Vibration monitoring device, supercharger, and vibration monitoring method

Abstract

This vibration monitoring device for monitoring vibrations of a rotating body that includes an impeller portion of a rotating machine comprises: a rotation sensor which is disposed at a distance in the radial direction from the impeller portion, outputs a rotation signal synchronized with the rotation of the rotating body, and is configured such that the output of the rotation signal changes in accordance with the distance between the impeller portion and the rotation sensor; a segment acquiring unit which acquires a plurality of segments of the rotation signal in which the output exceeds a predetermined threshold; and a vibration signal acquiring unit which detects a peak value from each of the plurality of segments and acquires a vibration signal, which is a signal that is based on changes in the peak value and that relates to vibration of the impeller portion.

Description

Vibration monitoring device, turbocharger, and vibration monitoring method

[0001] The present disclosure relates to a vibration monitoring device for monitoring vibration of a rotating body of a rotary machine, a turbocharger including the vibration monitoring device, and a vibration monitoring method.This application claims priority based on Japanese Patent Application No. 2023-156326, filed with the Japan Patent Office on September 21, 2023, the contents of which are incorporated herein by reference.

[0002] A rotary machine such as a turbomachine is provided with an impeller that rotates integrally with a rotor. This impeller has a plurality of blades and is housed in a casing (see, for example, Patent Document 1). Patent Document 1 discloses an invention that uses a rotation sensor disposed on the outer periphery of the impeller (the impeller of a centrifugal compressor) via a clearance to acquire the rotation speed, vibration, and clearance of the impeller (rotating body).

[0003] Japanese Patent Application Laid-Open No. 2013-224847

[0004] In the invention described in Patent Document 1, when detecting a peak value from the output of the rotation sensor at which the clearance between the rotation sensor and the impeller is minimal, using an analog circuit may result in poor detection accuracy. Furthermore, when digitally processing the output from the rotation sensor using a computer such as an electronic control device, the output from the rotation sensor is stored in a memory unit as time-series data, and peak values ​​are detected from the time-series data to detect a vibration waveform. Because the detection of the peak values ​​and vibration waveforms depends on the signal processing (processing speed) of the electronic control device, equipment with relatively high computing power is required, which increases the cost of the monitoring device itself.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a vibration monitoring device that can accurately acquire vibration components of a rotating body of a rotary machine without using equipment with high computing power, a turbocharger equipped with the vibration monitoring device, and a vibration monitoring method.

[0006] A vibration monitoring device according to at least one embodiment of the present disclosure is a vibration monitoring device for monitoring vibrations of a rotating body including an impeller section of a rotary machine, and comprises: a rotation sensor arranged at a radial distance from the impeller section, which outputs a rotation signal synchronized with the rotation of the rotating body and is configured so that the output of the rotation signal changes depending on the distance between the impeller section and the rotation sensor; a segment acquisition unit that acquires multiple segments of the rotation signal whose output exceeds a predetermined threshold; and a vibration signal acquisition unit that detects peak values ​​from each of the multiple segments and acquires a vibration signal that is a signal related to the vibration of the impeller section based on changes in the peak values.

[0007] A turbocharger according to at least one embodiment of the present disclosure includes the vibration monitoring device, a compressor including the impeller portion provided at one end of the rotor, and a turbine provided at the other end of the rotor.

[0008] A vibration monitoring method according to at least one embodiment of the present disclosure is a vibration monitoring method for monitoring vibrations of a rotating body including an impeller section of a rotary machine, and includes: a rotation signal output step of causing a rotation sensor arranged radially spaced apart from the impeller section to output a rotation signal synchronized with the rotation of the rotating body, the rotation signal having an output that changes according to the distance between the impeller section and the rotation sensor; a segment acquisition step of acquiring multiple segments of the rotation signal whose output exceeds a predetermined threshold; and a vibration signal acquisition step of detecting peak values ​​from each of the multiple segments and acquiring a vibration signal that is a signal related to the vibration of the impeller section based on changes in the peak values.

[0009] According to at least one embodiment of the present disclosure, there are provided a vibration monitoring device that can accurately acquire vibration components of a rotating body of a rotary machine without using equipment with high computing power, a turbocharger that includes the vibration monitoring device, and a vibration monitoring method.

[0010] FIG. 1 is a diagram schematically illustrating a configuration of a rotating machine equipped with a vibration monitoring device according to an embodiment of the present disclosure. FIG. 2 is an explanatory diagram illustrating the arrangement of a rotation sensor according to an embodiment of the present disclosure. FIG. 3 is an explanatory diagram illustrating the output of a rotation sensor according to an embodiment of the present disclosure. FIG. 4 is an explanatory diagram illustrating a plurality of segments according to an embodiment of the present disclosure. FIG. 5 is an explanatory diagram illustrating a vibration signal according to an embodiment of the present disclosure. FIG. 6 is an explanatory diagram illustrating a pulse signal and a rotation pulse signal according to an embodiment of the present disclosure. A diagram illustrating the amplitude-frequency characteristics of a bandpass filter. FIG. 7 is a flow chart illustrating an example of a vibration monitoring method according to an embodiment of the present disclosure.

[0011] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure.

[0012] (Rotating Machine) Fig. 1 is a diagram schematically illustrating the configuration of a rotating machine 2 equipped with a vibration monitoring device 1 according to an embodiment of the present disclosure. The vibration monitoring device 1 and vibration monitoring method according to some embodiments are each intended to monitor vibrations of a rotating body 21 of the rotating machine 2. The rotating machine 2 is configured so that the rotating body 21 can rotate about a central axis CA. The rotating machine 2 includes the rotating body 21, a bearing 22 that rotatably supports the rotating body 21, and a casing 23 that houses the rotating body 21 and the bearing 22. The bearing 22 is supported by the casing 23. The casing 23 is configured to remain stationary (not rotate) even when the rotating body 21 rotates.

[0013] In the following embodiments, a turbocharger 2A, more specifically, an exhaust turbocharger that is mounted on a ship and that supercharges the intake air of the engine, will be described as an example of the rotary machine 2. Note that the vibration monitoring device 1 and vibration monitoring method according to the present disclosure can also be applied to turbochargers 2A other than exhaust turbochargers and rotary machines 2 other than the turbocharger 2A. An example of a rotary machine 2 other than the turbocharger 2A is an electric compressor that is configured to be driven by an electric motor.

[0014] Hereinafter, the direction in which the central axis CA of the rotating body 21 extends is defined as the axial direction of the rotating body 21 (rotating machine 2), the direction perpendicular to the central axis CA is defined as the radial direction of the rotating body 21 (rotating machine 2), and the circumferential direction around the central axis CA is defined as the circumferential direction of the rotating body 21 (rotating machine 2). Hereinafter, the axial direction, radial direction, and circumferential direction of the rotating body 21 (rotating machine 2) may be simply referred to as the axial direction, radial direction, and circumferential direction.

[0015] The rotating body 21 includes a rotating shaft 24 extending along a central axis CA and an impeller unit 25 attached to the rotating shaft 24. In the illustrated embodiment, the rotating body 21 of the turbocharger 2A includes the rotating shaft 24, a compressor 25A, and a turbine 25B. The compressor 25A is configured to compress intake air (e.g., air) guided to an engine (not shown). The turbine 25B is configured to be driven by energy of exhaust gas discharged from the engine (not shown). Note that, although the compressor 25A is configured as the impeller unit 25 in the illustrated embodiment, the turbine 25B may also be configured as the impeller unit 25.

[0016] The compressor 25A is provided on one axial side (left side in FIG. 1 ) of the rotating shaft 24, and the turbine 25B is provided on the other axial side (right side in FIG. 1 ) of the rotating shaft 24. The rotating shaft 24 coaxially connects the compressor 25A and the turbine 25B. The rotating shaft 24 is rotatably supported by a bearing 22 between the compressor 25A and the turbine 25B in the axial direction. With the rotating shaft 24 rotatably supported by the bearing 22, the rotating body 21 is rotatable about the central axis CA.

[0017] When the exhaust gas passes through the turbine 25B, the turbine 25B converts the energy of the exhaust gas into rotational energy of the turbine 25B. The rotating shaft 24 and the compressor 25A connected to the turbine 25B rotate about the central axis CA together with the rotation of the turbine 25B.

[0018] (Impeller Section) FIG. 2 is an explanatory diagram illustrating the arrangement of the rotation sensor 3 according to an embodiment of the present disclosure. The symbol R in FIG. 2 indicates the rotation direction of the impeller section 25. As shown in FIGS. 1 and 2 , the impeller section 25 includes a hub 26 attached to the rotating shaft 24 and a plurality of blades (vanes) 27 protruding from an outer circumferential surface 261 of the hub 26. Because the hub 26 of the impeller section 25 is mechanically fixed to the rotating shaft 24, the hub 26 and the plurality of blades 27 can rotate integrally with the rotating shaft 24. The plurality of blades 27 are spaced apart from one another in the circumferential direction. Each of the plurality of blades 27 has a hub-side end 271 that is the base end of the blade 27 and is connected to the outer circumferential surface 261 of the hub 26, and a tip-side end 272 that is the tip end of the blade 27. The hub-side end 271 is an end on one side in the span direction (radially inner side) of the blade 27, and the tip-side end 272 is an end on the other side in the span direction (radially outer side) of the blade 27. The span direction is a direction connecting the hub-side end 271 and the tip-side end 272 at each dimensionless meridian plane length position.

[0019] In the illustrated embodiment, the compressor 25A is a centrifugal compressor configured to guide intake air introduced from the one axial side to the outside in the radial direction. The outer peripheral surface 261 of the hub 26 is formed in a concave curved shape such that the distance from the central axis CA increases from the one axial side to the other axial side.

[0020] (Rotation Sensor) As shown in FIGS. 1 and 2 , the rotation sensor 3 is disposed with a radial gap (clearance) between it and the impeller portion 25. The rotation sensor 3 is disposed on the outer periphery of the plurality of blades 27, specifically in the range in the axial direction where the plurality of blades 27 are present. The rotation sensor 3 is fixed in position by being supported by the casing 23, for example. The rotation sensor 3 is configured to output a rotation signal A that is synchronized with the rotation of the rotor 21. The rotation sensor 3 is configured so that the output of the rotation signal A changes depending on the distance D between the impeller portion 25 and the rotation sensor 3. In the following embodiment, a case will be described in which the output (output signal) from the rotation sensor 3 is a voltage value, but the output (output signal) from the rotation sensor 3 may also be a current value.

[0021] The rotation sensor 3 may be, for example, a magnetic sensor that can detect changes in the magnetic field from the multiple blades 27, or an optical sensor that detects the distance to the multiple blades 27 by reflected light of laser light.

[0022] In one embodiment, the rotation sensor 3 is an eddy current displacement sensor configured to detect the distance to the blades 27 by generating eddy currents in the plurality of blades 27. The eddy current displacement sensor is configured with a coil that generates high-frequency magnetic flux, and detects changes in eddy currents generated in the plurality of blades 27, which are targets (objects to be measured), as changes in the impedance of the coil. In other words, the eddy current displacement sensor detects changes in the distance D associated with the rotation of the impeller portion 25 as changes in the impedance of the coil.

[0023] In one embodiment, the rotation sensor 3 is a laser displacement sensor that has a laser head that emits laser light, and that emits the laser light from the laser head to a plurality of blades 27 and detects the distance from the laser head to the blades 27 based on the reflected light of the laser light.

[0024] 3 is an explanatory diagram illustrating the output of the rotation sensor 3 according to an embodiment of the present disclosure. In FIG. 3, the output waveform of the rotation sensor 3 is shown in a graph with time on the horizontal axis and the output (e.g., voltage value) of the rotation sensor 3 on the vertical axis. The output (output signal) from the rotation sensor 3 is synchronized with the rotation of the impeller unit 25. During one rotation of the impeller unit 25, an output corresponding to the distance D between each of the plurality of blades 27 and the rotation sensor 3 is obtained from the rotation sensor 3.

[0025] In the embodiment shown in FIGS. 2 and 3, the impeller unit 25 includes eleven blades 27. Reference symbols N1 to N11 in FIGS. 2 and 3 indicate the positions of the plurality of blades 27 at which the distance from the rotation sensor 3 is smallest. These positions N1 to N11 are located on the tip-side end 272. It is preferable that these positions N1 to N11 have the same or approximately the same radial distance from the central axis CA. Here, "approximately the same radial distance from the central axis CA" means that, when the radial distance D1 from the central axis CA of any one of the positions N1 to N11 is defined as D1, and the radial distance D2 from the central axis CA of any other of the positions N1 to N11 is defined as D2, the following condition is satisfied: 0.95D1≦D2≦1.05D1.

[0026] 3, the rotation sensor 3 is configured so that the output (voltage value) of the rotation sensor 3 increases as the distance D between the plurality of blades 27 and the rotation sensor 3 decreases. The tip end 272 of each of the plurality of blades 27 is closest to the rotation sensor 3. As a result, the rotation sensor 3 is able to obtain a peak value (maximum value) of output (voltage value) at the tip end 272 of each of the plurality of blades 27. As a result, during one rotation of the impeller portion 25, the rotation sensor 3 is able to obtain as many peak values ​​(maximum values) as there are blades 27.

[0027] As shown in FIG. 1 , a vibration monitoring device 1 according to some embodiments includes at least the rotation sensor 3, a segment acquisition unit 4, and a vibration signal acquisition unit 5. The segment acquisition unit 4 is electrically connected to the rotation sensor 3 and is capable of acquiring a rotation signal A, which is an output value of the rotation sensor 3. In the illustrated embodiment, the segment acquisition unit 4 and the vibration signal acquisition unit 5 are each configured using analog circuits that can be manufactured relatively inexpensively. The segment acquisition unit 4 and the vibration signal acquisition unit 5 may each be configured using a computer such as an electronic control device. This computer includes a processor such as a CPU or GPU, memory such as a ROM or RAM, and an I / O interface (not shown). The segment acquisition unit 4 and the vibration signal acquisition unit 5, which are configured using a computer, realize their respective functional units by the processor operating (e.g., performing calculations) according to instructions from a program loaded into the memory. The segment acquisition unit 4 and the vibration signal acquisition unit 5 may also be functional units included in a single electronic control device.

[0028] (Segment Acquisition Unit) FIG. 4 is an explanatory diagram illustrating multiple segments S according to an embodiment of the present disclosure. In FIG. 4, the output waveform (signal waveform) of the segment acquisition unit 4 is shown in a graph with time on the horizontal axis and the output (e.g., voltage value) of the segment acquisition unit 4 on the vertical axis. The segment acquisition unit 4 is configured to acquire multiple segments S (S1 to S11) of the rotation signal A output from the rotation sensor 3, the output of which exceeds a predetermined threshold value TL. If the output (output signal) from the rotation sensor 3 is a voltage value, it is preferable that the threshold value TL is also a voltage value. Furthermore, if the output (output signal) from the rotation sensor 3 is a current value, it is preferable that the threshold value TL is also a current value.

[0029] The segment acquisition unit 4 starts acquiring the rotation signal A when the rotation signal A output from the rotation sensor 3 exceeds a predetermined threshold TL. The segment acquisition unit 4 then continues acquiring the rotation signal A until the rotation signal A output from the rotation sensor 3 exceeds a peak value (maximum value) and decreases to the predetermined threshold TL. Each of the multiple segments S (S1 to S11) is the rotation signal A from the start point to the end point where the rotation signal A decreases to the predetermined threshold TL.

[0030] The segment acquisition unit 4 does not need to acquire the rotation signal A during the period between each of the multiple segments S (S1 to S11), i.e., during the period when the rotation signal A output from the rotation sensor 3 is equal to or less than a predetermined threshold value TL. The segment acquisition unit 4 may output a preset value (e.g., zero voltage) or may cut off output during the period between each of the multiple segments S (S1 to S11). The vibration signal acquisition unit 5 is electrically connected to the segment acquisition unit 4 and is capable of acquiring the output value of the segment acquisition unit 4. The output of the segment acquisition unit 4 includes the multiple segments S (S1 to S11).

[0031] (Vibration Signal Acquisition Unit) FIG. 5 is an explanatory diagram illustrating a vibration signal according to one embodiment of the present disclosure. In FIG. 5, a signal waveform acquired from the vibration signal C is shown in a graph with time on the horizontal axis and the vibration signal C, which is the output of the vibration signal acquisition unit 5, on the vertical axis. The vibration signal C includes information on the amplitude AP (see FIG. 4) of the vibration signal C. The vibration signal acquisition unit 5 is configured to detect peak values ​​PV (PV1 to PV11) from each of the multiple segments S (S1 to S11) acquired by the segment acquisition unit 4 described above. The vibration signal acquisition unit 5 is then configured to acquire a vibration signal C based on changes in the multiple peak values ​​PV (PV1 to PV11) detected from the multiple segments S (S1 to S11). The vibration signal C is a signal from which information on the vibration of the impeller unit 25 described above can be acquired. The vibration information may be, for example, the frequency, the magnitude, or the speed of the vibration.

[0032] According to the above configuration, peak values ​​PV (PV1 to PV11) can be detected from each of the multiple segments S (S1 to S11), and a vibration signal C corresponding to changes in the peak values ​​PV can be acquired. That is, among the time-series data of the rotation signal A, segments whose output does not satisfy the predetermined threshold value TL can be excluded from the detection target for the peak value PV, and each of the multiple segments S can be used as the detection target for the peak value PV. In this case, compared to directly detecting the peak value PV from the time-series data of the rotation signal A, the detection target for the peak value PV can be limited, and the peak value PV can be acquired more accurately. By accurately acquiring the peak value PV, the vibration component of the rotating body 21 of the rotating machine 2 can be acquired accurately. Furthermore, according to the above configuration, since the detection target for the peak value PV can be limited, it is possible to detect the peak value PV and acquire the vibration signal C without using equipment with high computing power, which would be required to directly detect the peak value PV from the time-series data of the rotation signal A.

[0033] In the vibration monitoring device 1 according to some embodiments, as shown in FIG. 5 , the first peak value PVA of the plurality of peak values ​​PV (PV1 to PV11) is held in the vibration signal C from the first peak value PVA to the second peak value PVB, which is the peak value next to the first peak value PVA. For example, during the period from when peak value PV1 is acquired to when peak value PV2 is acquired, peak value PV1 becomes the vibration signal C. That is, as shown in FIG. 5 , the signal waveform acquired from the vibration signal C is such that each of the plurality of peak values ​​PV (PV1 to PV11) changes in a step-like manner.

[0034] According to the above configuration, the peak value PV (PVA) is obtained by holding the interval between the plurality of peak values ​​PV (PVA, PVB), which makes it easy to acquire the vibration signal C. Therefore, the vibration signal acquisition unit 5 can acquire the vibration signal C from the plurality of segments S without using a device with high computing power.

[0035] In the vibration monitoring device 1 according to some embodiments, when the above-mentioned threshold value is defined as TL and the above-mentioned design peak value of the impeller portion 25 is defined as SP, the threshold value TL satisfies the condition 40% SP≦TL≦60% SP. The design peak value SP may be set based on steady-state test data, or may be set based on past actual values, experimental values, numerical analysis results, or the like other than steady-state test data.

[0036] According to the above configuration, there is no problem in excluding from the detection target of the peak value PV those whose output is less than half or approximately half (40% SP≦TL≦60%SP) of the design peak value SP of the impeller portion 25. In this case, the detection target of the peak value PV can be effectively limited, and the peak value PV can be obtained with high accuracy.

[0037] 1 , a vibration monitoring device 1 according to some embodiments further includes a filter command value output unit 6 and a band-pass filter 7. The filter command value output unit 6 is electrically connected to the rotation sensor 3 and is capable of acquiring a rotation signal A that is an output value of the rotation sensor 3. The band-pass filter 7 is electrically connected to the vibration signal acquisition unit 5 and the filter command value output unit 6 and is capable of acquiring a vibration signal C that is an output value of the vibration signal acquisition unit 5 and a filter command value B that is an output value of the filter command value output unit 6.

[0038] (Filter Command Value Output Unit) The filter command value output unit 6 outputs a filter command value B corresponding to the rotation speed N of the rotating body 21 calculated from the rotation signal A. The filter command value output unit 6 is a computer such as an electronic control device, and includes a processor such as a CPU or GPU, memories such as ROM and RAM, an I / O interface, etc. (not shown). The filter command value output unit 6 realizes each functional unit included in the filter command value output unit 6 by the processor operating (calculating, etc.) in accordance with instructions of a program loaded into the memory.

[0039] In the illustrated embodiment, the filter command value output unit 6 includes a rectifier 61, a frequency divider 62, a rotation speed calculator 63, and a converter 64, as shown in Fig. 1. Fig. 6 is an explanatory diagram for explaining a pulse signal F and a rotation pulse signal G in one embodiment of the present disclosure. Fig. 6 shows one cycle of a rotation signal A, and the pulse signal F and rotation pulse signal G corresponding to the rotation signal A.

[0040] Rectifier 61 rectifies rotation signal A output by rotation sensor 3 and converts it into a pulse signal F that includes pulses (portions F1 where the waveform displacement changes significantly) equal to the number of blades 27 during one rotation of rotor 21. Frequency divider 62 divides the frequency of pulse signal F converted by rectifier 61 and converts it into a rotation pulse signal G that includes one pulse (portion G1 where the waveform displacement changes significantly) during one rotation of rotor 21.

[0041] The rotation speed calculator 63 calculates the rotation speed N of the rotating body 21 based on the rotation pulse signal G converted by the frequency divider 62. For example, the rotation speed calculator 63 counts the number of pulses included in the rotation pulse signal G per unit time and calculates the rotation speed N of the rotating body 21 based on the number of pulses per unit time. The converter 64 receives the rotation speed N of the rotating body 21 calculated by the rotation speed calculator 63 and outputs a filter command value B corresponding to the rotation speed N. The filter command value B output from the converter 64 may change from moment to moment in response to the rotation signal A and the rotation speed N, which change from moment to moment. In the illustrated embodiment, the filter command value B is a voltage value obtained by converting the rotation speed N of the rotating body 21 using a preset conversion method. Note that in some embodiments, the filter command value B may be a current value obtained by converting the rotation speed N of the rotating body 21 using a preset conversion method.

[0042] (Band-pass Filter) The band-pass filter 7 receives the vibration signal C acquired from the vibration signal acquisition unit 5 and the filter command value B acquired from the filter command value output unit 6 (converter 64), and extracts a signal in a pass band including a center frequency FB set according to the filter command value B from the vibration signal C as a rotation-synchronized vibration signal E, which is a signal related to vibration synchronized with the rotation of the impeller unit 25. The band-pass filter 7 outputs the rotation-synchronized vibration signal E. The rotation-synchronized vibration signal E is a signal from which information about the vibration synchronized with the rotation of the impeller unit 25 described above can be obtained. The information about the vibration synchronized with the rotation is, for example, the frequency, the magnitude of the vibration, or the speed of the vibration. The rotation-synchronized vibration signal E includes information about the amplitude and phase angle of the rotation-synchronized vibration signal E. As shown in FIG. 5 , the phase angle of the rotation-synchronized vibration signal E corresponds to the phase angle of the rotation signal A and the phase angle of the vibration signal C.

[0043] 7 is a diagram showing the amplitude-frequency characteristics of the band-pass filter 7. In FIG. 7, the horizontal axis represents frequency shown on a logarithmic scale, and the vertical axis represents decibel values. In FIG. 7, V1 represents the characteristics of the band-pass filter 7 when the voltage value (filter command value B) is 0.1 V, V2 represents the characteristics of the band-pass filter 7 when the voltage value is 1 V, and V3 represents the characteristics of the band-pass filter 7 when the voltage value is 10 V.

[0044] In FIG. 7 , the decibel value corresponds to signal strength, and when the decibel value is less than 0, the rotation-synchronized vibration signal E extracted by the band-pass filter 7 is attenuated. As shown in FIG. 7 , for each voltage value (V1 to V3), the decibel value decreases as the frequency moves away from the center frequency FB of the pass band of the band-pass filter 7, and the attenuation rate of the rotation-synchronized vibration signal E increases. This center frequency FB is set in accordance with the filter command value B (a value corresponding to the rotation speed N) obtained from the converter 64 of the filter command value output unit 6. Specifically, this center frequency FB is set to match or approximately match the rotation speed N calculated by the rotation speed calculator 63 of the filter command value output unit 6. For example, the band-pass filter 7 may attenuate the rotation-synchronized vibration signal E in accordance with the filter command value B so as to satisfy 0.8N≦FB≦1.2N. Furthermore, if the rotation speed N is proportional to the filter command value B, the center frequency FB may be set so that the filter command value B is proportional to the center frequency FB. The upper and lower limits of the pass band of the band pass filter 7 are set on both sides of the center frequency FB in accordance with the filter command value B.

[0045] According to the above configuration, by setting the center frequency FB of the passband of the bandpass filter 7 to be the same or approximately the same as the rotation speed N of the impeller section 25 (rotating body 21), the bandpass filter 7 can accurately extract the rotation-synchronized vibration signal E from the vibration signal C. Vibrations synchronized with the rotation of the impeller section 25 (rotating body 21) (vibrations having a frequency equal to or approximately equal to the rotation speed) can be evaluated with high accuracy based on the rotation-synchronized vibration signal E. This makes it possible to evaluate and determine imbalance of the rotating body 21 of the rotating machine 2 (for example, imbalance due to scale adhesion), bending of the rotating shaft 24 which is the rotation axis of the rotating body 21, contact between the rotating body 21 and a stationary body (casing 23), etc., and makes it possible to propose optimal maintenance for the rotating machine 2 and prevent failures of the rotating machine before they occur.

[0046] In the vibration monitoring device 1 according to some embodiments, the relationship 0.8N≦FB≦1.2N is satisfied, where FB is the center frequency of the bandpass filter 7 described above, and N is the rotation speed of the rotor 21 described above. In this case, the center frequency FB of the pass band of the bandpass filter 7 is set to be the same or substantially the same (0.8N≦FB≦1.2N) as the rotation speed N of the impeller portion 25 (rotor 21), so that the bandpass filter 7 can accurately extract the rotation-synchronized vibration signal E from the vibration signal C.

[0047] In the vibration monitoring device 1 according to some embodiments, the above-mentioned filter command value B is a voltage value or current value obtained by converting the rotation speed N of the rotating body 21 calculated from the rotation signal A. The filter (band-pass filter 7) often has a cutoff frequency that can be set according to the voltage value or current value. With the above configuration, the pass band of the band-pass filter 7 can be set arbitrarily according to the rotation speed N. Furthermore, since filters (band-pass filters 7) are generally commercially available at low cost, an increase in the cost of the vibration monitoring device 1 can be suppressed.

[0048] (Display of Vibration Signal) As shown in FIG. 1 , the vibration monitoring device 1 according to some embodiments further includes a display unit 11. The display unit 11 is electrically connected to the vibration signal acquisition unit 5 and is capable of acquiring the vibration signal C, which is an output value of the vibration signal acquisition unit 5. The display unit 11 is configured to display the amplitude of the vibration signal C, i.e., the vibration waveform of the vibration signal C, based on the vibration signal C acquired from the vibration signal acquisition unit 5. In the embodiment shown in FIG. 1 , the display unit 11 displays the amplitude of the vibration signal C on a display device (display) 111, but the amplitude of the vibration signal C may be displayed on a device other than the display device 111. The display unit 11 may also be configured to change the amplitude of the vibration signal C displayed on the display device 111 from time to time in accordance with the output value of the vibration signal acquisition unit 5, which changes from time to time.

[0049] According to the above configuration, the amplitude of the total vibration of the impeller portion 25 (rotor 21) can be detected and displayed on the display unit 11. A viewer viewing the display displayed by the display unit 11 can evaluate the vibration of the impeller portion 25 (rotor 21) with high accuracy based on the amplitude of the total vibration of the impeller portion 25 (rotor 21) displayed by the display unit 11.

[0050] (Display of Rotation-Synchronized Vibration Signal) As shown in FIG. 1 , the vibration monitoring device 1 according to some embodiments further includes a display unit 12. The display unit 12 is electrically connected to the band-pass filter 7 and is capable of acquiring the rotation-synchronized vibration signal E, which is the output value of the band-pass filter 7. The display unit 12 displays the amplitude and phase angle of the rotation-synchronized vibration signal E, i.e., the vibration waveform of the rotation-synchronized vibration signal E, based on the rotation-synchronized vibration signal E acquired from the band-pass filter 7. In the embodiment shown in FIG. 1 , the display unit 12 displays the amplitude and phase angle of the rotation-synchronized vibration signal E on a display device (display) 121. However, the amplitude and phase angle of the rotation-synchronized vibration signal E may also be displayed on a device other than the display device 121 (e.g., the display device 111). The display unit 12 may also change the amplitude and phase angle of the rotation-synchronized vibration signal E displayed on the displays 111 and 121 from time to time in accordance with the output value of the band-pass filter 7, which changes from time to time.

[0051] According to the above configuration, the amplitude and phase of rotation-synchronous vibration (vibration having a frequency that is one times the rotation frequency), which is vibration synchronized with the rotation of the impeller portion 25 (rotor 21), can be detected and displayed on the display unit 12. A viewer viewing the display displayed by the display unit 12 can evaluate the vibration synchronized with the rotation of the impeller portion 25 (rotor 21) with high accuracy based on the amplitude and phase of the rotation-synchronous vibration displayed by the display unit 12, and can therefore accurately determine, for example, the critical speed of the shaft system of the rotating machine 2, a contact event, the above-mentioned unbalance, and the like.

[0052] (Vibration Monitoring Method) Figure 8 is a flow diagram showing an example of a vibration monitoring method according to an embodiment of the present disclosure. As shown in Figure 8, a vibration monitoring method according to some embodiments includes a rotation signal output step S100, a segment acquisition step S200, and a vibration signal acquisition step S300. In the rotation signal output step S100, the rotation sensor 3 is caused to output a rotation signal A whose output changes depending on the distance D from the impeller portion 25.

[0053] In the segment acquisition step S200, the above-mentioned multiple segments S in which the output of the rotation signal A exceeds a predetermined threshold (trigger level) TL are acquired from the rotation signal A output from the rotation sensor 3 in the rotation signal output step S100. Specifically, if the output of the rotation signal A exceeds the predetermined threshold TL ("Yes" in S201), the rotation signal A is acquired (S202). This acquisition of the rotation signal A is continued while the state in which the output of the rotation signal A exceeds the predetermined threshold TL continues. If the output of the rotation signal A does not satisfy the predetermined threshold TL ("No" in S201), the rotation signal A is not acquired. The segment acquisition step S200 may be performed by the segment acquisition unit 4 described above, or may be performed by a computer other than the segment acquisition unit 4, such as an electronic control device.

[0054] In the vibration signal acquisition step S300, a peak value PV is detected from each of the multiple segments S acquired in the segment acquisition step S200 (S301), and a vibration signal C, which is a signal related to the vibration of the impeller section 25, is acquired based on changes in the detected peak values ​​PV (S302). In the vibration signal acquisition step S300, each time a new segment S is acquired in the segment acquisition step S200, the peak value PV corresponding to the new segment S may be detected and the vibration signal C may be acquired. The vibration signal acquisition step S300 may be performed by the vibration signal acquisition unit 5 described above, or may be performed by a computer other than the vibration signal acquisition unit 5, such as an electronic control device.

[0055] According to the above method, peak values ​​PV (PV1 to PV11) can be detected from each of the multiple segments S (S1 to S11), and a vibration signal C corresponding to changes in the peak values ​​PV can be obtained. That is, among the time-series data of the rotation signal A, segments whose output does not satisfy the predetermined threshold value TL can be excluded from the detection target for the peak value PV, and each of the multiple segments S can be used as the detection target for the peak value PV. In this case, compared to directly detecting the peak value PV from the time-series data of the rotation signal A, the detection target for the peak value PV can be limited, and the peak value PV can be obtained more accurately. By accurately obtaining the peak value PV, the vibration component of the rotating body 21 of the rotating machine 2 can be obtained accurately. Furthermore, according to the above configuration, since the detection target for the peak value PV can be limited, it is possible to detect the peak value PV and obtain the vibration signal C without using equipment with high computing power, which would be required to directly detect the peak value PV from the time-series data of the rotation signal A.

[0056] 1, a turbocharger 2A according to some embodiments includes the vibration monitoring device 1 described above, a compressor 25A including an impeller unit 25 provided at one end of the rotor 21 described above, and a turbine 25B provided at the other end of the rotor 21 described above. In this case, it is possible to acquire a vibration signal C of the rotor 21 of the turbocharger 2A from a rotation signal A of the impeller unit 25 of the turbocharger 2A without using equipment with high computing power.

[0057] In this specification, expressions expressing relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such arrangements, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions expressing that things are in an equal state, such as "identical," "equal," and "homogeneous," not only express a state in which there is a strict equivalence, but also express a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions expressing shapes such as a rectangular shape or a cylindrical shape not only express shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also express shapes including concave and convex portions, chamfered portions, etc., to the extent that the same effect is obtained. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components.

[0058] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0059] The contents of the above-described embodiments can be understood, for example, as follows.

[0060] 1) A vibration monitoring device (1) according to at least one embodiment of the present disclosure is a vibration monitoring device (1) for monitoring vibrations of a rotating body (21) including an impeller section (25) of a rotating machine (2), comprising: a rotation sensor (3) arranged at a radial distance from the impeller section (25), the rotation sensor (3) outputting a rotation signal (A) synchronized with the rotation of the rotating body (21), and configured such that the output of the rotation signal (A) changes depending on the distance (D) between the impeller section (25) and the rotation sensor (3); a segment acquisition unit (4) acquiring a plurality of segments (S) of the rotation signal (A) whose output exceeds a predetermined threshold (TL); and a vibration signal acquisition unit (5) detecting a peak value (PV) from each of the plurality of segments (S) and acquiring a vibration signal (C) which is a signal related to the vibration of the impeller section (25) based on changes in the peak value (PV).

[0061] According to the configuration 1), a peak value (PV) can be detected from each of the multiple segments (S), and a vibration signal (C) corresponding to changes in the peak value (PV) can be acquired. That is, among the time-series data of the rotation signal (A), segments whose output does not satisfy the predetermined threshold (TL) can be excluded from the peak value (PV) detection targets, and each of the multiple segments (S) can be used as the peak value (PV) detection target. In this case, compared to when the peak value (PV) is directly detected from the time-series data of the rotation signal (A), the peak value (PV) can be more accurately acquired because the peak value (PV) detection target can be limited. By accurately acquiring the peak value (PV), the vibration component of the rotating body (21) of the rotating machine (2) can be accurately acquired. Furthermore, according to the configuration 1), the peak value (PV) detection target can be limited, making it possible to detect the peak value (PV) and acquire the vibration signal (C) without using equipment with high computing power, which would be required when directly detecting the peak value (PV) from the time-series data of the rotation signal (A).

[0062] 2) In some embodiments, the vibration monitoring device (1) described in 1) above further includes: a filter command value output unit (6) that outputs a filter command value (B) corresponding to the rotation speed of the rotating body (21) calculated from the rotation signal (A); and a band-pass filter (7) that receives the vibration signal (C) and the filter command value (B) and extracts, from the vibration signal (C), a signal in a pass band including a center frequency (FB) set according to the filter command value (B), as a rotation-synchronous vibration signal (E), which is a signal related to vibration synchronized with the rotation of the impeller unit (25).

[0063] According to the configuration 2) above, by setting the center frequency (FB) of the pass band of the band pass filter (7) to be the same as or approximately the same as the rotation speed (N) of the impeller section (25, rotor 21), the band pass filter (7) can accurately extract the rotation-synchronized vibration signal (E) from the vibration signal (C). Based on the rotation-synchronized vibration signal (E), vibrations synchronized with the rotation of the impeller section (25, rotor 21) (vibrations having a frequency equal to or approximately equal to the rotation speed) can be evaluated with high accuracy.

[0064] 3) In some embodiments, in the vibration monitoring device (1) described in 1) or 2) above, the first peak value (PVA) of the vibration signal (C) is held from a first peak value (PVA) among the plurality of peak values ​​(PV) to a second peak value (PVB) that is next to the first peak value (PVA).

[0065] According to the configuration 3), the peak value (PVA) is held between the plurality of peak values ​​(PVA, PVB), which makes it easy to acquire the vibration signal (C). Therefore, the vibration signal acquisition unit (5) can acquire the vibration signal (C) from the plurality of segments (S) without using a device with high computing power.

[0066] 4) In some embodiments, in the vibration monitoring device (1) described in 2) above, when the center frequency is FB and the rotation speed of the rotating body (21) is N, the relationship 0.8N≦FB≦1.2N is satisfied.

[0067] According to the configuration of 4) above, the center frequency (FB) of the pass band of the band pass filter (7) is set to be the same as or approximately the same as (0.8N≦FB≦1.2N) the rotation speed (N) of the impeller portion (25, rotor 21), so that the rotation-synchronous vibration signal (E) can be extracted with high precision from the vibration signal (C) by the band pass filter (7).

[0068] 5) In some embodiments, the vibration monitoring device (1) described in 2) or 4) above further comprises a display unit (12) that displays the amplitude and phase angle of the rotation-synchronous vibration signal (E) based on the rotation-synchronous vibration signal (E).

[0069] According to the configuration of 5) above, the amplitude and phase of rotation-synchronous vibration (vibration having a frequency that is one time the rotation frequency), which is vibration synchronized with the rotation of the impeller portion (25, rotor 21), can be detected and displayed on the display portion (12). A viewer viewing the display displayed by the display portion (12) can evaluate the vibration synchronized with the rotation of the impeller portion (25, rotor 21) with high accuracy based on the amplitude and phase of the rotation-synchronous vibration displayed by the display portion (12), and can perform highly accurate determinations of, for example, the critical speed of the shaft system of the rotating machine (2), contact events, the above-mentioned unbalance, and the like.

[0070] 6) In some embodiments, the vibration monitoring device (1) described in any one of 1) to 5) above further comprises a display unit (11) that displays the amplitude of the vibration signal (C) based on the vibration signal (C).

[0071] According to the configuration 6) above, the amplitude of the total vibration of the impeller portion (25, rotor 21) can be detected and displayed on the display portion (11). A viewer viewing the display displayed on the display portion (11) can evaluate the vibration of the impeller portion (25, rotor 21) with high accuracy based on the amplitude of the total vibration of the impeller portion (25, rotor 21) displayed on the display portion (11).

[0072] 7) In some embodiments, in the vibration monitoring device (1) described in any one of 1) to 6) above, when the threshold value is defined as TL and the design peak value of the impeller portion (25) is defined as SP, the threshold value TL satisfies the condition 40%SP≦TL≦60%SP.

[0073] According to the configuration of 7) above, outputs less than half or approximately half (40% SP≦TL≦60% SP) of the design peak value (SP) of the impeller section (25) can be excluded from the detection of the peak value (PV). In this case, the detection targets of the peak value (PV) can be effectively limited, and the peak value (PV) can be obtained with high accuracy.

[0074] 8) In some embodiments, in the vibration monitoring device (1) described in any one of 2), 4) and 5) above, the filter command value (B) is a voltage value or a current value obtained by converting the rotation speed (N) of the rotating body (21) calculated from the rotation signal (A).

[0075] The cutoff frequency of the filter (band-pass filter 7) can often be set according to the voltage value or current value. According to the configuration of 8) above, the pass band of the band-pass filter (7) can be set arbitrarily according to the rotation speed (N). Furthermore, since the filter (band-pass filter 7) is generally commercially available at low cost, it is possible to suppress an increase in the cost of the vibration monitoring device (1).

[0076] 9) A turbocharger (2A) according to at least one embodiment of the present disclosure includes: the vibration monitoring device (1) described in any one of 1) to 8) above; a compressor (25A) including the impeller portion (25) provided at one end of the rotating body (21); and a turbine (25B) provided at the other end of the rotating body (21).

[0077] According to the configuration 9), it is possible to acquire the vibration signal (C) of the rotor (21) of the turbocharger (2A) from the rotation signal (A) of the impeller part (25) of the turbocharger (2A) without using a device with high computing power.

[0078] 10) A vibration monitoring method according to at least one embodiment of the present disclosure is a vibration monitoring method for monitoring vibrations of a rotating body (21) including an impeller section (25) of a rotating machine (2), comprising: a rotation signal output step (S100) of outputting, to a rotation sensor (3) arranged radially spaced apart from the impeller section (25), a rotation signal (A) synchronized with the rotation of the rotating body (21), the rotation signal (A) having an output that changes according to a distance (D) between the impeller section (25) and the rotation sensor (3); a segment acquisition step (S200) of acquiring, from the rotation signal (A), a plurality of segments (S) whose output exceeds a predetermined threshold (TL); and a vibration signal acquisition step (S300) of detecting a peak value (PV) from each of the plurality of segments (S) and acquiring a vibration signal (C), which is a signal related to the vibration of the impeller section (25) based on a change in the peak value (PV).

[0079] According to the method of 10), a peak value (PV) can be detected from each of the plurality of segments (S), and a vibration signal (C) corresponding to changes in the peak value (PV) can be acquired. That is, among the time-series data of the rotation signal (A), those whose output does not meet the predetermined threshold (TL) can be excluded from the peak value (PV) detection target, and each of the plurality of segments (S) can be used as the peak value (PV) detection target. In this case, compared to when the peak value (PV) is directly detected from the time-series data of the rotation signal (A), the peak value (PV) can be more accurately acquired because the peak value (PV) can be limited. By accurately acquiring the peak value (PV), the vibration component of the rotating body (21) of the rotating machine (2) can be accurately acquired. Furthermore, according to the method 10) above, since the object of peak value (PV) detection can be limited, it is possible to detect peak values ​​(PV) and obtain vibration signals (C) without using equipment with high computing power, which is required when detecting peak values ​​(PV) directly from the time series data of the rotation signal (A).

[0080] REFERENCE SIGNS LIST 1 vibration monitoring device 2 rotating machine 2A turbocharger 3 rotation sensor 4 segment acquisition unit 5 vibration signal acquisition unit 6 filter command value output unit 7 band pass filter 11, 12 display unit 21 rotating body 22 bearing 23 casing 24 rotating shaft 25 impeller unit 25A compressor 25B turbine 26 hub 27 blade 61 rectifier 62 frequency divider 63 rotation speed calculator 64 converter 111, 121 display device A rotation signal AP amplitude B filter command value C vibration signal CA central axis D distance D1, D2 radial distance E rotation synchronous vibration signal F pulse signal FB central frequency G rotation pulse signal N rotation speed N1 to N11 position PV, PV1 to PV11 peak value PVA: First peak value PVB: Second peak value S: Segment S100: Rotation signal output step S200: Segment acquisition step S300: Vibration signal acquisition step SP: Design peak value TL: Threshold value

Claims

1. A vibration monitoring device for monitoring vibrations of a rotating body including an impeller section of a rotating machine, comprising: a rotation sensor arranged at a radial distance from the impeller section, the rotation sensor outputting a rotation signal synchronized with the rotation of the rotating body, and configured such that the output of the rotation signal changes depending on the distance between the impeller section and the rotation sensor; a segment acquisition unit acquiring multiple segments of the rotation signal whose output exceeds a predetermined threshold; and a vibration signal acquisition unit detecting peak values ​​from each of the multiple segments, and acquiring a vibration signal which is a signal related to the vibration of the impeller section based on the change in the peak value.

2. The vibration monitoring device of claim 1, further comprising: a filter command value output unit that outputs a filter command value corresponding to the rotation speed of the rotating body calculated from the rotation signal; and a band pass filter that receives the vibration signal and the filter command value and extracts from the vibration signal a signal of a pass band including a center frequency set according to the filter command value as a rotation synchronous vibration signal, which is a signal related to vibration synchronized with the rotation of the impeller section.

3. A vibration monitoring device as described in claim 1 or 2, wherein the first peak value of the vibration signal is held from a first peak value of the plurality of peak values ​​to a second peak value that is next to the first peak value.

4. The vibration monitoring device according to claim 2, wherein, assuming that the center frequency is FB and the number of rotations of the rotor is N, 0.8N≦FB≦1.2N is satisfied.

5. The vibration monitoring device according to claim 2 or 4, further comprising a display unit that displays the amplitude and phase angle of the rotation-synchronized vibration signal based on the rotation-synchronized vibration signal.

6. The vibration monitoring device according to claim 1, further comprising a display unit that displays an amplitude of the vibration signal based on the vibration signal.

7. A vibration monitoring device as claimed in any one of claims 1, 2 or 4, wherein, when the threshold value is defined as TL and the design peak value of the impeller portion is defined as SP, the threshold value TL satisfies the condition 40%SP≦TL≦60%SP.

8. A vibration monitoring device according to claim 2 or 4, wherein the filter command value is a voltage value or a current value obtained by converting the rotation speed of the rotating body calculated from the rotation signal.

9. A turbocharger comprising: a vibration monitoring device according to any one of claims 1, 2 or 4; a compressor including the impeller portion provided at one end of the rotor; and a turbine provided at the other end of the rotor.

10. A vibration monitoring method for monitoring vibrations of a rotating body including an impeller section of a rotating machine, comprising: a rotation signal output step of causing a rotation sensor arranged at a radial distance from the impeller section to output a rotation signal synchronized with the rotation of the rotating body, the rotation signal having an output that changes according to the distance between the impeller section and the rotation sensor; a segment acquisition step of acquiring multiple segments of the rotation signal whose output exceeds a predetermined threshold value; and a vibration signal acquisition step of detecting peak values ​​from each of the multiple segments and acquiring a vibration signal that is a signal related to the vibration of the impeller section based on the change in the peak value.

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