SU1698669A1 - Device for rolling bearings diagnostics - Google Patents

Abstract

The invention relates to a measurement technique, in particular, to devices for diagnosing defects in rolling bearings. The goal is to improve the accuracy of determining bearing defects. Accuracy increase is achieved by restoring the amplitude and frequency values of the vibration spectrum corresponding to the constant operating frequency of the bearing and the oscillatory system of the monitored bearing - a test bench with a single transfer function in the field of information frequencies. In the proposed device, the bearing is rotated at a constant operating frequency, a coasting mode is created by disconnecting the power from the test bench, and the amplitude of the vibration signal transmitted through the narrow band is measured by a vibration sensor. filter, and by means of a frequency meter, the instantaneous value of the frequency of rotation of the bearing. The obtained amplitude and rotation frequency are recalculated using a splitter, two large-scale amplifiers, a squaring block and a multiplier into the amplitude and frequency of the spectral components of the vibration spectrum at an operating frequency of rotation, and the defect size of the monitored bearing is calculated from them. 2 Il.

Description

The invention relates to a measurement technique, in particular, to devices for diagnosing defects in rolling bearings.

The purpose of the invention is to improve the accuracy of determining bearing defects.

Fig. 1 shows a functional diagram of a device for the diagnosis of rolling bearings; Fig. 2 shows the algorithm for the operation of the defect calculation unit and the following notation is adopted: S is the magnitude of the defect; WITH; - information frequency; А (ОЗ;) vibration signal amplitude at the information frequency CO; ; G; - the weighting factor corresponding to the frequency of CO; L value j-ro threshold; I - proportionality coefficient; Ohm is the frequency with which the defect calculator begins to enter a spectrum.

The device contains a vibration sensor 2 mounted on a controlled rolling bearing 1, a test stand. 3, the input of which is connected to the power supply unit 4 through a switch 5, a narrow-band filter 6, whose input

with

00 SE 0

through the amplifier 7 is connected to the output of the vibration sensor 2, and the output is connected to the second input of the multiplier 8, the output of which is connected to the first input of the defect calculation unit 9, the output of which is connected to the inductor 10. The device also includes a series-connected frequency meter 11, the input of which is connected to the test stand 3, divider 1 and the first large-scale amplifier 13, the output of which is connected to the second input of the defect calculation unit 9, and, in addition, connected in series to the square building 1 whose input is connected to the output row divider 12 and a second masshtany amplifier 15, whose output of the connections with the first input of the multiplier 8.

To eliminate the influence of the natural frequencies of the oscillatory system, the monitored bearing - the test bench narrow-band filter is tuned to the oscillatory preresonance frequency, at which the transfer function of the oscillatory system is equal to unity.

The device works as follows.

A piezoelectronic vibration sensor 2 is fixed on the controlled bearing 1. The bearing 1 is mounted on the output shaft of the test bench 3, is loaded with the necessary force, and is rotated at a constant predetermined frequency Cop by connecting the stand electric drive to the power supply unit 4 via switch 5. Then the test bench is disconnected 3 from the power supply unit k with switch 5, creating a coasting mode. In the process of reducing the speed of rotation of the bearing 1, the speed of movement of its elements decreases, the frequencies of the disturbing forces acting in the bearing 1 decrease, and the spectrum components shift to lower frequencies. The displacement of the vibration spectrum components allows them to be extracted at a constant frequency that is outside the range of the natural frequencies of the oscillatory system of a monitored bearing - a sensing stand, in the process of successive coincidence of the frequencies of the spectral components with a constant frequency of filter 6

15

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amplitude vibration spectrum of the bearing 1.

The signal from the vibration sensor 2 through the amplifier 7 is fed to the input of the narrow-band filter 6. Since the signal amplitude at the information frequencies decreases non-linearly as the rotation frequency decreases, because of the decrease in the spectrum of the spectrum being shot (due to the decrease in the signal-to-noise ratio), it is advisable choose the tuning frequency of the band-pass filter 6 as close as possible to the beginning of the resonant zone of the oscillatory system. The controlled bearing - test bench in the frequency response area of the system where its transmission coefficient is close to 1. Output signal The narrowband filter 6 is fed to the second input of the multiplier. At the same time, a signal proportional to the frequency of rotation of the bearing 1, taken from the output of the test bench 3, is fed to the input of frequency 25 of measure 11. The amplitude of the analog signal at the output of frequency meter 11 corresponds to the instantaneous frequency of rotation of the COM of the bearing 1. As the overrun process measures the instantaneous frequency of rotation 03 and the amplitude spectrum enters the defect calculation unit 9 through a narrow-band filter 6 tuned to

20

thirty

five

0

constant frequency pass CO

;

It is necessary to align the amplitude of each spectral component transmitted through narrowband filter 6 and the frequency of this spectral component to their values at the operating rotation speed.

The determination of the frequency of vibration disturbances from the errors of the bearing elements is made according to the formula

five

WITH;

CO-W

F

WITH

m

(one)

0

where CO, is the frequency of the i-th spectral component at the operating frequency of rotation of the bearing Cp;

passband narrowband filter; 00M - instantaneous frequency

bearing rotation. Ll the calculation of the disturbance frequency serves as a divider 12, the output signal of which will be U CO, and the first large-scale amplifier 13, which amplifies the input signal V

by a constant value equal to Wp tOq, / G3p and Sof-set. At the output of the first large-scale amplifier 13, we have the frequency components of the vibration spectrum of the bearing 1, corresponding to the operating frequency of rotation cp of the bearing. The output signal of the amplifier is fed to the second input of the unit 9 for calculating defects in monitored bearings.

The amplitudes of the vibration accelerations of the spectral components of the bearing vibration at a constant rotational speed are calculated by the formula

X (CO;) X (“;)“ 2pW (CD;), (2)

where X (CO () is the vibration acceleration measured at the frequency CJj at a constant operating frequency of the bearing ((Cx) 1,) is the vibration displacement;

SOR- working frequency of rotation

 -Bearing;

W () is the transfer function of an oscillatory system, a monitored bearing, and a measuring stand. In the process of running out of the controlled bearing 1, the vibration acceleration of the vibration sensor 2 is measured, which can be summarized as follows

Х &(СО;) Х (СО;) «Ч (сОф), (3)

where Xg (W;) is the vibration acceleration measured at the frequency CO; in run out mode.

 From the given expressions (2) and (3), it can be seen that the coefficient of conversion of the values obtained on coasting at a constant filter bandwidth, at which W (cOq) 1 to values corresponding to an ideal oscillatory system (with a unit W (CO) 1 transfer function), at a constant frequency of rotation

to .SH, nd, ".

X6 (CO,) COW

Thus, in order to restore the values of the perturbations of the spectrum of the ibration that passed through the narrow-band filter, it is necessary to produce

The device is equipped with a meter and a power supply, a 35-gauge vibration filter of the connections and indi-ation is determined, the scale-but-connecting square of the device is multiplied by the square of the multiplier filter, and the inputs are calculated smart multiply frequency move

multiplication by the conversion factor K., 55. divider.

For this, a squaring block is entered into the device, at the output of which a signal V will be generated and a second large-scale amplifier 15 generating the input signal by the value of () / COP - is specified). From the output of the second large-scale amplifier 15 signal equal to K,

U enters the first input of the multiplier 8, in which the multiplication of the output signal of the narrow-band filter 6 by the coefficient K

The corrected values of the amplitude of the TRD are transmitted to the first input of the unit 9 for calculating bearing defects. In block 9, the calculation of bearing defects on the basis of the recovered spectrum corresponding to the ideal oscillatory system of the monitored bearing - test bench 1 at the operating rotation frequency of the hem, using known diagnostic algorithms i (formula (l), figure 2)

25, the defects of the bearing to be checked are determined.

The result of the bearing diagnosis is displayed on the indicator 10.

0

0

Formula Invention A device for diagnostics of under-: rolling bearings, containing a test bench connected to the frequency and, through a switch, to the power supply units. 5 vibration sensors connected in series, an amplifier and a narrow-band filter, as well as a series of defect calculation unit and an indicator different from the one so that, in order to improve the accuracy of detecting bearing defects-1 ka, the serially connected divider and the first large-scale amplifier, the series-connected air unit, are introduced into the device lead b1 square, second scale amplifier, and multiplier, the output of the narrow band filter is connected to the second multiplier input, the output of the divider is connected to the input of the squaring block, and the first and second inputs of the defect calculator are connected to the inputs of the multiplier and the first scale -t multiplier, respectively, the output of the frequency meter is connected to the input

five

0

Lijli

eleven

Editor M. Vasiliev

Compiled by V. Rodimy Tehred M. Morgental

1

( Start

end

ig. 2

Proofreader A. Obruchar

Claims (1)

I FORMULA A rolling bearing device containing a test bench connected to the frequency with a measure and through a switch to the blocks. · 'Power supply connected in series? ¹ vibration sensor, amplifier and a narrow-band filter, as well as a series-connected defect calculation unit and an indicator, distinguishing) in that, in order to improve the accuracy of youth defective bearings, a series-connected divider and a first) scale amplifier are introduced into the device, series-connected building block in ·. . ⁵ square, the second large-scale amplifier <and the multiplier, and the narrowband output ·. · Which filter is connected to the second input? the house of the multiplier, the output of the divider is connected to the input of the squaring unit, and the first and second inputs of the defect calculation unit are connected to [the inputs of the multiplier and the first scale * multiplier, respectively; the frequency counter is connected to the input