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:
Jan. 18, 1977
Filed:
Apr. 30, 1975
Masami Oki, Nagoya, JA;
Masatoshi Suzuki, Kariya, JA;
Yasuo Nakamura, Kariya, JA;
Osami Kamigaito, Nagoya, JA;
Hideyuki Masaki, Nagoya, JA;
Nippondenso Co., Ltd., BOTH OF, JA;
Kabushiki Kaisha Toyota Chuo Kenkyusho, BOTH OF, JA;
Abstract
A resistor built-in spark plug comprising an insulator formed therein with an axially extending bore, a terminal nut fitted in an upper end portion of the bore, a center electrode fitted in a lower end portion of the bore, a resistor arranged in a central portion of the bore, one copper-glass electrode interposed between the resistor and the terminal nut, and another copper-glass electrode interposed between the resistor and the center electrode, such resistor being made by firing (calcining) and solidifying a resistor powder mixture consisting of 30 to 10 volume % of a principal resistor component containing tin oxide, 35 to 85 volume % of insulating ceramic filler powder of a higher electric resistivity than the principal resistor component which is selected from the group consisting of quartz glass, alumina, zircon, zirconia, silica (SiO.sub.2) and .beta.-spodumene, and 35 to 5 volume % of glass powder having a softening temperature in a range between 300.degree. and 600.degree. C. One or both of the two copper-glass electrodes may consist of two electrode layers, one copper-glass layer maintained in contact wth the resistor and having a higher copper content than the other copper-glass electrode layer.