| 摘要 |
The purposes of the present invention are to reduce capacitance, and to ensure impact resistance of a central electrode. A main metal fitting is a substantially cylindrical member having a ground electrode provided to the tip side. An 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, and a large-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. A resistor is disposed inside the large-diameter section. A central electrode is provided with: a flange section which protrudes in the radial direction inside the large-diameter section, and comes into contact with the stepped section; a leg section which extends from the flange section to the tip side, and which is disposed inside the small-diameter section; and a head section which extends from the flange section to the rear-end side. A seal body is an electrically conductive member which is disposed inside the large-diameter section, and which electrically connects the central electrode and the resistor. The central electrode is formed by joining an electrically conductive part comprising an electrically conductive material, and an insulating part comprising an insulating material. The seal body electrically connects the electrically conductive part and the resistor. The insulating part is provided with a protrusion positioned further towards the rear-end side than the rear end of the seal body. The protrusion is embedded in the resistor. |
