| 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, 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 R1, wherein an outer diameter of a second face that is a face of the ground electrode tip forming the gap is denoted as R2, wherein a length of the gap is denoted as G1, 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 G2, and wherein the following is satisfied:
R2/R1>1,R1<R2,G2/G1>1,0.5 mm≦R1≦1.1 mm,0.7 mm≦R2≦1.2 mm,1<R2/R1<1.8,0.6 mm≦G1≦1.3 mm, and1.4≦R2/R1×G2/G1≦1.8. |
