Patent ID: 7615915
Filing Date: 2009-11-10
Classification: H01T

Abstract:
1. A spark plug comprising: an insulator having an axial hole formed in an axial direction along an axis of said spark plug; a center electrode disposed in said axial hole of said insulator and on a leading end side of said axial hole; a metal shell surrounding said insulator; and a ground electrode including a ground electrode body having a first end joined to said metal shell, and a first precious metal tip formed in a second end portion of said ground electrode body so that a leading end surface of said first precious metal tip is disposed opposite said center electrode, wherein: said ground electrode further includes a molten portion between said first precious metal tip and said ground electrode body; said first precious metal tip is laser-welded to an inner circumferential surface of said ground electrode body to form said molten portion in a condition such that a shortest distance D said molten portion extends to said second end surface of said ground electrode body; and said shortest distance D