JP2020073275A - Oscillation excitation method for langevin ultrasonic transducer, and ultrasonic machining method for material to be machined - Google Patents

Abstract

To provide a method for exciting ultrasonic oscillation with reciprocating motion in a new oscillation mode by using a Langevin ultrasonic transducer, an ultrasonic machining method and an ultrasonic transmission method using the new ultrasonic oscillation.SOLUTION: A method includes: preparing a Langevin ultrasonic transducer comprising a metal block, another metal block including a supporting frame protruding in a ring shape on its side surface, and polarized piezoelectric elements fixed between these metal blocks; connecting the ultrasonic transducer to a base via the supporting frame, and supporting the ultrasonic transducer on the base in a restrained state; applying, to the piezoelectric elements of the ultrasonic transducer, voltage having predetermined frequency to cause the ultrasonic transducer to excite ultrasonic oscillation with reciprocating motion which has no oscillation node inside the ultrasonic transducer in a direction perpendicular to plane surfaces of the piezoelectric elements. And an ultrasonic machining method and an ultrasonic transmission method using the method to excite oscillation of the ultrasonic transducer are provided.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a vibration excitation method for a Langevin type ultrasonic transducer, and more particularly to a novel excitation method for ultrasonic vibration of a vibration mode. The present invention also relates to an ultrasonic machining method and an ultrasonic transmission method that utilize ultrasonic vibration of a novel vibration mode of a Langevin type ultrasonic vibrator.

  Ultrasonic transducers that use a piezoelectric element as an ultrasonic wave generation source are known to have various configurations. As a typical configuration, a pair of metal blocks and a polarization fixed between these metal blocks are known. A Langevin-type ultrasonic transducer composed of a processed piezoelectric element is known. Among them, the bolted Langevin type ultrasonic vibrator, which has a structure in which a polarized piezoelectric element is connected with a bolt between a pair of metal blocks and clamped and fixed at high pressure, is capable of generating high-energy ultrasonic vibration. The use in ultrasonic processing, which is attached to a tool for performing cutting, plastic working, and abrasive processing of various materials, is being considered. Furthermore, for various ultrasonic transducers, ultrasonic vibration generated by the ultrasonic transducers is transmitted through a diaphragm or vibrating means to perform ultrasonic cleaning, metal bonding, plastic welding, ultrasonic mist. Consideration of ultrasonic wave processing such as emulsification, emulsification and dispersion, as well as underwater acoustic equipment (sonar) such as fish finder, ultrasonic flaw detector, medical echo diagnostic device, and communication application equipment such as flowmeter. Have been used in many fields.

  The configuration of various ultrasonic transducers including the bolted Langevin type ultrasonic transducer is already known, but as a precaution, an example of the configuration of a typical bolted Langevin type ultrasonic transducer and its usage form A brief description is given below with reference to the accompanying FIGS. 1 and 2.

  FIG. 1 is a diagram showing an example of a typical structure of a bolted Langevin type ultrasonic transducer. The bolted Langevin ultrasonic transducer 1 includes a polarized piezoelectric element (eg, a piezoelectric ceramic plate such as PZT) 3 sandwiched between a pair of metal blocks 2a and 2b, and bolts 4 are used to block the metal blocks 2a and 2b. Have a structure in which they are fastened to each other. In FIG. 1, the arrow written on the piezoelectric element indicates the polarization direction. In addition, the piezoelectric element 3 is connected with electrode pieces (usually using an electrode piece such as phosphor bronze) 5a and 5b used as terminals for applying electric energy.

  FIG. 2 is a diagram showing a configuration example of an ultrasonic grinding apparatus (polishing machine) using a bolted Langevin type ultrasonic vibrator as an ultrasonic vibration source. In FIG. 2, an ultrasonic grinding apparatus 10 accommodates an ultrasonic vibrator 1 having a polishing tool 13 connected to a lower end portion thereof via a horn 12 in a housing 11. It is rotatably supported by the bearing 14. The rotation of the ultrasonic transducer 1 is driven by an AC spindle motor 16 connected to the servo unit 15. In the apparatus of FIG. 2, the electric energy for ultrasonic vibration of the ultrasonic vibrator 1 is a contact type power supply including a carbon brush and a slip ring connected to an electric energy supply source 17 provided outside. It is supplied via the device 18.

  The effects expected by applying ultrasonic vibration to various tools in the ultrasonic processing equipment are reduction of electric energy necessary for processing work by the tool and improvement of processing accuracy, etc. The expected effects have not been sufficiently obtained with the ultrasonic processing apparatus that has been used for the above-mentioned processing work. For this reason, it cannot be said that the ultrasonic processing apparatus has been sufficiently spread at the present time. Therefore, in order to promote the further popularization of ultrasonic machining, the amount of electrical energy required to excite the vibration of the ultrasonic transducer during the execution of ultrasonic machining work is reduced, and sufficient machining accuracy is improved. It is necessary to improve so that

  The inventor of the present invention has hitherto devised an improved invention of various ultrasonic vibrators, which can be expected to improve the processing accuracy commensurate with the amount of electric energy required to excite the vibration of the ultrasonic vibrator, and has filed a patent application. I went. For example, among these improved inventions, the invention disclosed in Patent Document 1 can be mentioned as a recent invention.

  In Patent Document 1, a vibration complex of a tool and an ultrasonic vibration body is supported with high stability, and a support body (fixed support body) of the vibration complex of ultrasonic energy generated in the ultrasonic vibration body. As a supporting structure that enables application of vibration energy to the tool with high efficiency by suppressing leakage to the low level, a flange is attached to the ultrasonic vibrating body equipped with the tool, and one side of the flange is attached. A support structure that engages and supports by contacting the flange support surface formed on a separately prepared fixed body under stress (however, the flange of the ultrasonic vibrator is not joined to the flange support surface of the fixed body. The flange of the ultrasonic vibrating body that is not supported by the supporting surface of the fixed body is engaged with the supporting surface of the fixed body and vibrates ultrasonically in the thickness direction of the flange when the ultrasonic vibrating body is a vibrating body. ) Disclosed It has been.

International publication WO 2014/017460 A1

  The ultrasonic processing apparatus using the new ultrasonic vibrator supporting structure described in Patent Document 1 solves a number of problems of the ultrasonic processing apparatus using the ultrasonic vibrator having the conventionally known structure. It was observed. However, also in the ultrasonic processing apparatus using the support structure of the ultrasonic vibrator described in Patent Document 1, it is possible to reduce the required amount of electric energy and to improve the processing accuracy at a practically sufficiently satisfactory level. Not not.

  Therefore, an object of the present invention is to provide a structure of an ultrasonic transducer suitable for ultrasonic machining which can realize both reduction of the required amount of electric energy at a practically sufficiently satisfactory level and improvement of machining accuracy. An object of the present invention is to provide a method for exciting vibration of an ultrasonic vibrator.

  The inventor of the present invention once again examined the mechanism of ultrasonic vibration generation in the ultrasonic vibrator for the purpose of improving the support structure of the ultrasonic vibrator described in Patent Document 1. Then, at the time of the examination, a supporting structure shown in FIG. 3 was devised as a model of a structure for firmly supporting the ultrasonic transducer. That is, in the support structure of FIG. 3, when the bolted Langevin type ultrasonic transducer 1 is assembled, first, an annular shape is formed around the upper end portion of the metal block (generally called “front mass”) 2b arranged on the front side. The support frame 6 is formed integrally with a metal block, and the flat plate-shaped piezoelectric element 3 that has been polarized is bolted between the front mass 2b and the metal block (generally called "rear mass") 2a arranged on the rear side. It was tightened and fixed at 4. Then, after the bolted Langevin type ultrasonic transducer 1 configured as described above is prepared, the edge portion of the annular support frame body 6 is provided with a housing 11 provided with a male screw (this housing itself does not show a support structure body). (Which is connected to a base, which is fixed), and a nut 7 having a female screw are engaged with each other by a fitting structure, and fixedly fixed. The bolted Langevin type ultrasonic transducer 1 is supplied with electric energy to the piezoelectric element 3 through a hole formed in the housing 11 at a predetermined frequency from an ultrasonic oscillation circuit 8 provided outside the housing. The voltage which it has was applied.

  Then, as an ultrasonic transducer supported and fixed by the support structure shown in FIG. 3, in order to observe its vibration characteristics through experiments, a bolted Langevin type ultrasonic vibration having a shape and size (unit: mm) shown in FIG. 4 was used. Child 1 was produced. In the bolted Langevin type ultrasonic transducer 1 of FIG. 4, polarization-processed flat plate-shaped piezoelectric elements (PZT piezoelectric elements) 3a and 3b are made of stainless steel like the rear mass 2a. In addition, it is arranged between the integrally molded front mass 2b and the front mass 2b, and is fixed by the bolt 4 also integrally molded with the front mass 2b. Then, a tapered concave portion for fitting a collet with a tool attached is formed in the lower portion of the front mass 2b.

  In order to observe the ultrasonic vibration characteristics of the bolted Langevin type ultrasonic vibrator having the shape and size shown in Fig. 4 by an experiment, first, an impedance analyzer was used and the ultrasonic vibrator was not restrained. The frequency characteristic was measured, and then the frequency characteristic was similarly measured with the same ultrasonic transducer supported and fixed (restricted) by the support structure shown in FIG. FIG. 5 shows the admittance curve showing the frequency characteristic of the bolted Langevin type ultrasonic transducer in the unconstrained state of FIG. 4, and the admittance curve showing the frequency characteristic of the bolted Langevin type ultrasonic transducer restrained by the support structure shown in FIG. 6 shows.

  As is clear from the admittance curve in FIG. 5, in the bolted Langevin type ultrasonic transducer to be measured, one admittance peak appears at a frequency position of 42.125 KHz in the unrestrained state. The frequency of the admittance peak (42.125 KHz) is understood to be the resonance frequency that excites the first-order longitudinal vibration of the ultrasonic transducer of FIG. 4 in the unrestrained state.

  On the other hand, in the admittance curve of the bolted Langevin type ultrasonic transducer in the restrained state shown in FIG. 6, one at a frequency (44.375 KHz) close to the resonance frequency for exciting the longitudinal primary vibration seen in the admittance curve of FIG. It was found that an admittance peak appears, and further, an admittance peak slightly smaller than the admittance peak at the resonance frequency appears at a frequency position of 24.250 KHz in a region on the lower frequency side than the frequency of the admittance peak.

  The existence of the two admittance peaks shown by the admittance curve in FIG. 6 means that the ultrasonic vibration of the bolted Langevin type ultrasonic transducer to be measured can be excited at any frequency. To be taken. That is, both of these two frequencies are considered to correspond to the resonance frequency that enables the excitation of ultrasonic vibrations. The present inventor pays attention to the existence of the admittance peaks appearing at these two different frequency positions, and the voltage having frequencies close to the two resonance frequencies found from the admittance curve of FIG. 6 is restrained as shown in FIG. The ultrasonic vibration was excited by applying it to the Langevin type ultrasonic vibrator of bolting shown in FIG. 4 under the conditions, and the vertical vibration displacement amount of the lower end surface of the front mass 2b under vibration was measured by a laser Doppler vibrometer. ..

  According to the measurement result of the vertical vibration displacement amount of the lower end surface of the front mass 2b using the laser Doppler vibrometer, the frequency (43) which is close to the frequency of the admittance peak on the relatively high frequency side in FIG. The amount of vibration displacement of the lower end face of the front mass 2b of the ultrasonic transducer excited by ultrasonic wave (so-called longitudinal primary vibration) by applying a voltage of about 0.86 KHz is about 33 μm. It was found that the required power was about 3.5W. On the other hand, the front mass 2b of the ultrasonic transducer in which ultrasonic vibration is excited by applying a voltage (23.64 KHz) having a frequency close to the frequency of the admittance peak on the relatively small low frequency side in FIG. Although the vibration displacement amount of the lower end surface of was about 30 μm, the power required for the ultrasonic vibration was found to be significantly reduced to about 0.5 W.

  Therefore, the ultrasonic vibration (longitudinal primary vibration) that appears in the ultrasonic transducer due to the voltage application of the frequency corresponding to the relatively large admittance peak that appears on the high frequency side of the admittance curve in FIG. The ultrasonic vibrations that appear in the ultrasonic transducer when a voltage of a frequency corresponding to a small admittance peak is applied are almost the same in terms of the amount of vertical vibration displacement, but ultrasonic vibrations of approximately the same amount are used. The power required to excite the latter is about 1/7 (0.5 W / 3.5 W) of the former, that is, the bolted Langevin ultrasonic transducer having the configuration shown in FIG. The power required to excite ultrasonic vibrations in the state of being supported and constrained by using the support structure shown in Fig. 2 is the latter, which is vibration by applying a voltage of the resonance frequency on the low frequency side. It, as compared to the case of using the vibration of an applied voltage of the resonant frequency of the former high-frequency side (the longitudinal primary vibration), was found to be significantly reduced.

  Then, a collet with a tool is attached to the concave portion of the front mass 2b of the bolted Langevin type ultrasonic transducer having the configuration shown in FIG. 4, and the vibration displacement amount of the tip of the tool is also changed to the vertical direction. An experiment was conducted in which measurement was performed in both lateral directions. In this experiment, as a model of a drill assumed as a tool, a rod body having a length of 40 mm and a diameter of 3 mm and a circular cross section was selected, and this rod body was protruded to the lower end of the collet and mounted with a length of 14.8 mm. The measurement was performed using a sonic machining tool model.

In the above-mentioned measurement experiment of the vibration displacement amount of the tool tip, it was obtained by the impedance analyzer about the ultrasonic machining tool model configured by mounting the collet and the tool on the bolted Langevin type ultrasonic transducer of the configuration shown in FIG. Based on the admittance curve, the resonance frequency on the high frequency side was set to 30.20 KHz and the resonance frequency on the low frequency side was set to 21.09 KHz, and voltages having respective frequencies were applied to the bolted Langevin type ultrasonic transducer.
As a result of this measurement experiment, the vertical vibration displacement amount of the tip of the tool mounted on the ultrasonic vibrator vibrated by applying the voltage of the resonance frequency on the high frequency side was 8.33 μmp-p, It was found that the vibration displacement amount was 0.787 μmp-p and the electric power required for the vibration was 1.17 W. On the other hand, the vertical vibration displacement amount of the tip of the tool mounted on the ultrasonic vibrator vibrated by applying the voltage of the resonance frequency on the low frequency side is 7.70 μmp-p, and the horizontal vibration displacement amount is Was found to be 0.248 μmp-p, and the power required for the vibration was found to be 0.31 W

  Therefore, from the results of the above measurement experiment, the same vertical vibration displacement amount was obtained for ultrasonic vibrations at any resonance frequency, but for the horizontal vibration displacement amount, the resonance frequency on the low frequency side It was found that the vibration due to the application of the voltage is about 1/3 (0.248 / 0.787) as compared with the vibration due to the application of the voltage of the resonance frequency on the high frequency side (longitudinal primary vibration). In addition, the amount of power consumption is about ¼ (0.31 /1.17), it was confirmed that the amount of electric power used for exciting ultrasonic vibrations was significantly reduced.

  From the experimental results described above, a vibration excitation method for an ultrasonic transducer by applying a voltage having a resonance frequency corresponding to an admittance peak appearing on a lower frequency side than the resonance frequency for exciting longitudinal primary vibration of the ultrasonic transducer. It has been found that by utilizing the above, not only the electric power required for the vibration excitation but also the lateral vibration (rolling) excited accompanying the longitudinal vibration is significantly reduced.

  Next, the inventor of the present invention has the following characteristics of the vibration of the ultrasonic vibrator generated by applying a voltage of a resonance frequency corresponding to an admittance peak appearing on a lower frequency side than the resonance frequency for exciting the longitudinal primary vibration of the ultrasonic vibrator. In order to clarify the above, using the commercially available finite element analysis software ANSYS (sold by: Ansys Japan Co., Ltd.), the Langevin type ultrasonic transducer of FIG. The ultrasonic vibration excited when constrained under the constraint condition of the ultrasonic transducer for which the admittance curve was obtained was analyzed.

  As a result of the analysis of ultrasonic vibrations by the finite element method described above, ultrasonic waves generated by applying a voltage of a resonance frequency corresponding to the admittance peak appearing on the lower frequency side than the resonance frequency that excites the longitudinal primary vibration of the ultrasonic vibrator. As is clear from the ANSYS analysis image of FIG. 7, the vibration of the vibrator is a reciprocating motion in which the entire ultrasonic vibrator vibrates in the same vertical direction (long-axis direction of the ultrasonic vibrator). It has been found that the vibration is ultrasonic vibration (in the present specification, this vibration is referred to as pseudo-longitudinal zero-order vibration) in which there is no portion serving as a vibration node inside the vibrator. According to the image of FIG. 7, in this pseudo-vertical zero-order vibration, a node of vibration appears at a portion where the annular support frame contacts the base, and the annular support frame itself also has the same ultrasonic vibration. It was also found to carry out ultrasonic vibration of the phase. That is, the ultrasonic vibration of the pseudo vertical zero-order vibration is a reciprocating motion in which the entire ultrasonic vibrator vibrates in the same vertical direction, and has one portion that serves as a node of vibration inside the ultrasonic vibrator. This is a vibration that is clearly different from the longitudinal primary vibration, which is a mode that shows vibrations that are opposite to each other in the longitudinal direction with the part serving as the node as a boundary, and therefore the loss of applied electric energy is small and inevitable. It is presumed that this may result in the advantage of less lateral vibration.

  On the other hand, the vibration generated by the voltage of the resonance frequency that excites the longitudinal primary vibration of the ultrasonic vibrator is, as is clear from the ANSYS analysis image of FIG. This is a mode in which there is one and vibrations are generated in opposite directions in the vertical direction with the node portion as a boundary.

  The present invention has been completed based on the above-mentioned novel findings by the present inventor regarding excitation of ultrasonic vibrations in a Langevin type ultrasonic vibrator.

  Therefore, according to the present invention, there is provided a Langevin type ultrasonic transducer including a metal block, a metal block provided with a supporting frame body annularly protruding on a side surface, and a polarization-processed piezoelectric element fixed between these metal blocks. The Langevin type ultrasonic transducer was prepared and connected to the base via the supporting frame to support the ultrasonic transducer in a restrained state, and then, the piezoelectric element of the ultrasonic transducer was perpendicular to the plane of the piezoelectric element. To the Langevin type ultrasonic transducer by applying a voltage having a frequency capable of exciting ultrasonic vibration consisting of reciprocating vibration having no vibration node inside the ultrasonic transducer in a direction. A Langevin type ultrasonic wave which excites ultrasonic vibration (quasi-longitudinal zero-order vibration) consisting of reciprocating vibration having no vibration node inside the ultrasonic vibrator in a direction perpendicular to the plane of the piezoelectric element. The novel vibration excitation method of Doko is provided.

  Further, according to the present invention, in the vibration exciting method for an ultrasonic vibrator described above, the frequency capable of exciting the pseudo longitudinal zero-order vibration is lower than the resonance frequency exciting the vibration in the longitudinal primary vibration mode of the vibrator. A vibrational excitation method is also provided, which is a frequency falling within the frequency range.

  Further, according to the present invention, in the vibration exciting method for the ultrasonic vibrator, a vibration is provided at a portion where the annular support frame is in contact with the base, and the ultrasonic vibration vibrates in the same phase as the ultrasonic vibration. An excitation method is also provided.

  Furthermore, according to the present invention, a Langevin type ultrasonic transducer including a metal block, a metal block provided with a supporting frame body protruding in an annular shape on a side surface, and a polarized piezoelectric element fixed between these metal blocks. An ultrasonic processing device is prepared in which a tool is connected to one end of this Langevin type ultrasonic transducer and is connected to a base through the support frame to be supported in a restrained state. A voltage having a frequency capable of exciting a reciprocating motion having no vibration node inside the ultrasonic transducer in a direction perpendicular to the plane of the piezoelectric element is applied to the piezoelectric element of the ultrasonic transducer. The ultrasonic vibration is transmitted to the tool by exciting ultrasonic vibration consisting of reciprocating vibration having no vibration node inside the ultrasonic vibrator in a direction perpendicular to the plane of the piezoelectric element. That Ultrasonic machining method according to symptoms is provided.

  Furthermore, according to the present invention, there is provided an ultrasonic machining method according to the ultrasonic machining method, wherein the tool is a tool that rotates around a central axis of the Langevin type ultrasonic transducer.

  Still further, according to the present invention, there is provided an ultrasonic machining method in which the tool is a tool that reciprocates in a direction along the central axis of the Langevin type ultrasonic transducer.

  Furthermore, according to the present invention, a Langevin type ultrasonic transducer including a metal block, a metal block provided with a supporting frame body protruding in an annular shape on a side surface, and a polarized piezoelectric element fixed between these metal blocks. An ultrasonic transmission device was prepared in which the Langevin type ultrasonic transducer was connected to the base through the support frame while the ultrasonic transmission tool was connected to one end of the ultrasonic transducer, and was supported in a restrained state. , A voltage having a frequency capable of exciting the piezoelectric element of the Langevin type ultrasonic transducer in a reciprocating motion having no vibration node inside the ultrasonic transducer in a direction perpendicular to the plane of the piezoelectric element To excite ultrasonic vibration (pseudo longitudinal zero-order vibration) consisting of reciprocating vibration having no vibration node inside the ultrasonic vibrator in a direction perpendicular to the plane of the piezoelectric element, Ultrasonic transmission Ultrasonic transmission method characterized by transmitting the ultrasonic vibration is provided.

  The vibration excitation method for an ultrasonic vibrator of the present invention realizes excitation of longitudinal zero-order vibration, which is a new mode of ultrasonic vibration of the ultrasonic vibrator. Then, in the ultrasonic machining method using the vibration exciting method of the ultrasonic vibrator of the present invention, it is possible to save power in ultrasonic machining using the ultrasonic vibrator and also to improve the processing accuracy. Further, in the ultrasonic wave transmitting method using the vibration exciting method of the ultrasonic vibrator of the present invention, it is possible to reduce the power consumption of ultrasonic wave transmission, and further, the ultrasonic vibration of the pseudo longitudinal zero-order vibration generated from the ultrasonic vibrator. Exhibits high directivity, which enables efficient transmission of ultrasonic vibrations.

It is a figure which shows the structure of a typical bolted Langevin type ultrasonic transducer. It is a figure which shows the example of a structure of the ultrasonic processing apparatus which utilizes a bolting Langevin type ultrasonic transducer. It is a figure which shows the example of the support fixation (restriction) structure of the ultrasonic transducer which can be utilized for the vibration excitation method of the ultrasonic transducer of this invention. It is a figure which shows the example of a structure of the ultrasonic transducer which can be utilized for the vibration excitation method of the ultrasonic transducer of this invention. . It is a figure which shows the admittance curve showing the frequency characteristic in the unrestrained state of the ultrasonic transducer | vibrator shown in FIG. FIG. 5 is a diagram showing an admittance curve showing frequency characteristics of the ultrasonic transducer of FIG. 4 constrained by the support structure shown in FIG. 3. It is a figure which shows the vibration mode (quasi-longitudinal zero-order vibration) generated by the vibration excitation method of the ultrasonic transducer | vibrator according to this invention based on the evaluation result by a finite element method. It is a figure which shows the vibration mode which generate | occur | produces by the longitudinal primary vibration of an ultrasonic transducer based on the evaluation result by the finite element method. FIG. 6A is a diagram showing a vibration mode of a longitudinal primary vibration of the ultrasonic transducer and FIG. 7B is an enlarged diagram showing the behavior of the piezoelectric element portion. It is a figure which shows typically the vibration mode of the pseudo longitudinal 0th-order vibration utilized by the vibration excitation method of the ultrasonic vibrator of this invention. It is a figure which shows the other example of the shape and size of an ultrasonic vibrator utilized for the vibration excitation method of the ultrasonic vibrator of this invention, and a support fixing structure. FIG. 12 is a diagram showing an ultrasonic vibration (pseudo longitudinal zero-order vibration) generated by excitation in the support fixing structure of the ultrasonic vibrator shown in FIG. 11 as an image by the finite element method. The figure which shows another example of the support fixing structure of the ultrasonic vibrator utilized for the vibration excitation method of the ultrasonic vibrator of this invention, and the ultrasonic vibrator in this support fixing structure is a pseudo according to this invention. It is a figure (B) which shows the vibration mode of ultrasonic processing which uses it combining the vertical zero-order vibration and the vertical primary vibration utilized by the prior art. It is a figure which shows the structural example of the punching device which uses a drill as a tool which is one aspect | mode of the ultrasonic processing apparatus used for implementation of the ultrasonic processing method of this invention. It is a figure which shows the structural example of the polishing device which uses a polishing tool as a tool which is one aspect | mode of the ultrasonic processing apparatus used for implementation of the ultrasonic processing method of this invention. It is a figure which shows the structural example of the grinding device which uses a cutter (cutting tool) as a tool which is one aspect | mode of the ultrasonic processing apparatus used for implementation of the ultrasonic processing method of this invention. It is a figure showing the example of composition of the washing machine provided with the ultrasonic transducer which is one mode of the ultrasonic transmission device used for implementation of the ultrasonic transmission method of the present invention. It is a figure which shows the structural example of the ultrasonic sonar which is one aspect | mode of the ultrasonic transmission apparatus used for implementation of the ultrasonic transmission method of this invention.

  The resonance frequency used in the novel vibration excitation method of the ultrasonic oscillator of the present invention (to the admittance peak appearing on the lower frequency side than the admittance peak corresponding to the resonance frequency for exciting the vibration of the longitudinal primary vibration mode of the ultrasonic oscillator The presence of a corresponding resonant frequency: herein referred to as the resonant frequency that excites the pseudo-longitudinal zero-order vibration) has, to the knowledge of the inventor, never been recognized by a person skilled in the art. Further, as far as the present inventor knows, the vibration excitation method of the ultrasonic vibrator utilizing the pseudo vertical zeroth order vibration has never been carried out so far.

  In order to carry out the vibration excitation method of the ultrasonic vibrator using the resonance frequency for exciting the pseudo longitudinal zero-order vibration according to the present invention, first, firmly mount the ultrasonic vibrator on a support (base) assumed outside. It is necessary to manufacture an ultrasonic transducer provided with an annular support frame having a structure as shown in FIG. 4 that can be supported and fixed (restrained). Then, the ultrasonic transducer thus manufactured is supported and fixed (restricted) by the housing at the peripheral portion of the annular support frame by the method shown in FIG. In addition, in FIG. 3, the annular support frame body 6 is formed on the front mass 2b, but the annular support frame body may be formed on the rear mass. Further, it is desirable that the annular support frame is formed integrally with the front mass or the rear mass. However, the independently formed annular or disc-shaped support frame is mounted and fixed to the front mass or the rear mass, or It can also be mounted and fixed between the rear and the rear mass.

  Next, the vibration characteristics of the ultrasonic transducer supported and fixed using the annular support frame as described above are measured by an impedance analyzer to obtain an admittance curve as shown in FIG. If two peaks (admittance peaks) as shown in FIG. 6 appear on the admittance curve, the frequency of the peak appearing on the high frequency side is usually the resonance frequency of the longitudinal primary vibration excitation, and the frequency of the peak appearing on the low frequency side is pseudo. It can be determined that this is the resonance frequency that can be used to excite the vertical zero-order vibration. If necessary, obtain the admittance curve by using an impedance analyzer with the ultrasonic transducer in an unrestrained state, and excite the frequency corresponding to the admittance peak appearing in the admittance curve (excitation of longitudinal primary vibration). It is also possible to confirm that the resonance frequency on the high frequency side corresponds to the resonance frequency of the longitudinal primary vibration excitation based on the comparison between the resonance frequency) and the frequency of the admittance peak on the high frequency side.

  Depending on the shape of the ultrasonic oscillator, the admittance peak of the longitudinal primary vibration may not appear in the admittance curve. In that case, according to the method using a known calculation formula, the resonance frequency for exciting the longitudinal primary vibration is estimated, and the frequency of the admittance peak appearing in the region on the lower wavelength side than the resonance frequency is the frequency of the pseudo longitudinal zero-order vibration. It is also possible to excite the target pseudo longitudinal zero-order vibration by applying a voltage having the frequency of this pseudo longitudinal zero-order vibration.

  On the other hand, even when three or more admittance peaks appear in the admittance curve, the resonance frequency that excites the longitudinal primary vibration is estimated by the above method, and the frequency of the admittance peak that appears in the region on the lower wavelength side than the resonance frequency is estimated. It is also possible to excite the target pseudo-longitudinal zero-order vibration by applying a voltage having the frequency of the pseudo-longitudinal zero-order vibration as a frequency of the pseudo-longitudinal zero-order vibration.

  A tool is attached to the above ultrasonic vibrator to form a vibration tool for ultrasonic machining, and a voltage having a resonance frequency for quasi-vertical zero-order vibration excitation determined by the above method is applied to the vibration tool for ultrasonic machining. By doing so, the pseudo longitudinal zero-order vibration can be excited in the tool. However, the resonance frequency for the pseudo longitudinal zero-order vibration excitation determined by the above method is the resonance frequency confirmed by the measurement in the state where the tool and the tool mounting tool such as the collet are not mounted, so the pseudo longitudinal There may be some deviation from the optimum resonance frequency that can excite the zero-order vibration. Further, even a slight deviation of the constraint condition (supporting and fixing condition) of the vibration tool for ultrasonic machining may cause the deviation of the optimum resonance frequency. Therefore, in determining the resonance frequency for exciting the pseudo longitudinal zero-order vibration of the ultrasonic vibrator with the tool attached and constrained to the base, it is possible to determine the optimum resonance frequency while checking the ultrasonic vibration to be excited. It is desirable to use an ultrasonic oscillator circuit capable of tracking the resonance frequency.

  Even if an ultrasonic transducer having a structure as shown in FIG. 4 is manufactured, and an admittance curve is obtained using an impedance analyzer in a state where the ultrasonic transducer is constrained by the supporting and fixing structure as shown in FIG. When a plurality of (usually two) admittance peaks as shown in FIG. 6 do not appear, the constraint condition of the ultrasonic transducer is adjusted so that the admittance having two peaks as shown in FIG. Sometimes a curve can be obtained. However, if the admittance curve having two peaks as shown in FIG. 6 cannot be obtained even by adjusting the constraint conditions of the ultrasonic transducer, setting the shape of the ultrasonic transducer, Since it is considered that the supporting and fixing structure of the ultrasonic transducer is not suitable for exciting the intended pseudo longitudinal zero-order vibration, the constraint conditions of the ultrasonic transducer of FIG. 3 and the ultrasonic transducer of FIG. It is necessary to redesign the ultrasonic transducer and re-examine the supporting and fixing structure with reference to the shape and size of the above. It should be noted that the constraint conditions of the ultrasonic transducer of FIG. 3 and the shape and size of the ultrasonic transducer of FIG. 4 are merely representative of the modes for carrying out the method of the present invention. It is not a condition that limits the embodiment of the method of exciting the pseudo longitudinal zero-order vibration of the vibrator.

  As described above, the present inventor has found that the ultrasonic vibration generated by the vibration excitation method for an ultrasonic vibrator of the present invention is “a vibration node is formed inside the vibrator in a direction perpendicular to the plane of the piezoelectric element. It is said that the ultrasonic vibration is composed of reciprocating vibration that does not have. Next, the data on which this conclusion is based will be explained again.

  As described above, the existence of the admittance peak appearing on the low frequency side of the admittance curve in FIG. 6 is not known to the inventor of the present invention. Therefore, the inventor could not initially determine what the frequency corresponding to the frequency position at which the admittance peak on the low frequency side appears means. However, as is clear from the experimental facts described so far, the frequency corresponding to the frequency position where the admittance peak on the low frequency side appears is also the resonance frequency of the ultrasonic transducer, and the voltage of the resonance frequency is applied. It was confirmed that the longitudinal ultrasonic vibration excited by the ultrasonic transducer in the restrained state was generated with less power consumption, and the horizontal vibration was less.

  Therefore, in order to analyze the vibration mode of the ultrasonic vibration confirmed this time, the present inventor uses the commercially available calculation software ANSYS based on the finite element method and uses the ultrasonic wave used in the experiment. We analyzed the vibration mode of the ultrasonic vibration generated in the ultrasonic transducer under the conditions of the shape, size and material of the transducer and the fixed condition (constraint condition) of the ultrasonic transducer. The analysis results of the vibration mode are shown in FIGS. 7 and 8.

  As described above, FIG. 7 is an image showing a vibration mode that appears when a voltage having a resonance frequency on the low frequency side is applied to the ultrasonic transducer under the constraint condition according to the present invention. The vibration that appears in the ultrasonic transducer is the vibration in which the entire ultrasonic transducer moves in one direction, and the node of the vibration does not exist inside the ultrasonic transducer, and the vibration of the annular support frame of the ultrasonic transducer is not present. It can be seen that it exists at the outer end (corresponding to the connection to the base). Next, FIG. 8 is an image showing a vibration mode that appears when a voltage having a resonance frequency on the high frequency side is applied to the ultrasonic transducer under the constraint condition, and from this image, the ultrasonic transducer appears. It can be seen that the vibration is a stretching vibration that has a node inside the ultrasonic vibrator and vibrates up and down with the node as a boundary.

  FIG. 9 is a diagram schematically illustrating the vibration mode represented by the image shown in FIG. 7. That is, in the ultrasonic vibration of the vibration mode according to the present invention, the ultrasonic vibrator as a whole repeats the reciprocating vibration vibrating in one direction. The annular support frame that supports and fixes the ultrasonic transducer to the base has a node at the connection part with the base (corresponding to the peripheral edge of the annular support frame) and corresponds to the connection part of the ultrasonic transducer. The inner peripheral portion of the annular support frame also exhibits a reciprocating vibration in synchronization with the ultrasonic transducer. This vibration mode corresponds to the pseudo vertical zero-order vertical vibration mode described in this specification.

  FIG. 10A is a diagram schematically illustrating the vibration mode represented by the image shown in FIG. That is, in the ultrasonic vibration of FIG. 8, the ultrasonic vibrator has a node at a substantially central portion where the piezoelectric element exists (a position where the piezoelectric element exists) and repeats a vibration that vertically expands and contracts (longitudinal primary vibration). .. Since the longitudinal primary vibration is such a stretching vibration, when exciting the longitudinal vibration of the surface (lower side surface) on one side where the tool is mounted, the lower vibration realized by the pseudo longitudinal zero-order longitudinal vibration mode shown in FIG. It is estimated that relatively large electric power is required to obtain a vibration amount (displacement amount) equivalent to the longitudinal vibration of the side surface.

  FIG. 10B is a diagram schematically showing an enlarged view of the vibration of the ultrasonic transducer shown in FIG. 10A, showing the deformation of the piezoelectric element 3 caused by the application of electric energy. It is a figure which shows a condition (estimated condition) typically. That is, the piezoelectric element 3 repeats expansion and contraction due to fluctuations in the applied electric energy, but at the time of expansion, as shown in the figure, the central portion expands against the pressure applied to the piezoelectric element. It is thought that it transforms so that it appears. Therefore, if the deformation of this piezoelectric element does not occur in a completely symmetrical shape at its center, the upper and lower end faces of the ultrasonic transducer will not be completely parallel to the center plane of the stretching vibration, and therefore It is presumed that lateral vibration is likely to occur on the upper and lower end surfaces of the sound wave vibrator.

  FIG. 11 is a diagram showing another example of the shape and size (unit: mm) of the ultrasonic oscillator and the supporting and fixing structure that can be used in the vibration excitation method for the ultrasonic oscillator of the present invention, and FIG. FIG. 12 is a diagram showing ultrasonic vibrations (pseudo-longitudinal zero-order vibrations) generated by excitation in the support fixing structure of the ultrasonic vibrator shown in FIG. 11 as an image obtained by the finite element method. Similar to the image shown in FIG. 7, the vibration that appears in the ultrasonic transducer is reciprocating vibration in which the entire ultrasonic transducer moves in one direction, and the node of the vibration must not exist inside the ultrasonic transducer. Instead, it exists at the outer end (corresponding to the connection to the base) of the annular support frame of the ultrasonic transducer.

  The pseudo longitudinal zero-order vibration excited by the ultrasonic transducer according to the present invention can be used in combination with the conventional longitudinal first vibration. The mode of use will be described with reference to FIGS. 13 (A) and 13 (B).

  FIGS. 13A and 13B are views showing another example of the supporting and fixing structure of the ultrasonic vibrator used in the vibration exciting method of the ultrasonic vibrator of the present invention, and this supporting and fixing structure, respectively. It is a figure which shows the vibration mode of ultrasonic machining which uses an ultrasonic vibrator combining the pseudo longitudinal zero-order vibration according to this invention, and the longitudinal primary vibration utilized by the prior art. For example, when the ultrasonic vibrator of FIG. 13A is used for a cutting process in which a cutting blade (cutter) is attached to the end portion of the right front mass of the ultrasonic vibrator, the work efficiency of the cutting operation with the cutting blade is improved and cutting is performed. In order to prevent the local fatigue of the blade, an embodiment is conceivable in which the ultrasonic vibrator alternately generates the vibration in the pseudo longitudinal zero-order vibration mode and the vibration in the longitudinal first-order vibration mode shown in FIG.

  FIG. 14: is a figure which shows the structural example of the drilling device which uses a drill as a tool (tool which rotates around the central axis of an ultrasonic transducer) which is one mode of utilization of the ultrasonic processing method of this invention (ultrasonic wave. The illustration of the oscillator circuit is omitted). FIG. 14 shows a device using a Langevin type ultrasonic vibrator capable of giving ultrasonic vibration of pseudo longitudinal zero-order vibration of the present invention as an ultrasonic vibrator of an ultrasonic machining device using a drill as a tool.

  The ultrasonic processing apparatus shown in FIG. 14 includes a motor 21, a motor shaft 22, a motor base 23, a coupling (coupling) 24, a rotary shaft 25, a rotary transformer fixing portion 26a, a rotary transformer rotating portion 26b, and a fixed side transformer base 27. A tool is provided for an ultrasonic transducer supporting and rotating device including a sleeve 28, a rotating transformer stand 29, an outer spacer ring 30, a case 31, a housing 32, an outer spacer 33a, an inner spacer 33b, and a bearing 34. The Langevin type ultrasonic transducer is installed. This ultrasonic oscillator supporting and rotating device is a device generally used as an ultrasonic oscillator supporting and rotating device in an ultrasonic processing device.

  A Langevin type ultrasonic transducer having a configuration in which the piezoelectric elements 35a and 35b are sandwiched between the front mass 36 and the rear mass 37 and fixed by tightening bolts 38 at the lower end portion of the ultrasonic transducer supporting and rotating device is a nut 39 ( It is mounted and fixed (restrained) by itself being mounted and fixed to the base. A collet 40 is attached and fixed to the recess of the front mass 36 of the Langevin type ultrasonic transducer by a collet nut 41, and a drill 42 which is a tool is attached and fixed to the collet 40.

  FIG. 15 is a diagram showing an example of the configuration of a polishing apparatus that uses a polishing tool as a tool (a tool that rotates around the central axis of an ultrasonic transducer), which is one mode of use of the ultrasonic processing method of the present invention. The illustration of the sound wave oscillation circuit is omitted). The ultrasonic oscillator supporting and rotating device of the polishing apparatus of FIG. 15 has the same configuration as the ultrasonic oscillator supporting and rotating device of the ultrasonic processing device shown in FIG. The polishing apparatus of FIG. 15 also has a structure in which the piezoelectric elements 35a and 35b are sandwiched between the front mass 36 and the rear mass 37 at the lower end of the ultrasonic vibrator supporting and rotating device and fixed by tightening with the bolt 38. The Langevin type ultrasonic transducer is attached (fixed) by a nut 39. A ring-shaped grindstone 43, which is a tool, is attached and fixed to the lower end portion of the front mass 36 of the Langevin type ultrasonic transducer via a grindstone base (usually made of aluminum alloy) 44.

  FIG. 16: is a figure which shows the structural example of the grinding device which uses a cutter as a tool (tool which reciprocates in the axial direction of an ultrasonic transducer) which is one mode of utilization of the ultrasonic processing method of this invention. In this grinding device, one or both of the grinding device and the material to be machined (workpiece) move horizontally so as to change the relative positional relationship, and the cutter 52 mounted on the ultrasonic vibrator vibrates vertically ( The ultrasonic transducer support structure does not rotate due to the reciprocating motion. Therefore, in the grinding device of FIG. 16, the piezoelectric elements 35a and 35b are sandwiched between the front mass 36 and the rear mass 37 having the annular support frame 36a on the inner lower side of the cylindrical housing 51, and the bolts 38 are tightened. The Langevin type ultrasonic transducer having a fixed structure is mounted and fixed (restricted) by a nut 39 (which is itself mounted and fixed to the base). Then, a collet 40 is attached and fixed to the concave portion of the front mass 36 of the Langevin type ultrasonic transducer by a collet nut 41, and a cutter 52 which is a tool is attached and fixed to the collet 40.

  The electrode plates 53a and 53b formed on the respective surfaces of the piezoelectric elements 35a and 35b are electrically connected to the ultrasonic oscillation circuit 54 and apply electric energy to the ultrasonic oscillator.

  In the grinding apparatus of FIG. 16, the foamed resin 55 is filled as a means for ensuring the fixation of the Langevin type ultrasonic transducer inside the housing 51.

  FIG. 17 is a diagram showing a configuration example of a cleaning device provided with an ultrasonic transducer, which is one mode of an apparatus using the ultrasonic wave transmitting method of the present invention. In the device of FIG. 17, a Langevin type ultrasonic transducer having a configuration in which the piezoelectric elements 35a and 35b are sandwiched between the front mass 36 and the rear mass 37 and the bolt 38 is fixed by tightening the nut formed in the rear mass 37 is a nut 39. Is mounted and fixed (constrained) on the housing 51. A vibration plate 56, which is attached to the bottom of a cleaner (not shown), is attached and fixed to the upper end of the front mass 36 of the Langevin type ultrasonic transducer by bolts 57.

  FIG. 18 is a diagram showing a configuration example of an ultrasonic sonar, which is one mode of an apparatus using the ultrasonic transmission method of the present invention. Also in the ultrasonic sonar of FIG. 18, a Langevin type ultrasonic transducer having a configuration in which the piezoelectric elements 35a and 35b are sandwiched between the front mass 36 and the rear mass 37 and the bolt 38 is fixed by tightening the nut formed in the rear mass 37 The nut 39 is mounted and fixed (constrained) on the housing 51. Then, a transmitter 58 for transmitting ultrasonic waves into the air is attached and fixed to the upper end of the front mass 36 of the Langevin type ultrasonic transducer via a bolt 57.

  The apparatus that can be used to carry out the ultrasonic machining method and the ultrasonic transmission method using the pseudo longitudinal zero-order vibration of the present invention is not limited to the apparatus having the configuration shown in the accompanying drawings. That is, bending processing using ultrasonic waves, deep drawing processing, ironing processing, plastic processing such as drawing processing, grinding processing using ultrasonic waves, free abrasive grain processing using ultrasonic waves, joining processing using ultrasonic waves, Plastic molding using ultrasonic waves, micro processing using ultrasonic waves, dispersing device and atomizing device using ultrasonic waves, ultrasonic motor, ultrasonic cataract surgery device, ultrasonic crushing suction device, ultrasonic calculus crushing device , Ultrasonic dental treatment equipment, ultrasonic continuous casting equipment, ultrasonic erosion testing equipment, polyethylene cross-linking equipment, ultrasonic drying equipment, ultrasonic air sensors, ultrasonic flowmeters, etc. The pseudo-longitudinal zero-order vibration provided by the vibration excitation method of the present invention can be used in various devices using a sound wave oscillator.

1 Bolting Langevin type ultrasonic transducer 2a Metal block (rear mass)
2b Metal block (front mass)
3 Piezoelectric Element 4 Bolt 5a Copper Electrode 5b Copper Electrode 6 Annular Support Frame 7 Nut 10 Ultrasonic Grinding Machine 11 Housing 12 Horn 13 Grinding Tool

Claims (6)

  A Langevin type ultrasonic vibration including a first metal block, a second metal block having a support frame protruding in an annular shape on its side surface, and a polarized piezoelectric element fixed by a bolt between these metal blocks. A child is prepared, the Langevin type ultrasonic transducer is connected to the base through the support frame and supported in a restrained state, and then the piezoelectric element of the Langevin type ultrasonic transducer is operated in the longitudinal primary vibration mode. A step of applying a voltage of a frequency capable of exciting vibration to excite ultrasonic vibration of a longitudinal primary vibration mode, and a resonance capable of exciting vibration of the Langevin type ultrasonic vibrator in a longitudinal primary vibration mode. By applying a voltage having a frequency contained in a frequency range lower than the frequency, a piezoelectric element having a vibration node at a portion in contact with the base of the support frame of the Langevin type ultrasonic transducer is applied. Langevin type vibration excitation method of the ultrasonic transducer, characterized in that a step of exciting the ultrasonic vibrations consisting reciprocal vibration perpendicular to the plane alternately.   A first metal block, a second metal block having a support frame protruding in an annular shape on the side surface and having an opening on the lower side, and a polarized piezoelectric element fixed between these metal blocks with a bolt. A Langevin-type ultrasonic transducer including the above is prepared, the Langevin-type ultrasonic transducer is connected to the base through the support frame to support the tool in a restrained state, and the tool is opened in the opening of the second metal block After applying the voltage to the piezoelectric element of the Langevin-type ultrasonic transducer, which has a frequency capable of exciting the vibration of the longitudinal primary vibration mode, the step of exciting the ultrasonic vibration of the longitudinal primary vibration mode, Then, by applying a voltage having a frequency within a frequency range lower than the resonance frequency capable of exciting the vibration of the first-order longitudinal vibration mode of the Langevin type ultrasonic transducer, A material to be processed is processed by alternately performing a step of exciting ultrasonic vibration consisting of reciprocating vibration perpendicular to the plane of the piezoelectric element having a vibration node at a portion in contact with the base of the support frame of the ultrasonic wave vibrator. A method for ultrasonically processing a material to be processed.   The ultrasonic processing method for a material to be processed according to claim 2, wherein the tool is a tool that rotates about a central axis of the Langevin type ultrasonic transducer.   The ultrasonic processing method for a material to be processed according to claim 3, wherein the tool is a tool selected from the group consisting of an end mill, a drill, a polishing tool, and a grinding tool.   The ultrasonic processing method for a material to be processed according to claim 3, wherein the tool is a tool that reciprocates in a direction along a central axis of the Langevin type ultrasonic transducer.   The ultrasonic processing method for a material to be processed according to claim 5, wherein the tool is a tool selected from the group consisting of a cutting tool, a diaphragm and a welding tool.

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