SPARK PLUG - NGK SPARK PLUG CO

Title:

SPARK PLUG

Document Type and Number:

WIPO Patent Application WO/2013/011723

Kind Code:

A1

Abstract:

This spark plug (1) is provided with: a center electrode (5); a ground electrode (27); and a tip (31) that is joined to the center electrode (5) and forms a spark discharge gap (33) between the tip and the ground electrode (27). The tip (31) is joined to the center electrode (5) via a fused section (35). The fused section (35) has bare surfaces (35E) that are exposed to the open air. In a cross-section that includes the axis line (CL1) and runs through the center (CP) of a bare surface (35E), when C (mm) denotes the distance between the apex of the tip (31) and the fused section (35) in a side surface of the tip (31) and B (mm) denotes the distance between the apical surface (31F) of the tip (31) and the part of the fused section (35) that is located closer to the axis line (CL1) than to the side surface of the tip (31) and that is closest to the apical surface (31F) of the tip (31), C - B ≥ 0.02 is satisfied. Consequently, emergence of the fused section (35) to the spark discharge gap (33) side can be prevented for a long time, so the durability can be improved.

Inventors:

KATSURAYA KOHEI (JP)
NAKAYAMA KATSUTOSHI (JP)

Application Number:

PCT/JP2012/059761

Publication Date:

January 24, 2013

Filing Date:

April 10, 2012

Export Citation:

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Assignee:

NGK SPARK PLUG CO (JP)
KATSURAYA KOHEI (JP)
NAKAYAMA KATSUTOSHI (JP)

International Classes:

H01T13/20; F02P13/00; H01T13/39

Domestic Patent References:

WO2009037884A1

2009-03-26

Foreign References:

JP2006128076A	2006-05-18
JP2002216932A	2002-08-02
JP2000208235A	2000-07-28
JP2003068421A	2003-03-07
JP2006236906A	2006-09-07

Other References: