| 摘要 |
A spark plug wherein an outer diameter of a first face that is a gap foliating face of the center electrode tip is denoted as R1, an outer diameter of a second face that is a gap forming face of the ground electrode tip is denoted as R2, a length of the gap is denoted as G1, and 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 G2, R1<R2, 0.5 mm≦R1≦1.1 mm, 0.7 mm≦R2≦1.2 mm, 0.6 mm≦G1≦1.3 mm, and 1.4≦(R2/R1)×(G2/G1)≦1.8 are satisfied. |
| 主权项 |
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, wherein the center electrode is 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 and includes a ground electrode tip forming a gap between itself and the center electrode tip, wherein, in a particular cross section including a center axis of the center electrode tip, when two directions that are orthogonal to a center axis of the center electrode tip and opposed to each other are denoted as a first direction and a second direction, an outer diameter of a first face that is a face of the center electrode tip forming the gap is denoted as R1, an outer diameter of a second face that is a face of the ground electrode tip forming the gap is denoted as R2, a length of the gap is denoted as G1, and 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 G2,
R1<R2,0.5 mm≦R1≦1.1 mm,0.7 mm≦R2≦1.2 mm,0.6 mm≦G1≦1.3 mm, and1.4≦(R2/R1)×(G2/G1)≦1.8are satisfied. |
