US 12,080,997 B2
Spark plug
Susumu Imai, Nagoya (JP); and Tatsuya Gozawa, Nagoya (JP)
Assigned to Niterra Co., Ltd., Nagoya (JP)
Appl. No. 18/559,754
Filed by Niterra Co., Ltd., Nagoya (JP)
PCT Filed Jun. 6, 2022, PCT No. PCT/JP2022/022751
§ 371(c)(1), (2) Date Nov. 8, 2023,
PCT Pub. No. WO2023/281956, PCT Pub. Date Jan. 12, 2023.
Claims priority of application No. 2021-113908 (JP), filed on Jul. 9, 2021.
Prior Publication US 2024/0243556 A1, Jul. 18, 2024
Int. Cl. H01T 13/34 (2006.01)
CPC H01T 13/34 (2013.01) 4 Claims
OG exemplary drawing
 
1. A spark plug comprising:
an insulator having an axial hole extending in an axial direction;
a center electrode disposed in the axial hole and having a forward end portion projecting to a forward end side of the axial hole;
a tubular metallic shell which holds the insulator on its inner circumferential side and has a screw portion formed on its outer circumferential surface; and
a ground electrode whose first end portion is inserted into a through hole provided in the metallic shell and is welded to the through hole and whose second end portion forms a discharge gap between the second end portion and the forward end portion of the center electrode,
wherein the screw portion has a first screw portion located on a rear end side of the through hole in the axial direction and a second screw portion located on a forward end side of the through hole in the axial direction, and
the second screw portion has a pitch diameter larger than a pitch diameter of the first screw portion.