| 摘要 |
PURPOSE: To eliminate the need of making the natural frequency of a stator in the longitudinal direction coincident with that of the stator in the transversal direction in a prescribed vibration mode by establishing an even-multiple relation between the resonance frequency of the stator in the longitudinal direction and that of the stator in the flexural direction. CONSTITUTION: A first oscillation circuit 37 oscillates at 45kHz and a second oscillation circuit 38 oscillates at 90kHz. A third oscillation circuit 36 is set in such a way that, when the output of the first oscillation circuit 37 is sin45t at time (t), the output signal of a third phase shifting circuit 36 can become sin90t by shifting the output of the second oscillation circuit 38 in time. Therefore, a voltage which is the sum of (sin45t+sin90t) is applied across the first- phase input terminal 8C of an ultrasonic motor and the stator of the motor is excited to make 90kHz longitudinal vibration and 45kHz flexural vibration. Therefore, the degree of freedom of a vibration device in design can be increased, because it is not necessary to make the natural frequency of the vibrating elastic body in the extending direction coincident with that of the body in the flexural direction. |
