VACUUM PUMP AND VACUUM PUMP SYSTEM

Description

TECHNICAL FIELD

The present invention relates to a vacuum pump and a vacuum pump system.

BACKGROUND ART

A turbomolecular pump is used as a vacuum pump for ultra-high vacuum applications and the like. In a turbomolecular pump, since a rotor is rotated at high speed, the temperature of the rotor rises, causing it to become hot. Such a temperature increase may cause distortion in the rotor, leading to a decline in pump function. Therefore, in turbomolecular pumps, the temperature of the rotor is measured and monitored (see, for example, Patent Literature 1).

In the turbomolecular pump disclosed in Patent Literature 1, a change in inductance due to the Curie temperature of a ferromagnetic material is measured by a magnetic circuit to detect the rotor temperature based on whether or not the rotating body has exceeded a predetermined temperature threshold.

CITATION LIST

Patent Literature

[Patent Literature 1] Japanese Unexamined Patent Application Publication No. 2010-90903

SUMMARY OF INVENTION

Technical Problem

Meanwhile, some users desire to increase the process gas flow rate for a short period. However, if the rotational speed of the rotor is increased to accommodate the increased process gas flow rate, the rotor temperature may rise and exceed the aforementioned temperature threshold.

Although the aforementioned temperature threshold is set with a margin, allowing for operation without causing rotor distortion during a short-term increase in process gas flow rate, the configuration in Patent Literature 1 only detects whether the temperature threshold has been exceeded. Therefore, even when operating in a manner that would not cause rotor distortion, such as when the temperature threshold is exceeded for only a short time, the operation of the turbomolecular pump had to be stopped once the temperature threshold was surpassed. Thus, in order to increase the process gas flow rate, it is required to continuously acquire the temperature of the rotor.

An object of the present invention is to provide a vacuum pump and a vacuum pump system capable of continuously acquiring the temperature of a rotor.

Solution to Problem

A vacuum pump according to one aspect of the present invention comprises a rotor, a shaft, a radial housing, and a radiation temperature sensor. The rotor includes a plurality of rotor blades. The shaft is fixed to the rotor and is not subjected to plating treatment. The radial housing is disposed so as to surround the periphery of the shaft. The radiation temperature sensor is disposed in the radial housing and measures the temperature of the shaft.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a vacuum pump and a vacuum pump system capable of continuously acquiring the temperature of a rotor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing the configuration of a vacuum pump system according to an embodiment.

FIG. 2 is an enlarged view of the vicinity of the end of the shaft of FIG. 1.

FIG. 3 is an enlarged view of section S in FIG. 2.

FIG. 4 is an exploded view of FIG. 2.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a vacuum pump and a vacuum pump system according to an embodiment of the present disclosure will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a vacuum pump system 1 according to an embodiment. The vacuum pump system 1 of the present embodiment includes a vacuum pump 100, a controller 110, and a display device 120. The vacuum pump 100 evacuates gas from a space to be evacuated. The controller 110 receives output from a thermopile sensor 41, which will be described later, and determines the temperature of a rotor 21 based on the detected value of the thermopile sensor 41. The display device 120 is connected to the controller 110 and displays the temperature of the rotor 21.

The vacuum pump 100 includes a turbine section P1 and a drag pump section P2. The turbine section P1 constitutes a turbomolecular pump. The drag pump section P2 constitutes a threaded groove pump. The vacuum pump 100 is connected to an evacuation target device that includes a space to be evacuated. Gas from the space to be evacuated is evacuated by the turbine section P1, then by the drag pump section P2, and is discharged to the outside of the vacuum pump 100.

As shown in FIG. 1, the vacuum pump 100 includes a housing 2, a rotating body unit 3, a motor 4, a plurality of stator blade sets 5, and a stator cylindrical portion 6. The housing 2 accommodates the rotating body unit 3, the motor 4, the plurality of stator blade sets 5, and the stator cylindrical portion 6.

The housing 2 has a casing 7, a base 8, and a fixing flange 9. The housing 2 is formed, for example, of an aluminum alloy, but is not limited thereto and may be formed of another metal such as iron. The casing 7 is a cylindrical member having a fixing flange 9 at one end.

The casing 7 accommodates the plurality of stator blade sets 5 and the rotating body unit 3. The casing 7 has a first end portion 11, a second end portion 12, and a side surface 13.

The first end portion 11 is attached to the evacuation target device. The first end portion 11 is provided with an intake port 11a. The second end portion 12 is located on the opposite side of the fixing flange 9 on an axis A, which is the center of the rotating body unit 3. The second end portion 12 is connected to the base 8. The side surface 13 is provided between the first end portion 11 and the second end portion 12. A first internal space S1 is formed inside the casing 7.

The base 8 is connected to the casing 7. The base 8 has a base main body 14 and a radial housing 15. The base main body 14 is disposed so as to close an opening on the second end portion 12 side of the casing 7. The base main body 14 houses the stator cylindrical portion 6 and a rotor cylindrical portion 23 provided in the rotating body unit 3. The base main body 14 has a base end portion 16, a bottom surface 17, and a side surface 18.

The base end portion 16 is the end of the base main body 14 on the casing 7 side. The base main body 14 is connected to the second end portion 12 of the casing 7 at the base end portion 16. The connection between the casing 7 and the base 8 shall include the joining of separate members, and also the continuation of different parts within an integral member. The bottom surface 17 is the surface of the base main body 14 on the side opposite to the intake port 11a. The side surface 18 is provided from the outer peripheral edge of the bottom surface 17 toward the casing 7 up to the base end portion 16. An exhaust port 18a is formed in the side surface 18. A connector 19 for connecting to an exhaust pipe is disposed at the exhaust port 18a. A second internal space S2 is formed inside the base main body 14. The second internal space S2 communicates with the first internal space S1.

The radial housing 15 protrudes from the base main body 14 along the axis A to the inside of the casing 7. The radial housing 15 is substantially cylindrical. The radial housing 15 is disposed around the periphery of a shaft 20 of the rotating body unit 3, which will be described later. The radial housing 15 covers the shaft 20 in a direction perpendicular to the axis A. An end face 15a is disposed at the tip (intake port 11a side) of the radial housing 15. The end face 15a is formed perpendicular to the axis A.

The fixing flange 9 is connected to the casing 7. The fixing flange 9 protrudes from the casing 7. The fixing flange 9 is fixed to the evacuation target device by bolts. Note that “connection” shall include the joining of separate members. Furthermore, “connection” shall include the continuation of different parts within an integral member.

The rotating body unit 3 has a shaft 20 and a rotor 21. The shaft 20 extends along an axis A, which is the center of rotation of the rotating body unit 3. In the following description, in the direction along the axis A, the direction from the casing 7 toward the base 8 is defined as downward, and the opposite direction is defined as upward.

FIG. 2 is an enlarged view of the vicinity of the upper end of the shaft 20. The shaft 20 is formed, for example, of chromium-molybdenum steel. The shaft 20 is not subjected to plating treatment. As shown in FIG. 1 and FIG. 2, the shaft 20 has a shaft main body 31, a protruding portion 32, and a convex portion 33. The shaft main body 31 is cylindrical. The shaft main body 31 is inserted inside the radial housing 15. The upper part of the shaft main body 31 protrudes from the radial housing 15. The protruding portion 32 is disposed at the upper end of the shaft main body 31. The protruding portion 32 protrudes from the shaft main body 31 in a direction perpendicular to the axis A at the upper end of the shaft main body 31. The protruding portion 32 is formed over the entire circumference of the shaft main body 31. The protruding portion 32 is disposed outside the radial housing 15.

The protruding portion 32 is disposed on the upper side of the radial housing 15. The protruding portion 32 faces the end face 15a on the exhaust upstream side (upper side) of the radial housing 15. A surface 32a of the protruding portion 32 on the base 8 side faces the end face 15a. The convex portion 33 protrudes upward at the center of the upper end face of the shaft main body 31.

As shown in FIG. 1, the vacuum pump 100 includes a protection bearing 34 and a plurality of bearings 35A-35C. The protection bearing 34 functions as a touchdown bearing that restricts radial runout of the upper side of the shaft 20. The protection bearing 34 is attached to the radial housing 15 of the base 8. In a state where the shaft 20 is in steady rotation, the shaft 20 and the protection bearing 34 are not in contact. When a large external disturbance is applied, or when the whirling of the shaft 20 becomes large during acceleration or deceleration of rotation, the shaft 20 contacts the inner surface of the inner ring of the protection bearing 34. For the protection bearing 34, a ball bearing or the like can be used, for example.

The plurality of bearings 35A-35C rotatably support the rotating body unit 3. The plurality of bearings 35A-35C are attached to the radial housing 15 of the base 8. The plurality of bearings 35A-35C include, for example, magnetic bearings. However, the plurality of bearings 35A-35C may include other types of bearings such as ball bearings.

The rotor 21 is formed, for example, of an aluminum alloy. The surface of the rotor 21 is subjected to plating treatment to provide durability against corrosive gases. The rotor 21 has a rotor blade portion 22 and a rotor cylindrical portion 23. The rotor blade portion 22 is connected to the shaft 20. The shaft 20 is disposed at the center of rotation of the rotor blade portion 22. The rotor blade portion 22 has a fixing portion 24, a rotor blade attachment portion 25, and a plurality of stages of rotor blade sets 26.

The fixing portion 24 is disk-shaped. The fixing portion 24 is fixed to the shaft main body 31 of the shaft 20 by bolts 27. The fixing portion 24 is disposed on the upper side of the protruding portion 32. As shown in FIG. 2, a through-hole is formed in the center of the fixing portion 24 along the axis A, and the convex portion 33 of the shaft 20 is inserted into the through-hole from below. The fixing portion 24 is connected to the protruding portion 32 on the exhaust upstream side.

The rotor blade attachment portion 25 is disposed around the periphery of the fixing portion 24. The rotor blade attachment portion 25 is cylindrical with the axis A as its center. An end portion 28 of the rotor blade attachment portion 25 on the base 8 side is connected to the rotor cylindrical portion 23. An end portion 29 of the rotor blade attachment portion 25, which is opposite to the end portion 28, is located above the fixing portion 24.

The plurality of stages of rotor blade sets 26 are attached to the outside of the rotor blade attachment portion 25. The plurality of stages of rotor blade sets 26 are arranged at intervals from each other in the direction along the axis A. Each rotor blade set 26 includes a plurality of rotor blades 261. Although not shown, each of the plurality of rotor blades 261 extends radially with the shaft 20 as the center. In the drawings, only one of the plurality of rotor blade sets 26 and one of the plurality of rotor blades 261 are denoted by reference numerals, and the reference numerals for the other rotor blade sets 26 and other rotor blades 261 are omitted.

The rotor cylindrical portion 23 is connected to the end portion 28 of the rotor blade attachment portion 25. The rotor cylindrical portion 23 is disposed below the rotor blade portion 22. The rotor cylindrical portion 23 is cylindrical and extends in the direction along the axis A. The rotor cylindrical portion 23 is disposed on the outer peripheral side of the radial housing 15 so as to surround the radial housing 15.

The motor 4 rotationally drives the rotating body unit 3. As the motor 4, for example, a DC brushless motor is used. The motor 4 has a motor rotor and a motor stator. For example, the motor rotor is attached to the shaft 20. The motor stator is attached to the radial housing 15 of the base 8. The motor stator is disposed facing the motor rotor.

The plurality of stages of stator blade sets 5 are connected to the inner surface of the casing 7. The plurality of stages of stator blade sets 5 are disposed at intervals from each other in the direction along the axis A. Each of the plurality of stages of stator blade sets 5 is disposed between the plurality of stages of rotor blade sets 26. Each stator blade set 5 includes a plurality of stator blades 51. Although not shown, each of the plurality of stator blades 51 extends radially with the shaft 20 as the center.

The plurality of stages of rotor blade sets 26 and the plurality of stages of stator blade sets 5 constitute a turbine section P1 (turbomolecular pump). In the drawings, only one of the plurality of stator blade sets 5 and one of the plurality of stator blades 51 are denoted by reference numerals, and the reference numerals for the other stator blade sets 5 and other stator blades 51 are omitted.

The stator cylindrical portion 6 is disposed on the radially outer side of the rotor cylindrical portion 23. The stator cylindrical portion 6 is connected to the base 8. The stator cylindrical portion 6 is disposed facing the rotor cylindrical portion 23 in the radial direction of the rotor cylindrical portion 23.

A spiral thread groove is provided on the inner peripheral surface of the stator cylindrical portion 6. The rotor cylindrical portion 23 and the stator cylindrical portion 6 constitute a drag pump section P2 (threaded groove pump). Note that the spiral thread groove may be provided on the outer peripheral surface of the rotor cylindrical portion 23 instead of the inner peripheral surface of the stator cylindrical portion 6.

FIG. 3 is an enlarged view of section S in FIG. 2. The vacuum pump 100 includes a thermopile sensor 41, a sensor casing 42, and a sensor cover 43. FIG. 4 is an exploded perspective view showing the thermopile sensor 41, the sensor casing 42, the sensor cover 43, and the shaft 20 disassembled from the radial housing 15.

The thermopile sensor 41 measures the temperature of the shaft 20. The thermopile sensor 41 detects infrared rays emitted from the shaft 20 and transmits a detected value to the controller 110. The thermopile sensor 41 is disposed in the radial housing 15. As shown in FIG. 3 and FIG. 4, a hole 15b is formed in the end face 15a of the radial housing 15 parallel to the axis A. The thermopile sensor 41 is inserted into the hole 15b. The thermopile sensor 41 faces the protruding portion 32 of the shaft 20 in the direction along the axis A. An infrared detection surface 41a of the thermopile sensor 41 faces upward. The detection surface 41a is a surface that receives infrared rays. The detection surface 41a faces the surface 32a of the protruding portion 32 in the direction of the axis A. The detection surface 41a of the thermopile sensor 41 and the end face 15a are disposed on substantially the same plane.

The sensor casing 42 is formed, for example, of an aluminum alloy. The sensor casing 42 is disposed so as to cover the thermopile sensor 41. The sensor casing 42 is disposed in the space between the surface 32a of the protruding portion 32 and the end face 15a. The sensor casing 42 is fixed to the end face 15a of the radial housing 15, for example, by bolts (not shown). A gap is provided between the sensor casing 42 and the surface 32a, and the sensor casing 42 is not in contact with the surface 32a. As shown in FIG. 3, a through-hole 44 is formed in the sensor casing 42 parallel to the axis A. The through-hole 44 is disposed so as to face the detection surface 41a of the thermopile sensor 41. The detection surface 41a and the surface 32a of the protruding portion 32 face each other via the through-hole 44. Infrared rays from the protruding portion 32 of the shaft 20 pass through the through-hole 44 and enter the detection surface 41 a. As shown in FIG. 3, the through-hole 44 includes a large-diameter portion 44a and a small-diameter portion 44b. The large-diameter portion 44a is a portion of the through-hole 44 on the radial housing 15 side. The small-diameter portion 44b is a portion of the through-hole 44 on the protruding portion 32 side of the shaft 20. A step surface 44c is formed between the large-diameter portion 44a and the small-diameter portion 44b. The step surface 44c is disposed parallel to the end face 15a. The entire projected figure obtained by projecting the space of the small-diameter portion 44b onto the surface 32a of the protruding portion 32 along the axial direction A is included in the surface 32a. In other words, in the direction of the axis A, the entirety of the small-diameter portion 44b faces the surface 32a of the protruding portion 32. By thus arranging the through-hole 44 of the sensor casing 42 between the detection surface 41a and the surface 32a of the protruding portion 32, it is possible to suppress infrared rays from components other than the shaft 20 (for example, the rotor 21) from entering the detection surface 41a.

The sensor cover 43 is disposed within the large-diameter portion 44a of the through-hole 44. The sensor cover 43 is disposed on the step surface 44c. The sensor cover 43 is formed, for example, of quartz glass. The sensor cover 43 is bonded to the step surface 44c, for example, with an adhesive. The sensor cover 43 is provided to protect the thermopile sensor 41 when a corrosive gas is used.

The controller 110 includes a processor and a storage device. The processor is, for example, a CPU (Central Processing Unit). Alternatively, the processor may be a processor different from a CPU. The processor executes processing for controlling the vacuum pump 100 according to a program. The storage device includes a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory). The storage device may also include an auxiliary storage device such as a hard disk or an SSD (Solid State Drive). The storage device is an example of a non-transitory computer-readable recording medium. The storage device stores programs and data for controlling the vacuum pump 100. The storage device stores, for example, data of a predetermined threshold and a conversion table, which will be described later.

The controller 110 determines the temperature of the rotor 21 based on the detected value of the thermopile sensor 41. The controller 110 stores a conversion table for determining the temperature of the rotor 21 from the detected value of the thermopile sensor 41. Although the shaft 20 and the rotor 21 are in contact with each other, the detected value of the thermopile sensor 41 is the temperature of the shaft 20 formed of chromium-molybdenum steel, and is therefore different from the temperature of the rotor 21 formed of an aluminum alloy. A conversion table is obtained in advance by actual measurement of the relationship between the detected value of the thermopile sensor 41 and the temperature of the rotor 21, and this conversion table is stored in the controller 110 in advance. The conversion table is a table showing the temperature of the rotor for each temperature of the detected value.

The controller 110 determines the temperature of the rotor 21 from the detected value of the thermopile sensor 41 using the stored conversion table. The controller 110 causes the display device 120 to display the determined temperature of the rotor 21. The controller 110 continuously receives detected values from the thermopile sensor 41 and causes the display device 120 to continuously display the temperature of the rotor 21.

The controller 110 determines whether an average value over a predetermined period of the temperature of the rotor 21, obtained based on the temperature of the shaft 20 acquired from the thermopile sensor 41, is equal to or greater than a predetermined threshold. For example, the controller 110 determines whether the average value over a predetermined period, such as one day or one week, is equal to or greater than a predetermined threshold (e.g., 120° C.) . If the controller 110 determines that the average value is equal to or greater than the predetermined threshold, it causes the display device 120 (an example of a notification device) to display a warning. Note that if it is determined that the average value is equal to or greater than the predetermined threshold, and the vacuum pump system 1 is provided with an audio output such as a speaker, the controller 110 may notify the warning by voice. Furthermore, if it is determined that the average value is equal to or greater than the predetermined threshold, the controller 110 may stop the vacuum pump 100 by controlling the current supplied to the motor 4.

In the present embodiment, by using the thermopile sensor 41, the temperature of the shaft 20 can be continuously measured, and therefore the temperature of the rotor 21 fixed to the shaft 20 can be continuously measured. Furthermore, when measuring the temperature of the plated rotor 21 with a thermopile sensor, the radiant heat may change due to age-related degradation of the plating, which may prevent accurate temperature measurement. However, in the present embodiment, the temperature of the rotor blades 261 is measured by measuring the temperature of the unplated shaft 20, which allows for more accurate temperature measurement.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the invention.

In the above embodiment, the thermopile sensor 41 detects the temperature of the protruding portion 32 of the shaft 20, but it is not limited to the protruding portion 32; it may be the temperature of the shaft main body 31, as long as it is the temperature of the shaft 20.

In the above embodiment, the infrared detection surface 41a of the thermopile sensor 41 is disposed on substantially the same plane as the position of the end face 15a in the direction of the axis A, but it may protrude into the through-hole 44 of the sensor casing 42, or it may be disposed further inside the hole 15b than the end face 15a.

In the above embodiment, the controller 110 determines whether the average value over a predetermined period of the temperature of the rotor 21, obtained based on the temperature of the shaft 20 acquired from the thermopile sensor 41, is equal to or greater than a predetermined threshold. However, the present invention is not limited to this, and it may be determined whether an integrated value over a predetermined period of the temperature of the rotor 21 is equal to or greater than a predetermined threshold. If the integrated value is equal to or greater than the predetermined threshold, the controller 110 may display a warning on the display device 120.

In the above embodiment, the controller 110 determines whether the average value or the integrated value of the temperature of the rotor 21 is equal to or greater than a predetermined threshold. However, without converting to the temperature of the rotor 21, it may determine whether the average value or the integrated value of the temperature of the shaft 20 acquired from the thermopile sensor 41 is equal to or greater than a predetermined threshold, and issue a warning if the average value or the integrated value is equal to or greater than the predetermined threshold.

In the above embodiment, the temperature of the rotor 21 is obtained from the temperature of the detected value using a conversion table. However, the present invention is not limited to this, and if a relational expression between the detected value of the thermopile sensor 41 and the temperature of the rotor 21 can be obtained, the temperature of the rotor 21 may be obtained from the temperature of the detected value using the relational expression.

In the above embodiment, the temperature of the rotor 21 is obtained, but it may be limited to obtaining the temperature of the rotor blade portion 22 or the rotor blades 261 of the rotor 21. In this case, the temperature of the rotor blade portion 22 or the rotor blades 261 may be displayed on the display device 120.

In the above embodiment, the rotor 21 includes the rotor blade portion 22 and the rotor cylindrical portion 23, but the rotor 21 may not be provided with the rotor cylindrical portion 23.

Aspects

A person skilled in the art will understand that the plurality of exemplary embodiments described above are specific examples of the following aspects.

(First Aspect) A vacuum pump comprises a rotor, a shaft, a radial housing, and a radiation temperature sensor. The rotor includes a plurality of rotor blades. The shaft is fixed to the rotor and is not subjected to plating treatment. The radial housing is disposed so as to surround the periphery of the shaft. The radiation temperature sensor is disposed in the radial housing and measures the temperature of the shaft.

In the vacuum pump according to the first aspect, by using a radiation temperature sensor, the temperature of the shaft can be continuously measured. Therefore, the temperature of the rotor blades fixed to the shaft can be continuously measured. Furthermore, when measuring the temperature of rotor blades that have been plated for corrosive gas resistance with a radiation temperature sensor, the radiant heat may change due to age-related degradation of the plating treatment, which may prevent accurate temperature measurement. However, in this aspect, since the temperature of the rotor blades is measured by measuring the temperature of the unplated shaft, accurate temperature measurement can be performed without being affected by age-related degradation.

(Second Aspect) In the vacuum pump according to the first aspect, the shaft includes a shaft main body along a rotation axis, and a protruding portion connected to the rotor on an exhaust upstream side and protruding from the shaft main body in a direction perpendicular to the rotation axis. The protruding portion faces an end face on the exhaust upstream side of the radial housing. The radiation temperature sensor is disposed on the end face and measures the temperature of the protruding portion.

In the vacuum pump according to the second aspect, the radiation temperature sensor is disposed so as to face the protruding portion connected to the rotor on the exhaust upstream side. Since the protruding portion is relatively close to the connection part with the rotor among the entire shaft, the temperature of the protruding portion is relatively close to the temperature of the rotor. Therefore, when the temperature of the protruding portion is measured and the temperature of the rotor is determined thereby, the temperature of the rotor can be determined more accurately.

(Third Aspect) The vacuum pump according to the first aspect further comprises a sensor casing fixed to the radial housing and disposed so as to cover the radiation temperature sensor. The sensor casing is formed with a through-hole extending from the radiation temperature sensor toward the shaft.

In the vacuum pump according to the third aspect, while infrared rays from the shaft pass through the through-hole and are then absorbed by the radiation temperature sensor, the detection of infrared rays by the radiation temperature sensor from components other than the shaft, for example, the plated rotor, is suppressed, so that the temperature of the shaft can be measured more accurately.

(Fourth Aspect) The vacuum pump according to the first aspect further comprises a sensor cover disposed in the through-hole and covering the radiation temperature sensor.

In the vacuum pump according to the fourth aspect, even when a corrosive gas is used as the gas to be evacuated, the provision of the sensor cover can suppress the corrosive gas from coming into contact with the radiation temperature sensor and causing the radiation temperature sensor to be damaged or to malfunction.

(Fifth Aspect) A vacuum pump system comprises the vacuum pump according to any one of the first to fourth aspects, a controller, and a display device. The controller determines the temperature of the rotor based on the temperature of the shaft measured by the radiation temperature sensor. The display device displays the temperature of the rotor.

In the vacuum pump according to the fifth aspect, a user can continuously check the temperature of the rotor. This allows the user to increase the process gas flow rate while checking the temperature of the rotor.

(Sixth Aspect) A vacuum pump system comprises the vacuum pump according to any one of the first to fourth aspects, a controller, and a notification device. The controller determines whether an average value or an integrated value over a predetermined period of the temperature of the shaft measured by the radiation thermometer or the temperature of the rotor obtained based on the shaft temperature is equal to or greater than a predetermined threshold. The notification device issues a warning when it is determined that the average value or the integrated value is equal to or greater than the predetermined threshold.

In the vacuum pump according to the sixth aspect, since a warning can be issued to the user, the user can temporarily increase the process gas flow rate.

REFERENCE SIGNS LIST

• • 1: Vacuum pump system, 2: Housing, 3: Rotating body unit, 4: Motor, 5: Stator blade set, 6: Stator cylindrical portion, 7: Casing, 8: Base, 9: Fixing flange, 11: First end portion, 11a: Intake port, 12: Second end portion, 13: Side surface, 14: Base main body, 15: Radial housing, 15a: End face, 15b: Hole, 16: Base end portion, 17: Bottom surface, 18: Side surface, 18a: Exhaust port, 19: Connector, 20: Shaft, 21: Rotor, 22: Rotor blade portion, 23: Rotor cylindrical portion, 24: Fixing portion, 25: Rotor blade attachment portion, 26: Rotor blade set, 27: Bolt, 28: End portion, 29: End portion, 31: Shaft main body, 32: Protruding portion, 32a: Surface, 33: Convex portion, 34: Protection bearing, 35A-35C: Bearing, 41: Thermopile sensor, 41a: Detection surface, 42: Sensor casing, 43: Sensor cover, 44: Through-hole, 44a: Large-diameter portion, 44b: Small-diameter portion, 44c: Step surface, 51: Stator blade, 100: Vacuum pump, 110: Controller, 120: Display device, 261: Rotor blade, A: Axis, P1: Turbine section, P2: Drag pump section, S1: First internal space, S2: Second internal space