Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JPS5654198 Page 1 Specification of the Invention The ultrasonic vibrator 1, the first resonator having a plurality of resonant projections, and the second resonator having both end faces substantially planar are opposed to each other with the piezoelectric element interposed therebetween. Let these first one. A female screw is provided on one side of the second resonator, and a male screw is provided on the other, and the male screw and the female screw are screwed through the through holes provided in the piezoelectric element. An ultrasonic wave actuator characterized in that an adhesive is interposed between and fixed to a second resonator and a piezoelectric element. Claims DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ultrasonic transducers used in underwater acoustic transducers and the like. 2 '@@ Conventionally, a vibrator using a piezoelectric element has been used for relatively low frequency as a Langepa buster. Conventionally, this is because the adhesive between the piezoelectric element and the metal resonator had a large loss at high frequencies, and it was possible to use only one piezoelectric element having a shape and a size matching the high frequency. Therefore, conventionally, in the case where only the piezoelectric element is used, the piezoelectric element is made smaller than the wavelength to a size that is considered to make piston movement, and a plurality of such elements are used by being arrayed. 0 FIG. 1 Kn, a conventional vibrator used for relatively high frequency is shown, and electrodes 2.3 are respectively provided on both end faces of a plurality of piezoelectric elements 1 of equal length. The electrode 2 is provided and embedded in a holding member 4 in a predetermined arrangement, leaving the vicinity of one end of the crucible, and the holding member 4 is accommodated in the frame 5. FIG. 2 shows a conventional vibrator having a low Qm, that is, a wide band frequency characteristic. In this case, 04-05-2019 1 a plurality of piezoelectric elements 6.7.8t-0 having different lengths are used, and the holding member 4 is used. The sequence support EndPage: 13G) in the frame 5. However, in such a conventional vibrator, the size of the piezoelectric element 1, 6 ° 67.8 generally has a wavelength because it is necessary to cause the sound emission surface of the piezoelectric element 1.6.7.8 to move in a piston. However, in order to make the directivity characteristic sharper, it is necessary to use a large number of arrays, and the operation of arranging in the holding material 4 is difficult. Further, since the piezoelectric element 1.6.7.8 has many required performance items and is small even if it is expensive 1 ', there is a desire to reduce the number of piezoelectric elements used in terms of cost reduction. An object of the present invention is to provide an ultrasonic transducer capable of simplifying the arrangement operation and reducing the number of expensive piezoelectric elements. The present invention is made by focusing attention on the next point and the like by improving the adhesive and bonding technology, and a first resonator having a plurality of resonant projections forming an acoustic radiation surface on one end face of the piezoelectric element. The second resonator with its both end faces substantially planarized at the other end face is l! r · contact, these first one. One female screw rod is provided on one side of the second resonator, and an external thread is provided on the other, and the external thread and the internal thread are screwed through the through holes provided in the piezoelectric element, and the adhesive It is intended to achieve the purpose by interposing and fixing. Hereinafter, embodiments of the present invention will be described based on the drawings. Here, the same or corresponding components in the respective embodiments use the same reference numerals, and the description of the overlapping components is simplified or omitted. 3 to 6 show a first embodiment of the present invention. In FIG. 3, through holes are formed in the central portion Kr1 of the disk-like piezoelectric element 11, electrodes 13 and 14 are formed on the left and right end faces of the piezoelectric element 11 in FIG. -), (+) Is applied to the electrode 14. The two piezoelectric elements 11 are disposed such that the electrodes 14 of the same polarity face each other with one adhesive 15 as shown in FIG. 4, and one outer end face of the two piezoelectric elements 11 is disposed The first resonator 16 is disposed with the electrode 13 and the adhesive 15 interposed therebetween, and on the other outer end face, the second resonator 17 on the side of the fifth page is made substantially planar on both lake surfaces. It is disposed via the electrode 13 and the adhesive 15. The first of these. The area of the end face of the second resonators 16 and 17 on the side of the piezoelectric element 11 is substantially equal to the area of the end face of the piezoelectric element 11. On the surface of the first resonator 16 on the side not in contact with the piezoelectric element 11, a plurality of resonance projections 18 constituting an acoustic radiation surface are formed at the same height. The height of the resonant projection 18 of the first resonator 16 is such that the total length of the vibrator is half-wave resonant. In this case, the vibration amplitude is small in the vicinity of the piezoelectric element 11. The vibration amplitude is maximized at the tip end face of the resonance projection 18 so that sound waves can be emitted into a medium such as water. 04-05-2019 2 In addition, the thickness of these resonant projections 18 is made sufficiently thin as compared with the wavelength, and the piston movement is performed at the end face 1. An externally threaded portion 19 is integrally formed at the axial center of the first resonator 16 through the through hole 12 of the piezoelectric element 11 and having one end projected on the opposite side. Axial center of the second resonator 17? -It is screwed in the internal thread part 20 formed in l. According to the sixth page, both the piezoelectric element 11 and the surface of the piezoelectric element 11 and the first one. The air gap between the adhesive 15 and the second resonators 16 and 17 is eliminated, and the thickness of the layer of the adhesive 15 is kept as thin as possible to prevent the piezoelectric element 11 and the first . The second resonators 16 and 17 are fixed. Under the present circumstances, since the cross-sectional area of the piezoelectric element 11 is large enough, fastening by external thread part 19 and internal thread application of both valve pendulums 16 and 17 is carried out with a bolt like bolted Langevin vibrator conventionally made. It is not necessary to tighten so as to apply a bias compressive stress, but it is sufficient to fasten the layer of the adhesive 14 as thin as possible and as uniformly as possible as a whole before the adhesive 14 is cured. In such a configuration, when a desired voltage is applied to the electrodes 13 and 14, electricity and vibration are converted by the piezoelectric element 11, and this vibration is converted to the first one. It is transmitted to the second resonator 16 ° 17. At this time, since the second resonator 17a which is the back side diaphragm and the outer end face thereof are planar, the piston movement is not performed, but the radiation end face of the resonator 16 on the acoustic radiation side is a resonant collisional surface. Since the section 18 is made sufficiently narrow as compared with the wave EndPage: 27 page 1 length, a piston movement is performed, and a sound wave is emitted into a medium such as water. According to this embodiment, since the expensive piezoelectric elements 11 are reduced and the acoustic radiation surface is configured using the inexpensive first resonators 16 ', it can be provided at a very low cost as a whole. The respective resonant projections 18 can be sufficiently deflected as compared with the wavelength, so that the vibration of the end face can be effectively piston-operated with the respective resonant projections 18 in the same phase. Furthermore, the first one. Since the second co-1 '' pendulum 16, 17 is joined by the fastening of the external thread 19 and the internal thread 20, the thickness of each layer of adhesive 15 can be made extremely thin and low loss, and 1st. Positioning of the second resonators 16 and 17 is facilitated, which has a great effect on the assembling operation, and is also inexpensive. 7 and 8 show a second embodiment of the present invention, in which the heights of the resonance projections in the first embodiment are made different. That is, in the present embodiment, the male screw portion 19 is opposed to the both end surfaces of the piezoelectric element 110 via the electrodes 13 and 14 and the adhesive 15, and is fastened through the through hole 12 of the piezoelectric element 169 = 1. And the female screw portion 20 attached first. Among the second resonators 16 and 17, a plurality of, e.g., a plum-shaped, five resonance projections disposed integrally with the first resonator 16 are one of the left ends in FIG. The three resonance projections 22 in the central 04-05-2019 3 vertical direction in FIG. 7 are at the middle height, and the one resonance projection 23 at the right end in FIG. 7 is the lowest. There is. These resonant projections 21, 22 and 23 are designed to resonate at a half wavelength at each height, and viewed from the end face of the vibrator, they are arranged as if having a staggered complex resonance, and each of the resonant projections 21 to 21 The vibration amplitude is maximized at its end face, and the sound wave is emitted into the medium. In such a configuration, when a predetermined voltage is applied to the electrode 13.degree. 14 of the piezoelectric element 11, the characteristics shown in FIG. 9 are exhibited. That is, in FIG. 9, when the frequency is taken along the horizontal axis and the sound pressure is taken along the vertical axis, a characteristic P having a peak of sound pressure centered at a relatively low frequency f1 due to the highest resonance projection 21. Is obtained, and a characteristic Q with a peak of sound pressure centered on the intermediate frequency f2 is obtained by the resonance projection 22 at the middle 9 pages 1 height, and is relatively high by the lowest resonance projection n. A characteristic R with a peak of sound pressure centered on the frequency f is obtained, and the frequency f, f2. It can be seen that f, there is a small mountain, and a complex composite characteristic T is obtained, and an extremely broad band (low Qrn) electroacoustic transducer can be realized. According to the present embodiment as described above, the same effect as that of the first embodiment can be obtained, and there is also an effect that a low Qm, a wide band, and a vibrator can be obtained. In addition, it can change suitably according to necessity to the number of resonance protrusions, height, etc. in implementation, and a male screw part and a female screw part are 1st 1. An external thread or an internal thread may be provided in any of the second resonators, as long as they can be screwed to each other. As described above, according to the present invention, it is possible to provide an inexpensive ultrasonic transducer that can reduce the number of expensive piezoelectric elements and can be applied to relatively high frequency regions. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 10 is a cross-sectional view showing another example of a conventional ultrasonic transducer, and FIG. 3 is used in a first embodiment of an ultrasonic transducer according to the present invention. A side view of the piezoelectric element, FIG. 4 is a left side view of the first embodiment of the present invention, FIG. 5 is a half sectional front view of FIG. 4, FIG. 6 is a right side view of FIG. The figure is a left side view of the second embodiment of the present invention, FIG. 8 is a front elevational view of a half section of FIG. 7, and FIG. 9 is a diagram showing sound pressure-frequency characteristics of the second embodiment. 11: Piezoelectric element, 12: through hole, 13, 14: electrode, 15 ′ ′: adhesive, 16: first resonator, 17: second resonator, 18 , 21, 22, 23 · · · Resonant protrusion, 19 · · Male thread, male and female threads. Agent patent attorney Masamoto Akimoto EndPage: 3 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 Figure 2 Figure 9 · 131 EndPage: 4 04-05-2019 4 04-05-2019 5
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