vacuum pump

Abstract

To accurately measure the temperature of the vacuum pump rotor. [Solution] The vacuum pump 1 comprises a rotor 4, a plurality of state change units 6, a sensor 7, and a control device 8. The state change units 6 are arranged on the surface 4A of the rotor 4 and change between a first color and a second color at a predetermined state change temperature. The state change temperature is different for each of the plurality of state change units 6. The sensor 7 detects the first color and / or second color of the plurality of state change units 6. The control device 8 calculates the temperature of the rotor 4 based on the first color and / or second color of the plurality of state change units 6 detected by the sensor 7.

Description

Technical Field

[0007]

[0001] The present invention relates to a vacuum pump.

Background Art

[0002] Some vacuum pumps include a rotor having rotor blades and a rotor cylinder portion and being rotationally driven. In this vacuum pump, the rotor is rotated to suck the inside of the device to be evacuated, and the sucked gas is discharged to the outside.

[0003] In the above vacuum pump, the rotor rotates at high speed and / or the inside is heated to prevent the product from depositing, so the rotor may be heated to a high temperature. If the rotor becomes excessively hot, the components of the vacuum pump may be deformed or the like, which may interfere with the operation of the vacuum pump. For the purpose of checking whether the temperature of the rotor is appropriate, the temperature of the rotor is measured in the above vacuum pump (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As a conventional method for measuring the temperature of a rotor, there is a method using a magnetic material disposed on the surface of the rotor. In this method, it is difficult to accurately measure the temperature of the rotor because it can only be determined whether the temperature of the rotor is higher or lower than the Curie temperature of the magnetic material. <00OO030> Therefore, an object of the present invention is to accurately measure the temperature of the rotor of a vacuum pump.

Means for Solving the Problems

[0007] A vacuum pump according to one aspect of the present invention comprises a rotor, a plurality of state change units, a sensor, and a calculation unit. The rotor is rotationally driven. The state change units are arranged on the surface of the rotor and change between a first color and a second color at a predetermined state change temperature. The state change temperature is different for each of the plurality of state change units. The sensor detects the first color and / or second color of the plurality of state change units. The calculation unit calculates the temperature of the rotor based on the first color and / or second color of the plurality of state change units detected by the sensor. [Effects of the Invention]

[0008] In the vacuum pump described above, multiple phase change zones are arranged on the rotor surface, and the phase change temperature at which the color of each phase change zone changes is different for each of these zones. Because there are multiple phase change zones, multiple color combinations are possible, and because the phase change temperatures differ for each zone, each of these color combinations will have a different temperature range on the rotor. Therefore, by detecting the colors of the multiple phase change zones with sensors and calculating the rotor temperature based on the color combinations detected by the sensors, it becomes possible to measure the rotor temperature over multiple temperature ranges. This ability to measure the rotor temperature over multiple temperature ranges allows for more precise and accurate measurement of the rotor temperature than conventional methods. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view of a vacuum pump. [Figure 2A] This figure shows an example of the arrangement of multiple state-changing parts in a rotor. [Figure 2B] This figure shows another example of the arrangement of multiple state-changing parts in a rotor. [Figure 3A] This figure shows an example of the output pattern of the signal output from the sensor. [Figure 3B] This figure shows another example of the output pattern of the signal output from the sensor. [Modes for carrying out the invention]

[0010] The vacuum pump 1 will be described below using Figure 1. Figure 1 is a cross-sectional view of the vacuum pump 1. The vacuum pump 1 includes a housing 2, a base 3, a rotor 4, and a stator 5.

[0011] The housing 2 includes a first end 11, a second end 12, and a first internal space S1. The first end 11 is provided with an intake port 13. The intake port 13 is connected to the interior of an exhaust device (not shown) in a gas-flowable manner. The first internal space S1 is in communication with the intake port 13. The second end 12 is located opposite the first end 11 in the axial direction of the rotor 4 (hereinafter simply referred to as "axial direction A1"). The second end 12 is connected to the base 3. The base 3 includes a base end 14. The base end 14 is connected to the second end 12 of the housing 2.

[0012] The rotor 4 is housed in the internal space of the housing 2. The rotor 4 is attached to one end of the shaft 21. The shaft 21 extends in the axial direction A1. The shaft 21 is rotatably housed in the base 3. That is, the rotor 4 rotates due to the rotation of the shaft 21. A thrust disc 21A is provided at the lower part of the shaft 21. Furthermore, a target 21B is screwed to the lower end of the shaft 21.

[0013] The rotor 4 includes multiple stages of rotor blades 22 and a rotor cylindrical section 23. Each of the multiple stages of rotor blades 22 is connected to the shaft 21 at an angle with respect to the axial direction A1. The multiple stages of rotor blades 22 are spaced apart from each other in the axial direction A1. Although not shown in the figure, each of the multiple stages of rotor blades 22 extends radially from the shaft 21. In the figure, only one of the multiple stages of rotor blades 22 is labeled, and the labels of the other rotor blades 22 are omitted. The rotor cylindrical section 23 is located below the multiple stages of rotor blades 22. The rotor cylindrical section 23 extends in the axial direction A1.

[0014] The stator 5 is located on the outer circumference of the rotor 4. The stator 5 includes multiple stages of stator blades 31 and a stator cylindrical section 32. Each of the multiple stages of stator blades 31 is inclined in the opposite direction to the inclination of the rotor blades 22 and connected to the inner surface of the housing 2. For example, if the rotor blades 22 are inclined from the intake side to the exhaust side, the stator blades 31 are inclined from the exhaust side to the intake side. On the other hand, if the rotor blades 22 are inclined from the exhaust side to the intake side, the stator blades 31 are inclined from the intake side to the exhaust side. The inclination direction of the rotor blades 22 and stator blades 31 can be appropriately determined by the rotation direction of the rotor 4, etc.

[0015] The multiple stages of stator blades 31 are spaced apart from each other in the axial direction A1. Each of the multiple stages of stator blades 31 is positioned between each of the multiple stages of rotor blades 22. Although not shown in the figure, each of the multiple stages of stator blades 31 extends radially from the shaft 21. In the drawing, only two of the multiple stages of stator blades 31 are labeled with reference numerals, and the reference numerals for the other stator blades 31 are omitted. The stator cylindrical portion 32 is fixed in contact with the base 3. The stator cylindrical portion 32 is positioned facing the outer circumferential surface of the rotor cylindrical portion 23 in the radial direction of the rotor cylindrical portion 23, with a small gap between them. A helical groove is provided on the inner circumferential surface of the stator cylindrical portion 32 facing the rotor cylindrical portion 23.

[0016] As shown in Figure 1, an exhaust space S2 is formed downstream of the exhaust-downstream ends of the rotor cylindrical section 23 and the stator cylindrical section 32. The exhaust gas discharged from the device to be exhausted is guided into the exhaust space S2. The exhaust space S2 is in communication with an exhaust port 15. The exhaust port 15 is provided on the base 3. Another vacuum pump (not shown) is connected to the exhaust port 15. The exhaust-downstream side refers to the side closer to the exhaust space S2 in the axial direction A1. The exhaust-downstream direction refers to the direction toward the exhaust space S2.

[0017] The vacuum pump 1 includes bearings 41A and 41E, magnetic bearings 41B to 41D, and a motor 42. The bearings 41A and 41E are attached to positions that house the shaft 21 of the base 3. The bearings 41A and 41E rotatably support the shaft 21. The bearings 41A and 41E are ball bearings. The magnetic bearings 41B to 41D are bearings that support the shaft 21 by magnetic force. Among these, the magnetic bearings 41B and 41C are radial magnetic bearings that support the shaft 21 in the radial direction. The magnetic bearing 41D is a thrust magnetic bearing that supports the shaft 21 in the axial direction.

[0018] The motor 42 rotationally drives the rotor 4 by rotationally driving the shaft 21. The motor 42 includes a motor rotor 42A and a motor stator 42B. The motor rotor 42A is attached to the shaft 21. The motor stator 42B is attached to the base 3. The motor stator 42B is arranged facing the motor rotor 42A.

[0019] On the outer wall of the base 3, a heater 71 for controlling the temperature of the base 3 and a cooling water pipe are provided. The temperature of the base 3 is controlled by the balance between heating of the base 3 by the heater 71 and cooling by the cooling water flowing through the cooling water pipe. By controlling the temperature of the base 3, the temperature of the rotor 4 is also adjusted by heat transfer from the rotor 4 to the base 3 or from the base 3 to the rotor 4.

[0020] In the vacuum pump 1, the plurality of stages of rotor blades 22 and the plurality of stages of stator blades 31 constitute a turbomolecular pump section. Also, the rotor cylinder section 23 and the stator cylinder section 32 constitute a screw groove pump section. In the vacuum pump 1, when the rotor 4 rotates by the motor 42, the exhaust target gas flows into the first internal space S1 from the inside of the device to be discarded through the intake port 13. The exhaust target gas in the first internal space S1 passes through the turbomolecular pump section and the screw groove pump section and is guided to the exhaust space S2. The exhaust target gas in the exhaust space S2 is exhausted from the exhaust port 15. As a result, the inside of the device to be discarded attached to the intake port 13 becomes a high-vacuum state.

[0021] The vacuum pump 1 includes a state change unit 6, a sensor 7, and a control device 8. The state change unit 6 is composed of a substance whose state changes with a predetermined temperature (referred to as the state change temperature) as a boundary. The state change unit 6 is, for example, a member whose state changes between a first state and a second state with the state change temperature as a boundary. As such a state change unit 6, for example, there is a reversible thermo label (registered trademark). The state change unit 6 which is a thermo label (registered trademark) changes between a first color and a second color with the state change temperature as a boundary. Specifically, the state change unit 6 which is a thermo label (registered trademark) becomes the first color (for example, white, etc.) when its temperature is below the state change temperature, and becomes the second color (for example, black, etc.) when it is higher than the state change temperature.

[0022] The state change unit 6 which is a thermo label (registered trademark) can be easily arranged on the rotor 4 by opposing the surface where the state changes due to temperature to the upper end 3A of the base 3, and attaching the opposite surface to the surface 4A of the rotor 4.

[0023] As shown in FIG. 1, FIG. 2A, and FIG. 2B, a plurality of state change units 6 are arranged along the rotation direction of the rotor 4 (the direction indicated by the arrows in FIG. 2A and FIG. 2B) on the surface 4A of the rotor 4 facing the upper end 3A of the base 3. For example, in the order in which the state is detected by the sensor 7 when the rotor 4 rotates, six state change units such as the first state change unit 6a, the second state change unit 6b, the third state change unit 6c, the fourth state change unit 6d, the fifth state change unit 6e, and the sixth state change unit 6f are arranged.

[0024] The plurality of state change units can be arranged along the rotation direction of the rotor 4 with a predetermined interval on the surface 4A of the rotor 4 as shown in FIG. 2A. In addition, the plurality of state change units can be arranged along the rotation direction of the rotor 4 packed without an interval on the surface 4A of the rotor 4 as shown in FIG. 2B. FIG. 2A is a diagram showing an example of the arrangement state of the plurality of state change units on the rotor 4. FIG. 2B is a diagram showing another example of the arrangement state of the plurality of state change units on the rotor 4. Note that FIG. 2A and FIG. 2B are views of the inside of the rotor 4 seen from below.

[0025] In the examples shown in Figures 2A and 2B, the number of state-changing units on the rotor 4 is set to 6. However, the number of state-changing units on the rotor 4 is not limited to this and can be any number depending on the temperature range to be measured, etc.

[0026] Each of the multiple state-changing sections has a different state-changing temperature. As a result, in the vacuum pump 1, the combination of state-changing sections in the first state and those in the second state differs depending on the temperature of the rotor 4. In this embodiment, the temperature of the rotor 4 is measured by utilizing the fact that the combination of states of the multiple state-changing sections differs depending on the temperature of the rotor 4. The specific method for measuring the temperature of the rotor 4 will be explained later.

[0027] Sensor 7 is positioned so that one end of it faces the state change unit 6 located on the rotor 4 at the upper end 3A of the base 3. This end of sensor 7 is called the "detection end" because it is the end that detects the state of the state change unit 6. This detection end of sensor 7 is connected to wiring such as optical fiber or electric wire, and this wiring connects to the connection port 9. The control device 8 is connected to the connection port 9. The wiring of sensor 7 is housed in a space in the base 3 that is pre-provided to accommodate other wiring and lead to the connection port 9, and is then led to the connection port 9.

[0028] If the state change unit 6 changes between a first color and a second color at a state change temperature such as a thermolabel (registered trademark), then the sensor 7 is, for example, a fiber sensor capable of detecting the first color and / or the second color. Specifically, the sensor 7, which is a fiber sensor, irradiates a predetermined light from its detection end, receives the reflected light that has been reflected by the state change unit 6 and returned to the detection end, and outputs a signal based on the intensity of the received reflected light.

[0029] For example, if the sensor 7 outputs a signal with a first signal value when it detects a first color and a signal with a second signal value when it detects a second color, and if the multiple state change units 6 are arranged at predetermined intervals as shown in Figure 2A, then during one rotation of the rotor 4, the sensor 7 outputs a number of first pulse signals having a first signal value corresponding to the number of state change units 6 that are the first color, and / or a number of second pulse signals having a second signal value corresponding to the number of state change units 6 that are the second color.

[0030] On the other hand, when multiple state-changing units 6 are arranged closely together as shown in Figure 2B, during one rotation of the rotor 4, the sensor 7 outputs a signal with a first signal value for a duration corresponding to the number of state-changing units 6 of the first color, and / or outputs a signal with a second signal value for a duration corresponding to the number of state-changing units 6 of the second color. The duration of the signal with the first signal value can also be seen as corresponding to the number of first pulse signals, and the duration of the signal with the second signal value can be seen as corresponding to the number of second pulse signals.

[0031] The control device 8 is a computer system composed of arithmetic circuits such as a CPU, memory devices (such as RAM, ROM, HDD, and SSD), and various interfaces, and performs various information processing related to the vacuum pump 1. The control device 8 controls the rotation of the rotor 4 by controlling the rotation of the motor 42. The control device 8 supports the shaft 21 by controlling the magnetic bearings 41B to 41D.

[0032] The control device 8 calculates the temperature of the rotor 4 based on the signal output from the sensor 7. The control device 8 may, if necessary, control the heater 71 based on the calculated temperature of the rotor 4.

[0033] The following describes a method for calculating the temperature of the rotor 4 using the state change unit 6. This calculation method is performed by the control device 8. The control device 8 may perform the method for calculating the temperature of the rotor 4 described below by executing a program stored in the memory device. Alternatively, part or all of the method for calculating the temperature of the rotor 4 may be implemented by the hardware constituting the control device 8.

[0034] In the following description, as shown in Figures 2A and 2B, it is assumed that six state-changing sections are arranged in the order in which the state is detected by the sensor 7 when the rotor 4 rotates: the first state-changing section 6a, the second state-changing section 6b, the third state-changing section 6c, the fourth state-changing section 6d, the fifth state-changing section 6e, and the sixth state-changing section 6f. These state-changing sections appear white at temperatures below the state-changing temperature and appear black at temperatures above the state-changing temperature. When the sensor 7 detects a black state-changing section, it outputs a signal with a second signal value that is not zero (a second pulse signal). When it detects a white state-changing section, it either does not output a signal or outputs a signal with a signal value that is sufficiently smaller than the second signal value (i.e., the first signal value ≈ 0).

[0035] Furthermore, each of the multiple state change sections has a state change temperature that increases in the order in which the state is detected by the sensor 7 when the rotor 4 rotates. Specifically, the state change temperature of the first state change section 6a is set to the first temperature T1, the state change temperature of the second state change section 6b is set to the second temperature T2 which is greater than the first temperature T1, the state change temperature of the third state change section 6c is set to the third temperature T3 which is greater than the second temperature T2, the state change temperature of the fourth state change section 6d is set to the fourth temperature T4 which is greater than the third temperature T3, the state change temperature of the fifth state change section 6e is set to the fifth temperature T5 which is greater than the fourth temperature T4, and the state change temperature of the sixth state change section 6f is set to the sixth temperature T6 which is greater than the fifth temperature T5. In other words, the state change temperature of the first state change section 6a (first temperature T1) < the state change temperature of the second state change section 6b (second temperature T2) < the state change temperature of the third state change section 6c (third temperature T3) < the state change temperature of the fourth state change section 6d (fourth temperature T4) < the state change temperature of the fifth state change section 6e (fifth temperature T5) < the state change temperature of the sixth state change section 6f (sixth temperature T6).

[0036] In the above case, when a plurality of state change portions are arranged at intervals as shown in FIG. 2A, while the rotor 4 makes one rotation, from the sensor 7, a signal of a pattern as shown in FIG. 3A is output. That is, while the rotor 4 makes one rotation, a second pulse signal having 0 to 6 second signal values (S2 in FIG. 3A) is output from the sensor 7. FIG. 3A is a diagram showing an example of an output pattern of a signal output from the sensor 7.

[0037] As shown in FIG. 3A, when three second pulse signals are obtained while the rotor 4 makes one rotation when the temperature of the rotor 4 is T, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the third temperature T3 and less than or equal to the fourth temperature (that is, T3 < T ≤ T4).

[0038] Specifically, that the temperature T is greater than the third temperature T3 (the state change temperature of the third state change portion 6c) also means that the temperature T is greater than the first temperature T1 (the state change temperature of the first state change portion 6a) and greater than the second temperature T2 (the state change temperature of the second state change portion 6b). Therefore, the first state change portion 6a to the third state change portion 6c become black. On the other hand, that the temperature T is less than or equal to the fourth temperature T4 (the state change temperature of the fourth state change portion 6d) also means that the temperature T is less than the fifth temperature T5 (the state change temperature of the fifth state change portion 6e) and less than the sixth temperature T6 (the state change temperature of the sixth state change portion 6f). Therefore, the fourth state change portion 6d to the sixth state change portion 6f become white. As a result of the above, when the temperature of the rotor 4 is the above temperature T, while the rotor 4 makes one rotation, three black first state change portions 6a to 6c are detected by the sensor 7, and three second pulse signals are output from the sensor 7.

[0039] Based on the above, when no second pulse signal is obtained during one rotation of the rotor 4 (the number of second pulse signals: 0), the control device 8 can calculate that the temperature T of the rotor 4 is equal to or lower than the first temperature T1 (i.e., T≦T1). When one second pulse signal is obtained during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the first temperature T1 and equal to or lower than the second temperature T2 (i.e., T1<T≦T2). When two second pulse signals are obtained during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the second temperature T2 and equal to or lower than the third temperature (i.e., T2<T≦T3).

[0040] When four second pulse signals are obtained during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the fourth temperature T4 and equal to or lower than the fifth temperature T5 (i.e., T4<T≦T5). When five second pulse signals are obtained during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the fifth temperature T5 and equal to or lower than the sixth temperature T6 (i.e., T5<T≦T6). When six second pulse signals are obtained during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the sixth temperature T6 (i.e., T6<T).

[0041] In addition, when the sensor 7 outputs a signal (first pulse signal) with a non-zero first signal value when detecting a white state change part, and does not output a signal or outputs a signal with a signal value sufficiently smaller than the first signal value (i.e., second signal value ≈ 0) when detecting a black state change part, the relationship between the temperature of the rotor 4 and the number of output pulses is as follows.

[0042] That is, when six first pulse signals are obtained while the rotor 4 makes one rotation, the temperature T of the rotor 4 can be calculated to be not higher than the first temperature T1 (i.e., T≤T1). When five first pulse signals are obtained while the rotor 4 makes one rotation, the temperature T of the rotor 4 can be calculated to be greater than the first temperature T1 and not higher than the second temperature T2 (i.e., T1<T≤T2). When four second pulse signals are obtained while the rotor 4 makes one rotation, the temperature T of the rotor 4 can be calculated to be greater than the second temperature T2 and not higher than the third temperature T3 (i.e., T2<T≤T3). When three first pulse signals are obtained while the rotor 4 makes one rotation, the temperature T of the rotor 4 can be calculated to be greater than the third temperature T3 and not higher than the fourth temperature T4 (i.e., T3<T≤T4).

[0043] When two first pulse signals are obtained while the rotor 4 makes one rotation, the temperature T of the rotor 4 can be calculated to be greater than the fourth temperature T4 and not higher than the fifth temperature T5 (i.e., T4<T≤T5). When one first pulse signal is obtained while the rotor 4 makes one rotation, the temperature T of the rotor 4 can be calculated to be greater than the fifth temperature T5 and not higher than the sixth temperature T6 (i.e., T5<T≤T6). When no first pulse signal is obtained while the rotor 4 makes one rotation (the number of first pulse signals: 0), the temperature T of the rotor 4 can be calculated to be greater than the sixth temperature T6 (i.e., T6<T).

[0044] The relationship between the temperature of the rotor 4 and the number of output pulses described above is the same even when the relationship of the state change temperature is opposite to the above, that is, when the state change temperature of the first state change part 6a (the first temperature T1)>the state change temperature of the second state change part 6b (the second temperature T2)>the state change temperature of the third state change part 6c (the third temperature T3)>the state change temperature of the fourth state change part 6d (the fourth temperature T4)>the state change temperature of the fifth state change part 6e (the fifth temperature T5)>the state change temperature of the sixth state change part 6f (the sixth temperature T6).

[0045] Even when the plurality of state change portions are not arranged in the order of the state change temperatures, the output pattern (output timing) of the pulse signal is different, but the relationship between the temperature of the rotor 4 and the number of pulses output is the same as described above. Further, although the pulse width of the second pulse signal changes according to the rotational speed of the rotor 4, the relationship between the temperature of the rotor 4 and the number of pulses output does not depend on the rotational speed of the rotor 4. Also, even when the discoloration pattern between white and black due to the temperature of the state change portion 6 is opposite to the above, the temperature of the rotor 4 can be calculated in the same manner.

[0046] Thus, as shown in FIG. 2A, by arranging a plurality of state change portions at intervals in the rotor 4 and calculating the temperature of the rotor 4 based on the number of pulses output from the sensor 7, the temperature of the rotor 4 can be accurately calculated without being affected by the arrangement state (arrangement pattern) of the plurality of state change portions and the rotational speed of the rotor 4.

[0047] On the other hand, as shown in FIG. 2B, when the plurality of state change portions are arranged closely together, while the rotor 4 makes one rotation, a signal having a pattern as shown in FIG. 3B is output from the sensor 7. That is, while the rotor 4 makes one rotation, a signal having a second signal value (S2 in FIG. 3B) with a time length corresponding to the number of black or white state change portions is output from the sensor 7. FIG. 3B is a diagram showing another example of the output pattern of the signal output from the sensor 7.

[0048] As shown in FIG. 3B, when a signal having a second signal value with a length of t1 + t2 + t3 is obtained while the rotor 4 makes one rotation when the temperature of the rotor 4 is T, the control device 8 can calculate the temperature T of the rotor 4 to be greater than the third temperature T3 and less than or equal to the fourth temperature (that is, T3 < T ≦ T4). The time t1 is the time length for detecting the black first state change portion 6a by the sensor 7, the time t2 is the time length for detecting the black second state change portion 6b by the sensor 7, and the time t3 is the time length for detecting the black second state change portion 6b by the sensor 7.

[0049] Specifically, if temperature T is greater than the third temperature T3 (the phase change temperature of the third phase change section 6c), it also means that temperature T is greater than the first temperature T1 (the phase change temperature of the first phase change section 6a) and also greater than the second temperature T2 (the phase change temperature of the second phase change section 6b). Therefore, the first phase change sections 6a to the third phase change sections 6c will be black. On the other hand, if temperature T is less than or equal to the fourth temperature T4 (the phase change temperature of the fourth phase change section 6d), it also means that temperature T is less than the fifth temperature T5 (the phase change temperature of the fifth phase change section 6e) and also less than the sixth temperature T6 (the phase change temperature of the sixth phase change section 6f). Therefore, the fourth phase change sections 6d to the sixth phase change sections 6f will be white. As a result of the above, when the temperature of the rotor 4 is the above temperature T, the sensor 7 detects a signal with a time duration t1 by detecting the black first state change part 6a, a signal with a time duration t2 by detecting the black second state change part 6b, and a signal with a time duration t3 by detecting the black third state change part 6c during one rotation of the rotor 4. As a result, the sensor 7 outputs a signal with a second signal value having a total time duration of t1 + t2 + t3.

[0050] The above time t1 can be calculated as L1 / V, where L1 is the length of the first state change section 6a and V is the rotational speed of the rotor 4. The time t2 can be calculated as L2 / V, where L2 is the length of the second state change section 6b and V is the rotational speed of the rotor 4. The time t3 can be calculated as L1 / V, where L3 is the length of the third state change section 6c and V is the rotational speed of the rotor 4.

[0051] Similarly, the time duration (let's call it time t4) for the sensor 7 to detect the black fourth state change section 6d can be calculated as L4 / V, where L4 is the length of the fourth state change section 6d and V is the rotational speed of the rotor 4. The time duration (let's call it time t5) for the sensor 7 to detect the black fifth state change section 6e can be calculated as L5 / V, where L5 is the length of the fifth state change section 6e and V is the rotational speed of the rotor 4. The time duration (let's call it time t6) for the sensor 7 to detect the black sixth state change section 6f can be calculated as L6 / V, where L4 is the length of the sixth state change section 6f and V is the rotational speed of the rotor 4.

[0052] Based on the above, when no signal with a second signal value is output during one rotation of the rotor 4 (signal output time length: 0), the control device 8 can calculate that the temperature T of the rotor 4 is not more than the first temperature T1 (i.e., T ≤ T1). When a signal with a time length of t1 is output during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the first temperature T1 and not more than the second temperature T2 (i.e., T1 < T ≤ T2). When a signal with a time length of t1 + t2 is output during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the second temperature T2 and not more than the third temperature (i.e., T2 < T ≤ T3).

[0053] When a signal with a time length of t1 + t2 + t3 + t4 is output during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the fourth temperature T4 and not more than the fifth temperature T5 (i.e., T4 < T ≤ T5). When a signal with a time length of t1 + t2 + t3 + t4 + t5 is output during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the fifth temperature T5 and not more than the sixth temperature T6 (i.e., T5 < T ≤ T6). When a signal with a time length of t1 + t2 + t3 + t4 + t5 + t6 is output during one rotation of the rotor 4, the control device 8 can calculate that the temperature T of the rotor 4 is greater than the sixth temperature T6 (i.e., T6 < T).

[0054] In addition, when the sensor 7 outputs a signal (first pulse signal) with a first signal value that is not 0 when detecting a white state change part, and does not output a signal or outputs a signal with a signal value sufficiently smaller than the first signal value (i.e., second signal value ≈ 0) when detecting a black state change part, the relationship between the temperature of the rotor 4 and the number of pulses output is as follows.

[0055] That is, when a signal with a time length of t1 + t2 + t3 + t4 + t5 + t6 having a first signal value is output during one rotation of the rotor 4, the temperature T of the rotor 4 can be calculated to be not higher than the first temperature T1 (i.e., T ≤ T1). When a signal with a time length of t2 + t3 + t4 + t5 + t6 is output during one rotation of the rotor 4, the temperature T of the rotor 4 can be calculated to be greater than the first temperature T1 and not higher than the second temperature T2 (i.e., T1 < T ≤ T2). When a signal with a time length of t3 + t4 + t5 + t6 is output during one rotation of the rotor 4, the temperature T of the rotor 4 can be calculated to be greater than the second temperature T2 and not higher than the third temperature T3 (i.e., T2 < T ≤ T3). When a signal with a time length of t4 + t5 + t6 is output during one rotation of the rotor 4, the temperature T of the rotor 4 can be calculated to be greater than the third temperature T3 and not higher than the fourth temperature T4 (i.e., T3 < T ≤ T4).

[0056] When a signal with a time length of t5 + t6 is output during one rotation of the rotor 4, the temperature T of the rotor 4 can be calculated to be greater than the fourth temperature T4 and not higher than the fifth temperature T5 (i.e., T4 < T ≤ T5). When a signal with a time length of t6 is output during one rotation of the rotor 4, the temperature T of the rotor 4 can be calculated to be greater than the fifth temperature T5 and not higher than the sixth temperature T6 (i.e., T5 < T ≤ T6). When no signal is output during one rotation of the rotor 4 (signal output time length: 0), the temperature T of the rotor 4 can be calculated to be greater than the sixth temperature T6 (i.e., T6 < T).

[0057] The relationship between the temperature of rotor 4 and the duration for which the signal is output, as described above, is the same even when the relationship of state change temperatures is reversed, i.e., state change temperature of the first state change unit 6a (first temperature T1) > state change temperature of the second state change unit 6b (second temperature T2) > state change temperature of the third state change unit 6c (third temperature T3) > state change temperature of the fourth state change unit 6d (fourth temperature T4) > state change temperature of the fifth state change unit 6e (fifth temperature T5) > state change temperature of the sixth state change unit 6f (sixth temperature T6). Furthermore, the same applies even when the signal is output as multiple signals rather than a single continuous signal, and the multiple state change units are not arranged in order of state change temperature.

[0058] Furthermore, the rotational speed of the rotor 4 is monitored by the control device 8, and the length of each state change section is predetermined. Therefore, the temperature of the rotor 4 can be calculated based on the duration of the signal output as described above. Moreover, even if the white and black color change patterns of the state change section 6 are reversed from those described above, the temperature of the rotor 4 can be calculated in the same manner.

[0059] As shown in Figure 2B, by arranging multiple state-changing units closely spaced on the rotor 4 and calculating the temperature of the rotor 4 based on the duration of the signal output from the sensor 7, the temperature of the rotor 4 can be accurately calculated without being affected by the arrangement (arrangement pattern) of the multiple state-changing units.

[0060] Furthermore, even when multiple state-changing units are spaced apart on the rotor 4, as shown in Figure 2A, the temperature of the rotor 4 can be calculated based on the duration of the signal output from the sensor 7. Also, even when multiple state-changing units are spaced close together on the rotor 4, as shown in Figure 2B, the temperature of the rotor 4 can be calculated based on the number of pulse signals output from the sensor 7. This is because there is a correspondence between the number of pulse signals and the duration of the signals.

[0061] As described above, in the vacuum pump 1, multiple state change sections (first state change section 6a to sixth state change section 6f) are arranged on the surface 4A of the rotor 4, and the state change temperature at which the state of the state change section 6 changes is different for each of the multiple state change sections. Because there are multiple state change sections, multiple combinations of states of the state change sections are possible, and because the state change temperature is different for each of the multiple state change sections, as explained above, each of the multiple state combinations will be different within the temperature range of the rotor 4. Therefore, by detecting the states of the multiple state change sections with the sensor 7 and calculating the temperature of the rotor 4 based on the combination of states detected by the sensor 7, it becomes possible to measure multiple temperature ranges of the rotor 4. By being able to measure multiple temperature ranges of the rotor 4, the temperature of the rotor 4 can be measured more precisely and accurately than before.

[0062] Furthermore, by using a state-changing unit 6 such as a Thermolabel (registered trademark) and a sensor 7 such as a fiber sensor, the temperature measurement configuration for the rotor 4, consisting of the state-changing unit 6 and the sensor 7, can be arranged in a narrow space such as the surface 4A of the rotor 4 and the upper end 3A of the base 3. Moreover, by using a state-changing unit 6 such as a Thermolabel (registered trademark) and a sensor 7 such as a fiber sensor, direct processing of the rotor 4 (for example, blackening the surface 4A of the rotor 4 by applying blackbody paint, etc.) and consideration of the effect of changes in the emissivity of the rotor 4 itself can be eliminated, thus enabling the construction of a temperature measurement configuration for the rotor 4 at low cost.

[0063] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention.

[0064] The state change section 6 may be a component made of a magnetic material whose magnetism changes at the Curie temperature (state change temperature). In this case, the sensor 7 will have a sensor at its detection end that can detect the presence or absence of magnetism in the state change section 6. As a sensor that can detect the presence or absence of magnetism in the state change section 6, for example, a sensor that can detect the magnetic field generated from the state change section 6, such as a Hall sensor, can be used. With this configuration as well, the temperature of the rotor 4 can be calculated in the same way as described above, based on the combination of the presence or absence of magnetism in multiple state change sections.

[0065] In the above embodiment, each of the multiple state-changing parts was configured as an individual component. However, the invention is not limited to this, and for example, multiple state-changing parts can also be realized by arranging multiple materials on a single plate-shaped component, each having a different state-changing temperature at which its state changes.

[0066] The state change unit 6 may have multiple state change temperatures. That is, the state change unit 6 may be capable of taking on three or more states depending on its temperature. If these three or more states can be detected as clearly different signals by the sensor 7, the temperature of the rotor 4 can be accurately measured even when using a state change unit 6 with multiple state change temperatures.

[0067] The states that the state change unit 6 can take are not limited to two extreme states such as white and black, or presence or absence of magnetism. If the sensor 7 can detect them as different signals, the state change unit 6 can take on multiple states in which a certain degree of difference can be recognized, such as red and green, with the state change temperature as the boundary.

[0068] When such a state change unit 6 is used, both the signal with a first signal value (first pulse signal) and the signal with a second signal value (second pulse signal) output from the sensor 7 can be recognized as detection signals. In such cases, the control device 8 can precisely calculate the temperature of the rotor 4 based only on the output pattern of the signal with the first signal value, only on the output pattern of the signal with the second signal value, or on a combination of the output pattern of the signal with the first signal value and the output pattern of the signal with the second signal value (for example, a combination of the number of outputs of the first pulse signal and the number of outputs of the second pulse signal).

[0069] The method for measuring the temperature of the rotor 4 using the state change unit 6 described above can be used for both vacuum pumps composed solely of a turbomolecular pump unit and vacuum pumps composed solely of a screw groove pump unit.

[0070] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0071] (First Embodiment) A vacuum pump (e.g., vacuum pump 1) comprises a rotor (e.g., rotor 4), a plurality of state change units (e.g., state change unit 6, first state change unit 6a to sixth state change unit 6f), a sensor (e.g., sensor 7), and a calculation unit (e.g., control device 8). The rotor is rotationally driven. The state change units are arranged on the surface of the rotor (e.g., surface 4A) and change between a first color and a second color at a predetermined state change temperature. The state change temperature is different for each of the plurality of state change units. The sensor detects the first color and / or second color of the plurality of state change units. The calculation unit calculates the temperature of the rotor based on the first color and / or second color of the plurality of state change units detected by the sensor.

[0072] In the vacuum pump according to the first embodiment, multiple state change zones are arranged on the surface of the rotor, and the state change temperature at which the color of each state change zone changes is different for each of the multiple state change zones. Because there are multiple state change zones, multiple color combinations are possible, and because the state change temperatures are different for each of the multiple state change zones, each of the multiple color combinations will be different within the rotor's temperature range. Therefore, by detecting the colors of the multiple state change zones with a sensor and calculating the rotor temperature based on the color combinations detected by the sensor, it becomes possible to measure multiple temperature ranges of the rotor. By being able to measure multiple temperature ranges of the rotor, the rotor temperature can be measured more precisely and accurately than in conventional methods.

[0073] (Second Embodiment) In the vacuum pump of the first embodiment, the sensor may output a signal having a first signal value when the state change unit is of a first color, and output a signal having a second signal value when the state change unit is of a second color. In the vacuum pump of the second embodiment, the temperature of the rotor can be accurately calculated based on the output pattern of the signal having a first signal value and the signal having a second signal value output from the sensor.

[0074] (Third Embodiment) In the vacuum pump according to the second embodiment, the calculation unit may calculate the rotor temperature based on the number of first pulse signals having a first signal value output from the sensor and / or the number of second pulse signals having a second signal value output from the sensor during one rotation of the rotor. In the vacuum pump according to the third embodiment, the rotor temperature can be accurately calculated without being affected by the arrangement of the multiple state change units, the rotation speed of the rotor, etc.

[0075] (Fourth Embodiment) In the vacuum pump according to the second or third embodiment, the calculation unit may calculate the rotor temperature based on the time during which a signal having a first signal value is output from the sensor and / or the time during which a signal having a second signal value is output from the sensor while the rotor is rotating once. In the vacuum pump according to the fourth embodiment, the rotor temperature can be accurately calculated without being affected by the arrangement of multiple state change units. [Explanation of symbols]

[0076] 1: Vacuum pump 2: Housing 3: Bass 3A: Upper end 4: Rotor 4A: Surface 5: Status 6: State change section 6a: First state change unit 6b: Second state change section 6c: Third state change section 6d: Fourth state change section 6e: Fifth state change section 6f: Sixth state change section 7: Sensor 8: Control device 9: Connection port 11: First end 12:Second end 13: Air intake 14: Base end 15: Exhaust vent 21: Shaft 21A: Thrust Disc 21B: Target 22: Rotor blades 23: Rotor cylindrical section 31: Stator Wing 32: Stator cylindrical section 41A: Bearing 41B: Magnetic bearing 41C: Magnetic bearing 41D: Magnetic bearing 41E: Bearing 42: Motor 42A: Motor Rotor 42B: Motor stator 71: Heater S1: 1st internal space S2: Exhaust space

Claims

1. A rotor that is driven to rotate, The rotor surface is arranged with a plurality of state-changing parts that change between a first color and a second color at a predetermined state-changing temperature, A sensor that detects the first and / or second colors of multiple state-changing sections, A calculation unit that calculates the temperature of the rotor based on the first and / or second colors of a plurality of state change units detected by the sensor, Equipped with, The aforementioned state change temperature is different in each of the multiple state change sections. Vacuum pump.

2. The vacuum pump according to claim 1, wherein the sensor outputs a signal having a first signal value when the state change unit is of the first color, and outputs a signal having a second signal value when the state change unit is of the second color.

3. The vacuum pump according to claim 2, wherein the calculation unit calculates the temperature of the rotor based on the number of first pulse signals having the first signal value output from the sensor and / or the number of second pulse signals having the second signal value output from the sensor during one rotation of the rotor.

4. The vacuum pump according to claim 2, wherein the calculation unit calculates the temperature of the rotor based on the time during which the sensor outputs a signal having the first signal value and / or the time during which the sensor outputs a signal having the second signal value.

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