The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 06, 2006
Filed:
Aug. 20, 2001
Itsuhei Ogata, Nishio, JP;
Masanori Yamada, Nishio, JP;
Eturo Yasuda, Nishio, JP;
Kaoru Kuzuoka, Toyota, JP;
Itsuhei Ogata, Nishio, JP;
Masanori Yamada, Nishio, JP;
Eturo Yasuda, Nishio, JP;
Kaoru Kuzuoka, Toyota, JP;
Denso Corporation, Aichi-Pref., JP;
Nippon Soken, Inc., Aichi, JP;
Abstract
The thermistor portion of a thermistor device consists of a mixed sintered body of aY(CrMn)O.bAlOmade of the perovskite-type compound Y(CrMn)Oand AlO, or a mixed sintered body of aY(CrMn)O.b(AlO+YO) made of Y(CrMn)O, AlOand YO. The mole fractions a and b have the relationships 0.05≦a<1.0, 0<b≦0.95 and a+b=1. This is required to obtain a thermistor device that has stable characteristics and exhibits a small change in its resistance value, even in a heat history from room temperature to 1000° C. or the like, and also has a resistance value of 50Ω to 100 kΩ in the temperature range from room temperature to 1000° C. The precursor compounds triethoxy yttrium, diethoxy manganese and tris (2,4-pentadiono) chromium are mixed in a mixed solvent of ethanol and isopropyl alcohol, and refluxing is performed to obtain a composite metal alkoxide solution. Then the metal salt precipitating agent of deionized water is added, the mixture is stirred and mixed and refluxing is performed to obtain a gelatinous precipitate of metallic salts containing Y, Mn and Cr. This precipitate is separated by filtration, dried and calcined to obtain powdered raw material with a composition of 38Y(CrMn)O.62YO, the same as that of a thermistor device. Thereafter, this powdered raw material is molded and sintered to obtain the thermistor device as a sintered body. Thereby, the dispersion of the resistance value of the thermistor can be reduced. An anti-reducing coating made of an anti-reducing material such as YO, AlO, YAlO, 3AlO.SiO, YSiOor the like is formed on the surface of a thermistor portion consisting of a mixed sintered body of Y(CrMn)O.YO(or Y(CrMn)O.AlO) or the like to form a thermistor device with a pair of lead wires attached. Thereby, the thermistor device exhibits resistance value stability even when subjected to a reducing atmosphere.