| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve spark plug durability through good thermal management of a ground electrode and enhanced local 'wear' protection of the ground electrode. <P>SOLUTION: A spark plug having a ground electrode with a precious metal pad welded to the ground electrode through a series of weld steps. The precious metal pad is a Pt-based pad which is attached to a side surface of the ground electrode via an attachment process that includes: a resistance tack weld to initially secure the pad in place; a coining step to flatten the pad; a second resistance weld to form a permanent weld of the pad to the ground electrode; and a laser capping weld about the exposed periphery of the pad to seal the resistance weld. The laser capping weld comprises numerous overlapping weld spots that together form an annular weld bead located at or just below the discharge surface of the pad. <P>COPYRIGHT: (C)2012,JPO&INPIT |
