Ngk Insulators, Inc.

Miyoshi Makino

Koichi Masuda

Yosuke Adachi

Nobukazu Ikoma

Kenji Isaka

Takehiro Koganei

In a gas sensor, a powder compact seals a void space between an inner peripheral surface of metal-made main hardware and a sensor element, and the inner peripheral surface has arithmetic average roughness of 0.5 to 5 &#x3bc;m. The gas sensor includes supporters, which are arranged in a penetration hole of the main hardware, which allow the sensor element to penetrate therethrough, and which press the powder compact in sandwiching relation from both sides in an axial direction. A surface of at least one of the supporters has the arithmetic average roughness of not more than 0.5 &#x3bc;m.

Gas sensor

In a main metal pieceand an inner cylinderserving as cylindrical bodies before welding, a second end surfaceis an inclined surface that inclines toward an end portion opposite from the second end surfaceas the second end surfaceextends toward the center axis, and an angle &#x3b8;is 5&#xb0; to 15&#xb0;. Thus, the distance between a first end surfaceand the second end surfacepositioned in resistance welding increases toward the center axis, and an angle &#x3b8;c (=angle &#x3b8;) between the first end surfaceand the second end surfaceis 5&#xb0; to 15&#xb0;.

Production method for welded body and production method for gas sensor

In a gas sensor, a powder compactseals a void space between an inner peripheral surfaceof metal-made main hardwareand a sensor element, and the inner peripheral surfacehas arithmetic average roughness Ra of 0.5 to 5 &#x3bc;m. The gas sensorincludes supportersand, which are arranged in a penetration hole of the main hardware, which allow the sensor elementto penetrate therethrough, and which press the powder compactin sandwiching relation from both sides in an axial direction. A surface of at least one of the supportersandhas the arithmetic average roughness Ra of not more than 0.5 &#x3bc;m.

Among first and second swaged sections, the second swaged section begins to be swaged prior to the first swaged section. Hence, a strong force can be prevented from acting on a rubber plug in a free state at a time and the first swaged section can begin to be swaged in such a state that a portion of the rubber plug that corresponds to the second swaged section is aligned as compared to the case where the first and second swaged sections begin to be simultaneously swaged. This prevents the position of the rubber plug from being significantly varied during swaging and also prevents the rubber plug from protruding from an outer tube.

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Nagoya, Japan

Miyoshi Makino