JPH10332475A - Diagnosis of deterioration of mechanical element of rotary body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve high degree stabilization of the operability and quality, adequate equipment maintenance and cost reduction, by arranging one sensor for many parts and thereby monitoring the deterioration of mechanical elements of a rotary body all the time without arranging one sensor for one part of the mechanical element. SOLUTION: A cable-shaped vibration detector 2, wherein a piezoelectric element is sealed, is brought close to parts to be diagnosed of a plurality of mechanical elements 1a of the rotary bodies, whose deterioration is to be diagnosed. The vibrating amount of the mechanical element 1a of the rotary body is determined and compared with the specified threshold value. Thus, the abnormal part at the part to be diagnosed, on which the vibration detector 2 is made to crawl, is judged as the area. Thus, the replacing time of the rotary mechanical part 1a having the above described abnormal part is judged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing deterioration of a rotating machine element, for example, a method of diagnosing a deterioration state of a rotating machine element such as a plurality of pumps and a transfer roll-shaped rotating body of the same kind. Things.

[0002]

2. Description of the Related Art To maintain a stable production state in equipment equipped with rotating body mechanical elements such as rotating body bearings and gears, it is necessary to constantly monitor the rotating body mechanical elements for abnormalities. Requires that measures be taken promptly. Conventionally, in response to such a demand, one vibration sensor is attached to one part of the rotating body mechanical element, and an AE (acoust
(JP-A-53-43588) for determining abnormality of a rotating machine element by detecting ic-emission)
Also, there is known an invention in which one sensor (a sensor for performing acceleration detection and AE detection) is attached to one part of a rotating body mechanical element to determine whether the rotating body mechanical element is abnormal (Japanese Patent Laid-Open No. 3-148035). ing.

[0003]

However, in the prior art described in Japanese Patent Application Laid-Open Nos. 53-43588 and 3-148035, one sensor is provided for one portion of the rotating machine element. Was needed. Therefore, when the above-mentioned conventional technology is applied to a case where a plurality of rotating body machine elements are present, the installation work of the sensor has to be performed on all of the plurality of rotating body machine elements. Furthermore, a system such as a charge amplifier and a data collection device necessary for each sensor is required, and a huge cost is required.

In view of the above, the present invention has been proposed in view of the above-mentioned problems of the prior art, and when performing deterioration diagnosis of a plurality of rotating body mechanical elements, each of the rotating body mechanical elements is individually provided. An object of the present invention is to easily perform deterioration diagnosis by arranging one sensor in multiple parts of a rotating body mechanical element instead of arranging one sensor.

[0005]

[Means for Solving the Problems]

(Features) The present invention is intended to achieve the above-mentioned object, and has the following features. According to the first aspect of the present invention, a cable-shaped vibration detecting device in which a piezoelectric element is sealed faces a diagnosis site of a plurality of rotating body mechanical elements whose deterioration is to be diagnosed, and a vibration amount of the plurality of rotating body mechanical elements is measured. By quantifying and comparing with a predetermined threshold value, an abnormal part in a diagnostic part facing the vibration detecting device is determined in an area, and a replacement time of a rotating machine element having the abnormal part is determined. It is characterized by the following.

[0006] The second aspect of the present invention is the first aspect of the present invention.
In addition to the features of the invention described above, noise from the vibration detection device is removed by an AR filter or an information filter that transmits only a signal that is a natural number multiple of the fundamental frequency of vibration. The AR filter mentioned above is Auto-r
This refers to an egressive (autoregressive) filter and is composed of a computer, circuit board, and the like. The above-mentioned information filter is a filter that passes only time-series signal data and frequency components necessary for diagnosis in advance and cuts other signals, and is composed of a computer, a circuit board, and the like.

(Operation) The operation of the present invention having the above configuration will be described below. When an abnormality such as, for example, a bearing flaw occurs in the rotating body mechanical element, a collision starting from the flaw occurs, and vibration occurs. Also, when vibration is transmitted to the piezoelectric element itself, as in an acceleration sensor, an electric charge is generated in proportion to the acceleration of the vibration.

According to the first aspect of the present invention, a cable-shaped vibration detecting device enclosing a piezoelectric element having the above-described characteristics is provided along a diagnosis site of a plurality of rotating body mechanical elements whose deterioration is to be diagnosed. In addition, abnormalities occurring in any of the diagnostic sites covered by the vibration detection device can be determined in terms of area. Also, in a cable-shaped vibration detecting device in which a piezoelectric element is sealed, the entire cable picks up noise other than various equipment signals as a sensor.

According to the second aspect of the present invention, as means for improving the S / N ratio, by removing noise using an AR filter or an information filter, it is possible to clearly extract abnormalities of the rotating body mechanical elements.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (Examination of the effectiveness of deterioration diagnosis using a cable enclosing a piezoelectric element) The present inventor compared the vibration characteristics of a piezoelectric cable encapsulating a piezoelectric element with a conventional acceleration vibration sensor, and conducted a survey from the viewpoint of abnormality detection. Study was carried out. The results of this study are shown in FIGS.

FIG. 1 is an explanatory view showing a coherence comparison between a piezoelectric cable in which a piezoelectric element used in the present invention is enclosed and a conventional acceleration vibration sensor. FIG. 2 is a diagram in which a piezoelectric element used in the present invention is enclosed. FIG. 3 is an explanatory diagram showing abnormality detection comparison in frequency analysis between a piezoelectric cable and a conventional acceleration vibration sensor, and FIG. 3 is an explanatory diagram showing noise processing by an AR filter.

First, a coherence comparison between a conventional acceleration vibration sensor and a piezoelectric cable enclosing a piezoelectric element used in the present invention will be described with reference to FIG. The graph shown in FIG. 1 shows the coherent function value on the vertical axis and the frequency (kHz) on the horizontal axis. As shown in FIG. 1, the coherence of the piezoelectric cable in which the piezoelectric element is sealed is only 1 kHz as compared with the conventional acceleration vibration sensor.

Next, with reference to FIG. 2, a study will be made as to whether or not a Brg outer ring flaw can be detected by a piezoelectric cable in which the above-described piezoelectric element is sealed. In the graph shown in FIG. 2, the vertical axis represents the power spectrum, and the horizontal axis represents the frequency (kHz).
The lower row shows values of a conventional acceleration sensor, and the upper row shows values of a piezoelectric cable in which a piezoelectric element used in the present invention is sealed. As shown in FIG. 2, the result of the frequency analysis confirmed that although the SN ratio of the piezoelectric cable in which the piezoelectric element was encapsulated was lower than that of the comparative sensor, it was possible to catch the abnormality of the bearing.

Next, a description will be given of how noise is removed by using an AR filter with reference to FIG.
In addition, the graph shown in FIG.
Frequency (kHz) is plotted on the horizontal axis.
Before passing through the filter, the lower part shows the value after passing through the AR filter. As shown in FIG. 3, even with a piezoelectric cable having a cable length of 5 m, there is no dependency on the vibration detection position, so that area diagnosis using the piezoelectric cable is possible. Furthermore, it was confirmed that even with a cable-like piezoelectric element having a characteristic of easily picking up power supply noise and the like, an abnormal signal can be clearly extracted by using an AR filter.

(General Embodiment of the Present Invention) In the method for diagnosing deterioration of a rotating body mechanical element according to the present invention, when a rotating body reaches an operating state at a certain rotational speed, vibration data obtained from a vibration detecting device is obtained. And separately measured rotation speed data are stored as normal data. Then, after noise is removed from the signal data output from the vibration detection device by an AR filter, frequency analysis and time series analysis are performed, and trend management is always performed as a diagnostic parameter.

Here, when an abnormality is detected, it can be determined that an abnormality has occurred in any of the plurality of parts covered by the vibration detecting device, and the abnormal part is specified. That is, when an abnormality is detected, a detailed diagnosis is performed for each part in the vibration detection device, and an abnormality countermeasure such as replacement of the abnormal part is performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a case where the present invention is applied to a steel sheet conveying process will be described. FIG. 4 is a block diagram illustrating an arrangement of a table roll as a rotating body to which the deterioration diagnosis method according to the present invention is applied, and an attached state of a piezoelectric cable as a vibration detecting device.

As shown in FIG. 4, each of the plurality of table rolls 1 has a pair of bearings 1a and a gear 1b meshing with the bearings 1a. A piezoelectric cable 2 as a vibration detecting device faces along each bearing 1a of the plurality of table rolls 1. Although not shown in detail, the piezoelectric cable 2 has a piezoelectric element sealed in the cable. Also, the piezoelectric cable 2 has
A data collection device 4 is connected via an AR filter 3. Further, an arithmetic circuit 5 is connected to the data collection device 4. The arithmetic circuit 5 includes a speaker and a CR.
An alarm 6 composed of a T display device or the like is connected. Note that an information filter may be used instead of the AR filter 3 to remove noise.

In order to determine the deterioration of mechanical elements such as the bearings 1a and gears 1b provided in the table roll 1 as a rotating body, the rotation number of the table roll 1 and the table roll 1 Bearing 1a
The AR filter 3 is created by measuring the vibration value of. Then, the bearing vibration data at the time when the predetermined number of rotations is reached is represented by A
After noise is removed by the R filter 3, the data is input to the data collection device 4 to collect data. The data collected by the data collection device 4 is subjected to time-series analysis and frequency analysis by the arithmetic circuit 5 to be converted into feature parameters. Then, the characteristic parameters are trend-managed, and an alarm is generated by the alarm device 6 when an abnormality is detected. When an abnormality is confirmed by an alarm, a countermeasure against the abnormality is taken, for example, by replacing a mechanical element such as the bearing 1a or the gear 1b at the site where the abnormality has occurred.

[0020]

Since the present invention has the above-described structure,
The following effects can be obtained. According to the first aspect of the present invention, since one sensor is not required for each part of a plurality of mechanical elements, deterioration diagnosis can be performed easily and cost can be reduced. Specifically, in the process of transporting a steel sheet, which previously required one sensor for one part of a mechanical element, the number of sensors to be mounted is reduced to about 1/15, and significant cost reduction can be achieved. . According to the second aspect of the present invention, by improving the S / N ratio of the data signal using an AR filter or the like, it is possible to clearly extract an abnormality of the rotating body mechanical element.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a coherence comparison between a piezoelectric cable enclosing a piezoelectric element used in the present invention and a conventional acceleration vibration sensor.

FIG. 2 is an explanatory diagram showing an abnormality detection comparison in frequency analysis between a piezoelectric cable enclosing a piezoelectric element used in the present invention and a conventional acceleration vibration sensor.

FIG. 3 is an explanatory diagram showing noise processing by an AR filter.

FIG. 4 is a block diagram illustrating an arrangement of table rolls to which the present invention is applied and a mounting state of a piezoelectric cable.

[Description of Signs] 1 Table roll 1a Bearing 1b Gear 2 Piezoelectric cable 3 AR filter 4 Data collection device 5 Arithmetic circuit 6 Alarm

Continuation of front page (72) Inventor Kenji Maekawa 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division

Claims (2)

[Claims] 1. A method of diagnosing deterioration of a plurality of rotating machine elements of the same type, comprising: diagnosing a plurality of rotating body machine elements whose deterioration is to be diagnosed by a cable-shaped vibration detecting device enclosing a piezoelectric element. Face the site, quantify the vibration amount of the plurality of rotating body mechanical elements, and by comparing with a predetermined threshold value, face the vibration detection device, determine the abnormal site in the diagnosis site in area, A method for diagnosing deterioration of a rotating machine element, comprising determining a replacement time of the rotating machine element having the abnormal portion. 2. The rotating body mechanical element according to claim 1, wherein noise from the vibration detecting device is removed by an AR filter or an information filter that transmits only a signal that is a natural number multiple of the fundamental frequency of the vibration. Deterioration diagnosis method.