SU783621A1 - Apparatus for diagnosis of cyclic mechanisms - Google Patents

Description

(54) DEVICE FOR DIAGNOSTIC CYCLIC

one

This invention relates to the diagnosis of cyclic mechanisms by their vibration parameters.

A device for diagnosing mechanisms is known in which a band-pass filter tuned to the 5th harmonic 1 of vibroacoustic 1 | Q signal of the mechanism, and multiplier 1 is used to correct the results depending on the speed mode of the mechanism.

The disadvantage of such a device is that it does not allow the mechanism to be diagnosed based on the time separation of the acoustic signals of various kinematic pairs.

The closest to the invention in terms of technical capability is a device for diagnosing cyclic mechanisms on the vibrations of the body, co-oscillators connected in series to 20 transducers, a matching unit, a control path including a programmed control unit connected to its input and output of a matching 2S unit , extremum extraction unit associated with the input to the input of the synchronous generator and the recognition path, including serially connected switching unit, filter unit and 30 MECHANISMS

the display unit, and controlled by the signal / control path 2T.

A disadvantage of this device is that the start of the synchro-generator is performed once per cycle of the mechanism's operation with a signal. The start of the cycle comes from the extremum extraction unit. After starting, the synchro-generator generates a sequence of gating pulses, the parameters of which the duration and time of occurrence are rigidly fixed by the internal structure of the synchro-generator. When the revolutions change, this leads to a systematic phase error Qi of gating the acoustic signals.

. rL.100%, b ha

where n is the speed at which diagnosis of PC is made, at which the sync generator was tuned.

This error can reach 10% or more. In addition, the reliability of the results of this device is low due to the influence of random noise that coincides with the cycle of the mechanism, for example, electrical pickups, load fluctuations, etc. The aim of the invention is to improve the accuracy and reliability of diagnostic results by correcting the parameters of strobe pulses depending on the speed mode of the mechanism while simultaneously averaging the result of recognizing a given number of randomly selected cycles. The goal is achieved by the fact that the synchronous generator is in the form of serially connected bandpass: a filter tuned to the Kth harmonic, a vibro-acoustic signal of the mechanism, the frequency of which is proportional to the speed mode of the frequency multiplier and the strobator, the input of the bandpass filter is connected to the xx of the unit the extremum of the mind and the control path, the output of the multiplier and the output of the extremum of the extremum unit are combined with the inputs of the control unit of the hydrojro control, the output of which is connected to the control input of the strobe device, and the output of the latter is the output of the synchro-generator and the control path, and the recognition path is equipped with series-connected between the blocks of filters and indication of the blocks of measuring transducers and averaging. FIG. 1 H3o6pa i ei-: a diagram of the proposed device; in fig. 2 and 3 are temporary diagrams of his work at the normal and low angular velocity of the mechanism. The device contains a vibration transducer 1, install -D on the body of the diagnosed mechanism, I agree on unit 2, the output of which is connected to the inputs of the control path 3 to the recognition path 4. The control path 3 consists of an extremum extraction unit 5, a software control unit b and a synchronous generator 7 in which a bandpass filter 8, a frequency multiplier 9 and a strobator 10 are connected in series. The outputs of the extremum extraction unit 5 and the multiplier 9 are connected to the inputs of the program control unit 6 The output of which is connected to the control input of the strobator 10, and the output of the latter is the output of the synchronizing generator 7 and the control path 3. Straw pulses at the output of the control path 3 control the operation of the recognition path 4, in which the switch 11, the filter unit 12, the transducer block 13, the averaging block 14 and the display unit 15 are connected in series. The device works as follows. The vibrations of the mechanism by means of the vibrating converter 1 are converted into an electrical signal and are fed through the matching unit 2 to the input of the control path 3 and the recognition path 4 (ordinate 2). In the control path 3, the signal is fed to the inputs of the extremum extraction unit 5 and the synchronous generator 7, the extrusion extraction unit 5 extracts the maximum vibration signal corresponding to the starting turn of the mechanism and generates a pulse arriving at the first input of the control block b (Fig. 2f 3, ordinate 6) . In the synchroheparate 7, the signal enters the input of the bandpass filter 8, which extracts the Kth harmonic of the vibroacoustic signal of the mechanism, which arrives at frequency 9 with multiplication factor m (ordinates 8.9). The magnitude of the product, K & T, determines the number of quat. By which the angle of sight of the shaft of the mechanism is divided. And the magnitude of a single quantum is determined from the ratio of D.G. For example, when K is 3, m 4., the number of quanta into which it is divided. one turn of the shaft of the mechanism is equal to 12, and the quantum value. By the appropriate choice of the product Kt, the quantum value q can be made sufficiently small. The output signal from the multiplier 9 is fed to the synchronization input of the strobator 10 and to the second input of the program control unit 6. If the time interval between pulses arriving at the inputs of the control unit B of the program 41.1 is less than some predetermined value t, which determines the phase error of the device, then an output appears at its output enabling the operation of the strobator 10 according to the synchronization signal received from the output of the multiplier 9 "At the same time, the beginning and end of the strobe pulses at the input of the strobator 10 coincides with the corresponding pulses at the output of the multiplier 9 a. The strobe pulses from the output of the generator 7 and the control path 3 control the operation of mmutatora tract 11 in the discrimination 4 (ordinate 10) which connects the signal output device 2 lean agree to one of the filter unit 12 filters. The output signal of this filter is measured by the corresponding converter in the block 13 of the measuring converters and is fed to the averaging block 14, in which the recognition results of the number of randomly selected cycles of the mechanism specified in block 6 of the program control are averaged. The results of the diagnosis are displayed on the information board of the display unit 15. When the speed of the mechanism changes, for example, when its angular velocity decreases, when the duration of the working cycle increases, the frequency of the synchronizing pulses at the output of the multiplier 9 and the frequency of the pulses decrease, corresponding to the beginning of the cycle at the output of the extremum extraction unit 5, as a result of which and the duration of the strobe pulses at the output of the strobator 10 with respect to the pulses of the collision of the kinematic pairs of the diagnosed mechanism does not change.

Thus, the implementation of the synchronous generator in the form of a serially connected bandpass filter, multiplier and strobator eliminated the error associated with changes in the speed mode of the mechanism, and the selection of 41 recognition blocks randomly by signals from the program control unit, whose inputs are connected to the outputs of the extremum selection unit and intelligent and averaging the results of recognition of a given number of randomly selected cycles reduces the recognition error associated with the influence of the case interference and increase the reliability of diagnostic results.

Claims (2)

1. Karaseva V.A. Vibration diagnostics of gas turbine engines, N., Mashinostroenie, 1978, p. 127. five 2. USSR author's certificate number 429288, cl. G 01 H 1/09, 1972 (prototype) fuz.