Niterra Co., Ltd.

Takaaki Kikai

Daisuke Sumoyama

Kengo Hattori

Kaito Nakamura

Satoshi Noguchi

A spark plug which is reduced in consumption of a discharge member, thereby having a longer service life. This spark plug is provided with: a first electrode that comprises a discharge member; and a second electrode that faces the discharge member, with a spark gap lying therebetween. The discharge member is mainly composed of Ru, while containing 0.5% by mass to 30% by mass of Ni or Co.

Spark plug

To provide a spark plug that can ensure the strength of a melt portion, the spark plug includes: a center electrode; a metal shell in which the center electrode is insulated and held, the metal shell including a cylindrical portion having an outer circumference provided with an external thread, the metal shell further including a hole penetrating the cylindrical portion in a radial direction; and a ground electrode protruding from the metal shell toward the center electrode and connected, in the hole, to the cylindrical portion via a melt portion. In a cross section including a center line of the hole and the melt portion, the melt portion has a part in contact with the cylindrical portion, and the part is present on an outer side in the radial direction relative to the ground electrode.

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Nagoya, Japan

Takaaki Kikai