In a vibration wave driven motor, an elastic body of an elliptic shape is provided where different degrees of stiffness or rigidity are available with the arcuate portions and the straight portions, and the ratio between the distortion energy and the vibration energy that part in the generation of the...http://www.google.com.au/patents/US5128580?utm_source=gb-gplus-sharePatent US5128580 - Vibration wave driven motor
