Ngk Insulators, Inc.

Hayami Aota

Yusuke Watanabe

Shotaro Niizuma

Toshihiro Hirakawa

Kirari Takahashi

A gas sensor includes: a laminate formed of a plurality of layers including at least one layer of a solid electrolyte; a reference gas chamber formed in the laminate and containing a reference gas; and a reference electrode partially exposed in the reference gas chamber. A portion which is not exposed in the reference gas chamber, of the reference electrode is sandwiched between, among the layers, a first layer and a second layer adjacent to the first layer. When an area of the portion sandwiched between the first layer and the second layer, of the reference electrode is defined as a first area, and an area of a portion exposed in the reference gas chamber, of the reference electrode is defined as a second area, a ratio of the first area to the second area is 0.3 or more.

Gas sensor

A gas sensor includes: a laminate including at least one layer made of a solid electrolyte; a measured gas flow path formed in the laminate; and a pump electrode exposed in the measured gas flow path. In a part of a rear end side region, the pump electrode is sandwiched between a first layer and a second layer or is covered with a covering layer formed on the inner surface of the measured gas flow path. The area of a portion exposed in the measured gas flow path, of the pump electrode is 4 mmor more. The area of a portion exposed in the measured gas flow path, of the front end side region is larger than the area of a portion exposed in the measured gas flow path, of the rear end side region.

A gas sensor has a sensor element, first element pads, second element pads, first contact-point members, and second contact-point members. The sensor element has first and second surfaces that are positioned on opposite sides in a first direction. The first element pads are disposed on the first surface. The second element pads are disposed on the second surface in a quantity greater than that of the first element pads. The first and second contact-point members are connected to the first and second element pads, respectively. The width (Wt) of at least one of the second contact-point members is less than the widths (Wa-Wd) of the rest of the first and second contact-point members.

A metal terminal includes an element contacting portion which is disposed at one end of the metal terminal and is placed in contact with a sensor element, a lead wire retaining member which is disposed at another end of the metal terminal, and crimps and retains lead wires, a positioning member disposed between the one end and the other end and extending in a direction intersecting one direction, the positioning member positioning the metal terminal on a ceramic housing, and a guide member provided integrally with the positioning member at a site between the positioning member and the lead wire retaining member.

Metal terminal

A gas sensor includes: a sensor element; a plurality of element pads formed on a rear end portion of the sensor element; and a plurality of contact members holding the rear end portion of the sensor element and electrically connected respectively to the plurality of element pads. The plurality of contact members include contact members that each have an outer end surface protruding out from a corresponding one of end surfaces of the sensor element.

The probability of a heater portion of a sensor element being exposed to water is lowered. The sensor element includes a built-in heater that extends in a longitudinal direction and a surrounding housing extending in the longitudinal direction. The heater includes a heat generation portion and a lead portion. The heat generation portion has a front end and a rear end, and is positioned on the same side as a front end portion side of the sensor element. The housing includes an enlarged diameter portion having a diameter of an inner wall that increases in a direction toward the front end of the sensor. The enlarged diameter portion includes a front end portion and a rear end portion. The rear end of the heat generation portion is located closer to the front end of the sensor than the rear end portion of the enlarged diameter portion is.

Sensor

A gas sensor includes: a sensor element; a plurality of element pads formed on a rear end portion of the sensor element; and a plurality of contact members holding the rear end portion of the sensor element and electrically connected respectively to the plurality of element pads. At least one contact member of the plurality of contact members has an end portion having a smaller width Wt than the other contact members.

A gas sensor includes a sensor element, an elastic insulating member, a plurality of lead wires, a plurality of metal terminals, and a ceramic housing. The plurality of lead wires are inserted in the elastic insulating member. The plurality of metal terminals each have a first end electrically connected to the sensor element, and a second end electrically connected to a corresponding one of the plurality of lead wires. The ceramic housing includes a plurality of insertion portions each including a through hole in which a corresponding one of the plurality of metal terminals is inserted, and at least one of the plurality of insertion portions has a different height from other insertion portions.

A gas sensor includes: a sensor element; a ceramic housing holding a rear end portion of the sensor element and provided with metal terminals electrically connected to the sensor element; and an elastic insulating member that is fixed in the rear of the sensor element and into which a plurality of lead wires electrically connected to the metal terminals are inserted. The elastic insulating member has one or more common spaces formed in a surface of the elastic insulating member that faces the ceramic housing. Two or more of the lead wires are arranged in each common space.

A gas sensor includes a sensor element, a tubular body made of metal, and a sealing material. The sensor element has a surface. The tubular body has a through hole which is formed along the axial direction and through which the sensor element is inserted. The sealing material is placed inside the through hole and between the inner peripheral surface of the through hole and the sensor element. The sealing material covers a part of the surface of the sensor element. When the sensor element is viewed in cross section from a second direction perpendicular to a first direction corresponding to the longitudinal direction of the sensor element, the sealing material forms a first inclination angle of not less than 10&#xb0; and not more than 80&#xb0; with respect to the surface.

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Nagoya, Japan

Hayami Aota