(19)
(11) EP 2 899 286 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
17.02.2016 Bulletin 2016/07

(43) Date of publication A2:
29.07.2015 Bulletin 2015/31

(21) Application number: 15151035.1

(22) Date of filing: 14.01.2015
(51) International Patent Classification (IPC): 
C22C 19/05(2006.01)
C22C 38/18(2006.01)
F23Q 7/22(2006.01)
H05B 3/48(2006.01)
 C22C 38/06(2006.01)
F23Q 7/00(2006.01)
H05B 3/00(2006.01)
H05B 3/50(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: 15.01.2014 JP 2014004904
25.12.2014 JP 2014262488

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

(72) Inventors:
  • Yatsuya, Yosuke
    Nagoya, Aichi (JP)
  • Segawa, Masayuki
    Nagoya, Aichi (JP)
  • Tanaka, Tomo-o
    Nagoya, Aichi (JP)

(74) Representative: Grünecker Patent- und Rechtsanwälte PartG mbB 
Leopoldstraße 4
80802 München
80802 München (DE)

   


(54) Sheated heater, glow plug


(57) [Objective] To improve durability of a sheath heater.
[Means for Solution] A sheath heater includes a sheath tube, a heating unit, and a magnesium oxide. The sheath tube is a tubular member whose one end is closed.
The heating unit generates heat by transmission of electricity and is arranged inside the sheath tube. The magnesium oxide is arranged between the sheath tube and the heating unit and filled directly in contact with the sheath tube. The sheath tube is not thermally contracted when a temperature is increased from 20°C to 1200°C. In the sheath tube, an average thermal expansion rate is equal to or more than 13 × 10-6/K and equal to or less than 18 × 10-6/K when the temperature is increased from 20°C to 1200°C.







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Search report