JP2001179179A - Ultrasonic vibrator transducer and composite vibration generating ultrasonic vibrator transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic vibrator transducer which can continuously, stably and completely match respective resonance frequencies even when a plurality of different resonance elements exist in one vibrator. SOLUTION: The ultrasonic vibrator transducer 6 is provided with a frequency variable means 13 for forcibly changing the resonance frequency of the vibrator transducer 6 by impressing the voltage offset in the phase angle at the same frequency as the frequency of the voltage to be impressed to a main piezoelectric elements 1 to at least a pair of remaining sub-piezoelectric elements 2 when the vibrator transducer is vibrated by impressing the driving voltage to >=1 pair of the main piezoelectric elements 1, by which the resonance frequencies of the vibrator transducers 6 are forcibly offset to the arbitrary frequencies and the stable vibration by automatic tracking is made possible. Consequently, if this vibrator transducer is applied to the case the plural vibrator transducers are driven at the same frequency as with, for example, an ultrasonic power synthesizer, the efficient and stable operation is realized by easily matching the frequencies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ultrasonic vibrator or a composite vibration generating ultrasonic vibrator used for performing various kinds of processing.

[0002]

2. Description of the Related Art Conventionally, in the field of ultrasonic machining requiring relatively large power, Langevin type vibrators which can easily obtain high output are often used as ultrasonic vibrators. The resonance frequency of this Langevin type vibrator is substantially determined by physical characteristics such as Young's modulus, density, and dimensions of components constituting the same, but shows a fairly sharp resonance. That is, since the electrical sharpness, so-called Q (Quality Factor), is very large, the impedance greatly changes near the resonance frequency, and the impedance and amplitude of the vibrator greatly change even if the driving frequency is slightly shifted. Therefore, in order to realize efficient ultrasonic vibration, the resonance frequency of the vibrator must be accurately and automatically tracked.

[0003] If the driving frequency is slightly different from the resonance frequency, there is a risk that a desired vibration amplitude cannot be obtained or an abnormal current flows to destroy the vibrator or the oscillation device. For this reason, a slight change in the resonance frequency due to a temperature change or a load change cannot be ignored, and a technology for always detecting the change in the resonance frequency of the vibrator and automatically and precisely tracking the frequency to drive is indispensable. Therefore, the oscillator feeds back the vibration state of the vibrator and controls the oscillation frequency in accordance with the phase change of the electric signal in the vibration state.
The "cked loop" method is widely used.

For example, when ultrasonic vibration is applied to a field such as plastic working of metal, a power of several kW or more is often required in a working portion. In such a case, a method is used in which the output powers of a large number of transducers are combined, taken out as a large power, and used.

As an example, FIG. 12 shows an ultrasonic power synthesizer 201. Exciting vibrators 203 are mounted on three surfaces of a power-combining vibrating body 202 having a cruciform shape each having a half-wave length (λ / 2), and a processing horn 20 is mounted on the remaining one surface.
In the case of the ultrasonic power combiner 201 equipped with 4, the combined ultrasonic power of the three excitation transducers 203 is obtained from the processing horn 204.

However, in this case, each of the excitation vibrators 2
If the electrical characteristics such as the resonance frequency of 03 do not match, it is difficult to obtain an efficient output. If a plurality of transducers having electrical characteristics such as resonance frequencies that do not match are coupled, some spurious responses appear due to the different resonance frequencies, and ideal automatic tracking cannot be performed. If used continuously in such a state, the required ultrasonic power cannot be obtained, or a load is applied only to a specific vibrator, which may damage the vibrator or destroy the oscillator. Such troubles occur.

In order to avoid such a phenomenon, in the final stage of manufacturing the vibrator, for example, a method has been adopted in which the dimensions of the vibrator are trimmed or the frequency is adjusted so as to match each other. In addition, it is very complicated, and in some cases, each resonance frequency may be shifted again due to aging, which is not perfect.

[0008] For the purpose of effective use of ultrasonic vibration, vibrators of various vibration modes have been proposed and put into practical use, and an axial vibration mode that vibrates in a direction coinciding with the axial direction existing before has been proposed. Of course, various types of vibrators utilizing a torsional vibration mode that vibrates in the direction of twisting about the axis, a flexural vibration mode in which a bending moment acts in a direction perpendicular to the axis, and the like have been proposed and used. The "axial vibration mode" referred to here is a longitudinal wave (compression wave), and the torsional vibration mode is a transverse wave (shear wave). The vibration propagation mechanism is completely different. Sound speeds are different. Further, the flexural vibration mode is also called a bending wave, and the speed of sound changes greatly depending on the shape of the vibrating body, and is different from the transverse wave of torsional vibration. λ =
The wavelength λ at the resonance frequency expressed by the formula of V / F (λ: wavelength, V: sound speed, F: resonance frequency) is completely different in each vibration mode. Therefore, when conditions such as load and temperature change between different vibration modes, the rate of change of the resonance frequency in each vibration mode also differs.

[0009] With the recent progress of industrial technology, as the attempts to use ultrasonic waves have become more active, there has been an unprecedented vibration mode, especially a composite vibration generating ultrasonic vibration which realizes a plurality of vibration modes with one vibrator. There is an increasing demand for realizing a vibrator, and attempts have been made to obtain a further improvement in performance by ultrasonic waves by drawing a two-dimensional or three-dimensional complicated vibration trajectory at the vibrator tip.

For example, torsional vibration (Totional) that vibrates in the torsional direction and axial vibration (Longitud) that vibrates in the axial direction.
In the case of a TL-type composite vibrator that realizes (inal) with one vibrator, the sound speed of each vibration mode is usually different, so that the resonance frequency is completely different between the axial vibration and the torsional vibration.

However, it is possible to make the resonance frequency of the torsional vibration coincide with the resonance frequency of the shaft vibration by designing the shape. Generally, the wavelength of torsional vibration is shorter than the wavelength of axial vibration, but the resonance frequency can be matched by modifying the shape and designing the vibrators so that the wavelengths have the least common multiple of each other.

In this case, the vibration trajectory at the vibrator tip can generate a helical vibration if the voltage phase for driving the axial vibration and the torsional vibration is the same. As an example, FIG. 13 shows a configuration of a TL composite vibrator 211 and a vibration distribution diagram thereof. At the design stage, the Langevin-type TL composite vibrator 211 in which the axial vibration piezoelectric element 214 and the torsional vibration piezoelectric element 215 are sandwiched between the front horn 212 and the rear horn 213 and fastened with the fastening bolts 216. Each of the piezoelectric elements 2
If a high-frequency voltage synchronized with the resonance frequency is applied to 14, 215, it becomes possible to simultaneously generate shaft vibration and torsional vibration.

At this time, when the amplitude is taken on the vertical axis, FIG.
3, the axial vibration is represented as an axial vibration distribution 217, and the torsional vibration is represented as a torsional vibration distribution 218.

However, it is very difficult to keep the resonance frequencies consistently stable in practical use. That is, the vibrator 21
The change rate of the resonance frequency that varies depending on the temperature change and the magnitude of the load, as well as the wear, re-grinding, or replacement of the tool mounted on the 4,215, is different depending on the vibration mode. The frequency differences are far apart.

Further, various attempts have been made to generate elliptical vibration using such a composite vibrator.

However, the elliptical vibration is obtained by driving different vibration modes in the first place at the same frequency and adjusting the phase thereof. As described above, it is very difficult to obtain the elliptical vibration stably for a long time. Difficult.

However, there has been an attempt to obtain a stable elliptical vibration by using automatic tracking even for a short time, and FIG. 14 shows an example of the basic configuration. The front horn 212 and the rear horn 213 sandwich the axial vibration piezoelectric element 214 and the flexural vibration piezoelectric elements 219 and 220, and tighten the fastening bolt 216.
Langevin-type BL (Bending-Longi)
A composite type vibrator 221 is formed. Here, the flexural vibration piezoelectric elements 219 and 220 are formed into a semi-annular shape by dividing a ring-shaped piezoelectric element in which two piezoelectric directions are opposed to each other into two.

The flexural vibration piezoelectric element 219 has a positive piezoelectric surface facing the positive side (indicated by → ←), and the flexural vibration piezoelectric element 220 has a negative piezoelectric direction facing the negative surface (←←). (Represented by →). When a driving voltage is applied to the common electrode, the other piezoelectric element 220 or 219 contracts in a cycle in which one piezoelectric element 219 or 220 expands, so that it is possible to easily generate flexural vibration, and The B-L type composite vibrator 221 is configured in combination with the vibration piezoelectric element 214. The shape of this vibrator is devised at the design stage to match the resonance frequencies of each other. If a high-frequency voltage synchronized with the resonance frequency is applied to each of the piezoelectric elements 219 and 220, the axial vibration and the flexural vibration can occur simultaneously. Can be generated.

Now, the output of the voltage controlled oscillator (VCO) 222 is amplified by the flexural vibration output amplifier circuit 223 and applied to the flexural vibration piezoelectric elements 219 and 220 via the flexural vibration speed detector 224.

Here, the phase difference between the applied voltage and current is detected by the flexural vibration speed detector 224, and the deviation from the resonance frequency is output as a frequency control voltage V1 and fed back to the voltage control oscillator 222, and the driving frequency If the resonance frequency deviates from the original resonance frequency, the difference appears in the frequency control voltage V1 and the oscillation frequency of the voltage controlled oscillator 222 is controlled to form a PLL type automatic tracking circuit that constantly oscillates stably at the resonance frequency. Makes it possible to continue stable vibration at the resonance frequency.

Next, if the output of the voltage controlled oscillator 222 is amplified by the shaft vibration output amplifying circuit 226 via the phase controller 225 and applied to the shaft vibration piezoelectric element 214, the shaft vibration is simultaneously generated. become. Here, the phase controller 22
If the phase is shifted by 5, the operation timings of the flexural vibration and the shaft vibration are also shifted in phase, and a vibration trajectory of a Lissajous waveform is generated. If the phase is shifted by 90 degrees, the tip of the vibrator is as shown in FIG. Trajectory S of the elliptical vibration is drawn.

However, this can be realized only when the resonance frequencies of the two vibration modes are completely the same. If at least one of them is slightly deviated from the resonance frequency, the vibration mode of the vibration mode deviated from the resonance frequency is deviated. The efficiency is extremely deteriorated, and only a small amplitude is obtained, which results in an almost linear vibration trajectory.

In the case of the circuit shown in FIG. 14 as an example, since the resonance frequency of the flexural vibration is always automatically tracked, it is possible to stably vibrate at the resonant frequency. It is only driven at a frequency.

Therefore, if the resonance frequency of the shaft vibration is shifted for some reason, stable elliptical vibration cannot be obtained. The Langevin type vibrator has a rather sharp resonance,
Since Q (Quality Factor) is very large, even if the resonance frequencies of the shaft vibration and the flexural vibration are matched at the design stage, the change rate of the resonance frequency is different when the conditions such as load and temperature change. As a result, the resonance frequency becomes completely different, and as a result, the relative phase and the relative amplitude are shifted, and the vibration mode cannot be properly controlled.

Therefore, ultrasonic elliptical vibration in the Langevin-type composite vibrator is in a state where only temporary experimental results have been obtained in the applied research stage.

In addition, a BT type composite vibration that realizes a bending vibration (Bending) vibrating in a direction perpendicular to the axis and a torsional vibration (Totional) vibrating in a direction torsion with respect to the axis with one vibrator. T that combines a child and three vibration modes
Although there are -BL type composite vibrators, etc., it is practically impossible to satisfy each resonance frequency and keep the same in each case for the same reason.

[0027]

As described above, in such a conventional technique, in a device for obtaining a large output by synthesizing a plurality of ultrasonic vibrators, the resonance frequencies of the respective vibrators can be easily made to match each other, and this can be continued. It is difficult to stabilize. In addition, since it is a conventional general control technique to detect the fluctuation of the resonance frequency inherent in the ultrasonic vibrator and drive at a frequency corresponding to the frequency, in the case of a composite vibration generating ultrasonic vibrator, Although it is possible to drive each oscillator separately by connecting it to the resonance frequency that fluctuates in each mode, there is no technology that actively controls the resonance frequency of the vibrator in real time. It is impossible to perform stable vibration control stably.

That is, when there are a plurality of different resonance elements in one vibrating body, it is physically impossible to continuously stabilize them even if the respective resonance frequencies are matched at the design stage. There has been a long-awaited need for a method of actively controlling the resonance frequency as a countermeasure.

Therefore, the present invention provides a vibrator by applying a signal having a different phase to a part of the piezoelectric element constituting the ultrasonic vibrator or connecting an impedance element to control the value. Ultrasonic frequency that can forcibly control the resonance frequency of each of the oscillators continuously and stably, even when there are a plurality of different resonance elements in one vibrator. It is an object to provide a vibrator and a composite vibration generating ultrasonic vibrator.

[0030]

According to a first aspect of the present invention, there is provided an ultrasonic vibrator comprising a combination of at least one main piezoelectric element and at least one sub-piezoelectric element. When a driving voltage is applied to the piezoelectric element to cause vibration, a voltage having a phase angle shifted by the same frequency as the voltage applied to the main piezoelectric element is applied to at least a pair of the sub piezoelectric elements. Frequency changing means for forcibly changing the resonance frequency of the slave.

That is, the resonance frequency of the ultrasonic vibrator can be forcibly controlled by applying a voltage having a phase angle shifted from that of the main piezoelectric element to the sub-piezoelectric element among a plurality of pairs of piezoelectric elements. The resonance frequency of the ultrasonic transducer is forcibly shifted to an arbitrary frequency by applying a voltage to the main piezoelectric element to vibrate, and applying a voltage to the sub-piezoelectric element at the same frequency with a phase angle shifted, and Stable vibration by automatic tracking becomes possible. As a result, even when a plurality of transducers are driven at the same frequency as in the case of an ultrasonic power synthesizer, by applying the present invention, the frequencies can be easily matched to achieve an efficient and stable operation, and The problem of change is gone.

According to a second aspect of the present invention, there is provided an ultrasonic vibrator comprising a combination of at least one pair of main piezoelectric elements and at least one pair of sub piezoelectric elements, wherein a driving voltage is applied to at least one pair of the main piezoelectric elements. When applying and vibrating, both ends of the remaining at least one pair of the sub-piezoelectric elements are short-circuited at the same frequency as the voltage applied to the main piezoelectric element and at a timing shifted in phase angle to force the resonance frequency of the vibrator. Frequency varying means for dynamically changing the frequency.

That is, the resonance frequency of the ultrasonic vibrator is forcibly set by short-circuiting the electromotive force generated at both ends of the sub-piezoelectric element at the timing of shifting the phase angle with respect to the main piezoelectric element among the plural pairs of piezoelectric elements. That can be controlled
A voltage is applied to one or more main piezoelectric elements to vibrate, and the remaining one or more sub piezoelectric elements are short-circuited at both ends of the sub piezoelectric element at the same frequency as the voltage applied to the main piezoelectric element and at a phase angle shifted. By doing so, the resonance frequency of the ultrasonic transducer is forcibly shifted to an arbitrary frequency, and stable vibration by automatic tracking becomes possible. As a result, even when a plurality of transducers are driven at the same frequency as in the case of an ultrasonic power synthesizer, by applying the present invention, the frequencies can be easily matched to achieve an efficient and stable operation, and The problem of change is gone.

According to a third aspect of the present invention, there is provided an ultrasonic vibrator in which at least one pair of main piezoelectric elements and at least one pair of sub piezoelectric elements are combined, a driving voltage is applied to at least one pair of the main piezoelectric elements. When applying and vibrating, there is provided frequency variable means for short-circuiting both ends of at least a pair of the remaining sub-piezoelectric elements with a coil and changing the inductance of the coil to forcibly change the resonance frequency of the vibrator. .

That is, of the plurality of pairs of piezoelectric elements, a coil is connected to both ends of the sub-piezoelectric element and the inductance thereof is changed so that the resonance frequency of the ultrasonic vibrator can be forcibly controlled. When a drive voltage is applied to one or more main piezoelectric elements to vibrate, a coil is connected to the remaining one or more sub piezoelectric elements, and both ends of the sub piezoelectric element are short-circuited to change the inductance of the coil. Thus, the resonance frequency of the ultrasonic vibrator is forcibly shifted, and stable vibration by automatic tracking becomes possible. As a result, even when a plurality of transducers are driven at the same frequency as in the case of an ultrasonic power synthesizer, by applying the present invention, the frequencies can be easily matched to achieve an efficient and stable operation, and The problem of change is gone.

The composite vibration generating ultrasonic vibrator according to the fourth aspect of the present invention is capable of simultaneously vibrating in different vibration modes of the main vibration mode and the sub vibration mode by combining a plurality of pairs of piezoelectric elements having different vibration modes. In a composite vibration generating ultrasonic vibrator in which a vibrator portion that vibrates in the sub-vibration mode is a combination of one or more main piezoelectric elements and one or more sub-piezoelectric elements, the piezoelectric vibrating in the main vibration mode A voltage whose phase angle is shifted at the same frequency as the voltage applied to the element is applied to the auxiliary piezoelectric element vibrating in the auxiliary vibration mode, and the resonance frequency of the auxiliary piezoelectric element vibrating in the auxiliary vibration mode is forcibly changed. Frequency varying means for causing the resonance frequency of the auxiliary vibration mode to always match the resonance frequency of the main vibration mode.

In the composite vibration generating ultrasonic vibrator according to the fifth aspect of the present invention, a plurality of pairs of piezoelectric elements having different vibration modes can be combined to vibrate simultaneously in the main vibration mode and the sub vibration mode. In a composite vibration generating ultrasonic vibrator in which a vibrator portion vibrating in the sub-vibration mode is a combination of one or more main piezoelectric elements and one or more sub-piezoelectric elements, the sub piezoelectric vibrating in the sub vibration mode The two ends of the element are short-circuited at the same frequency as the voltage applied to the piezoelectric element vibrating in the main vibration mode and at a timing shifted in phase angle to forcibly change the resonance frequency of the sub piezoelectric element vibrating in the sub vibration mode. Frequency varying means for causing the resonance frequency of the auxiliary vibration mode to always match the resonance frequency of the main vibration mode.

In the composite vibration generating ultrasonic vibrator according to the sixth aspect of the present invention, a plurality of pairs of piezoelectric elements having different vibration modes can be combined to vibrate simultaneously in different vibration modes of the main vibration mode and the sub vibration mode. In a composite vibration generating ultrasonic vibrator in which a vibrator portion vibrating in the sub-vibration mode is a combination of one or more main piezoelectric elements and one or more sub-piezoelectric elements, the sub piezoelectric vibrating in the sub vibration mode A frequency variable means for short-circuiting both ends of the element by a coil, forcibly changing a resonance frequency of the piezoelectric element vibrating in the auxiliary vibration mode by changing an inductance of the coil, and always providing a resonance frequency of the main vibration mode The resonance frequency of the sub-vibration mode is made to match.

That is, in the inventions according to claims 4 to 6, a plurality of pairs of piezoelectric elements having different vibration modes are combined.
It is possible to simultaneously vibrate in different vibration modes of the main vibration mode and the sub vibration mode, and the vibrator portion vibrating in the sub vibration mode is formed by combining one or more main piezoelectric elements and one or more sub piezoelectric elements. For a resonance frequency that vibrates in the main vibration mode in a composite vibration generating ultrasonic vibrator,
The resonance of the main vibration mode is always performed by forcibly changing the resonance frequency of the sub-piezoelectric element in the sub-vibration mode vibrating in another mode by using any one of the frequency variable means in the above-described invention. The resonance frequency of the sub-vibration mode is made to match the frequency, and the resonance frequency of the main vibration mode and the resonance frequency of the sub-vibration mode are forced to match, and a stable composite By obtaining vibration, the application range in the processing field such as cutting and grinding using ultrasonic waves is expanded, and high-quality processing can be expected.

In the composite vibration generating ultrasonic vibrator according to the seventh aspect of the invention, a plurality of pairs of piezoelectric elements having different vibration modes can be combined and simultaneously vibrated in different vibration modes of the main vibration mode and the sub vibration mode. In a composite vibration generating ultrasonic vibrator in which a vibrator portion that vibrates in the sub-vibration mode is a combination of one or more main piezoelectric elements and one or more sub-piezoelectric elements, the piezoelectric vibrating in the main vibration mode A voltage whose phase angle is shifted at the same frequency as the voltage applied to the element is applied to the auxiliary piezoelectric element vibrating in the auxiliary vibration mode, and the resonance frequency of the auxiliary piezoelectric element vibrating in the auxiliary vibration mode is forcibly changed. A frequency varying means for causing the resonance frequency of the sub-vibration mode to always match the resonance frequency of an integral multiple of the main vibration mode.

In the composite vibration generating ultrasonic vibrator according to the present invention, a plurality of pairs of piezoelectric elements having different vibration modes can be combined to vibrate simultaneously in different vibration modes of the main vibration mode and the sub vibration mode. In a composite vibration generating ultrasonic vibrator in which a vibrator portion vibrating in the sub-vibration mode is a combination of one or more main piezoelectric elements and one or more sub-piezoelectric elements, the sub piezoelectric vibrating in the sub vibration mode The two ends of the element are short-circuited at the same frequency as the voltage applied to the piezoelectric element vibrating in the main vibration mode and at a timing shifted in phase angle to forcibly change the resonance frequency of the sub piezoelectric element vibrating in the sub vibration mode. A frequency varying means for causing the resonance frequency of the sub-vibration mode to always match the resonance frequency of an integral multiple of the main vibration mode.

In the composite vibration generating ultrasonic vibrator according to the ninth aspect, a plurality of pairs of piezoelectric elements having different vibration modes can be combined and simultaneously vibrated in different vibration modes of the main vibration mode and the sub vibration mode. In a composite vibration generating ultrasonic vibrator in which a vibrator portion vibrating in the sub-vibration mode is a combination of one or more main piezoelectric elements and one or more sub-piezoelectric elements, the sub piezoelectric vibrating in the sub vibration mode A frequency variable means for short-circuiting both ends of the element by a coil and changing the inductance of the coil to forcibly change the resonance frequency of the piezoelectric element vibrating in the sub-vibration mode is always provided as an integral multiple of the main vibration mode. The resonance frequency of the sub-vibration mode is made to match the resonance frequency of.

That is, according to the present invention, a plurality of pairs of piezoelectric elements having different vibration modes can be combined to simultaneously vibrate in different vibration modes of the main vibration mode and the sub vibration mode. A vibrator portion that vibrates in the vibration mode is a composite vibration generating ultrasonic vibrator in which a pair or more of the main piezoelectric elements and a pair or more of the sub-piezo elements are combined. 4. A sub-vibration element in a sub-vibration mode vibrating in another mode.
By forcibly changing the resonance frequency using any of the frequency variable means in the described invention, so that the resonance frequency of the auxiliary vibration mode can always match the resonance frequency of an integral multiple of the main vibration mode, By forcibly changing the resonance frequency of the sub-vibration mode and always matching the resonance frequency of the sub-vibration mode to a resonance frequency that is an integral multiple of the main vibration mode, continuous stability that was impossible in the past was achieved The composite vibration can be generated, and the application range in the processing field such as cutting and grinding using ultrasonic waves is widened, and high-quality processing can be expected.

According to a tenth aspect of the present invention, in the composite vibration generating ultrasonic vibrator according to any one of the fourth to ninth aspects, a variable means for varying a voltage applied to the piezoelectric element vibrating in the main vibration mode. A structure capable of changing the amplitude of the main vibration mode, and a structure capable of changing the amplitude of the sub-vibration mode by changing the voltage applied to the piezoelectric element vibrating in the sub-vibration mode The phase angle of the piezoelectric element vibrating in the sub vibration mode is changed with respect to the phase of the voltage applied to the piezoelectric element vibrating in the main vibration mode, and the voltage and the phase applied to each are controlled. The control means is provided.

That is, the composite vibration generating ultrasonic vibrator according to any one of claims 4 to 9 has a structure in which the amplitude can be changed by changing the voltage applied to the terminals of the plurality of pairs of piezoelectric elements. At the same time, by controlling the phase angle of the voltage applied to each vibration mode, a vibration trajectory of a Lissajous waveform is generated at the tip of the vibrator, and the vibration trajectory can be stably arbitrarily controlled. By attaching a cutting tool to the cutting edge, vibration cutting with low cutting resistance can be realized, and particularly, high-precision cutting of highly brittle materials such as ceramics and glass can be realized with low cutting resistance unlike before. In addition, ultra-precision processing with low cutting resistance can be realized in fields such as grinding and milling.

[0046]

FIG. 1 shows a first embodiment of the present invention.
It will be described based on. This embodiment corresponds to the first aspect of the present invention.

First, a pair of main piezoelectric elements 1 for shaft vibration and a pair of sub-piezoelectric elements 2 for shaft vibration are sandwiched between the front horn 3 and the rear horn 4 and strongly tightened with fastening bolts 5. In the Langevin type shaft vibrator 6, the output signal of the voltage controlled oscillator 7 is amplified by the main output amplifier circuit 8 for shaft vibration, and connected so as to be inputted to the main piezoelectric element 1 via the vibration speed detector 9. . Here, the phase difference between the applied voltage and the current is detected by the vibration velocity detector 9, and the deviation from the resonance frequency is output as the frequency control voltage V 1 and fed back to the voltage control oscillator 7, whereby the PLL automatic tracking circuit 10 Is constituted, and the shaft vibration can continue the stable vibration at the resonance frequency.

On the other hand, the output of the voltage controlled oscillator 7 is connected so as to be input to the auxiliary piezoelectric element 2 via the phase controller 11 and the auxiliary output amplifier circuit 12 for shaft vibration. Here, the phase controller 11 can freely change the phase angle of the signal of the voltage controlled oscillator 7 by adjusting the phase with the variable resistor 14 for phase adjustment. When the phase is changed by the variable resistor 14 in this state, the oscillation frequency of the voltage controlled oscillator 7 changes freely according to the phase angle shift. That is, the resonance frequency of the Langevin-type shaft vibrator 6 changes freely. This is because the sub-piezoelectric element 2 driven by forcibly changing the phase of the drive voltage vibrates with a combined vector with the vibration phase mechanically driven by the main piezoelectric element 1, so that the sub-piezoelectric element apparently has It is presumed that the sound speed of 2 itself has changed. The phase controller 11 having these variable resistors 14 and the auxiliary output amplifying circuit 12 for shaft vibration constitute the frequency varying means 13.

As described above, according to the present embodiment, the Langevin-type shaft vibrator 6 is applied to the sub-piezoelectric element 2 by applying a voltage having the same frequency as the voltage applied to the main piezoelectric element 1 and having a phase angle shifted. Is provided, the resonance frequency of the Langevin-type shaft oscillator 6 can be arbitrarily determined only by changing the phase by the variable resistor 14.

A second embodiment of the present invention will be described with reference to FIG. Portions that are the same as or correspond to the portions described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted (the same applies to each of the following embodiments). This embodiment also corresponds to the first aspect of the present invention.

The Langevin type shaft oscillator 2 of the present embodiment
At 0, the signal of the oscillator 22 that can be adjusted to an arbitrary oscillation frequency by the variable resistor 21 for frequency adjustment is amplified by the main output amplifying circuit 8 for shaft vibration, and is output via the vibration speed detector 9 for the shaft vibration. Input to the main piezoelectric element 1. Similarly, the signal amplified by the shaft vibration sub-output amplifier circuit 12 from the oscillator 22 via the voltage control type phase controller 23 is input to the shaft vibration sub piezoelectric element 2. A detection signal for the resonance frequency of the Langevin-type shaft vibrator 20 detected by the vibration speed detector 9 is converted to a voltage control type phase controller 23 as a phase control voltage V2.
To control its phase angle. The vibration speed detector 9, the voltage control type phase controller 23, and the auxiliary output amplifying circuit 12 for shaft vibration constitute a frequency variable unit 24.

In such a configuration, when a signal of an arbitrary frequency is driven by the oscillator 22 through the main output amplifying circuit 8 for shaft vibration and the vibration speed detector 9, the main piezoelectric element 1 for shaft vibration is used. A signal of a difference between the resonance frequency of the mold shaft vibrator 20 and the driving frequency is output from the vibration speed detector 9 to the voltage control type phase controller 23 as the phase control voltage V2, and the voltage is used as the voltage of the feedback signal. The phase angle of the phase controller 23 is changed.

If the phase of the signal of the sub-piezoelectric element 2 for axial vibration greatly deviates from the signal applied to the main piezoelectric element 1 for axial vibration, the sound speed of the sub-piezoelectric element 2 itself for apparently axial vibration changes. The resonance frequency of the Langevin-type shaft oscillator 20 itself changes due to the phenomenon presumed to have occurred. The frequency of the oscillator 22 and the Langevin-type shaft oscillator 20
When the changed resonance frequency is matched, stable resonance vibration is continued.

Here, even if the resonance frequency of the Langevin-type shaft vibrator 20 changes due to a temperature change or a load change, the difference is used as the phase control voltage V2 to control the voltage control type phase controller 23 to further change the phase. By doing so, the resonance frequency of the Langevin-type shaft vibrator 20 can be forcibly and automatically adjusted to the oscillation frequency of the oscillator 22.

That is, in the conventional automatic tracking of the ultrasonic vibration, the oscillation frequency is changed according to the change in the resonance frequency of the vibrator. However, according to the present embodiment, the oscillation frequency of the oscillator 22 is forcibly set. The present invention provides a new method of adjusting the resonance frequency of the Langevin-type shaft oscillator 20 to the above. Further, it is also possible to drive a plurality of vibrators stably at the same frequency as in the method shown in FIG.

A third embodiment of the present invention will be described with reference to FIG. This embodiment also corresponds to the first aspect of the present invention.

This embodiment solves the problem of the ultrasonic power combiner 201 shown in FIG. 12 by developing the control method of the first embodiment shown in FIG. It was made. The length and width of the cross are １ ／ each
An ultrasonic power combiner 34 in which excitation vibrators 32a, 32b, and 32c are mounted on three surfaces of a power combining vibration body 31 having a wavelength (λ / 2), and a processing horn 33 is mounted on the remaining one surface.
, Three excitation vibrators 32a, 32b, 32c
Are each configured to include a main piezoelectric element 1 for shaft vibration and a sub piezoelectric element 2 for shaft vibration. Then, the synthesized ultrasonic power is obtained from the processing horn 33, but it is difficult for the conventional means to obtain an efficient output unless the electrical characteristics such as the resonance frequency of each vibrator match. .

In this regard, in the present embodiment, the output signal of the voltage controlled oscillator 7 is amplified by the main output amplifier circuit 8 for shaft vibration, and the output signal of the first excitation vibrator 32a is transmitted through the vibration speed detector 9a. Applied to the main piezoelectric element 1 for axial vibration. here,
The phase difference between the applied voltage and current is detected by a vibration speed detector 9a.
The PLL automatic tracking circuit 10 is configured by detecting the deviation from the resonance frequency and outputting the deviation from the resonance frequency as the frequency control voltage V1 and feeding it back to the voltage control oscillator 7, so that the shaft vibration continues to be stable at the resonance frequency. Becomes possible.

On the other hand, the output of the voltage controlled oscillator 7 is applied to the auxiliary piezoelectric element 2 for axial vibration via the auxiliary output amplifier circuit 12a for axial vibration via the phase controller 11a. Here, the phase controller 11 is adjusted by adjusting the variable resistor 14 for adjusting the phase.
“a” can freely change the phase angle of the signal of the voltage controlled oscillator 7. When the variable resistor 14 for phase adjustment is changed in this state, the oscillation frequency of the voltage controlled oscillator 7 changes freely according to the degree of the phase shift, and the resonance frequency of the excitation oscillator 32a changes freely. Will be.

Next, the output of the main output amplifier circuit 8 for shaft vibration is applied to the main piezoelectric element 1 for shaft vibration of the second vibrator 32b via the second vibration speed detector 9b. . The output of the voltage-controlled oscillator 7 is supplied to the second shaft oscillation sub-output amplifying circuit 12 via the voltage-controlled phase controller 11b.
b, and is applied to the auxiliary piezoelectric element 2 for axial vibration of the second excitation vibrator 32b. The third excitation vibrator 32c also has the same circuit configuration as the second excitation vibrator 32b (shown with a suffix "c"). Here, the operation of the first excitation vibrator 32a has been described based on FIG.

In the case of the second excitation vibrator 32b, the voltage applied to the main piezoelectric element 1 for axial vibration is equal to the voltage applied to the main piezoelectric element 1 for axial vibration of the first excitation vibrator 32a. Are identical. Therefore, when a signal deviating from the original resonance frequency is applied, the phase control voltage V2b corresponding to the deviation is output from the vibration velocity detector 9b, and the voltage control type phase controller 11b uses the signal to generate the phase control voltage V2b by the frequency deviation. The phase angle of the voltage controlled oscillator 7 is changed, and the voltage is amplified by the second auxiliary output amplifier circuit 12b for shaft vibration, and the second excitation oscillator 32b is amplified.
The secondary piezoelectric element 2 for axial vibration is driven to forcibly change the resonance frequency, and is stabilized at a frequency that matches the first vibration frequency.

The third excitation vibrator 32c operates according to the same principle, and accordingly, the three excitation vibrators 32a, 32b,
32c vibrate at the same frequency. Here, if multiple resonators whose electrical characteristics such as resonance frequency do not match are coupled, some spurious responses will appear due to the different resonance frequencies, making it impossible to perform ideal automatic tracking. If used continuously in such a state, the required ultrasonic power cannot be obtained, or a load is applied only to a specific vibrator, thereby damaging the vibrator or destroying the oscillator. Such troubles occur.

In order to avoid such a phenomenon, in the final stage of manufacturing the vibrator, for example, a method has been adopted in which the dimensions of the vibrator are trimmed or the frequency is adjusted so as to match each other. However, by using the countermeasure of the present embodiment, it is possible to realize a stable operation efficiently by adjusting the frequency easily without specially adjusting the shape of the vibrator. Disappears.

A fourth embodiment of the present invention will be described with reference to FIG. This embodiment corresponds to the second aspect of the present invention.

The Langevin type shaft oscillator 4 of the present embodiment
At 0, a signal of an oscillator 22 that can be adjusted to an arbitrary oscillation frequency by a variable resistor 21 for frequency adjustment is amplified by a main output amplifier circuit 8 for shaft vibration, and is output via a vibration speed detector 9 for a shaft vibration. It is connected so as to be applied to the main piezoelectric element 1. Similarly, a signal from the oscillator 22 is connected to the auxiliary piezoelectric element 2 for axial vibration via the short circuit 41 and the conjugate matching coil 42 via the voltage control type phase controller 23. The inductance of the conjugate matching coil 42 is set to a value that is conjugate with the braking capacity of the sub piezoelectric element 2 for axial vibration. The short circuit 41 is connected to the coupling transformer 4.
3, capacitor 44, two flywheel diodes 4
5a, 45b, two FETs 46a, 46b, and two inverting amplifiers 47a, 47b. The short circuit 41 is formed by two inverting amplifiers 47a and 47b.
FETs 46a and 46b are turned on alternately, and if a DC voltage is applied to the neutral point 0 of the coil on the secondary side of the coupling transformer 43, an amplifier circuit widely known as a push-pull circuit is obtained. In this embodiment mode, no voltage is applied. The detection signal for the resonance frequency of the vibrator detected by the vibration speed detector 9 controls the phase angle of the voltage control type phase controller 23 as the phase control voltage V2. These vibration velocity detector 9 and phase controller 2
3. The frequency varying means 48 is constituted by the short circuit 41 and the conjugate matching coil 42.

In such a circuit configuration, the oscillator 22
When the signal of an arbitrary frequency drives the main piezoelectric element 1 for shaft vibration via the main output amplifier circuit 8 for shaft vibration and the vibration speed detector 9, the difference between the resonance frequency of the original vibrator and the driven frequency is obtained. Signal from the vibration velocity detector 9 to the phase control voltage V
2, and changes the phase angle of the voltage control type phase controller 23 according to the voltage V2. Here, the two FETs 46a and 46b are alternately turned on via the two inverting amplifiers 47a and 47b at the phase angle changed by the voltage control type phase controller 23. The vibrator vibrates by a signal applied to the main piezoelectric element 1 for shaft vibration. At the same time, a voltage synchronized with the vibration frequency is generated in the sub-piezoelectric element 2 for shaft vibration due to a piezoelectric effect due to vibration. A piezoelectric element has a reversible relationship between its deformation and a voltage, and has a piezoelectric effect of deforming when a voltage is applied and generating a voltage when deformed.

In this embodiment corresponding to the second aspect of the present invention, the generated voltage is used. The voltage generated in the auxiliary piezoelectric element 2 for axial vibration is applied to the short circuit 41 via the coil 42 for conjugate matching, so that the coupling transformer 43
Voltage is induced on the secondary side of. On the other hand, two FETs 46
a and 46b are repeatedly turned on and off, so that the voltage generated in the sub-piezoelectric element 2 for axial vibration is short-circuited at the timing when the phase is shifted by the voltage control type phase controller 23, and the phase shift level is obtained. That is, the resonance frequency of the vibrator is forcibly changed by changing the phase angle. Here, the present inventor has previously found that the resonance frequency of the vibrator is largely different between an open state where no auxiliary piezoelectric element 2 for shaft vibration is connected and a state where it is short-circuited to the ground. This is presumably because the sound speed changes when the impedance of the piezoelectric element changes. As a means for utilizing this phenomenon and for continuously varying the resonance frequency, a frequency variable means 48 for continuously varying the resonance frequency of the vibrator by continuously varying the phase angle and short-circuiting the same is embodied. It is.

In such a configuration, when a signal of an arbitrary frequency is driven by the oscillator 22 through the main output amplifier circuit 8 for shaft vibration and the vibration speed detector 9 to drive the main piezoelectric element 1 for shaft vibration, the original vibration A signal proportional to the difference between the resonance frequency of the transducer and the driving frequency is output from the vibration velocity detector 9 as the phase control voltage V2, and the phase control voltage V2 is output as a feedback signal voltage by the phase angle (phase difference) of the voltage control type phase controller 23. )change. If the phase angle of the short-circuit of the sub-piezoelectric element 2 for axial vibration greatly deviates from the signal applied to the main piezoelectric element 1 for axial vibration, the sound velocity of the main piezoelectric element 1 for axial vibration changes forcibly. As a result, the resonance frequency of the vibrator itself changes. Then, when the drive frequency of the oscillator 22 matches the changed resonance frequency of the vibrator, stable resonance vibration is continued. Here, even if the resonance frequency of the vibrator changes due to a temperature change, a load change, or the like, the difference is used as the phase control voltage V2 to control the voltage control type phase controller 23, and the phase is further changed to forcibly change the phase. The resonance frequency of the vibrator can be automatically adjusted to the oscillation frequency of the oscillator 22.

That is, in the conventional automatic tracking of the ultrasonic vibration, the oscillation frequency is changed in accordance with the change in the resonance frequency of the vibrator. In the present embodiment, the same as in the above-described embodiment. In addition, the provision of the frequency varying means 48 makes it possible to forcibly adjust the resonance frequency of the vibrator to the oscillation frequency of the oscillator 22.

FIGS. 5 and 6 show a fifth embodiment of the present invention.
It will be described based on. This embodiment corresponds to the third aspect of the present invention.

The Langevin-type shaft oscillator 5 of the present embodiment
At 0, the signal of the oscillator 22 that can be adjusted to an arbitrary oscillation frequency by the variable resistor 21 for frequency adjustment is amplified by the output amplifier circuit 51 for shaft vibration, and the main piezoelectric element for shaft vibration is amplified via the vibration speed detector 9. It is connected so as to be applied to the element 1. The vibration speed detector 9 generates an inductance control voltage V3 which is a signal corresponding to a deviation between the resonance frequency of the vibrator and the driving frequency. The auxiliary piezoelectric element 2 for shaft vibration is grounded via an inductance variable circuit 52 whose inductance can be varied according to the inductance control voltage V3. This inductance variable circuit 52 constitutes a frequency variable means 53. A detection signal corresponding to the deviation between the original resonance frequency of the vibrator and the driving frequency detected by the vibration speed detector 9 is given as an inductance control voltage V3 to the inductance variable circuit 52 to control the inductance.

FIG. 6 shows a detailed circuit example of the inductance variable circuit 52. The variable coil 54 is a variable coil primary side 5
4a and the variable coil secondary side 54b, terminals A and B of the inductance variable circuit 52 are connected to the variable coil 1
It matches the terminals A and B on the next side 54a. One terminal of the variable coil secondary side 54b is grounded via a DC power supply 55. The other terminal is connected to a constant current circuit 59 via a low-pass filter 58 formed by a choke coil 56 and a capacitor 57. The constant current circuit 59 includes a transistor 60, a detecting resistor 61, and an operational amplifier 62. An inductance control voltage V3 is applied to a positive input of the operational amplifier 62, and a DC stabilized current corresponding to the voltage is supplied to the variable coil secondary. It is configured to flow on the side 54b.

The high frequency voltage of the ultrasonic frequency induced on the secondary side 54b of the variable coil by the low-pass filter 58 constituted by the choke coil 56 and the capacitor 57 does not flow into the constant current circuit 59. This allows
A DC magnetic field is superimposed on the core of the variable coil 54, and the variable coil primary side 54b
Is continuously changed in accordance with the voltage level of the inductance control voltage V3.

In such a circuit configuration, the oscillator 22
Signal of an arbitrary frequency due to the shaft vibration output amplifying circuit 51
When the main piezoelectric element 1 for shaft vibration is driven via the vibration speed detector 9, the vibrator vibrates at a frequency corresponding to the signal of the oscillator 22. At the same time, a high frequency voltage synchronized with the vibration frequency is generated in the auxiliary piezoelectric element 2 for shaft vibration due to the piezoelectric effect of the vibration, and flows to the ground via the variable inductance circuit 52. Here, when the inductance of the inductance variable circuit 52 changes, the resonance frequency of the vibrator also changes. This is because, when viewed from the main piezoelectric element 1 for axial vibration, the impedance of the sub piezoelectric element 2 for axial vibration changes, thereby changing the sound speed of the sub piezoelectric element 2 for axial vibration. As a result, the resonance frequency of the vibrator is changed. Is presumed to have been changed.

Here, a signal proportional to the deviation between the resonance frequency of the original vibrator and the driving frequency is applied to the vibration speed detector 9.
Is output as an inductance control voltage V3 from
If this is used as the voltage of the feedback signal to change the inductance of the inductance variable circuit 52,
When the frequency of the oscillator 22 matches the changed resonance frequency of the vibrator, stable resonance vibration is continued. At this time, even if the resonance frequency of the vibrator changes due to a temperature change, a load fluctuation, or the like, the difference is used as the inductance control voltage V3 to control the inductance variable circuit 52 to further change the inductance, thereby forcing the resonance of the vibrator. It is possible to automatically adjust the frequency to the oscillation frequency of the oscillator.

That is, in the conventional automatic tracking of ultrasonic vibration, the oscillation frequency is changed in accordance with the change in the resonance frequency of the vibrator. As in the above-described embodiments, the resonance frequency of the vibrator can be forcibly adjusted to the oscillation frequency of the oscillator 22.

A sixth embodiment of the present invention will be described with reference to FIG. This embodiment corresponds to the invention described in claim 4.

This embodiment is applied to a BL type composite vibrator 70 which is a composite vibration generating ultrasonic vibrator. That is, the main piezoelectric element 1 for shaft vibration and the sub piezoelectric element 2 for shaft vibration
In addition to the above, the flexural vibration piezoelectric element 7 having a different vibration mode
1A and 71B. That is, the bending vibration piezoelectric elements 71A and 71B, the main piezoelectric element 1 for shaft vibration, and the sub piezoelectric element 2 for shaft vibration are sandwiched between the front horn 3 and the rear horn 4 and strongly tightened with the fastening bolt 5. In the -L-type composite vibrator 70, the signal of the voltage controlled oscillator 7 is amplified by the output amplifier circuit 72 and applied to the flexural vibration piezoelectric elements 71A and 71B via the flexural vibration speed detector 73, so that the main vibration The mode generates flexural vibration.
Here, the flexural vibration speed detector 73 outputs a voltage proportional to the deviation between the resonance frequency of the original flexural vibrator and the frequency applied to the piezoelectric elements 71A and 71B.
When the voltage control oscillator 7 is controlled using the frequency control voltage V4 as a feedback signal, the deflection vibration becomes a PLL type automatic tracking, and the vibration can be stably continued at the resonance frequency.

On the other hand, the output of the output amplifying circuit 72 is also applied to the main piezoelectric element 1 for shaft vibration via the shaft vibration speed detector 74, and the same signal as the resonance frequency of the flexural vibration is applied. Further, the signal from the voltage controlled oscillator 7 is amplified by the shaft vibration auxiliary output amplifier circuit 12 via the voltage control type phase controller 23 and then applied to the shaft vibration auxiliary piezoelectric element 2.
Here, the shaft vibration velocity detector 74, the voltage control type phase controller 23, and the sub-output amplifier circuit 12
(Corresponding to the frequency variable means 24).
The phase angle of the voltage control type phase controller 23 is controlled by the phase control voltage V2 detected by the shaft vibration velocity detector 74. In the case of this composite vibrator 70, the main piezoelectric element 1 for axial vibration is always driven at the resonance frequency of the flexural vibration, but is proportional to the deviation between the resonance frequency of the original shaft and the resonant frequency of the flexural vibration. The signal becomes a feedback signal, and by controlling the phase angle of the signal applied to the auxiliary piezoelectric element 2 for shaft vibration as the phase control voltage V2, the resonance frequency of shaft vibration is forcibly adjusted to the resonance frequency of flexural vibration. That is, the resonance frequency of the shaft vibration (sub-vibration mode) automatically tracks the resonance frequency of the flexural vibration (main vibration mode), and a stable composite vibration can be realized at the same frequency.

In the present embodiment, the frequency variable means 75 corresponding to the frequency variable means 24 is used, but a frequency variable means corresponding to the frequency variable means 13, 48 or 53 may be used. , 6)).

A seventh embodiment of the present invention will be described with reference to FIG. This embodiment corresponds to the tenth aspect of the present invention.

This embodiment is also applied to a BL type composite vibrator 80 which is a composite vibration generating ultrasonic vibrator.

This embodiment is an improvement of the sixth embodiment. Piezoelectric element 71 for flexural vibration
A, 71B, a main piezoelectric element 1 for shaft vibration, and a sub piezoelectric element 2 for shaft vibration are sandwiched between a front horn 3 and a rear horn 4,
BL type vibrator 8 strongly tightened with fastening bolts 5
At 0, the signal of the voltage controlled oscillator 7 is amplified by a flexural vibration output amplifying circuit 82 whose amplitude can be controlled by a flexural vibration amplitude control variable resistor 81, and the flexural vibration output is detected by a flexural vibration speed detector 73. A configuration is applied to the piezoelectric elements 71A and 72B to generate flexural vibration. Here, the flexural vibration velocity detector 73 outputs a voltage proportional to the deviation between the resonance frequency of the original flexural vibrator and the frequency applied to the piezoelectric element as the frequency control voltage V1, and this frequency control voltage V1 is fed back. If the voltage controlled oscillator 7 is controlled as a signal, the flexural vibration becomes PLL type automatic tracking, and the vibration can be stably continued at the resonance frequency.

On the other hand, the signal of the voltage controlled oscillator 7 passes through a vibration trajectory controlling phase controller 84 whose phase angle can be arbitrarily varied by a phase adjusting variable resistor 83 and a variable resistor 85 for controlling the shaft vibration amplitude. Is amplified by a shaft vibration output amplifying circuit 86 which can be controlled by the shaft vibration, and applied to the main piezoelectric element 1 for shaft vibration via a shaft vibration speed detector 74. The phase angle is the same as the resonance frequency of the flexural vibration. The changed signal is applied. Further, a signal from the voltage controlled oscillator 7 is amplified by the shaft output auxiliary output amplifier circuit 12 via the voltage control type phase controller 23 and applied to the shaft driven auxiliary piezoelectric element 2. The phase angle of the voltage control type phase controller 23 is controlled in accordance with the phase control voltage V2 detected by the shaft vibration speed detector 74. That is,
In contrast to the sixth embodiment, a control means 87 including a vibration trajectory control phase controller 84 and a shaft vibration output amplifier circuit 86 is added. That is, in the present embodiment, the variable resistor 81 for controlling the bending vibration amplitude has a structure in which the voltage applied to the bending vibration (main vibration) mode is changed to change the amplitude of the bending vibration, and The variable resistor 85 for controlling the shaft vibration amplitude has a structure capable of changing the amplitude of the shaft vibration mode by changing the voltage applied to the shaft vibration (sub-vibration) mode. Is changed with respect to the phase of the voltage in the flexural vibration mode, and a voltage and a phase applied to each are controlled to generate a vibration trajectory of a Lissajous waveform, and the vibration trajectory is arbitrarily controlled.

In the case of the composite vibrator 80 having such a configuration,
Main piezoelectric element 1 for shaft vibration always at resonance frequency of flexural vibration
Is also driven, but a signal proportional to the deviation between the resonance frequency of the shaft vibration and the frequency of the bending vibration becomes a feedback signal as in the principle described in the sixth embodiment, and is used as a phase control voltage V2 for the shaft vibration. By controlling the phase of the signal applied to the auxiliary piezoelectric element 2, the resonance frequency of the axial vibration is forcibly adjusted to the resonance frequency of the flexural vibration, and a stable composite vibration can be realized at the same frequency. Here, if the phase angle is adjusted by the variable resistor 83 for phase adjustment, it is possible to draw a locus of an arbitrary Lissajous waveform.

For example, if the mutual phase angle is set to 90 degrees, the tip of the vibrator draws a locus represented by elliptical vibration S1, and if the vibration amplitudes of the flexural vibration and the axial vibration are equal, a true circular locus is drawn. It is possible. Here, by adjusting the variable resistor 81 for controlling the bending vibration amplitude and the variable resistor 85 for controlling the shaft vibration amplitude, it is possible to draw the trajectories of the Lissajous waveforms having various ellipticities. Further, the inclination of the ellipse can be adjusted by adjusting the variable resistor 83 for phase adjustment,
For example, a vibration locus such as an inclined elliptical vibration S2 can be freely realized.

An eighth embodiment of the present invention will be described with reference to FIG. This embodiment also corresponds to the invention described in claim 10.

In this embodiment, the flexural vibration piezoelectric elements 71C and 71C 'having the same characteristics and the axial vibration sub-piezoelectric element 2 are sandwiched between the front horn 3 and the rear horn 4, and the fastening bolt 5 is used. A B-L type composite vibrator 90 that is strongly tightened is used.

Here, a pair of flexural vibration piezoelectric elements 71
C and 71C 'are formed by dividing an annular piezoelectric element in which the piezoelectric directions thereof are opposed to each other into two and forming a semi-annular shape.
(Represented by → ←). However, the effect is the same even if the two sets are configured with the piezoelectric directions facing the minus side (represented by ← →). In this case, if the driving voltages are applied in opposite phases without using the same electrode, the other piezoelectric element contracts in the cycle where one piezoelectric element expands, so that flexural vibration can be easily generated. become. Further, if a driving voltage having the same phase is applied to each electrode, each of the flexural vibration piezoelectric elements 71C and 71c 'repeats expansion and contraction at the same period, so that axial vibration can be generated. Therefore, by combining the same flexural vibration piezoelectric elements 71C and 71c ',
By changing the phase of the drive voltage applied to each of them, it is possible to generate both axial vibration and flexural vibration.

Here, one terminal A on the secondary side of the vibration synthesizing transformer 91 is connected to the terminal A of one flexural vibration piezoelectric element 71C, and the other terminal B on the secondary side of the vibration synthesizing transformer 91 is connected. Is connected to the terminal B of the other flexural vibration piezoelectric element 71C ', and if a drive voltage is applied to the neutral point 0 on the secondary side of the vibration synthesizing transformer 91, the flexural vibration piezoelectric element 71C'
C and 71C 'are applied with the same-phase drive voltage, so that axial vibration is generated. At the same time, if a drive voltage is separately applied to the primary side of the vibration synthesizing transformer 91, voltages having opposite phases appear on the terminals A and B on the secondary side of the vibration synthesizing transformer 91, so that the flexural vibration piezoelectric elements 71C, 71C ', It is possible to generate flexural vibration.

Therefore, the use of the vibration synthesizing transformer 91 makes it possible to simplify the vibrator structure of the BL type composite vibrator 9.
0 can be realized.

Here, the signal of the voltage controlled oscillator 7 is amplified by a flexural vibration output amplifying circuit 82 whose amplitude can be controlled by a flexural vibration amplitude control variable resistor 81, and then transmitted through a flexural vibration speed detector 73. Connected to the transformer 91 for vibration synthesis. The flexural vibration velocity detector 73 outputs a voltage proportional to the deviation between the resonance frequency of the original flexural vibrator and the frequency applied to the piezoelectric element as a frequency control voltage V1, and uses this frequency control voltage V1 as a feedback signal. If the control oscillator 7 is controlled, the flexural vibration becomes a PLL type automatic tracking, and the vibration can be stably continued at the resonance frequency.

On the other hand, the signal of the voltage controlled oscillator 7 passes through a vibration trajectory controlling phase controller 84 whose phase angle can be arbitrarily varied by a phase adjusting variable resistor 83 and a variable resistor 85 for shaft vibration amplitude control. Is amplified by a shaft vibration output amplifying circuit 86 capable of controlling the vibration, and is connected via a shaft vibration speed detector 74 to a neutral point on the secondary side of the vibration synthesizing transformer 91 so as to be connected. A signal having the same resonance frequency but a changed phase angle is applied. Further, the signal from the voltage controlled oscillator 7 is amplified by the auxiliary output amplifier circuit 12 for shaft vibration via the voltage control type phase controller 23 so that the auxiliary piezoelectric element 2 for shaft vibration is amplified.
Is applied. The phase angle of the voltage control type phase controller 23 is controlled by the phase control voltage V2 detected by the shaft vibration velocity detector 74.

In the case of the BL composite vibrator 90 of this embodiment, a stable composite vibration can be realized by the same principle as in the case of the seventh embodiment shown in FIG. This means that the piezoelectric elements 71C and 71C 'simultaneously perform the operations of the flexural vibration piezoelectric elements 71A and 71B and the axial vibration main piezoelectric element 1 in the seventh embodiment. Therefore, if the phase angle is adjusted by the variable resistor 83 for phase adjustment, it is possible to draw an arbitrary Lissajous waveform trajectory at the tip of the vibrator.

For example, if the mutual phase angle is set to 90 degrees, the tip of the vibrator draws a locus indicated by elliptical vibration S1, and if the vibration amplitudes of the flexural vibration and the axial vibration are equal, a true circular locus is drawn. It is possible. Here, by adjusting the variable resistor 81 for controlling the bending vibration amplitude and the variable resistor 85 for controlling the shaft vibration amplitude, it is possible to draw the trajectories of the Lissajous waveforms having various ellipticities. Further, the inclination of the ellipse can be adjusted by adjusting the variable resistor 83 for phase adjustment, and a vibration trajectory such as an inclined elliptical vibration S2 can be freely realized.

A ninth embodiment of the present invention will be described with reference to FIG. This embodiment is equivalent to the seventh aspect of the present invention.

The present embodiment is applied to a BL type composite vibrator 100 which is a composite vibration generating ultrasonic vibrator. The piezoelectric elements 71A and 71B for bending vibration, the main piezoelectric element 1 for shaft vibration, and the sub-piezoelectric element 2 for shaft vibration are sandwiched between the front horn 3 and the rear horn 4, and are strongly tightened with fastening bolts 5. In the L-type composite vibrator 100, after the signal of the voltage controlled oscillator 7 is frequency-divided by the frequency dividing circuit 101 into a fractional integer, the signal is subjected to flexural vibration whose amplitude can be controlled by a variable resistor 81 for flexural vibration amplitude control. Amplified by the output amplifier circuit 82 for
The flexural vibration is applied to the flexural vibration piezoelectric elements 71A and 71B via the flexural vibration speed detector 73 to generate flexural vibration.

Here, the deflection vibration velocity detector 73
A voltage proportional to the deviation between the resonance frequency of the original flexural vibrator and the frequency applied to the piezoelectric element is defined as a frequency control voltage V1.
If the voltage control oscillator 7 is controlled using the frequency control voltage V1 as a feedback signal, the flexural vibration becomes PLL type automatic tracking, and the vibration can be stably continued at the resonance frequency.

On the other hand, the variable resistor 85 for controlling the shaft vibration amplitude
By amplifying the signal of the voltage controlled oscillator 7 by the shaft vibration output amplifier circuit 86 whose amplitude can be controlled by the above and inputting the amplified signal to the main piezoelectric element 1 for shaft vibration via the shaft vibration speed detector 74, the flexural vibration can be reduced. A signal having a frequency that is an integral multiple of the resonance frequency is applied. Further, a signal from the voltage controlled oscillator 7 is amplified by the shaft output auxiliary output amplifier circuit 12 via the voltage control type phase controller 23 and applied to the shaft driven auxiliary piezoelectric element 2. The phase angle of the voltage control type phase controller 23 is controlled by the phase control voltage V2 detected by the shaft vibration velocity detector 74.

The B-L type composite vibrator 10 having the above configuration
In the case of 0, the main piezoelectric element 1 for shaft vibration is always driven at a frequency that is an integral multiple of the resonance frequency of the flexural vibration. However, the deviation between the original resonance frequency of the shaft and a frequency that is an integral multiple of the flexural vibration is obtained. Becomes a feedback signal, and by controlling the phase of the signal applied to the auxiliary piezoelectric element 2 for shaft vibration as the phase control voltage V2, the resonance frequency of the shaft vibration is forced to be an integral multiple of the resonance frequency of the bending vibration. Since the frequency is adjusted to the frequency, stable composite vibration can be realized.

For example, the dividing ratio of the dividing circuit 101 is set to 1/2.
In this case, it is possible to draw a trajectory of a Lissajous waveform such as the figure-eight vibration S3 at the tip of the vibrator.
Then, by adjusting the variable resistor 81 for controlling the deflection vibration amplitude and the variable resistor 85 for controlling the shaft vibration amplitude, 8
Trajectories having different aspect / width ratios can be freely drawn as the amplitude of the figure vibration S3.

In this embodiment, the frequency variable means 75 corresponding to the frequency variable means 24 is used, but a frequency variable means corresponding to the frequency variable means 13, 48 or 53 may be used. , 9)).

A tenth embodiment of the present invention will be described with reference to FIG. This embodiment corresponds to the tenth aspect of the present invention.

This embodiment is an improvement of the ninth embodiment. Piezoelectric element 71 for flexural vibration
A, 71B, a main piezoelectric element 1 for shaft vibration and a sub-piezoelectric element 2 for shaft vibration are sandwiched between a front horn 3 and a rear horn 4, and are strongly tightened with fastening bolts 5. At 110, the signal of the voltage controlled oscillator 7 is frequency-divided by the frequency dividing circuit 101 to be a fraction of an integer, and amplified by a flexural vibration output amplifier circuit 82 whose amplitude can be controlled by a flexural vibration amplitude controlling variable resistor 81. Then, a configuration is adopted in which flexural vibration is applied to the flexural vibration piezoelectric elements 71A and 71B via the flexural vibration speed detector 73 to generate flexural vibration.

Here, the deflection vibration velocity detector 73
A voltage proportional to the deviation between the resonance frequency of the original flexural vibrator and the frequency applied to the piezoelectric element is defined as a frequency control voltage V1.
If the voltage control oscillator 7 is controlled using the frequency control voltage V1 as a feedback signal, the flexural vibration becomes PLL type automatic tracking, and the vibration can be stably continued at the resonance frequency.

On the other hand, the signal of the voltage controlled oscillator 7 passes through a vibration trajectory control phase controller 84 in which the phase angle can be arbitrarily varied by a phase adjustment variable resistor 83, and a shaft oscillation amplitude control variable resistor 85. Is amplified by a shaft vibration output amplifying circuit 86 which can be controlled by the shaft vibration speed detector 74 and applied to the shaft vibration main piezoelectric element 1 via a shaft vibration speed detector 74. The phase angle is a frequency that is an integral multiple of the resonance frequency of the flexural vibration. The changed signal is applied.
Further, a signal from the voltage controlled oscillator 7 is amplified by the shaft output auxiliary output amplifier circuit 12 via the voltage control type phase controller 23 and applied to the shaft driven auxiliary piezoelectric element 2. The phase angle of the voltage control type phase controller 23 is controlled by the phase control voltage V2 detected by the shaft vibration velocity detector 74.

That is, in contrast to the ninth embodiment, the vibration trajectory control phase controller 84 and the shaft vibration output amplifying circuit 8
6 is added. That is, in the present embodiment, the variable resistor 8 for controlling the flexural vibration amplitude is used.
1 has a structure in which the amplitude of the bending vibration can be changed by changing the voltage applied to the bending vibration (main vibration) mode, and the shaft vibration (sub vibration) is controlled by the variable resistor 85 for controlling the shaft vibration amplitude. The control means 87 has a structure in which the amplitude of the axial vibration mode can be changed by also changing the voltage applied to the mode. By controlling the voltage and phase to generate a vibration trajectory of the Lissajous waveform,
The vibration trajectory is arbitrarily controlled.

In the case of the composite vibrator 110 having such a configuration, the main piezoelectric element 1 for axial vibration is always driven at a frequency that is an integral multiple of the resonant frequency of flexural vibration. And a signal proportional to the deviation between the frequency and an integral multiple of the deflection vibration becomes a feedback signal, and the phase control voltage V2 is used to control the phase of the signal applied to the sub-piezoelectric element 2 for shaft vibration, thereby forcing the resonance frequency of the shaft vibration. The frequency is adjusted to an integral multiple of the resonance frequency of the flexural vibration, and stable composite vibration can be realized.

Here, the dividing ratio of the dividing circuit 101 is set to 1/2.
And the phase angle is adjusted by the variable resistor 83 for adjusting the phase, it is possible to draw an arbitrary Lissajous waveform trajectory. For example, if the mutual phase angle is set to 45 degrees, the tip of the vibrator will draw a trajectory of the shape shown in the Lissajous waveform S4 with the phase shifted, and if the mutual phase angle is set to 90 degrees, the tip of the vibrator will be described. The section can draw a locus like a sine wave as shown in the Lissajous waveform S5 with the phase shifted. Further, by adjusting the variable resistor 81 for controlling the deflection vibration amplitude and the variable resistor 85 for controlling the shaft vibration amplitude, it is possible to draw the trajectories of Lissajous waveforms having various aspect / width ratios. . Further, when the frequency division ratio of the frequency dividing circuit 101 is set to 1/3, a vibration trajectory such as a Lissajous waveform S6 having a shifted phase can be realized. As described above, various vibration trajectories can be obtained by changing the setting of the division ratio, the phase angle, and the amplitude.

[0110]

According to the first aspect of the present invention, a voltage is applied to the main piezoelectric element to vibrate, and a voltage is applied to the sub-piezoelectric element at the same frequency but with a phase angle shifted. It is possible to forcibly shift the resonance frequency of the transducer to an arbitrary frequency and to perform stable vibration by automatic tracking.For example, even when driving a plurality of transducers at the same frequency as in an ultrasonic power synthesizer, it is easy to use. Efficient and stable operation can be realized by matching the frequencies, and the problem of aging can be eliminated.

According to the second aspect of the present invention, a voltage is applied to at least one pair of main piezoelectric elements to vibrate, and the remaining one or more sub piezoelectric elements have a phase angle at the same frequency as the voltage applied to the main piezoelectric element. The two ends of the sub piezoelectric element are short-circuited at the shifted timing, so that the resonance frequency of the ultrasonic vibrator is forcibly shifted to an arbitrary frequency and stable vibration by automatic tracking becomes possible. Even when a plurality of vibrators are driven at the same frequency as in a power combiner, the frequencies can be easily matched to realize an efficient and stable operation, and the problem of aging can be eliminated.

According to the third aspect of the present invention, when a voltage is applied to at least one pair of the main piezoelectric elements to vibrate, a coil is connected to the remaining one or more sub-piezoelectric elements and both ends of the sub-piezoelectric elements are connected. And the inductance of the coil is changed, so that the resonance frequency of the ultrasonic vibrator is forcibly shifted and stable vibration by automatic tracking becomes possible. Even when these vibrators are driven at the same frequency, the frequencies can be easily matched to realize an efficient and stable operation, and the problem of aging can be eliminated.

According to the invention set forth in claims 4 to 6, it is possible to simultaneously vibrate in different vibration modes of the main vibration mode and the sub vibration mode by combining a plurality of pairs of piezoelectric elements having different vibration modes. A vibrator portion that vibrates in the mode is a composite vibration generating ultrasonic vibrator in which one or more pairs of main piezoelectric elements and one or more sub-piezoelectric elements are combined. 2. The sub-piezoelectric element of the sub-vibration mode vibrating in the mode is described above.
According to the invention described in any one of (3) to (3), any one of the frequency variable means is used to forcibly match, so that a stable composite vibration can be continuously obtained, and a processing field such as cutting or grinding using ultrasonic waves. Application range is widened and high quality processing can be expected.

According to the seventh to ninth aspects of the present invention, a plurality of pairs of piezoelectric elements having different vibration modes can be combined to vibrate simultaneously in different vibration modes of the main vibration mode and the sub vibration mode. A vibrator portion that vibrates in the mode is a composite vibration generating ultrasonic vibrator in which one or more pairs of main piezoelectric elements and one or more sub-piezoelectric elements are combined. 2. The sub-piezoelectric element of the sub-vibration mode vibrating in the mode is described above.
Since the resonance frequency is forcibly changed by using any one of the frequency variable means according to the inventions described in (3) to (3), the resonance frequency of the sub-vibration mode always coincides with the resonance frequency of an integral multiple of the main vibration mode. It is possible to generate a stable and complex vibration continuously, which is not possible with the above, and the application range in the processing field such as cutting and grinding using ultrasonic waves is widened, and high quality processing can be expected.

According to the tenth aspect, the fourth aspect is provided.
10. The composite vibration generating ultrasonic vibrator according to any one of 9 to 9, wherein the voltage applied to the terminals of each of the plurality of pairs of piezoelectric elements is changed so that the amplitude can be changed, and simultaneously applied to each vibration mode. By controlling the phase angle of the voltage, a vibration trajectory of a Lissajous waveform is generated at the tip of the vibrator, and the vibration trajectory can be controlled stably and arbitrarily.
For example, by attaching a cutting tool to the cutting edge, vibration cutting with low cutting resistance can be realized, and in particular, high-precision cutting of highly brittle materials such as ceramics and glass can be realized with unprecedented low cutting resistance, and grinding and milling. Ultra-precision machining with low cutting force can be realized in the field of machining.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an ultrasonic transducer according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an ultrasonic transducer according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of an ultrasonic transducer according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of an ultrasonic vibrator showing a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of an ultrasonic vibrator showing a fifth embodiment of the present invention.

FIG. 6 is a circuit diagram showing a configuration example of the variable inductance circuit.

FIG. 7 is a configuration diagram of a composite vibrator showing a sixth embodiment of the present invention.

FIG. 8 is a configuration diagram of a composite vibrator showing a seventh embodiment of the present invention.

FIG. 9 is a configuration diagram of a composite vibrator showing an eighth embodiment of the present invention.

FIG. 10 is a configuration diagram of a composite vibrator showing a ninth embodiment of the present invention.

FIG. 11 is a configuration diagram of a composite vibrator showing a tenth embodiment of the present invention.

FIG. 12 is a configuration diagram showing a general ultrasonic power synthesizer.

FIG. 13 is a configuration diagram showing a conventional TL-type composite vibrator.

FIG. 14 is a configuration diagram showing a conventional Langevin type BL composite oscillator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main piezoelectric element 2 Sub piezoelectric element 13 Frequency variable means 24 Frequency variable means 48 Frequency variable means 53 Frequency variable means 81 Variable means 85 Variable means 87 Control means

Continued on the front page F-term (reference) FF33 FF40

Claims (10)

[Claims] 1. An ultrasonic vibrator comprising a combination of at least one pair of main piezoelectric elements and at least one pair of sub-piezoelectric elements, wherein, when a drive voltage is applied to at least one pair of the main piezoelectric elements and vibrated, at least the remaining A frequency variable unit that forcibly changes the resonance frequency of the vibrator by applying a voltage having the same frequency as the voltage applied to the main piezoelectric element to the pair of sub piezoelectric elements and having a phase angle shifted therefrom. Ultrasonic vibrator characterized. 2. An ultrasonic vibrator comprising a combination of at least one pair of main piezoelectric elements and at least one pair of sub-piezoelectric elements. A frequency variable unit that forcibly changes the resonance frequency of the vibrator by short-circuiting both ends of the pair of sub-piezoelectric elements at the same frequency as the voltage applied to the main piezoelectric element and at a timing shifted in phase angle. Ultrasonic vibrator characterized. 3. An ultrasonic vibrator in which a pair of at least one main piezoelectric element and a pair of at least one sub-piezoelectric element are combined. An ultrasonic vibrator comprising: a frequency variable unit that short-circuits both ends of a pair of the sub-piezoelectric elements with a coil and changes an inductance of the coil to forcibly change a resonance frequency of the vibrator. 4. A plurality of pairs of piezoelectric elements having different vibration modes can be combined to simultaneously vibrate in different vibration modes of a main vibration mode and a sub vibration mode, and a pair of vibrator portions vibrating in the sub vibration mode are paired. In the composite vibration generating ultrasonic vibrator formed by combining the above main piezoelectric element and one or more pairs of sub piezoelectric elements, the phase angle is shifted at the same frequency as the voltage applied to the piezoelectric element vibrating in the main vibration mode. A frequency varying means for applying a voltage to the auxiliary piezoelectric element vibrating in the auxiliary vibration mode to forcibly change a resonance frequency of the auxiliary piezoelectric element vibrating in the auxiliary vibration mode; A composite vibration generating ultrasonic vibrator, wherein the resonance frequency of the auxiliary vibration mode is made to coincide with the frequency. 5. A plurality of pairs of piezoelectric elements having different vibration modes can be combined to simultaneously vibrate in different vibration modes of a main vibration mode and a sub vibration mode, and a pair of vibrator portions vibrating in the sub vibration mode are paired. In a composite vibration generating ultrasonic vibrator obtained by combining the above main piezoelectric element and one or more pairs of sub piezoelectric elements, the piezoelectric element vibrating both ends of the sub piezoelectric element vibrating in the sub vibration mode in the main vibration mode. A frequency varying means for forcibly changing the resonance frequency of the sub piezoelectric element vibrating in the sub vibration mode by short-circuiting at the same frequency as the applied voltage and at a phase angle shifted; A composite vibration generating ultrasonic vibrator, wherein the resonance frequency of the auxiliary vibration mode is made to coincide with the frequency. 6. A combination of a plurality of pairs of piezoelectric elements having different vibration modes can be simultaneously vibrated in different vibration modes of a main vibration mode and a sub vibration mode, and a pair of vibrator portions vibrating in the sub vibration mode are paired. In a composite vibration generating ultrasonic vibrator obtained by combining the above main piezoelectric element and one or more pairs of sub piezoelectric elements, both ends of the sub piezoelectric element vibrating in the sub vibration mode are short-circuited by a coil, and the inductance of the coil is reduced. A frequency variable unit that forcibly changes the resonance frequency of the piezoelectric element that vibrates in the auxiliary vibration mode by changing,
A composite vibration generating ultrasonic vibrator wherein the resonance frequency of the sub vibration mode is always made to match the resonance frequency of the main vibration mode. 7. A combination of a plurality of pairs of piezoelectric elements having different vibration modes can be simultaneously vibrated in different vibration modes of a main vibration mode and a sub vibration mode, and a pair of vibrator portions vibrating in the sub vibration mode are paired. In the composite vibration generating ultrasonic vibrator formed by combining the above main piezoelectric element and one or more pairs of sub piezoelectric elements, the phase angle is shifted at the same frequency as the voltage applied to the piezoelectric element vibrating in the main vibration mode. A frequency variable means for applying a voltage to the sub-piezo element vibrating in the sub-vibration mode to forcibly change a resonance frequency of the sub-piezo element vibrating in the sub-vibration mode, wherein an integer of the main vibration mode is always provided. A composite vibration generating ultrasonic vibrator characterized in that the resonance frequency of the auxiliary vibration mode is made to coincide with twice the resonance frequency. 8. A plurality of pairs of piezoelectric elements having different vibration modes can be combined to simultaneously vibrate in different vibration modes of a main vibration mode and a sub vibration mode, and a pair of vibrator portions vibrating in the sub vibration mode are paired. In a composite vibration generating ultrasonic vibrator obtained by combining the above main piezoelectric element and one or more pairs of sub piezoelectric elements, the piezoelectric element vibrating both ends of the sub piezoelectric element vibrating in the sub vibration mode in the main vibration mode. A frequency varying means for forcibly changing the resonance frequency of the sub-piezoelectric element vibrating in the sub-vibration mode by short-circuiting at the same frequency as the applied voltage and with a phase angle shifted, and an integer of the main vibration mode always. A composite vibration generating ultrasonic vibrator characterized in that the resonance frequency of the auxiliary vibration mode is made to coincide with twice the resonance frequency. 9. A plurality of pairs of piezoelectric elements having different vibration modes can be combined to be simultaneously vibrated in different vibration modes of a main vibration mode and a sub vibration mode, and a pair of vibrator portions vibrating in the sub vibration mode are paired. In a composite vibration generating ultrasonic vibrator obtained by combining the above main piezoelectric element and one or more pairs of sub piezoelectric elements, both ends of the sub piezoelectric element vibrating in the sub vibration mode are short-circuited by a coil, and the inductance of the coil is reduced. A frequency variable unit that forcibly changes the resonance frequency of the piezoelectric element that vibrates in the auxiliary vibration mode by changing,
A composite vibration generating ultrasonic vibrator, wherein the resonance frequency of the sub vibration mode is always equal to the resonance frequency of an integral multiple of the main vibration mode. 10. A structure having variable means for varying a voltage applied to a vibrator vibrating in the main vibration mode, the structure being capable of changing the amplitude of the main vibration mode, and a vibrator vibrating in the sub vibration mode. A structure having variable means for varying the voltage to be applied and capable of changing the amplitude of the sub-vibration mode, wherein the piezoelectric element vibrating in the main vibration mode the phase angle of the piezoelectric element vibrating in the sub-vibration mode The composite vibration generating ultrasonic vibration according to any one of claims 4 to 9, further comprising a control unit that changes a phase of a voltage applied to each of the plurality of vibrations and controls a voltage and a phase applied to each of the plurality of vibrations. Child.