Title:
スパークプラグ
Document Type and Number:
Japanese Patent JP6422841
Kind Code:
B2
Abstract:
To provide a technology that can render an insulator less easily breakable when an axial hole 2 of the insulator is filled with the material of an electrically-conductive seal portion without fixing the position of a tapered portion of the electrically-conductive seal portion to an inside of a flange portion of the insulator. An electrically-conductive seal portion 60 of a spark plug 1 includes a large-diameter seal portion 65, a small-diameter seal portion 67 having an outer diameter smaller than an outer diameter of the large-diameter seal portion, and a tapered seal portion 66 disposed between the large-diameter seal portion and the small-diameter seal portion. An insulator 3 includes a flange portion 31, a first middle-body portion 32 having an outer diameter smaller than an outer diameter of the flange portion, a second middle-body portion 34 having an outer diameter smaller than an outer diameter of the first middle-body portion, and a leg portion 37 having an outer diameter that tapers toward a tip end of the spark plug. The tapered seal portion is disposed inside the first middle-body portion.
Inventors:
Hironori Uegaki
Ichizaki Kichi
Ichizaki Kichi
Application Number:
JP2015206140A
Publication Date:
November 14, 2018
Filing Date:
October 20, 2015
Export Citation:
Assignee:
Nippon Special Ceramics Co., Ltd.
International Classes:
H01T13/20
Domestic Patent References:
| JP2002530842A | ||||
| JP2015176687A | ||||
| JP4167385A | ||||
| JP50005740A |
Attorney, Agent or Firm:
Meisei International Patent Office