Elements for ultrasonic motors
|
| · |
High torque without gears at high and low speed |
| · |
Simple structure |
| · |
Large holding torque |
| · |
Can be composed of nonmagnetic materials |
| · |
Excellent response characteristics |
| · |
Lens actuator for automatic focusing camera |
| · |
Turntable for video camera |
| · |
Watch |
|
The operation principle of ultrasonic motor is shown in the figure below.
High-order curling vibration is generated on the surface of the elastic
vibrator (stator) and travelling waves are made by excitation of piezoceramic
vibrator. And the certain pressure causes the slider to propagate on the
stator by the friction between them. Driving force of ultrasonic motor
is obtained by travelling-wave type elastic curling wave. This type of
motor is named as a traveling-wave ultrasonic motor. For generating the
elastic curling wave on the elastic annular plate, adhere the piezoceramic
vibrator beneath the elastic annular plate and exploit the expanding and
contracting move. That is, piezoceramic vibrator beneath the elastic annular
plate is polarized and when AC voltage is applied to the vibrator, sectional
expanding and contracting move occurs and elastic curling waves are generated
on the elastic annular plate.
|
