SU1614855A1 - Method of exciting mechanical vibrations in magnetostrictive transducer - Google Patents

Abstract

The invention relates to ultrasound technology. The goal is to improve the usability of the magnetostrictive converter and to improve working conditions by reducing the power of spurious acoustic oscillations in the frequency range of the person’s greatest susceptibility to them. The method consists in applying to the magnetostrictive converter pulses of electric current, the duration of which is less than half the period of natural oscillations of this converter, and the frequency is less than the frequency of its own mechanical oscillations. The electric current pulses are fed with a constant phase shift relative to their own mechanical vibrations of the magnetostrictive converter. The frequency of the electric current pulses is changed according to a stochastic law in the range of 0≤F _n ≤F≤F _to * 98F, where F is the current value of the frequency of the electric current pulses, F _n is the lower frequency value of F, F _in is the upper frequency value of F, F - frequency of natural mechanical oscillations of a magnetostrictive converter. 2 Il.

Description

The invention relates to ultrasound technology, in particular, to methods for pulsed excitation of electromechanical transducers, and can be used to excite mechanical oscillations in magnetostrictive transducers (MRPs), for example, which are part of ultrasonic knives.

The purpose of the invention is to improve the usability of the converter and to improve working conditions by reducing moshes, - the effectiveness of the emitted oscillations of an ICP in the region of greatest susceptibility to them.

The method consists in applying to the magnetostrictive converter pulses of electric current, the duration of which is less than half the period of natural oscillations of this converter, and the frequency is less than the frequency of its own mechanical oscillations. Current pulses are supplied with a constant phase shift.

relative to natural mechanical oscillations of a magnetostrictive transducer. The frequency of the electric current pulses is changed according to the stochastic law in the range

where /

the current value of the frequency of the pulses of electric current; C is the lower value of the frequency /; 4 upper frequency value /; F - own mechanical frequency

fluctuations in SMEs.

FIG. 1 shows the spectrum of acoustic oscillations emitted by an MRF when mechanical oscillations are excited in it by a known method; in fig. 2 - the same, when the excitation of mechanical vibrations by the proposed method.

FIG. 1 and 2 accept the following designations; 1 - amplitude value

05 4

00

sd ate

excited mechanical oscillations in the SHSP at the resonance frequency; 2 - the amplitude of the emitted parasitic acoustic oscillations at the frequency of the exciting pulses of electric current (in this case, it was assumed that the frequency of the mechanical resonance of the MRF is three times the frequency of the exciting pulses of the electric current); 3 - the value of the amplitudes of the emitted parasitic acoustic collioparasitic acoustic oscillations at the frequency of the supplied electric pulses is blurred in the range from f to fg, i.e., beyond the range of frequencies to which a person exhibits the greatest susceptibility.

Since this frequency range is twice as wide as that of the human ear, with uniform emission of parasitic acoustic oscillations in the JJ range. T.- - .. ch1gg, -, .- and (gpp lurOIITLTOr Tt-.

emitted parasitic acoustically x kil .- ;; ;; 44, Hz radiated power banyi at frequencies of harmonics frequency 1 - - „„ e from O to ,,,,,,.

buzhdeni; 4 is the frequency range of acoustic oscillations to which a person is most susceptible; -5 is the amplitude value of 10 0 induced mechanical oscillations in an SME at the resonance frequency; 6 - the lower frequency of the excitation pulses e; electric current (fj; 7 - upper frequency of excitation pulses of electric current (f); 8 - frequency range of acoustic oscillations to which the person is most susceptible.

npii excitation of mechanical oscillations according to a known method (Fig. 1) s magnetostrictive transducer, for example, working with a resonant frequency .., -... g -. g., g 4n ir T-lT i LI Г piJ, - - j

at the frequencies of the greatest susceptibility of a person falls several times.

Claims (1)

Invention Formula  The method of exciting mechanical vibrations in a magnetostrictive transducer by applying electric current pulses to it, the duration of which is less than half the period of its own mechanical oscillations of the magnetostrictive transducer, and the frequency is less than the frequency of its own mechanical oscillations of the magnetostrictive transforming & that, in order to increase the convenience, for example, working with resonant. .... hectares of magnetostriction pre, oh kHz, impulses were given with a half- .III, improvement of working conditions This kHz is equal to the third subharmonic of the resonant frequency. At the same time, due to the final quality factor, part of the input power was re-emitted at the frequency of the supplied electric pulses, which led to unpleasant sensations of the operator, and consequently, a drop in the productivity of his labor. According to the invention, electric oscillations, whose frequency varies stochastically in the range from / 0 to kHz, are applied to the SMEs (Fig. 2), while the duration of the pulses does not exceed half the period of the own oscillations of the SRI of the SMEs and the phase shift between the population; With electric current pulses, the DASP oscillations in a mechapy resonance are maintained at a rate of 5, h, | m. The spectrum of the emitted radiation is l 1. forcing and improving working conditions by reducing the power of parasitic acoustic oscillations in the frequency range of the greatest susceptibility of a person to them, the electric current pulses fall with a constant phase shift relative to the intrinsic mechanical oscillations of the magnetostrictive converter, and the frequency of the electric current pulses changes stochastic law in the range Ze Ih : F, the current value of the pulse frequency of the electric current; r11 - ;;; more frequency value /; upper frequency f; - frequency of own mechanical coupling of a cag-constricting converter. parasitic acoustic oscillations at the frequency of the supplied electrical impulses are smeared in the range from f to fg, i.e., beyond the range of frequencies to which a person exhibits the greatest susceptibility. Since this frequency range is twice as wide as that of the human ear, with uniform emission of parasitic acoustic oscillations in the JJ range. T.- - .. ch1gg, -, .- and (gpp lurOIITLTOr Tt-.  ;; ;; 44, Hz radiated power Yu „e from O to ,,,,,,.  ;; ;; 44, Hz radiated power „e from O to ,,,,,,. } piJ, .. - j at the frequencies of the greatest susceptibility of a person falls several times. Invention Formula  The method of exciting mechanical vibrations in a magnetostrictive transducer by applying electric current pulses to it, the duration of which is less than half the period of its own mechanical oscillations of the magnetostrictive transducer, and the frequency is less than the frequency of its own mechanical oscillations of the magnetostrictive transforming & that, in order to increase the ease of use of the magnetostriction pre operation of the magnetostriction pre. forcing and improving working conditions by reducing the power of parasitic acoustic oscillations in the frequency range of the greatest susceptibility of a person to them, the electric current pulses fall with a constant phase shift relative to the intrinsic mechanical oscillations of the magnetostrictive converter, and the frequency of the electric current pulses changes stochastic law in the range Ze : F, the current value of the frequency of the pulses of electric current; r11 - ;;; more frequency value /; upper frequency f; - the frequency of the own mechanical coupling of the cag-ings converter. FIG. 7 FIG. 2