| 摘要 |
PROBLEM TO BE SOLVED: To obtain substantially maximum drive efficiency, regardless of the drive direction by providing a plurality of displacement elements, and driving the displacement elements in resonance, according to the direction of the drive of a member to be driven. SOLUTION: In a truss-type actuator, a first piezoelectric element 10 and a second piezoelectric element 10' are placed in an intersecting pattern substantially at right angles, and a chip member 20 is bonded to their end on the intersection side. When the piezoelectric elements 10 and 10' are driven by a drive signal having a specified phase difference, the chip member 20 is driven depicting an oval locus. To rotate a rotor 40 clockwise, the rotor is driven by a driven signal with a resonance frequency fa of the first piezoelectric element 10 so that the first piezoelectric element 10 which is displaced, in such a direction as to push the rotor 40 relative to the rotational direction is resonated. To rotate the rotor counterclockwise, the rotor is driven by a drive signal with a resonance frequency fb of the second piezoelectric element 10', so that the second piezoelectric element 10' which is displaced in such a direction as to thrust the rotor 40 relative to the rotational direction is resonated. Thus drive efficiency is kept at substantially the same level and is further substantially maximized in either direction of rotational. |
