Vibration detection device, abnormality detection assistance system, and vibration detection method
By lowering the sampling frequency in the rolling bearing twice the first frequency, the cost of the vibration detection device is reduced, and the problem of high sampling frequency in the prior art is solved, and the equipment cost is high is achieved, and an effective rolling bearing abnormality detection is achieved.
Patent Information
- Application Number
- CN202280097329.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-09-12
- Publication Date
- 2025-02-07
AI Technical Summary
When the sampling frequency reaches more than twice the highest frequency of the vibration signal, the vibration detection device is costly and the equipment is expensive.
By sampling frequency in the rolling bearing twice the first frequency, the sampling unit samples the analog signal at a sampling frequency lower than the first frequency, reducing the cost of the sampling device.
The cost of a vibration detection device for detecting abnormalities of rolling bearings is achieved, while still being able to effectively detect abnormalities of rolling bearings.
Smart Images
Figure CN119404016A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a vibration detection device, an abnormality detection auxiliary system and a vibration detection method for detecting abnormality of a rolling bearing. Background Art
[0002] In the prior art, there is known an abnormality diagnosis device that installs a vibration detection element on a bearing device of a railway vehicle, samples the detected vibration signal, obtains an envelope (envelope curve), and performs FFT-based frequency analysis on the envelope to diagnose whether the bearing is abnormal (for example, refer to Patent Document 1, paragraphs 0025 and 0026).
[0003] Paragraph 0026 of Japanese Patent Document 1 states that the maximum frequency (Nyquist frequency) that can be Fourier transformed is determined according to the sampling time, so it is preferable that the vibration signal does not contain frequencies above the Nyquist frequency. The Nyquist frequency is a frequency that is 1 / 2 of the sampling frequency, so not containing frequencies above the Nyquist frequency in the vibration signal means that the sampling frequency needs to be at least twice the highest frequency contained in the vibration signal.
[0004] Prior art literature
[0005] Patent Literature
[0006] Patent Document 1: Japanese Patent Application Publication No. 2004-212225 Summary of the invention
[0007] However, when sampling is performed at a sampling frequency that is twice or more of the highest frequency included in the vibration signal, the price of components such as an analog-to-digital converter and a sensor for sampling is high, and the vibration detection device for detecting vibration is expensive.
[0008] An object of the present invention is to provide a vibration detection device, an abnormality detection support system, and a vibration detection method that can easily reduce the cost of a vibration detection device for detecting an abnormality of a rolling bearing.
[0009] According to one embodiment of the present invention, a vibration detection device includes: a vibration detection unit, which detects the vibration generated in a rolling bearing and converts it into an analog signal; and a sampling unit, which samples the analog signal and converts it into a digital signal, wherein the vibration is a vibration whose repetitive unit repeats at a prescribed repetitive period when the rolling bearing is damaged, wherein the repetitive unit includes a first vibration interval vibrating at a prescribed first frequency and a second interval following the first vibration interval, and the sampling unit samples the analog signal at a sampling frequency lower than twice the first frequency.
[0010] In addition, according to one scheme of the present invention, an abnormality detection auxiliary system includes: a digital signal acquisition unit, which acquires the digital signal from the above-mentioned vibration detection device; an envelope detection unit, which detects the envelope of the vibration waveform based on the digital signal; and a frequency analysis unit, which performs frequency analysis on the envelope and calculates the analysis value of each frequency component.
[0011] In addition, a vibration detection method according to one embodiment of the present invention includes: a vibration detection step, detecting the vibration generated in the rolling bearing and converting it into an analog signal; and a sampling step, sampling the analog signal and converting it into a digital signal, wherein the vibration is a vibration whose repetitive unit repeats at a prescribed repetitive period when the rolling bearing is damaged, wherein the repetitive unit includes a first vibration interval vibrating at a prescribed first frequency and a second interval following the first vibration interval, and in the sampling step, the analog signal is sampled at a sampling frequency lower than twice the first frequency. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a block diagram showing an example of an abnormality detection support system including a vibration detection device according to an embodiment of the present invention.
[0013] Figure 2 Yes means Figure 1 A block diagram of an example of the electrical configuration of the abnormality detection support system shown.
[0014] Figure 3 It is an explanatory diagram showing an example of the process flow of the abnormality detection support system.
[0015] Figure 4 This is a waveform diagram showing a typical example of a simulation signal indicating vibration when damage occurs in a rolling bearing.
[0016] Figure 5 yes Figure 4 Magnified view of the repeating unit shown.
[0017] Figure 6 This is an explanatory diagram for explaining the structure of a rolling bearing.
[0018] Figure 7 This is an explanatory diagram for explaining sampling by the sampling unit.
[0019] Figure 8 This is an explanatory diagram for explaining folding based on sampling.
[0020] Fig. 9 This is a waveform diagram showing an example of an envelope waveform.
[0021] Fig.10 This is an explanatory diagram that graphically represents the analysis value for each frequency component. DETAILED DESCRIPTION
[0022] Hereinafter, embodiments of the present invention will be described based on the drawings. In addition, in each figure, the same structure as the same reference numerals indicates the same structure, and the description thereof will be omitted. Figure 1 This is a block diagram showing an example of an abnormality detection support system including a vibration detection device according to an embodiment of the present invention.
[0023] Figure 1 The abnormality detection auxiliary system 1 shown includes a vibration detection device 2 and an abnormality detection auxiliary device 3. The vibration detection device 2 is installed, for example, on the housing of a motor M including a rolling bearing B as an abnormality detection object. Alternatively, the vibration detection device 2 may be installed on the housing of a mechanical device including the motor M. The vibration detection device 2 can detect vibration generated in the rolling bearing B by being installed on the motor M including the rolling bearing B.
[0024] The rolling bearing B includes an outer ring B1, an inner ring B2 and a rotating body B3. The rolling bearing B is not limited to the motor M, but can be used for various purposes. The vibration detection device 2 can be installed at a location where the vibration generated by the rolling bearing B can be transmitted.
[0025] Figure 2 Yes means Figure 1 FIG. 2 is a block diagram showing an example of an electrical configuration of the abnormality detection support system 1 shown in FIG. Figure 2 The abnormality detection assisting system 1 shown includes a vibration detection device 2 and an abnormality detection assisting device 3 .
[0026] The vibration detection device 2 includes a vibration detection unit 21, a sampling unit 22, and a communication unit 23. The vibration detection unit 21 and the sampling unit 22 may be integrally configured as, for example, the acceleration sensor 20 or the like.
[0027] The vibration detection unit 21 detects vibration and converts it into an analog signal A, and outputs it to the sampling unit 22. The vibration detection unit 21 can detect vibration as acceleration, can detect single-axis vibration, or can detect vibration in mutually orthogonal X-axis, Y-axis and Z-axis directions, and outputs analog signals Ax, Ay, Az representing the vibration in the X-axis, Y-axis and Z-axis directions as the analog signal A to the sampling unit 22.
[0028] Acceleration is an example of information indicating vibration. The vibration detection unit 21 only needs to be able to detect vibration, and is not limited to detecting vibration by acceleration. The vibration detection unit 21 may detect vibration by velocity, or may detect vibration by displacement, for example.
[0029] The sampling unit 22 samples the analog signal A, converts it into a digital signal D, and outputs it to the communication unit 23. The sampling unit 22 is configured as an analog-to-digital converter, for example. The sampling unit 22 samples the analog signal A at a sampling frequency Fs.
[0030] The communication unit 23 is a communication interface circuit capable of wirelessly communicating with the abnormality detection support device 3. The communication unit 23 transmits the digital signal D to the abnormality detection support device 3 by wireless communication.
[0031] The abnormality detection support device 3 is configured using, for example, a personal computer and includes, for example, a computing unit 31 , a communication unit 32 (digital signal acquisition unit), a display 33 , a keyboard 34 , and a mouse 35 .
[0032] The communication unit 32 is a communication interface circuit capable of wireless communication with the communication unit 23 of the vibration detection device 2. The communication unit 32 obtains the digital signal D sent from the vibration detection device 2 and sends it to the calculation unit 31. The communication method of the communication units 23 and 32 can use various wireless communication methods such as WiFi (registered trademark) and Bluetooth (registered trademark).
[0033] In addition, the communication units 23 and 32 are not limited to the example of wireless communication, and wired communication may be performed. Alternatively, the digital signal D output from the sampling unit 22 may be stored in a storage medium such as a memory card, and the abnormality detection auxiliary device 3 may read the storage medium so that the abnormality detection auxiliary device 3 acquires the digital signal D. In this case, the reading device that reads the storage medium is equivalent to an example of a digital signal acquisition unit.
[0034] In addition, the vibration detection device 2 and the abnormality detection auxiliary device 3 may be configured as an integrated device. In this case, the communication units 23 and 32 may not be required, and the digital signal D output from the sampling unit 22 may be directly or indirectly input to the calculation unit 31. In this case, the calculation unit 31 is equivalent to an example of a digital signal acquisition unit.
[0035] The computing unit 31 is configured using, for example, a microcomputer. The computing unit 31 is configured using, for example, a CPU (Central Processing Unit) that performs predetermined computing processing, a RAM (Random Access Memory) that temporarily stores data, a non-volatile storage device such as an HDD (Hard Disk Drive), or an SSD (Solid State Drive), and their peripheral circuits.
[0036] Furthermore, the calculation unit 31 functions as an envelope detection unit 311 , a frequency analysis unit 312 , and an abnormality determination unit 313 , for example, by executing an abnormality detection support program pre-stored in the storage device.
[0037] The envelope detection unit 311 detects the envelope of the vibration waveform based on the digital signal D.
[0038] The frequency analysis unit 312 performs frequency analysis on the envelope detected by the envelope detection unit 311 , and calculates an analysis value for each frequency component.
[0039] The abnormality determination unit 313 determines that an abnormality exists when the magnitude of the analysis value of each frequency component calculated by the frequency analysis unit 312 exceeds a reference value preset within a reference frequency range including a repetition frequency Fr which is the inverse of a repetition period Tr described later.
[0040] Next, Figure 1 The operation of the abnormality detection support system 1 shown will be described. Figure 3 1 is an explanatory diagram showing an example of the process flow of the abnormality detection support system 1. Figure 3 In the figure, the transmission and reception of the digital signal D performed by the communication units 23 and 32 are omitted.
[0041] First, the vibration detection unit 21 detects the vibration generated in the rolling bearing B, converts it into an analog signal A, and outputs it to the sampling unit 22 .
[0042] Figure 4 FIG. 1 is a waveform diagram showing a typical example of a simulation signal A showing vibration when a rolling bearing B is damaged. It is known that when a rolling bearing B is damaged, Figure 4 As shown, the repetition unit A1 becomes a vibration waveform that is repeated at intervals of the repetition period Tr.
[0043] Figure 5 yes Figure 4 An enlarged view of an example of a repeating unit A1 shown. The repeating unit A1 includes a first interval Z1 vibrating at a first frequency F1 and a second interval Z2 following the first interval Z1. The second interval Z2 is an interval where the vibration of the first interval Z1 converges. The amplitude of the analog signal A in the second interval Z2 is, for example, less than 1 / 10 of the maximum amplitude of the analog signal A in the first interval Z1.
[0044] The frequency of the analog signal A in the first section Z1 is the first frequency F1. When the frequency of the analog signal A in the first section Z1 deviates, the maximum frequency in the fluctuation range may be taken as the first frequency F1.
[0045] It is known that the repetition frequency Fr, which is the inverse of the repetition period Tr, is determined by the structure of the rolling bearing B, the rotation speed, and the position of damage. Figure 6 This is an explanatory diagram for explaining the structure of the rolling bearing B. When the rotation frequency of the rolling bearing B is set to Fb, the pitch circle diameter of the rolling bearing B is set to Da, the diameter of the rotating body B3 is set to Db, the contact angle of the rotating body B3 is set to R, and the number of rotating bodies is set to N, the repetition frequency Fr when damage occurs in the outer ring B1 and the inner ring B2 is respectively expressed as the following formula (1) and formula (2).
[0046] The repetition frequency when damage occurs in the outer ring B1 is Fr = (N / 2) × Fb × {1-(Db / Da)cosR}…(1)
[0047] The repetition frequency when damage occurs in the inner ring B2 is Fr = (N / 2) × Fb × {1 + (Db / Da) cosR} ... (2)
[0048] Reference Figure 3 Next, the sampling unit 22 samples the analog signal A at the sampling frequency Fs and converts it into a digital signal D. Figure 7 2 is an explanatory diagram for explaining sampling performed by the sampling unit 22. Figure 7 In FIG. 1 , the waveform of the analog signal A is indicated by a dotted line, and the waveform represented by the digital signal D is indicated by a solid line. In addition, the sampling point is indicated by a mark x.
[0049] The sampling frequency Fs is lower than twice the first frequency F1, which is the frequency of the analog signal A in the first section Z1. Therefore, the analog signal A in the first section Z1 is undersampled.
[0050] In addition, the sampling period Ts, which is the reciprocal of the sampling frequency Fs, is shorter than 1 / 2 of the repetition period Tr. Therefore, the sampling frequency Fs becomes a frequency higher than twice the repetition frequency Fr. In addition, it is desirable that the sampling frequency Fs is a frequency as high as possible within a range lower than twice the first frequency F1. For example, it is more preferable to set the sampling period Ts to be shorter than 1 / 4 of the repetition period Tr and to set the sampling frequency Fs to be a frequency higher than four times the repetition frequency Fr.
[0051] Figure 8 1 is an explanatory diagram for explaining the folding caused by sampling the analog signal A at a sampling frequency Fs lower than twice the first frequency F1. Figure 8 In FIG. 1 , the analog signal A is represented by a spectrum with the horizontal axis being the frequency and the vertical axis being the signal strength. 0.5Fs is the Nyquist frequency.
[0052] like Figure 8As shown in FIG. 1 , the frequency portion of the analog signal A representing vibration that is higher than the Nyquist frequency (0.5Fs) is folded into a frequency portion lower than the Nyquist frequency (0.5Fs) and sampled. As a result, as shown in the folding diagram E, signals of different frequencies overlap, and the sum of the intensities of these signals becomes the waveform shown in the sampled digital signal D.
[0053] When signals of different frequencies are folded and overlapped like this, the frequency and waveform of the vibration signal cannot be correctly grasped. This is called "foldback noise" in the past, and measures to prevent such folding are required. However, what is detected by the abnormality detection auxiliary system 1 is the envelope, that is, the overall intensity change, so there is no problem even if the sum of the intensities of the original multiple frequency signals is captured as the intensity of the signal of one frequency.
[0054] Next, the envelope detection unit 311 performs an offset removal process to remove the DC component outside the analysis object from the digital signal D generated by the sampling unit 22, and generates a sampling waveform D1 (step S1). When the signal waveform represented by the digital signal D has an offset, the shape of the envelope changes. Therefore, the target waveform cannot be obtained. As a result, the detection sensitivity of abnormality detection decreases. Therefore, it is preferred that the envelope detection unit 311 performs an offset removal process (step S1).
[0055] Next, the envelope detection unit 311 obtains the envelope of the signal waveform represented by the sampling waveform D1 by performing, for example, Hilbert transform on the sampling waveform D1 (step S2 ), and generates an envelope waveform D2 representing the envelope.
[0056] Fig. 9 : is a waveform diagram showing an example of the envelope waveform D2. Fig. 9 In FIG. 1 , the envelope waveform D2 is indicated by a solid line, and the envelope waveform Dx obtained when sampling is performed assuming that the sampling frequency Fs is set to be twice or more of the first frequency F1 is indicated by a dotted line.
[0057] The sampling frequency Fs of the envelope waveform D2 is less than twice the first frequency F1, and does not satisfy the sampling theorem. As a result, the envelope waveform Dx and the envelope waveform D2 whose sampling frequency Fs satisfies the sampling theorem become different waveforms in the first section Z1. However, although the waveform is different from that of the envelope waveform Dx, the feature that the vibration waveform appears at intervals of the repetition period Tr in the envelope waveform D2 is maintained in the same manner as the envelope waveform Dx.
[0058] That is, even the envelope waveform D2 that does not satisfy the sampling theorem includes a frequency component of the repetition frequency Fr that is the inverse of the repetition period Tr.
[0059] Next, the envelope detection unit 311 performs a process of acquiring the absolute value of a complex number on the envelope waveform D2 to generate an envelope waveform D3 (step S3 ).
[0060] Then, the frequency analysis unit 312 performs an offset removal process to remove the DC component outside the analysis object from the envelope waveform D3 generated by the envelope detection unit 311, and generates the analysis object waveform D4 (step S4). When the envelope waveform D3 has a DC component (offset), a strong peak in the range of 0 to 2 Hz appears when performing the high-speed Fourier transform (FFT) of step S5. Therefore, even if there is a peak below 2 Hz due to damage to the rolling bearing B, it is impossible to distinguish whether it is a peak caused by damage or a peak caused by offset, and there is a concern that the abnormality of the rolling bearing B cannot be determined.
[0061] Therefore, it is preferable that the frequency analysis unit 312 executes the offset removal process of step S4 to execute the offset removal process of removing the DC component from the envelope waveform D3 (step S4 ).
[0062] Next, the frequency analysis unit 312 performs frequency analysis using fast Fourier transform (FFT) based on the analysis target waveform D4 , and calculates an analysis value D5 for each frequency component (step S5 ).
[0063] Fig.10 This is an explanatory diagram showing the analysis value D5 for each frequency component in a graph. Fig.10 As a comparison target, an analysis value Dy based on the envelope waveform Dx obtained by sampling when the sampling frequency Fs is set to be twice or more of the first frequency F1 is shown.
[0064] like Fig.10 As shown, even the undersampled analysis value D5 whose sampling frequency Fs is less than twice the first frequency F1 has a peak at the repetition frequency Fr, similar to the analysis value Dy satisfying the sampling theorem whose sampling frequency Fs is more than twice the first frequency F1.
[0065] The frequency analysis unit 312 may also be as follows, for example Fig.10 As shown, the analysis value D5 for each frequency component is graphed in a two-dimensional plane with frequency on one axis and analysis value on the other axis and displayed on the display 33. The user can detect abnormality of the rolling bearing B by checking the presence or absence of a peak of the repetition frequency Fr by viewing the graphed analysis value D5.
[0066] Next, when the magnitude of the analysis value D5 of each frequency component exceeds a reference value pre-set within the frequency range including the repetition frequency Fr, that is, within the reference frequency range, the abnormality determination unit 313 determines that the rolling bearing B is abnormal. The reference value can be obtained through experiments and appropriately set, for example. The abnormality determination unit 313 can also display the determination result on the display 33.
[0067] The reference frequency range includes an outer ring frequency range set corresponding to the outer ring B1 and an inner ring frequency range set corresponding to the inner ring B2, wherein the outer ring frequency range set corresponding to the outer ring B1 is the outer ring frequency range including the repetition frequency Fr when the outer ring B1 is damaged, and the inner ring frequency range set corresponding to the inner ring B2 is the inner ring frequency range including the repetition frequency Fr when the inner ring B2 is damaged.
[0068] As the outer ring frequency range, for example, a value having a width including the measurement error of the vibration detection device 2, the calculation error of the envelope detection unit 311 and the frequency analysis unit 312, etc. can be used with respect to the repetition frequency Fr when the outer ring B1 is damaged as shown in equation (1). As the inner ring frequency range, for example, a value having a width including the measurement error of the vibration detection device 2, the calculation error of the envelope detection unit 311 and the frequency analysis unit 312 can be used with respect to the repetition frequency Fr when the inner ring B2 is damaged as shown in equation (2).
[0069] The abnormality judgment unit 313 can judge that the outer ring B1 of the rolling bearing B is abnormal when the size of the analysis value D5 of each frequency component exceeds the reference value within the outer ring frequency range, and can judge that the inner ring B2 of the rolling bearing B is abnormal when the size of the analysis value D5 of each frequency component exceeds the reference value within the inner ring frequency range.
[0070] As described above, according to the vibration detection device 2 and the abnormality detection support system 1, it is possible to detect the abnormality of the rolling bearing B while setting the sampling frequency Fs to be under-sampling lower than twice the first frequency F1. As a result, the sampling unit 22 can be configured using an analog-to-digital converter or the like that has a low sampling frequency Fs and is therefore inexpensive. Therefore, it is easy to reduce the cost of the vibration detection device 2 for detecting the abnormality of the rolling bearing B and the abnormality detection support system 1 using the vibration detection device 2.
[0071] In addition, the abnormality detection support system 1 may not include the abnormality determination unit 313. In addition, the envelope detection unit 311 may not perform the offset removal process (step S1) but perform the Hilbert transform (step S2) on the digital signal D. In addition, the envelope detection unit 311 only needs to be able to obtain the envelope, and the method of obtaining the envelope is not limited to the Hilbert transform.
[0072] In addition, the envelope detection unit 311 may not perform the process of obtaining the absolute value of the complex number (step S3), and the frequency analysis unit 312 may perform the offset removal process (step S4) on the envelope waveform D2. In addition, the frequency analysis unit 312 may not perform the offset removal process (step S4), but perform a fast Fourier transform (step S5) on the envelope waveform D2 or the envelope waveform D3.
[0073] That is, a vibration detection device according to one scheme of the present invention includes: a vibration detection unit, which detects the vibration generated in a rolling bearing and converts it into an analog signal; and a sampling unit, which samples the analog signal and converts it into a digital signal, wherein the vibration is a vibration repeated at a specified repetition period in a repetition unit including a first vibration interval vibrating at a specified first frequency and a second interval following the first vibration interval when the rolling bearing is damaged, and the sampling unit samples the analog signal at a sampling frequency lower than twice the first frequency.
[0074] In addition, a vibration detection method according to one embodiment of the present invention includes: a vibration detection step, detecting the vibration generated in the rolling bearing and converting it into an analog signal; and a sampling step, sampling the analog signal and converting it into a digital signal, wherein the vibration is a vibration repeated at a specified repetition period in a repetition unit including a first vibration interval vibrating at a specified first frequency and a second interval following the first vibration interval when the rolling bearing is damaged, and in the sampling step, the analog signal is sampled at a sampling frequency lower than twice the first frequency.
[0075] With these configurations, sampling can be performed at a frequency lower than twice the first frequency, so that inexpensive components can be used as components for sampling. As a result, the cost of the vibration detection device for detecting abnormalities in rolling bearings can be easily reduced.
[0076] Furthermore, it is preferred that the sampling frequency is lower than twice the first frequency.
[0077] Through this structure, it is apparent that sampling can be performed at a low frequency that does not satisfy the sampling theorem relative to the first frequency.
[0078] Furthermore, it is preferred that the sampling period is shorter than 1 / 2 of the repetition period.
[0079] With this configuration, the sampled digital signal includes a frequency component of a repetition frequency that is the inverse of the repetition period.
[0080] In addition, according to one scheme of the present invention, an abnormality detection auxiliary system includes: a digital signal acquisition unit, which acquires the digital signal from the above-mentioned vibration detection device; an envelope detection unit, which detects the envelope of the vibration waveform based on the digital signal; and a frequency analysis unit, which performs frequency analysis on the envelope and calculates the analysis value of each frequency component.
[0081] This structure can obtain an analysis value for each frequency component of the envelope of the digital signal sampled at a frequency twice lower than the first frequency. By obtaining an analysis value for each frequency component, it is easy to detect abnormalities in the rolling bearing based on the analysis value.
[0082] Furthermore, it is preferable to further include an abnormality determination unit that determines that an abnormality occurs when the magnitude of the analysis value of each frequency component exceeds a reference value preset within a frequency range including a repetition frequency that is an inverse of the repetition period, that is, a reference frequency range.
[0083] With this configuration, abnormality of the rolling bearing can be automatically detected.
[0084] Furthermore, preferably, the reference frequency range includes an outer ring frequency range set corresponding to the outer ring of the rolling bearing, and the abnormality determination unit determines that the outer ring is abnormal when the magnitude of the analysis value of each frequency component exceeds the reference value within the outer ring frequency range.
[0085] With this structure, an abnormality in the outer ring of the rolling bearing can be automatically detected.
[0086] In addition, it is preferred that the reference frequency range includes an inner ring frequency range set corresponding to the inner ring of the rolling bearing, and the abnormality judgment unit judges that the inner ring is abnormal when the size of the analysis value of each frequency component exceeds the reference value within the inner ring frequency range.
[0087] With this configuration, an abnormality in the inner ring of the rolling bearing can be automatically detected.
[0088] Furthermore, it is preferred that the vibration detection device is further included.
[0089] According to this configuration, the vibration detection device is included in the abnormality detection support system.
[0090] In addition, the specific embodiments and examples described in the aspects of the mode for carrying out the invention are merely examples for explaining the technical contents of the invention, and the invention should not be limited to such specific examples and should not be narrowly interpreted.
[0091] Explanation of symbols
[0092] 1. Anomaly Detection Assistance System
[0093] 2 Vibration detection device
[0094] 3. Abnormality detection auxiliary device
[0095] 20 Accelerometer
[0096] 21. Vibration detection unit
[0097] 22 Sampling Department
[0098] 23 Ministry of Communications
[0099] 31 Calculation unit (digital signal acquisition unit)
[0100] 32 Communications Department (Digital Signal Acquisition Department)
[0101] 33 Display
[0102] 311 Envelope Detection Unit
[0103] 312 Frequency Analysis Department
[0104] 313 Abnormality Judgment Department
[0105] AAnalog signal
[0106] A1 Repeating Unit
[0107] B. Rolling bearings
[0108] B1 Outer ring
[0109] B2 Inner ring
[0110] B3 Rotating body
[0111] D Digital signal
[0112] D1 sampling waveform
[0113] D2, D3 envelope waveform
[0114] D4 Analysis target waveform
[0115] D5 analysis value
[0116] F1 First frequency
[0117] Fr repetition frequency
[0118] Fs Sampling frequency
[0119] M Motor
[0120] Tr Repeat period
[0121] Ts Sampling period
[0122] Z1 First interval
[0123] Z2 second interval.
Claims
1. A vibration detection device, characterized in that: include: a vibration detecting unit that detects vibration generated in the rolling bearing and converts it into an analog signal; and a sampling unit for sampling the analog signal and converting it into a digital signal, The vibration is a vibration whose repetitive unit repeats at a predetermined repetitive period when the rolling bearing is damaged, wherein the repetitive unit includes a first vibration interval vibrating at a predetermined first frequency and a second interval following the first vibration interval, The sampling unit samples the analog signal at a sampling frequency lower than twice the first frequency.
2. The vibration detection device according to claim 1, characterized in that: The sampling period is shorter than 1 / 2 of the repetition period.
3. An anomaly detection auxiliary system, characterized in that: include: A digital signal acquisition unit that acquires the digital signal from the vibration detection device according to claim 1 or 2; an envelope detection unit for detecting an envelope of a vibration waveform based on the digital signal; and A frequency analysis unit performs frequency analysis on the envelope to calculate an analysis value for each frequency component.
4. The abnormality detection auxiliary system according to claim 3, characterized in that: The system further includes an abnormality determination unit that determines that an abnormality occurs when the magnitude of the analysis value of each frequency component exceeds a reference value preset within a reference frequency range, wherein the reference frequency range is a frequency range including a repetition frequency that is an inverse of the repetition period.
5. The abnormality detection auxiliary system according to claim 4, characterized in that: The reference frequency range includes an outer ring frequency range set corresponding to the outer ring of the rolling bearing, The abnormality determination unit determines that the outer race is abnormal when the magnitude of the analysis value of each frequency component exceeds the reference value within the outer race frequency range.
6. The abnormality detection auxiliary system according to claim 4, characterized in that: The reference frequency range includes an inner ring frequency range set corresponding to the inner ring of the rolling bearing, The abnormality determination unit determines that the inner race is abnormal when the magnitude of the analysis value of each frequency component exceeds the reference value within the inner race frequency range.
7. The abnormality detection auxiliary system according to claim 3, characterized in that: Also included is the vibration detection device.
8. A vibration detection method, characterized in that: include: A vibration detection process that detects vibration generated in the rolling bearing and converts it into an analog signal; and a sampling step of sampling the analog signal and converting it into a digital signal, When the rolling bearing is damaged, the vibration is repeated in a repetitive unit at a predetermined repetitive period, wherein the repetitive unit includes a first vibration interval vibrating at a predetermined first frequency and a second interval following the first vibration interval. In the sampling step, the analog signal is sampled at a sampling frequency lower than twice the first frequency.
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