| 摘要 |
PROBLEM TO BE SOLVED: To significantly reduce manufacturing cost by providing independent I/O sections isolated from each other through an insulation groove on one side of a counter electrode and constructing an ultrasonic transformer having respective power I/O sections which utilize coupled and resonating state of radial and axial oscillations. SOLUTION: A common electrode 11 connected with an exciting wire 15 is applied over the entire inner circumferential surface of a tubular piezoelectric ceramic 1 polarized 14 in the radial direction. The electrode on the outer circumferential surface is divided into a 3/4 part and 1/4 part, and an input exciting wire 16 is connected with the 3/4 part 12 while an output wire 17 is connected with the 1/4 part 13. The exciting electrodes 15, 16 are connected with the output part of a power supply 20, including an exciting circuit and an ultrasonic transformer, is excited with a voltage of several volts. When a basic resonance frequency mode along the outer circumference is followed by an oscillation mode of about double the frequency along the length of the tube, the resonance admittance of coupled resonant state is several times as high as that at the basic resonance frequency. Furthermore, coupling coefficient and mechanical quality coefficient are very much increased, and since powerful oscillation energy is stored in the ultrasonic transformer, a high voltage of several hundreds of volts is developed on the output wire 17. |
