| 摘要 |
PURPOSE:To achieve a stabilized rotation with high efficiency by configuring vibration characteristics in the circumferential direction and the contacting direction with a driving body, respectively, so that the bending vibration cbaracteristics of a vibration beam has phase lag of about 180 deg. behing the driving freguenoy on the side of a piezoelectric element and has inherent frequency reduced by a factor of an integer. CONSTITUTION:Bending vibration oharacteristics of a vibration beam Z, in the circumferential direction Fr and the contacting direction fs with a driving body 1-b, are configured such that the phase lags about 180 deg. behind the driving frequency fo on the side of a piezoelectric element 1-a and inherent frequencies fr, fs are reduced by a factor of an integer. Upon application of a pulse voltage onto the piezoelectric element 1-a, the driving body 1-b elongates to the right and pushes the vibration beam Z. When the drlving body 1-b inverts motion to the left, it imparts a force onto the vibration beam Z to cause phase lag of 180 deg. thus starting motion in that direction. The driving body 1-b then operates to push the vibration beam Z to the right and siuce the phase is shifted by 180 deg., similarly to the moment when the driving body 1-b detaches from the vibration beam Z, the vibration beam Z performs residual motion to the left. |
