| 摘要 |
PURPOSE:To approximately match the resonance frequencies of two standing waves by setting the ratio(R/L) of the length L at the linear part to the average radius R at arched part of a resilient body higher than 1/4. CONSTITUTION:A traveling oscillation wave is formed in an elongated circular resilient body 21, having an arched part 21r of average radius R and a linear part 21l of length L, by means of a piezoelectric element 22. Consequently, the resilient body 21 and members 23-27 pressure jointed thereto are moved relative to a stator 28. At this time, the ratio(R/L) of the length L at the linear part 21l to the average radius R is set higher than 1/4, thus forming the amplitude only on the inner side or the outer side of the linear part 21l of the resilient body 21. By such arrangement, torsional component at the linear part 21l can be suppressed or the direction thereof can be aligned resulting in the improvement of driving characteristics. |
