| 摘要 |
PURPOSE:To improve efficiency, and to enhance practicability by utilizing longitudinal resonance and torsional resonance, resonance frequency of which is determined by not only a stator body but also the whole motor including a sub-stator. CONSTITUTION:A torsional-vibration piezoelectric ceramic element 3 and a piezoelectric ceramic element 2 for exciting longitudinal vibrations are held by two columnar metallic blocks 3, 4, and clamped by a bolt 5, thus constituting a stator main section. A sub-stator 6 is installed to the lower sections of the metallic blocks 3, 4 through a sliding material 13 such as a bearing in order to bring longitudinal and torsional resonance frequency close. A rotor 8 is pressure-welded to the end face of said stator by using a bearing 9, a nut 10, a pedestal 11 and a coil spring 12 through an abrasion-resistant material 7, thus constructing an ultrasonic motor. Accordingly, AC voltage is applied independently to both ceramic elements 1, 2, the frequency of the ceramic elements 1, 2 is used as resonance frequency, and the phase difference of 90 deg. is given, thus rotating the rotor 8 with high efficiency. |
