JPH0663827B2 - How to determine if there is a vibration disorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to a vibration obstacle for determining whether or not a vibration obstacle generated in a factory and propagated to a surrounding site causes a vibration obstacle in a nearby residential area or the like. It relates to a method of determining the presence or absence.

[Conventional technology]

Conventionally, in a factory having a vibration source such as a compressor, a mill, and a fan, an electric measuring instrument such as an ammeter is directly connected to each vibration source, and the current status is monitored to determine whether or not there is any abnormality in the vibration source.

[Problems to be Solved by the Invention]

In order to prevent the vibration generated at the factory from propagating to the surrounding premises and causing an obstacle in the vicinity, it is necessary to judge whether or not there is a vibration obstacle at the boundary of the factory premises, but in the past this viewpoint is lacking. However, there was only a symptomatic treatment that the processing such as the output reduction of the vibration source was performed only when there was a complaint from the neighborhood.

However, in a factory location where houses are lined up near the factory site, it is absolutely necessary to determine the presence or absence of a vibration obstacle at the boundary of the factory site in order to quickly detect the vibration source and take appropriate measures.

[Object of the Invention]

The present invention has been made to solve the above problems, and provides a method capable of reliably determining the presence or absence of a vibration obstacle without being affected by disturbance (traffic vibration, construction vibration, etc.) at the boundary of a factory site. The purpose is to do.

[Means for Solving the Problems]

A first invention is to install a vibration measuring sensor at the boundary of a factory site having a vibration source, and also to install one vibration measuring sensor near the vibration source on the factory site, and at the same time, perform a vibration measurement and use a computer. To calculate the power spectrum by converting the measurement data near the vibration source (time axis data) into the frequency data, and obtain the cross spectrum using the measurement data at the site boundary and the measurement data near the vibration measurement. When the power spectrum and the outstanding peak frequency of the cross spectrum coincide with each other, it is judged whether or not the peak vibration value of the cross spectrum is a level at which a vibration failure occurs.

A second aspect of the invention is to install a plurality of vibration measuring sensors on the boundary of the site of a factory having a vibration source, simultaneously measure the vibration, and convert the measurement data (time axis data) into frequency data by a computer. It is characterized in that the power spectrum at each measurement point on the boundary is obtained, these power spectra are summed, and it is judged whether or not the level is a level at which vibration disturbance occurs with respect to the peak amplitude value.

〔Example〕

First, a spectrum measuring apparatus used for carrying out the present invention will be described with reference to FIGS. 1 and 2.

In the figure, 1 is a vibration measuring sensor (displacement meter, speedometer or accelerometer), which is installed near the vibration source in the factory site 3 apart from the site boundary 2 and connected to the control center 4.

Reference numerals 5 ₁ , 5 ₂ , ..., 5 _{n denote} a plurality of vibration measuring sensors, which are installed at the site boundary 2 and connected to the control center 4.

In the control center 4, there is a computer 6, the sensors ₁ , 5 ₁ , 5 ₂ , ..., 5 _n and an amplifier 7,
8 _{1, 8} 2, ..., are connected via a _{8 n,} and A-D converter 9 controlled by the computer 6 is provided. The computer 6 is input and set with an integration formula of a correlation function and a cross-correlation function, a Fourier transform formula, and a judgment formula of vibration disturbance as specification values.

The first method of the present invention using the above-mentioned spectrum measuring apparatus is
Description will be given with reference to FIGS.

The vibration generated from the factory is separated from the site boundary 2 by the sensor 1 installed near the vibration source in the factory site 3 and the sensors 5 ₁ , 5 ₂ , ..., 5 _n installed at the site boundary 2. And the measurement signal is output to the control center 4. Then, in the control center 4, the sensor 1,
The measured data (time axis data, here, measured waveform) input from 5 ₁ , 5 ₂ , ..., 5 _n are amplifiers 7, 8 ₁ , 8
_2, ... are amplified by 8 _n, after being digitized by A-D converter 9, the presence judgment described below such spectrum analysis and vibration failure by the computer 6 is performed.

(1) Spectral analysis method Measurement point (sensor installation position) on site boundary 2 and site boundary 2
If the measurement points (sensor installation positions) near the vibration source in the factory premises 3 away from the measurement points are the measurement points P and Q, respectively, as shown in FIG. 3, the measurement data at the fixed points P and Q on both sides will vibrate. A Fourier spectrum corresponding to the measured waveform is obtained by converting the data into several axis data. This Fourier spectrum shows the magnitude of the amplitude with respect to the frequency. 4 (A) and (B) are the measurement data (measurement waveform) at the measurement point P.
And the Fourier spectrum are shown.

Further, an autocorrelation function is calculated for the measurement data at each measurement point P, Q and converted into frequency axis data to obtain a power spectrum corresponding to each autocorrelation function.
This power spectrum shows its power value against frequency. 5A and 5B show the autocorrelation function and the power spectrum based on the measurement data at the measurement point P.

Further, a cross-correlation function is calculated for the measurement data at the two measurement points P and Q and converted into frequency axis data to obtain a cross spectrum corresponding to the cross-correlation function. This cross spectrum shows the magnitude of the correlation function at each frequency between the two measured data. FIGS. 6 (A) and 6 (B) show the cross-correlation function and cross spectrum between the measurement data at the two measurement points P and Q.

For example, if the measurement data at the measurement point P has an excellent frequency component, but the measurement data at the measurement point Q does not include the frequency component, or if it does not include that frequency component, the crossing between the two measurement points P and Q Its amplitude value in the spectrum is small. More specifically, FIG. 4 (A) obtained at the measurement point P.
Even in the measurement waveform shown in Fig. 4, the Fourier waveform shown in Fig.
From the spectrum and the power spectrum shown in FIG. 5 (B), the frequency component around 9 Hz is dominant,
In the measurement data at the measurement point Q, since the frequency component is small, the amplitude value becomes small in the cross spectrum at the two measurement points P and Q shown in FIG. 6 (B). Rather, FIG. 6 (B) shows that the correlation between the two measurement data is strong near 5 Hz. From this,
The factory produces vibrations with a frequency of about 5 Hz, and it is clear from measurements at site boundary 2 that the frequency components around 9 Hz were outstanding due to the effects of disturbance (traffic vibration, construction vibration, etc.).

(2) Judgment method for presence / absence of vibration disturbance (1) This method is used when the outstanding peak frequencies of the power spectrum at the measurement point Q and the cross spectrum at the two measurement points P and Q match. It is to judge whether or not the peak amplitude value of the cross spectrum is a level at which a vibration failure occurs.

The above-mentioned example in which the measurement results shown in FIGS. 4 to 6 are obtained is the case where the vibration source is the compressor, and the power spectrum at the measurement point Q and the cross spectrum at the two measurement points P and Q are shown. The outstanding peak frequencies match at around 5 Hz, in which case the cross spectrum peak amplitude value is 2.
When 5 is smaller than the amplitude value of the vibration obstacle judgment level, it is judged that there is no vibration obstacle, and when it is larger, it is judged that there is vibration obstacle.

The example in which the measurement results shown in Fig. 7 are obtained is when the vibration source is a cooling fan, and the peak spectrum of the power spectrum at the measurement point Q and the cross spectrum at the two measurement points P and Q is excellent. The numbers match at around 5.5 Hz, and in such a case, when the peak vibration value 40 of the cross spectrum is smaller than the amplitude value of the vibration obstacle judgment level, it is judged that there is no vibration obstacle, and when it is large, it is judged that there is a vibration obstacle. . For example, if the amplitude value of the vibration failure determination level is set to 10, it is determined that there is a vibration failure.

The above two examples are the case where the vibration source exists in the factory site 3, but when the vibration source does not exist in the factory site 3, as shown in FIG. Although the outstanding peak frequency of the cross spectrum at the measurement points P and Q is found near 5 Hz instead of around 5.5 Hz, its amplitude value is small and the correlation function between the two measurement data is small. In such a case, since the peak vibration value of the cross spectrum is considerably smaller than the amplitude value of the vibration trouble determination level, it is judged that there is no vibration trouble.

The above-mentioned example in which the measurement results shown in FIG. 7 were obtained had a vibration failure in a private house around the factory, and this example will be described in more detail below.

In the industry, compressor equipment is constantly operating, and it was initially thought that this was a vibration source, but as a result of applying this method, the results shown in FIG. 7 were obtained, and the vibration source was a cooling fan, and , 5.5Hz was found to be the dominant frequency of the cooling fan.

The vibration measuring sensor C used is, as shown in FIG.
It was installed on the site boundary of the factory, on the factory site away from the site boundary, and in a residential area adjacent to the factory. The vibrations in the X, Y, and Z directions were measured during the operation of the cooling fan and when the cooling fan was stopped. 10 (A) and 10 (B) are X-direction cross spectrum amplitude distributions at each measurement point during cooling fan operation and when stopped, and FIGS. 11 (A) and 11 (B) are during cooling fan operation and when stopped. Y-direction cross spectrum amplitude distribution at each measurement point in FIG.
(B) shows the Z-direction cross spectrum amplitude distribution at each measurement point during the cooling fan operation and at the time of stop. From these measurement results, the vibration propagating from the cooling fan during operation vibrates in the X, Y, and Z directions, and particularly in the Z direction perpendicular to the ground, and as it gets closer to the vibration source, it vibrates strongly.
It was also found that the amplitude value drastically decreases when the cooling fan is stopped.

(3) Judgment method for presence / absence of vibration disturbance (No. 2) These power spectra are summed up and it is judged whether or not the peak vibration value is at a level at which vibration disturbance occurs.

In this method, the power spectra at each measurement point P are added together, and it is determined whether or not the peak amplitude value is at a level at which a vibration failure occurs.

This is based on the idea that even if the measurement at the site boundary 2 is affected by disturbance (traffic vibration, construction vibration, etc.), the same frequency component does not predominate at all measurement points P. ,
This is effective when the vibration source cannot be specified.

(4) Judgment result of presence / absence of vibration trouble When there is a vibration trouble, it becomes possible to control the output reduction of the vibration source and issue an alarm. In addition, if there is no vibration trouble, the current operating state may be maintained.

〔The invention's effect〕

The first effect of the present invention is to superimpose the cross spectrum by the sensor near the vibration source and the sensor installed at the site boundary with the power spectrum near the vibration source to obtain the peak of the power spectrum and the peak of the cross spectrum. Since the vibration of the vibration source is determined only at the vibration frequency at which the values coincide with each other, that is, only the vibration component having a high correlation with the vibration source, the vibration of the vibration source can be clearly captured. That is, the vibration component not included in the vibration source is removed. For example, when the entire site vibrates due to an earthquake or the like, the present invention is distinguished since it has nothing to do with the vibration of the vibration source.

Secondly, the sum of the power spectra is a spectrum in which vibration of the common component is large and other noise-like components are small. Therefore, even if different vibrations occur simultaneously at a plurality of points, the peak of the vector does not increase, and the vibration of the vibration source can be clearly captured regardless of the vibration of the vibration source to be detected.

Further, the vibration source and its dominant frequency can be specified in real time. Therefore, it is possible to set up a countermeasure against vibration surely and quickly, and it is useful for determining the position of the vibration source in the layout of the factory.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a spectrum measuring apparatus for carrying out the invention, FIG. 2 is a conceptual diagram of the method of the invention, FIG. 3 is a plan view showing measuring points P and Q, and FIG. Figures (A) and (B) show measurement point P
Graph showing measured waveform and Fourier spectrum at
5 (A) and 5 (B) are graphs showing the autocorrelation function and power spectrum at the measurement point P, and FIG. 6 (A) and
(B) is a graph showing a cross-correlation function and a cross spectrum at the measurement points P and Q, and FIGS. 7 (A) and 7 (B) are powers at the measurement point Q when a vibration source exists on the factory premises. The number of autocorrelations and the power at the measurement point P with the spectrum
Graphs showing spectra, FIGS. 6 (A) and (B) showing graphs of cross spectra at measurement points P and Q, and FIGS. 8 (A) and 8 (B) showing no vibration source within the factory premises. In the case of the power spectrum at the measurement point Q and the cross spectrum at the measurement points P and Q, FIG. 9 is a plan view showing the measurement points at the actual factory and its surroundings, FIG. 10 (A),
(B) is an X-direction cross spectrum amplitude distribution chart at each measurement point during cooling fan operation and when stopped, and FIGS. 11A and 11B show at each measurement point during cooling fan operation and during stop. Y-direction cross spectrum amplitude distribution chart, first
2 (A) and 2 (B) are Z-direction cross spectrum amplitude distribution diagrams at each measurement point during the operation of the cooling fan and when the cooling fan is stopped. ₁ , 5 ₁ , 5 ₂ , ..., 5 _n , C0, C1, ...
C11 ... Vibration measurement sensor, 2 ... Site boundary, 3 ...
… Factory site, 4… Control center, 6… Computer, 7, 8 ₁ , 8 ₂ , ..., 8 _n … Amplifier, 9 ……
A-D converter, P, Q ... Measuring point.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihisa Ishibashi 2-19-1 Tobita, Chofu-shi, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (56) References: 61-129135

Claims (2)

[Claims] 1. A vibration measuring sensor is installed on the boundary of a site of a factory having a vibration source, and 1 is installed near the vibration source on the factory site.
The vibration measurement sensor is installed at the same time, the vibration measurement is performed at the same time, the measurement data near the vibration source (time axis data) is converted into frequency data by the computer to obtain the power spectrum, and the measurement data at the site boundary is also measured. And the measured data near the vibration source are used to determine the cross spectrum, and if the power spectrum and the predominant peak frequency of the cross spectrum match, vibration disturbance will occur for the peak vibration value of the cross spectrum. A method for determining the presence or absence of a vibration disorder, which comprises determining whether or not the level is a level at which it occurs. 2. A plurality of vibration measuring sensors are installed at the boundary of a site of a factory having a vibration source, and the vibration is measured simultaneously.
The measured data (time axis data) is converted to frequency data by a computer to obtain the power spectrum at each measurement point on the site boundary, and these power spectra are added together,
A method for determining the presence or absence of a vibration disorder, which comprises determining whether or not the level is such that a vibration disorder occurs with respect to the peak amplitude value.