US Patent 7355327 Laminated piezoelectric/electrostrictive element

A laminated piezoelectric element is applicable as a driving source of opening and closing mechanism of an injection nozzle in a fuel injecting device. A laminated piezoelectric/electrostrictive element 1 has: a columnar laminate 10 constituted by alternately laminating a plurality of piezoelectric/electrostrictive layers 14 and inner electrode layers 18, 19; and outer electrodes connected to the inner electrode layers 18, 19 every other layer. This laminated piezoelectric/electrostrictive element 1 has stepped portions A formed periodically at every laminating cycle T in a side surface of the columnar laminate 10 of the element, the side surface being parallel to an axial direction (S-direction) of the columnar laminate 10. Due to the constitution mentioned above, the electrode is not easily worn even during an expanding and contracting operation during practical use, and the element can sufficiently circulate and cool a lubricant through the casing even during practical use.