Ngk Spark Plug Company, Limited

Naoto Terada

Chiaki Kumada

Shunsuke Goto

Kouji Okuda

A heater comprising: a metal sheath; a heating element that is connected to the inner surface of the metal sheath at one end thereof; a center pole that is extending from an opening of the metal sheath to an interior of the metal sheath and directly or indirectly connected to the heating element; an insulating material that is packed in the interior of the metal sheath; and an elastic packing, wherein the opening of the metal sheath is closed by sealing of a gap between the metal sheath and the center pole with the elastic packing, and an axial length of a portion of the elastic packing, the portion is between the metal sheath and the center pole, is not smaller than 2.5 mm.

Heater, glow plug and water heater

A heater comprising: a cylindrical metal shell having an engagement portion, the portion having a narrowed diameter; a cylindrical heating tube comprising a closed top end, a fitting portion, a smaller diameter portion, a base end side-larger diameter portion and a top end side-larger diameter portion, wherein a base end of the heating tube protrudes into an inside of the metal shell, the fitting portion is fitted into the engagement portion in interference fit, the smaller diameter portion comprises the base end of the heating tube, the smaller diameter portion has a smaller outer diameter than an inner diameter of the engagement portion, the base end side-larger diameter portion is formed between the fitting portion and the smaller diameter portion, the base end side-larger diameter portion has an outer diameter larger than or equal to the inner diameter of the engagement portion, the top end side-larger diameter portion is formed adjacent to a top end side of the fitting portion, and the top end side-larger diameter portion has an outer diameter larger than or equal to the inner diameter of the engagement portion.

Heater and glow plug

A heater has a seal structure formed by inserting a shaft-like member into a stepped bore formed in a tubular member , and setting an O-ring on an upper surface of a stepped portion of the stepped bore , a clearance between the shaft-like member and tubular member being thereby sealed with this seal structure. A seal region is formed on the upper surface of the stepped portion of the stepped bore , and a conical introduction port portion extending divergently in the rearward direction from the seal region toward an opening of the stepped bore is provided. Moreover, a cone angle &agr; of the introduction port portion with respect to an axis L of the tubular member is set to not larger than

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Nagoya, Japan

Naoto Terada