RU1793266C - Mechanical vibration recorder - Google Patents

Abstract

The invention relates to measuring technique and can be used to identify sources of vibration of a structure. The device contains three vibration sensors 1-3, a three-input threshold device 4, a recording device 5, an N-kayalny synchronization circuit, including N frequency sensors 6 ... (1 + 5), N frequency dividers (N + 1 + 5) .. . (2 + 5), N pulse shapers (2N + 1 + 5) ... (3N + 5), where N is the number of considered structural details and, accordingly, the number of frequency sensors, frequency dividers and pulse shapers, i is the current number, respectively, of the structural part, frequency sensor, frequency divider, pulse shaper, i 1,2,3 ... N. 2 ill. k / 1C

Description

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CJ hO Os

about

The invention relates to measuring equipment and can be used to identify vibration sources of a structure, for example, a helicopter, an engine,

A device is known that comprises a vibration sensor and a threshold circuit that provides a signal for exceeding a predetermined vibration level, a Vibration frequency divider with an appropriately selected division coefficient, and an output device, optical or acoustic. These devices allow the frequency of flashes or sound signals to assess the vibration frequency of structures and the source that caused the vibration. °

The disadvantage of these devices is the poor quality of vibration control and n6 - sufficient noise immunity.,

The closest in technical essence to the claimed invention is a device containing a vibration sensor, a rotation frequency sensor, a synchronization circuit consisting of a pulse shaper, e The disadvantage of this device is

no possibility of revealing a series

25

sources of vibration, determination of the parameters of only one fundamental tone and its harmony; :: d ;;;; v- v; -; -; ..: ..V

The aim of the invention is the identification of vibration sources due to the synchronous registration of continuous components of the vibration process against the background of marks following the frequency, a multiple of the rotation frequency or the vibration frequency of parts controlled

DESIGNS. : h, 1. : to 5

This goal is achieved in that the device, including the vibration sensor, the frequency sensor, the transmitter, contains the second and third vibration sensors, the outputs of which are connected respectively to the first, second and third information input of the recording device and, respectively, to the first, second and third the input of a three-input threshold device, the output of which is 45 keys to the start input of the recording device, as well as the N-channel synchronization circuit containing N channels from series-connected x frequency sensor, frequency divider, pulse shaper 50, the outputs of N pulse shapers are connected respectively to the following N information inputs of the recording device.

The proposed device for recording 55 mechanical vibrations has significant differences in comparison with the known technical solutions, since it is the combination of distinctive features and their interconnection between themselves and from 0 5

0

5

0

5

0 5 0

5

by the known features inherent in the prototype, it is possible to identify a vibration source due to the synchronous registration of continuous components of the vibration process against the background of marks following with a frequency, a multiple of the rotation frequency or the oscillation frequency of the parts of the controlled structure.

In FIG. 1 is a structural diagram of the proposed device; Fig. 2 is a recording format of components of a vibration process and part marks.

The device contains three vibration sensors 1-3, the outputs of which are connected respectively to the first, second and third input of the three-input threshold device 4 and, respectively, to the first, second and third information input of the recording device 5, the M-channel synchronization circuit, including N frequency sensors 6 ... (1 + 5), N frequency dividers 7 {N + 1 + 5) ... (2N + 5), N pulse shapers 8 (2N + 1 + 5) .., (3N + 5 ), the outputs of which are connected respectively to the following N information inputs of the recording device 5, g de N is the number of considered structural parts and, accordingly, the number of frequency sensors, frequency dividers and pulse shapers, and I Current number, respectively, of the structural part, frequency sensor, frequency splitter, pulse shaper i

1,2,3 ... N.r :: - vV :: V ;;;; ;;. :.

The device operates as follows. . /.- -; -;

The mechanical vibrations of the structure under control are converted into a proportional electrical or mechanical signal corresponding to structural vibrations in three axes using three vibration sensors 1-3. The outputs of the vibration sensors are connected to a three-input threshold device 4 and three information inputs of the recording device 5, respectively. If the amplitude of oscillations in any of the three axes is exceeded above the set level, the threshold device 4 generates a start signal for the recording device 5, which starts recording the three components of the vibrating process of the structure against the background of the marks. The frequencies of rotation or vibrations of the structural parts produced by the frequency sensors 6 ... (N + 5) are divided by the respective dividers (N + .1 + 5) ... (2N + 5) with appropriately selected division factors Ki. The output signals of the dividers (N + 1 + 5) ... (2N + 5) via pulse shapers (2N + 1 + 5) .... (3N + 5) are converted to the form required for registration, are fed to other information inputs of the recording device 5 and are recorded in the form of m 5 currents. The span of recording part marks is set so as to eliminate or reduce the shadowing of the recording of components of the vibration process, as shown in Fig. 2. Determination of the ith part that caused the vibration of the structure is carried out by counting the number of MI periods of vibrational vibrations recorded during the period that each of the i marks (i 1 .... N) followed by pairwise comparison of MI with K If MI coincides with KJ the index will indicate a part DI rotating or oscillating with frequency FI and causing vibration of the structure at this frequency ...

EcnnMIIM (M | -Kt) 1, ... Nr

TpiN0Ki i, l Di. . The minimum value of K | and $ conditions are selected to achieve the required resolution, determined by the minimum frequency multiplicity Sm of vibration frequencies or oscillations of the parts of the controlled structure

 ,, L

Sm mln

where Gde1 1,2, ... M,

j N-i + 1: i J

I -

-i.-i +, b,

and

TO

, FJ -frequency of rotation or oscillation of the 1st j-th part of the controlled structure. Recognition Condition

min (Sm -l) V A I OR

m in terms of resolution, carrier pulling speed, the number of information inputs, for example, a K12-51 type light-beam oscilloscope,

Vibration sensors - any design that meets the requirements for accuracy, sensitivity and the range of operating frequencies, for example, MP-95.

Speed sensors can be

0 full-time, for example D1M, D2M, or newly installed.

Frequency dividers are constructed taking into account the conversion coefficient of the frequency sensor itself, so if a sensor is used

5 D1M, D2M, it must be taken into account that the frequency of their output voltage is 2 times the frequency of rotation of the sensor shaft. It is also necessary to take into account the ratio of rotational frequencies of the controlled part and the sensor shaft.

0 For example, receiving marks following with a period equal to two turns of the MI-8 rotor.

 1. The gear ratio from the input shaft of the gearbox VR-8A to the rotor

5 Sqv-nv 0.016; s.

2. The gear ratio from the input

gearbox shafts VR-8A to the shaft of the KVvdo sensor 0.1984; . ...: -

: 3.- The frequency of the output voltage of the rotation sensor is td. To 2fo6.v, where Tob.v is the rotational speed of the sensor shaft.

4. The period of repetition of the marks of the rotor is 2, W 2. We obtain the coefficient of Kn. in dividing the frequency of the voltage issued by the rotor speed sensor 5 to obtain the marks that follow with a period equal to two revolutions of the rotor

Prince W-ffl.o W-2-fo6.B

 2

w.KB.B.-fl.o., 2.2.0.1984 Qu.v.-present .0.016

D1

(Sm 1) V Al

 1

(Sm 1) V (Sm-1) -V

 1

where AI is the resolution of the information carrier;

i V is the speed of the carrier. The remaining Ki Kmin are selected from the condition of Uniquely identifying labels by their repetition period. Minimum media speed

j Vmln Fmax A I,

r & e Fmax is the maximum frequency of rotation of the vibrations of the part, i.e. ; Fmax -MAX {F;}.

The recording device can be any one that meets the requirements of Prin.Kn.v 50, we get an error - 0.008064 rel. By increasing W, we can reduce the error associated with rounding the resulting fractional Kn.v., and at N 20 we get the required Kn.v - 496, i.e., with absolute precision. To obtain marks following the rotational speed of the tail rotor or shaft

tail rotor, you can use the same voltage frequency output by the rotor speed sensor, but taking into account the gear ratio of the HB shaft or the sensor shaft of the rotor to the tail rotor shaft or the tail rotor itself. The connection between the HB, the drive shaft and the tail rotor is rigid, thus, using this fact, it is possible to obtain marks with a repetition period that is a multiple of the rotational speed and these

parts, as well as others, such as the main fan, using only one frequency sensor.

Directly divisors with a calculated division coefficient are constructed on the basis of digital counters with a fixed or programmable division coefficient, for example, performed according to the technology of KMO.P 561IE11, TTL 155IE7, 155IE6, 155IE9 or 555IE6, 555IE7. Any counters will do, i.e. all commercially available counters have a maximum counting frequency, significantly exceeding the speed or oscillation of parts actually existing or developed in the future. A pulse shaper is required between the frequency sensor and the direct divider, which will generate pulses of the required amplitude from a sinusoidal voltage, for example, on the basis of an amplitude comparator 554 SAZ. If it is necessary to increase the division coefficient to reduce the rounding error, a half-wave rectification circuit for alternating voltage output by the sensor can be used. You can also use the frequency multiplication scheme, for example, based on logic elements. Additions. A multiplier is installed between the output of the amplitude comparator and the input of the divider, in which the division coefficient is doubled. -., :: .-:,. l / v; ; . ; :

The pulse shaper is based on an amplitude comparator of the 554CAZ type. The value of the reference voltage is selected within the range of

Forumula and v

A device for recording mechanical vibrations, comprising a first vibration sensor and a pulse shaper, for example, in order to expand operational capabilities by identifying a vibration source, it is equipped with a second and third vibration sensor, a recorder , a three-input threshold block, the three inputs of which are connected respectively to the outputs of the first, second and third vibration sensors and 6 three inputs of the recorder, the fourth

to the maximum value of logical zero (log O) and the minimum value of .log. G at the output of the frequency divider. The amplitude of the positive impulse is regulated by P 1, the negative by P 3 and is determined by the required mark recording span and the relative position on the information carrier of the marks corresponding to the various parts taken into account when diagnosing vibration of the test structure. For example, the span of the recording marks of the rotor screw is set to be large compared with the span of recording the marks of the tail rotor, which simplifies the distinction of the marks of the screws not only by the repetition period, but by analogy: the rotor of a larger diameter than the steering rotor, respectively, and the scope of the record of marks of EB is larger than RV, etc.

The three-input threshold device is built on the basis of an amplitude comparator, for example, type 554CAZ, it has an open collector and emitter output, which allows them to be combined into a circuit OR, i.e. when triggered, either the first comparator, or the second, or third produces an output signal, which is then amplified to a level sufficient to turn on the recording device. Peak detectors are installed at the inputs of the amplitude comparators to prevent a command to turn on the recording device as a series of short pulses.

Achieving this goal allows reliable identification of the vibration source of the structure with minimal hardware costs.

the input of which is connected to the output of the three-input threshold block, an N-channel synchronization circuit, where N is the number of monitored vibration sources, each of the N channels of the synchronization circuit consists of series-connected frequency sensors of the monitored vibration source, frequency divider and pulse shaper, the outputs of each N channels of the synchronization circuit are connected respectively to each of the 4 + N inputs of the recorder, the first, second and third vibration sensors are located so that the axes of their sensitivity are orthogonal.