Denso Corporation

Shinya Mitarai

Masayuki Kobayashi

Takashi Yamamoto

Akio Sugiura

Hidekazu Hattori

Atsushi Murai

Kazuhide Sato

Isao Mizuno

A piezoelectric device for an injector, built into an injector and generating driving force of the injector, wherein a relation d(0.1 Ec)/d(1.2 Ec)&gE;0.50 is established between an apparent piezoelectric constant d(1.2 Ec) calculated from static elongation when an electric field of 1.2 Ec is applied to the piezoelectric device in the same direction as a polarizing direction while a preset load of 500 N is applied to the piezoelectric device, and an apparent piezoelectric constant d(0.1 Ec) calculated from static elongation when an electric field of 0.1 Ec is applied to the piezoelectric device in the same direction as the polarizing direction. The piezoelectric device so fabricated has high durability and can be used for a long time. The piezoelectric device is fabricated by alternately laminating a plurality of piezoelectric layers expanding and contracting in proportion to an applied voltage and a plurality of internal electrode layers for supplying the applied voltage, and the sectional shape of the piezoelectric device crossing at right angles the laminating direction is partially or wholly arcuate. The piezoelectric device is accommodated in a cylindrical accommodation space.

Piezoelectric device for injector

A stacked piezoelectric device and a method of fabrication thereof includes a piezoelectric stack having a first side electrode and a second side electrode, piezoelectric layers and internal electrode layers. The piezoelectric layers and internal electrode layers have substantially the same area. The internal electrode layers have ends thereof exposed to one side of the stack. The first side electrode includes first insulative portions formed at the ends of alternate ones of the internal electrode layers and a first conductive portion formed over the first insulative portions. The second side electrode is similarly configured to form insulative portions at the other ends. The first and second insulative portions are formed of an insulative resin, while the first and second conductive portions are formed of a conductive resin. The first and second conductive portions are also formed to directly cover the ends of the internal electrode layers.

Stacked piezoelectric device and method of fabrication thereof

Growing community of inventors

Kuwana, Japan

Shinya Mitarai