Stacked piezoelectric actuator

摘要

Disclosed is a stacked piezoelectric actuator displaceable by bending comprising a plurality of piezoelectric ceramic layers stacked on one surface of a core material, and a plurality of piezoelectric ceramic layers stacked on the other surface thereof, said piezoelectric ceramic layers stacked on both surfaces being successively increased in piezoelectric constant d31 inner layers to outer layers. The piezoelectric coefficient d31 is derived from the following equation (2): <IMAGE> (2) wherein k is the electromechanical coupling coefficient, the length vibration of a rectangular plate is taken as k31, and the unit of the piezoelectric coefficient d31 is C/N (m/V). The piezoelectric coefficient d33 in the longitudinal vibration of a column determined by the following equation (3) is a value for the whole stacked layers, and in the present invention, it is necessary that the piezoelectric coefficient d31 for each of the stacked piezoelectric ceramic layers satisfies the above-mentioned equation. <IMAGE> (3) wherein k is the electromechanical coupling coefficient, and the longitudinal vibration of a column is taken as k33.