JP3730467B2 - Ultrasonic vibrator and composite vibration generating ultrasonic vibrator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic vibrator or a combined vibration generating ultrasonic vibrator used for performing various types of processing.
[0002]
[Prior art]
Conventionally, in the field of ultrasonic processing where a relatively large power is required, a Langevin type vibrator that can easily obtain a high output is often used as an ultrasonic vibrator. The resonance frequency of the Langevin type vibrator is substantially determined by physical characteristics such as Young's modulus, density, and dimensions of the components constituting the Langevin type vibrator, but exhibits a fairly sharp resonance. That is, since the electrical sharpness so-called Q (Quality Factor) is very large, the impedance changes greatly in the vicinity of the resonance frequency, and the impedance and amplitude of the vibrator change greatly only by a slight shift of the driving frequency. Therefore, in order to realize efficient ultrasonic vibration, the resonance frequency of the vibrator must be automatically and accurately tracked.
[0003]
If the drive 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 minute change in the resonance frequency due to a temperature change or a load change cannot be ignored, and a technique for always detecting a change in the resonance frequency of the vibrator and driving it by accurately automatically tracking the frequency is indispensable. Therefore, a PLL (Phase Locked Loop) system or the like has been widely used as an oscillator, which 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.
[0004]
For example, when applying ultrasonic vibration to a field such as plastic processing of metal, a power of several kW or more is often required in the processed portion. In such a case, a method is adopted in which the output powers of a large number of vibrators are combined and taken out as high power.
[0005]
As an example, an ultrasonic power synthesizer 201 is shown in FIG. Excitation vibrators 203 are attached to three surfaces of a power combining vibrator 202 each having a cruciform length and width of ½ wavelength (λ / 2), and a processing horn 204 is attached to the remaining one surface. In the case of the ultrasonic power synthesizer 201, the ultrasonic power synthesized by the three excitation vibrators 203 is obtained from the processing horn 204.
[0006]
However, in this case, it is difficult to obtain an efficient output unless the electrical characteristics such as the resonance frequency of the respective excitation vibrators 203 match. When a plurality of vibrators whose electric characteristics such as resonance frequency do not match are coupled, several spurious responses appear due to different resonance frequencies, and ideal automatic tracking cannot be performed. If it continues to be used in such a state, the necessary ultrasonic power cannot be obtained, or a load is applied only to a specific vibrator, which may damage the vibrator or destroy the oscillation device. Such problems occur.
[0007]
In order to avoid such a phenomenon, at the final stage of manufacturing the vibrator, for example, a method of adjusting the frequency so that the frequencies of the vibrators coincide with each other by truncating the dimensions of the vibrator has been taken. In addition to being complicated, in some cases, each resonant frequency may be shifted again due to a change with time, which is not perfect.
[0008]
In the past, vibrators with various vibration forms have been proposed and put to practical use for the purpose of effective use of ultrasonic vibration, and of course the axial vibration mode that vibrates in the same direction as the existing axial direction. Various types of vibrators using a torsional vibration mode that vibrates in a direction twisting around an axis or a bending vibration mode in which a bending moment acts in a direction perpendicular to the axis have been proposed and used. The “axial vibration mode” here is a longitudinal wave (dense wave), the torsional vibration mode is a transverse wave (shear wave), its vibration propagation mechanism is completely different, and each mode is the same shape and the same material. The speed of sound is different. The flexural vibration mode is also called a bending wave, and the sound speed changes greatly depending on the shape of the vibrating body, which is different from the torsional vibration transverse wave. The wavelength λ at the resonance frequency expressed by the formula λ = V / F (λ: wavelength, V: sound velocity, F: resonance frequency) is also completely different in each vibration mode. Accordingly, when conditions such as load and temperature change between different vibration modes, the change rate of the resonance frequency in each vibration mode also changes.
[0009]
Along with recent advances in industrial technology, the realization of a composite vibration generating ultrasonic transducer that realizes unprecedented vibration modes, especially multiple vibration modes with a single transducer, as attempts to effectively use ultrasonic waves become active. The demand for the vibrator is increasing, and the tip of the vibratorInAn attempt has been made to obtain a further improvement in performance by ultrasonic waves by drawing a complicated vibration locus in two or three dimensions.
[0010]
For example, in the case of a TL composite vibrator that realizes torsional vibration (Totional) that vibrates in the torsional direction and axial vibration (Longitudinal) that vibrates in the axial direction with a single vibrator, the speed of sound in each vibration mode is usually used. Therefore, the resonance frequency is completely different between axial vibration and torsional vibration.
[0011]
However, it is possible to make the resonance frequency of the torsional vibration and the resonance frequency of the axial vibration coincide with each other by designing the shape. In general, the wavelength of torsional vibration is shorter than the wavelength of axial vibration, but the resonance frequency can be matched if the shape of the vibrator is designed and the vibrator is designed to have a wavelength of the least common multiple of each other.
[0012]
In this case, the vibration trajectory at the tip of the vibrator can generate spiral vibration if the voltage phase for driving axial vibration and torsional vibration is the same. As an example, FIG. 13 shows a configuration of a TL type composite vibrator 211 and its vibration distribution diagram. In the design stage of the Langevin type TL type composite vibrator 211, in which the axial oscillating piezoelectric element 214 and the torsional vibrating piezoelectric element 215 are sandwiched between the front horn 212 and the rear horn 213, and are fastened with fastening bolts 216. If the resonance frequencies are made to coincide with each other and a high frequency voltage synchronized with the resonance frequency is applied to each of the piezoelectric elements 214 and 215, axial vibration and torsional vibration can be generated simultaneously.
[0013]
At this time, when the amplitude is taken on the vertical axis, the axial vibration is represented as the axial vibration distribution 217 and the torsional vibration is represented as the torsional vibration distribution 218 as shown in FIG.
[0014]
However, it is very difficult to keep the resonance frequencies consistent with each other in practice. That is, the resonance frequency that changes depending on the temperature change and the load size as well as the wear, regrinding, or replacement of the tools mounted on the vibrators 214 and 215 has a different rate of change depending on the vibration mode. The difference between the resonance frequencies is greatly separated by the change.
[0015]
Furthermore, many attempts have been made to generate elliptical vibration using such a composite vibrator.
[0016]
However, elliptical vibrations can be obtained by driving different vibration modes at the same frequency and adjusting their phases. As already explained, it is very difficult to obtain elliptical vibrations stably for a long time. is there.
[0017]
However, there is an attempt to obtain a stable elliptical vibration using automatic tracking even for a short time, and an example of the basic configuration is shown in FIG. A Langevin type B-L (Bending-Longitudinal) type composite vibrator in which the axial vibration piezoelectric element 214 and the flexural vibration piezoelectric elements 219 and 220 are sandwiched between the front horn 212 and the rear horn 213 and fastened with fastening bolts 216. 221 is formed. Here, the flexural vibration piezoelectric elements 219 and 220 are formed in a semicircular shape by dividing an annular piezoelectric element in which two piezoelectric directions face each other into two.
[0018]
The flexural vibration piezoelectric element 219 is constructed by facing the positive side of the piezoelectric direction (→ represented by ←), and the flexural vibration piezoelectric element 220 is oriented by facing the negative side of the piezoelectric direction (represented by ← →). ) Is configured. 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 flexural vibration can be easily generated. A B-L type composite vibrator 221 is configured in combination with the vibration piezoelectric element 214. The shape of the vibrator is devised at the design stage so that the resonance frequencies of the vibrators coincide with each other. When a high-frequency voltage synchronized with the resonance frequency is applied to each of the piezoelectric elements 219 and 220, axial vibration and flexural vibration are simultaneously generated. Can be generated.
[0019]
Now, the output of the voltage controlled oscillator (VCO) 222 is amplified by the flexural vibration output amplifying circuit 223 and applied to the flexural vibration piezoelectric elements 219 and 220 via the flexural vibration speed detector 224.
[0020]
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 the frequency control voltage V1 and fed back to the voltage controlled oscillator 222. If the resonance frequency deviates, the difference appears in the frequency control voltage V1, and the oscillation frequency of the voltage controlled oscillator 222 is controlled, so that a PLL type automatic tracking circuit that always oscillates stably at the resonance frequency is configured. It is possible to continue stable vibration at.
[0021]
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, shaft vibration is also generated at the same time. Here, if the phase is shifted by the phase controller 225, the operation timings of the flexural vibration and the shaft vibration are also shifted, and a vibration locus of a Lissajous waveform is generated. As shown in FIG. 14, a locus S of elliptical vibration is drawn.
[0022]
However, this can only be realized when the resonance frequencies of both vibration modes are completely the same. If either one is slightly deviated from the resonance frequency, the efficiency of the vibration mode deviated from the resonance frequency is extremely high. As a result, only a small amplitude is obtained, resulting in a substantially linear vibration locus.
[0023]
In the case of the circuit of FIG. 14 shown as an example, the resonance frequency of the flexural vibration is always automatically tracked, so that it is possible to stably vibrate at the resonant frequency. However, the shaft vibration is driven at the resonant frequency of the flexural vibration. It has only been done.
[0024]
Therefore, if the resonance frequency of the axial vibration is shifted for some reason, stable elliptical vibration cannot be obtained. Because the Langevin type resonator has a very sharp resonance, that is, Q (Quality Factor) is very large, even if the resonance frequencies of axial vibration and flexural vibration are matched at the design stage, the conditions such as load and temperature are If it changes, the resonance frequency changes from each other, resulting in a completely different resonance frequency. As a result, the relative phase and relative amplitude shift and the vibration mode cannot be controlled correctly.
[0025]
Therefore, the ultrasonic elliptical vibration in the Langevin type composite vibrator is in the present situation where only a temporary experimental result in the applied research stage has been obtained.
[0026]
In addition to this, a B-T type composite vibrator that realizes bending vibration (Bending) that vibrates in a direction perpendicular to the axis and torsional vibration (Totional) that vibrates in a direction twisting with respect to the axis by one vibrator, and 3 There are also T-B-L type composite vibrators that combine two vibration modes, but in any case, it is practically impossible to satisfy and satisfy each resonance frequency for the same reason.
[0027]
[Problems to be solved by the invention]
As described above, in such a conventional technique, it is difficult to easily match the resonance frequencies of the respective vibrators in a device that obtains a large output by synthesizing a plurality of ultrasonic vibrators and to continuously stabilize them. . In addition, in the case of an ultrasonic transducer that generates composite vibrations, it is a conventional general control technology that detects fluctuations in the resonance frequency inherent to the ultrasonic transducer and drives at a frequency that matches that frequency. Although it is possible to connect each oscillator to a resonant frequency that fluctuates freely in each mode and drive it separately, there is no technology to actively control the resonant frequency of the vibrator in real time, and it is synchronized in each vibration mode It is impossible to perform stable vibration control.
[0028]
That is, when there are a plurality of different resonant elements in one vibrating body, even if each resonant frequency is adjusted at the design stage, it is physically impossible to keep it stable, As a countermeasure, a method of actively controlling the resonance frequency has been desired for many years.
[0029]
Therefore, the present invention applies a signal having a different phase to a part of the piezoelectric element constituting the ultrasonic vibrator, or connects an impedance element to control the value of the resonance frequency of the vibrator. An ultrasonic transducer capable of forcibly controlling the resonance frequency, and even when there are a plurality of different resonance elements in a single vibrating body, the resonance frequency of each can be continuously and stably matched completely. An object is to provide a composite vibration generating ultrasonic transducer.
[0030]
[Means for Solving the Problems]
[0032]
  Claim1The ultrasonic transducer according to the invention is an ultrasonic transducer in which a pair of main piezoelectric elements for axial vibration and a pair of sub piezoelectric elements for axial vibration are combined, and is driven by the pair of main piezoelectric elements. When a voltage is applied to vibrate, both ends of the remaining at least one pair of sub-piezoelectric elements are short-circuited at the same frequency as the voltage applied to the main piezoelectric element at a phase angle shifted to electrically connect the vibrator. The frequency variable means for forcibly changing the detected resonance frequency is provided.
[0033]
  That is,For shaft vibrationAmong a plurality of pairs of piezoelectric elements, the ultrasonic vibrator is short-circuited by short-circuiting the electromotive force generated at both ends of the sub-piezoelectric element at a timing shifted from the main piezoelectric element.Detected electricallyThe resonance frequency can be forcibly controlled by applying a voltage to one or more main piezoelectric elements to vibrate, and the remaining one or more sub piezoelectric elements at the same frequency as the voltage applied to the main piezoelectric element. By short-circuiting both ends of the sub piezoelectric element at the timing of shifting the phase angle, the ultrasonic transducerDetected electricallyIt is possible to forcibly shift the resonance frequency to an arbitrary frequency and perform stable vibration by automatic tracking. As a result, even when a plurality of transducers are driven at the same frequency as in an ultrasonic power synthesizer, by applying the present invention, it is possible to easily achieve a stable operation by matching the frequencies with ease. The problem of change disappears.
[0034]
  Claim2The composite vibration generating ultrasonic transducer according to the invention described above is capable of simultaneously oscillating 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 at a combination of a pair of main piezoelectric elements for axial vibration and a pair of sub piezoelectric elements for axial vibration is vibrated in the main vibration mode. Piezoelectric elementAnd the main piezoelectric element that vibrates in the sub vibration mode, respectively.ApplySame based on signals from the same oscillatorA voltage whose phase angle is shifted at the same frequency as the voltage is applied to the sub-piezoelectric element that vibrates in the sub-vibration mode, and the resonance frequency detected electrically of the sub-piezoelectric element that vibrates in the sub-vibration mode is forced. And a frequency varying means for changing the resonance frequency of the secondary vibration mode to the resonance frequency of the main vibration mode.
[0035]
  Claim3The composite vibration generating ultrasonic transducer according to the invention described above is capable of simultaneously oscillating 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 the composite vibration generating ultrasonic vibrator in which the vibrator portion that vibrates at a combination of a pair of main piezoelectric elements for axial vibration and a pair of sub piezoelectric elements for axial vibration is combined, the vibrator vibrates in the sub vibration mode. Connect both ends of the sub piezoelectric element,Piezoelectric element that vibrates in the main vibration modeAnd the main piezoelectric element that vibrates in the sub vibration mode, respectively.ApplySame based on signals from the same oscillatorFrequency variable means for forcibly changing the resonance frequency detected electrically of the sub-piezoelectric element that vibrates in the sub-vibration mode by short-circuiting at the same frequency as the voltage and shifting the phase angle; The resonance frequency of the secondary vibration mode is made to coincide with the resonance frequency of the vibration mode.
[0036]
  That is, these claims2, 3In the described invention, a plurality of pairs of piezoelectric elements having different vibration modes can be combined and vibrated simultaneously in different vibration modes of the main vibration mode and the sub vibration mode. This is a composite vibration generating ultrasonic transducer that combines one or more main piezoelectric elements for vibration and one or more sub piezoelectric elements for axial vibration. It is different from the resonance frequency that vibrates in the main vibration mode. Sub-piezoelectric element in sub-vibration mode vibrating atabout,Variable frequency handStepThe resonance frequency of the sub-vibration mode is always made to coincide with the resonance frequency of the main vibration mode by changing the resonance frequency that is forcibly electrically detected by using the resonance frequency of the main vibration mode. The frequency and the resonance frequency of the sub-vibration mode are forced to coincide with each other, and a stable composite vibration can be obtained continuously. This broadens the range of applications in processing fields such as cutting and grinding using ultrasonic waves, and provides high quality. Can be expected.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
  The first of the present inventionReference example (part 1)Is explained based on FIG..
[0041]
First, a Langevin formed by sandwiching a pair of main piezoelectric elements 1 for axial vibration and a pair of sub piezoelectric elements 2 for axial vibration between a front horn 3 and a rear horn 4 and tightening them firmly with fastening bolts 5. In the type shaft vibrator 6, the output signal of the voltage controlled oscillator 7 is amplified by the main output amplification circuit 8 for shaft vibration and connected so as to be input to the main piezoelectric element 1 through the vibration speed detector 9. Here, the phase difference between the applied voltage and current is detected by the vibration speed detector 9, and the deviation from the resonance frequency is output as the frequency control voltage V 1 and fed back to the voltage controlled oscillator 7, whereby the PLL automatic tracking circuit 10. Thus, the shaft vibration can continue a stable vibration at the resonance frequency.
[0042]
On the other hand, the output of the voltage controlled oscillator 7 is connected so as to be input to the sub piezoelectric element 2 through the phase controller 11 and the sub output amplification 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 by 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 is freely changed according to the degree of deviation of the phase angle. That is, the resonance frequency of the Langevin type axial vibrator 6 is freely changed. This is because the sub-piezoelectric element 2 that is driven by forcibly changing the phase of the driving voltage vibrates with a combined vector with the vibration phase that is mechanically driven by the main piezoelectric element 1. 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 amplifier circuit 12 for shaft vibration constitute the frequency variable means 13.
[0043]
  Like thisReference exampleAccording to the above, the frequency variable for forcibly changing the resonance frequency of the Langevin type axial vibrator 6 by applying a voltage whose phase angle is shifted at the same frequency as the voltage applied to the main piezoelectric element 1 to the sub piezoelectric element 2. Since the means 13 is provided, it is possible to arbitrarily determine the resonance frequency of the Langevin type axial vibrator 6 only by changing the phase by the variable resistor 14.
[0044]
  Of the present inventionFirst reference example (2)Will be described with reference to FIG. FirstReference example (part 1)Portions that are the same as or correspond to the portions indicated by are denoted by the same reference numerals, and description thereof is also omitted (the following embodiments)And even in the reference exampleThe same).
[0045]
  BookReference exampleIn the Langevin type axial vibrator 20, 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 amplifier circuit 8 for axial vibration, and the vibration speed detector 9 is To the main piezoelectric element 1 for shaft vibration. Similarly, the signal amplified from the oscillator 22 via the voltage-controlled phase controller 23 by the sub-amplification circuit 12 for shaft vibration is input to the sub-piezoelectric element 2 for shaft vibration. The detection signal for the resonance frequency of the Langevin type axial vibrator 20 detected by the vibration speed detector 9 is given to the voltage control type phase controller 23 as the phase control voltage V2 to control the phase angle. The vibration speed detector 9, the voltage control type phase controller 23, and the auxiliary output amplifier circuit 12 for shaft vibration constitute a frequency variable means 24.
[0046]
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, the main piezoelectric element 1 for shaft vibration is driven, the original Langevin type shaft vibration is obtained. A difference signal between the resonance frequency of the child 20 and the driven frequency is output from the vibration speed detector 9 to the voltage control type phase controller 23 as the phase control voltage V2, and this is used as the voltage of the feedback signal as the voltage control type phase controller. 23 phase angle is changed.
[0047]
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, it is assumed that the sound speed of the sub-piezoelectric element 2 itself for apparent vibration has changed. As a result, the resonance frequency of the Langevin type axial vibrator 20 itself changes. Then, when the frequency of the oscillator 22 and the changed resonance frequency of the Langevin type axial vibrator 20 coincide with each other, stable resonance vibration is continued.
[0048]
Here, even if the resonance frequency of the Langevin type axial vibrator 20 changes due to a temperature change or a load change, the difference is controlled by the voltage control type phase controller 23 as the phase control voltage V2 to further change the phase. Thus, the resonance frequency of the Langevin type axial vibrator 20 can be forced to automatically follow the oscillation frequency of the oscillator 22.
[0049]
  In other words, the conventional automatic tracking of ultrasonic vibration has changed the oscillation frequency in accordance with the change of the resonance frequency of the vibrator.Reference exampleAccording to the present invention, a new method of forcibly matching the resonance frequency of the Langevin type axial vibrator 20 with the oscillation frequency of the oscillator 22 is provided. Further, similarly to the method shown in FIG. 3, it is possible to drive a plurality of vibrators stably at the same frequency.
[0050]
  Of the present inventionFirst reference example (Part 3)Is explained based on FIG..
[0051]
  BookReference exampleThe first shown in FIG.Reference example (part 1)The problem of the ultrasonic power synthesizer 201 shown in FIG. 12 is solved by developmentally improving the control method. Excitation vibrators 32a, 32b, and 32c are mounted on the three surfaces of the power combining vibrator 31 each having a cross-shaped length and width of ½ wavelength (λ / 2), and the remaining one surface is a processing horn. In the ultrasonic power synthesizer 34 to which 33 is attached, the three excitation vibrators 32a, 32b and 32c each include a main piezoelectric element 1 for axial vibration and a sub piezoelectric element 2 for axial vibration. ing. The synthesized ultrasonic power can be obtained from the processing horn 33. However, with the conventional means, it is difficult to obtain an efficient output unless the electrical characteristics such as the resonance frequency of each vibrator are matched. .
[0052]
  This point, bookReference exampleThen, the output signal of the voltage controlled oscillator 7 is amplified by the main output amplifying circuit 8 for axial vibration and applied to the main piezoelectric element 1 for axial vibration of the first excitation vibrator 32a via the vibration speed detector 9a. To do. Here, the phase difference between the applied voltage and current is detected by the vibration speed detector 9a, and the deviation from the resonance frequency is output as the frequency control voltage V1 and fed back to the voltage controlled oscillator 7, thereby causing the PLL automatic tracking circuit 10 to operate. Thus, the shaft vibration can continue a stable vibration at the resonance frequency.
[0053]
On the other hand, the output of the voltage controlled oscillator 7 is applied to the sub-piezoelectric element 2 for shaft vibration via the phase controller 11a and the sub-output amplifier circuit 12a for shaft vibration. Here, the phase controller 11 a can freely change the phase angle of the signal of the voltage controlled oscillator 7 by adjusting the variable resistor 14 for phase adjustment. When the variable resistor 14 for phase adjustment is changed in this state, the oscillation frequency of the voltage controlled oscillator 7 is freely changed according to the phase shift, and the resonance frequency of the excitation vibrator 32a is freely changed. It will be.
[0054]
Next, the output of the main output amplification circuit 8 for axial vibration is applied to the main piezoelectric element 1 for axial vibration of the second vibrator 32b for excitation via the second vibration speed detector 9b. Then, the output of the voltage controlled oscillator 7 is amplified by the second axial vibration sub-output amplifier circuit 12b via the voltage controlled phase controller 11b, and the second vibration vibrator 32b is also used for the axial vibration. To the secondary piezoelectric element 2. The third excitation vibrator 32c has the same circuit configuration as that of the second excitation vibrator 32b (shown with a suffix “c”). Here, the operation of the first excitation vibrator 32a has been described with reference to FIG.
[0055]
In the case of the second excitation vibrator 32b, the voltage applied to the axial vibration main piezoelectric element 1 is the same as the voltage applied to the axial vibration main piezoelectric element 1 of the first excitation vibrator 32a. . Therefore, when a signal deviating from the original resonance frequency is added, the phase control voltage V2b corresponding to the deviation is output from the vibration speed detector 9b, and the voltage control type phase controller 11b uses the signal for the frequency deviation. The phase angle of the voltage controlled oscillator 7 is changed and amplified by the second axial vibration sub-output amplifier circuit 12b to drive the axial vibration sub-piezoelectric element 2 of the second excitation vibrator 32b to resonate. Is forcibly changed and stabilized at a frequency that matches the first vibration frequency.
[0056]
The third excitation vibrator 32c operates on the same principle, and therefore, the three excitation vibrators 32a, 32b, and 32c vibrate at the same frequency. If multiple resonators that do not match the electrical characteristics such as the resonance frequency are combined, several spurious responses will appear due to the difference in the resonance frequencies, making ideal automatic tracking impossible. If you continue to use it in such a state, you will not be able to obtain the necessary ultrasonic power, or only a specific vibrator will be burdened and damaged, or the oscillator will be destroyed. Such problems occur.
[0057]
  In order to avoid such a phenomenon, at the final stage of manufacturing the vibrator, for example, a method of adjusting the frequency of the vibrator to be the same by cutting the dimensions of the vibrator has been adopted.Reference exampleBy using this countermeasure, it is possible to easily achieve an efficient and stable operation by easily matching the frequencies without specially adjusting the shape of the vibrator, and the problem of change with time is eliminated.
[0058]
  First of the present inventiononeThe embodiment will be described with reference to FIG. This embodiment claims1This corresponds to the described invention.
[0059]
In the Langevin type axial vibrator 40 of the present embodiment, 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 amplifier circuit 8 for axial vibration, and the vibration speed The detector 9 is connected so as to be applied to the main piezoelectric element 1 for axial vibration. Similarly, a signal from the oscillator 22 is connected via the voltage control type phase controller 23 so as to be applied to the sub-piezoelectric element 2 for axial vibration via the short circuit 41 and the conjugate matching coil 42. The inductance of the conjugate matching coil 42 is set to a value that can be conjugate with the braking capacity of the auxiliary piezoelectric element 2 for axial vibration. The short circuit 41 includes a coupling transformer 43, a capacitor 44, two flywheel diodes 45a and 45b, two FETs 46a and 46b, and two inverting amplifiers 47a and 47b. In this short circuit 41, two FETs 46a and 46b are alternately turned on by two inverting amplifiers 47a and 47b. If a DC voltage is applied to the coil neutral point 0 on the secondary side of the coupling transformer 43, push-pull Although an amplifier circuit that has been widely known as a circuit is conventionally used, in the present embodiment, a voltage is not 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 speed detector 9, phase controller 23, short circuit 41 and conjugate matching coil 42 constitute frequency variable means 48.
[0060]
In such a circuit configuration, when a signal of an arbitrary frequency is driven by the oscillator 22 via the main output amplification circuit 8 for shaft vibration and the vibration speed detector 9, the main piezoelectric element 1 for shaft vibration is driven, A difference signal between the resonance frequency and the driven frequency is output from the vibration speed detector 9 as the phase control voltage V2, and the phase angle of the voltage control type phase controller 23 is changed 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 with a signal applied to the main piezoelectric element 1 for axial 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 the piezoelectric effect due to vibration. The piezoelectric element has a reversible relationship between deformation and voltage, and has a piezoelectric effect of deforming when a voltage is applied and generating a voltage when deformed.
[0061]
  Claim1In the present embodiment corresponding to the described invention, the generated voltage is used. A voltage generated in the auxiliary piezoelectric element 2 for axial vibration is applied to the short circuit 41 via the conjugate matching coil 42, thereby inducing a voltage on the secondary side of the coupling transformer 43. On the other hand, the two FETs 46a and 46b are repeatedly turned on and off, and 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. The resonance frequency of the vibrator is forcibly changed by changing the phase shift level, that is, the phase angle. Here, the inventor has previously found that the resonance frequency of the vibrator is greatly different between an open state in which nothing is connected to the sub-piezoelectric element 2 for axial vibration and a state in which the sub piezoelectric element 2 is short-circuited to the ground. This is presumably because the sound velocity changes when the impedance of the piezoelectric element is different. As a means for continuously changing the resonance frequency by utilizing this phenomenon, a frequency variable means 48 for continuously changing the resonance frequency of the vibrator by short-circuiting the phase angle continuously is realized. It is.
[0062]
In such a configuration, when a signal of an arbitrary frequency is driven by the oscillator 22 via the main output amplifier circuit 8 for shaft vibration and the vibration speed detector 9, the main piezoelectric element 1 for shaft vibration is driven, the resonance of the original vibrator. A signal proportional to the difference between the frequency and the driven frequency is output from the vibration speed detector 9 as the phase control voltage V2, and the phase angle (phase difference) of the voltage control type phase controller 23 is changed using this as the feedback signal voltage. . If the phase angle of the short circuit of the sub-piezoelectric element 2 for axial vibration deviates greatly from the signal applied to the main piezoelectric element 1 for axial vibration, the speed of sound of the main piezoelectric element 1 itself for axial vibration has changed forcibly. As a result of this phenomenon, the resonance frequency of the vibrator itself changes. Then, when the drive frequency of the oscillator 22 and the changed resonance frequency of the vibrator coincide with each other, stable resonance vibration is continued. Here, even if the resonance frequency of the vibrator changes due to a temperature change or load fluctuation, the difference is controlled as the phase control voltage V2, and the voltage control type phase controller 23 is controlled to forcibly change the phase. It becomes possible to automatically adjust the resonance frequency of the vibrator to the oscillation frequency of the oscillator 22.
[0063]
  That is, in the conventional automatic vibration tracking, the oscillation frequency is changed in accordance with the change in the resonance frequency of the vibrator.Reference examplesAs in the case of, by providing the frequency varying means 48, the resonance frequency of the vibrator can be forcibly matched with the oscillation frequency of the oscillator 22.
[0064]
  Of the present inventionFirst reference example (4)Is explained based on FIG. 5 and FIG..
[0065]
BookReference exampleIn the Langevin type axial vibrator 50, the signal of the oscillator 22, which 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 vibration of the shaft, and is passed through the vibration speed detector 9. The main piezoelectric element 1 for axial vibration is connected so as to be applied. The vibration speed detector 9 generates an inductance control voltage V3 which is a signal corresponding to the deviation between the resonance frequency of the vibrator and the driven frequency. The sub-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. The 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 driven frequency detected by the vibration speed detector 9 is given to the inductance variable circuit 52 as an inductance control voltage V3 to control the inductance.
[0066]
FIG. 6 shows a detailed circuit example of the inductance variable circuit 52. The variable coil 54 includes a variable coil primary side 54a and a variable coil secondary side 54b, and terminals A and B of the inductance variable circuit 52 coincide with terminals A and B of the variable coil primary side 54a. One terminal of the variable coil secondary side 54 b 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 detection resistor 61, and an operational amplifier 62. An inductance control voltage V3 is applied to the + input of the operational amplifier 62, and a DC stabilization current corresponding to the voltage is applied to the variable coil secondary. It is configured to flow through side 54b.
[0067]
Note that the high frequency voltage of the ultrasonic frequency induced in the variable coil secondary side 54 b 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. As a result, a DC magnetic field is superimposed on the core of the variable coil 54, and the inductance of the variable coil primary side 54b is continuously changed according to the voltage level of the inductance control voltage V3 depending on the strength of the DC magnetic field. Will be.
[0068]
In such a circuit configuration, when a signal of an arbitrary frequency from the oscillator 22 drives the shaft vibration main piezoelectric element 1 via the shaft vibration output amplifier circuit 51 and the vibration speed detector 9, the signal of the oscillator 22 is supported. The vibrator vibrates at the frequency. At the same time, a high-frequency voltage synchronized with the vibration frequency is generated in the sub-piezoelectric element 2 for shaft vibration by the piezoelectric effect due to vibration, and flows to the ground through the inductance variable circuit 52. Here, when the inductance of the inductance variable circuit 52 changes, the resonance frequency of the vibrator also changes. This is because the impedance of the sub-piezoelectric element 2 for axial vibration changes as viewed from the main piezoelectric element 1 for axial vibration, thereby changing the sound velocity of the sub-piezoelectric element 2 for axial vibration, and as a result, the resonance frequency of the vibrator. Is presumed to have been changed.
[0069]
Here, a signal proportional to the deviation between the resonance frequency of the original vibrator and the driven frequency is output from the vibration speed detector 9 as the inductance control voltage V3. This is used as the feedback signal voltage of the inductance variable circuit 52. If the inductance is changed, a stable resonance vibration is continued when the frequency of the oscillator 22 and the changed resonance frequency of the vibrator coincide with each other. At this time, even if the resonance frequency of the vibrator changes due to temperature change or load fluctuation, the difference is controlled as the inductance control voltage V3, and the inductance variable circuit 52 is further changed to forcibly resonate the vibrator. It becomes possible to automatically adjust the frequency to the oscillation frequency of the oscillator.
[0070]
  In other words, the conventional automatic tracking of ultrasonic vibration has been such that the oscillation frequency is changed in accordance with the change in the resonance frequency of the vibrator.Reference exampleThen, by providing the frequency variable means 53, the resonance frequency of the vibrator can be forcibly matched with the oscillation frequency of the oscillator 22, as in the case of the above-described embodiments.
[0071]
  First of the present inventiontwoThe embodiment will be described with reference to FIG. This embodiment claims2This corresponds to the described invention.
[0072]
This embodiment is applied to a BL type composite vibrator 70 which is a composite vibration generating ultrasonic vibrator. That is, in addition to the main piezoelectric element 1 for axial vibration and the secondary piezoelectric element 2 for axial vibration, there are provided flexural vibration piezoelectric elements 71A and 71B having different vibration modes. In other words, the flexural vibration piezoelectric elements 71A and 71B, the axial vibration main piezoelectric element 1 and the axial vibration sub piezoelectric element 2 are sandwiched between the front horn 3 and the rear horn 4 and are firmly tightened with the fastening bolts 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 71 </ b> A and 71 </ b> B via the flexural vibration speed detector 73. Generates a mode of 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 as the frequency control voltage V4. If the voltage controlled oscillator 7 is controlled using V4 as a feedback signal, the flexural vibration becomes a PLL type automatic tracking, and the vibration can be continued stably at the resonance frequency.
[0073]
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 flexural vibration is applied. Further, the signal from the voltage controlled oscillator 7 is amplified by the auxiliary output amplifying circuit 12 for axial vibration via the voltage controlled phase controller 23 and then applied to the auxiliary piezoelectric element 2 for axial vibration. Here, the shaft vibration speed detector 74, the voltage control type phase controller 23, and the auxiliary output amplifier circuit 12 constitute a frequency variable means 75 (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 V 2 detected by the shaft vibration speed 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 resonance frequency of the flexural vibration. By controlling the phase angle of the signal applied to the sub-piezoelectric element 2 for shaft vibration as the phase control voltage V2, the signal becomes a feedback signal, and the resonance frequency of the shaft vibration is forcibly matched with the resonance frequency of the flexural vibration. That is, the resonance frequency of the axial 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.
[0074]
  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.3Equivalent to the described invention).
[0075]
Of the present inventionSecond reference exampleIs explained based on FIG..
[0076]
BookReference exampleIs also applied to the BL type composite vibrator 80 which is a composite vibration generating ultrasonic vibrator.
[0077]
TheB in which bending vibration piezoelectric elements 71A and 71B, an axial vibration main piezoelectric element 1 and an axial vibration auxiliary piezoelectric element 2 are sandwiched between a front horn 3 and a rear horn 4 and tightened with fastening bolts 5 In the L-type composite vibrator 80, a signal from the voltage controlled oscillator 7 is amplified by a flexural vibration output amplifier circuit 82 whose amplitude can be controlled by a variable resistor 81 for controlling flexural vibration amplitude, and a flexural vibration speed detector 73 is obtained. Is applied to the piezoelectric elements 71A and 72B for flexural vibration via the sag to generate 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 element as the frequency control voltage V1, and feeds back the frequency control voltage V1. If the voltage controlled oscillator 7 is controlled as a signal, the flexural vibration becomes a PLL type automatic tracking, and the vibration can be continued stably at the resonance frequency.
[0078]
  On the other hand, the amplitude of the signal of the voltage controlled oscillator 7 is controlled by the variable resistor 85 for axial vibration amplitude control via the vibration locus control phase controller 84 whose phase angle can be arbitrarily varied by the variable resistor 83 for phase adjustment. Amplified by a possible shaft vibration output amplification circuit 86 and applied to the main piezoelectric element 1 for shaft vibration via the shaft vibration speed detector 74, and the phase angle is changed at the same frequency as the resonance frequency of the flexural vibration. A signal is applied. Further, the signal from the voltage controlled oscillator 7 is amplified by the shaft output sub-output amplifier circuit 12 through the voltage control type phase controller 23 and applied to the shaft vibration sub-piezoelectric element 2. The phase angle of the voltage control type phase controller 23 is controlled in accordance with the phase control voltage V 2 detected by the shaft vibration speed detector 74. I.e.twoIn contrast to the embodiment, a control means 87 is added by a phase controller 84 for vibration trajectory control and an output amplifier circuit 86 for shaft vibration. That is, bookReference exampleThen, by changing the voltage applied to the flexural vibration (main vibration) mode by the variable resistor 81 for controlling the flexural vibration amplitude, the amplitude of the flexural vibration can be changed, and for controlling the axial vibration amplitude. The control means 87 has a structure capable of changing the amplitude of the axial vibration mode by changing the voltage applied to the axial vibration (sub vibration) mode by the variable resistor 85. By changing the phase and the voltage applied to each phase and controlling the phase, a vibration locus of the Lissajous waveform is generated, and the vibration locus is arbitrarily controlled.
[0079]
  In the case of the composite vibrator 80 having such a structure, the main piezoelectric element 1 for axial vibration is always driven at the resonance frequency of flexural vibration.twoAs in the principle described in the embodiment, a signal proportional to the deviation between the resonance frequency of the shaft vibration and the frequency of the flexural vibration becomes a feedback signal, and the phase of the signal applied to the sub piezoelectric element 2 for shaft vibration as the phase control voltage V2 By controlling, the resonance frequency of the shaft vibration is forcibly matched with the resonance frequency of the flexural vibration, and a stable complex 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.
[0080]
For example, if the mutual phase angle is set to 90 degrees, the tip of the transducer will draw a locus shown by elliptical vibration S1, and if the vibration amplitude of the flexural vibration and the axial vibration are equal, a perfect circular locus can be drawn. It is. Here, by adjusting the variable resistor 81 for controlling the flexural vibration amplitude and the variable resistor 85 for controlling the shaft vibration amplitude, it is possible to draw trajectories of Lissajous waveforms having various ellipticities. Furthermore, 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 realized freely.
[0081]
Of the present inventionThird reference exampleIs explained based on FIG..
[0082]
BookReference exampleThen, 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 are strongly tightened with the fastening bolts 5. A mold composite vibrator 90 is used.
[0083]
Here, the pair of flexural vibration piezoelectric elements 71C and 71C ′ is formed by dividing the annular piezoelectric element, which is aligned so that the piezoelectric directions of each other face each other, into a semi-annular shape. It is configured with the positive side facing each other (→ ←). However, the effect is the same even if the two piezoelectric groups are configured such that the piezoelectric directions face each other (represented by ← →). In this case, if each drive voltage is applied in the opposite phase without using electrodes in common, the other piezoelectric element contracts in a cycle in which one piezoelectric element expands, so that flexural vibration can be easily generated. become. Further, if an in-phase drive voltage is applied to each electrode, each flexural vibration piezoelectric element 71C, 71c 'repeats expansion and contraction in the same cycle, and thus shaft vibration can be generated. Accordingly, by combining the same flexural vibration piezoelectric elements 71C and 71c 'and changing the phase of the drive voltage applied to each, it is possible to generate both axial vibration and flexural vibration.
[0084]
Here, one secondary terminal A of the vibration synthesizing transformer 91 is connected to one terminal A of the flexural vibration piezoelectric element 71C, and the other secondary terminal B of the vibration synthesizing transformer 91 is connected to the other terminal B. If the drive voltage is applied to the neutral point 0 on the secondary side of the vibration synthesizing transformer 91 when connected to the terminal B of the flexural vibration piezoelectric element 71C ′, the flexural vibration piezoelectric elements 71C and 71C ′ have the same driving voltage. Is applied to generate shaft vibration. At the same time, if another drive voltage is applied to the primary side of the vibration synthesizing transformer 91, the opposite phase voltage appears on the terminals A and B on the secondary side of the vibration synthesizing transformer 91. Therefore, the piezoelectric elements 71C and 71C for flexural vibration are applied. It becomes possible to generate a flexural vibration at ′.
[0085]
Therefore, if the vibration synthesizing transformer 91 is used, a BL type composite vibrator 90 with a simplified vibrator structure can be realized.
[0086]
Here, the signal of the voltage controlled oscillator 7 is amplified by a flexural vibration output amplifier circuit 82 whose amplitude can be controlled by the variable resistor 81 for controlling the flexural vibration amplitude, and then the vibration is synthesized via the flexural vibration speed detector 73. The transformer 91 is connected so as to be given. 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 element as a frequency control voltage V1, and uses this frequency control voltage V1 as a feedback signal. If the controlled oscillator 7 is controlled, the flexural vibration becomes a PLL type automatic tracking, and the vibration can be continued stably at the resonance frequency.
[0087]
On the other hand, the amplitude of the signal of the voltage controlled oscillator 7 is controlled by the variable resistor 85 for axial vibration amplitude control via the vibration locus control phase controller 84 whose phase angle can be arbitrarily varied by the variable resistor 83 for phase adjustment. Amplified by a possible shaft vibration output amplifying circuit 86 and connected to be input to a neutral point on the secondary side of the vibration synthesizing transformer 91 via the shaft vibration speed detector 74, and the resonance frequency of the flexural vibration The same signals with different phase angles are applied. Further, the signal from the voltage controlled oscillator 7 is amplified by the shaft output sub-output amplifier circuit 12 through the voltage control type phase controller 23 and applied to the shaft vibration sub-piezoelectric element 2. The phase angle of the voltage control type phase controller 23 is controlled by the phase control voltage V 2 detected by the shaft vibration speed detector 74.
[0088]
BookReference exampleIn the case of the B-L composite vibrator 90 shown in FIG.Second reference exampleIn this case, stable composite vibration can be realized by the same principle as described above, but the flexural vibration piezoelectric elements 71C and 71C 'Second reference exampleThus, the operations of the bending vibration piezoelectric elements 71A and 71B and the axial vibration main piezoelectric element 1 are simultaneously executed. Therefore, if the phase angle is adjusted by the variable resistor 83 for phase adjustment, it is possible to draw an arbitrary Lissajous waveform locus at the tip of the vibrator.
[0089]
For example, if the mutual phase angle is set to 90 degrees, the tip of the transducer will draw a locus shown by elliptical vibration S1, and if the vibration amplitude of the flexural vibration and the axial vibration are equal, a perfect circular locus can be drawn. It is. Here, by adjusting the variable resistor 81 for controlling flexural vibration amplitude and the variable resistor 85 for controlling shaft vibration amplitude, it is possible to draw trajectories of Lissajous waveforms having various ellipticities. Furthermore, 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 realized freely.
[0090]
  First of the present inventionFour reference examples (1)Is explained based on FIG..
[0091]
  BookReference exampleIs applied to the BL type composite vibrator 100 which is a composite vibration generating ultrasonic vibrator. B- which is sandwiched between the front horn 3 and the rear horn 4 with the bending vibration piezoelectric elements 71A and 71B, the axial vibration main piezoelectric element 1 and the axial vibration sub piezoelectric element 2 and tightened firmly with the fastening bolt 5. In the L-type composite vibrator 100, the signal of the voltage controlled oscillator 7 is divided by an integer by the frequency dividing circuit 101, and then the flexural vibration whose amplitude can be controlled by the variable resistor 81 for controlling the flexural vibration amplitude. Amplified by the output amplifier circuit 82 and applied to the flexural vibration piezoelectric elements 71A and 71B via the flexural vibration speed detector 73 to generate flexural vibration.
[0092]
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 element as the frequency control voltage V1, and feeds back the frequency control voltage V1. If the voltage controlled oscillator 7 is controlled as a signal, the flexural vibration becomes a PLL type automatic tracking, and the vibration can be continued stably at the resonance frequency.
[0093]
On the other hand, the signal of the voltage controlled oscillator 7 is amplified by the shaft vibration output amplifying circuit 86 capable of controlling the amplitude by the variable resistor 85 for controlling the shaft vibration amplitude, and the shaft vibration main detector for shaft vibration is passed through the shaft vibration speed detector 74. By inputting to the piezoelectric element 1, a signal having a frequency that is an integral multiple of the resonance frequency of the flexural vibration is applied. Further, the signal from the voltage controlled oscillator 7 is amplified by the shaft output sub-output amplifier circuit 12 through the voltage control type phase controller 23 and applied to the shaft vibration sub-piezoelectric element 2. The phase angle of the voltage control type phase controller 23 is controlled by the phase control voltage V 2 detected by the shaft vibration speed detector 74.
[0094]
In the case of the B-L type composite vibrator 100 having such a configuration, the main piezoelectric element 1 for shaft vibration is always driven at a frequency that is an integral multiple of the resonance frequency of flexural vibration. A signal proportional to the deviation between the frequency and a frequency that is an integral multiple of the flexural vibration becomes a feedback signal, and the phase frequency of the signal applied to the sub piezoelectric element 2 for axial vibration as the phase control voltage V2 is controlled, so that the resonance frequency of the axial vibration is The frequency is forced to be an integral multiple of the resonance frequency of the flexural vibration, and a stable composite vibration can be realized.
[0095]
For example, when the frequency dividing ratio of the frequency dividing circuit 101 is halved, a locus of a Lissajous waveform such as an 8-shaped vibration S3 can be drawn at the tip portion of the vibrator. Then, by adjusting the variable resistor 81 for controlling the flexural vibration amplitude and the variable resistor 85 for controlling the shaft vibration amplitude, it is possible to freely draw trajectories having different aspect ratios as the amplitude of the figure-8 vibration S3. It is done.
[0096]
  BookReference exampleIn the above, the frequency variable means 75 corresponding to the frequency variable means 24 is used, but the frequency variable means corresponding to the frequency variable means 13, 48 or 53 may be used.Yes.
[0097]
  Of the present inventionFourth reference example (2)Is explained based on FIG..
[0098]
TheB in which bending vibration piezoelectric elements 71A and 71B, axial vibration main piezoelectric element 1 and axial vibration sub piezoelectric element 2 are sandwiched between front horn 3 and rear horn 4 and tightened with fastening bolt 5 In the L-type composite vibrator 110, the signal of the voltage controlled oscillator 7 is divided by an integer by the frequency dividing circuit 101, and the amplitude is controlled by the variable resistor 81 for controlling the flexural vibration amplitude. Amplified by the output amplifying circuit 82 and applied to the flexural vibration piezoelectric elements 71A and 71B via the flexural vibration speed detector 73 to generate flexural vibration.
[0099]
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 element as the frequency control voltage V1, and feeds back the frequency control voltage V1. If the voltage controlled oscillator 7 is controlled as a signal, the flexural vibration becomes a PLL type automatic tracking, and the vibration can be continued stably at the resonance frequency.
[0100]
On the other hand, the amplitude of the signal of the voltage controlled oscillator 7 is controlled by the variable resistor 85 for axial vibration amplitude control via the vibration locus control phase controller 84 whose phase angle can be arbitrarily varied by the variable resistor 83 for phase adjustment. Amplified by a possible shaft vibration output amplification circuit 86 and applied to the main piezoelectric element 1 for shaft vibration via the shaft vibration speed detector 74, and the phase angle is changed at a frequency that is an integral multiple of the resonance frequency of flexural vibration. A signal is applied. Further, the signal from the voltage controlled oscillator 7 is amplified by the shaft output sub-output amplifier circuit 12 through the voltage control type phase controller 23 and applied to the shaft vibration sub-piezoelectric element 2. The phase angle of the voltage control type phase controller 23 is controlled by the phase control voltage V 2 detected by the shaft vibration speed detector 74.
[0101]
  That is,Fourth reference example (part 1)The control means 87 by the vibration locus control phase controller 84 and the shaft vibration output amplifier circuit 86 is added. That is, bookReference exampleThen, by changing the voltage applied to the flexural vibration (main vibration) mode by the variable resistor 81 for controlling the flexural vibration amplitude, the amplitude of the flexural vibration can be changed, and for controlling the axial vibration amplitude. The control means 87 has a structure capable of changing the amplitude of the axial vibration mode by changing the voltage applied to the axial vibration (sub vibration) mode by the variable resistor 85. By changing the phase and the voltage applied to each phase and controlling the phase, a vibration locus of the Lissajous waveform is generated, and the vibration locus is arbitrarily controlled.
[0102]
In the case of the composite vibrator 110 having such a configuration, the main piezoelectric element 1 for shaft vibration is always driven at a frequency that is an integral multiple of the resonance frequency of flexural vibration. The signal proportional to the deviation from the integral multiple of the frequency becomes a feedback signal, and the phase of the signal applied to the sub-piezoelectric element 2 for shaft vibration is controlled as the phase control voltage V2, thereby forcibly bending the resonance frequency of the shaft vibration. Therefore, a stable complex vibration can be realized.
[0103]
Here, if the frequency dividing ratio of the frequency dividing circuit 101 is set to ½ and the phase angle is adjusted by the variable resistor 83 for phase adjustment, the locus of an arbitrary Lissajous waveform can be drawn. For example, if the mutual phase angle is set to 45 degrees, the transducer tip portion will draw a locus 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 transducer tip end The part 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 flexural vibration amplitude and the variable resistor 85 for controlling the shaft vibration amplitude, it is possible to draw the locus of the Lissajous waveform having various aspect ratios. . Furthermore, when the frequency dividing ratio of the frequency dividing circuit 101 is set to 1/3, a vibration locus such as a Lissajous waveform S6 having a phase shift can be realized. As described above, various vibration trajectories can be obtained by changing the settings of the frequency division ratio, the phase angle, and the amplitude.
[0104]
【The invention's effect】
[0105]
  Claim1According to the described invention, a voltage is applied to one or more main piezoelectric elements for axial vibration to vibrate, and the remaining one or more sub piezoelectric elements for axial vibration have the same frequency as the voltage applied to the main piezoelectric element. Since both ends of the sub-piezoelectric element are short-circuited at the timing of shifting the phase angle, the resonance frequency detected by the ultrasonic transducer is forcibly shifted to an arbitrary frequency and stable vibration is achieved by automatic tracking. For example, even when multiple transducers are driven at the same frequency, such as an ultrasonic power synthesizer, the frequency can be easily matched to achieve an efficient and stable operation. Can be eliminated.
[0106]
  Claim2, 3According to the described 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. This is a composite vibration generating ultrasonic transducer that is a combination of one or more main piezoelectric elements for axial vibration and one or more sub piezoelectric elements for axial vibration. Sub-piezoelectric element in sub-vibration mode vibrating in modeAroundWave number variable handStepAs a result, it is possible to obtain a consistent composite vibration continuously, expanding the application range in machining fields such as cutting and grinding using ultrasonic waves, and expecting high-quality machining. .
[Brief description of the drawings]
FIG. 1 shows the first of the present invention.Reference example (part 1)It is a block diagram of the ultrasonic transducer | vibrator which shows.
FIG. 2 of the present inventionFirst reference example (2)It is a block diagram of the ultrasonic transducer | vibrator which shows.
FIG. 3 of the present inventionFirst reference example (Part 3)It is a block diagram of the ultrasonic transducer | vibrator which shows.
FIG. 4 shows the first aspect of the present invention.oneIt is a block diagram of the ultrasonic transducer | vibrator which shows this embodiment.
FIG. 5 shows the present invention.First reference example (4)It is a block diagram of the ultrasonic transducer | vibrator which shows.
FIG. 6 is a circuit diagram showing a configuration example of the inductance variable circuit.
FIG. 7 is a configuration diagram of a composite vibrator showing a second embodiment of the present invention.
FIG. 8 is a configuration diagram of a composite vibrator showing a second reference example of the present invention.
FIG. 9 is a configuration diagram of a composite vibrator showing a third reference example of the present invention.
FIG. 10 shows the present invention.Fourth reference example (part 1)FIG.
FIG. 11 shows the present invention.Fourth reference example (2)FIG.
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 vibrator.
[Explanation 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

Claims (3)

In an ultrasonic transducer in which a pair of main piezoelectric elements for axial vibration and a pair of sub piezoelectric elements for axial vibration are combined,
When a drive voltage is applied to one or more pairs of main piezoelectric elements to vibrate, both ends of the remaining at least one pair of sub-piezoelectric elements are shifted in phase angle at the same frequency as the voltage applied to the main piezoelectric elements. An ultrasonic transducer comprising frequency variable means for forcibly changing a resonance frequency detected electrically by short-circuiting. 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, and the vibrator portions that vibrate in the sub vibration mode have at least one pair for axial vibration. In the composite vibration generating ultrasonic transducer formed by combining the main piezoelectric element and a pair of auxiliary piezoelectric elements for axial vibration,
The piezoelectric element and the said main piezoelectric element into a voltage the secondary vibration mode by shifting the phase angle at the same voltage and same frequency based on a signal from the same oscillator to be applied respectively to vibrate in secondary vibration mode vibrates in the main vibration modes And a frequency variable means for forcibly changing a resonance frequency electrically detected by the sub-piezoelectric element that vibrates in the sub-vibration mode by applying to the sub-piezoelectric element vibrating at A composite vibration-generating ultrasonic transducer characterized in that the resonance frequency of the sub-vibration mode coincides with a frequency. 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, and the vibrator portions that vibrate in the sub vibration mode have at least one pair for axial vibration. In the composite vibration generating ultrasonic transducer formed by combining the main piezoelectric element and a pair of auxiliary piezoelectric elements for axial vibration,
The same voltage based both ends of the sub-piezoelectric element which vibrates at the secondary vibration mode, a signal from the same oscillator to be applied to each of the main piezoelectric element which vibrates by the piezoelectric element and the secondary vibration mode vibrates in the primary vibration mode And a frequency variable means for forcibly changing the resonance frequency detected electrically of the sub-piezoelectric element that vibrates in the sub-vibration mode by short-circuiting at the same frequency and with the phase angle shifted, and always changing the main vibration A composite vibration generating ultrasonic transducer characterized in that the resonance frequency of the sub vibration mode is made to coincide with the resonance frequency of the mode.

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