| 摘要 |
<p>PURPOSE:To prolong the lifetime of a displacement detecting means and facilitate the mounting of a piezoelectric displacement elements into one integrated laminated pizoelectric displacement element by penetrating them with a bolt in the direction of the lamination and attaching a displacement sensor at an axial part of said bolt. CONSTITUTION:A piezoelectric element 1 is an annular one comprising electrodes consisting of a metallic material such as Ag which are formed on both sides of the element 1 and such elements 1 are laminated with an annular voltage applying electrode plate 2 between them. A recess 10 is formed in the longitudinal direction of an axial part of a bolt 9 and a displacement sensor 11, for example, a distortion gauge is bonded to the recess 10 with an adhesive. A lead wire 12 of the displacement sensor 11 is led out to the outside through a groove 13 arranged around an insulator plate 7a. Output signals of the displacement sensor 11 sent through the lead wire 12 are fed back to a drive circuit of a piezoelectric displacing element through a detection circuit and hysteresis of a displaced quantity of the piezoelectric displacing element is removed.</p> |
