Ngk Spark Plug Company, Limited

Ngk Spark Plug., Ltd.

Kouji Okazaki

Takahiro Suzuki

Yoshiaki Matsubara

Tomoyuki Tanaka

Mamoru Kodera

A method of manufacturing a spark plug includes a joining step of joining a first member and a second member which constitute the spark plug. In the joining step, a first welding electrode in contact with the first member and a second welding electrode which has an elastically deformable intermediate portion and which is in contact with the second member are electrically connected through the first member and the second member, whereby the first member and the second member are joined together by resistance welding.

Manufacturing method for spark plug

A threaded portion is formed on a metal shell of a spark plug. Within a mounting base of the metal shell, a pressure sensor is arranged in such a direction that it generates an electrical signal in response to a variation in a tightening load of the spark plug. A slit is formed as a pressure-introducing channel along an axis of the spark plug in the threaded portion of the metal shell so that the slit is communicated with an interior of the mounting base.

Spark plug with built-in pressure sensor

A spark plug is provided with a built-in, ring-shaped pressure sensor. The pressure sensor is composed of a plate packing, a piezoelectric element, an electrode plate and an insulating plate stacked one over the other and also includes a lead wire extending from the electrode plate through a through-hole formed in an upper part of a base portion of a metal shell to output electrical signals. The pressure sensor is accommodated in a cylindrical metal casing of L-shaped cross-section and disposed above a gasket and on the base portion. The metal casing is integrally welded over an entire circumference thereof to the base portion at an upper edge and also at a lower edge, whereby the pressure sensor is sealed within the metal casing.

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Nagoya, Japan

Kouji Okazaki