| 摘要 |
PURPOSE:To reduce influence of a circumferential elongating and contracting motions to disturb a deflecting vibration to be generated by radial elongating and contracting motions by reducing a circumferential width of a vibrating element. CONSTITUTION:A piezoelectric vibrator 3 provided with an electrode pattern 12 is formed at a stator 1. The vibrator 3 is polarized in the same direction. A vibrating element is formed of a shaded electrode pattern 12. When high frequency voltages phase shifted by 180 deg. are respectively applied to vibrating elements A and -A, regions are alternately elongated and contracted, and a deflecting vibration occurs at the stator 1. In this case, a node is formed at a fine line 13, and a standing wave of triple wavelengths is excited. The vibrating element of an ultrasonic motor is circumferentially divided at 60 deg. or below. Thus, one wavelength becomes 1/2 or below for 120 deg.. The motor is not limited to the triple wavelengths. For example, in the case of double wavelengths, the circumferential angle of the element may be set to 1/4 or 180 deg. of one wavelength, i.e., 90 deg. or below. |
