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US 6,663,015 B2Granted
Piezoelectric device for injector
AssigneeDenso Corporation
InventorsYutaka Yamada, Masayuki Kobayashi, Naoyuki Kawazoe
Life of this patent
Estimating the term…
Abstract
A piezoelectric device which is applicable, for example, as a drive source for a fuel injector comprises a plurality of piezoelectric layers and a plurality of inner electrode layers stacked alternately with each other. The outer peripheral side surfaces are formed with a pair of outer electrode layers electrically turned on alternately in such a manner that the inner electrode layers located adjacently to each other through the piezoelectric layers have different polarities. Second outer electrode layers configured of a conductive material having a larger breaking elongation than the first outer electrode layers, respectively, are formed on a pair of the first outer electrode layers.
Claims26
A piezoelectric device, built in a fuel injector, for generating the driving force for the injector, comprising;
- a plurality of piezoelectric layers adapted to expand or contract in accordance with the applied voltage and a plurality of inner electrode layers for supplying the applied voltage, said piezoelectric layers and said inner electrode layers being stacked alternately with each other;
- a pair of first outer electrode layers formed on the outer peripheral sides, respectively, of the piezoelectric device for the injector in such a manner that adjacent ones of said outer electrode layers alternately assume electrically positive and negative polarities;
- and
- second outer electrode layers formed on the first outer electrode layers, respectively, and made of a conductive material having a larger breaking elongation than the first outer electrode layers.
1 more element
A piezoelectric device, built in an injector, for generating a drive force for the injector, comprising:
- a plurality of piezoelectric layers adapted to expand or contract in accordance with the applied voltage and a plurality of inner electrode layers for supplying the applied voltage, said piezoelectric layers and said inner electrode layers being stacked alternately with each other;
- a pair of first outer electrode layers formed on the outer peripheral sides, respectively, of the piezoelectric device for the injector in such a manner that adjacent ones of said outer electrode layers alternately assume electrically positive and negative polarities;
- and
- metal members coupled to said first outer electrode layers, respectively, through second outer electrode layers of a conductive material having a larger breaking elongation than said first outer electrode layers.
1 more element
A piezoelectric device, built in an injector, for generating a drive force for the injector, comprising:
- a plurality of piezoelectric layers adapted to expand or contract in accordance with the applied voltage and a plurality of inner electrode layers for supplying the applied voltage, said piezoelectric layers and said inner electrode layers being stacked alternately with each other;
- a pair of first outer electrode layers formed on the outer peripheral sides, respectively, of the piezoelectric device for the injector in such a manner that adjacent ones of said outer electrode layers alternately assume electrically positive and negative polarities;
- and
- metal members coupled to said first outer electrode layers, respectively, through second outer electrode layers of a conductive material having a larger breaking elongation than said first outer electrode layers;
- wherein said metal members are each formed of a metal plate having a corrugated section;
- and
- said metal plates having a corrugated section each have ridge portions protruded outward of the outer peripheral side surface of the piezoelectric device for the injector and valley portions each located between adjacent two of said ridge portions, and in which at least some of said ridge portions and said valley portions are formed diagonally over said piezoelectric layers and said inner electrode layers constituting said piezoelectric device.
4 more elements
A piezoelectric device, built in an injector, for generating a drive force for the injector, comprising:
- a plurality of piezoelectric layers adapted to expand or contract in accordance with the applied voltage and a plurality of inner electrode layers for supplying the applied voltage, said piezoelectric layers and said inner electrode layers being stacked alternately with each other;
- a pair of first outer electrode layers formed on the outer peripheral sides, respectively, of the piezoelectric device for the injector in such a manner that adjacent ones of said outer electrode layers alternately assume electrically positive and negative polarities;
- and
- metal members coupled to said first outer electrode layers, respectively, through second outer electrode layers of a conductive material having a larger breaking elongation than said first outer electrode layers;
- wherein said metal members are each formed of a metal plate having slits or holes;
- and
- said slits are formed diagonally over said piezoelectric layers and said inner electrode layers constituting said piezoelectric device.
4 more elements
A stack type of piezoelectric device built in an injector,
- wherein outer electrodes are arranged on the sides of said piezoelectric device, and external electrodes are arranged on said outer electrodes, respectively, for establishing electric conduction with external parts,
- wherein said external electrodes each include a core member and a metal cover for covering at least a part of said core member, said external electrodes being coupled to at least a part of said outer electrodes, and
- wherein the specific electric resistance of said core member is not less than 5×10−6 (Ω·cm), and the specific electric resistance of the said metal cover is not more than one half of that of said core member.
A stack type of piezoelectric device built in an injector,
- wherein outer electrodes are arranged on the sides of said piezoelectric device, and external electrodes are arranged on said outer electrodes, respectively, for establishing electric conduction with external parts,
- wherein said external electrodes each include a core member and a metal cover for covering at least a part of said core member, said external electrodes being coupled to at least a part of said outer electrodes, and
- wherein the specific electric resistance of said core member is not less than 5×10−6 (Ω·cm), and the specific electric resistance of the said metal cover is not more than one half of that of said core member;
- and
- a substrate material is interposed for improving the closeness between said core member and said metal cover.
2 more elements
A stack type of piezoelectric device built in an injector,
- wherein outer electrodes are arranged on the sides of said piezoelectric device, and external electrodes are arranged on said outer electrodes, respectively, for establishing electric conduction with external parts,
- wherein said external electrodes each include a core member and a metal cover for covering at least a part of said core member, said external electrodes being coupled to at least a part of said outer electrodes, and
- wherein the specific electric resistance of said core member is not less than 5×10−6 (Ω·cm), and the specific electric resistance of the said metal cover is not more than one half of that of said core member;
- and
- said outer electrodes are made of a conductive adhesive containing silver, and at least one of said metal covers is arranged at least on the joint surface between said external electrode and said conductive adhesive.
2 more elements
A stack type of piezoelectric device built in an injector,
- wherein outer electrodes are arranged on the sides of said piezoelectric device, and external electrodes are arranged on said outer electrodes, respectively, for establishing electric conduction with external parts,
- wherein said external electrodes each include a core member and a metal cover for covering at least a part of said core member, said external electrodes being coupled to at least a part of said outer electrodes, and
- wherein the specific electric resistance of said core member is not less than 5×10−6 (Ω·cm), and the specific electric resistance of the said metal cover is not more than one half of that of said core member;
- and
- each of said outer electrodes and the corresponding one of said external electrodes are coupled to each other by a conductive adhesive containing silver, and said metal cover is arranged at least on the joint surface between said external electrode and said conductive adhesive.
2 more elements
Dependencies are inferred from the claim text.