Vibration sensor unit, rotary electric machine, and pump device

Abstract

Provided are a vibration sensor unit, a rotary electric machine, and a pump device, which can be used in a wide temperature range and which hardly cause failure due to vibration.　A vibration sensor unit 5 according to the present invention has: a conductive wire 7 provided with at least one coil section 70 wound in a circular coil shape; a body 6 which is made of a magnetic material, and is disposed inside the coil section and in contact with the coil section; a power supply 81 which feeds a constant current to the coil section; and a vibration detection section 821 which detects vibration, on the basis of a change in an alternative current component of a voltage generated in the conductive wire. A rotary shaft is provided with a cylindrical outer circumferential surface 322. The body has an annular shape which extends along the circumferential direction of the coil section and through which the rotary shaft can be inserted, or a shape in which a portion of the annular shape is cut out. When the rotary shaft is disposed inside the body so as to rotate in the circumferential direction of the coil section, a part of the rotary shaft disposed inside the body is formed of a material having conductivity or magnetism, and an inner circumferential surface 61 of the body is disposed apart from the outer circumferential surface of the rotary shaft.

Description

Vibration sensor unit, rotating electrical machine, and pump device

[0001] The present invention relates to a vibration sensor unit, a rotating electrical machine, and a pump device.

[0002] When a pump device is used for a long period of time, the bearings supporting the rotating shaft of the motor (rotating electric machine) included in the pump device wear out, causing the rotating shaft to vibrate, and this vibration can lead to a malfunction of the pump device. Therefore, it is necessary to monitor the wear state of the bearings in the pump device. In pump devices that are easy to disassemble and inspect, the wear state of the bearings can be monitored through regular maintenance. However, in pump devices that are not easy to disassemble and inspect (e.g., canned motor pumps, immersion-type wet motor pumps, submerged pumps, etc.), the wear state of the bearings is monitored using an automatic monitoring device or a vibration sensor (see, for example, Patent Document 1).

[0003] JP 2017-53837 A

[0004] The vibration sensor disclosed in Patent Document 1 is a piezoelectric sensor that is attached to a housing of the pump device at a position parallel to the rotation axis so as to detect acceleration in a direction perpendicular to the rotation axis.

[0005] Some pump devices pump high-temperature liquids (e.g., oil) or cryogenic liquids (e.g., liquefied gas). In such pump devices, not only the vibration sensor but also the signal wires and connectors are exposed to the special temperature environment. Because ordinary vibration sensors cannot withstand the special temperature environment, dedicated vibration sensors are used for such pump devices. However, dedicated vibration sensors are expensive and cannot be used in temperature environments beyond their temperature compensation range. Furthermore, due to the structure of the vibration sensor, vibrations must be transmitted to the sensing unit itself, which detects the vibrations of the rotating shaft. As a result, unintended vibrations (other than those of the rotating shaft) may also be detected, resulting in false detections. Furthermore, the sensing unit is prone to malfunction due to vibrations.

[0006] An object of the present invention is to provide a vibration sensor unit, a rotating electrical machine, and a pump device that can be used over a wide temperature range and are less susceptible to failure due to vibration.

[0007] In one embodiment of the present invention, a vibration sensor unit is a vibration sensor unit that detects vibrations of a rotating shaft of a rotating electric machine, and comprises: a conductor having at least one coil portion wound into a circular coil shape; a main body portion made of a magnetic material that is arranged inside the coil portion and in contact with the coil portion; a power source that flows a constant current into the coil portion; and a vibration detection unit that detects the vibrations based on changes in the AC component of the voltage generated in the conductor; the rotating shaft has a cylindrical outer surface that follows the rotation direction of the rotating shaft, and the main body portion has a ring-like shape that follows the circumferential direction of the coil portion and allows the rotating shaft to be inserted, or a shape with a portion of the ring-like shape cut out, and when the rotating shaft is arranged inside the main body portion so as to rotate in the circumferential direction of the coil portion, the portion of the rotating shaft that is arranged inside the main body portion is made of a material that is at least conductive or magnetic, and the inner surface of the main body portion is arranged spaced apart from the outer surface of the rotating shaft.

[0008] In one embodiment of the present invention, a rotating electric machine includes a rotor, a stator that houses the rotor and rotates the rotor, a rotating shaft that rotates together with the rotor, a bearing that supports the rotating shaft, and a vibration sensor unit that detects vibrations of the rotating shaft, the vibration sensor unit including a conductor having a coil portion wound in a circular coil shape, a main body made of a magnetic material that is arranged inside the coil portion and in contact with the coil portion, a power source that supplies a constant current to the coil portion, and a vibration detection unit that detects the vibrations based on changes in the AC component of a voltage generated in the conductor, the main body being shaped like an annulus along the circumferential direction of the coil portion, or a shape with a portion of the annulus cut out, through which the rotating shaft can be inserted, the rotating shaft being arranged inside the main body so as to rotate in the circumferential direction of the coil portion, and having a cylindrical outer circumferential surface that follows the rotational direction of the rotating shaft, The rotating electric machine is such that the portion arranged inside the main body is made of a material that is at least conductive or magnetic, and the inner surface of the main body is arranged spaced apart from the outer surface of the rotating shaft.

[0009] A pump device according to one embodiment of the present invention is a pump device including an impeller and the rotating electric machine according to the embodiment described above that rotates the impeller.

[0010] According to the present invention, it is possible to provide a vibration sensor unit, a rotating electrical machine, and a pump device that can be used over a wide temperature range and are less likely to suffer from breakdowns due to vibrations.

[0011] 6 is a schematic cross-sectional view showing an embodiment of a pump device according to the present invention. FIG. 6 is a schematic back view, as viewed by arrow A, of a partial configuration of a vibration sensor unit provided in the pump device of FIG. 1. FIG. 6 is a schematic cross-sectional view, as viewed by line BB, of the configuration shown in FIG. 2. FIG. 6 is a circuit configuration diagram of a vibration sensor unit provided in the pump device of FIG. 1. (a) is a schematic diagram showing an example of radial vibration of a rotating shaft provided in the pump device of FIG. 1, and (b) is a schematic diagram showing an example of thrust vibration of the rotating shaft. FIG. 6 is a schematic cross-sectional view showing another embodiment of a pump device according to the present invention. FIG. 6 is a schematic back view, as viewed by arrow C, of ​​a partial configuration of a vibration sensor unit provided in the pump device of FIG. 6. FIG. 6 is a schematic cross-sectional view, as viewed by line DD, of the configuration shown in FIG. 2. FIG. 6 is a circuit configuration diagram of a vibration sensor unit provided in the pump device of FIG. 6. FIG. 6 is a circuit configuration diagram showing a first modified example of a pump device according to the present invention. FIG. 6 is a schematic cross-sectional view, as viewed by line EE, of a main body and conductors provided in the pump device of FIG. 12. Fig. 10 is a schematic rear view showing a fifth modified example of the pump device according to the present invention. Fig. 11 is a schematic rear view showing a sixth modified example of the pump device according to the present invention. Fig. 12 is a circuit configuration diagram showing a seventh modified example of the pump device according to the present invention. Fig. 13 is a functional block diagram showing an eighth modified example of the pump device according to the present invention.

[0012] Embodiments of a vibration sensor unit, a rotating electrical machine, and a pump device according to the present invention will be described below. In the following description, reference will be made to the drawings as appropriate. In the drawings, identical members and elements are designated by the same reference numerals, and duplicated descriptions will be omitted. Furthermore, the dimensional proportions of the elements may be exaggerated for the sake of convenience, and are not limited to the proportions shown in the drawings.

[0013] In the following description, a wet motor pump (hereinafter simply referred to as the "pump") in which a pump section and a motor section are integrally configured will be described as an example of a pump device according to the present invention. The pump is a sealless motor pump that is structured to prevent leakage of the pumped fluid, and is structured so that the entire pump is immersed in the pumped fluid and some of the pumped fluid is also introduced into the motor section.

[0014] Pump Device (1) Configuration of Pump Device (1) First, an embodiment of a pump device according to the present invention (hereinafter simply referred to as "pump device") will be described below.

[0015] 1 is a schematic cross-sectional view showing an embodiment of a pump device. In the drawing, the flow of pumped fluid is indicated by white arrows. For ease of explanation, the drawing shows the pump device 1 in a simplified form.

[0016] The pump device 1 is used to pump a liquid (for example, water) and includes a pump section 2, a motor section 3, a control device 4, and a vibration sensor unit 5.

[0017] In the present invention, the handled liquid is not limited to water, but may be, for example, high-temperature oil or cryogenic liquefied gas (liquefied natural gas, liquefied hydrogen, etc.).

[0018] In the following description, the "forward direction" refers to the direction in which an impeller 26 (described later) is located relative to the motor unit 3, and the "rearward direction" refers to the opposite direction of the forward direction. The "downward direction" refers to the direction of gravity, and the "upward direction" refers to the opposite direction of the downward direction.

[0019] The pump unit 2 draws in and discharges pumped liquid and includes a housing 21, a pump chamber 22, a suction pipe 23, a discharge pipe 24, an internal flow path 25, and an impeller 26.

[0020] The housing 21 accommodates the motor unit 3 and defines a pump chamber 22, which accommodates the impeller 26, and an internal flow path 25. The housing 21 is made of, for example, stainless steel. The front end of the housing 21 extends cylindrically forward to form a suction pipe 23. The rear end of the housing 21 extends cylindrically rearward to form a discharge pipe 24. An internal flow path 25 is formed between the housing 21 and the motor unit 3 (a housing 31 described below) and extends along the front-to-rear direction. The internal flow path 25 communicates with the pump chamber 22 and the discharge pipe 24. In other words, the housing 21 defines the pump chamber 22, the suction pipe 23, the discharge pipe 24, and the internal flow path 25.

[0021] The suction pipe 23 is a flow path for the pumped liquid to be sucked into the pump chamber 22 .

[0022] The discharge pipe 24 is a flow path for the pumped liquid discharged from the pump chamber 22 .

[0023] The internal flow path 25 is a flow path through which the pumped liquid sucked from the suction pipe 23 into the pump chamber 22 is guided to the discharge pipe 24. The internal flow path 25 is formed between the housing 21 and a housing 31, which will be described later.

[0024] The impeller 26 is attached to a front end 320 of a rotary shaft 32, which will be described later, and rotates with the rotation of the rotary shaft 32. That is, the impeller 26 rotates with the rotation of the motor unit 3. As the impeller 26 rotates, it discharges the pumped fluid that has been sucked into the pump chamber 22 from the suction pipe 23 via the internal flow path 25 and the discharge pipe 24.

[0025] The motor unit 3 is driven under predetermined drive conditions to rotate the impeller 26 in the pump chamber 22. The motor unit 3 is housed in a housing 21. The motor unit 3 is an example of a rotating electric machine according to the present invention. The motor unit 3 includes a housing 31, a rotating shaft 32, two bearings 33 and 34, a rotor 35, a stator 36, and a motor chamber 37.

[0026] The housing 31 defines a motor chamber 37 that houses the rotary shaft 32, bearings 33 and 34, rotor 35, and stator 36. The housing 31 is made of stainless steel such as SUS304. The housing 31 has a front opening 310, a rear opening 311, and liquid inlets 312 and 313.

[0027] The front opening 310 is a hole that penetrates a front wall 314 of the housing 31 in the front-rear direction. The rear opening 311 is a hole that penetrates a rear wall 315 of the housing 31 in the front-rear direction.

[0028] The liquid inlets 312, 313 are holes that penetrate the peripheral wall 316 of the housing 31. The liquid inlets 312, 313 communicate with the internal flow path 25 and the motor chamber 37, and introduce the pumped liquid into the motor chamber 37. The liquid inlets 312, 313 are located, for example, in the front part of the peripheral wall 316.

[0029] In the present invention, the liquid inlets 312 and 313 may be disposed at the rear or central portion of the peripheral wall 316 .

[0030] In addition, in the present invention, the number of the liquid inlets 312 and 313 is not limited to two, and may be any number that can introduce the pumped liquid into the motor chamber 37 .

[0031] The rotating shaft 32 rotates in accordance with the rotation of the rotor 35 and transmits rotational power to the impeller 26. The rotating shaft 32 has, for example, a cylindrical shape. The rotating shaft 32 is made of a metal that is conductive and magnetic. In other words, the rotating shaft 32 is made of a conductive magnetic material.

[0032] In this specification, the "axial direction" refers to the direction along the axis of the rotary shaft 32, i.e., the front-rear direction. The "rotation direction" refers to the rotation direction of the rotary shaft 32, i.e., the circumferential direction of the rotary shaft 32.

[0033] The rotating shaft 32 is inserted through the rotor 35 and fixed to the rotor 35. The rotating shaft 32 is rotatably supported by bearings 33 and 34 with its axial direction oriented in the front-to-rear direction. The rotating shaft 32 is inserted through a front opening 310 and a rear opening 311 of the housing 31. A front end 320 of the rotating shaft 32 protrudes into the pump chamber 22. A rear end 321 of the rotating shaft 32 protrudes into the internal flow path 25 at the rear of the housing 31. The rotating shaft 32 has an outer circumferential surface 322 and a rear end surface 323. The outer circumferential surface 322 is cylindrical and extends along the circumferential direction (rotational direction) of the rotating shaft 32. The rear end surface 323 is flat and parallel to the left-right and up-down directions, and is an end surface perpendicular to the outer circumferential surface 322.

[0034] The bearings 33 and 34 are attached to the housing 31 and rotatably support the rotating shaft 32. The bearings 33 and 34 are, for example, known ball bearings. The bearing 33 supports the front portion of the rotating shaft 32, and the bearing 34 supports the rear portion of the rotating shaft 32.

[0035] The rotor 35 rotates due to a rotating magnetic field generated in the stator 36. The rotor 35 has a cylindrical shape. The rotor 35 is housed in the stator 36. When the rotor 35 rotates, the rotating shaft 32 rotates together with the rotor 35.

[0036] The stator 36 generates a rotating magnetic field that rotates the rotor 35. The stator 36 includes a cylindrical stator core 360 ​​and a plurality of motor windings 361. The inner peripheral surface of the stator core 360 ​​directly faces the outer peripheral surface of the rotor 35 in the radial direction of the rotating shaft 32.

[0037] The control device 4 controls the overall operation of the pump device 1. The control device 4 includes, for example, a processor such as a CPU (Central Processing Unit) 4a, a volatile memory such as a RAM (Random Access Memory) 4b that functions as a work area for the CPU 4a, a non-volatile memory such as a ROM (Read Only Memory) 4c that stores various types of operation information such as operation programs, and a storage unit 4d such as a flash memory that stores various types of detection information such as detection results described below.

[0038] The vibration sensor unit 5 detects vibration of the rotary shaft 32 of the motor section 3. The configuration of the vibration sensor unit 5 will be described later.

[0039] Vibration Sensor Unit (1) Configuration of the Vibration Sensor Unit (1) Figure 2 is a schematic rear view of a portion of the configuration of the vibration sensor unit 5 (the main body 6 and the conductor 7, which will be described later) as viewed from the arrow A in Figure 1. The figure shows a schematic rear view of the main body 6 and the conductor 7, and a functional block diagram of the vibration sensor unit 5. For ease of explanation, the figure also shows the rotation shaft 32. Figure 3 is a schematic cross-sectional view of the configuration (the main body 6 and the conductor 7) shown in Figure 2, taken along line BB. For ease of explanation, the figure also shows the rotation shaft 32 in a non-cross-sectional view. In the following description, Figure 1 will be referenced as appropriate.

[0040] The vibration sensor unit 5 includes a main body 6, a conductor 7, a circuit board 8, and a spacer 9. The main body 6 and the conductor 7 constitute a sensing section that generates a signal (an induced current, which will be described later) corresponding to the vibration of the rotating shaft 32. The circuit board 8 constitutes a signal processing section that applies a constant current to the sensing section and performs predetermined signal processing on the signal generated by the sensing section to detect the vibration of the rotating shaft 32.

[0041] The main body 6 functions as a so-called yoke, which serves as a path for magnetic flux generated in the magnetic field around the conductor 7 when a constant current from the power source 81 flows through the conductor 7. The main body 6 is made of a magnetic metal (e.g., iron). That is, the main body 6 is made of a magnetic material. The main body 6 has a circular ring shape when viewed from the front to back. The main body 6 has an outer peripheral surface 60, an inner peripheral surface 61, and two protrusions 62 and 63.

[0042] In the present invention, the main body 6 may be made of a magnetic alloy (for example, low carbon steel, SUS430, etc.).

[0043] The outer peripheral surface 60 has a cylindrical shape, and the inner peripheral surface 61 has a substantially cylindrical shape.

[0044] A portion of the inner circumferential surface 61 (in this embodiment, the upper end) protrudes radially inward (downward) of the main body 6, forming a protrusion 62. Another portion of the inner circumferential surface 61 (in this embodiment, the right end) protrudes radially inward (leftward) of the main body 6, forming a protrusion 63. That is, in a rear view, the protrusion 63 is located 90° clockwise from the protrusion 62 along the circumferential direction of the main body 6. In other words, the protrusions 62, 63 are located 90° apart from each other in the circumferential direction of the main body 6. The shapes of the protrusions 62, 63 are the same except for the different protrusion directions. An end face (lower end face) 64 of the protrusion 62 is flat and parallel to the front-rear and left-right directions and constitutes part of the inner circumferential surface 61. An end face (left end face) 65 of the protrusion 63 is flat and parallel to the front-rear and left-right directions and constitutes part of the inner circumferential surface 61. That is, the inner circumferential surface 61 includes a surface (hereinafter referred to as a "first surface 66") other than the end surfaces 64, 65 and the protrusions 62, 63. The end surfaces 64, 65 are an example of the second surface in the present invention.

[0045] The radius of the inscribed circle IC1 of the end faces 64, 65 is larger than the radius of the rotation shaft 32 and smaller than the radius of the first surface 66. The radius of the first surface 66 is larger than the radius of the rotation shaft 32. That is, the diameter of the inscribed circle IC1 is larger than the diameter (outer diameter) of the rotation shaft 32 and smaller than the inner diameter of the first surface 66. In other words, the inner circumferential surface 61 includes a first surface 66 having a radius larger than the radius of the rotation shaft 32, and end faces 64, 65 whose distance from the center of curvature of the first surface 66 is smaller than the radius of the first surface 66. Therefore, the rotation shaft 32 can be inserted into the main body 6. In a rear view, the inscribed circle IC1 is arranged concentrically with the outer circumferential surface 60 and the first surface 66. The radius of the first surface 66 is an example of the first radius in the present invention.

[0046] The main body 6 is disposed rearward of the housing 31 and is attached to the outer surface of the rear wall 315 of the housing 31 via a spacer 9 using, for example, bolts (not shown) made of a non-magnetic material (e.g., SUS304). The rear end 321 and rear end face 323 of the rotating shaft 32 are disposed inside the main body 6. In a rear view, the outer peripheral surface 60 (inscribed circle IC1, first face 66) of the main body 6 is disposed concentrically with the outer peripheral surface 322 of the rotating shaft 32. That is, the rotating shaft 32 is disposed inside the main body 6 so as to rotate in the circumferential direction of the main body 6 (coil portion 70). In the front-rear direction, the rear end face 323 of the rotating shaft 32 is disposed at the center of the main body 6. That is, the front half of the inner peripheral surface 61 (end faces 64, 65, first face 66) of the main body 6 faces the outer peripheral surface 322 of the rear end 321 of the rotating shaft 32 and is disposed spaced apart from the outer peripheral surface 322. In other words, in the radial direction of the rotating shaft 32, the main body 6 (protrusions 62, 63) is disposed outward from the rear end 321 of the rotating shaft 32. In addition, in the circumferential direction of the rotating shaft 32, the main body 6 covers the entire circumference of the outer circumferential surface 322 of the rear end 321 of the rotating shaft 32. When the bearings 33, 34 are not worn, the gap between the outer circumferential surface 322 and the end face 64 (hereinafter referred to as "gap G1: see FIG. 5 ; the same applies hereinafter") is the same as the gap between the outer circumferential surface 322 and the end face 65 (hereinafter referred to as "gap G2: see FIG. 5 ; the same applies hereinafter").

[0047] When a current from a power source 81 flows through the conductor 7, the conductor 7 generates a magnetic flux used to detect vibration of the rotating shaft 32. The conductor 7 is, for example, a copper wire coated with polyimide resin. The conductor 7 includes a coil portion 70 and two lead portions 71 and 72.

[0048] The central portion of the conducting wire 7 is wound in a coil shape around the outer circumferential surface 60 of the main body 6, forming the coil portion 70. That is, the main body 6 has a circular ring shape that follows the circumferential direction of the coil portion 70. The main body 6 is disposed inside the coil portion 70 in the radial direction of the coil portion 70 and in contact with the coil portion 70. In a rear view, the coil portion 70 is disposed concentrically with the outer circumferential surface 322 of the rotating shaft 32. In other words, the rotating shaft 32 is disposed inside the main body 6 and the coil portion 70 so that the rotating shaft 32 rotates in the circumferential direction of the coil portion 70. In the front-rear direction, the length of the coil portion 70 is shorter than the length of the main body 6.

[0049] In the present invention, the length of the coil portion 70 in the front-rear direction may be the same as the length of the main body portion 6 .

[0050] The portions of the conductor 7 excluding the coil portion 70 form lead-out portions 71 and 72. The lead-out portions 71 and 72 are covered, for example, with an insulating tube. The lead-out portions 71 and 72, together with the wiring of the motor portion 3 (not shown), are led to the outside of the housing 21 via a known terminal block that is airtight and pressure-resistant.

[0051] Fig. 4 is a circuit diagram of the vibration sensor unit 5. In the following description, Fig. 1 and Fig. 2 will be referred to as appropriate.

[0052] The circuit board 8 is a known printed wiring board on which electronic components 80 (capacitor C1, operational amplifier OA1, and A / D conversion circuit AD1), a power supply 81, and an arithmetic unit 82 are mounted. That is, the vibration sensor unit 5 also includes the electronic components 80, the power supply 81, and the arithmetic unit 82. The circuit board 8 includes a terminal T1 connected to the draw-out portion 71 and a terminal T2 connected to the draw-out portion 72.

[0053] The non-inverting input of the operational amplifier OA1 is connected to terminal T1, and the inverting input is connected to terminal T2 via contact P3 and is also grounded. One end of a power supply 81 is connected between terminal T1 (lead 71) and the non-inverting input via contact P1. The other end of the power supply 81 is connected between terminal T2 (lead 72) and the inverting input via contact P2. A capacitor C1 is connected between one end (contact P1) of the power supply 81 and the non-inverting input. The output terminal of the operational amplifier OA1 is connected to an arithmetic unit 82 via an A / D conversion circuit AD1.

[0054] The power supply 81 is a known constant current power supply circuit that supplies a constant DC current to the coil portion 70 .

[0055] 2 will be mainly referred to in the following description. The arithmetic unit 82 detects vibration of the rotating shaft 32 based on changes in the AC component of the voltage generated in the coil portion 70 in response to vibration of the rotating shaft 32. The arithmetic unit 82 includes, for example, a processor such as a CPU 82a, volatile memory such as a RAM 82b that functions as a work area for the CPU 82a, and non-volatile memory such as a ROM 82c that stores various types of operation information such as detection programs. The arithmetic unit 82 includes an acquisition unit 820 and a vibration detection unit 821.

[0056] A detection program that detects vibrations of the rotating shaft 32 runs in the arithmetic unit 82, and the detection program cooperates with the hardware resources of the vibration sensor unit 5 to detect vibrations of the rotating shaft 32. By causing a processor (CPU 82a) constituting the arithmetic unit 82 to execute the detection program, the detection program can cause the processor to function as an acquisition unit 820 and a vibration detection unit 821, and can cause the processor to execute a vibration detection method. Similarly, by causing a computer to execute the detection program, the detection program can cause the computer to function as the arithmetic unit 82.

[0057] The acquiring unit 820 acquires a signal (a vibration signal, which will be described later) that has been converted into a digital signal by the A / D conversion circuit AD1. Specific operations of the acquiring unit 820 will be described later.

[0058] The vibration detection unit 821 detects vibration of the rotating shaft 32 based on the signal acquired by the acquisition unit 820. The specific operation of the vibration detection unit 821 will be described later.

[0059] The spacer 9 assists in attaching the main body 6 to the housing 31, and also prevents leakage of magnetic flux from the main body 6 to the housing 31 when the housing 31 is made of a magnetic material. The spacer 9 is made of a non-magnetic material such as SUS304. The spacer 9 is shaped like a ring plate. A front surface 9a of the spacer 9 has an uneven surface that matches the shape of the rear surface of the housing 31, and a rear surface 9b of the spacer 9 is flat.

[0060] In the present invention, when the housing 31 is made of a non-magnetic material, the vibration sensor unit 5 does not need to include the spacer 9. In this case, the portion of the outer surface of the rear wall 315 of the housing 31 that contacts the main body 6 may be flat.

[0061] Vibration Detection Principle Next, the principle of detection of vibration of the rotating shaft 32 in the vibration sensor unit 5 will be described. In this embodiment, the vibration sensor unit 5 detects vibration of the rotating shaft 32 in the diameter direction (radial direction) of the rotating shaft 32 (hereinafter referred to as "radial vibration") and vibration of the rotating shaft 32 in the axial direction (thrust direction) of the rotating shaft 32 (hereinafter referred to as "thrust vibration"). In the following description, Figures 1 to 4 will be referenced as appropriate.

[0062] 5A is a schematic diagram showing an example of radial vibration of the rotating shaft 32, and FIG. 5B is a schematic cross-sectional view showing an example of thrust vibration of the rotating shaft 32. In the figure, the vibration of the rotating shaft 32 is illustrated by a two-dot chain line.

[0063] When a direct current from the power source 81 flows through the conductor 7, a magnetic field is formed around the coil portion 70 (a magnetic field is generated). As described above, since the main body portion 6 is made of a magnetic material, most of the magnetic flux in this magnetic field is concentrated within the main body portion 6. Furthermore, some of the magnetic flux also passes through the rotating shaft 32 via the gaps G1 and G2 between the rotating shaft 32 and the protrusions 62 and 63. When the rotating shaft 32 is not vibrating radially, the amount of magnetic flux passing through the rotating shaft 32 remains almost constant. Generally, when the magnetic flux passing through a coil with "N" turns changes by "ΔΦ" over a predetermined time "Δt", the induced electromotive force "V" generated in the coil is expressed by the following equation (1):

[0064] V=-N×(ΔΦ / Δt) (1)

[0065] That is, the induced electromotive force "V" increases as the change (increase or decrease) in the magnetic flux becomes more rapid, decreases as the change in the magnetic flux becomes more gradual, and becomes "0" when there is no change in the magnetic flux. Therefore, when the rotating shaft 32 is not vibrating radially, the induced electromotive force "V" generated in the coil portion 70 is approximately "0".

[0066] As described above, the main body 6 covers the entire circumference of the rear end 321 of the rotating shaft 32 in the circumferential direction of the rotating shaft 32. The protrusions 62 and 63 are positioned 90° apart from each other in the circumferential direction of the rotating shaft 32. Therefore, when the rotating shaft 32 vibrates radially, the rotating shaft 32 repeatedly approaches and moves away from the protrusions 62 and / or the protrusions 63 in an extremely short time. That is, the gap G1 and / or the gap G2 (hereinafter simply referred to as "gaps G1 and G2") increases and decreases (changes) in an extremely short time. At this time, the permeance of magnetic flux through the gaps G1 and G2 changes, and the inductance of the coil 70 changes accordingly. That is, the inductance of the coil 70 changes according to the increase or decrease in the gaps G1 and G2. That is, for example, as the rotating shaft 32 approaches the protruding portions 62, 63 (as the gaps G1, G2 decrease), the magnetic flux passes more easily through the gaps G1, G2. At this time, the magnetic flux passing through the rotating shaft 32 increases, and the magnetic flux linking with the coil portion 70 changes (increases). On the other hand, for example, as the rotating shaft 32 moves away from the protruding portions 62, 63 (as the gaps G1, G2 increase), the magnetic flux passing through the gaps G1, G2 becomes more difficult. At this time, the magnetic flux passing through the rotating shaft 32 decreases, and the magnetic flux linking with the coil portion 70 changes (decreases). In response to this change in the ease with which the magnetic flux passes over time, the induced electromotive force generated in the coil portion 70 changes, and an induced current corresponding to the induced electromotive force flows in the coil portion 70.

[0067] As shown in Equation (1), the magnitude of the induced electromotive force corresponds to (is proportional to) the rate of change of the magnetic flux. That is, the induced electromotive force increases as the rate of change of the magnetic flux increases, and decreases as the rate of change of the magnetic flux decreases. In other words, the voltage of the induced current flowing through the coil portion 70 due to the generation of the induced electromotive force increases as the displacement speed (vibration speed) of the rotating shaft 32, i.e., the magnitude of the displacement (vibration) per unit time, increases, and decreases as the displacement speed (vibration speed) of the rotating shaft 32, i.e., the magnitude of the displacement (vibration) per unit time, decreases. Also, as shown in Equation (1), the induced electromotive force is generated in a direction that cancels out the change in the magnetic flux. Therefore, the positive and negative signs of the induced electromotive force alternate with a period corresponding to the period of the radial vibration. Therefore, the voltage of the induced current includes an AC component corresponding to the radial vibration, and the voltage value indicates the magnitude of the radial vibration. In other words, the induced current generated in the coil portion 70 due to the radial vibration functions as a vibration signal indicating the speed of the radial vibration (change in the AC component). At this time, a DC voltage is generated across both ends of the conductor 7 (between terminals T1 and T2) by multiplying the DC current by the resistance of the conductor 7, but this DC voltage is not transmitted to the operational amplifier OA1 by the capacitor C1.

[0068] Next, when the rotating shaft 32 is not thrust vibrating, the area where the outer peripheral surface 322 of the rotating shaft 32 faces the inner peripheral surface 61 of the main body 6 (hereinafter referred to as the "facing area A1") is constant. On the other hand, when the rotating shaft 32 is thrust vibrating, the rotating shaft 32 is displaced in the front-rear direction within an extremely short period of time, and the rear end surface 323 of the rotating shaft 32 moves forward and backward inside the main body 6. At this time, the facing area A1 increases or decreases according to the displacement of the rotating shaft 32 (rear end surface 323). That is, for example, when the rotating shaft 32 is displaced rearward, the facing area A1 increases, and when the rotating shaft 32 is displaced forward, the facing area A1 decreases. The magnetic flux passing through the rotating shaft 32 changes according to the increase or decrease in the facing area A1. That is, for example, as the facing area A1 increases, the magnetic flux passing through the rotating shaft 32 increases, and the magnetic flux linking with the coil portion 70 changes (increases). On the other hand, for example, as the facing area A1 decreases, the magnetic flux passing through the rotating shaft 32 decreases, and the magnetic flux linking to the coil portion 70 changes (decreases). The induced electromotive force generated in the coil portion 70 changes in accordance with the change in the facing area A1 over time, and a current (vibration signal) corresponding to the induced electromotive force flows in the coil portion 70. As a result, similar to the case of radial vibration, the induced current generated in the coil portion 70 by the thrust vibration functions as a vibration signal indicating the speed of the thrust vibration (change in the AC component).

[0069] In this way, the vibration sensor unit 5 detects vibrations not based on the physical distortion (displacement) of the sensing section caused by vibration, but rather based on electrical displacement using electromagnetic induction, without contacting the vibration source. Therefore, the vibration sensor unit 5 does not need to transmit the vibration of the rotating shaft 32 to the sensing section itself. Therefore, the vibration sensor unit 5 is less likely to detect unintended vibrations (other than the vibration of the rotating shaft 32), and is less likely to experience false detections due to unintended vibrations or malfunctions of the sensing section due to vibrations. Furthermore, the sensing section is composed only of a coil (coil section 70) and a yoke (main body section 6). Therefore, the sensing section can be used in a wide temperature range, from extremely low to high temperatures, and is less likely to malfunction.

[0070] Furthermore, since the main body 6 is provided with the protrusions 62, 63, an induced electromotive force is more likely to be generated in the coil 70 when the rotating shaft 32 vibrates so as to approach the end faces 64, 65. Therefore, the vibration detection sensitivity of the vibration detection unit 821 is improved compared to the vibration detection sensitivity when the main body 6 does not have the protrusions 62, 63.

[0071] In the present invention, both radial vibration and thrust vibration are detected based on changes in the AC component of the voltage of the induced electromotive force generated in the coil portion 70. Therefore, although the vibration sensor unit 5 can detect radial vibration and thrust vibration, it is not easy to determine whether the vibration is radial vibration or thrust vibration.

[0072] Operation of the Pump Device (1) Next, the operation of the pump device 1 will be described below, focusing on the operation of the vibration sensor unit 5. In the following description, reference will be made to Figures 1 to 5 as appropriate.

[0073] When the pump device 1 is operating, the rotating shaft 32 rotates together with the rotor 35. The power supply 81 applies a constant DC current to the conductor 7 (coil portion 70). When the bearings 33 and 34 are not worn and the rotating shaft 32 is not vibrating, no induced electromotive force is generated in the coil portion 70.

[0074] Next, when bearings 33 and 34 are worn and rotating shaft 32 vibrates (radial vibration and / or thrust vibration), an induced electromotive force corresponding to the vibration is generated in coil unit 70, causing an induced current (vibration signal) to flow. At this time, capacitor C1 prevents DC current (constant current) from power supply 81 from flowing into operational amplifier OA1. As a result, only the vibration signal flows through operational amplifier OA1, which amplifies and outputs changes in the AC component of the voltage contained in the vibration signal. The output from operational amplifier OA1 (the amplified vibration signal) is converted into a digital signal by A / D conversion circuit AD1, input to calculation unit 82, and acquired by acquisition unit 820.

[0075] The vibration detection unit 821 detects vibration of the rotating shaft 32 based on the vibration signal (a signal indicating a change in the AC component of the voltage) acquired by the acquisition unit 820. Specifically, the vibration detection unit 821 acquires the rate of change of voltage based on the vibration signal over a predetermined period (e.g., several seconds). As described above, the magnitude of the induced electromotive force corresponds to the rate of change of the magnetic flux, i.e., the rate of change of the displacement of the rotating shaft 32. Therefore, the vibration detection unit 821 can indirectly acquire the rate of change of the displacement of the rotating shaft 32 by acquiring the rate of change of the voltage. Furthermore, as described above, an induced electromotive force is not generated unless the rotating shaft 32 vibrates. Therefore, the vibration detection unit 821 can determine whether or not the rotating shaft 32 is vibrating and detect the vibration, for example, by determining whether the voltage value of the vibration signal is equal to or greater than a predetermined threshold.

[0076] Next, the vibration detection unit 821 acquires vibration information (vibration period, acceleration, and displacement amount) of the rotating shaft 32 based on the acquired rate of change of voltage. Specifically, the vibration detection unit 821 acquires the vibration period of the rotating shaft 32, for example, by performing known FFT processing and filter processing on the rate of change of voltage. The vibration detection unit 821 also acquires the acceleration of the vibration of the rotating shaft 32, for example, by differentiating the rate of change of voltage with respect to time using known differentiation processing. Furthermore, the vibration detection unit 821 acquires the displacement amount of the vibration of the rotating shaft 32, for example, by integrating the rate of change of voltage with respect to time using known integration processing. The acquired vibration information is stored, for example, in the storage unit 4d.

[0077] Here, for example, when the cause of vibration of the rotating shaft 32 is damage to a portion of the balls of the bearings 33 and 34, the rotating shaft 32 vibrates at a small period corresponding to the position of the damaged ball. Furthermore, when the cause of vibration of the rotating shaft 32 is normal wear of the bearings 33 and 34, the vibration of the rotating shaft 32 is at a larger period than the period when the balls are damaged. Thus, the vibration period of the rotating shaft 32 is information that can contribute to predicting the cause of vibration of the rotating shaft 32. Therefore, if the correlation between the vibration period and the cause of vibration is identified in advance, the pump device 1 can identify the cause of vibration of the rotating shaft 32 based on the vibration period of the rotating shaft 32.

[0078] In addition, based on the acceleration of the vibration of the rotating shaft 32, the pump device 1 can estimate whether the cause of the vibration of the rotating shaft 32 is damage to the bearings 33, 34 (the acceleration tends to be large) or wear of the bearings 33, 34 (the acceleration tends to be small).

[0079] Furthermore, the pump device 1 can estimate the amount of wear of the bearings 33, 34 based on the amount of displacement of the vibration of the rotating shaft 32. Therefore, the pump device 1 can display the amount of wear of the bearings 33, 34 using a display device (not shown) such as an indicator.

[0080] Furthermore, when viewed in the front-rear direction (when viewed in the axial direction of the rotating shaft 32), the main body 6 is disposed substantially concentrically with the stator 36 (the stator core 360 ​​and the motor windings 361), and is disposed rearward of the stator 36 in the front-rear direction. In this configuration, even if magnetic flux leakage (rotating magnetic flux) occurs from the rotating magnetic field of the stator 36, the leakage rotates in the circumferential direction of the rotating shaft 32, and the main body 6 is also annular and extends in the same circumferential direction. Therefore, the total amount of the leakage crossing the coil 70 in the circumferential direction does not change, and the coil 70 is less likely to generate induced electromotive force due to the leakage (less likely to generate noise due to the leakage).

[0081] Summary (1) According to the embodiment described above, the vibration sensor unit 5 includes a main body 6, a conductive wire 7, and a vibration detection unit 821. The main body 6 is made of a magnetic material and has a circular ring shape through which the rotating shaft 32 can be inserted. The conductive wire 7 includes one coil 70 wound in a coil shape around the outer circumferential surface 60 of the main body 6. The rotating shaft 32 is made of a conductive magnetic material and has a cylindrical outer circumferential surface 322 that extends along the circumferential direction (rotational direction) of the rotating shaft 32. The rotating shaft 32 is disposed inside the main body 6 (coil 70) so as to rotate in the circumferential direction of the main body 6 (coil 70). The inner circumferential surface 61 of the main body 6 is disposed apart from the outer circumferential surface 322 of the rotating shaft 32 and directly faces the outer circumferential surface 322. The vibration detection unit 821 detects vibration of the rotating shaft 32 based on changes in the AC component of the voltage generated in the conductive wire 7 (coil 70). With this configuration, when the rotating shaft 32 vibrates radially, the distance between the outer circumferential surface 322 of the rotating shaft 32 and the inner circumferential surface 61 of the main body 6 increases or decreases (changes) within a very short period of time. At this time, the induced electromotive force generated in the coil 70 changes, and an induced current (vibration signal) corresponding to the induced electromotive force flows through the coil 70. The voltage of the induced current flowing through the coil 70 contains an AC component corresponding to the radial vibration, and the voltage value indicates the speed of the radial vibration. The vibration detection unit 821 can determine the presence or absence of vibration of the rotating shaft 32 and detect the vibration, for example, by determining whether the voltage value of the vibration signal is equal to or greater than a predetermined threshold. Furthermore, the vibration detection unit 821 can acquire vibration information (vibration period, acceleration, and displacement) of the rotating shaft 32 based on the rate of change of the acquired voltage. In this way, the vibration sensor unit 5 detects vibration based on electrical displacement using electromagnetic induction, rather than based on physical distortion (displacement) of the sensing unit caused by the vibration. Therefore, in the vibration sensor unit 5, it is not necessary to transmit the vibration of the rotating shaft 32 to the sensing section itself. Therefore, the vibration sensor unit 5 is unlikely to detect unintended vibrations (other than the vibration of the rotating shaft 32), and false detections due to unintended vibrations and failures of the sensing section due to vibrations are unlikely to occur. In addition, the sensing section is composed only of a coil (coil section 70) and a yoke (main body section 6).Therefore, the sensing unit can be used in a wide temperature range from extremely low to high temperatures, and temperature-related failures are unlikely to occur. In this way, the present invention can realize a vibration sensor unit 5 (motor unit 3, pump device 1) that can be used in a wide temperature range and is unlikely to fail due to vibration or temperature.

[0082] Furthermore, according to the embodiment described above, the inner circumferential surface 61 of the main body 6 includes a first surface 66 having a first radius larger than the radius of the rotating shaft 32, and end surfaces 64, 65 whose distance from the center of curvature of the first surface 66 is smaller than the first radius. The end surfaces 64, 65 are positioned 90° apart from each other in the circumferential direction of the main body 6 (coil portion 70). With this configuration, the distance (gaps G1, G2) between the end surfaces 64, 65 and the outer circumferential surface 322 is smaller than the distance between the first surface 66 and the outer circumferential surface 322. Therefore, when the rotating shaft 32 vibrates to approach the end surfaces 64, 65, an induced electromotive force is likely to be generated in the coil portion 70. Therefore, the vibration detection sensitivity of the vibration detection unit 821 is improved compared to when the main body 6 does not include the protrusions 62, 63.

[0083] Furthermore, according to the embodiment described above, the main body 6 includes protrusions 62, 63, which are parts of the inner circumferential surface 61 that protrude inward in the radial direction of the main body 6 (coil portion 70). End face 64 is located on protrusion 62, and end face 65 is located on protrusion 63. According to this configuration, simply by forming protrusions 62, 63 on the inner circumferential surface 61, the vibration detection sensitivity of the vibration detection unit 821 can be easily improved.

[0084] Furthermore, according to the embodiment described above, the rotating shaft 32 has a rear end surface 323 that is parallel to the radial direction of the rotating shaft 32 and perpendicular to the outer circumferential surface 322 of the rotating shaft 32. The rotating shaft 32 is disposed inside the main body 6 (coil portion 70) so as to rotate in the circumferential direction of the main body 6. The rear end surface 323 is disposed inside the main body 6. With this configuration, the facing area A1 increases when the rotating shaft 32 is displaced rearward, and decreases when the rotating shaft 32 is displaced forward. The magnetic flux passing through the rotating shaft 32 changes in response to the increase or decrease in the facing area A1. The induced electromotive force generated in the coil portion 70 changes in response to the change in the facing area A1 over time, and a current (vibration signal) corresponding to the induced electromotive force flows through the coil portion 70. The voltage of the induced current flowing through the coil portion 70 includes an AC component corresponding to the thrust vibration, and the voltage value indicates the speed of the thrust vibration. The vibration detection unit 821 can detect vibration by determining whether or not the voltage value of the vibration signal is equal to or greater than a predetermined threshold, for example. The vibration detection unit 821 can also obtain vibration information (vibration period, acceleration, and displacement) about the rotating shaft 32 based on the rate of change of the obtained voltage. Thus, with this configuration, the vibration sensor unit 5 can detect thrust vibration as well as radial vibration.

[0085] Furthermore, according to the embodiment described above, the rotating shaft 32 is made of a magnetic material, and the power supply 81 is a constant-current power supply circuit that passes a constant DC current through the coil portion 70. With this configuration, a magnetic field can be easily formed around the coil portion 70. The constant current flowing through the coil portion 70 passes a stable magnetic flux through the main body 6 and the rotating shaft 32 when the rotating shaft 32 is not vibrating, and generates a change in the magnetic flux according to the vibration when the rotating shaft 32 is vibrating. This change in magnetic flux generates an induced electromotive force in the coil portion 70, and the vibration detection unit 821 can detect the vibration of the rotating shaft 32 based on the change in the AC component of the voltage generated in the conductor 7 (coil portion 70).

[0086] Pump Device (2) Next, another embodiment of a pump device (hereinafter referred to as the "second embodiment") will be described below, focusing on the differences from the previously described embodiment (hereinafter referred to as the "first embodiment"). In the second embodiment, the configuration of the vibration sensor unit differs from that of the first embodiment. In the following description of the second embodiment, for convenience of explanation, the same components as in the first embodiment and components having common functions are assigned the same reference numerals as in the first embodiment, unless otherwise specified, and their description will be omitted.

[0087] Configuration of the pump device (2) Fig. 6 is a schematic cross-sectional view showing a second embodiment of the pump device. In the figure, the flow of pumped fluid is indicated by white arrows. For ease of explanation, the figure shows the pump device 1A in a simplified form.

[0088] The pump device 1A is used to pump a liquid (for example, water) and includes a pump section 2, a motor section 3, a control device 4, and a vibration sensor unit 5A.

[0089] Vibration Sensor Unit (2) Configuration of Vibration Sensor Unit (2) Figure 7 is a schematic rear view of a portion of the configuration of the vibration sensor unit 5A (the main body 6 and the conductor 7A described below) as viewed from the arrow C in Figure 6. This figure shows a schematic rear view of the main body 6 and the conductor 7A, as well as a functional block diagram of the vibration sensor unit 5A. For ease of explanation, this figure also shows the rotation shaft 32. Figure 8 is a schematic cross-sectional view of the configuration (the main body 6 and the conductor 7A) shown in Figure 7 along line DD. For ease of explanation, this figure also shows the rotation shaft 32 in a non-cross-sectional view. In the following description, Figure 6 will be referenced as appropriate.

[0090] The vibration sensor unit 5A includes a main body 6, a conductor 7A, a circuit board 8A (electronic components 80A, a power supply 81A, and an arithmetic unit 82A), and a spacer 9. The main body 6 and the conductor 7A constitute a sensing unit that generates a signal (an induced current, described below) corresponding to the vibration of the rotating shaft 32. The circuit board 8A (electronic components 80A, a power supply 81A, and an arithmetic unit 82A) constitutes a signal processing unit that applies current to the sensing unit and performs predetermined signal processing on the signal generated by the sensing unit to detect the vibration of the rotating shaft 32 and the temperature of the conductor 7A. In the vibration sensor unit 5A, the configurations of the conductor 7A and the circuit board 8A differ from those of the vibration sensor unit 5 of the first embodiment.

[0091] The main body 6 has an outer circumferential surface 60 , an inner circumferential surface 61 , and two protrusions 62 and 63 .

[0092] Conductor 7A includes a coil portion 70A, two lead-out portions 71 and 72, and an intermediate lead-out portion 73. Of conductor 7A, coil portion 70A and two lead-out portions 71 and 72 are composed of two types of conductor wire 701 and 702. Specifically, half of coil portion 70A and lead-out portion 71 are composed of conductor wire 701, and the other half of coil portion 70A and lead-out portion 72 are composed of conductor wire 702. Conductor wire 702 is connected to conductor wire 701 at connection point 7P (see FIG. 9 ; the same applies below) so as to form a single conductor wire 7A together with conductor wire 701. The length of conductor wire 701 is the same as the length of conductor wire 702.

[0093] Conductive wire 701 is, for example, a copper wire coated with polyimide resin. Conductive wire 702 is, for example, a nickel wire coated with polyimide resin. That is, conductive wire 701 contains copper as a main component, and conductive wire 702 contains nickel as a main component. Copper is an example of the first metal in the present invention, and nickel is an example of the second metal in the present invention.

[0094] In the present invention, it is sufficient that one of the conductors 701 and 702 is made of a metal with a relatively small temperature change rate of resistance (resistance temperature coefficient), and the other is made of a metal with a relatively large temperature change rate of resistance, and the main components of the conductors 701 and 702 are not limited to copper and nickel.

[0095] The central portion of the conductor wire 7 is wound in a coil shape around the outer circumferential surface 60 of the main body 6 to form a coil portion 70A. Half of the coil portion 70A is a first coil portion 74 formed by a conductor wire 701, and the other half is a second coil portion 75 formed by a conductor wire 702. That is, of both ends of the first coil portion 74, one end is a connection point 7P, and the other end is continuous with the lead-out portion 71. Of both ends of the second coil portion 75, one end is a connection point 7P, and the other end is continuous with the lead-out portion 72. The first coil portion 74 is wound directly around the outer circumferential surface 60, and the second coil portion 75 is wound around the first coil portion 74. That is, the coil portion 70A is doubly wound with the first coil portion 74 and the second coil portion 75. In the circumferential direction of the coil portion 70A, the first coil portion 74 is wound in the same direction as the second coil portion 75. In this manner, the coil portion 70A includes the first coil portion 74 and the second coil portion 75.

[0096] The intermediate lead portion 73 is, for example, a copper wire coated with polyimide resin. The intermediate lead portion 73 is connected to the connection point 7P and, like the lead portions 71 and 72, is led to the circuit board 8A via a terminal block or the like.

[0097] In the present invention, intermediate lead-out portion 73 may be configured integrally with conductor 701 or conductor 702. In this case, conductor 701 or conductor 702 is connected to the boundary between intermediate lead-out portion 73 and first coil portion 74 or second coil portion 75. Even in this configuration, intermediate lead-out portion 73 is connected to connection point 7P between conductor 701 and conductor 702.

[0098] In the present invention, the coil portion 70A does not have to be double-wound. That is, for example, in the front-rear direction, the front half of the coil portion 70A may be made up of the first coil portion 74, and the rear half may be made up of the second coil portion 75.

[0099] 9 is a circuit diagram of the vibration sensor unit 5 A. In the following description, FIGS. 6 to 8 will be referred to as appropriate.

[0100] The circuit board 8A is a known printed wiring board on which electronic components 80A (capacitors C1 and C2, resistors R1 and R2, operational amplifiers OA1 and OA2, and an A / D conversion circuit AD1), a power supply 81A, and an arithmetic unit 82A are mounted. The circuit board 8A has terminals T1 and T2 and a terminal T3 connected to the intermediate lead-out portion 73.

[0101] The non-inverting input of operational amplifier OA1 is connected to terminal T1, and the inverting input is connected to terminal T2. The non-inverting input of operational amplifier OA2 is connected to terminal T1, and the inverting input is connected to terminal T2 and the inverting input of operational amplifier OA1 via contact P14. One end of a power supply 81A (a first power supply 810 described below) is connected between terminal T1 (lead-out portion 71) and each non-inverting input via contact P11. The other end of power supply 81A (a second power supply 811 described below) is connected between terminal T2 (lead-out portion 72) and each inverting input via contact P12. The other end of the first power supply 810 and one end of the second power supply 811 are connected to terminal T3 via contact P15 and are also grounded. Capacitor C1 is connected between one end of power supply 81A and the non-inverting input of operational amplifier OA1 via contact P13. Capacitor C2 is connected between the other end of power supply 81A and the inverting input of operational amplifier OA1 via contact P14. One end of resistor R1 is connected between capacitor C1 and the non-inverting input of operational amplifier OA2 via contact P16. One end of resistor R2 is connected between capacitor C2 and the inverting input of operational amplifier OA2 via contact P17. The other ends of resistors R1 and R2 are grounded via contact P18.

[0102] The power supply 81A includes a first power supply 810 that supplies a constant DC current to the first coil portion 74, and a second power supply 811 that supplies a constant DC current to the second coil portion 75. The first power supply 810 and the second power supply 811 are known constant current power supply circuits. The other ends of the first power supply 810 and the second power supply 811 are connected to the terminal T3 and are also grounded.

[0103] 7 will be mainly referred to in the following description. The arithmetic unit 82A detects vibration of the rotating shaft 32 based on changes in the AC component of the voltage generated in the coil portion 70A in response to the vibration of the rotating shaft 32. The arithmetic unit 82A includes, for example, a processor such as a CPU 82a, volatile memory such as a RAM 82b that functions as a work area for the CPU 82a, and non-volatile memory such as a ROM 82c that stores various types of operation information such as detection programs. The arithmetic unit 82A includes an acquisition unit 820, a vibration detection unit 821, and a temperature detection unit 822.

[0104] A detection program for detecting the vibration of the rotating shaft 32 and the temperature of the coil portion 70A runs in the arithmetic unit 82A, and the detection program cooperates with the hardware resources of the vibration sensor unit 5A to detect the vibration of the rotating shaft 32 and the temperature of the coil portion 70A. By causing a processor (CPU 82a) constituting the arithmetic unit 82A to execute the detection program, the detection program causes the processor to function as an acquisition unit 820, a vibration detection unit 821, and a temperature detection unit 822, thereby causing the processor to execute a vibration detection method and a temperature detection method. Similarly, by causing a computer to execute the detection program, the detection program causes the computer to function as the arithmetic unit 82A.

[0105] The acquiring unit 820 acquires the signals (vibration signals and temperature signals, which will be described later) that have been converted into digital signals by the A / D conversion circuit AD1. Specific operations of the acquiring unit 820 will be described later.

[0106] The temperature detection unit 822 detects the temperature of the coil unit 70A based on the signal (temperature signal, which will be described later) acquired by the acquisition unit 820. The operation of the temperature detection unit 822 will be described later.

[0107] Vibration Detection Principle In the second embodiment, the first coil portion 74 and the second coil portion 75 are treated as a single coil portion 70A to detect vibrations. That is, the vibration detection portion 821 detects vibrations of the rotating shaft 32 based on the induced electromotive force generated in the coil portion 70A, as in the first embodiment. Therefore, details of the vibration detection principle in the second embodiment will be omitted.

[0108] Temperature Detection Principle Next, the temperature detection principle of the coil portion 70A in the vibration sensor unit 5A will be described. In this embodiment, the vibration sensor unit 5A detects the temperature of the coil portion 70A (i.e., the temperature of the ambient environment of the coil portion 70A) by detecting the temperatures of the first coil portion 74 and the second coil portion 75. In the following description, FIG. 9 will be referred to as appropriate.

[0109] When a direct current from the first power source 810 flows through the conductor 701, a potential difference corresponding to the resistance of the first coil portion 74 is generated between both ends of the first coil portion 74 (the lead portion 71 and the intermediate lead portion 73). Similarly, when a direct current from the second power source 811 flows through the conductor 702, a potential difference corresponding to the resistance of the second coil portion 75 is generated between both ends of the second coil portion 75 (the lead portion 72 and the intermediate lead portion 73). Here, the materials of the first coil portion 74 and the second coil portion 75 are known. Furthermore, the resistance values ​​of the first coil portion 74 and the second coil portion 75 depend on the temperatures of the first coil portion 74 and the second coil portion 75. Therefore, the temperatures of the first coil portion 74 and the second coil portion 75 can be derived from the resistance values ​​of the first coil portion 74 and the second coil portion 75. Furthermore, the current flowing through the conductors 701 and 702 is a constant current. Therefore, the resistance value of the conductor 701 (first coil portion 74) can be derived from the voltage value of the current flowing through the conductor 701 (the potential difference between both ends of the first coil portion 74). Similarly, the resistance value of the conductor 702 (second coil portion 75) can be derived from the voltage value of the current flowing through the conductor 702 (the potential difference between both ends of the second coil portion 75). Therefore, the temperature of the conductor 701 can be detected based on the potential difference between both ends of the first coil portion 74, and the temperature of the conductor 702 can be detected based on the potential difference between both ends of the second coil portion 75. In this way, the pump device 1A can detect the temperature of the coil portion 70A as well as the vibration of the rotating shaft 32 without requiring any dedicated components for detecting the temperature of the coil portion 70A. Here, the current used for temperature detection is a direct current from the power source 81A.

[0110] Operation of the pump device (2) Next, the operation of the pump device 1A will be described below, focusing on the operation of the vibration sensor unit 5A. Of the operations of the pump device 1A, the detection of vibration is the same as the operation of the pump device 1 of the first embodiment. Therefore, in the following explanation, the operation of the pump device 1A will be described, focusing on the detection of temperature. In the following explanation, Figures 6 to 9 will be referenced as appropriate.

[0111] When the pump device 1A is operating, the rotary shaft 32 rotates together with the rotor 35. The power source 81A applies a constant DC current to the conductor 7A (coil portion 70).

[0112] The voltage value of the constant current flowing through the conductor 701 (the potential difference between both ends of the first coil portion 74) is input to the non-inverting input of the operational amplifier OA2, and the voltage value of the constant current flowing through the conductor 702 (the potential difference between both ends of the second coil portion 75) is input to the inverting input of the operational amplifier OA2. The operational amplifier OA2 amplifies the difference between the two voltage values ​​(the potential difference between both ends) and outputs a signal (hereinafter referred to as the "temperature signal") indicating the difference between the potential difference between both ends of the first coil portion 74 and the potential difference between both ends of the second coil portion 75 to the A / D conversion circuit AD1. The temperature signal is converted into a digital signal by the A / D conversion circuit AD1, input to the calculation unit 82, and acquired by the acquisition unit 820.

[0113] The correlation between the difference value and the temperature is determined in advance as a table or function and stored in, for example, the ROM 82c. The temperature detection unit 822 detects the temperature of the coil unit 70A (i.e., the temperature of the ambient environment of the coil unit 70A) based on the temperature signal acquired by the acquisition unit 820 and the correlation stored in the ROM 82c. The detected temperature is stored in, for example, the memory unit 4d.

[0114] In the present invention, the arithmetic unit 82A may be provided with an information storage medium such as a flash memory, and the correlation and the detected temperature may be stored in the information storage medium.

[0115] Here, the temperature of the coil portion 70 can be detected solely from the potential difference between both ends of the first coil portion 74 or the potential difference between both ends of the second coil portion 75. That is, even if the conductor 7A is composed of a single metal wire, as with the conductor 7 of the first embodiment, the temperature of the coil portion 70A can be detected. However, the temperature change rate of metal resistance generally tends to be extremely small in extremely low temperature environments (e.g., in an environment where liquefied natural gas is being transported). Therefore, if the conductor 7A were composed of only a single metal wire, the amount of change in temperature relative to a change in resistance would be large in extremely low temperature environments, which could result in an error in the temperature detection result. Therefore, in the second embodiment, two types of metal wire are used in the coil portion 70A, and the temperature detection unit 822 utilizes the difference in the resistance values ​​of the two types of metal wire to improve the temperature detection accuracy in extremely low temperature environments.

[0116] Summary (2) According to the embodiment described above, the vibration sensor unit 5A includes a main body 6, a conductor 7A, and a vibration detection unit 821. With this configuration, similar to the vibration sensor unit 5 of the first embodiment, the vibration sensor unit 5A does not require transmission of vibrations from the rotating shaft 32 to the sensing unit itself. Therefore, the vibration sensor unit 5A is less likely to detect unintended vibrations (other than those of the rotating shaft 32), and is less likely to experience false detections due to unintended vibrations or malfunctions of the sensing unit due to vibrations. Furthermore, the sensing unit is composed only of a coil (coil unit 70A) and a yoke (main body 6). Therefore, the sensing unit can be used in a wide range of temperature environments, from extremely low to high temperatures, and is less likely to malfunction. Thus, the present invention provides a vibration sensor unit 5A that can be used in a wide temperature range and is less likely to malfunction due to vibrations and temperature.

[0117] Furthermore, according to the embodiment described above, the inner circumferential surface 61 of the main body 6 includes the first surface 66 and the end surfaces 64, 65. The end surfaces 64, 65 are arranged at positions spaced 90° apart from each other in the circumferential direction of the main body 6 (coil portion 70A). With this configuration, the vibration detection sensitivity of the vibration detection unit 821 is improved compared to the vibration detection sensitivity when the main body 6 does not include the protrusions 62, 63.

[0118] Furthermore, according to the embodiment described above, the main body 6 includes protrusions 62 and 63. The end face 64 is disposed on the protrusion 62, and the end face 65 is disposed on the protrusion 63. With this configuration, simply by forming the protrusions 62 and 63 on the inner circumferential surface 61, the vibration detection sensitivity of the vibration detection unit 821 can be easily adjusted.

[0119] Furthermore, according to the embodiment described above, the rotating shaft 32 has a rear end surface 323 that is disposed inside the main body 6. With this configuration, the vibration sensor unit 5A can also detect thrust vibrations by being configured to detect radial vibrations, similar to the vibration sensor unit 5 of the first embodiment.

[0120] Furthermore, according to the embodiment described above, the rotating shaft 32 is made of a magnetic material, and the power supply 81A is a constant current power supply circuit that supplies a constant DC current to the coil portion 70A. With this configuration, an induced electromotive force is generated in the coil portion 70A based on a change in magnetic flux, and the vibration detection portion 821 can detect the vibration of the rotating shaft 32 based on a change in the AC component of the voltage generated in the conductor 7A (coil portion 70A).

[0121] Furthermore, according to the embodiment described above, the vibration sensor unit 5A includes a temperature detection section 822 that detects the temperature of the coil section 70A based on the potential difference between both ends of the coil section 70A. With this configuration, the vibration sensor unit 5A can detect the temperature of the coil section 70A using the sensing section that detects the vibration of the rotating shaft 32.

[0122] Furthermore, according to the embodiment described above, the conductor 7A includes an intermediate lead 73, a first coil 74, and a second coil 75. The first coil 74 is a copper wire, and the second coil 75 is a nickel wire. The second coil 75 is wound in the same direction as the first coil 74 and is connected to the first coil 74 at a connection point 7P so as to be continuous with the first coil 74. The intermediate lead 73 is also connected to the connection point 7P. The temperature detection unit 822 detects the temperatures of the first coil 74 and the second coil 75 based on a signal (i.e., a temperature signal) indicating the difference between the potential difference between the ends of the first coil 74 and the potential difference between the ends of the second coil 75. This configuration improves the accuracy of temperature detection in extremely low temperature environments by utilizing the difference in the resistance values ​​of the two types of metal wire relative to temperature. As a result, the vibration sensor unit 5A can also be used to detect the temperature of the coil 70A over a wide temperature range, even in extremely low temperature environments.

[0123] Modifications Next, modifications of the pump device 1, 1A will be described below, focusing on the differences from the first and second embodiments. In the following description of the modifications, for convenience of explanation, the same components as those in the first and second embodiments and components having common functions are assigned the same reference numerals as those in the first and second embodiments, unless otherwise specified, and their description will be omitted. In the following modifications, reference will be made as appropriate to Figures 1, 2, and 6.

[0124] 10 is a circuit diagram showing a first modified example of a pump device. The same figure shows the circuit diagram of a vibration sensor unit 5B provided in a pump device 1B according to the first modified example. The pump device 1B differs from the pump device 1 of the first embodiment in the material of the rotating shaft 32, the configuration of the vibration sensor unit 5B (electronic components 80B provided in the vibration sensor unit 5B), and the power supply 81B.

[0125] In the pump device 1B, the rotating shaft 32 is made of a conductive non-magnetic material. The vibration sensor unit 5B includes, as electronic components 80B, a voltage doubler circuit composed of two capacitors C3 and C4 and two diodes D1 and D2, and a capacitor C5 connected between a power supply 81B and terminal T1. On a circuit board 8B, the electronic components 80B, the power supply 81B, terminals T1 and T2, and the operational amplifier OA1 are connected via corresponding contacts P21 to P27. Specifically, the voltage doubler circuit is mounted on the circuit board 8B and connected between the power supply 81B and the operational amplifier OA1 via contacts P21, P22, P25, and P26. In the voltage doubler circuit, diode D1 is connected to contacts P23 and P24, diode D2 is connected to contacts P23 and P25, capacitor C3 is connected to contacts P21 and P23, and capacitor C4 is connected to contacts P25 and P26. The non-inverting input of the operational amplifier OA1 is connected to terminal T1, and the inverting input is connected to terminal T2 via contact P27 and grounded. One end of a power supply 81B is connected between terminal T1 and the non-inverting input via contact P21 and capacitor C5. The other end of the power supply 81B is connected between terminal T2 and the inverting input via contact P22. The power supply 81B is a constant-current power supply circuit that supplies a constant AC current to the conductor 7. In this configuration, the constant current flowing through the coil 70 generates eddy currents in the rotating shaft 32. As a result, an induced electromotive force is generated in the coil 70 based on changes in the distance between the rotating shaft 32 and the main body 6 (protrusions 62 and 63). The magnitude of the induced electromotive force is proportional to the size of the gaps G1 and G2. In this way, the vibration sensor unit 5B detects changes in magnetic flux corresponding to vibration and can detect vibration of the rotating shaft 32 based on these changes. The voltage of the signal generated in the coil 70 is rectified and doubled by the voltage doubler circuit. As a result, the accuracy with which the vibration sensor unit 5B detects the vibration of the rotary shaft 32 is improved.

[0126] 11 is a schematic cross-sectional view showing a second modified example of a pump device. This figure shows a schematic cross-sectional view similar to FIG. 3 of a portion (main body 6 and conductor 7) of the vibration sensor unit 5C included in a pump device 1C according to the second modified example. For ease of explanation, this figure does not show a cross-section of the rotating shaft 32C included in the pump device 1C. The shape of the rotating shaft 32C in the pump device 1C differs from that of the pump device 1 of the first embodiment.

[0127] In the pump device 1C, the rotating shaft 32C includes a small-diameter portion 324 and a large-diameter portion 325. The rear portion of the rotating shaft 32C is tapered to form the small-diameter portion 324. The portion of the rotating shaft 32C forward of the small-diameter portion 324 forms the large-diameter portion 325. The outer diameter of the small-diameter portion 324 is smaller than the outer diameter of the large-diameter portion 325. The rear end surface 326 of the large-diameter portion 325 is a ring-shaped surface parallel to the up-down and left-right directions and perpendicular to the outer peripheral surface 322 of the large-diameter portion 325. The rotating shaft 32C is inserted into the main body 6. In the front-rear direction, the rear end surface 326 of the large-diameter portion 325 is located at the center of the main body 6. The rear end surface 326 is an example of an end surface of a rotating shaft according to the present invention. In this configuration, the vibration sensor unit 5C detects thrust vibration based on the position of the rear end surface 326 instead of the rear end surface 323.

[0128] In the second modified example, since the rotating shaft 32C is inserted through the main body 6, the position of the main body 6 is not limited to the rear of the housing 31. That is, for example, the main body 6 may be housed in the housing 31. In this case, the rotating shaft 32C does not need to protrude rearward from the housing 31.

[0129] Third Modification FIG. 12 is a schematic rear view showing a third modification of the pump device. This figure shows a schematic rear view similar to FIG. 2 of a portion of the configuration (main body 6 and conductors 7) of a vibration sensor unit 5D included in a pump device 1D according to the third modification, as well as a functional block diagram of a signal processing unit. For ease of explanation, this figure also shows a rotating shaft 32D included in the pump device 1D. FIG. 13 is a schematic cross-sectional view of the main body 6 and conductors 7 taken along line E-E in FIG. 12. For ease of explanation, this figure also shows a cross-section of the rotating shaft 32D. The pump device 1D differs from the pump device 1 of the first embodiment in the shape of the rotating shaft 32D and the configuration of the vibration sensor unit 5D (the calculation unit 82D included in the vibration sensor unit 5D).

[0130] In the pump device 1D, the rotating shaft 32D has multiple recesses 327 (three in the third modified example). In the radial direction of the rotating shaft 32D, a portion of the rear end 321 of the outer circumferential surface 322 of the rotating shaft 32D is recessed inward to form the recesses 327. The recesses 327 are rectangular grooves extending along the axial direction of the rotating shaft 32D. The recesses 327 are arranged at equal angular intervals (at 120° intervals in the third modified example) around the circumference of the rotating shaft 32D. The recesses 327 are arranged inside the main body 6. The recesses 327 are an example of a shaft recess defined in the present invention. The computing unit 82D includes a rotation speed detection unit 823. The rotation speed detection unit 823 detects the rotation speed of the rotating shaft 32D based on the fluctuations in voltage of the periodic induced electromotive force generated in the coil unit 70 when each recess 327 periodically approaches the protrusions 62, 63 as the rotating shaft 32D rotates. In this configuration, the vibration sensor unit 5D can detect the number of rotations as well as the vibration of the rotating shaft 32D without requiring any dedicated parts for detecting the number of rotations.

[0131] In the third modified example, the rotating shaft 32D may have a protrusion protruding radially outward from the rotating shaft 32D instead of the recess 327. In this case, the shape of the protrusion is, for example, a rectangular parallelepiped obtained by inverting the recess 327. The protrusion is an example of a shaft protrusion according to the present invention.

[0132] In the third modified example, the number of recesses 327 may be the same as the number of protrusions 62 and 63 .

[0133] 14 is a circuit diagram showing a fourth modified example of a pump device. The figure shows a circuit diagram of a vibration sensor unit 5E provided in a pump device 1E according to the fourth modified example. The pump device 1E differs from the pump device 1 of the first embodiment in that the vibration sensor unit 5E is configured to detect the temperature of the coil portion 70.

[0134] In the pump device 1E, the vibration sensor unit 5E includes a resistor R1 and an operational amplifier OA2 as electronic components 80E mounted on a circuit board 8E, as well as an arithmetic unit 82E. One end of a power supply 81 is connected to terminal T1, the non-inverting input of operational amplifier OA1, and the non-inverting input of operational amplifier OA2 via contact P31. The other end of the power supply 81 is connected to terminal T2 via contact P32 and is also grounded. A capacitor C1 is connected between the non-inverting input of operational amplifier OA1 and the non-inverting input of operational amplifier OA2 via contacts P33 and P34. One end of the resistor R1 is connected between capacitor C1 and the non-inverting input of operational amplifier OA1 via contact P34, and the other end of the resistor R2 is grounded. The inverting inputs of operational amplifiers OA1 and OA2 are grounded. The configuration of the arithmetic unit 82E is the same as that of the arithmetic unit 82A of the second embodiment. In this configuration, the vibration detection unit 821 can detect the vibration of the rotating shaft 32 based on the induced electromotive force generated in the coil portion 70, similar to the vibration sensor unit 5 of the first embodiment. Furthermore, the temperature detection unit 822 can detect the temperature of the coil portion 70 based on the potential difference between both ends of the coil portion 70, similar to the vibration sensor unit 5A. In the fourth modification, the coil portion 70 is made of a single type of metal wire. Therefore, the temperature detection accuracy of the vibration sensor unit 5E is lower than that of the vibration sensor unit 5A of the second embodiment in extremely low temperature environments, but can approximate that of the vibration sensor unit 5A in other temperature environments (especially at or above room temperature).

[0135] 15 is a schematic rear view showing a fifth modified example of a pump device. This figure shows a schematic rear view similar to that shown in FIG. 2 of a part of the configuration of a vibration sensor unit 5F (main body 6F and conductor 7) included in a pump device 1F according to the fifth modified example. In the pump device 1F, the shape of the inner circumferential surface 61 of the main body 6F differs from that of the pump device 1 of the first embodiment.

[0136] When viewed from the front-to-rear direction, a portion of the inner circumferential surface 61 (the upper end in the fifth modified example) is formed in a planar shape that describes a chord of the circle formed by the inner circumferential surface 61, forming a planar portion 67 that has the same function as the end surface 64. Another portion of the inner circumferential surface 61 (the right end in the fifth modified example) is formed in a planar shape that describes a chord of the circle formed by the inner circumferential surface 61, forming a planar portion 68 that has the same function as the end surface 65. The planar portions 67 and 68 are examples of the second surface in the present invention. In this configuration, the vibration detection unit 821 can detect vibrations of the rotating shaft 32 based on the induced electromotive force generated in the coil portion 70, similar to the vibration sensor unit 5 of the first embodiment.

[0137] 16 is a schematic rear view showing a sixth modified example of a pump device. This figure shows a schematic rear view similar to that of FIG. 2 of a part (main body 6G and conductor 7) of the configuration of a vibration sensor unit 5G provided in a pump device 1G according to the sixth modified example. The shape of the main body 6G of the pump device 1G differs from that of the pump device 1 of the first embodiment.

[0138] When viewed from the front-rear direction, a portion (the left portion in the sixth modified example) of the main body 6G is cut out along the radial direction of the main body 6G to form a cutout 69. That is, when viewed from the rear, the shape of the main body 6G is approximately C-shaped. Even with this configuration, the vibration detection unit 821 can detect vibrations of the rotating shaft 32 based on the induced electromotive force generated in the coil portion 70, similar to the vibration sensor unit 5 of the first embodiment.

[0139] 17 is a circuit diagram showing a seventh modified example of a pump device. The figure shows a circuit diagram of a vibration sensor unit 5H provided in a pump device 1H according to the seventh modified example. In the pump device 1H, the configuration of the vibration sensor unit 5H (electronic component 80H provided in the vibration sensor unit 5H) is different from that of the pump device 1A of the second embodiment.

[0140] In the pump device 1H, the vibration sensor unit 5H includes an electronic component 80H, a so-called bridge circuit using two resistors R3 and R4. The vibration sensor unit 5H also includes a single power supply 81 similar to that of the first embodiment, instead of the first power supply 810 and the second power supply 811 of the second embodiment. One end of the power supply 81 is connected to terminal T1 and the non-inverting input of the operational amplifier OA1 via contact P41, and the other end of the power supply 81 is connected to terminal T2 and the inverting input of the operational amplifier OA1 via contact P42. The resistors R3 and R4 are connected in parallel with the first coil portion 74 and the second coil portion 75 between the power supply 81 and terminals T1 and T2. Specifically, one end of the resistor R3 is connected between terminal T1 and one end of the power supply 81 via contact P43, and the other end of the resistor R3 is connected to one end of a resistor R4 via contact P44. The other end of the resistor R4 is connected between terminal T2 and the other end of the power supply 81 via contact P45. A contact P44 between the other end of resistor R3 and one end of resistor R4 is connected to the non-inverting input of operational amplifier OA2. Terminal T3 is connected to the inverting input of operational amplifier OA2. One end of resistor R1 is connected between capacitor C1 and the non-inverting input of operational amplifier OA1 via contact P46. One end of resistor R2 is connected between capacitor C2 and the inverting input of operational amplifier OA1 via contact P47. The other ends of resistors R1 and R2 are grounded via contact P48. In this configuration, operational amplifier OA2 outputs a signal indicating the ratio of the potential difference between both ends of first coil portion 74 and the potential difference between both ends of second coil portion 75 to the A / D conversion circuit AD1 as a temperature signal. The temperature signal is converted into a digital signal by the A / D conversion circuit AD1, input to the calculation unit 82A, and acquired by the acquisition unit 820.

[0141] The correlation between the ratio of the potential differences and the temperature is determined in advance as a table or a function and stored in, for example, the ROM 82c. The temperature detection unit 822 detects the temperature of the coil unit 70A based on the temperature signal acquired by the acquisition unit 820 and the correlation stored in the ROM 82c. The detected temperature is stored in, for example, the memory unit 4d.

[0142] 18 is a functional block diagram showing an eighth modified example of a pump device. The figure shows a functional block diagram of a part of the configuration of a vibration sensor unit 5J provided in a pump device 1J according to the eighth modified example. The pump device 1J differs from the pump device 1 of the first embodiment in that the vibration sensor unit 5J estimates the vibration of the rotating shaft 32 using a learning model M.

[0143] The ROM 82c of the arithmetic unit 82J mounted on the circuit board 8J of the vibration sensor unit 5J stores a learning model M and an estimation program for estimating the amount of change in vibration of the rotating shaft 32 using the learning model M. The "learning model M" is a machine-learned learning model that has been trained in advance using, for example, a known machine learning algorithm (e.g., a neural network) with the voltage change rate over a predetermined period obtained from the vibration signal output from the A / D conversion circuit AD1 as input data and the vibration displacement of the rotating shaft 32 as output data (teacher data). In other words, the learning model M has been trained to output the vibration displacement of the rotating shaft 32 when the voltage change rate is input. The vibration detection unit 821 acquires the voltage change rate based on the vibration signal over a predetermined period and estimates the amount of change in vibration of the rotating shaft 32 using the learning model M. In this way, the estimation program runs in the arithmetic unit 82J, and the estimation program works in cooperation with the hardware resources of the vibration sensor unit 5J to estimate the amount of change in vibration of the rotating shaft 32. Furthermore, by having a processor (CPU 82a) constituting the arithmetic unit 82J execute an estimation program, the estimation program can cause the processor to function as an acquisition unit 820 and a vibration detection unit 821, and can cause the processor to execute a vibration estimation method. Similarly, by having a computer execute the estimation program, the estimation program can cause the computer to function as the arithmetic unit 82J. With this configuration, the vibration sensor unit 5J can easily estimate the amount of vibration displacement of the rotating shaft 32 without requiring complex calculations.

[0144] In the eighth modified example, the vibration detection unit 821 may estimate the amount of wear of the rotating shaft 32 using the learning model M. In this case, the learning model M is machine-learned using the amount of wear of the rotating shaft 32 as output data.

[0145] In the eighth modified example, the vibration sensor unit 5J may be provided with a separate learning model storage unit that stores the learning model M. The learning model storage unit is, for example, an information storage medium such as a flash memory.

[0146] Other Embodiments The configurations of the above-described embodiments and modifications may be combined with each other.

[0147] In the above-described embodiments, the main component of the conductive wires 7, 7A is not limited to copper or nickel.

[0148] Furthermore, in each of the embodiments described above, the main body 6 (outer peripheral surface 60, inner peripheral surface 61, inscribed circle IC1) only needs to be spaced apart from the rotating shaft 32 (outer peripheral surface 322) disposed inside the main body 6, and does not have to be concentric with the rotating shaft 32. That is, when viewed from the rear, the center of the rotating shaft 32 may be offset from the center of the main body 6 (outer peripheral surface 60, inner peripheral surface 61, inscribed circle IC1). Even in this configuration, the vibration detection unit 821 detects the vibration of the rotating shaft 32 based on the induced electromotive force generated by the vibration of the rotating shaft 32, and therefore the influence on the detection of vibration by the vibration detection unit 821 is small.

[0149] Furthermore, in each of the above-described embodiments, the main body 6 may include three or more protrusions. That is, for example, the main body 6 may include three protrusions arranged at equal angular intervals (120°) in the circumferential direction of the main body 6.

[0150] Furthermore, in each of the embodiments described above, the position of the protrusion 63 does not have to be a position where the induced electromotive force due to the vibration of the rotating shaft 32 is canceled (a position rotated 180° from the protrusion 62 in the circumferential direction of the main body 6 or its vicinity), and is not limited to a position rotated 90° from the protrusion 62.

[0151] Furthermore, in each of the embodiments described above, the position of the protrusion 62 is not limited to the upper end of the inner circumferential surface 61 , and the position of the protrusion 63 is not limited to the right end of the inner circumferential surface 61 .

[0152] Furthermore, in each of the above-described embodiments, the shape of the end faces 64, 65 is not limited to being flat. That is, for example, the shape of the end faces 64, 65 may be an arc shape concentric with the inner circumferential surface 61 when viewed from the rear.

[0153] Furthermore, in each of the above-described embodiments, the main body 6 does not have to be completely annular. That is, for example, the main body 6 may have a partially cut-out shape (e.g., a C-shape) like the main body 6G in the sixth modified example. Also, for example, the main body 6 may have a shape including either the flat surface 67 or 68 in the seventh modified example (e.g., a shape in which the inner circumferential surface 61 is substantially D-shaped).

[0154] Furthermore, in each of the above-described embodiments, the main body 6 may be a seamless annular shape or a seamless annular shape, i.e., the main body 6 may be made of two semicircular annular pieces of magnetic material, for example.

[0155] Furthermore, in each of the embodiments described above, the main body 6 does not have to be provided with the protrusions 62 and 63, although this reduces the accuracy of detecting vibrations of the rotating shaft 32.

[0156] Furthermore, in each of the embodiments described above, the rotating shaft 32 may be inserted through the main body 6, and the rear end surface 323 of the rotating shaft 32 may not be located inside the main body 6. In this configuration, the vibration sensor units 5, 5A do not detect thrust vibrations. In this case, the main body 6 may be located so as to cover either one of the bearings 33, 34 in the radial direction of the rotating shaft 32, for example.

[0157] Furthermore, in each of the above-described embodiments, the rotating shaft 32 is made of a conductive magnetic material. Alternatively, the rotating shaft 32 may be made of a conductive but non-magnetic material (non-magnetic material) as shown in the first modification. In this case, the power supplies 81, 81A pass a constant AC current through the conductors 7, 7A. In this configuration, the constant current flowing through the coil portion 70 generates eddy currents in the rotating shaft 32. As a result, an induced electromotive force is generated in the coil portion 70, 70A based on changes in the distance between the rotating shaft 32 and the main body portion 6 (protrusions 62, 63). The magnitude of the induced electromotive force is proportional to the size of the gaps G1, G2. Therefore, the vibration sensor units 5, 5A can detect changes in magnetic flux corresponding to vibration and detect vibration of the rotating shaft 32 based on these changes.

[0158] Furthermore, in each of the above-described embodiments, the rotating shaft 32 may be made of a non-conductive magnetic material (e.g., ferrite). Even in this configuration, the vibration sensor unit 5, 5A can detect a change in magnetic flux in response to vibration and detect the vibration of the rotating shaft 32 based on this change.

[0159] Furthermore, in each of the embodiments described above, when the power sources 81, 81A are DC power sources, as long as at least the portion of the rotating shaft 32 located inside the main body 6 (for example, the portion protruding rearward from the rear wall 315) is made of a conductive material, the other portions may be made of an insulating material. That is, for example, the portion of the rotating shaft 32 located forward of the rear opening 311 may be made of an insulating material (for example, ceramics), and the portion protruding rearward from the rear opening 311 may be made of a conductive material.

[0160] Furthermore, in each of the embodiments described above, when the power sources 81, 81A are DC power sources, it is sufficient that the portion of the rotating shaft 32 that is located inside the main body 6 (for example, the portion that protrudes rearward from the rear wall 315) is made of a magnetic material, and the other portions may be made of a non-magnetic material. Similarly, when the power sources 81, 81A are AC power sources, it is sufficient that at least the portion of the rotating shaft 32 that is located inside the main body 6 is made of a conductive non-magnetic material, and the other portions may be made of a magnetic material.

[0161] Furthermore, in each of the embodiments described above, the inner circumferential surface 61 of the main body 6 directly faces the outer circumferential surface 322 of the rotating shaft 32. Alternatively, an object (such as the can of a canned motor pump) may be disposed between the rotating shaft 32 and the main body 6.

[0162] Furthermore, in each of the embodiments described above, the vibration sensor unit 5, 5A detects the vibration of the rotating shaft 32 of the motor section 3. Alternatively, the vibration sensor unit 5, 5A can detect the vibration of any rotating body made of a conductive material.

[0163] Furthermore, in each of the embodiments described above, the control device 4 may function as the arithmetic units 82 and 82A.

[0164] Furthermore, in each of the embodiments described above, the pump device 1, 1A includes the sensor unit 5, 5A. Alternatively, the motor section 3 may include the sensor unit 5, 5A.

[0165] Furthermore, in each of the embodiments and variants described above, the various programs may be stored in an installable file format or an executable file format on a non-temporary storage medium (e.g., a CD (Compact Disk), a DVD (Digital Versatile Disc), a USB (Universal Serial Bus) memory, etc.) and provided to the vibration sensor units 5 to 5J via a dedicated reading medium.

[0166] Embodiments of the Present Invention Next, embodiments of the present invention that can be understood from the above-described embodiments will be described below, using the terms and symbols described in the respective embodiments.

[0167] A first embodiment of the present invention is a vibration sensor unit (e.g., vibration sensor units 5 to 5J) that detects vibrations of a rotating shaft (e.g., rotating shafts 32, 32C, 32D) of a rotating electric machine (e.g., motor unit 3), and includes a conductor (e.g., conductor 7, 7A) having at least one coil portion (e.g., coil portion 70, 70A) wound in a circular coil shape, a main body portion (e.g., main body portion 6, 6F, 6G) made of a magnetic material and arranged inside the coil portion in contact with the coil portion, a power source (e.g., power sources 81, 81A, 81B, first power source 810, second power source 811) that supplies a constant current to the coil portion, and a power supply (e.g., power sources 81, 81A, 81B, first power source 810, second power source 811) that detects the vibrations based on a change in the AC component of the voltage generated in the conductor. and a vibration detection unit (e.g., vibration detection unit 821) that outputs a vibration signal, wherein the rotating shaft has a cylindrical outer peripheral surface (e.g., outer peripheral surface 60) that is aligned with the rotational direction of the rotating shaft, the main body has an annular shape that is aligned with the circumferential direction of the coil section and through which the rotating shaft can be inserted, or has a shape with a portion of the annular shape cut out, and when the rotating shaft is positioned inside the main body so as to rotate in the circumferential direction of the coil section, the portion of the rotating shaft that is positioned inside the main body is made of a material that is at least conductive or magnetic, and the inner peripheral surface (e.g., inner peripheral surface 61) of the main body is positioned at a distance from the outer peripheral surface of the rotating shaft. This configuration makes it possible to realize a vibration sensor unit that is usable over a wide temperature range and is less susceptible to failures due to vibration and temperature.

[0168] A second embodiment of the present invention is the vibration sensor unit of the first embodiment, wherein the inner circumferential surface of the main body portion includes a first surface (e.g., first surface 66) having a first radius larger than the radius of the rotation shaft, and at least one second surface (e.g., end surfaces 64, 65, flat surfaces 67, 68) whose distance from the center of curvature of the first surface is smaller than the first radius. With this configuration, the vibration detection sensitivity of the vibration detection unit is improved compared to when the main body portion does not include a protrusion.

[0169] A third aspect of the present invention is the vibration sensor unit of the second aspect, wherein the inner circumferential surface of the main body includes a plurality of second surfaces arranged at different positions in the circumferential direction of the coil portion. With this configuration, the vibration detection sensitivity of the vibration detection unit is further improved.

[0170] A fourth aspect of the present invention is the vibration sensor unit of the second aspect, wherein the main body has a protrusion (e.g., protrusions 62, 63) that protrudes inward from a part of the inner circumferential surface in the radial direction of the coil, and the second surface (e.g., end surfaces 64, 65) is disposed on the protrusion. With this configuration, the vibration detection sensitivity of the vibration detection unit can be easily improved simply by forming a protrusion on the inner circumferential surface.

[0171] A fifth aspect of the present invention is the vibration sensor unit of the first aspect, wherein the rotating shaft has an end face (e.g., rear end face 323, 326) that is parallel to the radial direction of the rotating shaft and perpendicular to the outer circumferential surface of the rotating shaft, and when the rotating shaft is arranged inside the main body so as to rotate in the circumferential direction of the coil section, the end face is arranged inside the main body. With this configuration, the vibration sensor unit can detect thrust vibrations as well as radial vibrations.

[0172] A sixth aspect of the present invention is a vibration sensor unit (e.g., vibration sensor unit 5D) in the first aspect, in which the rotating shaft (e.g., rotating shaft 32D) has a shaft protrusion (e.g., convex portion) in which a part of the outer circumferential surface protrudes outward in the radial direction of the rotating shaft, or a shaft recess (e.g., recess 327) that is recessed inward, and when the rotating shaft is arranged inside the main body so as to rotate in the circumferential direction of the coil section, the shaft protrusion or the shaft recess is arranged inside the main body. With this configuration, the vibration sensor unit can detect the rotation speed as well as the vibration of the rotating shaft without requiring any dedicated parts necessary for detecting the rotation speed.

[0173] A seventh aspect of the present invention is a vibration sensor unit according to the first aspect, wherein the power source is a DC power source (e.g., power source 81, 81A, first power source 810, second power source 811) that supplies the constant DC current to the coil when the portion of the rotating shaft disposed inside the main body is made of a magnetic material, and an AC power source (e.g., power source 81B) that supplies the constant AC current to the coil when the portion of the rotating shaft disposed inside the main body is made of a conductive non-magnetic material. With this configuration, a magnetic field can be easily formed around the coil. Eddy currents are also generated in the rotating shaft made of a non-magnetic material. As a result, the vibration sensor unit can detect changes in magnetic flux in response to vibration.

[0174] An eighth aspect of the present invention is a vibration sensor unit (e.g., vibration sensor units 5A, 5E, 5H) according to any one of the first to seventh aspects, which includes a temperature detection unit (e.g., temperature detection unit 822) that detects the temperature of the coil portion based on the potential difference between both ends of the coil portion. According to this configuration, the vibration sensor unit can detect the temperature of the coil portion using a sensing unit that detects vibrations of the rotating shaft.

[0175] A ninth embodiment of the present invention is a vibration sensor unit (e.g., vibration sensor units 5A and 5H) in the eighth embodiment, wherein the conductor (e.g., conductor 7A) comprises two coil portions and intermediate lead-out portions (e.g., intermediate lead-out portion 73) connected to each of the two coil portions, one of the two coil portions is a first coil portion (e.g., first coil portion 74) containing a first metal as a main component, and the other of the two coil portions is a second coil portion (e.g., second coil portion 75) containing a second metal different from the first metal as a main component, the second coil portion being wound in the same direction as the first coil portion in the circumferential direction of the coil portions and connected to the first coil portion at a connection point (e.g., connection point 7P) so as to be continuous with the first coil portion, the intermediate lead-out portion being connected to the connection point, and the temperature detection unit detects the temperature of the two coil portions based on the potential difference between both ends of the first coil portion and the potential difference between both ends of the second coil portion. According to this configuration, the vibration sensor unit can also be used to detect the temperature of the coil portion over a wide temperature range, even in extremely low temperature environments.

[0176] A tenth aspect of the present invention is a vibration sensor unit (e.g., vibration sensor unit 5J) according to the first aspect, which includes an acquisition unit (e.g., acquisition unit 820) that acquires a signal (e.g., a vibration signal) including the AC component, and a memory unit (e.g., ROM 82c) that stores a learning model (e.g., learning model M) that has been machine-learned to output a displacement amount of the vibration when a rate of change of voltage acquired based on a change in the AC component is input, and the vibration detection unit acquires the rate of change based on the signal indicating the change in the AC component, inputs the acquired rate of change into the learning model, and estimates the displacement amount. With this configuration, the vibration sensor unit can easily estimate the displacement amount of the vibration of the rotating shaft.

[0177] An eleventh aspect of the present invention comprises a rotor (e.g., rotor 35), a stator (e.g., stator 36) that houses the rotor and rotates the rotor, a rotating shaft (e.g., rotating shafts 32, 32C, 32D) that rotates together with the rotor, bearings (e.g., bearings 33, 34) that support the rotating shaft, and a vibration sensor unit (e.g., vibration sensor units 5 to 5J) that detects vibrations of the rotating shaft, wherein the vibration sensor unit comprises a conductor (e.g., conductor 7, 7A) having a coil portion (e.g., coil portion 70) wound in a circular coil shape, a main body portion (e.g., main body portions 6, 6F, 6G) made of a magnetic material that is arranged inside the coil portion in contact with the coil portion, and a power source (e.g., power source 8) that supplies a constant current to the coil portion. a vibration detection unit (e.g., vibration detection unit 821) that detects the vibration based on a change in the AC component of the voltage generated in the conductor, the main body having an annular shape along the circumferential direction of the coil, or a shape with a portion of the annular shape cut out, the rotating shaft disposed inside the main body so as to rotate in the circumferential direction of the coil, and having a cylindrical outer peripheral surface (e.g., outer peripheral surface 322) along the rotational direction of the rotating shaft, the portion of the rotating shaft disposed inside the main body being made of at least a conductive or magnetic material, and the inner peripheral surface of the main body being spaced apart from the outer peripheral surface of the rotating shaft. This configuration realizes a rotating electric machine equipped with a vibration sensor unit that is usable over a wide temperature range and is less susceptible to failures due to vibration and temperature.

[0178] A twelfth embodiment of the present invention is a pump device (e.g., pump devices 1 to 1J) including an impeller (e.g., impeller 26) and the rotating electric machine (e.g., motor unit 3) according to the eleventh embodiment that rotates the impeller. This configuration makes it possible to realize a pump device equipped with a vibration sensor unit that can be used over a wide temperature range and is less susceptible to failures caused by vibration and temperature.

[0179] DESCRIPTION OF SYMBOLS 1 Pump device 3 Motor section (rotating electric machine) 32 Rotating shaft 321 Rear end section 322 Outer peripheral surface 323 Rear end surface (end surface) 5 Vibration sensor unit 6 Main body section 60 Outer peripheral surface 61 Inner peripheral surface 62 Protruding section 63 Protruding section 64 End surface (second surface) 65 End surface (second surface) 66 First surface 7 Conducting wire 70 Coil section 81 Power supply 821 Vibration detection section 1A Pump device 5A Vibration sensor unit 7A Conducting wire 73 Intermediate lead-out section 74 First coil section 75 Second coil section 810 First power supply (power supply) 811 Second power supply (power supply) 822 Temperature detection section 1B Pump device 5B Vibration sensor unit 81B Power supply 1C Pump device 32C Rotating shaft 326 Rear end surface (end surface) 1D Pump device 32D Rotating shaft 327 Recess (shaft recess) 5D Vibration sensor unit 823 Rotation speed detection section 1E Pump device 5E Vibration sensor unit 1F Pump device 6F Main body section 67 Flat surface section (second surface) 68 Flat surface section (second surface) 1G Pump device 6G Main body section 69 Notch section 1H Pump device 5H Vibration sensor unit 1J Pump device 5J Vibration sensor unit

Claims

1. A vibration sensor unit for detecting vibrations of a rotating shaft of a rotating electric machine, comprising: a conductor having at least one coil portion wound into a circular coil; a main body portion made of a magnetic material arranged inside the coil portion in contact with the coil portion; a power source for passing a constant current through the coil portion; and a vibration detection portion for detecting the vibrations based on changes in the AC component of the voltage generated in the conductor; wherein the rotating shaft has a cylindrical outer peripheral surface that follows the rotation direction of the rotating shaft, and the main body portion has an annular shape that follows the circumferential direction of the coil portion and through which the rotating shaft can be inserted, or has a shape with a portion of the annular shape cut out, and when the rotating shaft is arranged inside the main body portion so as to rotate in the circumferential direction of the coil portion, the portion of the rotating shaft that is arranged inside the main body portion is made of a material that is at least conductive or magnetic, and the inner peripheral surface of the main body portion is arranged at a distance from the outer peripheral surface of the rotating shaft.

2. A vibration sensor unit as described in claim 1, wherein the inner circumferential surface of the main body portion comprises: a first surface having a first radius larger than the radius of the rotation axis; and at least one second surface, the distance from the center of curvature of the first surface being smaller than the first radius.

3. A vibration sensor unit as described in claim 2, wherein the inner circumferential surface of the main body portion is provided with a plurality of second surfaces arranged at different positions in the circumferential direction of the coil portion.

4. A vibration sensor unit as described in claim 2, wherein the main body portion has a protrusion in which a part of the inner circumferential surface protrudes inward in the radial direction of the coil portion, and the second surface is positioned on the protrusion.

5. The vibration sensor unit described in claim 1, wherein the rotating shaft has an end face that is parallel to the radial direction of the rotating shaft and perpendicular to the outer peripheral surface of the rotating shaft, and when the rotating shaft is positioned inside the main body portion so as to rotate in the circumferential direction of the coil portion, the end face is positioned inside the main body portion.

6. The vibration sensor unit described in claim 1, wherein the rotating shaft has a shaft protruding portion in which a portion of the outer circumferential surface protrudes outward in the radial direction of the rotating shaft, or a shaft recessed portion in which a portion of the outer circumferential surface protrudes inward, and when the rotating shaft is positioned inside the main body portion so as to rotate in the circumferential direction of the coil portion, the shaft protruding portion or the shaft recessed portion is positioned inside the main body portion.

7. A vibration sensor unit as described in claim 1, wherein the power supply is a DC power supply that supplies the constant DC current to the coil section when the portion of the rotating shaft that is arranged inside the main body section is made of a magnetic material, and an AC power supply that supplies the constant AC current to the coil section when the portion of the rotating shaft that is arranged inside the main body section is made of a conductive non-magnetic material.

8. A vibration sensor unit according to any one of claims 1 to 7, further comprising: a temperature detection section that detects the temperature of said coil section based on a potential difference between both ends of said coil section.

9. A vibration sensor unit as described in claim 8, wherein the conductor comprises: two coil portions; and an intermediate lead-out portion connected to each of the two coil portions; one of the two coil portions is a first coil portion containing a first metal as a main component, and the other of the two coil portions is a second coil portion containing a second metal different from the first metal as a main component; in the circumferential direction of the coil portions, the second coil portion is wound in the same direction as the first coil portion and is connected at a connection point so as to be continuous with the first coil portion; the intermediate lead-out portion is connected to the connection point; and the temperature detection portion detects the temperature of the two coil portions based on the potential difference between both ends of the first coil portion and the potential difference between both ends of the second coil portion.

10. A vibration sensor unit as described in claim 1, comprising: an acquisition unit that acquires a signal including an AC component; and a memory unit that stores a learning model that has been machine-learned to output a displacement amount of the vibration when a rate of change in voltage acquired based on the change in the AC component is input, wherein the vibration detection unit acquires the rate of change based on a signal indicating the change in the AC component, and inputs the acquired rate of change into the learning model to estimate the displacement amount.

11. A sensor comprising: a rotor; a stator that houses the rotor and rotates the rotor; a rotating shaft that rotates together with the rotor; a bearing that supports the rotating shaft; and a vibration sensor unit that detects vibration of the rotating shaft, the vibration sensor unit comprising: a conductor having a coil portion wound in a circular coil shape; a main body portion made of a magnetic material that is arranged inside the coil portion and in contact with the coil portion; a power source that flows a constant current into the coil portion; and a vibration detection portion that detects the vibration based on a change in the AC component of the voltage generated in the conductor; the main body portion is annular along the circumferential direction of the coil portion, through which the rotating shaft can be inserted, or has a shape with a portion of the annular shape cut out; the rotating shaft is arranged inside the main body portion so as to rotate in the circumferential direction of the coil portion, and has a cylindrical outer circumferential surface that follows the rotation direction of the rotating shaft; the portion of the rotating shaft that is arranged inside the main body portion is made of a material that is at least conductive or magnetic, and the inner circumferential surface of the main body portion is arranged spaced apart from the outer circumferential surface of the rotating shaft. Rotating electric motor.

12. A pump device comprising: an impeller; and a rotating electric machine according to claim 11 that rotates the impeller.

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