Kyocera Corporation

Continental Automotive Gmbh

Siemens Aktiengesellschaft

Harald-Johannes Kastl

Carsten Schuh

Masahiro Inagaki

Bernhard Doellgast

Atsushi Ochi

Takami Sakamoto

A piezoelectric actuator unit which undergoes less change in the amount of displacement and shows high durability in continuous operation under a high voltage and a high pressure over a long period of time is provided. The piezoelectric actuator unit including a multi-layer piezoelectric element having piezoelectric layers and metal layers with the piezoelectric layers and the metal layers being stacked one on another, and a case which houses the multi-layer piezoelectric element, wherein at least one of the plurality of metal layers is stress relieving layer which consists of a plurality of partial metal layers that are scattered throughout the entire region between two piezoelectric layers which adjoin the partial metal layers in the direction of stacking, and voids, and a peel-off section is formed at least in a part of the interface between the stress relieving layer and the piezoelectric layer that adjoins therewith.

Piezoelectric actuator unit having a stress relieving layer and method for manufacturing the same

A multi-layer piezoelectric element includes a stack having metal layers and piezoelectric layers stacked one on another, and a pair of external electrodes formed on the side faces of the stack. At least one of the metal layers is a stress relieving layer having partial metal layers scattered between the two piezoelectric layers and voids. Junction sections are formed between the two piezoelectric layers to join and are disposed on both sides of an imaginary straight line drawn to connect the center of width of one of the external electrodes and the center of width of the other of the external electrodes in a plane including the stress relieving perpendicular to the stacking direction.

Multi-layer piezoelectric element having a plurality of junction sections and injection apparatus employing the same

A multi-layer piezoelectric element having higher durability which experience less decrease in the amount of displacement even when operated continuously over a long period of time under a high pressure and a high voltage is provided. The multi-layer piezoelectric element comprises a plurality of piezoelectric layers and a plurality of internal electrode layers, wherein the piezoelectric layers and the internal electrode layers are stacked alternately one on another, and at least one of the plurality of internal electrode layers contains at least one nitride, titanium nitride or zirconium nitride.

Multi-layer piezoelectric element, injection apparatus using the same and method of multi-layer piezoelectric element

Growing community of inventors

Fichtelberg, Germany

Harald-Johannes Kastl