Spark plug

摘要

A spark plug includes a tubular insulator, a center electrode, a tubular metal shell, a ground electrode, and a pillar body tip. The tubular insulator has an axial hole penetrating in the direction of an axis. The pillar body tip includes one end face that is welded to the ground electrode and another end face that forms a gap with a front end portion of the center electrode. The ground electrode includes a part where the tip is to be welded. The surface forms a clearance with a part including a constituent material of the tip. The ground electrode includes a surface where a plating layer is disposed. The plating layer covers a surface excluding a formation part of the clearance. The clearance has a size A that is equal to or more than 0.01 mm and equal to or less than 0.5 mm.

主权项

1. A spark plug comprising:
a tubular insulator having an axial hole penetrating in a direction of an axis; a center electrode inserted into a tip end side of the axial hole; a tubular metal shell disposed at an outer circumference of the insulator; a ground electrode disposed at a front end portion of the metal shell; and a pillar body tip that includes one end face and another end face, the one end face being welded to the ground electrode, the other end face forming a gap with a front end portion of the center electrode, wherein the ground electrode includes a part where the tip is to be welded, a clearance formed between a plating layer and a part including a constituent material of the tip; the ground electrode includes a surface where the plating layer is disposed, the plating layer covering the surface excluding a formation part of the clearance in the surface of the ground electrode; and the clearance has a size A that is equal to or more than 0.01 mm and equal to or less than 0.5 mm.