A method for producing a spark plug

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EP 0 975 075 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	02.02.2000 Bulletin 2000/05

(43)	Date of publication A2:
	26.01.2000 Bulletin 2000/04

(21)	Application number: 99122560.8

(22)	Date of filing: 27.06.1997

(51)	International Patent Classification (IPC)⁷: H01T 21/02

(84)	Designated Contracting States:
	DE FR GB IT

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Priority:

28.06.1996 JP 18834796
28.11.1996 JP 33511996

(62)	Application number of the earlier application in accordance with Art. 76 EPC:
	97110583.8 / 0817341

(71)	Applicant: NGK SPARK PLUG CO., LTD
	Mizuho-ku Nagoya-shi Aichi (JP)

(72)	Inventors:
	Matsutani, Watarui, c/o NGK Spark Plug Co., Ltd. Nagoya-shi, Aichi (JP) Kagawa, Junichi, c/o NGK Spark Plug Co., Ltd. Nagoya-shi, Aichi (JP)

(74)	Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät
	Maximilianstrasse 58 80538 München 80538 München (DE)

(54)	A method for producing a spark plug

(57) A method for producing a spark plug comprising a central electrode, an insulator provided exterior to the central electrode, main metallic shell provided exterior to the insulator in such a way that the central electrode protrudes from one end, and a ground electrode coupled at one end to the metallic shell and which has the other end disposed to face the central electrode (3), with a chip being secured to either the central electrode or the ground electrode or both to form spark discharge gap (g). The chip is made by working an alloy including Ir based alloy, including Rh in an amount ranging from 3 wt.% to less than 50 wt.% to a chip of desired dimensions.

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