Title:
SPARK PLUG
Document Type and Number:
WIPO Patent Application WO/2016/208128
Kind Code:
A1
Abstract:
The purposes of the present invention are to reduce capacitance, and to ensure impact resistance of a central electrode. This spark plug is provided with a main metal fitting, an insulator, a resistor, a central electrode, and a seal body. The main metal fitting is a substantially cylindrical member having a ground electrode provided to the tip side. The insulator is a cylindrical member which is held inside the main metal fitting, and which has, provided therein, an axial hole provided with: a small-diameter section; an intermediate-diameter section which has a larger diameter than the small-diameter section, and which is connected to the rear end of the small-diameter section via a stepped section; and a large-diameter section which has a larger diameter than the intermediate-diameter section, and which is disposed further towards the rear-end side than the intermediate-diameter section. The resistor has at least a portion thereof disposed inside the large-diameter section. The central electrode is provided with: a flange section which protrudes in the radial direction inside the intermediate-diameter section, and comes into contact with the stepped section; and a leg section which extends from the flange section to the tip side, and which is disposed inside the small-diameter section. The seal body is an electrically conductive member which is disposed further towards the rear-end side than the stepped section, and which electrically connects the central electrode and the resistor. The rear end of the seal body is positioned inside the intermediate-diameter section.
Inventors:
UEGAKI HIRONORI (JP)
NAKANO SEIJI (JP)
KURONO HIROKAZU (JP)
NAKANO SEIJI (JP)
KURONO HIROKAZU (JP)
Application Number:
PCT/JP2016/002666
Publication Date:
December 29, 2016
Filing Date:
June 02, 2016
Export Citation:
Assignee:
NGK SPARK PLUG CO (JP)
International Classes:
H01T13/34; H01T13/20
Foreign References:
| JP2009541916A | 2009-11-26 | |||
| JPS58189917A | 1983-11-05 | |||
| JP2015099765A | 2015-05-28 |
Other References:
See also references of EP 3312954A4
Attorney, Agent or Firm:
AOKI, Noboru et al. (JP)
Aoki 昇 (JP)
Aoki 昇 (JP)
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