ボルト締め電気ひずみねじり振動子

概要

論文の詳細を見る
Most vibrators used for ultrasonic power applications are longitudinal vibrators. However, progress in ultrasonic power applications demands the development of new types of vibrators. . . torsional vibrators. One example among them is a magnetostrictive torsional vibrator, which has been developed by the present authors. It is in practical use, e. g. , as a surgical operating tool of senile cataract of human eyes etc. But the magnetostrictive torsional vibrator has the following difficulties: (1) The output power of a single vibrator is insufficient in order to be used for ultrasonic machining etc. (2) It is hard, in view of its construction, to drive a plural vibrators in cascade for sufficient power. (3) It is also difficult to attach a vibration monitor to it. (4) A load and the vibrator must be joined together by adhesion, which often comes off from the vibrator, thus lowering the reliability. Under the notion that a bolt-clamped Langevin type electrostrictive torsional vibrator has the possibility of overcoming the difficulties mentioned above, the present authors examined it and found that it has some merits, which a magnetostrictive one does not have, and it is adoptable for ultrasonic power applications. In making up an electrostrictive torsional vibrator for ultrasonic power applications, we adopted bolt-clamped Langevin type'' as shown in Fig. 1-b, using ceramics polarized so as to vibrate in thickness shear mode with Langevin's metal blocks to lower the resonant frequency of the vibrator and to obtain an arbitrary resonant frequency from the same disc. The matal blocks (1), (4) and ceramics (2), in Fig. 1-b, are clamped by bolt (3) and nut (5). In order to polarize the electrostrictive ceramics circumferentially as one body, silver electrodes (hatched portion) are glazed on the ceramics as shown in Fig. 3, and they are polarized eight times one division after another. Polarizing conditions are as follows: (1) In 160℃ silicone oil bath, (2) in an electric field of 13kV/cm between adjacent electrodes, (3) electric field was impressed for 20 minutes per one element. But these conditions are not always best. Nodal plane of the vibrator shown in Fig. 4 is set at C plane. The frequency equations of the vibrator shown in Fig. 4 are expressed as eq. (4) about the division A-B-C, and as eq. (5) about C-D-E-F. In Figs. 5 and 6, there are shown trially made vibrators, the latter has the cascaded structure of A-B-C division of the vibrator shown in Fig. 4. As is seen in the figures, both vibrators have resonant frequencies cloes to the designed one. Torque generated at the small element shown in Fig. 7 is expressed as eq. (9), using Elasto-Piezo-Dielectric Matrix written as eq. (6) or Table 1. Torque generated in the whole cross-section of transducer ceramic is expressed as eq. (10). Putting the integrand of eq. (10) as eq. (11), this is given as Table 2 with the ceramic polarized as Fig. 2. The relation between output torque and the dimensions of the vibrator including material constants is given by this value. The authors show in section 5. 2. 4. that the torque calculated and measured agree well. This electrostrictive torsional vibrator has also some weak points ; (1) It requires polarization as many as eight times to make one thickness-shear mode ceramics. (2) Therefore it is difficult to make small sized vibrators. (3) The whole volume of the electrostrictive ceramics is not used effectively. Selection of the torsional vibrators, magnetostrictive or electrostrictive ones described in this report is not decided easily, but they should be selected according to circumstances.
社団法人日本音響学会の論文
1972-03-10

ボルト締め電気ひずみねじり振動子

スポンサーリンク

概要

著者

関連論文

スポンサーリンク