JP2010237033A - Device and method for failure diagnosis of rotary shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a failure diagnosis device for receiving an elastic wave generated in company with crack generation or development of a material, directly without attenuation, and to provide a failure diagnosis method using the failure diagnosis device. <P>SOLUTION: The failure diagnosis device includes an elastic wave detection means, and an failure diagnosis means for diagnosis of a failure based on a signal from the elastic wave detection means. The elastic wave detection means includes a liquid reservoir for collecting liquid in contact with part of a rotary shaft, and an acoustic emission (AE) sensor installed in contact with the liquid reservoir. The failure diagnosis means diagnoses a failure of the rotary shaft by using the failure diagnosis device having a function for diagnosis of a failure generated in the rotary shaft by analyzing the detected elastic wave. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a diagnostic device for diagnosing abnormalities such as cracks occurring in a rotating shaft and an abnormality diagnosing method using the diagnostic device. This is detected by a sensor (AE) and diagnoses whether or not an abnormality has occurred based on this detection signal.

For example, in an iron manufacturing plant equipped with a rolling mill and a conveyance line, a large number of gears and rotating shafts are provided for transmitting the driving force generated from the motor to the rolling roller and the conveyance roller. Each of these rotating shafts is supported by a bearing.
In these bearings, when fine wear powder or the like is generated during operation, the wear powder becomes a foreign matter and is mixed into the lubricating oil, causing troubles such as seizure. Further, if the bearing is used beyond the predetermined service life, breakage such as a crack is likely to occur.

  Conventionally, as a means of diagnosing the occurrence of serious damage to the bearing part, a means of measuring vibrations as an index of the plant operating state with a vibration sensor such as an accelerometer, or a material crack occurrence and progress with an AE sensor A means for measuring the generated elastic wave is used. Generally, these sensors are attached to a steel bearing box provided with a bearing.

JP-A-9-26414

As described above, the conventional abnormality diagnosis apparatus has a vibration sensor and an AE sensor mounted on a steel bearing box provided with a bearing in order to detect a serious damage of the bearing portion. However, the location where an abnormality such as a crack or wear occurs is not limited to the bearing, but rather a crack often occurs on the rotating shaft itself.
In other words, in the conventional vibration sensor and AE sensor attached to the bearing box, the elastic wave generated as a result of cracking or progressing of the material is received via the bearing part, so the signal sensed by the sensor is There was a problem that it was attenuated and an accurate diagnosis could not be made.

 To deal with this problem, Patent Document 1 proposes a wireless transmission system for AE signals in which an AE sensor is attached to a rotating body as shown in FIG. However, even with this method, the influence of noise on the radio signal is unavoidable, and there is still a problem with the accuracy of the sensor attached to the rotating body. In the figure, 101 is an AE sensor, 102 is a rotating body, 103 is a bearing, 104 is a machine base, 105 is a rotating shaft, 106 is a transmitting device, and 107 is a receiving device.

  The present invention has been developed in view of the above-described present situation, suppresses attenuation of a signal sensed by a sensor, receives an elastic wave signal accompanying the generation and progress of a crack on a rotating shaft via a liquid, and detects abnormalities. An object of the present invention is to provide an abnormality diagnosis apparatus capable of performing diagnosis with high accuracy together with a diagnosis method using the diagnosis apparatus.

That is, the gist configuration of the present invention is as follows.
(1) An apparatus for detecting an abnormality occurring in a rotating shaft, comprising at least one elastic wave detection means and an abnormality diagnosis means for diagnosing an abnormality based on the elastic wave detected by the elastic wave detection means, The elastic wave detecting means includes a liquid reservoir that stores a liquid that is in contact with a part of the rotating shaft, and an acoustic emission (AE) sensor that detects an elastic wave propagating through the liquid installed in contact with the liquid reservoir. The abnormality diagnosing means has a device for analyzing the detected elastic wave and a device for diagnosing an abnormality occurring in the rotating shaft from the analyzed elastic wave.

  (2) The elastic wave detecting means includes a disk-shaped ring attached to the rotating shaft, a liquid reservoir for storing liquid in contact with the ring, and an acoustic emission (AE) sensor. ) Is a rotating shaft abnormality diagnosis device.

  (3) The rotating shaft abnormality diagnosis apparatus according to (1), wherein the liquid in the liquid reservoir is a magnetic fluid, and a magnet for holding the magnetic fluid is attached to the liquid reservoir.

  (4) The abnormality diagnosis unit has a function of selecting an elastic wave to be analyzed among the elastic waves measured by the elastic wave detection unit, according to any one of (1) to (3), Rotation axis abnormality diagnosis device.

  (5) When detecting an abnormality occurring in the rotating shaft, the acoustic wave from the rotating shaft is detected by using an acoustic emission (AE) sensor of an elastic wave detecting means having a liquid reservoir for storing a liquid in contact with a part of the rotating shaft. An abnormality diagnosis method for a rotating shaft, characterized in that an abnormality occurring in the rotating shaft is diagnosed by detecting through the liquid and analyzing the detected elastic wave.

  (6) The elastic wave detecting means includes a disk-shaped ring attached to the rotating shaft, a liquid reservoir for storing a liquid in contact with the ring, and an acoustic emission (AE) sensor for detecting an elastic wave propagating through the liquid. The rotating shaft abnormality diagnosis method according to (5), characterized in that it is used.

  (7) The method for diagnosing an abnormality of the rotating shaft according to (5), wherein the liquid reservoir for storing the liquid in contact with a part of the rotating shaft uses a magnetic fluid as the liquid.

  (8) The abnormality diagnosis of the rotating shaft according to any one of (5) to (7), wherein an elastic wave to be analyzed is selected and analyzed among the elastic waves measured by the elastic wave detecting means. Method.

  According to the present invention, since the elastic wave propagating to the rotation axis can be directly detected, the attenuation of the signal is small, and noise during measurement is effectively eliminated by selecting the elastic wave to be analyzed. be able to. As a result, it is possible to accurately diagnose the abnormality of the rotating shaft.

FIG. 6 is a side view of a rotating facility provided with a wireless transmission type abnormality diagnosis device disclosed in Patent Document 1. It is a side view of a rolling mill provided with the abnormality diagnosis apparatus of the rotating shaft according to this invention. It is a system block diagram of the abnormality diagnosis apparatus of the rotating shaft according to this invention. It is the side view and AA arrow view showing the detailed structure of the liquid reservoir part of the abnormality diagnosis apparatus according to this invention. It is the side view and AA arrow directional view showing the detailed structure of the liquid reservoir part of the other abnormality diagnostic apparatus according to this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking as an example a rotating shaft of a steel rolling mill.
FIG. 2 is a side view showing a rotating shaft abnormality diagnosis apparatus according to the present invention. In the figure, 1a and 1b are rolling rolls, 2 is a material to be rolled, 3 is a bearing for supporting each rotating shaft, 4a and 4b are spindles, 5a and 5b are liquid reservoirs, and 6a and 6b are liquid reservoirs 5a. AE sensor installed in 5b. 7a and 7b are pinion gears, 8 is a reduction gear, and 9 is an electric motor.

  FIG. 3 is a system configuration diagram of the rotating shaft abnormality diagnosis apparatus according to the present invention. In the figure, reference numeral 20 denotes elastic wave detection means (the liquid reservoirs 5a and 5b and AE sensors 6a and 6b in FIG. 2), and 21 denotes a preamplifier. Further, 22 is provided with an AE analysis device 23 which is an abnormality diagnosis means, and a device 24 which receives a selection signal and diagnoses the analysis result.

As shown in FIG. 2, generally, in a steel rolling line, the output from the electric motor 9 is transmitted to the speed reducer 8 and is distributed up and down by the pinion gears 7a and 7b to drive the driving force to the spindles 4a and 4b. Is finally transmitted, the rolling rolls 1a and 1b are rotated, and the material 2 to be rolled is rolled. The lubricating oil reservoirs 5a and 5b are filled with a liquid such as a magnetic fluid, lubricating oil, or water so as to come into contact with the spindles 4a and 4b. In the present invention, a magnetic fluid is particularly suitable as the liquid that contacts the spindles 4a and 4b.
Further, AE sensors 6a and 6b for detecting elastic waves generated when an abnormality such as a crack occurs in the spindles 4a and 4b are attached to the liquid reservoirs 5a and 5b.

  As shown in FIG. 3, the output from the elastic wave detection means 20 is amplified via the preamplifier 21 and subjected to signal processing such as Fourier transform in the AE analysis device 23 in the abnormality diagnosis means 22. The When the selection signal is input, the diagnosis device 24 in the abnormality diagnosis means 22 performs analysis such as checking the selected elastic wave with the normal elastic wave obtained in advance.

  In the present invention, as described above, the diagnostic device 24 includes the spindles 4a and 4b by collating the selected elastic wave with the normal elastic wave obtained in advance for analysis. There is a function that can diagnose whether an abnormality has occurred. In other words, abnormalities can be diagnosed based on elastic wave data at an arbitrary timing, and as a result, noise during measurement, which was inevitable in the detection of elastic waves in the conventional method, is effectively eliminated, It is now possible to accurately diagnose abnormalities in the rotating shaft.

Here, the analysis in the present invention refers to a collation target for comparison with a normal elastic wave obtained in advance or a threshold value of an arbitrary management parameter obtained from a normal elastic wave. In addition, the above-described diagnosis function includes all operations that are performed until the equipment is stopped when the diagnosis device 24 diagnoses an abnormality. Is not limited to the function of automatically performing the diagnosis, for example, a diagnosis function for the final judgment of the worker, for example, a function for simply displaying a numerical value or the like for the worker to judge when an abnormality is diagnosed. In addition, a function of blinking this display or issuing an alarm or the like is also included.
The arbitrary management parameter includes the maximum value, rate of change, average value transition rate, etc. of the elastic wave, but any management parameter relating to a conventionally known vibration can be suitably used.

4 (a) and 4 (b) show a side view and a AA arrow view showing the detailed structure of the liquid reservoir of the abnormality diagnosis device according to the present invention. In the figure, 10 is a vibration-proof rubber, and 11 is a magnet such as a permanent magnet or an electromagnet.
As shown in FIG. 2A, the liquid reservoir 5a is attached to the housing of the speed reducer 8 via a vibration isolating rubber 10 that is not affected by vibration from the pinion gear 7a. The spindle 4a is arranged so that the magnetic fluid filled in the liquid reservoir 5a contacts. As shown in FIGS. 4A and 4B, there is a slight gap between the liquid reservoir 5a and the spindle 4a. When the magnetic fluid is used as a liquid, the liquid reservoir 5a is preferably made of metal so that the magnetic fluid filled in the liquid reservoir 5a does not spill from the gap, and the magnet 11 is placed at the boundary. Is installed. However, this is not a limitation on the type of liquid, and in the case of other liquids, a holding measure corresponding to the liquid may be taken.

FIGS. 5A and 5B are a side view and a AA arrow view showing the detailed structure of the liquid reservoir of the abnormality diagnosis apparatus when the disc-shaped ring according to the present invention is attached to the rotating shaft. In the figure, 12 is a ring.
As shown in FIG. 4A, the liquid reservoir 5a is attached to the housing of the speed reducer 8 via a vibration isolating rubber 10, as in the case of FIG. As shown in FIGS. 5A and 5B, a ring 12 is attached to the outer periphery of the spindle 4a and is in contact with the liquid reservoir 5a. For this reason, there is little risk of liquid spilling from the gap between the liquid reservoir 5a and the spindle 4a. Therefore, in this case, it is not necessary to install the magnet 11 and the liquid reservoir 5a does not have to be made of metal, and the liquid can be preferably a liquid such as a normal lubricant or water. is there.
In the above-described embodiment, the case where the elastic wave detecting means (liquid reservoir (oil bath)) is installed in the middle of the rotating shaft has been described. However, the elastic wave detecting means in the portion of the rotating shaft such as the end of the rotating shaft. There is no particular limitation on the installation position, and the number of installations is not particularly limited.

Next, an abnormality diagnosis procedure using the rotating shaft abnormality diagnosis apparatus according to the present invention will be described.
When a crack occurs during the operation of a rotating shaft, that is, a rotating shaft (spindle 4a and 4b) of an equipment having a spindle, for example, a steel rolling mill, an elastic wave accompanying the crack is generated. At this time, the signal from the elastic wave is amplified via the preamplifier 21 by the AE sensors 6a and 6b attached to the liquid reservoirs 5a and 5b, and is subjected to Fourier transform by the AE analyzer 23 in the abnormality diagnosis means 22. The signal processing is performed to diagnose the presence or absence of abnormality.

  Next, a selection signal is input to the diagnostic device 24. This signal may be input using an automatic device such as a program controller, or may be input when there is no load on the rotating shaft. The operator may input data with a selection switch or the like at an arbitrary timing.

  When this selection signal is input, the diagnosis device 24 analyzes and diagnoses whether an abnormality has occurred in the spindles 4a and 4b. At the time of this analysis, the above-mentioned data and the normal elastic wave obtained in advance are collated, but the collation etc. is not only the collation of the waveform but also the normal elasticity. In order to compare with a specific management value obtained from a wave, the selected elastic wave is processed and compared with the management value, and the method includes various conventionally known verification methods. Applicable, for example, by displaying numerical values etc. on the diagnostic device 24, the operator may compare and monitor with specific management values, and continue operation of the equipment, stop equipment, etc., or mechanically collate An alarm may be issued or the equipment may be stopped.

  In the above description, the rotating shaft of a rolling mill such as a magnetic steel sheet has been described as an example. However, the equipment having the rotating shaft has the same structure as the rotating shaft of this rolling mill. Needless to say, the present invention is not limited to the above-described equipment as long as it can be suitably used for equipment such as a fan and a blower and has a rotating shaft.

 A rotating shaft of a rolling mill that has reached a predetermined service life but has not yet cracked was prepared, and the same device as before was attached to one of the bearings in a steel bearing box. Moreover, the apparatus shown in FIG. 2 was attached to the other end of the shaft, and a simulated load and an unloading (release) were repeated. When the apparatus shown in FIG. 2 operated in accordance with the method of the present invention receives a signal indicating that an abnormality has been detected, the equipment is stopped and the above rotating shaft is inspected by a penetrant flaw test in accordance with JIS Z 2343. As a result, minute cracks were confirmed. At this time, the conventional apparatus did not sense any abnormality.

  According to the present invention, since an elastic wave signal associated with the occurrence and development of a crack on the rotating shaft can be directly received, the steel plant or the like equipped with a rotating shaft such as a rolling mill or a conveying line can be stably used. Operations can be carried out.

1a, 1b Roll 2 Roll material 3 Bearing of each rotating shaft
4a, 4b spindle
5a, 5b liquid reservoir
6a, 6b AE sensor
7a, 7b pinion gear 8 Reducer 9 Electric motor
10 Anti-vibration rubber
11 Magnet
12 rings
20 Elastic wave detection means
21 Preamplifier
22 Anomaly diagnosis means
23 AE analyzer
24 Diagnostic equipment
101 AE sensor
102 Rotating body
103 Bearing
104 stand
105 rotation axis
106 Transmitter
107 Receiver M Motor

Claims (8)

 An apparatus for detecting an abnormality occurring in a rotating shaft, comprising: at least one elastic wave detecting means; and an abnormality diagnosing means for diagnosing an abnormality based on the elastic wave detected by the elastic wave detecting means. The detection means includes a liquid reservoir that stores liquid in contact with a part of the rotating shaft, and an acoustic emission (AE) sensor that detects an elastic wave propagating through the liquid installed in contact with the liquid reservoir. The diagnostic means includes a device for analyzing the detected elastic wave and a device for diagnosing an abnormality that occurs in the rotary shaft from the analyzed elastic wave.   The said elastic wave detection means consists of the disk-shaped ring attached to the said rotating shaft, the liquid reservoir which stores the liquid which touches this ring, and an acoustic emission (AE) sensor, The acoustic emission (AE) sensor is characterized by the above-mentioned. Rotation axis abnormality diagnosis device.   2. The rotating shaft abnormality diagnosis apparatus according to claim 1, wherein the liquid in the liquid reservoir is a magnetic fluid, and a magnet for holding the magnetic fluid is attached to the liquid reservoir.   The said abnormality diagnosis means has a function which selects the elastic wave to analyze among the elastic waves measured in the elastic wave detection means, The abnormality diagnosis apparatus of the rotating shaft in any one of Claims 1-3 characterized by the above-mentioned. .   When detecting an abnormality occurring on the rotating shaft, the acoustic wave from the rotating shaft is transmitted through the liquid using the acoustic emission (AE) sensor of the elastic wave detecting means having a liquid reservoir that collects the liquid in contact with a part of the rotating shaft. And detecting an abnormality occurring in the rotating shaft by analyzing the detected elastic wave.   The elastic wave detecting means uses a disc-shaped ring attached to the rotating shaft, a liquid reservoir for storing a liquid in contact with the ring, and an acoustic emission (AE) sensor for detecting an elastic wave propagating through the liquid. 6. The method for diagnosing an abnormality of a rotating shaft according to claim 5.   6. The method for diagnosing an abnormality of a rotating shaft according to claim 5, wherein the liquid reservoir for storing the liquid in contact with a part of the rotating shaft uses a magnetic fluid as the liquid. 8. The rotating shaft abnormality diagnosis method according to claim 5, wherein an elastic wave to be analyzed is selected and analyzed among elastic waves measured by the elastic wave detecting means.

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