SU1380805A1 - Method of tuning vibration machine with piecewise linear characteristics to resonance vibrations - Google Patents

Abstract

The invention relates to a vibration technique and can be used in various sectors of the national economy to tune vibratory machines for resonant vibrations. The aim of the invention is to increase the technological stability of the vibrator. For the implementation of the proposed method, the stiffness coefficients of the main and additional elastic couplings and the amplitude of the harmonic excitation are determined from the tuning conditions of the vibrator with the piecewise linear characteristic of the elastic couplings to the main nonlinear resonance. Then, the harmonic excitation frequency is gradually increased, and the vibration amplitude and frequency of the vibrator are measured using a vibration acceleration sensor, an oscilloscope, and a frequency meter. Then the frequency of the harmonic excitation is gradually reduced and the frequency of the reverse jump from nonresonant oscillations resonance and amplitude of vibration accelerations X. nonresonant oscillations at the frequency of the reverse jump. Along with harmonic excitation, the vibromachine (Or is affected by an additional garm with a power of frequency W “Jy with“ / 1d) ki with an amplitude of R. (0.3–0.45) wX,: 5 or c. 5 (L from 00 o 00 o SP

Description

The invention relates to a vibration technique and can be used in various sectors of a national household to tune vibratory machines to resonant vibrations.

The aim of the invention is to increase the technological stability of the operation of the vibratory machine.

Figure 1 shows an example implementation of the method; FIG. 2 is a graph of the amplitude-frequency characteristic (AFC) of the vibration accelerations of the vibrator with a known tuning method; in FIG. 3, the frequency response of the vibration accelerations of the vibrator when implementing the proposed method of tuning; figure 4 is a diagram of the stability margin of the resonant vibrations of the vibrating machine in the prototype; Figure 5 is the same when implementing the proposed setup method.

The method can be implemented in a vibratory machine consisting of a working

body 1, installed on the main elastic connections x 2 with total stiffness K, for example on flat springs, one end of which is rigidly fixed on base 3, and the second is rigidly connected to working body I. On base 3, with a clearance D relative to working body 1, additional elastic connections 4 with a total stiffness K. On the working body 1, vibration exciter 5 is fixed, for example, electrodynamic, connected through an amplifier 6 to a generator of 7 multi-frequency voltage. To register the amplitude of the vibration accelerations and the oscillation frequency of the working body, a sensor 8 of the vibration accelerations is attached to it, connected via a second amplifier 9 to an oscilloscope 10 and a frequency meter 11.

The method is implemented in the following manner.

Out of equations

i + d id-, ry

L f - (

Kll2K.

k 1

7

P

A

-Af

iK (

mu) --- K arccos.

 US -A I

1 „DG + d

- -yK arccos --- - --- D., K2 + 2K,. JN (-P-A - A - d);

VL2

I (K - mup) + JU K JA

K K 4- (K „- K) arccos

 K 2 L

de m is the mass of the working body of the vibrator;

K is the operating frequency of harmonic excitation;

K is the total stiffness coefficient of the main elastic bonds (elements);

K is the total stiffness coefficient of the additional elastic bonds;

i is the size of the gap between the working body and additional elastic connections; d is the value of the constant mixing of the center of oscillations relative to the position of static equilibrium; And - the amplitude of the first harmonic in

vibration spectrum; JM - co: damping factor;

iK (1.04.

.1,1) muJ

one

.

40

Р - amplitude of harmonic excitation; stiffness coefficients are determined

TO

and To the main and additional elastic connections and the amplitude of the harmonic excitation. In the vibratory machine, the necessary values of the stiffnesses of the main and additional elastic connections are established, which in the case of, for example, the use of flat springs, are determined by the length of the spring. When using elastic connections of another design (twisted springs, torsion bar, etc.), the necessary values of the stiffnesses are established by known methods. The amplitude P of the harmonic excitation is established by applying the harmonic voltage of a given amplitude from the generator 7 of the polyfrequency voltage through efforts

6, an electrodynamic vibration exciter 5. The dependence of the amplitude P of the harmonic excitation on the magnitude of the amplitude of the harmonic voltage of the generator 7 is determined by the passport data of the generator 7, the amplifier 6 and the vibration exciter 5 or by their preliminary calibration. Then, the harmonic voltage frequency at the generator output 7 and, accordingly, the harmonic excitation frequency during the vibration exciter 5 are smoothly increased. Simultaneously, using the sensor 8, vibration accelerator, oscilloscope 10 and frequency meter 11 measure the amplitude of the vibrator and determine the time of the MSR stall vibrator vibrations at which there is an abrupt decrease in the oscillation amplitude of the vibrator (figure 2). After determining the frequency (breaking oscillations, the harmonic excitation frequency is smoothly reduced and the frequency u) j is determined in a similar way, the reverse vibration oscillator shock at which the vibration amplitude of the vibrator increases abruptly due to the transition from nonresonant to resonant oscillations. At the same time, the amplitude of the vibration accelerations X, corresponding to the non-resonant vibrations of the vibratory machine on

the frequency of the reverse jump and. Determining the frequency of u) r “, W vibration acceleration

wed

si

and amplitude

ck install

the required value of the working frequency i) p harmonic excitation and excite the resonant vibrations of the vibrator for what with the help of 1 (with the vibrator 5, the vibrators are influenced by an additional harmonic force, the frequency and amplitude of which are determined from the conditions

m

 Wn,, P Yu, p

P (0.3-0.43) tX h

An additional harmonic force is obtained by supplying an additional harmonic voltage with a frequency of 6J and amplitude to an electrodynamic vibro-Rudital 5 from generator 7, ensuring the excitation of the power PC-. The impact on the vibrating machine by an additional harmonic force leads to a shift of the frequency of the reverse jump to a higher

ten

f5

-, e 2Q -25

thirty

35

40

45

50

kih frequencies compared with a purely harmonic excitation (Fig.2, 3). In this connection, the frequency range is reduced, in which, along with the operating resonant mode, there are non-resonant oscillations. The impact on the vibrator with additional harmonic force also provides an increase in the stability margin of resonant oscillations (figure 5) as compared to purely harmonic excitation (figure 4).

The implementation of the method provides an increase in the technological stability of the operation of the vibratory machine, which consists in stabilizing the output of the vibratory machine to the resonant mode during its acceleration and in increasing the stability of the operating mode to external disturbances.

Claims (1)

Invention Formula The tuning method for resonant vibrations of a vibrator with a piecewise linear characteristic of elastic connections, which consists in the fact that the elastic connections perform a predetermined stiffness and with a certain deformation coefficient, establish the main ones without a gap, and the additional ones with a certain gap between them and the operating body machine and apply a disturbing force of a certain amplitude and frequency, which is different from the fact that, in order to increase the technological stability of the vibrator, it is additionally affected th harmonic loi, the amplitude and frequency of which is determined from the conditions i) l | 1 G (0.3-0.5) tX,; s where P is the amplitude of the additional harmonic force; frequency of additional gartmonic force; weight of machine tool us; vibration amplitude at the frequency of the reverse jump to swans; frequency of the reverse jump of oscillations; p is the working frequency of harmonic excitation;  - the frequency of failure of vibrator vibrations. U) m X  ci12 sosk 1JS W 2JO COfl Bc / (C Figg, 1 TO 0 1.2 4 4ff iff 2flaf. u, 3. FIG. five. (