US 12,009,639 B2
Spark plug
Takashi Sekizawa, Nagoya (JP); Tomokatsu Kashima, Nagoya (JP); Yuya Ono, Nagoya (JP); Yuki Toumatsu, Nagoya (JP); Yudai Kawaguchi, Nagoya (JP); and Kazuyoshi Torii, Nagoya (JP)
Assigned to NGK SPARK PLUG CO., LTD, Nagoya (JP)
Appl. No. 17/437,679
Filed by NGK SPARK PLUG CO., LTD., Nagoya (JP)
PCT Filed Nov. 17, 2020, PCT No. PCT/JP2020/042783
§ 371(c)(1), (2) Date Sep. 9, 2021,
PCT Pub. No. WO2021/106681, PCT Pub. Date Jun. 3, 2021.
Claims priority of application No. 2019-217461 (JP), filed on Nov. 29, 2019.
Prior Publication US 2022/0166196 A1, May 26, 2022
Int. Cl. H01T 13/32 (2006.01); H01T 13/06 (2006.01); H01T 21/02 (2006.01)
CPC H01T 13/32 (2013.01) [H01T 13/06 (2013.01); H01T 21/02 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A spark plug comprising:
a center electrode;
a metal shell insulating and holding the center electrode; and
a ground electrode including a base material having one end portion connected to the metal shell, and a tip connected to another end portion of the base material, wherein
the tip has a discharge surface opposed to the center electrode with a spark gap therebetween,
the discharge surface has a quadrangular shape and is chamfered at four sides thereof, and
only a first side which is one of the four sides is provided with a C chamfer.