Patent ID: 9325156
Filing Date: 2016-04-26
CPC Classification: H01T

Claim Text:
1. A spark plug comprising: a center electrode including a center electrode body extending in an axial direction and a center electrode tip joined to a front end of the center electrode body; an insulator having an axial hole extending in the axial direction, the center electrode being arranged in the axial hole; a metal shell arranged around an outer circumference of the insulator; and a ground electrode including a ground electrode body electrically connected to the metal shell and a projection part that is a portion projecting toward the center electrode from an end part of the ground electrode body, the projection part including a ground electrode tip forming a gap between itself and the center electrode tip, wherein a particular cross section includes a center axis of the center electrode tip, wherein two directions that are orthogonal to the center axis of the center electrode tip and opposed to each other are denoted as a first direction and a second direction, wherein an outer diameter of a first face that is a face of the center electrode tip forming the gap is denoted as R wherein an outer diameter of a second face that is a face of the ground electrode tip forming the gap is denoted as R wherein a length of the gap is denoted as G wherein an average distance of a distance between an end in the first direction of the first face and an end in the first direction of the second face and a distance between an end in the second direction of the first face and an end in the second direction of the second face is denoted as G wherein the following is satisfied: