| 摘要 |
PURPOSE:To generate a large force in a large displacement by utilizing a laminated electrostrictive plate as an electrostrictive block which forms a piezoelectric element and applying the polarizing direction and reverse polarizing direction of the plate. CONSTITUTION:A piezoelectric element 31 is composed of laminated electrostrictive plates 34, 35 and a central electrode 36. The plates 34, 35 are formed by alternately superposing electrostrictive plates 34a, 34b and 35a, 35b in the polarizing direction as shown by an arrow A so that the polarizing directions of two plates 34b, 35a contacted with the electrode 36 are in the same direction. A voltage higher than the polarization deteriorating voltage is applied in the polarizing direction of the electrostrictive plate through polarity changeover switch 44 from a drive circuit 33, and a voltage lower than the polarization deteriorating voltage is applied in the reverse polarizing direction. Thus, large force can be generated in a large displacement. |
