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EP0511762A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Piezoelectric sensor

Assignee: Niterra Co Ltd
•
Filing: 1992-04-16
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Granted: —
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Expires: 2012-04-16
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Abstract

Abstract An improved piezoelectric sensor for detecting pressure, vibration, acceleration or the like physical quantity is disclosed. The pressure sensor to be attached to a cylinder block of an internal combustion engine includes a main body (1) adapted to be attached to the cylinder and defining an axially extending hole (4) therewithin, a diaphragm (11) attached to one end of the main body for closing the hole (4); and a piezoelectric element (7) disposed within the hole so that the pressure within the cylinder is transmitted to the piezoelectric element (7) through the diaphragm (11). The piezoelectric element (7) is a circular or polygonal disc with a thickness of 0.3-1.5 mm and is formed of a single crystal piezoelectric ceramic having a Curie temperature of more then 500 °C, such as LiNbO₃.

Inventors

  • 👤 Hideki Toyoda
  • 👤 Takao Kojima
  • 👤 Tetsuma Shimozato

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-06 09:37
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0041; G01L9/008; G01H; G01H11/00; G01H11/06; G01H11/08; G01L23/00; G01L23/08; G01L23/10; G01P; G01P15/00; G01P15/02; G01P15/08; G01P15/09; G01P15/0907

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 100 words
A piezoelectric sensor for an internal combustion engine having a cylinder, comprising: a main body adapted to be attached to the cylinder and defining an axially extending hole therewithin; a diaphragm attached to one end of said main body for closing said hole; and a piezoelectric element disposed within said hole so that the pressure within said cylinder is transmitted to said piezoelectric element through said diaphragm, said piezoelectric element being a circular or polygonal disc with a thickness of 0.3-1.5 mm and being formed of a single crystal piezoelectric ceramic having a Curie temperature of more then 500 °C.
Claim 2
Dependent Claim 16 words
A piezoelectric sensor as claimed in claim 1, wherein said piezoelectric element is formed of LiNbO₃.
Claim 3
Dependent Claim 37 words
A piezoelectric sensor as claimed in claim 1, wherein said piezoelectric element is polarized such that the direction of the polarization is oriented at an angle of 20° or less with respect to the X-Y plane thereof.
Claim 4
Dependent Claim 90 words
A piezoelectric sensor for detecting a physical quantity of a body, comprising a casing to be mounted on said body, a piezoelectric element in the form of a disc disposed in said casing, and means for transmitting said physical quantity to said piezoelectric element as a mechanical strain so that said piezoelectric element outputs an electrical signal, said piezoelectric element being formed of LiNbO₃ and is polarized such that the direction of the polarization is oriented at an angle of 20° or less with respect to the X-Y plane thereof.

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