| 摘要 |
PURPOSE:To obtain an ultrasonic motor which can produce traveling wave on a cylindrical surface by polarizing piezoelectric elements radially in the opposite directions between adjacent elements. CONSTITUTION:A piezoelectric element 1 is polarized radially into phase A and phase B with the minimum unit circumferential length of polarization being set equal to half the wavelength of traveling wave. Adjacent polarization units are polarized in the opposite directions and when a + polarization part is distorted radially outward, a - polarization part is distorted radially inward for same applying voltage. Since phase A and phase B are arranged while being shifted by a quarter wavelength of traveling wave in the circumferential direction, traveling waves are produced on both inner and outer circumferential faces of the piezoelectric element 1 upon application of AC voltages having 90 deg. phase difference for phase A and phase B. According to the constitution, a new type ultrasonic motor producing traveling waves on a cylindrical surface can be realized. |
