JPH0125013B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a rotating body abnormality detection device for detecting an unbalanced state of a rotating body device.

In general, maintaining a good balance of the rotating body of various rotating body devices is very important in extending the life of the bearings of the rotating body and improving rotational performance. And once,
When measuring the unbalanced state of the rotating body after the rotating body device has been installed on the foundation of a building or other machinery, conventionally, an acceleration sensor or the like is attached to the rotating body device, and the signal from this acceleration sensor is measured using a vibration meter. It is amplified by the amplifier built in etc., and the acceleration (mm/
sec ² ) or velocity (mm/sec), and then the root mean square value (rms) of this acceleration or velocity was determined as the vibration level. Then, based on the magnitude of the absolute value of this root mean square value (rms), it was determined whether the balance state of the rotor body was "normal" or "abnormal."

However, the above-mentioned apparatus that evaluates the balance state of the rotating body body from the absolute value of the vibration level has the following problems.

That is, the vibration level appearing on the outer surface of the rotating body device varies greatly depending on the foundation of the rotating body device itself or the installation conditions on other machines. For example, if the device is fastened to the foundation with anchor bolts or the like, the vibration level will be low, and if it is attached via a vibration isolating material such as rubber, the vibration level will be high. Therefore, even if the amount of unbalance of the rotating body body is constant, there is a large difference in the measured vibration level, making it difficult to accurately grasp the balanced state of the rotating body body. As a result, it is not possible to accurately correct the balance of the rotating body.
There were problems such as shortened bearing life and decreased rotational performance.

In order to avoid the above-mentioned problems, the ISO standard requires that the measured The permissible vibration level is set in several stages.

However, in the method of this ISO standard, it is necessary to determine the tolerance level in advance, which is determined by the installation conditions, the size of the rotating body device, etc. Also,
Strictly speaking, this tolerance level also differs for each rotating body device. Therefore, there has been a problem in that the result of determining whether the balance state of the rotating body of the rotating body device is "normal" or "abnormal" is not always accurate.

The present invention has been made based on these circumstances, and its purpose is to easily and accurately determine the balance state of a rotating body device from the measured vibration waveform. An object of the present invention is to provide a rotating body abnormality detection device capable of detecting an unbalanced state of a rotating body main body.

According to the present invention, the vibration waveform of a vibration detector using an acceleration sensor or the like attached to a rotating body device is determined depending on whether the balance state of the rotating body is “normal” or “abnormal”.
As specifically described below, the present invention focuses on the fact that not only the amplitude but also the waveform is greatly different, and an unbalanced state of the rotating body of the rotating body device is detected.

In other words, when the unbalance amount of the rotating body body is below a certain limit, that is, when the balance state is good, the vibration waveform not only has a small absolute value of the amplitude A but also a waveform as shown in FIG. 1a. contains miscellaneous frequency components. Therefore, this vibration waveform becomes close to a random noise waveform, and the density distribution of half amplitude of the waveform becomes a substantially normal distribution as shown in FIG. 2a.

On the other hand, when the unbalance amount of the rotating body body exceeds a certain limit, that is, when the balance state is poor, the vibration waveform not only has a large absolute value of the amplitude A but also a vibration waveform, as shown in FIG. 1b. A frequency component corresponding to the rotation speed appears in the waveform itself.
Therefore, this vibration waveform becomes almost a sine waveform, and the density distribution of half amplitude of the waveform has a maximum value of the density distribution at a position close to the amplitude value of the sine function, as shown in Figure 2b. It becomes a shape.

Therefore, in order to determine whether the balance state of the rotating body is "normal" or "abnormal", it is sufficient to detect the difference between the two density distributions in FIG. 2a and b. In the present invention, the ratio between the amplitude (peak A) indicating the maximum value (max) of each density distribution and the average value of the amplitude (AVE) is compared, and if this ratio exceeds a certain limit value, the rotation This is to determine that the balance state of the body is abnormal.

For example, in the balance state shown in Figure 2a,
As for the ratio between Peak A and AVE, since Peak A is almost close to 0, the value of this ratio is also close to 0.
In the unbalanced state shown in Figure 2, assuming that the signal is a sine wave, PeakA/AVE = π/2 = 1.57, so these are the values used to determine whether the rotating body is "normal" or "abnormal" in its balanced state. A value intermediate between the two values is used.

FIG. 3 is a block diagram showing a schematic configuration of a rotating body abnormality detection device according to an embodiment of the present invention.

In the figure, 1 is a vibration meter that detects vibrations of a rotating body device (not shown), including a vibration detector 1A and an amplifier 1B.
It consists of The output signal output from this vibration meter 1 is A/D converted at a predetermined sampling frequency by an A/D converter 2, and the signal data of the absolute value of the output signal is a signal made up of n comparators 3. Input into separator. Each comparator 3 is a window type comparator that outputs a digital signal to its output terminal only when a signal in a preset level region (range) is input. The signal levels A(i) of each comparator 3 are set to increase in numerical order. A respective counter 4 is connected to each output terminal of these comparators 3, and counts the digital signals outputted from each of the comparators 3. Then, the output of each counter 4 is input to an adder circuit 5, which calculates a total value Σ representing a weighted total value of the density distribution shown in FIG. 2a and b.
This total value Σ is input to the average value calculation circuit 6.
The average value calculation circuit 6 calculates the average value AVE of the signal level (amplitude) of all signal data from the total number N of data counted by the counter 7 connected to the output terminal of the A/D converter 2 and the above-mentioned total value Σ. seek. on the other hand,
A Peak·A detection circuit (maximum signal level detection circuit) 8 is connected to each counter 4, and Peak·A shown in FIGS. 2a and 2b is determined here. 9 is a division circuit which calculates the ratio between Peak·A and AVE and sends it to the determiner 10. The determiner 10 compares the above (Peak·A/AVE) value with a preset value.

Next, the operation of the rotating body abnormality detection device configured as described above will be explained according to the flowchart of FIG. 4.

First, after starting the program, at P1, the count value CTR T of the counter 7 and each count value CTR1 to CTR _o of the counter 4 are cleared to zero,
Subsequently, at P2, one piece of vibration signal data sampled by the A/D converter 2 is input to each comparator 3. Then, the comparator of the signal level (amplitude) A(i) of the input signal data at P3
A signal is output from COMP(i), and the count value CTR(i) of the counter 4 connected to this comparator COMP(i) is incremented by one at P4.
Next, at P5, the count value CTR T of the counter 7 that counts the total number of data N is incremented by one, and at P6, the count value CTR T is increased by one.
It is determined whether or not the total number of data has reached N, and if it has not reached it, the process returns to P2 and data is read again. At P6, if the count value CTR T reaches the predetermined total number of data N, reading the data is stopped,
An adder circuit 5 calculates the total value Σ.

That is, after clearing the address pointer i of n counters and the total value Σ to zero at P7,
At P8, a subtotal value Σ(i) is determined as the product of the count value CTR(i) of each counter and the input signal level (amplitude) A(i) of the comparator COMP(i) corresponding to this counter. Next, in P9, the above subtotal value Σ
After adding (i) to the total value Σ, the address pointer is incremented by one i at P10. Then, in P11, it is determined whether i=n, that is, whether or not the total has been completed for all counters 4. If not, the subtotal value is calculated again in P8. When the summation is completed in P11, in P12, the average value calculation circuit 6 of FIG.
Divide by the total number of data N to calculate the average value AVE of the amplitude of all signal data.

Next, the amplitude (Peak·A) indicating the maximum value (max) of the density distribution in FIGS. 2a and 2b is determined.

That is, after clearing the amplitude (Peak A), the count value of the counter indicating the maximum count value (CTRMAX), and the address pointer i to zero in P13, the count value is cleared in P14.
Compare CTR(i) and maximum count value CTRMAX, and if CTR(i)>CTRMAX, at P15
In addition to replacing CTRMAX with CTR(i), Peak・
Replace A with A(i) and proceed to P16. Also, P14
If CTR(i)<CTRMAX, go directly to P1
Proceed to step 6. At P16, address pointer i
After counting up by 1, at P17, i
=n, that is, it is determined whether or not the search for the maximum value has been completed for all the counters 4. If not, the process returns to P14 and the search is performed again. When the search for the maximum value Peak・A is completed in P17, the ratio between Peak・A and the average value AVE obtained in P12 is determined in P18, and it is determined in P19 whether this ratio is smaller than 1. However, if it is smaller than 1, the density distribution is as shown in FIG. On the other hand, if it is larger than 1, the density distribution is as shown in FIG. 2b in P21, so the balance state of the rotating body is determined to be "abnormal".

In a rotating body abnormality detection device having such a configuration, whether the balance state of the rotating body body is "normal" or "abnormal" is determined based on the shape of the density distribution of the vibration waveform, that is, the content rate of the primary waveform component of the vibration waveform. ing.
In this way, since the absolute value of the signal level of the vibration waveform is not used as a means of determining whether the balance state is good or bad, the balance state of the rotating body body can be determined regardless of the installation conditions of the rotating body device, the size of the rotating body device, etc. ``normal'' and ``abnormal'' can be accurately and easily determined in a short time. As a result, by correcting the balance of the rotating body body at the optimum time, it is possible to extend the life of the bearing portion and improve rotational performance.

Note that in the present invention, instead of using the input signal (amplitude) level Peak A of the comparator connected to the counter indicating the maximum count value, the maximum value level Max A of the input signal (amplitude) may be used. .

That is, if the density distribution in FIG. 2a is approximately a normal distribution, and if the standard deviation of this normal distribution is σ, then the ratio between the maximum value Max·A and the average value AVE is approximately expressed by the following equation.

Max·A/AVE=3σ/0.67σ≈4.5 On the other hand, assuming that the waveform shown in FIG. 2b is a sine wave, the ratio between the maximum value Max·A and the average value AVE is roughly expressed by the following equation.

Max・A/AVE=π/2≒1.57 Therefore, if the above ratio is, for example, 3 or more, the balance state of the rotating body body is determined to be “normal,” and if it is 3 or less, it is determined to be “abnormal.” do it.

In this case, the rotating body abnormality detection device is the third
In the figure, the Peak/A detector 8 may be replaced with a Max/A detector. The operation of this device is shown in the flowchart of FIG. 4 by the average value of P12.
After finding AVE, the flow will look like the flow chart in Figure 5.

That is, after determining the average value AVE in P12, in Q1, the maximum amplitude value Max·A is cleared to zero, and the address pointer i is set to the maximum value n (i=n). That is, the signal level (amplitude) A
Search from high to low (i). Next, Q
In step 2, it is determined whether the count value CTR(i) of the counter is zero, and if it is zero, the address point is counted down by 1 in Q3, and then the count value is transferred to the counter whose signal level is one level lower in Q2.
It is determined again whether CTR(i) has occurred. Then, when the count value CTR(i) is generated in the counter, the signal level (amplitude) A(i) of the counter at that time is set to the maximum amplitude value Max・A in Q4, and Q5
Find the ratio between Max A and AVE obtained in P12, and determine in Q6 whether this ratio is greater than 3. If it is greater than 3, the density distribution is as shown in Figure 2 a, so in Q7 Therefore, the balance state of the rotating body body is determined to be "normal." On the other hand, if it is smaller than 3,
In Q8, since the density distribution is as shown in FIG. 2b, the balance state of the rotating body body is determined to be "abnormal".

Even with the rotating body abnormality detection device configured in this manner, it is possible to obtain the same determination results as in the above-described embodiment, and therefore, the same effects as in the above-described embodiment can be obtained.

Note that the present invention is not limited to the embodiments described above. In the example, Peak・A and
Set the limit value of the ratio to AVE as 1, and set Max・A and
Although the limit value of the ratio to AVE is set to 3, the set value of these limit values may be slightly changed depending on the measurement conditions, the installation conditions of the rotating body device to be measured, etc. Further, a limit value for the ratio between Peak·A and the RMS value may be set, or a limit value for the ratio between Max·A and the RMS value may be set.

As described above, according to the present invention, whether the balance state of the rotating body body is "normal" or "abnormal" is determined based on the shape of the density distribution of the vibration waveform. Therefore, since the absolute value of the signal level of the vibration waveform is not used as a means of determining whether the balance condition is good or bad, the rotation body's It is possible to provide a rotating body abnormality detection device that can accurately and easily determine whether the balance state is good or bad in a short time.

[Brief explanation of drawings]

Figure 1 a and b are vibration waveform diagrams of the rotating body device, Figure 2
Figures a and b are density distribution diagrams of the same waveforms, Figure 3 is a block diagram showing the schematic configuration of a rotating body abnormality detection device according to an embodiment of the present invention, and Figure 4 shows the operation of the rotating body abnormality detection device. Flowchart FIG. 5 is a flowchart showing part of the operation of a rotating body abnormality detection device according to another embodiment of the present invention. 1... Vibration meter, 1A... Vibration detector, 2...
A/D converter, 3... Comparator, 4, 7...
Counter, 5... Addition circuit, 6... Average value calculation circuit, 8... Peak/A detection circuit, 9... Division circuit,
10...Judgment device.

Claims (1)

[Scope of Claims] 1. Vibration detection means for detecting vibrations of a rotating body device and outputting a signal corresponding to the vibrations; Sampling means for sampling output signals from the vibration detection means; Respectively different predetermined input signals; a plurality of comparators each having a level region, receiving the signal output from the sampling means, and outputting a signal when the level thereof reaches a different predetermined input signal level region; a plurality of counters each counting the number of outputs; an addition means for summing the products of each count value of the plurality of counters and a predetermined signal input level corresponding to the plurality of counters for all the counters; the addition means average value calculating means for calculating the average value of the signal levels of all the output signals by dividing the total value outputted from the sampling means by the total number of times the sampling means samples; the highest value indicating the maximum count value among the plurality of counters; maximum signal level detection means for detecting a counter and outputting the predetermined input signal level corresponding to the maximum counter; dividing the maximum signal level output from the maximum signal level detection means by the average value of the signal levels; A rotating body abnormality detection device comprising: a dividing means; and a determining means for determining that the rotating body device is in an abnormal state when the division value obtained from the dividing means is equal to or greater than a predetermined value. 2. Vibration detection means for detecting the vibration of the rotating body device and outputting a signal corresponding to the vibration; Sampling means for sampling the output signal from the vibration detection means; Each having different predetermined input signal level regions; , a plurality of comparators that receive the signals output from the sampling means and output signals when their levels reach different predetermined input signal level regions; receive the output signals of the comparators and count the number of outputs, respectively; a plurality of counters; an addition means for summing the products of each count value of the plurality of counters and a predetermined signal input level corresponding to the plurality of counters for all the counters; and a sum output from the addition means. average value calculation means for calculating the average value of the signal levels of all the output signals by dividing the value by the total number of times the sampling means samples; detecting the maximum signal level of the output signals output from the sampling means; a maximum signal level detection means for dividing the maximum signal level output from the maximum signal level detection means by an average value of the signal levels; a division value obtained from the division means is a predetermined value; A rotating body abnormality detection device, comprising: determining means for determining that the rotating body device is in an abnormal state in the following cases.