JP2601653B2 - Wave matching method of ultrasonic transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a wave matching method of an ultrasonic vibrator applied to an ultrasonic motor, ultrasonic processing, an atomizer, and the like.

<Prior art> A torsional vibrating element that generates a strain vibration in opposite phases in the circumferential direction and a longitudinal vibration element that generates a strain vibration in the thickness direction are laminated, and a metal block is disposed on the front and rear surfaces thereof, and these are bolted or the like. The one integrally joined is known as disclosed in JP-A-61-120677.

In this device, the torsional vibrating element generates rotation associated with torsional vibration and linear reciprocating motion in the axial direction by the longitudinal vibrating element on an end face, and generates an elliptical motion by the combination on the end face. It is intended for.

By the way, in such a configuration, the sound speed of the shear wave (torsional vibration wave) is lower than the sound speed of the longitudinal wave, and is only about 60%. Specifically, for a longitudinal wave of 5000 m / s, a transverse wave of 3000 m / s
It is about. Therefore, it is necessary to match the resonance frequency of the longitudinal vibration and the resonance frequency of the torsional vibration in order to take out the desired elliptical drive on the end face, and since the vibration modes are different, the front and rear metal blocks are different. However, in the case of a normal shape having the same diameter, elliptical motion cannot be actually extracted, and this is merely a proposal on a desk.

An object of the present invention is to provide a wave matching method of an ultrasonic vibrator that can manufacture an ultrasonic vibrator having such a structure by matching a longitudinal vibration wave and a torsional vibration wave.

<Means for Solving the Problems> According to the present invention, a torsional vibrating element that generates a strain vibration in opposite phases in the circumferential direction and a longitudinal vibrating element that generates a strain vibration in the thickness direction are stacked and disposed on the front and rear surfaces thereof. Each of the vibrating elements is sandwiched by a metal block and a combination of longitudinal vibration and torsional vibration causes an elliptical motion on the tip end surface.
The torsional vibration wave is adjusted by changing the cross-sectional area of the metal block, the longitudinal vibration wave is adjusted by setting the total length thereof, and the torsional vibration wave and the longitudinal vibration wave are matched.

<Operation> The inventor of the present invention has conducted various investigations and experiments on a vibrator having such a structure. As a result, the longitudinal vibration wave is greatly affected by the total length of the vibrator, while the torsional vibration wave is rotated. Since the effect of the inertial force is large, it has been found that the characteristics vary greatly with changes in the cross-sectional area.

The present invention uses these characteristics to adjust the overall length and cross-sectional area to make the apparent sound speed of the longitudinal vibration wave and the torsional vibration wave the same, and to match the resonance frequency of the vibration mode corresponding to each vibration wave. It is intended to be.

It is difficult in mass production to reliably match the resonance frequencies of the longitudinal vibration mode and the torsional vibration mode. Therefore, there is no problem even if there is a variation of about ± 10%, preferably within ± 5%. The vibration mode in which the longitudinal vibration wave and the torsional vibration wave overlap is such that when the longitudinal vibration wave is half-wave resonance (primary mode), the torsional vibration wave is one-wavelength resonance (secondary mode), and the longitudinal vibration wave is one-wavelength resonance (primary mode). In the case of the second mode, the torsional vibration wave has a combination of 1.5 wavelength resonance (third mode). In addition, there is a combination of a longitudinal vibration wave in the third mode and a torsional vibration wave in the fifth mode.

That is, the total length and the cross-sectional area may be determined based on the combination of the vibration modes.

An embodiment of the present invention will be described with reference to the accompanying drawings.

Referring to FIG. 1, 2a and 2b are torsional vibrating elements composed of two annular piezoelectric elements made of PZT or the like that are polarized in the circumferential direction and generate circumferentially distorted vibrations of opposite phases to each other, The longitudinal vibration elements 3a and 3b composed of two annular piezoelectric elements having thickness polarization directions different from each other are laminated on this.

Then, metal blocks 4 and 5 made of duralumin are arranged on both sides of the laminate, and a bolt 6 is inserted into the center of each member, and screws 6a and 6b at the upper and lower ends thereof are connected to the metal block 5 at the rear.
And the nuts 7 arranged at the front end of the metal block 4 are screwed together, and the vibrating elements 2a, 2b, 3a, 3b are clamped between the metal blocks 4, 5, and the ultrasonic vibrator 1.

In such a configuration, the metal block 4 has a reduced diameter portion 10 formed by coupling a front portion thereof to a small diameter portion 9 via a tapered surface 8, and the nut 7 has the same diameter as the small diameter portion 9. And

As a result, the length of the metal blocks 4 and 5 is determined to determine the overall length, and the diameter of the reduced diameter portion 10 of the metal block 4 is determined to adjust the cross-sectional area. By this adjustment, as shown in FIG. 1, when the longitudinal vibration waves driven by the longitudinal vibration elements 3a and 3b are at half-wave resonance (first-order mode), the torsional vibration waves driven by the torsional vibration elements 2a and 2b are One-wavelength resonance (secondary mode) is set. In addition, combinations of various modes can be realized as described above.

The metal block 4 also functions as a horn due to the reduced diameter portion 10, and a large amplitude is generated at the front end thereof as compared with the rear end of the metal block 5, as shown by the velocity distribution waveform.

In such a configuration, when an alternating voltage of a predetermined frequency is applied to the torsional vibrating elements 2a, 2b and the longitudinal vibrating elements 3a, 3b based on the above-described relationship, the rotational motion accompanying the torsional vibration and the longitudinal vibration , A motion is generated that combines the reciprocating linear motion. And the amplitude of torsional vibration and longitudinal vibration is the same,
When the phases are the same, a circular motion is performed, and when the amplitude and the phase are changed, an elliptical motion is performed. Furthermore, the rotation can be reversed.

Next, FIG. 2 shows another adjusting means of the cross-sectional area.
20 is formed. The cross-sectional area of the metal block 4 is adjusted by selecting the diameter of the neck portion 20.

FIG. 3 shows a vibration element 2 of a metal block 4, 5 having the same diameter formed with a screw hole at the center.
The bolts 30 are shortened so that the adjustment holes 31 are formed by using the screw holes of the metal block 4 in the one holding the a, 2b, 3a, 3b. Then, the cross-sectional area of the metal block 4 is reduced by the adjustment hole 31, and the adjustment can be performed.

<Effect of the Invention> As described above, the present invention adjusts the torsional vibration wave by changing the cross-sectional area of the metal block, and adjusts the longitudinal vibration wave by setting the total length thereof. Thus, there is an excellent effect that the elliptical motion can be effectively extracted from the end.

[Brief description of the drawings]

The accompanying drawings show an embodiment of the present invention, and FIG. 1 is a side view in which the lower half of an ultrasonic vibrator 1 showing one embodiment of a block cross-sectional area adjusting means is longitudinally cut. The velocity distribution waveform is also shown along the axial direction. FIG. 2 is a side view of the second embodiment, and FIG. 3 is a side view in which a lower half of the third embodiment is longitudinally cut. 1; ultrasonic vibrator, 2a, 2b; torsional vibrating element, 3a, 3b; longitudinal vibrating element, 4, 5; metal block, 10; reduced diameter portion, 20: reduced neck portion, 31; adjustment hole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Minoru Kurosawa 1-6-11 Susukino, Midori-ku, Yokohama-shi, Kanagawa Prefecture (72) Michiyuki Masuda 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi Japan Special Ceramics Co., Ltd. (56) References JP-A-60-148388 (JP, A) JP-A-62-152377 (JP, A) JP-A-62-247871 (JP, A)

Claims (1)

(57) [Claims] 1. A torsional vibrating element that generates a strain vibration in opposite phases in the circumferential direction and a longitudinal vibrating element that generates a strain vibration in the thickness direction are laminated, and each of the vibrating elements is sandwiched by metal blocks disposed on the front and rear surfaces thereof. Then, by combining the longitudinal vibration and the torsional vibration, an elliptical motion is generated on the tip surface.
Ultrasound characterized in that the torsional vibration wave is adjusted by changing the cross-sectional area of the metal block, the longitudinal vibration wave is adjusted by setting the total length thereof, and the torsional vibration wave and the longitudinal vibration wave are matched. A method for matching the wave of a vibrator.