacer has been

In one aspect, the side cover is connected to the pump casing and includes a side wall made of the same material as the rotation shaft or a material having a larger coefficient of linear expansion than the rotation shaft, and a spacer for holding the bearing, A heater is disposed within the side wall.

In one aspect, the driving method further includes determining a target temperature based on the temperature of the pump casing, and controlling the heater so that the temperature of the side cover reaches the target temperature.

In one aspect, the driving method further includes stopping heating of the heater or lowering a heating temperature of the heater after the temperature of the side cover reaches the target temperature.

In one aspect, the driving method further includes stopping heat generation of the heater when the displacement of the bearing in the axial direction reaches a threshold value.

In one aspect, the driving method further includes heating the pump casing by a second heater installed in the pump casing.

In one aspect, the driving method further includes cooling the pump casing by a cooler installed in the pump casing.

When the heater is intermittently heated while the pump rotor rotates, the side cover repeats thermal expansion and contraction, and the rotating shaft reciprocates in the axial direction through the bearing connected to the side cover. Accompanying the reciprocating movement of the rotating shaft in the axial direction, the pump rotor also reciprocates in the axial direction, and the rotating pump rotor can scrape off by-products accumulated in the pump chamber. As a result, the pump rotor can rotate smoothly.

1 is a cross-sectional view showing one embodiment of a vacuum pump device.
2 is an enlarged sectional view showing a side cover, a bearing housing, and a bearing on the exhaust side.
Fig. 3 is a cross-sectional view showing a state in which the pump rotor moves in the axial direction accompanying the thermal expansion of the rotating shaft.
Fig. 4 is a cross-sectional view showing a state in which the pump rotor is moved toward the side cover by thermally expanding the spacer by heat generated by the heater.
5 is a cross-sectional view showing one embodiment provided with a displacement sensor for measuring displacement of a bearing.
6 is a cross-sectional view showing an embodiment of a side cover made of a single material.
Fig. 7 is a cross-sectional view showing an embodiment in which a bearing is directly held by a side cover.
Fig. 8 is a cross-sectional view showing another embodiment in which a bearing is directly held by a side cover.
Fig. 9 is a diagram showing an embodiment of a vacuum pump device provided with a second heater installed in a pump casing.
Fig. 10 is a diagram showing an embodiment of a vacuum pump device having a cooler installed in a pump casing.
Fig. 11 is a cross-sectional view showing another embodiment of the vacuum pump device.
Fig. 12 is a cross-sectional view showing still another embodiment of the vacuum pump device.
Fig. 13 is a cross-sectional view showing still another embodiment of the vacuum pump device.

1 is a cross-sectional view showing one 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 passage. Since vaporized oil does not flow upstream of the dry vacuum pump device, it can be suitably used in semiconductor device manufacturing equipment requiring high cleanliness.

As shown in FIG. 1, the vacuum pump device includes a pump casing 2 having a pump chamber 1 therein, pump rotors 5A to 5E disposed in the pump chamber 1, and pump rotors 5A to 5E. ) is provided with a fixed rotational shaft 7 and an electric motor 8 connected to the rotational shaft 7. The pump rotors 5A to 5E and the rotating shaft 7 may be an integrated structure. Although only one set of pump rotors 5A to 5E and rotational shaft 7 are depicted in FIG. 1, a pair of pump rotors 5A to 5E are disposed in the pump chamber 1, and a pair of rotational shafts 7 are fixed to each. The electric motor 8 is connected to one of the pair of rotation shafts 7. In one embodiment, a pair of electric motors 8 may be connected to a pair of rotation shafts 7, respectively.

Pump rotors 5A to 5E of this embodiment are root-type pump rotors, but in one embodiment, pump rotors 5A to 5E may be claw-type pump rotors. Further, the pump rotors 5A to 5E may be a combination of a root type pump rotor and a claw type pump rotor. The pump rotors 5A to 5E of this embodiment are multi-stage pump rotors, but in one embodiment, the pump rotor may be a single-stage pump rotor.

The vacuum pump device further includes side covers 10A and 10B located outside the pump casing 2 in the axial direction of the rotating shaft 7 . 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 face of the pump casing 2 with screws not shown.

The pump chamber 1 is formed by the inner surface of the pump casing 2 and the inner surface of 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 transported. In one example, the intake port 2a is connected to a process chamber of a semiconductor device manufacturing apparatus, and a vacuum pump device is used to exhaust process gas from the process chamber.

The vacuum pump device further includes a motor housing 14 and a gear housing 16 as housing structures 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 casing 2 and the motor housing 14, and the side cover 10B is located between the pump casing 2 and the gear housing 16.

The motor housing 14 accommodates the motor rotor 8A and the motor stator 8B of the electric motor 8 therein. Inside the gear housing 16, a pair of gears 20 meshing with each other are disposed. Also, in FIG. 1 only one gear 20 is depicted. The electric motor 8 is rotated by a motor driver (not shown), and the rotary shaft 7 on one side to which the electric motor 8 is connected is via a gear 20 to the other rotary shaft 7 to which the electric motor 8 is not connected. ) in the opposite direction.

In one embodiment, a pair of electric motors 8 each connected to a pair of rotational shafts 7 may be provided. The pair of electric motors 8 are synchronously rotated by a motor driver (not shown) in opposite directions, and the pair of rotation shafts 7 and the pair of pump rotors 5A to 5E are synchronously rotated in opposite directions. . The role of the gear 20 in this case is to prevent out of sync rotation of the pump rotor 5 due to sudden external factors.

In the embodiment shown in Fig. 1, the motor housing 14 is disposed outside the side cover 10A and the gear housing 16 is disposed outside the side cover 10B, but the configuration of the vacuum pump device is It is not limited to this embodiment. In one embodiment, the gear housing 16 may be arrange|positioned on the outside of side cover 10A, and the motor housing 14 may be arrange|positioned on the outside of side cover 10B. Moreover, in one embodiment, both the motor housing 14 and the gear housing 16 may be arrange|positioned on the outer side of either side cover 10A or side cover 10B.

When the pump rotors 5A to 5E are rotated by the electric motor 8, gas is sucked into the pump chamber 1 of the pump casing 2 through the intake port 2a. The gas is transported to the exhaust port 2b while being sequentially compressed by the rotating pump rotors 5A to 5E, and is discharged from the pump chamber 1 through the exhaust port 2b.

The rotating shaft 7 is rotatably supported by bearings 17 and 18 . The bearing 17 is held by the bearing housing 24, and the bearing 18 is supported by the side cover 10B. The bearing 17 is connected to the side cover 10A via the bearing housing 24 . More specifically, the bearing housing 24 is held by the side cover 10A, and the positions of the bearing housing 24 and the bearing 17 are fixed by the side cover 10A. Since the inner ring of the bearing 17 is fixed to the rotating shaft 7, the axial position of the portion of the rotating shaft 7 held by the bearing 17 is fixed.

On the other hand, the bearing 18 is supported by the side cover 10B so as to be movable in the axial direction. More specifically, the inner ring of the bearing 18 is fixed to the rotating shaft 7, but the outer ring of the bearing 18 is not fixed to the side cover 10B, but is simply supported by the side cover 10B. . Thus, the bearing 18 is axially movable integrally with the rotating shaft 7 .

Between the side cover 10B and the bearing 18, a bearing housing holding the bearing 18 may be disposed. In this case, the bearing housing is fixed to the side cover 10B, but the outer ring of the bearing 18 is not fixed to the bearing housing, but is simply supported by the bearing housing, and the bearing 18 is connected to the rotating shaft 7. It is possible to move integrally in the axial direction.

During operation of the vacuum pump device, gas is compressed in the course of being conveyed from the intake port 2a to the exhaust port 2b by the pump rotors 5A to 5E. Therefore, the rotating shaft 7 located in the pump chamber 1 thermally expands due to the compression heat of the gas. While the position of the bearing 17 in the axial direction is fixed, since the bearing 18 is movable in the axial direction, the rotary shaft 7 thermally expands in the axial direction starting from the bearing 17, and the thermal expansion of the rotary shaft 7 As a result, the bearing 18 moves in the axial direction.

Fig. 2 is an enlarged sectional view showing the side cover 10A, the bearing housing 24, and the bearing 17 on the exhaust side. As shown in FIG. 2 , the pump casing 2 has a partition wall 36 therein, and the pump rotor 5E is disposed between the partition wall 36 and the side cover 10A. In this embodiment, the side cover 10A is made of the same material as the side wall 31 forming the end face of the pump chamber 1 and the side wall 31, or a material having a larger coefficient of linear expansion than the side wall 31. A spacer 32 is provided. The spacer 32 is positioned between the side wall 31 and the bearing housing 24 . The bearing housing 24 is held by the spacer 32, and the bearing housing 24 is connected to the side wall 31 via the spacer 32.

The vacuum pump device is provided with a heater 35 installed on the side cover 10A. In this embodiment, the heater 35 is disposed in the spacer 32 of the side cover 10A. The spacer 32 is made of a metal having the same material as the side wall 31 and the pump casing 2 or a larger coefficient of linear expansion than the side wall 31 . For example, when the side wall 31 and the pump casing 2 are made of cast iron, the spacer 32 is made of cast iron, or made of stainless steel, aluminum, aluminum alloy, or copper having a higher coefficient of linear expansion than cast iron. It consists of When the heater 35 generates heat, the spacer 32 thermally expands, and the bearing housing 24 held by the spacer 32 moves in the axial direction. In particular, the spacer 32 has a shape surrounding the bearing housing 24 and is easily thermally expanded in the axial direction.

When the temperature of the process gas handled by the vacuum pump device decreases or rises through a reaction within the chamber, solidified by-products may be formed. Such by-products are gradually deposited in the pump chamber 1 along with the operation of the vacuum pump device. 3 is a cross-sectional view showing a state in which the pump rotor 5E moves in the axial direction accompanying the thermal expansion of the rotating shaft 7 . As described above, the high-temperature rotary shaft 7 thermally expands in the axial direction, and as a result, the pump rotor 5E moves in a direction away from the side cover 10A forming the end face of the pump chamber 1. . The by-product 100 is gradually deposited in the gap between the pump rotor 5E and the side cover 10A. Such a by-product 100 inhibits the rotation of the pump rotor 5E, causes the vacuum pump device to stop unintentionally, or prevents the vacuum pump device from restarting.

Then, as shown in FIG. 4, by thermally expanding the spacer 32 by heat generation of the heater 35, the bearing housing 24 and the bearing 17 are moved in the axial direction, and the pump rotor 5E is moved to the side. It moves toward the cover 10A. When the rotating pump rotor 5E moves toward the side cover 10A (the end surface of the pump chamber 1), by-products 100 deposited in the gap between the pump rotor 5E and the side cover 10A scrape off little by little.

When the pump rotor 5E reaches the initial position shown in Fig. 2, heat generation from the heater 35 is stopped. The initial position of the pump rotor 5E is the position of the pump rotor 5E when the entire vacuum pump device is at room temperature. When the heater 35 stops generating heat, the temperature of the spacer 32 gradually decreases, and the spacer 32 gradually contracts. Accompanying the contraction of the spacer 32, the pump rotor 5E moves in a direction away from the side cover 10A, and as shown in FIG. 3, there is a gap between the pump rotor 5E and the side cover 10A. The gap grows. Since the by-product 100 is gradually deposited in this gap, the heater 35 is heated again to thermally expand the spacer 32 . As shown in Fig. 4, the rotating pump rotor 5E moves toward the side cover 10A (the end face of the pump chamber 1) while the gap between the pump rotor 5E and the side cover 10A. The by-products 100 deposited on are scraped off little by little.

Similarly, the by-product 100 deposited between the partition wall 36 and the pump rotor 5E also stops the heat generation of the heater 35 and moves the pump rotor 5E away from the side cover 10A. When moving (in the direction approaching the bulkhead 36), it is scraped off little by little by the rotating pump rotor 5E.

In this way, during operation of the vacuum pump device (i.e., during evacuation of the process gas), the heater 35 repeatedly heats and stops heat, thereby reciprocating the rotating pump rotor 5E in the axial direction, thereby generating a rotating pump. By-products accumulated in the pump chamber 1 are scraped off by the rotor 5E. By the same mechanism, the rotating pump rotors 5A to 5D can also scrape off the by-products accumulated in the pump chamber 1. As a result, by-products are removed from the pump chamber 1, and the pump rotors 5A to 5E can rotate smoothly.

In a conventional pump, since the pump rotor does not reciprocate as described above during operation, a large amount of by-products are deposited near the pump rotor during operation, and a large amount of by-products are drawn into the pump at a certain timing. was abruptly stopped. According to the present invention, by always repeating the reciprocating motion of the pump rotors 5A to 5E, it is possible to create a state in which almost no byproducts are always deposited in the pump chamber 1, especially in the vicinity of the pump rotors 5A to 5E. Therefore, sudden stop of the pump can be prevented.

As shown in FIG. 2 , the vacuum pump device includes a heater control unit 40 that controls heat generation of the heater 35 . The heater controller 40 is configured to cause the heater 35 to generate heat intermittently (cyclically repeat heat generation and stop of heat generation of the heater 35) when the pump rotors 5A to 5E are rotating. The heater controller 40 includes a storage device 40a in which the program is stored, an arithmetic device 40b that executes calculations according to commands included in the program, and a power source 40c that supplies power to the heater 35. are doing The heater control unit 40 includes at least one computer. The storage device 40a includes a main storage device such as a random access memory (RAM) and an auxiliary storage device such as a hard disk drive (HDD) and a solid state drive (SSD). Examples of the arithmetic unit 40b include a CPU (central processing unit) and a GPU (graphics processing unit). However, the specific configuration of the heater control unit 40 is not limited to these examples.

The vacuum pump device further includes a first temperature sensor 45 for measuring the temperature of the pump casing 2 and a second temperature sensor 46 for measuring the temperature of the side cover 10A. The first temperature sensor 45 is fixed to the pump casing 2 . The first temperature sensor 45 may be fixed to the outer surface of the pump casing 2 or may be embedded in the pump casing 2 . This 1st temperature sensor 45 is provided in order to measure the temperature of the rotating shaft 7 indirectly. That is, from the temperature of the pump casing 2 measured by the first temperature sensor 45, the temperature of the rotating shaft 7 disposed therein can be estimated.

The second temperature sensor 46 is fixed to the side cover 10A. The 2nd temperature sensor 46 may be fixed to the outer surface of 10 A of side covers, or may be embedded in 10 A of side covers. In the embodiment shown in FIGS. 2 to 4 , the second temperature sensor 46 is fixed to the spacer 32 of the side cover 10A. Therefore, the second temperature sensor 46 can measure the temperature of the side cover 10A (more specifically, the temperature of the spacer 32). The second temperature sensor 46 may be embedded in the spacer 32 .

The heater controller 40 is configured to determine the target temperature of the spacer 32, that is, the target temperature of the side cover 10A, based on the temperature of the pump casing 2 measured by the first temperature sensor 45. has been Since the temperature of the pump casing 2 indirectly indicates the temperature of the rotating shaft 7, the degree of thermal expansion of the rotating shaft 7 at the temperature of the pump casing 2, that is, the axial direction from the initial position of the pump rotor 5E travel distance can be estimated. Therefore, the heater control unit 40 can determine the target temperature of the spacer 32 required to return the pump rotor 5E, which has moved by the thermal expansion of the rotating shaft 7, to the initial position.

The heater controller 40 determines the temperature of the pump casing 2, the thickness of the spacer 32 in the axial direction, and the coefficient of linear expansion of the spacer 32 to return the pump rotor 5E to the initial position. The target temperature of the spacer 32 is determined. The relationship between the movement distance of the pump rotor 5E and the temperature of the spacer 32 may be determined by experiment or simulation, and the target temperature of the spacer 32 may be determined from the obtained relationship.

The heater controller 40 is configured to control the heater 35 so that the temperature of the spacer 32 reaches the determined target temperature. The temperature of the spacer 32 is measured by the second temperature sensor 46, and the spacer 32 is heated to the target temperature. As the spacer 32 is heated, the bearing housing 24, the bearing 17, the rotating shaft 7 and the pump rotor 5E are moved in the axial direction. Then, when the spacer 32 is heated to the target temperature, the pump rotor 5E returns to the initial position shown in FIG. 4 . After that, the heater control unit 40 stops heat generation of the heater 35 . In one embodiment, after the spacer 32 is heated to the target temperature, the heater control unit 40 may lower the heating temperature of the heater 35 . In addition, the heater control unit 40 may stop the heat generation of the heater 35 after lowering the heat generation temperature of the heater 35 .

In this way, the heater controller 40 causes the heater 35 to generate heat intermittently, causing the pump rotor 5E to reciprocate between the initial position shown in FIG. 4 and the thermal expansion position shown in FIG. 3 . Thereby, the other pump rotors 5A to 5D also reciprocate in the axial direction in the same way. Since the pump rotors 5A to 5E axially reciprocate into the pump chamber 1 while rotating, the pump rotors 5A to 5E can scrape off by-products accumulated in the pump chamber 1.

In one embodiment, as shown in FIG. 5 , the vacuum pump device is provided with a displacement sensor 49 for measuring the axial displacement of the bearing 17 . The displacement sensor 49 is installed on the side wall 31 of the side cover 10A, and is disposed toward the bearing housing 24 holding the bearing 17 . Accordingly, the displacement sensor 49 measures the axial displacement of the bearing 17 by measuring the axial displacement of the bearing housing 24 . In one embodiment, the displacement sensor 49 may be arranged to directly measure the axial displacement of the bearing 17 .

The displacement sensor 49 is electrically connected to the heater controller 40 . The heater controller 40 is configured to stop heat generation of the heater 35 when the displacement of the bearing 17 in the axial direction reaches a threshold value. Thus, by controlling the heat generation of the heater 35 based on the axial displacement of the bearing 17, contact of the pump rotor 5E with the inner surface of the side cover 10A (the end surface of the pump chamber 1) is prevented. It can be prevented.

In one embodiment, as shown in FIG. 6, 10 A of side covers may be comprised from a single material. More specifically, a part of the side cover 10A forms an end surface of the pump chamber 1, and the other part of the side cover 10A holds the bearing housing 24. The side cover 10A is made of the same material as the material of the pump casing 2 or a material having a larger linear expansion coefficient than the pump casing 2 . For example, when the pump casing 2 is made of cast iron, the entirety of the side cover 10A is made of cast iron, or stainless steel, aluminum, aluminum alloy, or copper having a larger linear expansion coefficient than the pump casing 2. consists of Even in the embodiment shown in FIG. 6 , the rotating pump rotors 5A to 5E can scrape off by-products accumulated in the pump chamber 1 by repeating heating and stopping of heating by the heater 35 .

In one embodiment, as shown in FIG. 7 , the bearing housing 24 may be omitted. In the embodiment shown in FIG. 7 , the bearing 17 is directly held by the side cover 10A. More specifically, the bearing 17 is directly held by the spacer 32 of the side cover 10A. In addition, in one Embodiment, as shown in FIG. 8, 10 A of side covers are comprised from a single material, and the bearing housing 24 does not need to be present. The embodiment shown in Fig. 8 is a combination of the embodiment shown in Fig. 6 and the embodiment shown in Fig. 7, and the bearing 17 is directly held by the side cover 10A. Even in the embodiment shown in FIGS. 7 and 8 , the rotating pump rotors 5A to 5E can scrape off by-products accumulated in the pump chamber 1 by repeating heating and stopping of heating by the heater 35. .

In one embodiment, as shown in FIG. 9 , in order to prevent deposition of by-products in the pump chamber 1 due to a decrease in the temperature of the process gas, the vacuum pump device is installed in the pump casing 2. Two heaters 50 may be further provided. Some process gases generate by-products as the temperature of the process gas rises. When used for the purpose of exhausting such a process gas, the vacuum pump device may further include a cooler 51 installed in the pump casing 2 as shown in FIG. 10 . The cooler 51 is, for example, a water-cooled cooler. The second heater 50 shown in FIG. 9 and the cooler 51 shown in FIG. 10 may be installed on the outer surface of the pump casing 2 or may be embedded in the pump casing 2 .

According to the embodiment shown in FIGS. 9 and 10 , the reciprocating movement of the pump rotors 5A to 5E in the axial direction by the intermittent operation of the heater 35 and the combination of the second heater 50 or the cooler 51 Thus, accumulation of by-products in the pump chamber 1 can be prevented reliably.

11 is a cross-sectional view showing another embodiment of the vacuum pump device. As shown in FIG. 11 , in the vacuum pump device of the present embodiment, lubricating oil 110 for lubricating and cooling the bearing 17 is stored at the bottom of the motor housing 14 . Configurations and operations of the present embodiment, which are not particularly described, are the same as those of the embodiment described with reference to FIGS.

The vacuum pump device of the present embodiment includes a rotary disc 60 for supplying lubricating oil 110 to a bearing 17, and a partition wall 62 disposed between an electric motor 8 and a bearing housing 24. are doing The rotation disc 60 is connected to each of the pair of rotation shafts 7 and rotates together with the rotation shaft 7 . In one embodiment, the rotation disc 60 is connected to one of the pair of rotation shafts 7, and may rotate together with the connected rotation shaft 7. The lubricating oil 110 is scooped up when the rotary disc 60 rotates, and is supplied to the bearing 17 .

The partition wall 62 is fixed to the inner wall of the motor housing 14 and has a through hole (not shown) through which the rotary shaft 7 passes. The partition wall 62 is configured to partition a space where the lubricating oil 110 is stored and a space where the electric motor 8 is accommodated, and prevents the lubricating oil 110 from contacting the electric motor 8. is prepared for

The lubricating oil 110 in the motor housing 14 is always in contact with the spacer 32 of the side cover 10A. When the heater 35 is arranged in the spacer 32, the temperature of the lubricating oil 110 rises due to the heat of the heater 35, and the cooling effect of the bearing 17 may not be sufficiently obtained. So, in embodiment shown in FIG. 11, the heater 35 is arrange|positioned in the side wall 31 of 10 A of side covers.

The side cover 10A includes a side wall 31 forming an end face of the pump chamber 1 and a spacer 32 holding the bearing 17 therein. The spacer 32 is connected to the side wall 31 and is located between the side wall 31 and the bearing housing 24 . The bearing housing 24 is held by the spacer 32, and the bearing housing 24 is connected to the side wall 31 via the spacer 32. Bearing 17 is connected to spacer 32 via bearing housing 24 . The spacer 32 holds the bearing 17 via the bearing housing 24 .

The side wall 31 is made of a metal that is the same as the material of the rotating shaft 7 or has a larger coefficient of linear expansion than the rotating shaft 7 . For example, when the rotating shaft 7 is made of cast iron, the side wall 31 is made of cast iron or made of stainless steel, aluminum, aluminum alloy or copper having a higher coefficient of linear expansion than cast iron. In one embodiment, the side wall 31 is made of a metal that is the same as the material of the pump casing 2 and/or the spacer 32 or has a larger linear expansion coefficient than the pump casing 2 and/or the spacer 32. It can be.

When the heater 35 generates heat, the side wall 31 thermally expands, and the spacer 32 connected to the side wall 31 moves in the axial direction. Thereby, the bearing housing 24 and the bearing 17 held by the spacer 32 move in the axial direction, and the pump rotor 5E moves toward the side cover 10A. When the rotating pump rotor 5E moves toward the side cover 10A (the end surface of the pump chamber 1), by-products deposited in the gap between the pump rotor 5E and the side cover 10A are scraped little by little. can drop

When heat generation by the heater 35 is stopped, the temperature of the side wall 31 gradually decreases, and the side wall 31 gradually contracts. Accompanying contraction of the side wall 31, the pump rotor 5E moves in a direction away from the side cover 10A, and the gap between the pump rotor 5E and the side cover 10A increases. Also in the embodiment shown in FIG. 11 , as in the embodiment described with reference to FIGS. 3 and 4 , when the heater 35 repeats heat generation and stoppage of heat, the rotating pump rotors 5A to 5E move to the pump chamber 1 By-products deposited inside can be scraped off.

Fig. 12 is a cross-sectional view showing still another embodiment of the vacuum pump device. Configurations and operations of the present embodiment, which are not particularly described, are the same as those of the embodiment described with reference to FIGS. As shown in FIG. 12 , the pump casing 2 of the present embodiment has casing side walls 70A and 70B forming end faces of the pump chamber 1, and the pump casing 2 has the pump chamber 1 ) covers the entire area. The pump chamber 1 is formed by the inner surface of the pump casing 2 . Side covers 10A and 10B are provided on both sides of the pump casing 2 and are connected to the pump casing 2 . More specifically, the side wall 31 of the side cover 10A is connected to the casing side wall 70A of the pump casing 2, and the side cover 10B is the casing side wall 70B of the pump casing 2. ) is connected. The rotating shaft 7 extends through casing side walls 70A and 70B of the pump casing 2 .

The side cover 10A is a spacer made of a side wall 31 connected to the casing side wall 70A of the pump casing 2 and a material that is the same as the side wall 31 or a material having a larger coefficient of linear expansion than the side wall 31. (32) is provided. The spacer 32 is positioned between the side wall 31 and the bearing housing 24 . The bearing housing 24 is held by the spacer 32, and the bearing housing 24 is connected to the side wall 31 via the spacer 32. In this embodiment, the heater 35 is disposed in the spacer 32 of the side cover 10A. Also in the embodiment shown in FIG. 12, the rotating pump rotors 5A to 5E can scrape off by-products accumulated in the pump chamber 1 by repeating heating and stopping of heating by the heater 35.

Fig. 13 is a cross-sectional view showing still another embodiment of the vacuum pump device. In the vacuum pump device of the present embodiment, lubricating oil 110 for lubricating and cooling the bearing 17 is stored at the bottom of the motor housing 14, similarly to the embodiment described with reference to FIG. 11 . Configurations and operations of the present embodiment, which are not particularly described, are the same as those of the embodiment described with reference to FIG. 11, and therefore, duplicate descriptions thereof are omitted. As shown in FIG. 13 , the pump casing 2 of the present embodiment has casing side walls 70A and 70B forming end faces of the pump chamber 1, and the pump casing 2 has the pump chamber 1 ) covers the entire area. The pump chamber 1 is formed by the inner surface of the pump casing 2 . Side covers 10A and 10B are provided on both sides of the pump casing 2 and are connected to the pump casing 2 . More specifically, the side wall 31 of the side cover 10A is connected to the casing side wall 70A of the pump casing 2, and the side cover 10B is the casing side wall 70B of the pump casing 2. ) is connected. The rotating shaft 7 extends through casing side walls 70A and 70B of the pump casing 2 .

The side cover 10A includes a side wall 31 connected to the casing side wall 70A of the pump casing 2 and a spacer 32 holding the bearing 17 . The side wall 31 is made of a metal that is the same as the material of the rotating shaft 7 or has a larger coefficient of linear expansion than the rotating shaft 7 . In this embodiment, the heater 35 is disposed in the side wall 31 of the side cover 10A. Also in the embodiment shown in FIG. 13, the rotating pump rotors 5A to 5E can scrape off the by-products accumulated in the pump chamber 1 by repeating the heating and stopping of the heating by the heater 35.

The above-described embodiment was described for the purpose of being able to implement the present invention by those skilled in the art in the technical field to which the present invention belongs. Various modified examples of the above embodiments can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments as well. Therefore, this invention is not limited to the described embodiment, but is interpreted in the widest range according to the technical idea defined by the claim.

1: Pump room
2: pump casing
2a: intake
2b: exhaust vent
5A to 5E: pump rotor
7: axis of rotation
8: electric motor
10A, 10B: Side cover
14: motor housing
16: gear housing
17, 18: bearing
20: gear
24: bearing housing
31: side wall
32: spacer
35: heater
40: heater control unit
45: first temperature sensor
46: second temperature sensor
49: displacement sensor
50: second heater
51: cooler
60: rotating disc
62: partition wall
70A, 70B: casing sidewall
100: by-products
110: lubricant

Claims (26)

A pump casing having a pump chamber therein;
a pump rotor disposed in the pump chamber;
A rotating shaft to which the pump rotor is fixed;
an electric motor connected to the rotating shaft;
a bearing rotatably supporting the rotating shaft;
a side cover connected to the pump casing;
A heater installed on the side cover;
A heater control unit for intermittently heating the heater when the pump rotor is rotating,
The bearing is connected to the side cover, the vacuum pump device. According to claim 1,
The side cover forms an end face of the pump chamber. According to claim 1,
The pump casing forms an end face of the pump chamber. According to claim 1,
The vacuum pump device further includes a bearing housing for holding the bearing,
The vacuum pump device according to claim 1 , wherein the bearing housing is held by the side cover. According to claim 2,
The side cover,
a side wall forming an end surface of the pump chamber;
A spacer made of the same material as the side wall or a material having a larger linear expansion coefficient than the side wall,
The vacuum pump device according to claim 1 , wherein the heater is disposed within the spacer. According to claim 2,
The side cover,
a side wall forming an end face of the pump chamber and made of the same material as the rotating shaft or a material having a larger coefficient of linear expansion than the rotating shaft;
A spacer for holding and supporting the bearing is provided,
The vacuum pump device according to claim 1 , wherein the heater is disposed within the side wall. According to claim 3,
The side cover,
a side wall connected to the pump casing;
A spacer made of the same material as the side wall or a material having a larger linear expansion coefficient than the side wall,
The vacuum pump device according to claim 1 , wherein the heater is disposed within the spacer. According to claim 3,
The side cover,
a side wall connected to the pump casing and made of the same material as the rotating shaft or a material having a larger coefficient of linear expansion than the rotating shaft;
A spacer for holding and supporting the bearing is provided,
The vacuum pump device according to claim 1 , wherein the heater is disposed within the side wall. According to claim 1,
A first temperature sensor for measuring the temperature of the pump casing;
Further comprising a second temperature sensor for measuring the temperature of the side cover,
The heater control unit determines a target temperature based on the temperature of the pump casing, and controls the heater so that the temperature of the side cover reaches the target temperature. According to claim 9,
The vacuum pump device according to claim 1 , wherein the heater control unit is configured to stop heat generation of the heater or reduce a heat generation temperature of the heater after the temperature of the side cover reaches the target temperature. According to claim 1,
Further comprising a displacement sensor for measuring an axial displacement of the bearing,
The vacuum pump device according to claim 1 , wherein the heater control unit is configured to stop heat generation of the heater when the axial displacement of the bearing reaches a threshold value. According to claim 1,
A vacuum pump device further comprising a second heater installed in the pump casing. According to claim 1,
A vacuum pump device further comprising a cooler installed in the pump casing. The pump rotor disposed in the pump chamber of the pump casing is fixed to the rotating shaft,
The rotating shaft is rotatably supported by bearings,
The bearing is connected to a side cover connected to the pump casing, and when the process gas is exhausted by rotation of the pump rotor, a heater installed in the side cover intermittently generates heat. According to claim 14,
The method of operating a vacuum pump device, wherein the side cover forms an end face of the pump chamber. According to claim 14,
The method of operating a vacuum pump device, wherein the pump casing forms an end face of the pump chamber. According to claim 14,
The bearing is held in a bearing housing,
The method of operating a vacuum pump device, wherein the bearing housing is held by the side cover. According to claim 15,
The side cover,
a side wall forming an end surface of the pump chamber;
A spacer made of the same material as the side wall or a material having a larger linear expansion coefficient than the side wall,
The method of operating a vacuum pump device, wherein the heater is disposed within the spacer. According to claim 15,
The side cover,
a side wall forming an end face of the pump chamber and made of the same material as the rotating shaft or a material having a larger coefficient of linear expansion than the rotating shaft;
A spacer for holding and supporting the bearing is provided,
The method of operating a vacuum pump device, wherein the heater is disposed within the side wall. According to claim 16,
The side cover,
a side wall connected to the pump casing;
A spacer made of the same material as the side wall or a material having a larger linear expansion coefficient than the side wall,
The method of operating a vacuum pump device, wherein the heater is disposed within the spacer. According to claim 16,
The side cover,
a side wall connected to the pump casing and made of the same material as the rotating shaft or a material having a larger coefficient of linear expansion than the rotating shaft;
A spacer for holding and supporting the bearing is provided,
The method of operating a vacuum pump device, wherein the heater is disposed within the side wall. According to claim 14,
determining a target temperature based on the temperature of the pump casing;
The method of operating the vacuum pump device further comprising controlling the heater so that the temperature of the side cover reaches the target temperature. The method of claim 22,
After the temperature of the side cover reaches the target temperature, stopping the heat generation of the heater or reducing the heating temperature of the heater, the operating method of the vacuum pump device. According to claim 14,
and stopping heat generation of the heater when the axial displacement of the bearing reaches a critical value. According to claim 14,
The method of operating a vacuum pump device further comprising heating the pump casing by a second heater installed in the pump casing. According to claim 14,
The method of operating a vacuum pump device further comprising cooling the pump casing by a cooler installed in the pump casing.

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