SPARK PLUG MANUFACTURING METHOD

Title:

SPARK PLUG MANUFACTURING METHOD

Document Type and Number:

WIPO Patent Application WO/2012/120757

Kind Code:

A1

Abstract:

The objective of the present invention is to provide a spark plug manufacturing method that allows, by detecting the presence of a defect of an insulator, a spark plug with an insulator that exhibits a withstand voltage performance to be provided. This spark plug manufacturing method is characterized by involving a step in which an assembly comprising a center electrode, a main metal fitting, and the insulator is placed inside a pressure-resistant container; the pressure inside the pressure-resistant container is brought to an ambient pressure higher than the barometric pressure; and a potential difference is created between the center electrode and the main metal fitting with an insulating oil being present inside a space where the insulating oil is allowed to be present, which being a space surrounded by a packing, the main metal fitting, the insulator, and a virtual plane including the front end surface of the main metal fitting, at least at the position where the distance between a shelf section and the insulator becomes the minimum in order to determine whether or not a defect is present in the insulator.

Inventors:

HIROSE KAZUMICHI (JP)
KURONO HIROKAZU (JP)
HONDA TOSHITAKA (JP)

Application Number:

PCT/JP2012/000145

Publication Date:

September 13, 2012

Filing Date:

January 12, 2012

Export Citation:

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Assignee:

NGK SPARK PLUG CO (JP)
HIROSE KAZUMICHI (JP)
KURONO HIROKAZU (JP)
HONDA TOSHITAKA (JP)

International Classes:

H01T13/60; H01T21/02

Foreign References:

JPS3920383B1
JP2009238667A	2009-10-15
JP2004108817A	2004-04-08
DE102007024407A1	2008-11-27
JP2550790B2	1996-11-06
JP2004108817A	2004-04-08

Other References: