EP0675355A1
Expired / Lapsed
EP
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Sensor element and particle sensor
Assignee: NGK Insulators Ltd
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Filing: 1995-03-31
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Granted: —
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Expires: 2015-03-31
Abstract
Abstract A sensor element for detecting solid particles in a fluid includes: a detecting unit (20) including a piezoelectric film (22) consisting essentially of a ceramic material, a first electrode (24) coated onto at least a portion of the outer surface of the piezoelectric film, and a second electrode (26) coated onto at least a portion of the inner surface of the piezoelectric film; a vibrating portion (14) consisting essentially of a second ceramic material, the detecting unit being placed on the vibrating portion so that the second electrode is coated onto at least a portion of the vibrating portion; and a fixing portion for fixing the vibrating portion so that the vibrating portion may vibrate. At least one of the detecting unit and the vibrating portion contacts with a solid particle in the fluid so that the piezoelectric film converts the vibration into an electric signal. A particle sensor includes the sensor element. The sensor element and the particle sensor are excellent in particle detection precision and durability at low cost.
Inventors
- 👤 Kazuyoshi c/o NGK Insulators Ltd. Shibata
- 👤 Yukihisa C/O Ngk Insulators Ltd. Takeuchi
- 👤 Eric J. c/o SRI Int. Shrader
- 👤 Joseph S. c/o SRI Int. Eckerle
- 👤 Ronald E. c/o SRI Int. Pelrine
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 13:29
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/04; G01N29/045; G01N29/046; B; B06; B06B; B06B1/00; B06B1/02; B06B1/06; B06B1/0644; G01N2291/00; G01N2291/02; G01N2291/022; G01N2291/0226; G01N2291/024; G01N2291/02408; G01N2291/02416
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
50 words
A sensor element for detecting a foreign solid particle in a fluid, comprising: a vibrating portion having a sufficient mass for responding to a collision with the solid particle; and an apparatus for converting a vibration of said vibrating portion into an electric signal so as to detect the vibration.
Claim 2
Dependent Claim
103 words
A sensor element of claim 1, wherein said apparatus comprises at least one of the means for converting a vibration into an electric signal selected from the group consisting of: piezoelectric means; electromagnetic-induction means; electrical capacitance change means; means for emitting a light onto said vibrating portion and for detecting a change in the light at a portion for receiving the light; means for converting a change in an electric resistance due to a strain in a conductor into an electric signal; and means for converting a change in an electric resistance due to a strain in a semiconductor into an electric signal.
Claim 3
Dependent Claim
139 words
A sensor element for detecting a solid particle in a fluid, comprising: a detecting unit including a piezoelectric film consisting essentially of a first ceramic material, a first electrode coated onto at least a portion of the outer surface of said piezoelectric film, and a second electrode coated onto at least a portion of the inner surface of said piezoelectric film; a vibrating portion consisting essentially of a second ceramic material, said detecting unit being placed on said vibrating portion so that said second electrode is coated onto at least a portion of said vibrating portion; and a fixing portion for fixing said vibrating portion so that said vibrating portion may vibrate; wherein when said detecting unit and/or said vibrating portion contacts with a solid particle in the fluid, said piezoelectric film converts the vibration into an electric signal.
Claim 4
Dependent Claim
46 words
A sensor element of claim 3, wherein said vibrating portion and said fixing portion are portions of a ceramic substrate having a unitary structure, and said ceramic substrate is formed with a cavity so that said vibrating portion has a plate shape having a small thickness.
Claim 5
Dependent Claim
50 words
A sensor element of claim 3, wherein said first ceramic material comprises at least one species selected from the group consisting of lead zirconate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, lead manganese niobate, lead antimony stanate, lead titanate, lead magnesium tungstate, lead cobalt niobate, and barium titanate.
Claim 6
Dependent Claim
14 words
A sensor element of claim 1 or 3, wherein the fluid comprises a lubricant.
Claim 7
Dependent Claim
32 words
A sensor element of claim 3, wherein said piezoelectric film has a thickness ranging from 1 to 100 micrometers, and said vibrating portion has a thickness ranging from 1 to 100 micrometers.
Claim 8
Dependent Claim
16 words
A sensor element of claim 1 or 3, wherein said vibrating portion comprises stabilized zirconium oxide.
Claim 9
Dependent Claim
142 words
A sensor, comprising: a sensor element, comprising a detecting unit including a piezoelectric film consisting essentially of a first ceramic material, a first electrode coated onto at least a portion of the outer surface of said piezoelectric film, and a second electrode coated onto at least a portion of the inner surface of said piezoelectric film; a vibrating portion consisting essentially of a second ceramic material, said detecting unit being placed on said vibrating portion so that said second electrode is coated onto at least a portion of said vibrating portion; and a fixing portion for fixing said vibrating portion so that said vibrating portion may vibrate; wherein when said detecting unit and/or said vibrating portion contacts with a solid particle in the fluid, said piezoelectric film converts the vibration into an electric signal; and a protection cover covering said detecting unit.
Claim 10
Dependent Claim
49 words
A method for detecting a solid particle in a fluid, wherein a sensor element of claim 1 or 3 is moved in relation to the fluid to be tested so that a foreign solid particle in the fluid to be tested is caused to collide with said vibrating portion.
References Cited (Backward Citations)
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