SPARK PLUG - NGK SPARK PLUG CO

Title:

SPARK PLUG

Document Type and Number:

WIPO Patent Application WO/2012/172712

Kind Code:

A1

Abstract:

For a spark plug having an electrode comprising a coated section and a core section, a gap is prevented form being created between the coated section and the core section. The spark plug has a center electrode and a ground electrode that forms a gap with the center electrode. At least the center electrode or the ground electrode has a coated section and a core section that is covered by the coated section and is made of a material having a different thermal expansion coefficient from that of the coated section. A concave section and a convex section are formed on the apical part of the core section. In a cross-section that extends through the center of gravity of the apical surface of the electrode and extends through the convex sections, the area of the convex section, which extends through the point 0.2mm point from the apex of the convex section in the direction of the bisector of the convex section and is surrounded by a line which is perpendicular to the bisector, is smaller than the area of the triangle that is formed by connecting the apex of the convex section with the intersecting points of the outline of the convex section and the line perpendicular to the bisector.

Inventors:

KATO TOMOAKI (JP)

Application Number:

PCT/JP2012/001561

Publication Date:

December 20, 2012

Filing Date:

March 07, 2012

Export Citation:

Click for automatic bibliography generation Help

Assignee:

NGK SPARK PLUG CO (JP)
KATO TOMOAKI (JP)

International Classes:

H01T13/20; F02P13/00; H01T13/16

Foreign References:

JP2008130463A	2008-06-05
JPH0737678A	1995-02-07
JPS60142487U	1985-09-20
JPH04206376A	1992-07-28
JP2008130463A	2008-06-05

Other References: