(19)
(11) EP 2 410 243 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
09.01.2013 Bulletin 2013/02

(43) Date of publication A2:
25.01.2012 Bulletin 2012/04

(21) Application number: 11174774.7

(22) Date of filing: 21.07.2011
(51) International Patent Classification (IPC): 
F23Q 7/00(2006.01)
(84) Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME

(30) Priority: 21.07.2010 JP 2010164239
06.07.2011 JP 2011149791

(71) Applicant: NGK Spark Plug Co., Ltd.
Nagoya-shi, Aichi 467-8525 (JP)

(72) Inventors:
  • Kumagai, Kenichi
    Nagoya, Aichi (JP)
  • Okada, Hirofumi
    Nagoya, Aichi (JP)
  • Ishii, Shuei
    Nagoya, Aichi (JP)

(74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser 
Leopoldstrasse 4
80802 München
80802 München (DE)

   


(54) Glow Plug


(57) [Problem] To provide a glow plug with which it is possible to improve heat resistance and durability in comparison with a heretofore known one.
[Means for Resolution] A glow plug uses a sheathed heater with a heating coil housed in a sheath tube. The sheath tube, being formed from a nickel base alloy containing 21 to 30 percent by mass of chromium (Cr), 0.05 to 0.30 percent by mass of carbon (C), 1.0 to 2.4 percent by mass of aluminum (Al), and 0.1 to 0.3 percent by mass of one kind or more among titanium (Ti), zirconium (2r), and niobium (Nb), is such that when examining a metal structure in a circumferential transverse section of the sheath tube, the size of the metal structure has a variation of 2 or less in crystal grain size number according to JIS G0551 (2005), and Vickers hardness is within a range of 200 to 400.







Search report









Search report