| 摘要 |
PROBLEM TO BE SOLVED: To greatly reduce a fluctuation in frictional force caused by an uneven contact, by forming the contact surface of an upper friction member into a projecting shape. SOLUTION: The ultrasonic motor 1 comprises a vibrating body 2 formed out of a piezoelectric element 4, and a rectangular parallelepiped friction member 3 which is fastened to the end surface of the vibrating body 2 and draws an elliptic track according to the vibration of the vibrating body 2, and has a front end surface, that is, a contact surface 3a coming into contact with a body to be driven. The contact surface 3a of the friction member 3 is formed into a curved and projecting shape, and positioned so as to be pressed against the side surface of the body to be driven. When AC voltage is applied to the ultrasonic motor 1, the friction member 3 draws an elliptic track according to the vibration of the vibrating body 2, and moves the body to be driven by friction force developed between the body to be driven and it at that time. The friction member 3 comes into contact with the body to be driven in the center of the contact surface 3a, so that it comes into contact therewith so as to be roughly symmetric with respect to the minor axis of the elliptic track even in case that an uneven contact occurs. It is thus possible to greatly reduce fluctuation in frictional force caused by an uneven contact with the body to be driven. |
