Ngk Insulators, Inc.

Masashi Yasui

Yusuke Watanabe

Takao Murase

Rui Sakaguchi

A heater section includes a plate-like ceramic body (a first substrate layer, a second substrate layer, and a third substrate layer) having a longitudinal direction (front-rear direction) and a short-length direction (left-right direction), and a heaterdisposed within the plate-like ceramic body and including a lead sectionand a heating sectionconnected to the lead section. The heating sectionincludes a straight portionextending along the longitudinal direction, and a lead side curved portionconnected to one of the ends of the straight portioncloser to the lead section. The lead side curved portionhas a lower resistance per unit length than the straight portionat one or more temperatures in the range of 700&#xb0; C. to 900&#xb0; C.

Ceramic heater, sensor element, and gas sensor

The heaterof the heater portion includes the linear portionsand the bend portions. A resistance value per unit length of the bend portionsat least at a temperature within a temperature range of no less than 700&#xb0; C. and no more than 900&#xb0; C. is lower than a resistance value per unit length of the linear portions

A gas sensorincludes a tubular protective coverhaving an element chambertherein and configured to allow a measured gas to flow from the outside into the element chamber; and a long sensor elementincluding a detecting portionlocated in the element chamberand configured to detect a specified gas concentration in the measured gas. An inclination angle &#x3b8;t of an axial direction of the sensor element(i.e., a direction parallel to an element axis A) in the element chamberwith respect to an axial direction of the protective cover(i.e., a direction parallel to a cover axis A) is 1&#xb0; or greater.

Gas sensor

A heating elementof a heater section includes an inner region, having a lower resistance per unit length than an outer regionat one or more temperatures in the range of 700&#xb0; C. to 900&#xb0; C.

A gas sensorincludes a tubular protective coverhaving an element chambertherein and configured to allow a measured gas to flow from the outside into the element chamber. The gas sensoralso includes a long sensor element, including a detecting portionlocated in the element chamberand configured to detect a specified gas concentration in the measured gas, and an insulatorhaving an inclined through-hole into which the sensor elementis inserted. An inclination angle &#x3b8;t of an axial direction of the sensor element(i.e., a direction parallel to an element axis A) in the element chamberwith respect to an axial direction of the protective cover(i.e., a direction parallel to a cover axis A) is 1&#xb0; or greater.

A heaterof a heater portion includes linear portionsand bend portions. A resistance value per unit length of the bend portionsat least at a temperature within a temperature range of no less than 700&#xb0; C. and no more than 900&#xb0; C. is lower than a resistance value per unit length of the linear portions

Provided is a gas sensor in which a protective cover has no looseness even by repetitive use. The gas sensor includes a sensor element for detecting a predetermined measurement target gas component in a measurement gas; a protective cover which protects a side of one end portion of the sensor element; and a housing which houses the sensor element. The protective cover includes a brim portion at one end portion of an outer surface of the protective cover. The brim portion is brought into contact with a contact surface provided in said housing, and is held between a swaging portion and the contact surface, the swaging portion extending from the contact surface while bending, so that the protective cover is fixed to the housing. The brim portion is tilted at a tilt angle of 5&#xb0; or more and 15&#xb0; or less relative to a plane vertical to a central axis of the gas sensor.

Growing community of inventors

Nagoya, Japan

Masashi Yasui