SPARK PLUG - NGK SPARK PLUG CO

Title:

SPARK PLUG

Document Type and Number:

WIPO Patent Application WO/2012/086206

Kind Code:

A1

Abstract:

This invention addresses the problem of providing a spark plug (1) formed by securely welding a ground electrode (6) by electrical resistance welding. The spark plug (1) is formed by providing a cylindrical main body metal fitting (4) and a ground electrode (6) electrical resistance-welded to the end of the main body metal fitting (4). The spark plug (1) is characterized in that the main body metal fitting (4) has a high-hardness region (42) with a Vickers hardness of 3×102 - 5×102 Hv, and in the cross section of the high-hardness region (42) in the plane containing the axis line of the spark plug (1) and the axis line of the ground electrode (6), the length d from the weld interface on the ground electrode (6) side to the weld interface on the main body metal fitting (4) side in the load direction at the time of the electrical resistance welding is between 0.3 mm and 0.8 mm.

Inventors:

KUNO TAKEHITO (JP)
YOSHIMOTO OSAMU (JP)
TANAKA TOMOO (JP)

Application Number:

PCT/JP2011/007207

Publication Date:

June 28, 2012

Filing Date:

December 22, 2011

Export Citation:

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Assignee:

NGK SPARK PLUG CO (JP)
KUNO TAKEHITO (JP)
YOSHIMOTO OSAMU (JP)
TANAKA TOMOO (JP)

International Classes:

C22C19/03; H01T13/20; H01T13/39

Domestic Patent References:

WO2010053099A1

2010-05-14

Foreign References:

JPH0513148A	1993-01-22
JP2010108939A	2010-05-13
JP2004206931A	2004-07-22
JPH10251786A	1998-09-22

Other References: