JP2003065839A - Method and device for monitoring vibration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow objective determination for proper replacement timing of a bearing, in particular, the determination for the replacement timing of the bearing under inverter control. SOLUTION: After taking out vibrations generated from a rotating part 1 as acceleration signals, only the acceleration signals in medium-high-frequency areas are selected, the each selected acceleration signal is converted into a velocity signal, and an alarm is issued to execute a prescribed action for the rotaing part 1 when a vibration velocity level computed based on the velocity signal exceeds prescribed notification level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention senses the vibration of a rotating portion to constantly grasp the situation of the rotating portion, and the bearing of the rotating portion is neither too early nor too late against damage. The present invention relates to a monitoring method and an apparatus thereof that can replace the bearing at a time when it is not.

[0002]

2. Description of the Related Art Bearings used in rotating parts of all industrial products, including air conditioners such as fans, pumps, refrigerators, and cooling towers, and their motors, gradually deteriorate over time and are damaged. In the old days, an operator, in a daily inspection, listened to the sound made by the rotating bearing, empirically determined the degree of deterioration of the bearing, and replaced it as necessary. With this method, it was not possible to perform objective equipment diagnosis because it relied heavily on individual differences and skill levels.

Therefore, in the conventional method, attention is paid to a vibration state in a low frequency region (generally, a region of 100 Hz or less) such as a primary component or a secondary component of the vibration generated by the rotating part of the equipment, and the frequency is analyzed. I was trying to predict the situation of that part. However, although the failure that can be detected in the low frequency region can be detected with a large vibration such as unbalance of the rotating body and misalignment of the joint portion, it is possible to detect a minute failure such as damage of the bearing. The detection could not be detected by frequency analysis in the low frequency region by sensing the vibration acceleration.

In addition, a large number of recent industrial products employ an inverter control in which the rotation speed is changed according to the state of use. When the inverter control is performed,
The spectrum in the low-frequency region changes drastically in accordance with the change in the number of revolutions, and in many cases it is judged as abnormal even in normal operation by frequency analysis of the sensing data against the standard spectrum and likelihood calculation by automatic judgment by computer. Vibration monitoring of the upper inverter control was difficult.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and it is conventional to detect the damage of the bearing and deal with it, and particularly to objectively determine the proper replacement timing of the bearing. The object of the present invention is to develop a vibration monitoring method and an apparatus therefor capable of objectively diagnosing a rotating part of the apparatus, which was not possible with the above method.

[0006]

The vibration monitoring method described in "claim 1" is a simple method using "speed level" (FIG. 1).
In `` After extracting the vibration generated from the rotating part (1) as an acceleration signal, select only the acceleration signal in the middle and high frequency range, convert this selected acceleration signal into a speed signal, and based on this speed signal When the calculated vibration velocity level exceeds a predetermined warning level, an alarm is issued so as to perform a predetermined action on the rotating part (1). "

The vibration monitoring method described in "Claim 2" relates to the improvement (Fig. 2) of "Claim 1", in which "the vibration generated from the rotating portion (1) is taken out as an acceleration signal, and then the medium / high frequency region is obtained. Vibration signals calculated based on the selected acceleration signal in the high-frequency region while converting the selected acceleration signal into a velocity signal and selecting only the acceleration signal in the high-frequency region from the acceleration signal. After the acceleration level exceeds the warning level, when the vibration speed level calculated based on the speed signal exceeds the predetermined warning level, an alarm is issued to take a predetermined action on the rotating part (1). It is characterized by

Generally, when the bearing (1a) mounted on the rotating portion (1) is damaged, it appears as an increase in vibration acceleration level in the high frequency region (at the stage of FIG. 5, the vibration of FIG. (See the acceleration / vibration velocity level graph). At this point, the bearing (1a) is slightly damaged and can be suppressed only by injecting grease. However, when this gradually grows, it appears as an increase in the velocity of the middle and high frequency vibration velocity components (see FIGS. 7 (b) to 7 (i) at the stage of FIG. 5). On the other hand, as mentioned above, failures such as unbalance of the rotating body and misalignment of the joint part accompanied by large vibration and inverter control appear in the low frequency region such as the first-order component or the second-fourth component of the vibration velocity level. However, it does not appear in the middle and high frequency regions (not shown). Also, when the bearing (1a) is completely damaged, the same phenomenon as misalignment occurs (see FIG. 12 at the stage of FIG. 5). Therefore, the low-frequency region is cut in advance, and when the increase in the vibration velocity level in the medium-high frequency region of 400 to 1 kHz exceeds the preset warning level, the predetermined treatment for the rotating portion (1) is performed. By issuing an alarm as if to apply
It is possible to objectively detect the replacement time of the bearing (1a) of (1).

Further, the damage of the bearing (1a) first appears as an increase in the vibration acceleration level in the high frequency region as described above. Therefore, if there is a rise in the vibration velocity level in the middle and high frequency regions after this rise in the vibration acceleration level, it is possible to determine with high probability that the bearing (1a) is damaged, and When the vibration velocity level in (1) exceeds the preset warning level, it is possible to more objectively detect the replacement time of the bearing (1a).

"Claim 3" relates to a vibration monitoring method using "velocity likelihood" (Fig. 3), "After extracting vibration generated from the rotating part (1) as an acceleration signal, the acceleration signal is converted into a velocity signal. The frequency signal is converted and frequency-analyzed into a speed-frequency spectrum during daily driving, and the speed likelihood of the speed-frequency spectrum during daily driving is calculated with respect to the standard speed-frequency spectrum during normal driving to calculate the change in speed likelihood. amount
When (α) exceeds the warning level, an alarm is issued to take a predetermined action on the rotating part. "

As described above, when the bearing (1a) attached to the rotating part (1) is damaged and grows, the deviation of the speed spectrum during daily operation from the speed standard spectrum appears in the high frequency region. , Gradually expanding to the medium frequency range, and calculating this to observe the velocity likelihood, the damage of the bearing (1a) appears as the variation (α) of velocity likelihood (see Fig. 8). . On the other hand, as described above, failures such as unbalance of the rotating body (1) and misalignment of the joint part that cause large vibration and inverter control appear in the low frequency region such as the primary component or the secondary component of the vibration. However, it does not appear in the middle and high frequency regions.

Therefore, when the velocity likelihood is calculated for the whole range of the vibration generated from the rotating part (1), the imbalance of the rotating body and the misalignment of the joint part are sound, and the constant speed rotation is performed. In this case, the variation amount (α) of the velocity likelihood per unit time of the sensed velocity frequency spectrum during daily driving is the attention variation amount (for example, the increase amount of the velocity likelihood per 2 hours is 3 dB). If it exceeds, it can be judged that the cause of this change amount is that the damage of the bearing (1a) has grown to some extent, and this is a signal that it is time to replace the bearing (1a), and thus the bearing (1a) ) Can be objectively judged when to replace. As will be described later, when the frequency band to be observed is limited to the middle and high frequency regions, it is possible to eliminate the effects of unbalance of the rotating body, misalignment of the joint portion, inverter control, and the like.

However, although the minute damage of the bearing (1a) appears as a change in the vibration acceleration level as described above,
It does not appear as a change in velocity likelihood. Bearing (1a)
The damage that appears as a change in the speed likelihood is a phenomenon that occurs when the damage to the bearing (1a) becomes large to some extent, and the change amount (α) in the speed likelihood exceeds the warning level. In that case, it will be objectively judged as the time to replace the bearing (1a).

Unlike the preceding claim, "claim 4" uses the vibration monitoring method (Fig. 3) using "1/3 octave band", and after extracting the vibration generated from the rotating part (1) as an acceleration signal, The acceleration signal is converted into a speed signal, and the speed signal is frequency-analyzed to be used as the speed frequency spectrum in daily operation. Each band (B1) (B2) of the one-third octave band of the standard speed frequency spectrum in normal operation The speed level change amount and / or the number of bands in which the speed level change has occurred in each band (B1) (B2) of the one-third octave band of the speed frequency spectrum during the daily operation for When the number of bands in which the level change amount and / or speed level change exceeds the warning level, the rotating part
A warning is issued so as to take a prescribed action against (1). "

Also in this case, the imbalance of the rotating body and the misalignment of the joint portion are sound,
And the constant speed rotation, the amount of change in the velocity level and / or the velocity level with respect to the standard spectrum in each one-third octave band with respect to the total value of the vibration generated from the rotating part (1) Focusing on the number of bands in which the change of the bearing has occurred, generally, if the bearing (1a) is slightly damaged, it is one-third of the velocity frequency spectrum.
It becomes a deviation from the velocity standard spectrum in each band of the octave band, first appears in a certain band in the high frequency region, and gradually expands to the band in the medium frequency region.

This deviation increases with the growth of damage to the bearing (1a) and gradually expands to the lower frequency band. This means that the bearing (1a) is replaced by counting the number of frequency bands that have caused the deviation or by detecting that the deviation of a certain frequency band exceeds the warning level (for example, 40 dB; see Fig. 10). You can know the time objectively. The same applies to this case, but if the observed frequency band is limited to the middle and high frequency regions, the effects of unbalance of the rotating body, misalignment of the joint portion, inverter control, etc. can be eliminated. Like

"Claim 5" relates to an improvement of the vibration monitoring method according to claims 3 to 4, "A acceleration signal in a high frequency region is selected from the acceleration signals extracted from the rotating portion (1), and the acceleration is calculated. When the vibration acceleration level calculated based on the signal exceeds the warning level and at least one of the warning levels is observed, a warning is issued to take a predetermined action on the rotating part. Is issued ".

When the bearing (1a), which is the rotating part (1), is damaged, a change in the vibration acceleration level in the high frequency region first appears as described above. The damage at this point is
It is not fatal and can be repaired to some extent by grease injection, and it is not necessary to replace the bearing (1a) at this point. However, the detection of the acceleration change in the vibration level in this high frequency range means that the bearing (1a) is microscopically damaged, and the microscopic damage will grow in the future to cause the severe damage of the bearing (1a). is doing. Therefore, in the case where the warning level of at least one of claims 3 to 4 is observed after detecting the acceleration change in the vibration level in the high frequency region and temporarily suppressing the increase of the acceleration by the grease injection. Sure bearing (1a)
Can be determined to be due to severe damage to. Therefore, it is possible to know the replacement time of the bearing (1a) more accurately and objectively.

According to a sixth aspect of the present invention, in the vibration monitoring method using the third octave band according to the fourth or fifth aspect, among the respective one-third octave bands, the medium and high frequency bands are included. Select (B1) (B2) ... and select the selected band (B
1) Calculate the speed level change amount and / or the number of bands in which the speed level change occurs in (B2) ..., and the speed level change amount and / or the number of bands in which the speed level change occurs is the warning level. When it exceeds, an alarm is issued so as to perform a predetermined treatment on the rotating part (1). "

This method is based on the rotating part (1) and the total value of vibration.
(Generally, in the case of speed, 10 to 1 kHz) is taken in as speed data, frequency analysis is performed, and then the speed level of each one-third octave band is compared. Area (eg 400-1kH
This is the case of selecting the bands (B1) (B2) ... of z). By limiting the bands to be compared in this way to the mid- and high-frequency regions, it is possible to eliminate the effects of the aforementioned unbalance of the rotating body, misalignment of the joint part, inverter control, etc., and immediately before the bearing (1a) is damaged. It is possible to reliably detect the defective state of.

[0021] "Claim 7" is a case where the bearing (1a) is monitored professionally, and "when the speed signal is used, the speed signal in the middle / high frequency region is selected and used". . As described above, the damage and the growth of the bearing (1a) are caused by the velocity likelihood in the middle to high frequency region or the increase in the amount of velocity level deviation in each band of the one-third octave band and the number of bands causing the deviation. Appears. Therefore, by cutting the low-frequency region velocity signal in the sensing data beforehand, it is possible to remove in advance the effects caused by the unbalance of the rotating body, the misalignment of the joint part, or the change in the rotational speed of the inverter control. Therefore, the measurement result can be specialized due to the bearing (1a). That is, in this case, since the vibration speed in the low frequency region is cut in advance, there is a characteristic that it is not influenced by the change in the rotation speed by the inverter control. This method is also applied to the rotating machine under the inverter control. be able to.

"Claim 8" is the vibration monitoring device (A1) shown in (Fig. 1) "acceleration sensor (2) installed in the rotating part (1)"
Band pass filter (3) that passes only the acceleration signal in the middle and high frequencies from the acceleration signal sensed by
An integrator (4) that integrates the selected acceleration signal and converts it into a speed signal, and calculates the vibration speed level based on the speed signal, and when the vibration speed level exceeds the warning level, the rotating part It is composed of a control unit (9) which issues an alarm so as to take a predetermined action for (1). "

"Claim 9" is the vibration monitoring device (A2) shown in (Fig. 2), and the "acceleration sensor (2) installed in the rotating part (1)".
Band pass filter (3) that passes only the acceleration signal in the middle and high frequencies from the acceleration signal sensed by
Based on the integrator (4) that integrates the selected acceleration signal and converts it into a velocity signal, the bandpass filter (6) that passes only the acceleration signal in the high frequency range, and the acceleration signal in the selected high frequency range. After the vibration acceleration level exceeds the warning level, the vibration acceleration level calculated based on the speed signal, and when the vibration speed level calculated based on the speed signal exceeds the warning level, a predetermined action for the rotating portion (1) is performed. It is composed of a control unit (9) for issuing an alarm so as to perform the above. "

"Claim 10" is the vibration monitoring device (A3) shown in (Fig. 3), and the "acceleration sensor installed in the rotating part (1)".
Bandpass filter that passes the acceleration signal in the specified frequency range from the acceleration signal sensed in (2) (3)
And an integrator (4) that integrates the selected acceleration signal and converts it into a speed signal, and the speed standard of the rotating part during normal rotation from the speed frequency spectrum during daily operation formed by frequency analysis of the speed signal. The reciprocal of the spectrum is added to calculate the speed likelihood of the speed frequency spectrum during daily operation, and when the change rate (α) of the speed likelihood exceeds the warning level, the rotation part
A control unit that issues an alarm to take the prescribed action for (1)
(9) It is composed of and ”. Here, the bandpass filter (3) may pass an entire value of 10 to 1 kHz or a mid to high frequency region of 400 to 1 kHz. In the latter case, the inverter control is performed as described above. Can correspond to.

"Claim 11" is the vibration monitoring device (A) shown in (Fig. 3), and the "acceleration sensor installed in the rotating portion (1)".
Bandpass filter that passes the acceleration signal in the specified frequency range from the acceleration signal sensed in (2) (3)
An integrator (4) that integrates the selected acceleration signal and converts it into a speed signal, a speed frequency spectrum during daily operation formed by frequency analysis of the speed signal, and a speed standard of the rotating portion during normal rotation. The velocity level in each one-third octave band of the spectrum is calculated, and the change amount of the velocity level in each band and / or the number of bands in which the change of the velocity level occurs is calculated, and the change amount of the velocity level or / and When the number of bands in which the speed level has changed exceeds the warning level, the control unit (9) issues an alarm so as to perform a predetermined treatment on the rotating portion. " Also in this case, the bandpass filter (3) is, for example, in the case of passing the entire range of 10 to 1 kHz and in the range of 400 to
There are cases where the medium and high frequencies of 1 kHz are passed through, and in the latter case, it is possible to support inverter control as described above.

"Claim 12" is the vibration monitoring device (A4) shown in (Fig. 4), and the "speed detection circuit (ES) according to claim 10
An acceleration detection circuit (EK) having a bandpass filter (6) that passes only the acceleration signal in the high frequency region of the rotating portion (1) sensed by the acceleration sensor (2) is added, and the control unit (9) is After detecting that the vibration acceleration level calculated based on the acceleration signal exceeds the warning level, when the velocity likelihood variation (α) exceeds the warning level, the rotating part
It is set so that an alarm is issued so as to take a prescribed action for (1). "

"Claim 13" is the vibration monitoring device (A4) shown in (Fig. 4), "The speed detecting circuit (ES) according to claim 11
An acceleration detection circuit (EK) having a bandpass filter (6) that passes only the acceleration signal in the high frequency region of the rotating portion (1) sensed by the acceleration sensor (2) is added, and the control unit (9) is After detecting that the vibration acceleration level calculated based on the acceleration signal exceeds the warning level, the amount of change in the speed level and / or the speed in each band of the one-third octave band of the speed frequency spectrum during daily operation Calculate the number of bands in which the level has changed, and when the amount of change in speed level and / or the number of bands in which speed level has changed exceed the warning level, take the prescribed action for the rotating part (1). It is composed of a control unit (9) for issuing an alarm.

"Claim 14" is an improvement of the vibration monitoring device (A3) (A4) described in (Figs. 3 and 4), and "Velocity band filter (3)"
The selection range of is in the middle and high frequency regions. "
As a result, the influence of the inverter control can be eliminated and the deterioration of the bearing (1a) can be observed, and the replacement time of the bearing (1a) can be objectively determined even for inverter-controlled equipment. .

"Claim 15" is an improvement of the vibration monitoring device (A3) (A4) described in (Figs. 3 and 4). "In the vibration monitoring device (A3) (A4) according to claims 11 to 13, Of the 1/3 octave band, the middle and high frequency bands (B1) (B
2) ... is selected, the change amount of the speed level in the selected band (B1) (B2) ... and / or the number of bands in which the change of the speed level occurs is calculated, and the change amount of the speed level and / or the speed level is calculated. When the number of changed bands exceeds the warning level,
An alarm is issued so as to perform a predetermined treatment on each of the rotating parts 1. "

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described with reference to the illustrated embodiments. The subject of the present invention is a bearing (1a) mounted on the rotating part (1) of any mechanical installation. The devices (A1) to (A4) of the present invention have several patterns ranging from a simple structure to a complicated structure. Since the devices (A1) to (A4) of the present invention are based on digital control, they are represented by digital circuits. In outline, the first embodiment (A1) shown in FIG. 1 is equipped with a bearing (1a) of a mechanical device by a simple method using "speed level" as described in "Claim 1". Accelerometers (2) are installed in the rotating part (1) respectively, but from the acceleration signals sensed by the accelerometers (2), for example, only acceleration signals in the mid- and high-frequency regions of 400 to 1 kHz pass. A bandpass filter (3), an integrator (4) that integrates the acceleration signal to convert it into a velocity signal, an AD converter (5) that digitally converts the output of the integrator (4), A control unit (9) that issues an alarm to replace the bearing (1a) of the rotating part (1) when the vibration speed level calculated based on the selected and digitally converted speed signal exceeds the warning level. It consists of and.

As described above, immediately before the bearing (1a) is broken, the vibration velocity level in the medium to high frequency region of 400 to 1 kHz gradually increases. Therefore, if the vibration velocity level in this region is monitored, it is possible to detect the damage received by the bearing (1a) at a proper time, not too late or vice versa. The rotating part (1) where the bearing (1a) is installed is present everywhere in the mechanical device. When trying to monitor the status of all bearings (1a), it is necessary to attach an acceleration sensor (2) to the rotating part (1) equipped with all bearings (1a), and capture and observe all the speed data. . For continuous observation, one set of speed detection circuit (ES) is required for one acceleration sensor (2), but if you want to make periodic observations, the acceleration sensor (2) and speed The detection circuit (ES) may be connected by a switch device (SW), and the control device (9) may switch the switch device (SW) one after another to intermittently capture the acceleration data of the rotating portion (1). . Figure 1
(a) is an example using a switch device (SW). On the other hand, FIG. 1 (b) shows a case where processing is performed in the control unit (9) except for the acceleration sensor (2) and the AD converter (5). In this case, the built-in switch device (SW) is not used, and the full acceleration sensor (2)
The data may be processed simultaneously in parallel and continuously. Although this point is not shown in FIGS. 3 and 4, it is common throughout the present invention.

The vibration monitoring device (A2) shown in FIG.
When a "vibration acceleration level detection circuit (EK)" is added to, the acceleration signal branched from the acceleration sensor (2) installed in the rotating part (1) passes only the acceleration signal in the high frequency region of 1 kHz or more, for example. Band Pass Filter (6)
And an envelope processing circuit (7) for performing envelope processing on the output of the bandpass filter (6) and an output of the envelope processing circuit (7)
It is composed of an A / D converter (8) for converting and a control unit (9) for calculating speed data and acceleration data. Then, the velocity data and the acceleration data are set by the control unit (9) to a predetermined value for the rotating portion (1) at the time when the vibration velocity level exceeds the warning level after the vibration acceleration level in the high frequency region exceeds the warning level. It is supposed to give an alarm to take action.

As described above, the very slight damage to the bearing (1a) can be found by first increasing the vibration acceleration level in the high frequency region. However, at this point, as shown in Fig. 6, the vibration acceleration level is temporarily lowered by the grease injection, and it is possible to deal with it temporarily, but when the damage gradually increases, it becomes impossible to deal with it by the grease injection, and at the same time, the vibration is increased. The speed level is increasing. Therefore, after the vibration acceleration level exceeds the warning level, when the vibration velocity level exceeds the warning level, this is clearly a sign of the replacement time immediately before the bearing (1a) is damaged, and the bearing (1a) You can objectively know when to replace. Therefore, when this warning is issued, the bearing (1
a) is exchanged. 2 (b) is the same as above, except for the acceleration sensor (2) and A / D converter (5), which is processed in the control unit (9) without using the built-in switch device (SW). From (2), the data may be processed concurrently in parallel.

The vibration monitoring device (A3) shown in FIG. 3 is (a) where the velocity likelihood is calculated in the entire region from the low frequency region to the high frequency region (10 Hz to 1 kHz), and when the change is observed, (b)
When the velocity likelihood is calculated in the middle / high range from the medium frequency range to the high frequency range (400 Hz to 1 kHz) and the change is observed, (c) low frequency range to high frequency range (10 Hz to 1 kHz)
In the whole area up to, each of the one-third octave band (B
1) When calculating the change amount (H) of the speed level in (B2) ... and / or the number of bands in which the change of the speed level occurs, (d)
In the entire range from the medium frequency range to the high frequency range (400 Hz to 1 kHz), each band (B1) (B2) of the one-third octave band of the sensed speed frequency spectrum during daily operation with respect to the standard speed frequency spectrum during normal operation ) ...
In some cases, the amount of change (H) in the speed level and / or the number of bands in which the change in the speed level has occurred is calculated. In either case, the circuit is the same.

Explaining the case of FIG. 3, the output of the acceleration sensor (2) installed in the rotating part (1), the bandpass filter (3) that passes only the acceleration signal of a predetermined band, and the bandpass filter (3). Is integrated and converted into a velocity signal, an AD converter (5) for digitally converting the output of the integrator (S), and a control unit (COMP). An FFT for performing spectrum analysis by multiplying the digital velocity data digitally converted by the AD converter (5) in the control unit (COMP) and taken in the control unit (COMP) by Fourier series.
Circuit (10), data of the rotating part (1) at the time of normal operation is taken in, an inverse filter (11) which stores the reciprocal of the standard spectrum by spectral analysis of this, and the inverse filter (11) is stored in advance. Arithmetic circuit that adds the reciprocal of the standard spectrum to the measured velocity spectrum (JS)
(12), based on the output of the speed likelihood calculation circuit (13) or the calculation circuit (12), the inverse filter (11), etc. that calculates the “speed likelihood” based on the output of the calculation circuit (12) One-third octave band deviation calculation circuit (14) that calculates the deviation of the measured speed level from the standard speed level in each band of the "1/3 octave band" and calculates whether or not the deviation reaches the alarm level And "One-third octave band"
In each band, the number of bands in which the actual speed level deviates from the standard speed level is calculated, and whether the number of bands reaches the alarm level is calculated. ) And a band selection circuit (16) provided as necessary. Incidentally, (17) is a monitor and (18) is a printer.

The band selection circuit (16) is a one-third octave band deviation calculation circuit (14) or a one-third octave band deviation band number calculation circuit (15), and is 400 to 1 kHz from the entire range. It has a function of selecting a band belonging to a high frequency region, and is effective when the band filter (3) is a filter that passes all values.

In the above case, the acceleration sensor (2)
Always senses the rotational vibration of the bearing (1a) mounted on the rotating portion (1) as analog data of acceleration, and allows the band filter (3) to selectively pass only the acceleration data of a predetermined band. Band filter (3) is 10
In the case of an all-bandpass filter that passes acceleration of a frequency of up to 1000 Hz, only acceleration data in this range passes through the band filter (3), which is integrated by the integrator (S) and converted into analog speed data. . Then, the signal is digitally converted by the A-D converter (5) following this and taken into the control unit (9). In the control section (9), frequency analysis is performed by the FFT circuit (19), and 10 to 1 in the arithmetic circuit (12) as described above.
The outputs of the inverse filter (11) of the standard spectrum in the frequency band of 000 Hz are added.

When there is no abnormality in the bearing (1a) and the equipment is operating normally without any abnormality, the above 10
The standard frequency spectrum stored in advance in the inverse filter (11) with respect to the frequency spectrum of the actually measured velocity in the frequency band of 1000 Hz is almost the reciprocal thereof, so that the output of the arithmetic circuit (12) becomes almost zero. Therefore, the control unit (COMP)
Shall be judged to be normal in both cases of "velocity likelihood", "observation of deviation state in any one of the one-third octave bands" or "observation of the number of bands causing the deviation". become. Here, “velocity likelihood”, “observation of a deviation state in any one of the one-third octave bands” and “observation of the number of bands causing the deviation” are described at one time. It goes without saying that it is possible to provide only the function of and measure based on the function. Further, as shown in FIGS. 7 and 9, it is also possible to superimpose an actually measured velocity frequency spectrum subjected to frequency analysis and a velocity frequency spectrum in a normal state, and output them on one monitor screen.
It is also possible to launch in 8), and it is also possible to output these speed levels in each band (B1) (B2) of the 1/3 octave band to the monitor (17) or printer (18). is there.

On the other hand, when an abnormality occurs in the bearing (1a), when the abnormality is extremely minute (Fig. 5).
(State of) appears as an abnormal waveform in the high-order frequency band in the high-frequency region as described above.
At this point, the "velocity likelihood", the "deviation state in any one of the one-third octave bands", or the "number of bands in which the deviation occurs" does not appear. (However, as already mentioned, it appears as a change in the vibration acceleration level. "Refer to the graph plotting the acceleration change in the vibration level in Fig. 6.")

When the damage of the bearing (1a) spreads over time, the higher-order waveform abnormality in the high frequency region gradually spreads to the medium frequency region (state of FIG. 5). The expanded waveform abnormality appears as a change in "velocity likelihood", "deviation state in any one of the one-third octave bands", or "number of bands in which the deviation occurs". See the velocity likelihood trend data in FIG. 8, the velocity frequency analysis result graph in FIG. 9, and the one-third octave band velocity frequency analysis result graphs in FIGS.

In the case of the velocity likelihood, generally, the time (logarithmic scale) from the appearance of the change of the velocity likelihood to the setting level (for example, 20 dB) varies considerably depending on the case.
If the bearing (1a) is actually damaged, the time to reach the warning level is very short. Therefore, when the warning level is reached, there is a case where the bearing (1a) has already been damaged, so the change rate (α) in velocity likelihood exceeds the warning level (for example, an increase of 3 dB per 2 hours). If the bearing (1a) is replaced, it is determined that the economical and realistic replacement time has come and an alarm is issued. The operator follows this warning and the bearing (1a) in question.
Will be replaced.

Similarly, when the "deviation state in any one of the one-third octave bands" reaches the warning level, or "the number of bands causing the deviation"
When the warning level is reached, an alarm will be issued. The worker will replace the bearing (1a) in question according to this warning.

In this case, since the whole range from the low frequency region to the high frequency region is targeted for the calculation relating to the velocity likelihood and the one-third octave band, the standard spectrum is used when the rotational speed is largely changed like the inverter control. In contrast, the waveform in the low frequency region changes significantly, and this appears as a change in velocity likelihood or a band change in the low frequency region.As a result, although the bearing (1a) is normal, the control unit Since (COMP) is judged to be abnormal, it cannot be applied in the case of inverter control.

In the case where the whole range value is sampled, the band selection circuit (16) is applied, and the band filter (3) is selected by selecting the region (middle / high frequency region) to be checked as shown in FIG. The same effect as when using the one for the high frequency region can be realized in the case of observing the one-third octave band.

On the other hand, the band-pass filter (3) adopts a filter that passes only the frequency band (400 to 1 kHz) in the high-frequency region from the medium-frequency region.
(1) When the reciprocal of the velocity standard spectrum in the frequency band from the middle frequency region to the high frequency region is stored in the inverse filter (11) in advance, unlike the case where the whole range value is sampled, inverter control and rotor Since it is not easily affected by balance and misalignment of the joint part, it is said that the calculated change rate of velocity likelihood (α) and the change in the 1/3 octave band are caused by the failure of the bearing (1a). Will be specified. Therefore, when the rate of change (α) in velocity likelihood exceeds the above-mentioned level, or when the velocity level in a band with one-third octave band reaches the warning level, or when there is a deviation from the velocity standard spectrum. When the number of generated bands reaches the attention level, it is immediately judged that the state of the bearing (1a) is just before breakage.

In the case of FIG. 4, in the case of detecting the abnormality of the bearing (1a) more precisely, an acceleration monitoring circuit (EK) for monitoring the change of the acceleration of the vibration level in the vibration monitoring device (A3) described above.
This is the case when is added. As described above, the very early defects of the bearing (1a) do not appear as velocity abnormalities or waveform abnormalities in the higher-order bands of the 1/3 octave band, but they appear as changes in the vibration acceleration level. come. If the vibration acceleration level does not reach the preset warning level (for example, 120 dB; see FIG. 6),
It is assumed that the bearing (1a) is not damaged so that the bearing (1a) is not damaged. When the scratch gradually grows, the vibration acceleration level increases, and the warning setting level (for example, 120 dB) is reached, the personal computer judges that it is time to replenish grease and issues an alarm. By this alarm, the worker replenishes the area with grease. Of course, the grease may be automatically replenished.

As a result, sufficient grease is replenished on the raceway surface of the bearing, and high frequency abnormal vibration is reduced,
The vibration acceleration level in the high frequency range will be below the warning level. However, at this point the bearing (1a) damage is not like immediate replacement, but can be used to some extent by grease injection. However, when such grease replenishment is repeated, the scratches on the bearing (1a) gradually grow, the grease replenishment interval becomes short, and the abnormal vibration thereof also becomes large, gradually expanding to the middle frequency band and the deviation thereof. So, after detecting the acceleration change in this vibration level, as already mentioned,
Amount of change in velocity likelihood over the entire area or in the middle and high frequency regions
(α) or by detecting the velocity level waveform anomaly in the higher order band in the 1/3 octave band,
It becomes possible to determine that the problem location is the bearing (1a). When the above-mentioned symptom appears, the computer determines that it is time to replace the bearing (1a) and issues an alarm. The worker replaces the bearing (1a) at the relevant part according to this warning.

[0048]

The present invention calculates the speed likelihood of the speed frequency spectrum during the daily operation sensed with respect to the standard speed frequency spectrum during normal operation, particularly in the medium and high frequency regions, and calculates the amount of change in the speed likelihood. Exceeds the warning level, or the amount of change in the speed level and / or speed in each band of the one-third octave band of the speed frequency spectrum in the sensed daily operation relative to the standard speed frequency spectrum in normal operation If the number of bands in which the level has changed is calculated and the amount of change in the speed level and / or the number of bands in which the speed level has changed exceeds the warning level, there is an abnormality in the rotating part, that is, immediately before the bearing is damaged. Determining the condition allows the bearings to be replaced at the most appropriate time. in addition,
Since the target of abnormality detection is limited to the middle and high frequency regions,
It is almost unaffected by the influence of inverter control, etc., and it has become possible to detect bearing failures under inverter control, which was previously impossible only with automatic computer judgment. Further, by adding the acceleration signal of the vibration level, it is possible to identify the failure of the bearing among the many failure points of the equipment.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a first embodiment of the device of the present invention.

FIG. 2 is a block circuit diagram of a second embodiment of the device of the present invention.

FIG. 3 is a block circuit diagram of a third embodiment of the device of the present invention.

FIG. 4 is a block circuit diagram of a fourth embodiment of the device of the present invention.

FIG. 5 is a logarithmic graph showing the relationship between the progression of bearing damage and the detected frequency band, acceleration, and displacement.

FIG. 6 Trend graph of vibration level and acceleration / velocity likelihood at the time of initial bearing damage

FIG. 7 is a time change graph of a velocity spectrum until a warning is issued, which is sampled by the present invention.

8 is a velocity likelihood trend graph created by processing the data of FIG. 7.

FIG. 9 is a drawing of a monitor screen on which a standard spectrum and an actually measured spectrum are displayed in an overlapping manner.

FIG. 10 is a 3-octave band graph in which a standard spectrum and an actual spectrum are superposed.

FIG. 11 is a drawing of a monitor screen displaying a 3 octave band graph in which a standard spectrum and an actually measured spectrum are superimposed.

FIG. 12 is a graph showing the relationship between the vibration velocity level and the velocity likelihood and the acceleration likelihood when the bearing is broken.

[Explanation of symbols]

(1) Rotating part

Continued front page    (72) Inventor Shinichiro Hamasaki             133 patent machine, 10-10 Minami-Hatsushima-cho, Amagasaki-shi, Hyogo             Ware corporation (72) Inventor Takuji Sato             2-7-3 Marunouchi, Marunouchi, Chiyoda-ku, Tokyo             Hishijisho Co., Ltd. (72) Inventor Keiichi Maejima             1-1-1 Minamiaoyama, Minato-ku, Tokyo Stock market             Company Mitsubishi Estate design F-term (reference) 2G064 AA17 AB01 AB02 AB07 AB08                       AB22 BA02 CC06 CC13 CC19                       CC26 CC42 CC43 CC46 CC52                       CC62

Claims (15)

[Claims] 1. Extracting vibration generated from a rotating portion as an acceleration signal, selecting only an acceleration signal in a medium / high frequency region, converting the selected acceleration signal into a velocity signal, and based on the velocity signal. A vibration monitoring method, wherein an alarm is issued to take a predetermined action on a rotating portion when the calculated vibration speed level exceeds a warning level. 2. After extracting vibration generated from a rotating portion as an acceleration signal, only the acceleration signal in the middle / high frequency region is selected, the selected acceleration signal is converted into a velocity signal, and the acceleration signal is converted into the high frequency region. Only the acceleration signal of the above is selected, and after the vibration acceleration level calculated based on the selected acceleration signal in the high frequency region exceeds the warning level, the vibration speed level calculated based on the speed signal is changed to the warning level. A vibration monitoring method, which is characterized in that an alarm is issued so that a predetermined treatment is applied to a rotating portion when the temperature exceeds the limit. 3. The vibration generated from the rotating portion is taken out as an acceleration signal, the acceleration signal is converted into a speed signal, and the speed signal is subjected to frequency analysis to obtain a speed frequency spectrum in daily operation, which is used in normal operation. Compute the speed likelihood of the speed frequency spectrum during the daily operation with respect to the standard speed frequency spectrum, and when the amount of change in the speed likelihood exceeds the warning level, issue an alarm to take a predetermined action on the rotating part. Vibration monitoring method characterized by. 4. The vibration generated from the rotating portion is taken out as an acceleration signal, the acceleration signal is converted into a speed signal, and the speed signal is frequency-analyzed to obtain a speed frequency spectrum for daily operation, which is used for normal operation. The amount of change in the speed level and / or the band in which the change of the speed level occurs in each band of the one-third octave band of the speed frequency spectrum during daily operation for each band of the one-third octave band of the standard speed frequency spectrum Calculate the number,
A vibration monitoring method, wherein when the amount of change in the speed level and / or the number of bands in which the change in the speed level exceeds the warning level, an alarm is issued so as to perform a predetermined treatment on the rotating portion. 5. The acceleration signal in the high frequency region is selected from the acceleration signals extracted from the rotating portion, and after the vibration acceleration level based on the acceleration signal exceeds the warning level, the vibration acceleration level exceeds the warning level. A vibration monitoring method, wherein when at least one warning level is observed, an alarm is issued so as to perform a predetermined treatment on a rotating part. 6. A vibration monitoring method using a one-third octave band according to claim 4 or 5, wherein a medium or high frequency band is selected from the respective one-third octave bands. Then, the amount of change in the speed level in the selected band or / and the number of bands in which the change in the speed level occurs is calculated, and the amount of change in the speed level or / and the number of bands in which the change in the speed level exceeds the warning level. The vibration monitoring method is characterized in that an alarm is issued so that a predetermined treatment is applied to the rotating part when the vibration occurs. 7. The vibration monitoring method according to claim 3, wherein when a speed signal is used, a speed signal in a medium / high frequency region is selected and used. 8. A bandpass filter that passes only an acceleration signal in the middle / high frequency range from an acceleration signal sensed by an acceleration sensor installed in a rotating portion, and a selected acceleration signal is integrated and converted into a velocity signal. And a control unit that calculates a vibration velocity level based on the velocity signal and issues an alarm to take a predetermined action on the rotating portion when the vibration velocity level exceeds the warning level. A vibration monitoring device characterized in that 9. A bandpass filter that passes only an acceleration signal in the middle / high frequency range from an acceleration signal sensed by an acceleration sensor installed in a rotating portion, and a selected acceleration signal is integrated and converted into a velocity signal. An integrator, a bandpass filter that passes only the acceleration signal in the high frequency region, and a vibration acceleration level is calculated based on the selected acceleration signal in the high frequency region, and after the vibration acceleration level exceeds the warning level, A vibration monitoring device, comprising: a control unit for issuing an alarm so that a predetermined measure is applied to a rotating portion when a vibration speed level calculated based on the speed signal exceeds a warning level. 10. A bandpass filter for passing an acceleration signal in a predetermined frequency region from an acceleration signal sensed by an acceleration sensor installed in a rotating portion, and an integration for integrating a selected acceleration signal and converting it into a velocity signal. And the reciprocal of the speed standard spectrum of the rotating part during normal rotation is added from the speed frequency spectrum during daily operation formed by frequency analysis of the speed signal, and the speed likelihood of the speed frequency spectrum during daily operation is calculated. A vibration monitoring device comprising a control unit for issuing an alarm so as to take a predetermined action on a rotating portion when the amount of change in speed likelihood exceeds a warning level. 11. A bandpass filter for passing an acceleration signal in a predetermined frequency range from an acceleration signal sensed by an acceleration sensor installed in a rotating portion, and an integration for integrating a selected acceleration signal and converting it into a velocity signal. And the speed level in each band of the one-third octave band of the speed frequency spectrum in daily operation formed by frequency analysis of the speed signal and the speed standard spectrum of the rotating portion in normal rotation, and each band is calculated. When the amount of change in the speed level or / and the number of bands in which the change of the speed level occurs is calculated, and the number of bands in which the change of the speed level or / and the change in the speed level exceeds the warning level, the rotating part And a control unit for issuing an alarm so as to perform a predetermined treatment on the vibration monitoring device. 12. The speed detection circuit according to claim 10,
An acceleration detection circuit having a bandpass filter that passes only the acceleration signal in the high frequency region of the rotating portion sensed by the acceleration sensor is added, and the vibration acceleration level calculated by the control unit based on the acceleration signal is the warning level. A vibration monitoring device, which is set to issue an alarm so that a predetermined measure is applied to a rotating part when the velocity likelihood change amount exceeds a warning level after it has been detected. 13. The speed detection circuit according to claim 11,
An acceleration detection circuit having a bandpass filter that passes only the acceleration signal in the high frequency region of the rotating portion sensed by the acceleration sensor is added, and the vibration acceleration level calculated by the control unit based on the acceleration signal is the warning level. After detecting that the speed is exceeded, the amount of change in the speed level in each one-third octave band of the speed frequency spectrum during daily operation or / and the number of bands in which the speed level has changed are calculated, and the speed level Amount of change or /
And a controller for issuing an alarm so as to take a predetermined action on a rotating part when the number of bands in which the speed level has changed exceeds the warning level. 14. The selection range of the velocity band filter is medium.
The vibration monitoring device according to claim 10, wherein the vibration monitoring device is in a high frequency region. 15. The vibration monitoring device according to claim 11, wherein a band in the middle / high frequency region is selected from each band of the one-third octave band, and the change amount of the velocity level in the selected band or / And calculate the number of bands in which the speed level has changed, and when the amount of change in the speed level and / or the number of bands in which the speed level has changed exceed the warning level, take the prescribed action for the rotating part. Vibration monitoring device characterized by issuing an alarm to.