Piezoelectric actuator

A piezoelectric actuator for moving an object member by utilizing a dimensional change of a piezoelectric element, comprising an envelope between the piezoelectric element and the object member, said envelope being a cylinder having an open end and a closed end, said cylinder comprising a bellows in a side wall of the cylinder, said open end having a flange extending radially outward from said side wall, said flange being concentrically wave shaped and having an outer fringe, said outer fringe contacting the piezoelectric element directly or via an insulator, such that said envelope hermetically contains a fluid, wherein said closed end is used to move said object member responsive to a dimensional increase or decrease in said piezoelectric element.

A piezoelectric actuator for moving an object member by utilizing a dimensional change of a piezoelectric element, comprising a pressure chamber between the piezoelectric element and the object member, said pressure chamber being cylindrical and bounded by a steel diaphragm member for one end adjacent said piezoelectric element, a rigid ring for a sidewall and a cap member including a plunger barrel for the other end, said steel diaphragm member further comprising a thick circular plate filled into a central recess of an insulator attached to an end of said piezoelectric element and a circular steel diaphragm plate extending radially outward from a peripheral side of said thick circular plate so as to contact said rigid ring, said cap member having a hole, said object member being slidably disposed in said hole, said pressure chamber hermetically containing a fluid, wherein said object member moves within said hole responsive to a dimensional increase or decrease in the piezoelectric element.