| 摘要 |
PURPOSE:To facilitate varying a displacement arbitrarily with a constant applied voltage and giving the displacement free from hysteresis by a method wherein the number of piezoelectric porcelain layers to which the voltage is applied is arbitrarily determined by switching means. CONSTITUTION:Switches are connected to piezoelectric porcelain layers in such a manner that the number of the piezoelectric porcelain layers to which a voltage is applied is successively doubled in the order of switches when the respective switches are closed. If some of the switches 3 are closed, the voltage is successively applied to the piezoelectric porcelain layers whose number corresponds to the respective switches. As only the piezoelectric porcelain layers to which the voltage is applied create displacements, an arbitrary total displacement corresponding to the number of layers can be obtained by selecting the switches. For instance, if the switch 3a only is closed, one piezoelectric porcelain layer 1 creates the displacement. If the switches 3a and 3b are closed, three piezoelectric porcelain layers created the displacements. If the switches 3b and 3d are closed, ten piezoelectric porcelain layers create the displacement. Thus, by selecting the number of layers to which the voltage is applied, the total displacement can be determined. Although the number of the piezoelectric porcelain layers to be driven is determined by the manual switches in this case, the switches may be semiconductor switches and automatic digital control may be employed by using a numerical controller. |
