| 摘要 |
PURPOSE:To prevent lowering of motor efficiency and undesirable fluctuation of operating speed or the like by regulating the phase of the driving voltages of first and second piezoelectric elements, with detection timing of a separation timing means, so that the oscillating speed of an oscillator through the second piezoelectric element is maximized. CONSTITUTION:Differentiators 25, 26 and a clipper 27 are provided with means for detecting the separation timing of a mover and an oscillator based on the fluctuation of the driving voltage for a first piezoelectric element 2. A time constant control circuit 19 regulates the phases of the driving voltages for the first and second piezoelectric elements 2, 3, with thus detected timing, so that the oscillating speed of the oscillator through the second piezoelectric element 3 is maximized. Consequently, the phases of the first and second piezoelectric elements 2, 3 are set so that a maximum output is obtained at all times. |
