Ceramic insulator for spark plug structure
AssigneeNgk Spark Plug Co., Ltd.
InventorsTakafumi Oshima, Shigeyasu Yamada, Kazuhiko Kozuka
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Abstract
A ceramic insulator structure for use in a spark plug is manufactured by mixing granular or powdery particles of AlN, Si3N.sub.4 or Al.sub.2 O.sub.3 with an organic binder and an auxiliary sintering agent, the average spherical diameter of the particles making up the resulting ceramic mixture being in the range 20-100 microns. The ceramic mixture is then pressed in a mold into a desired shape and sintered at a temperature of 1600.degree.-2000.degree. C.
Claims5
A spark plug structure comprising a metallic shell, a ceramic insulator positioned within the metallic shell and a center electrode placed within the ceramic insulator, said ceramic insulator comprising a front half piece extending beyond said metallic shell and having an enlarged projection head at one end and a separate rear half piece provided with a recess at one end corresponding to the projection head of said front half piece, said two half pieces being joined and bonded together upon fitting the projection head of said front half piece into the recess of said rear half piece.
Dependencies are inferred from the claim text.