JPS5997016A - Inspector for equipment with sound or vibration - Google Patents

Abstract

PURPOSE:To enable detection of deficiency of equipment which generates a deficiency sound only instantaneously by continuously determining an average within a fixed time of the frequency spectrum from an object to be inspected so as to compare a frequency spectrum with the current average spectrum. CONSTITUTION:A noise of a motor 1 is taken into a frequency analyzer 10 through a microphone 2 and an amplifier 3 and a frequency spectrum A corresponding to the noise is determined continuously to be applied to a differential device 11 and an averager 20 with which an average within a fixed time in terms of frequencies is determined based on the spectrum A and the average spectrum B is applied to the differential device 11 as comparison input. The spectrums A and B are compared with an arithmetic mechanism to determine a deviation value. In other words, after a comparison with the differential device 11, deviation value are totalized with a totalizer 14 through an absolute value circuit 13 and the total sum G applied to a discriminator 15. The discriminator 15 compares the total sum G with the set value and judges the object to be good when the total sum G is below the set value while to be defective when it exceeds the specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for inspecting equipment using sound or vibration, which detects vibrations generated by a tuning fork during operation of the 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) The total noise of 1) is converted into an electrical signal by the microphone (2), this electrical signal is amplified by the amplifier (8) and sent to the pass/fail judgment section (4), and the judgment result is displayed on the display (5). It is.

Here, the pass/fail determining section (4) includes a frequency analyzer α0) 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 an input of this frequency spectrum A'). On the other hand, the motor (
Reference memo IJ in which the frequency spectrum (or design data) of a motor of the same type as 1) and with good properties is registered in advance (Input the reference spectrum B of 121 and compare them to find the frequency analyzer difference. (11), an absolute value circuit (181) that inputs the difference number of this difference device σ sword and calculates its absolute value (181), and an absolute value circuit (181) that accumulates these absolute deviations to sum up all frequencies (hereinafter referred to as deviation amount) C. an accumulator α4 that calculates the deviation amount C, a determiner (b) that determines whether the deviation amount C exceeds a preset value or not, and a control circuit (16) that operates these components in association with each other.
It is equipped with.

When the electric signal corresponding to the noise of the motor (1) is added to the total quality determination section (4), the frequency spectrum A and the reference spectrum B are compared, and the difference in the distribution including the level is determined as the deviation ic. When the deviation amount C is less than or equal to the set value, it is determined that the motor (1) is in good condition, and when this deviation itc exceeds the set value, the motor (1) is determined to be in good condition.
) is determined to be defective.

Furthermore, what is the frequency spectrum of a motor with good properties that is registered in the memory as the reference spectrum B?

The frequency spectrum of the motor with the best performance,
Alternatively, it refers to the average value of the frequency spectrum of a large number of motors that are considered to be good products, and even if these deviations are adopted, similar pass/fail judgments can be made by appropriately determining the pass/fail judgment level set in the judge (to). It is done.

Figures 2 (a) and (1)) are diagrams that simultaneously show the frequency spectrum of the motor (1) determined by the frequency analyzer and the reference spectrum registered in the reference memo. When the frequency spectrum A shown by the r/c1 solid line and the reference spectrum B shown by the broken line are similar as in (a), the value of the deviation amount C corresponding to the deviation of the biconvex line, that is, the area of the diagonal line becomes smaller, which makes the motor (
The properties of 1) are determined to be good.

In addition, as shown in Figure (b), if there is a partially large intensity difference between the frequency spectrum A shown in the actual recording and the reference spectrum B shown by the broken line, the area of the fe+ line part The value of the deviation amount C 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 deviations for each frequency range, or If the deviations in the portions where the frequency spectrum A is smaller than the reference spectrum B are removed and only the deviations in the portions where the frequency spectrum A is larger than the reference spectrum B are accumulated, 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 the entire 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 its magnitude. Highly accurate pass/fail judgment is possible by determining the average deviation amount within a unit time. 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 % reference spectrum includes the deviation as it can be seen as a change over time. For example, a bearing may become defective for a short period of time due to foreign matter getting into it.
Even if the defective frequency component associated with this momentarily increases, averaging operation will reduce the instantaneous abnormal component and only slightly increase the amount of deviation, so this can be interpreted as a change over time. This has the drawback of not being able to detect defects as a result.

The present invention has been made to eliminate the drawbacks of the conventional ones described above, and the tuning fork to be inspected continuously calculates the average value of the vibration frequency spectrum within a certain period of time, and converts the frequency spectrum into the average spectrum at that point. It is an object of the present invention to provide a sound or vibration testing device for equipment that can reliably detect equipment failures that only momentarily generate faulty sounds based on the comparison results.

The present invention will be described below with reference to the accompanying drawings. First, FIG. 3 shows +I caused by sound or vibration according to the first invention.
1 is a block diagram showing the configuration of an I-device inspection device, in which the same reference numerals as in FIG. 1 indicate the same elements, respectively. Between the 1 frequency analyzer α0) and the differentiator 01,
It differs from Figure 1 in that it adds an averager that continuously calculates the time average of the frequency components of the frequency spectrum for each frequency over a certain period of time, and eliminates the reference memory (2) in Figure 1. The average spectrum B obtained by the averager ■ is used as a comparison input for the frequency spectrum A obtained by the frequency analyzer, which is input to the subtractor (by outputting it in one line), and is calculated by the calculation mechanism below the subtractor Qη. The frequency spectrum A is compared with the average spectrum B at that time to determine the amount of deviation, and the quality of the inspected object is determined based on the amount of deviation.

The operation of the apparatus for inspecting equipment using sound or vibration according to the present invention configured as described above will be explained below. First, the motor (1
) during rotation is the same as the conventional model.

It is converted into an electrical signal by the microphone (2).

This is taken into the frequency analyzer αQ via the amplifier (8) and frequency-analyzed, and the frequency spectrum A corresponding to the noise of the motor (1) is obtained from time to time. added to. Therefore, in the averager (2), a time average within a certain period of time is continuously obtained for each frequency based on the frequency spectrum A, and the average spectrum B is added as a comparison input to the above-mentioned difference device σ. .

Here, the period for obtaining the average is determined in accordance with the time variation of the frequency spectrum A to be tested, and the average spectrum B to be found is made to approximately follow changes in the sound to be tested.

Then, the frequency spectra A obtained one after another and the average spectrum B at that point in time are compared by a calculation mechanism to determine the amount of deviation. Namely.

The deviation amount is compared by the difference device α, and the deviation amount is accumulated by the accumulator α4 via the absolute value circuit αB), and the sum value G is added to the determiner (b). As described above, the determiner Cl5) compares this total value G with the set value set here, and when the total value G is less than the set value, the motor ( It is determined that the properties of motor (1) are good"U6, and when the sum value G exceeds the set value, it is determined that the properties of motor (1) are bad. Therefore, a defective sound in which the frequency spectrum A changes in a short time When input, the amount of deviation at that point becomes large and detected, and can be easily identified as defective by the judgment device (LI).On the other hand, since slow time changes (average ■ pursues It can be determined correctly without being detected as a quantity.

Next, FIG. 4 is a block diagram showing a configuration according to the second invention, in which the same reference numerals as in FIGS. 1 and 6 indicate the same elements, respectively.

Therefore, the first point is that there are two deviation accumulation systems between the frequency analyzer of the pass/fail judge (4) circle and the judge μs.
It is different from Fig. 6 and Fig. 6. Among these, one system has the same configuration as shown in Fig. 3 above, and the other system is a calculation mechanism that calculates the deviation by comparing the average spectrum obtained by the averager ■ with the reference spectrum set by the reference value setting device. This is a configuration that adds .

In other words, in the configuration shown in FIG. 1, the frequency spectrum A is compared with the average spectrum B at that point in time, and the deviation amount Gi is determined by the judger 115), which is the same as in FIG. 3, but in addition to this, the standard Reference memory that serves as a value setter (
1@ is set as a frequency analyzer for measuring the frequency components of long-term equipment within a certain period of time, and in the same way, a difference device (1lb) calculates the deviation between the average spectrum B and the reference spectrum C, and an absolute value circuit (13b) ) is added to calculate the deviation amount C using an accumulator (14b). Therefore, the determiner (to) calculates the reference spectrum C and the average spectrum B' (i-comparison/hi deviation amount H) of the frequency components within a certain period of time for the long-duration equipment, respectively.

The deviation amount G obtained by comparing the frequency spectrum A with the average spectrum B at that time is added, and both are used in combination to determine the quality.

According to such a configuration, a function that compares the average of the one-round mantissa spectrum with a reference is also used, so it is possible to detect not only truncated sounds whose frequency spectrum changes in a short period of time, but also unnecessary sounds that occur continuously. can also be detected, making comprehensive inspection possible.

By adopting such a configuration, +! It is possible to detect both continuous and instantaneous changes in the frequency spectrum associated with an abnormality in a single device, 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 as the frequency analyzer αO), but the frequency spectrum is known based on past experience and knowledge. In some cases, an inspection device with a simple configuration can be obtained by using a plurality of bandpass filters for representative frequency components and rectifiers that rectify their outputs.

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 it goes without saying that the inspection target is not limited to motors, but can be applied to all equipment that generates sound or vibration during operation.

As described above, according to the first aspect of the present invention, the average of each frequency fraction within a certain period of time of the target frequency spectrum is continuously calculated and the frequency spectrum to be judged is compared with the average at that time. Therefore, even if the frequency spectrum changes slowly and greatly over time, intermittent defective components can be reliably detected and pass/fail judgments can be made with high reliability. Furthermore, according to the second aspect of the present invention, by also calculating the deviation between the average value of each frequency fraction within a certain period of time and the reference value, nine instruments of the type in which the frequency spectrum changes slowly and greatly can be obtained. An excellent effect is obtained in that abnormalities, that is, continuous defective components can be easily detected, and comprehensive quality judgment can be made.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of a conventional tuning fork or vibration-based equipment inspection device, Fig. 2 is a diagram showing the relationship between sound frequency and component intensity to explain its full effect, and Fig. 6 is a diagram showing the relationship between sound frequency and component intensity. 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. 4 is a block diagram showing an embodiment of the apparatus for inspecting equipment using sound or vibration according to the second invention. FIG. 2 is a block diagram showing the configuration. (1): Motor (2) Two microphones (8
): Amplifier (4): Pass/Fail Judgment Unit (5): Display αQ: Frequency Analyzer (11), (11
a) s (11b) ': Differentiator (2): Reference memory (11) S (1 pot) s (13fi): Absolute value circuit ('4f + (14a) + (14b): Accumulator -)
2. Judgment device α6) 2. Control circuit ■: Averager agent Ina Kuzuno - Procedural amendment (voluntary) Showa 5 Hayabusa April 148 2. Name of the invention Device for testing equipment using sound or vibration 3. Representative of the person making the amendment Hitoshi Katayama, Department 4, Agent 5, detailed description of the invention in the specification subject to amendment, and drawings. 6. Contents of the amendment (1) The statement "In other words, in the configuration shown in the drawings... pass/fail judgment is made" from page 10, line 19 to page 11, line 14 of the specification has been amended as follows. do. ``In other words, in the illustrated configuration, the frequency spectrum A is compared with the average spectrum B at that point in time, the deviation amount G is obtained, and the quality is judged by the judge (15), which is the same as in Fig. 3. In addition, the frequency spectrum (or design data) of the long-lasting device is set as the reference spectrum B' in the reference memory (12), which serves as a reference value setting device, and the average spectrum B and the reference spectrum are similarly calculated using the difference unit (llb). The deviation from B' is calculated and the absolute value circuit (13b
), an arithmetic mechanism is added for calculating the deviation amount H using an accumulator (14b) from the deviation obtained through the above steps. Therefore, the -determiner (15) receives the deviation amount H obtained by comparing the reference spectrum B' and the average spectrum B, and the deviation amount G obtained by comparing the frequency spectrum A with the average spectrum B at that time. Both are used together to determine pass/fail. ” (2) From page 11, line 20 to page 12, line 3 of the specification, “
With such a configuration... comprehensive inspection becomes possible. ” will be deleted. (3) Correct the drawing Medium Temperature 4 as shown in the attached sheet. 7. Inventory drawing of attached documents 1. Tools 1

Claims (1)

[Claims] (1) The tuning fork to be inspected includes a detector that detects all vibrations and outputs an electrical signal, a frequency analyzer that obtains the frequency spectrum of this electrical signal, and a frequency analyzer that detects the frequency spectrum of this electrical signal within a certain time. It is fully equipped with an averager that continuously calculates a time average for each frequency, and an arithmetic mechanism that compares the frequency spectrum with the average spectrum obtained by the averager at that time and calculates a deviation amount, and based on the deviation amount, An equipment inspection device that uses sound or vibration to determine the quality of an object to be inspected. (2) The frequency analyzer includes a plurality of bandpass filters and a plurality of rectifiers that rectify the outputs of the respective bandpass filters. Equipment inspection device using vibration. (8) A detector that detects the sound or vibration of the object to be inspected and outputs an electrical signal, a frequency analyzer that can obtain the frequency spectrum of this electrical signal, and a continuous average of this frequency spectrum within a certain period of time for each frequency. A first step in which the deviation amount is determined by comparing the frequency spectrum with the average spectrum determined by the averager at that time.
a calculation mechanism, a reference value setting device for setting a reference spectrum of a device with good characteristics of the same type as the object to be inspected, and a second device for calculating a deviation amount by comparing the reference spectrum and the average spectrum. What is claimed is: 1. An apparatus for inspecting equipment using sound or vibration, comprising: a calculating mechanism, and determining the quality of the object to be inspected based on the amount of deviation between the two calculated by the first and second calculating mechanisms. (4) The tuning fork according to claim 6, wherein the frequency analyzer includes a plurality of bandpass filters and a plurality of rectifiers that rectify the outputs of the respective bandpass filters. Equipment inspection device using vibration.