JPS6293620A - Diagnostic device for rotary machine - Google Patents

Abstract

PURPOSE:To enable the diagnosis of an abnormality cause on the spot in such a state that rotary machine equipment is operated, by performing the diagnosis of the abnormality cause by comparing the vibration spectrum pattern of the rotary machine equipment with that at the time of abnormality. CONSTITUTION:When the value obtained by amplifying the output of a vibration sensor 1 detecting the vibration of rotary machine equipment by a vibration amplifier 2 is larger than the reference value stored in a vibration control reference value memory 3, an abnormality judge device 4 judges the presence of abnormality. At this time, the output of the vibration amplifier 2 is analyzed by a FFT arithmetic unit 5 and this unit 5 outputs a vibration spectrum pattern. At this time, from the value set by a fundamental number-of-rotation setting device 8, a rolling bearing coefficient setting device 9 and a gear number-of- tooth setting device 10, a vibration spectrum pattern generated at the time of abnormality for discriminating the cause of abnormality is operated by an arithmetic part 11 calculating the frequency at the time of abnormality. Both spectrum patterns are compared by a vibration spectrum comparator 7 to judge the cause of abnormality.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an equipment diagnostic device that can diagnose the presence, location, and cause of abnormalities in mechanical equipment such as rotating equipment while it is in operation.

(Conventional technology) Equipment diagnosis technology has been recognized as effective in effectively proceeding with equipment maintenance work, and is becoming effective in on-site maintenance work.

Rotation (mechanical equipment, reciprocating machinery, etc.), which accounts for 7' failures in these equipment, means that if the overall value of the vibration becomes abnormally high compared to normal, it means that some kind of abnormality has occurred. is identified.

In other words, it is possible to know whether there is an abnormality based on the overall value of the vibration amplitude. 'Toru.

Furthermore, it is well known that in rotating machinery and equipment, it is possible to create a frequency spectrum pattern from the overall value of detected vibrations, thereby making it possible to specifically identify the cause of an abnormality in an object to be diagnosed.

(Problems to be solved by the invention) However, conventionally, abnormality diagnosis of this type of rotating mechanical equipment is
Bring a vibration recorder to the site and record the vibration data of the rotating mechanical equipment to be diagnosed. A spectrum analyzer is brought to the site and the vibration spectrum is analyzed, and the cause of the abnormality is diagnosed by recalling the vibration spectrum of abnormal rotating machinery and equipment.

With such a method, an expert in equipment diagnosis can easily diagnose the problem, but an unskilled person may not be able to make an accurate diagnosis.

An object of the present invention is to provide a movable rotating machine diagnostic device as one of the means for solving the problem of the current situation where equipment diagnostic technology is becoming widespread but there is a shortage of skilled personnel.

(Means for Solving the Problems) A rotating machine diagnostic device according to the present invention includes a vibration sensor that detects vibrations of a rotating machine equipment, an amplifying means that amplifies a detection signal of the vibration sensor, and a vibration sensor of the rotating machine equipment. a reference value setting means for setting a control reference value; an abnormality determination means for comparing the output of the amplification means with the vibration management reference value of the reference value setting means and determining that an abnormality exists when the former is larger than the latter; FFT calculation means that analyzes the output of the amplification means using fast Fourier transform (FFT) when the determination means determines that there is an abnormality, and various setting values such as the basic rotation speed necessary for vibration management of the rotation@mechanical equipment. a setting means for inputting a vibration frequency, a means for calculating a frequency of vibration occurring at an abnormal time based on a predetermined relationship from various setting values inputted by the setting means, and a means for calculating a vibration frequency occurring at an abnormal time based on a predetermined relationship from various setting values input by the setting means; When it is determined that there is
The vibration spectrum comparison means compares the vibration spectrum pattern calculated by the calculation means with the abnormal vibration spectrum pattern calculated by the abnormal vibration frequency calculation means to identify the cause of the abnormality.

(Function) The rotating machine diagnostic device according to the present invention is capable of calculating the vibration spectrum pattern at the time of an abnormality of the rotation/exit mechanical equipment using the setting means and the abnormality occurrence frequency calculation means. , the amplification means and the FFT calculation means 1) enables vibration dynamic vector analysis of the rotating mechanical equipment. The abnormality determining means determines whether there is an abnormality based on the magnitude of the vibration level.

When there is an abnormality, the vibration spectrum comparison means compares the vibration spectrum pattern of the rotating mechanical equipment with the vibration spectrum pattern at the time of the abnormality, and diagnoses the cause of the abnormality.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In this example, a rotating shaft, a rolling bearing, and a gear of rotating mechanical equipment are diagnosed.

Figure @1 shows a block diagram of an equipment diagnostic device according to an embodiment of the present invention. A vibration sensor (a piezoelectric acceleration sensor is used in this embodiment) 1 that is attached to rotating mechanical equipment and detects vibrations (displacement, speed, or acceleration) detects vibrations of the equipment and converts them into electrical signals. . If the mounting location is appropriate, it is possible to distinguish between f and Q whether the abnormal phenomenon is in the axial direction or the radial direction. Vibration amplifier 2 is vibration sensor 1
amplify the detected signal. The amplified value is converted into velocity and displacement by integration if necessary, and sent to an abnormality determiner 4 and an F'FT (fast Fourier transform) calculator 5.

On the other hand, the vibration management reference value memory 3 stores various reference values for determining whether or not the output value of the vibration amplifier 2 is abnormal. (This reference value may be a predetermined value, or may be determined by multiplying the standard deviation obtained from a plurality of measured values by a predetermined factor obtained empirically. In the latter case, A separate standard deviation calculation method is provided.)
The abnormality determiner 4 determines that there is an abnormality when the overall value of the velocity or acceleration obtained from the output of the vibration amplifier 2 is larger than this reference value, and sends a signal to the controller 6 and the outside. When the controller 6 receives this signal, it sends the signal to the FFT calculator 5, and the I'FT calculator 5 performs frequency analysis of the output of the vibration amplifier 2 by FFT. And FFT
The computing unit 5 sends the result (vibration spectrum pattern) to the vibration spectrum comparator 7.

Margin below On the other hand, if there is an abnormality in a rotating machine, as shown in Table 1, it is possible to determine the frequency of vibration that occurs in the abnormal location of the rotor, coupling, rolling bearing, sliding bearing, foundation, gear, etc. The frequency spectrum has a significant amplitude at the frequency corresponding to the cause of the abnormality. The abnormal vibration spectrum pattern for identifying the cause of the abnormality is determined from the values set in the basic rotation speed setting device 8, rolling bearing coefficient setting device 9, and gear tooth number setting device 11). The time frequency calculation unit 11 calculates the frequency based on the predetermined relationship shown in the table. Here, the basic rotation speed setting device 8 sets the rotation speed fo of the shaft to be diagnosed in the equipment, and the rolling bearing coefficient setting device 9 sets the number of rollers (1) the pitch diameter of the bearing (1) and the number of bearing balls. 7. Set the diameter d of the bearing ball and the contact angle α of the bearing, and use the gear tooth number setting device to set the number of gear teeth to 2. Note that the basic rotation speed setting device 8 may be replaced with a rotation speed meter that automatically detects the rotation speed of the axis to be diagnosed of the equipment, and the rotation speed may be automatically tracked.

Is vibration spectrum comparator 7 abnormal? When the Il constant device/t determines that an abnormality has occurred, it compares the vibration spectrum pattern of the equipment sent from the FFT calculator 5 with the vibration spectrum pattern obtained by the abnormality occurrence frequency calculation unit 11, and determines the cause of the abnormality. tlI in detail and send the results to the external (CRT
, printer, etc.).

The controller 6 determines each component described above.
``1.'' Operate sequentially in the following steps.

If you want to diagnose mechanical elements other than the rotating shaft, rolling bearings, and gears of rotating vibration equipment, such as cambling, sliding bearings, foundations, etc., use a setting device to set the setting values necessary for diagnosing each mechanical cable. is provided, the abnormal vibration frequency calculation unit 11 calculates a vibration spectrum pattern from these set values, and the vibration spectrum comparator 71,
This vibration spectrum pattern may be compared with the vibration spectrum pattern from the I'FT calculator 5 to determine the cause of the abnormality.

The remarkable spectral amplitude corresponding to the cause of the abnormality is rotation + a
1ij
As mentioned above. However, the problem with frequency spectrum analysis using fast Fourier transform is that if the frequency does not match an integer multiple of the decomposition frequency Δr determined by the vibration amplifier 2 and the FFT calculator 5, it will be interpreted as a single line spectrum. This is something that must not be done. In this case, even though the vibration force is originally a single line spectrum, the result of frequency spectrum analysis is calculated as a combination of many line spectra in the vicinity of the vibration input frequency. Shih
However, if a large number of line spectra are combined as is, the true amplitude value cannot be easily read.

Therefore, in this example, the inventors of the present invention
The method used in Japanese Patent No. 039521 was adopted. In this method, spectrum analysis is performed using the FFT method, the magnitude of the frequency spectrum values obtained as a result is determined, and the upper value including the maximum value, for example, 10411, is selected.
The basic feature is that after lvi, for example, 10 sets of amplitude values are selected and the sum of squares square root calculation is performed on the selected t amplitude values.

FIG. 3 is a block diagram of the FFT calculator 5.

The Dinotal frequency spectrum analysis calculator 21 performs frequency spectrum analysis of the digital signal converted by the analog/Dinotal converter 3 by fast Fourier transform. The spectral amplitude magnitude discriminator 22 determines the magnitude of the spectral amplitude obtained by the Dinotal frequency spectrum analysis calculator 21, and selects, for example, 10 sets of amplitude values in descending order of magnitude. The sum-of-squares square root calculator 23 is
frequency p, which is obtained by the amplitude size discriminator 22 and gives the maximum amplitude value. Decomposed frequency Δ centered on
The most probable maximum amplitude value is calculated from the amplitude values in the range of ±nΔ (where positive integers of at least 3 or more) at intervals of (for example, I Hz) by square root calculation of the sum of squares. As a result, the vibration frequency spectrum amplitude of the rotating machine to be diagnosed can be obtained with an approximation of about 98% or more.

That is, for example, 1 before and after the adjacent one containing the selected frequency.
When the above-mentioned sum of squares square root is executed from the zero set of frequency spectra, the maximum amplitude value in the frequency spectrum of vibrations generated by the rotating machine will be approximately shown. The frequency that gives the second largest amplitude value is also analyzed in the same way.

FIG. 3 shows the diagnosis 70-. Assume that a vibration sensor 1 that detects a raw waveform of vibration is used. The raw waveform of the detected vibration (step Sl) is amplified by the vibration amplifier 2, and then the velocity value and acceleration value of the vibration are respectively calculated (
Step S2. S3).

Then, overall values of velocity and acceleration are respectively calculated (steps S4 and S5). The former is used to determine whether there is an abnormality in a predetermined rotating shaft, etc., and the latter is used to determine whether there is an abnormality in a rolling bearing, a gear, etc. The abnormality determiner 4 constantly monitors whether the overall speed value and the overall acceleration value are each larger than a predetermined reference value (step S6). When it is determined that there is an abnormality, a signal is sent to the FFT calculator 5 to perform FFT calculation K (step S7). The vibration spectrum comparator 7 compares the vibration spectrum pattern obtained by the FFT calculation with the vibration spectrum pattern at the time of abnormality, and determines the cause of the abnormality (step S8).

Here, we have shown the flow for detecting the raw waveform of vibration, but when measuring the velocity and acceleration of vibration, the raw waveform (vibration), velocity, and acceleration can be mutually converted using differentiation and integration. It is possible to perform diagnosis by converting it as appropriate.

Table 2 in the margin below.Next, specific examples of abnormality diagnosis are shown. When diagnosing abnormalities in mechanical parts, the frequency of the motor or machine to be diagnosed [.

, 2f, and 3". (". is the shaft rotational speed). Here, the basic rotational speed f0 is the rotational speed of the rotor. As shown in the example in Table 2, the basic rotational It is possible to determine the operating status of small, medium-sized, and large-sized machines, respectively.In other words, as the overall value of vibration speed increases from O, the operating status changes from A (good) to B. (slightly good), C (slightly bad),
It changes sequentially from D (bad). In the case of C and D,
Value A of the vibration spectrum at frequencies 1°, 2f, 3fo
, A, Find A, 7f, 2f, 3f
.

Compare each vibration speed with the overall value to determine the cause of the abnormality.

FIG. 4 shows the abnormality diagnosis 70- of the mechanical part in more detail. Basic rotation speed f. is set by the basic rotation speed setting device 8. First, vibration of a vibration target is detected (step 511). Next, the overall value of vibration speed (X
, ) is calculated (step 512).

Next, it is determined whether the overall value (X,) exceeds the reference value (Xr) (step 513).

If it does not exceed the limit, it is determined that there is no abnormality (step 51).
4).

Here, the reference value was set from the calculated value. An example of this will be explained next. Table 3 shows past X. The measured value is shown. From this X management data, first, each measured value is divided into two groups of data. The range R1 of X Ll for each group and its average value R (0.70/8=0.09 here) are determined. Also, calculate the average value X of ×1. Then, the reference value Xr is determined from the following formula.

Xr=X+A−R Here, A is usually selected in the range of 1 to 5. Here, A'' is set to 2.66. Therefore, Xr=0.68.

Table 3 below: In step S13, the overall value X of the vibration speed. If exceeds the reference value Xr, perform FFT calculation from the vibration velocity data and calculate the vibration frequency "., 2F, .
: Vibration speed X(r,) at H,.

Find X(2fo), X(3f,) (step 515
).

Next, it is determined whether the vibration velocity x (ro> exceeds AIXr) (step 521). Here, A1 is from 0 to 1.
For example, it is a constant within the range of 1/3.

If not, it is determined that the abnormality is other than a mechanical defect (imbalance and misalignment) (step 52).
2) Next, it is determined whether the vibration speed×(2L) exceeds A 2X r (step S23). Here, A
2 is a constant in the range from O to 1, for example, 1
/6. If it exceeds, then vibration speed X (3L)
It is determined whether or not exceeds A 3 X r (step 524). If it exceeds, it is determined that there is a misalignment (step S25); if not, it is determined that there is a misalignment or (soil imbalance) (step S25).
. If it is determined no in step S23, then X(
], ) exceeds A, Xr (step 527). If it exceeds, it is determined that there is poor balance or misalignment (step 828); if not,
It is determined that the balance is poor (step 529).

In addition, Fig. 5 shows 70 points of abnormality diagnosis for rolling wheel bearings.
- indicates. When an inner ring flaw, an outer ring flaw, or a single flaw occurs on a rolling bearing, the vibration frequency (
Below, r! Vibration occurs at the "ouL" (also called "ouL"). Therefore, the vibration frequency ", [.

The vibration spectrum values Ai + AoT Ab at + out are compared with the reference value, and if the reference value is -], it is determined that there is an abnormality, and the cause of the abnormality is identified.

First, the vibration frequencies r caused by inner ring scratches, outer ring scratches, and one scratch,
, r. ,,[, are the pitch roundness, ball scratch d, and number of balls N inputted in the rolling bearing coefficient setting device 9.

Contact angle a and shaft rotation speed r. Calculations are then made using the formulas in Table 1 (step 531).

Next, detect the acceleration of the vibration to be diagnosed (step S
32). Then, an overall value Y of acceleration is detected (step 533).

Next, it is determined whether the overall value Y exceeds the reference value Y (step 534). Here, the reference value Y is determined from conventional measured values, although it will not be explained in detail. If not, it is determined that there is no abnormality (step 5
35).

If it exceeds, perform FFT calculation from the acceleration data,
Frequency [; , ro, t + r b teno acceleration Y
(ri)Y(f), Y<f, ) is determined (step 836).

ut Next, whether or not the acceleration Y(L) exceeds B, Y is 1
1 "In other words, determine whether or not an internal injury has occurred (Step 5)
41). Here, B is a constant within the range from 0 to 1, for example, 1/3. If it is over, then Y
(rout) is B. It is determined whether or not Yr has been exceeded, that is, whether or not an outer ring damage has occurred (step 542). Here, B is a constant within the range from 0 to 1, for example, 1/3. If it exceeds, then it is determined whether Y(fb) exceeds BbYr, that is, whether one scratch has occurred (step 543). If it exceeds, it is determined that either an inner ring wound, an outer ring wound, or a single wound has occurred (step 544); if not, it is determined that an inner ring wound or an outer ring wound has occurred (step 545).

If it is determined no in step S41, then Y(
fou,) is B. It is determined whether Yr has been exceeded (step 846). If it exceeds, then Y(rb) becomes B
It is determined whether or not the value exceeds bY (step 547).

If it exceeds, it is determined that an outer ring scratch and one scratch have occurred (step 848), and if not, it is determined that an outer ring scratch has occurred (step 549). If it is determined no in step 346, then it is determined whether Y(f, ,) exceeds BbY (step 550).

If it exceeds, it is determined that one scratch has occurred, step S5.
1), if no, it is determined that the cause is unknown (step 5).
52).

If it is determined no in step S42, then Y
It is determined whether (fb) exceeds BbYr (step 553). If it exceeds, it is determined that an inner ring scratch and one scratch have occurred (step 554), and if not, it is determined that an inner ring scratch has occurred (step 555).

Furthermore, FIG. 6 shows the flow of abnormality diagnosis in the case of gears. When eccentricity, local abnormality, wear, uneven contact, etc. occur in a gear, an abnormality occurs at the meshing frequency ~ shown in the frequency of occurrence in Table 1. Therefore, the value of the vibration spectrum at the frequency rg is compared with the reference value C, and if it is larger than the reference value, it is determined that there is an abnormality, and the cause of the abnormality is determined.

First, the frequency fg generated due to eccentricity etc. is determined by the gear tooth number setting device 1.
The number of teeth Z゛up and the number of rotations f inputted at 0. Calculate using the formula in table @1 (step 561)
.

Next, vibration of the object to be diagnosed is detected (step 562).

And the overall value U of acceleration.

is detected (step 563).

Next, the overall value U. It is determined whether or not exceeds the reference value Ur (step 564). Here, the standard value U,
Although not explained in detail, is determined from conventional measurement values.

If not, it is determined that there is no abnormality (step 565).

If it exceeds, perform FFT calculation from the acceleration data,
Frequency r and acceleration U(fg) at ``.

Find u(r.) (step 871).

Next, it is determined whether the acceleration tJ(fg) exceeds CgU (step 872), where Cg is a constant within the range of 0 to 1, and is set to 1/3, for example.

If not, it is determined that the cause of the abnormality is unknown (step 573). If it exceeds, then U(f8) is C8U
Determine whether rl has been exceeded (step 574)
. Here, Url is a reference value for vibration at a frequency of 1°, and although not explained in detail, it is determined from conventional measured values. co is a constant within the range from 0 to 1, for example, 1/3. If it exceeds, it is determined that eccentricity or local abnormality has occurred (Step 575); if not, it is determined that abnormality such as wear or uneven contact has occurred (Step 8).
76).

(Effects of the Invention) According to the present invention, the presence, location, and cause of abnormality can be diagnosed on site while mechanical equipment such as rotating equipment is in operation.

This helps in efficient maintenance work, reduction in repair costs, and improvement in the operating rate of the equipment.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the invention. FIG. 2 is a block diagram of the FFT calculator. 3 to 6 are respectively 70-diagrams of abnormality diagnosis. 1... Vibration sensor, 2... Vibration amplifier, 3...
・Vibration management reference value memory, 4... Abnormality determination device, 5... FFT calculator, 6...
・Controller, 7... Vibration spectrum comparator, 8
~10...Various setting devices, 11...Vibration frequency calculation unit that occurs during abnormality. Patent Applicant: Kawasaki Steel Corporation Kawatetsu Keiki Co., Ltd. Agent Patent Attorney: Aobai Ao and 2 others Figure 3

Claims (6)

[Claims] (1) A vibration sensor that detects vibrations of rotating mechanical equipment, an amplifying means that amplifies a detection signal of the vibration sensor, a reference value setting means that sets a vibration management reference value of the rotating mechanical equipment, and an output of the amplifying means. , an abnormality determining means that compares the vibration management reference value of the reference value setting means and determines that an abnormality exists when the former is larger than the latter; FFT calculation means for analysis using Fourier transform (FFT), setting means for inputting various setting values such as basic rotation speed necessary for vibration management of the rotating mechanical equipment, and various settings inputted by the setting means. Abnormal frequency frequency calculation means for calculating a vibration spectrum pattern during abnormality based on a predetermined relationship from the values, and when the abnormality determination means determines that there is an abnormality, the vibration spectrum pattern calculated by the FFT calculation means is calculated as the vibration occurring during abnormality. A rotating machine diagnostic device comprising vibration spectrum comparison means for comparing abnormal vibration spectrum patterns calculated by a numerical calculation means and determining the cause of the abnormality. (2) The rotating machine diagnostic device according to claim 1, wherein the vibration sensor is a piezoelectric acceleration detector. (3) In the rotating machine diagnostic device recited in claim 1, the setting means includes the pitch diameter of the rolling bearing of the rotating machinery equipment, the number of balls in the bearing, the diameter of the bearing balls, and the diameter of the bearing. A rotating machine diagnostic device equipped with a setting device for setting the contact angle. (4) The rotating machine diagnostic device according to claim 1, wherein the setting means includes a setting device for setting the number of teeth of the gear of the rotating mechanical equipment. (5) The rotating machine diagnostic device according to claim 1, wherein the setting means includes a tachometer that automatically detects the rotation speed of the axis to be diagnosed. (6) In the rotating machine diagnostic device set forth in claim 1, the reference value setting means includes a storage means for storing past output values of the amplifying means, and the vibration management reference value is A rotating machine diagnostic device that is set based on the output value using a predetermined relational expression.