WO2018088564A1

WO2018088564A1 - Bearing abnormality diagnostic method and diagnostic system

Info

Publication number: WO2018088564A1
Application number: PCT/JP2017/040835
Authority: WO
Inventors: 一弘吉田
Original assignee: 日本精工株式会社
Priority date: 2016-11-14
Filing date: 2017-11-14
Publication date: 2018-05-17

Abstract

Provided is a bearing abnormality diagnostic method that comprises: a vibration acceleration sensor (12) that detects vibration acceleration generated from a bearing (11); a plurality of bandpass filters (213), in the number needed for a plurality of different diagnoses, that respectively extract diagnostic signals of different frequency bands; and diagnostic units (22) that diagnose a plurality of types of abnormalities of the bearing (11), on the basis of the plurality of diagnostic signals extracted by the bandpass filters (213).

Description

Bearing abnormality diagnosis method and diagnosis system

The present invention relates to a bearing abnormality diagnosis method and diagnosis system, and more particularly, to a bearing abnormality diagnosis method and diagnosis system that can diagnose the presence or absence of an abnormality without disassembling mechanical equipment.

Conventionally, for example, as seen in Patent Document 1, in order to determine whether or not there is an abnormality in a rolling bearing, a detection device that detects vibration associated with the rotation of the rolling bearing and a signal that represents vibration detected by the detection device are at least Branches into two signals, and based on one of the signals, the presence / absence of damage of the rolling bearing and the damaged member are determined, and the amount of foreign matter mixed in the lubricant is determined based on the other signal. There is known a rolling bearing abnormality determination apparatus or determination method including an arithmetic processing unit that determines whether or not there is an abnormality in the rolling bearing based on at least the results of both of these determinations.

Japanese Unexamined Patent Publication No. 2009-109267

However, in the rolling bearing abnormality determination device or determination method described in Patent Document 1, the determination method is complicated because the presence or absence of abnormality is determined based on two determination results.

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a bearing abnormality diagnosis method and a diagnosis system capable of diagnosing a plurality of types of abnormality of the bearing by a simple determination method.

The above object of the present invention can be achieved by the following constitution.
(1) The vibration acceleration generated from the bearing is detected by a vibration acceleration sensor, and the number of frequencies required for a plurality of different diagnoses is determined by a plurality of bandpass filters from the vibration acceleration signal from the vibration acceleration sensor. A bearing abnormality diagnosis method comprising: extracting diagnostic signals having different bands and diagnosing a plurality of types of abnormality of the bearing based on the extracted different diagnostic signals.
(2) The bearing according to (1), wherein diagnosis of a plurality of types of abnormality of the bearing is performed based on frequency spectra obtained by frequency analysis of the plurality of different diagnostic signals. Abnormal diagnosis method.
(3) The vibration acceleration sensor is attached to a bearing housing that supports the bearing, and detects vibration acceleration generated from the bearing through the bearing housing. (1) or (2) Bearing abnormality diagnosis method.
(4) a vibration acceleration sensor for detecting vibration acceleration generated from the bearing;
A plurality of band-pass filters for extracting diagnostic signals having different frequency bands, each of which is required for a plurality of different diagnoses, from vibration acceleration signals from the vibration acceleration sensor;
Based on a plurality of diagnostic signals extracted by the bandpass filter, a diagnostic unit for diagnosing a plurality of types of abnormality of the bearing;
A bearing abnormality diagnosis system characterized by comprising:
(5) The bearing according to (4), wherein diagnosis of a plurality of types of abnormality of the bearing is performed based on frequency spectra obtained by frequency analysis of the plurality of different diagnostic signals. Abnormality diagnosis system.
(6) The vibration acceleration sensor is attached to a bearing housing that supports the bearing, and detects vibration acceleration generated from the bearing through the bearing housing. Bearing abnormality diagnosis system.

According to the present invention, it is possible to easily perform a plurality of different diagnoses by extracting a plurality of different diagnostic signals from the vibration acceleration signals of the vibration acceleration sensor that detects the vibration acceleration of the bearing. As a result, the type of failure can be determined, and the bearing that needs to be replaced can be replaced at a necessary timing, so that maintenance efficiency can be improved.
In addition, since a plurality of types of diagnosis can be performed with a single vibration acceleration signal, it is possible to diagnose even if failures occur simultaneously and frequently.

1 is a block diagram illustrating a schematic configuration of a bearing abnormality diagnosis system according to an embodiment of the present invention. It is a block diagram which shows the function structure of the diagnostic apparatus which concerns on this embodiment. It is a flowchart for demonstrating the operation | movement procedure of the bearing abnormality diagnostic system which concerns on this embodiment. It is a table | surface which shows the relationship between the site | part of the damage | wound of the rolling bearing which concerns on this embodiment, and the vibration frequency which arises resulting from a damage | wound. (A) is an example of a vibration acceleration signal from a vibration acceleration sensor, (b) and (c) are examples of diagnostic signals, and (d), (e), (f), and (g) are examples of spectral data. is there.

Hereinafter, an embodiment of a bearing abnormality diagnosis method and a diagnosis system according to the present invention will be described in detail with reference to the drawings.

The bearing abnormality diagnosis system of the present embodiment shown in FIG. 1 diagnoses an abnormality of the rolling bearing 11 that is a rotating component supported by the bearing housing 10, and detects vibration acceleration generated from the rolling bearing 11. The acceleration sensor 12, a rotation sensor (not shown) for detecting the rotation speed of the rolling bearing 11, and signals detected by the vibration acceleration sensor 12 and the rotation sensor are received via the data transmission means (transmission means) 13. A signal input unit 21 that performs filter processing and sends it to the subsequent diagnosis unit 22; a diagnosis unit 22 that diagnoses whether there is an abnormality in the rolling bearing 11 based on a signal from the signal input unit 21; a monitor or an alarm device Etc., and an output device 30 comprising the above.
The signal input unit 21 and the diagnosis unit 22 constitute a diagnosis device 20.

The rolling bearing 11 includes an inner ring 111 that is externally fitted to the rotating shaft 101 of the mechanical equipment, an outer ring 112 that is internally fitted to the bearing housing 10, and a plurality of rolling rings that are arranged to be able to roll between the inner ring 111 and the outer ring 112. It has the moving body 113 and the holder | retainer not shown which hold | maintains the rolling body 113 so that rolling is possible.

The vibration acceleration sensor 12 is fixed to the bearing housing 10 that supports the bearing 11. The method for fixing the vibration acceleration sensor 12 includes bolt fixing, adhesion, combined use of bolt fixing and adhesion, and embedding with a resin material.
In addition, in the case of bolt fixation, you may make it provide a rotation stop function. In addition, by molding the vibration acceleration sensor 12 with a resin material, it is possible to prevent moisture from entering, and further to improve the anti-vibration performance against external vibration, thus dramatically improving the reliability of the sensor itself. can do.

FIG. 2 is a block diagram showing the main functional configuration of the diagnostic apparatus 20 according to this embodiment.
As illustrated in FIG. 2, the diagnostic device 20 includes a data collection / distribution unit 211, a rotation analysis unit 212, a filter processing unit 213, a vibration analysis unit 214, a comparison determination unit 215, and an internal memory 216. The data collection / distribution unit 211 and the filter processing unit 213 mainly constitute the signal input unit 21, and the rotation analysis unit 212, the vibration analysis unit 214, the comparison determination unit 215, and the internal memory 216 mainly constitute the diagnosis unit 22. To do. In the present embodiment, a plurality of filter processing units 213 and diagnosis units 22 are provided in association with each other (see FIG. 1).
The diagnostic device 20 is constituted by a microcomputer, and each processing unit such as the data collection / distribution unit 211 executes the following processing by executing a program recorded and held in the microcomputer. Will be executed.

The data collection / distribution unit 211 converts the signal Sig1 sent from the vibration acceleration sensor 12 into a digital signal by an A / D converter, and simultaneously collects and temporarily accumulates a signal related to the rotational speed, and sets the signal type. In response, it is distributed to either the rotation analysis unit 212 or the filter processing unit 213.
Note that the A / D converter may be integrated with the vibration acceleration sensor 12, and a digital signal may be received via the data transmission means 13 described above.

The rotation analysis unit 212 is caused by damage for each part of the rolling bearing 11 using the predetermined relational expression shown in FIG. 4 based on the design specification data of the rolling bearing 11 and the rotation speed signal from the rotation sensor. Calculate bearing damage frequency.
The calculation of the bearing damage theoretical frequency may use past data stored in the internal memory 216 if a similar diagnosis has been performed previously.
In the case where the rotational speed detecting means (not shown) for detecting the rotational speed of the rolling bearing 11 is constituted by an encoder attached to the inner ring 111 and a magnet or a magnetic detection element attached to the outer ring 112. The output signal is a pulse signal corresponding to the shape and rotational speed of the encoder. Therefore, the rotation analysis unit 212 has a predetermined conversion function or conversion table corresponding to the shape of the encoder, and calculates the rotation speed of the inner ring 111 from the pulse signal.

The filter processing unit 213 has a function of a bandpass filter (BPF), divides the vibration acceleration signal Sig1 of the vibration acceleration sensor 12 into a plurality of different filter frequency bands for diagnosis, and a plurality of diagnosis signals (Sig2). -1, Sig2-2) is extracted. The filter frequency band to be extracted is set according to the natural frequency band in each bearing device. This natural frequency can be easily obtained by exciting the object to be measured by an impact method using an impulse hammer or the like, and analyzing the frequency of the vibration detector attached to the object to be measured or the sound generated by the impact. it can.
When the object to be measured is the rolling bearing 11, a natural frequency due to any of the inner ring 111, the outer ring 112, the rolling element 113, the bearing housing 10, and the like is given. In general, there are a plurality of natural frequencies of mechanical parts, and the amplitude level at the natural frequency is high, so the sensitivity of measurement is good.
The number of diagnostic signals in the present embodiment is two, but can be three or more as will be described later.

The frequency band of the diagnostic signal to be extracted from the vibration acceleration signal Sig1 should be appropriately set according to the natural frequency band of each bearing device (bearing 11 and bearing housing 10), the type of abnormality to be diagnosed, diagnostic conditions, and the like. Can do. The illustrated diagnostic signal Sig2-1 is for diagnosing an abnormality A described later, and its frequency band is set to 1K to 2K (Hz), and the diagnostic signal Sig2-2 is for diagnosing an abnormality B described later. The frequency band is set to 3K-4K (Hz).
In FIGS. 5A, 5B, and 5C, the horizontal axis f is the frequency (Hz), and the vertical axis G is the acceleration (m / s ² ).

The vibration analysis unit 214 performs frequency analysis of the vibration signal generated from the rolling bearing 11 based on the diagnostic signals (Sig2-1, Sig2-2) from the filter processing unit 213. The vibration analysis unit 214 is an FFT calculation unit that calculates the frequency spectrum of the vibration signal, and calculates the frequency spectrum of the vibration signal based on the FFT algorithm and envelope analysis. The calculated frequency spectrum is output to the comparison / determination unit 215 as spectrum data as shown in FIG. 5 (d) or FIG. 5 (e) and FIG. 5 (f) or FIG. 5 (g), for example.
Note that the vibration analysis unit 214 may perform absolute value processing and envelope processing as preprocessing for performing FFT, and convert only to frequency components necessary for abnormality diagnosis. Further, if necessary, the spectrum data after the envelope processing (envelope frequency spectrum) can also be output to the comparison determination unit 215 together.

The comparison / determination unit 215 diagnoses the abnormality of the bearing 11 as follows, for example, using the spectrum data obtained by the vibration analysis unit 214 as shown in FIGS. 5D to 5G, for example.

When the rolling element passing vibration as shown in, for example, FIG. 5D is detected in the spectrum data obtained based on the diagnostic signal Sig2-1 described above, the bearing calculated by the rotation analysis unit 212 is used. Based on the damage frequency, the bearing 11 is diagnosed as having some abnormality A (for example, damage to the outer ring raceway surface).
On the other hand, when the spectral data obtained based on the diagnostic signal Sig2-1 is such that the rolling element passing vibration is not detected, as shown in FIG. Diagnose it.

Further, when the rolling element passing vibration as shown in FIG. 5F is detected in the spectrum data obtained based on the above-described diagnostic signal Sig2-2, it is calculated by the rotation analysis unit 212. The bearing 11 is diagnosed as having some abnormality B (for example, wear on the outer ring raceway surface) different from the abnormality A on the bearing 11.
On the other hand, when the spectrum data obtained based on the diagnostic signal Sig2-2 is such that rolling element passing vibration is not detected, as shown in FIG. Diagnose it.
For abnormality diagnosis, vibration frequency generated with rotation of the bearing, such as rolling element passing vibration frequency, rolling element revolution frequency, and rolling element rotation frequency, can be used as a diagnostic index to detect and diagnose the behavior when an abnormality occurs.
In other words, by providing a plurality of filter processing units (bandpass filters) 213 for each type of failure to be detected in advance for one sensor signal, it is possible to detect rolling element passing vibrations by envelope analysis at the diagnosis unit. The presence and type of failure can be detected.
For this reason, conventionally, when an abnormality was diagnosed by an envelope analysis or the like, the bearing was sometimes replaced at an earlier stage than necessary in accordance with a failure that could not be rotated at the earliest priority given priority to safety. In this embodiment, since the type of failure can also be determined, a bearing that needs to be replaced can be replaced at a necessary timing.
In addition, it is possible to determine the type of bearing failure even if failures occur simultaneously.

The diagnosis result of the rolling bearing 11 determined as described above is stored in the internal memory 216 and sent to the output device 30 by the data transmission means 31 using wireless considering the wired or network.

The internal memory 216 is constituted by, for example, a memory or an HDD, and the design specification data of each rotating part used for calculation of the abnormal frequency, diagnosis of presence / absence of the abnormality of the rolling bearing 11 determined by the comparison determination unit 215, and abnormality detection Each piece of data relating to site identification is stored.

The output device 30 displays the diagnosis result of the rolling bearing 11 on a monitor or the like in real time. In addition, when an abnormality is detected, an alarm device such as a light or a buzzer may be used to alert the user of the abnormality.
The signal data transmission means 13 and 31 need only be capable of transmitting and receiving signals accurately, and may be wired or may be wireless considering the network.

Next, the operation of the bearing abnormality diagnosis system configured as described above will be described. FIG. 3 is a flowchart for explaining an operation procedure of the bearing abnormality diagnosis system.

First, in step S1, the vibration acceleration sensor 12 detects the vibration acceleration generated from the rolling bearing 11 and the rotation sensor detects the rotation speed of the rolling bearing 11, and the detected vibration acceleration signal and rotation speed signal are used as data transmission means 13. To the data collection / distribution unit 211 of the signal input unit 21.

The data collection / distribution unit 211 amplifies the input analog vibration signal as necessary, and converts it into a digital signal by an A / D converter.

Next, in step S2, based on the data stored in the data collection / distribution unit 211 and the internal memory 216, the filter processing unit 213 extracts a diagnostic signal used for the subsequent diagnosis.

Next, in step S3, the vibration analysis unit 214 performs frequency analysis of the vibration signal generated from the rolling bearing 11 based on the diagnostic signals (Sig2-1, Sig2-2) from the filter processing unit 213, and The frequency spectrum is calculated and the spectrum data is output to the comparison / determination unit 215.

In step S4, the comparison / determination unit 215 diagnoses the presence / absence and type of the bearing 11 by comparing the peak frequency of the spectrum data obtained by the vibration analysis unit 214 with the calculated bearing damage frequency, The result is sent to the output device 30 in step S5.

According to the bearing abnormality diagnosis method or diagnosis system as described above, the following effects can be obtained.
(A) By extracting a plurality of different diagnostic signals (Sig2-1, Sig2-2) from the vibration acceleration signal (Sig1) of the vibration acceleration sensor 12 that detects the vibration acceleration of the bearing housing 10 that supports the bearing 11, A plurality of different diagnoses can be easily performed. As a result, the type of failure can be determined, and the bearing that needs to be replaced can be replaced at a necessary timing, so that maintenance efficiency can be improved.
(B) Since a plurality of types of diagnosis can be performed with one vibration acceleration signal (Sig1), it is possible to diagnose even if failures occur simultaneously and frequently.

In addition, this invention is not limited to what was illustrated to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, the band set value, the diagnostic index, and the number of corresponding failures are not limited to this, and can be optimally set according to the target bearing, the failure to be detected, the diagnostic conditions, the required specifications, and the like. In addition to the damage and wear of the outer ring of the above embodiment, the detected abnormality includes bearing inner ring, outer ring, scratches on the rolling element, impressions, dents, rust, flaking, and the inner ring of the rolling element. Or a collision with a cage, a collision with a rolling element or a raceway of a cage, a collision between a cage and a rolling element due to grease resistance, friction of a contact portion of a seal, and the like.
Moreover, the bearing abnormality diagnosis method or diagnosis system of the present invention can be applied to machine equipment such as automobiles, railway vehicles, machine tools, wind power generators, and elevator devices.
In the present embodiment, the case of diagnosing the abnormality of the rolling bearing in the case of the inner ring rotation has been mainly described. However, the bearing abnormality diagnosis method or diagnosis system of the present invention monitors the state of the rolling bearing in the outer ring rotation. Is also applicable.

Furthermore, in the above embodiment, a vibration acceleration sensor is attached to the bearing housing and vibration acceleration generated from the bearing is detected via the bearing housing. However, the present invention is not limited to this, and vibration generated from the bearing. The vibration acceleration sensor may be attached at an arbitrary position where acceleration can be detected. For example, the vibration acceleration sensor may be directly attached to a stationary wheel.

This application is based on Japanese Patent Application No. 2016-22214 filed on November 14, 2016, the contents of which are incorporated herein by reference.

10 Bearing housing 11 Rolling bearing (bearing)
DESCRIPTION OF SYMBOLS 12 Vibration acceleration sensor 20 Diagnostic apparatus 21 Signal input part 213 Filter process part (band pass filter)
Diagnostic department

Claims

The vibration acceleration generated from the bearing is detected by a vibration acceleration sensor, and the number of frequencies required for a plurality of different diagnoses by a plurality of bandpass filters is different from the vibration acceleration signal from the vibration acceleration sensor. A bearing abnormality diagnosis method comprising: extracting a diagnosis signal and diagnosing a plurality of types of abnormality of the bearing based on the extracted different diagnosis signals.
2. The bearing abnormality diagnosis method according to claim 1, wherein diagnosis of a plurality of types of abnormality of the bearing is performed based on frequency spectra obtained by frequency analysis of the plurality of different diagnosis signals. .
The bearing abnormality diagnosis method according to claim 1, wherein the vibration acceleration sensor is attached to a bearing housing that supports the bearing, and detects vibration acceleration generated from the bearing through the bearing housing. .
A vibration acceleration sensor for detecting vibration acceleration generated from the bearing;
A plurality of band-pass filters for extracting diagnostic signals having different frequency bands, each of which is required for a plurality of different diagnoses, from vibration acceleration signals from the vibration acceleration sensor;
Based on a plurality of diagnostic signals extracted by the bandpass filter, a diagnostic unit for diagnosing a plurality of types of abnormality of the bearing;
A bearing abnormality diagnosis system characterized by comprising:
The bearing abnormality diagnosis system according to claim 4, wherein diagnosis of a plurality of types of abnormality of the bearing is performed based on frequency spectra obtained by frequency analysis of the plurality of different diagnosis signals. .
The bearing abnormality diagnosis system according to claim 4, wherein the vibration acceleration sensor is attached to a bearing housing that supports the bearing, and detects vibration acceleration generated from the bearing through the bearing housing. .