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(11) | EP 1 519 460 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method for producing a spark plug and spark plug |
| (57) A method for producing a spark plug, the spark plug including: a center electrode;
an insulator which holds the center electrode therein in a state where a tip end portion
of the center electrode protrudes therefrom; a metal shell which holds the insulator
therein; a ground electrode which is fixed to the metal shell, the ground electrode
having an inner side face having a width that is smaller as it advances toward a tip
end side, in a portion of the inner side face positioned between a pair of tapered
faces; and a discharge portion which is bonded to the inner side face of the ground
electrode by laser welding so as to attain a diameter of 0.8 mm or less and a height
of 0.5 mm or more, a discharge gap being formed between the discharge portion and
the tip end portion of said center electrode, the method including: forming the tapered
faces before the discharge portion is laser-welded to the inner side face.
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