Laser beam welding apparatus using an ultrasonic motor.

摘要

Herein disclosed is a small-sized ultrasonic motor which can produce a high torque and a stable turning force. The ultrasonic motor comprises: a cylindrical casing; a hollow output shaft extending coaxially through the cylindrical casing and supported rotatably by the same; a ring-like stator fixedly mounted on the inner surface of the cylindrical casing and having piezoelectric elements fixed on the back surface of the same; a ring-like rotor mounted on the hollow output shaft and facing the front surface of the stator; and bias means for pushing the rotor toward the stator. Also disclosed is a laser beam welding apparatus for welding the inner circumferential surface of a tube by using the ultrasonic motor.