JPS5997017A - Inspector for equipment with sound or vibration - Google Patents

Abstract

PURPOSE:To enable accurate detection of deficiency even for an intermittent defective component where the frequency spectrum from an object to be inspected varies instantaneously by determining the variation with time of the frequency spectrum in terms of frequency components of the spectrum to be compared with a reference value. CONSTITUTION:A noise of a motor 1 is taken into a frequency analyzer 10 through a microphone 2 and an amplifier 3 to apply a spectrum A to a standard deviation computing unit 20 corresponding to the noise. The computing unit 20 determine a standard deviation within a fixed time in terms of frequency components of the spectrum A and a standard deviation vector E in terms of frequency components is applied to a differential device 11. At the same time, a signal (a reference vector F) of a reference memory 12a is applied to the differential device 11 with which a deviation obtained by subtracting the reference vector F from the standard deviation vector E is applied to an totalizer 14 through a non-negative circuit 21. Deviation portions are totalized with an totalizer 14 which provides a total sum G to a discriminator 15. The discriminator 15 compares the total sum G with the set value and judges that the motor works well when the total sum G is below the set value. It judges that the motor is poor in its nature when it exceeds the set value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for inspecting equipment using sound or vibration, which detects sound or vibration generated during operation of equipment and determines whether the equipment is in good condition.

FIG. 1 is a block diagram showing the configuration of a conventional device of this type together with an object to be inspected, which specifically uses sound to determine the quality of equipment. In other words, the motor as the object to be inspected (
1) Converts the noise into an electrical signal using a microphone (2), amplifies this electrical signal with an amplifier (8), applies it to a pass/fail judgment section (4), and displays the judgment result on a display (5). It is.

Here, the pass/fail determining section (4) includes a frequency analyzer for determining the frequency spectrum A1 of the electrical signal sent through the amplifier (8), that is, the intensity distribution of the frequency components of the sound, and a frequency analyzer that receives this frequency spectrum A. , input the reference spectrum B of the reference memory 4 in which the frequency spectrum (or design data) of a motor of the same type as motor (1) and with good properties is registered in advance, and compare these to determine the difference in frequency classification. Absolute value circuit (1
B) and the sum of all frequencies by accumulating these absolute deviations (
An accumulator α lead that calculates the deviation amount C (hereinafter referred to as the deviation amount), a judger (15J) that determines whether the deviation amount C exceeds a preset value or not, and a judgment device (15J) that associates each of these components. and a control circuit 06) for operating the control circuit 06).

Therefore, when an electric signal corresponding to the noise of the motor (1) is applied to the pass/fail judgment section (4), the frequency spectrum A and the reference spectrum B of -F: are compared, and the distribution including the level is determined to be defective. The difference is determined as a deviation amount C, and when this deviation amount C is less than or equal to a set value, the motor (1) is judged to be in good condition, and when this deviation amount C exceeds the set value, the motor (1) is judged to be in poor condition. It is determined that

The frequency spectrum of a motor with good properties that is registered in the memory as reference spectrum B is the frequency spectrum of the motor with the best performance, or the average value of the frequency spectra of a large number of motors that are considered to be of good quality. Regardless of which of these is adopted, the same quality determination can be made by appropriately determining the quality determination level set in the determiner (to).

FIGS. 2(a) and 2(b) are diagrams simultaneously showing the frequency spectrum of the motor (1) in the frequency analyzer and the reference spectrum registered in the reference memory. As in a), when the frequency spectrum A indicated by the solid line and the reference spectrum B indicated by the broken line are similar, the value of the deviation amount C corresponding to the area of the diagonal line, that is, the deviation between the two curves, is small. (9) From this, it is determined that the motor (1) is in good condition.

In addition, as shown in (1)), if a large intensity difference occurs locally between the frequency spectrum A shown by the solid line and the reference spectrum B shown by the broken line, the area of the shaded part The deviation amount CO value corresponding to becomes large, and as a result, the motor (1) is determined to be defective as there is some kind of abnormality.

In addition, if the relationship between the type of abnormality to be inspected and the frequency spectrum is clear from past experience and knowledge, weighting may be done by frequency, the sum of the squares of the frequency bottom fractional deviation, or alternatively, the frequency spectrum may be weighted. Excluding the deviation where spectrum A is /JS smaller than reference spectrum B,
By accumulating only the deviations in the portion where the frequency spectrum A is larger than the reference spectrum B, more accurate pass/fail determination can be performed.

In this way, the quality of the motor (1) to be inspected is automatically determined, and the inspection can be made more efficient and accurate.

Further, by attaching a vibration meter to the wall of the object to be inspected instead of the microphone (2), it is possible to judge the quality of the equipment by vibration in the same manner as described above.

Such conventional inspection equipment is configured to calculate the amount of deviation between the frequency spectrum of the subject to be inspected and the reference spectrum and determine pass/fail based on the magnitude of the deviation. By determining the average amount of deviation within a unit time, highly accurate pass/fail judgment is possible. However, the frequency spectrum of the test target during actual operation often changes slowly and greatly over time, and the amount of deviation obtained by accumulating deviations from the X quasi-spectrum also includes the deviation due to changes over time. For example, even if a bearing is contaminated with foreign matter and becomes defective for a short period of time, and the resulting defective frequency component momentarily increases, averaging operations can reduce the instantaneous abnormal component. Become,
Since the amount of deviation increases only slightly, this is considered to be a change due to the passage of time, and as a result, there is a drawback that defect detection cannot be performed.

The present invention has been made to eliminate the drawbacks of the conventional ones described above, and the tuning fork to be inspected generates a defective sound only instantaneously based on the amount of time change in the vibration frequency spectrum. The purpose of the present invention is to provide an equipment inspection device using sound or vibration that can reliably detect any equipment failure.

The present invention will be described below with reference to the accompanying drawings. First, FIG. 3 is a block diagram showing the configuration of a tuning fork or vibration device inspection apparatus according to the first aspect of the present invention, and the same reference numerals as in FIG. 1 indicate the same elements. Then, between the frequency analyzer (10) and the difference device, a standard deviation vector is added between the frequency analyzer (10) and the difference device, which serves as a change amount calculator that calculates the amount of time change of the frequency components of the frequency spectrum within a certain time for each frequency component. In Figure 1, the frequency spectrum of a motor with good properties is registered in the reference memory.

Here, the reference memory (12''a) is used as a change amount setter that registers the amount of time change within a certain period of time of the frequency component of a long-lasting device for each frequency component.

The difference from FIG. 1 is that, instead of the absolute value circuit (1B) in FIG. 1, a non-negative circuit (211) that allows only the positive signal output from the difference device (11) to pass is used. .

The tuning fork of the present invention constructed as described above will be described below with reference to the fourth section of the operation of the equipment inspection device using vibration. The microphone (2) converts it into an electric number 100, which is taken into a frequency analyzer through an amplifier (8) and analyzed for frequency, and the frequency spectrum A corresponding to the noise of the motor (1) is converted into a standard one after another. Added to deviation calculator ■. In the standard deviation calculator)), the standard deviation within a certain time is determined for each frequency component of the frequency spectrum A, and the standard deviation vector E for each frequency is added to the difference unit α force. At this time, the difference device α contains the reference memory (12a) No. 100,
That is, the reference vector F corresponding to the standard deviation in the long-duration device is added! 11. The deviation obtained by subtracting the reference vector F from the standard deviation vector E is the non-negative circuit (2
11 to the accumulator (14i).

Therefore, the deviations for frequencies where the standard deviation vector E is larger than the reference vector F- are accumulated by the accumulator C141, and the sum value G is added to the determiner (total). The determiner side compares this total value G with the set value set here in the same manner as described above.

When the sum value G is less than or equal to the set value, it is determined that the motor (1) is in good condition, and when the sum value G exceeds the set value, it is determined that the motor (1) is in poor condition.

Incidentally, the cycle for determining the vcm standard deviation of the frequency spectrum by number of limbs is appropriately determined in consideration of the time variation of the frequency differential spectrum of the object to be inspected.

FIG. 4(a) and +bi are the standard deviation vectors of the frequency bottom separation within a certain time of the frequency components of the motor (1).

In the diagram showing the reference vectors registered in the reference memory (12a) at the same time, 1. For example, as shown in FIG. If it is small over the entire frequency range, the total value G
becomes approximately zero, and the properties of the motor (1) are determined to be good. Moreover, as shown in the same figure (b).

If the standard deviation vector E shown by the solid line becomes larger in some frequency bands than the reference vector F shown by the broken line, the total value G becomes larger corresponding to the area of the shaded part, and this causes the motor The properties of (1) are determined to be poor.

In addition, in this Fig. 4, the reference vector E is applied over all frequencies.
The size of the reference vector is kept constant, but the standard deviation allowed for each frequency component for removal is normally different, so the size of the reference vector can be changed depending on the frequency base depending on the control target. Just do it. In addition, in the above embodiment, the change amount calculation unit for calculating the amount of time change of one frequency component within a certain period of time is used as a frequency separation V? of the standard deviation vector. -1 Standard memo using a calculator that calculates the difference between the maximum and minimum values within a certain period of time!
J (12a) [() By setting the difference value and the value to be compared, it is possible to perform the same pass/fail judgment as described above.

Next, FIG. 5 is a block diagram showing a configuration according to the second invention, in which the same reference numerals as in FIGS. 1 and 3 indicate the same elements.

The difference from FIG. 1 and FIG. 6 is that two deviation accumulation systems are provided between the frequency analyzer and the determiner in the quality determining section (4). Among these, one system has the same configuration as shown in Fig. 6 above, and the other system basically has the same configuration as shown in Fig. 1, although an average value calculator (80) is added. .

Here, the average value calculator (80) is a frequency analyzer (io)
Based on the frequency spectrum of , the average value within a certain period of time is determined by dividing the frequency base, and the standard memo! J (12b) is set to the average value of the frequency components of the long-lasting device within a certain period of time.

Thereafter, in the same manner, both deviations are calculated by the difference device (1lb), and the deviation amount C is obtained by the accumulator (14b) K from the deviation obtained via the absolute value circuit α3).

Therefore, a deviation amount C, which is a comparison of the average value of frequency components within a certain period of time for each long-lasting device, and a summation value G, which is a comparison of standard deviations, are added to the judgment device (to), and these two are used together. pass/fail judgment.

By adopting such a configuration, it is possible to detect both continuous changes and instantaneous changes in the frequency spectrum due to equipment abnormalities, making comprehensive inspection possible.

In each of the first and second embodiments of the present invention, a well-known frequency analyzer with a wide frequency range is used, but if the frequency spectrum is known based on past experience and knowledge, By using a plurality of bandpass filters for one representative frequency component and rectifiers that rectify the outputs of these filters, a simple inspection device can be obtained.

Furthermore, in each of the first and second embodiments of the present invention described above, a case has been described in which the quality of the motor is determined by detecting noise, but if a vibration detector is used instead of a microphone,
It is also possible to determine the quality of equipment based on vibration, and furthermore, the inspection target is not limited to motors, and it goes without saying that the tuning fork can be applied to any equipment that generates vibrations during operation.

As described above, according to the first aspect of the present invention, the amount of change over time in the frequency substratum of the frequency spectrum to be inspected is obtained and compared with the reference value, so that the frequency spectrum is instantaneous or short. Even in the case of intermittent defective components that change only over time, product defects can be reliably detected. By performing these calculations together, it is possible to easily detect equipment abnormalities in which one frequency spectrum changes gradually and sharply, that is, continuous defective components, and it is also possible to make comprehensive pass/fail judgments. Effects can be obtained.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of a conventional sound or vibration testing device for equipment, Figure 2 is a diagram showing the relationship between sound frequency and component intensity to explain its operation, and Figure 6 is a diagram showing the relationship between sound frequency and component intensity. 4 is a block diagram showing the configuration of an embodiment of the apparatus for inspecting equipment using sound or vibration according to the first invention, and FIG. FIG. 5 is a block diagram showing the configuration of an embodiment of an apparatus for inspecting equipment using vibration for a tuning fork according to the second invention. (1): Motor (2) Two microphones (8
) Double-layer width analyzer (4): Pass/fail judgment unit (5): Display (10): Frequency analyzer (1 sword, (11
a), (11b): Differentiator aa s (12a), (1
2b): Reference memory (1B): Absolute value circuit (141, (14a) I (14b): Accumulator (151)
: Judgment device 06) Two control circuits: Standard deviation calculator 1211 : Non-negative circuit t801 : Average value calculator Shin Kuzuno - Procedural amendment (spontaneous) 21 Name of invention Inspection device for equipment by sound or vibration 3, Relationship with the person making the amendment Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Representative Hitoshi Katayama 4, Agent address Marunouchi, Chiyoda-ku, Tokyo 2-2-3, Mitsubishi Electric Corporation, 5, detailed description of the invention column of the specification subject to amendment, and drawings. 6. Contents of amendment (1) “Compare standard values” on page 14, line 11 of the specification
The statement "compared with the standard value" will be corrected. (2) Correct the drawing Medium Temperature 5 as shown in the attached sheet. 7. Inventory drawing of attached documents 1. Tools 1

Claims (6)

[Claims] (1) A detector that detects the sound or vibration of the object to be inspected and outputs an electrical signal, a frequency analyzer that obtains the frequency spectrum of this electrical signal, and a frequency component that measures the amount of time change in this frequency spectrum within a certain period of time. a change amount calculator for setting a value corresponding to the change amount of a long-term tester of the same type as the object to be inspected; a set value of the change amount setter and the change amount calculation unit; a deviation calculator for calculating a deviation for each frequency component by comparing the output of the device on the frequency component side, and an accumulator for calculating the cumulative value of the deviation for each frequency component,
A device for inspecting equipment using sound or vibration, characterized in that the quality of the object to be inspected is judged based on the output of the accumulator. (2) The apparatus for inspecting equipment using sound or vibration according to claim 1, wherein the change amount calculating unit calculates the standard deviation of the frequency component as the time change amount. (3) The change amount calculator calculates a difference value between the maximum value and the minimum value of the frequency component as the time change amount. ! F. An equipment inspection device using sound or vibration according to claim 1. (4) Claims 1 to 3, characterized in that the frequency analyzer is composed of a plurality of bandpass filters and a plurality of rectifiers that rectify the respective outputs of these bandpass filters. A device for inspecting equipment using sound or vibration as described in any of the above. (5) A detector that detects all sounds or vibrations of the object to be inspected and outputs an electrical signal, a frequency analyzer that obtains the frequency spectrum of this electrical signal, and the amount of time change in the frequency components of this frequency spectrum within a certain period of time. a change amount calculator that calculates the change amount on the frequency component side; a change amount setting device that sets a value corresponding to the change amount of the same type of long-lived equipment as the object to be inspected; a deviation calculator that compares the output of the change amount calculator to the frequency component side and calculates the deviation for each frequency component; and a first device that calculates the cumulative value of the deviation for each frequency component.
an accumulator, an average value calculator for calculating the average value of the frequency spectrum within a certain period of time for each frequency fraction, and an average value for setting a value corresponding to the average value of the long-lasting equipment of the same type as the object to be inspected. a value setter; an absolute value calculator for calculating the absolute value of the frequency-divided deviation by comparing the outputs of the average value setter and the average value calculator; and an absolute value calculator for calculating the cumulative value of the absolute value of the frequency-divided deviation. a second accumulator;
and a device testing device using sound or vibration, which is characterized by determining the quality of the object to be tested based on the output signal of the second accumulator. (6) The apparatus for inspecting equipment using sound or vibration according to claim 5, wherein the change amount calculator calculates the standard deviation of the frequency component as the time change amount. (γ) @The frequency analyzer is comprised of a plurality of bandpass filters and a plurality of rectifiers that rectify the respective outputs of these (D bandpass filters). Equipment inspection device using sound or vibration as described in item 6.