Abstract: Provided is a gas sensor including a housing made of metal through which a sensor element is inserted and an outer cylinder made of metal welded to an outer periphery of the housing, in which generation of pinholes on a surface of a welded portion is suppressed. In a gas sensor according to one aspect of the present invention, a contact distance Lg, which is a length in an axial direction of an outer peripheral surface of a housing in contact with an inner peripheral surface of an outer cylinder on a rear end side with respect to a molten portion of the outer cylinder formed by welding, is equal to or less than a reference distance Lr.

Abstract: A gas sensor includes: a sensor element including a sensing part on one end portion thereof; a casing; and a connector disposed in the casing to electrically connect the sensor element to an outside, wherein the casing includes: an outer tube including a main portion in which a reference gas is included and a sealing portion with a diameter smaller than the main portion so that another end portion of the sensor element protrudes to the main portion; a rubber seal member fitted into the sealing portion; and a spacer intervening between the seal member and the connector, and the spacer is secured by being sandwiched between the connector and the seal member due to friction force acting on a contact surface with the seal member which occurs by that load acts on the spacer from the seal member in accordance with reduction in the diameter by swaging.

Abstract: A gas sensor includes: a sensor element including a sensing part on a side of one end portion thereof; a casing; and a connector disposed in the casing to electrically connect the sensor element to an outside, wherein the casing includes: an outer tube including a main portion in which a reference gas is included and a sealing portion being an end portion having a smaller diameter than the main portion, another end portion of the sensor element protruding to the main portion, a rubber seal member fitted into the sealing portion to seal the outer tube, and a spacer intervening between the seal member and the connector in the outer tube. The spacer includes a concave portion in an end surface on a side having contact with the connector, and has contact with the connector in the end surface except for the concave portion.

Abstract: A gas sensor for sensing a predetermined gas component contained in a measurement gas includes: a sensor element including a sensing part on one end portion thereof; a casing in which the sensor element is contained and secured; and a connector disposed in the casing, wherein the casing includes: an outer tube including a main portion in which a reference gas is included and a sealing portion as an end portion with a diameter smaller than the main portion so that another end portion of the sensor element protrudes to the main portion, a rubber seal member fitted into the sealing portion to seal the outer tube, and a spacer intervening between the seal member and the connector, and the spacer includes: a resin first spacer contacting with the seal member and having higher heat resistance than the seal member and a ceramic second spacer contacting with the connector.

Abstract: A gas sensor for sensing a predetermined gas component contained in a measurement gas includes: a sensor element including a sensing part on a side of one end portion thereof; and a casing in which the sensor element is contained and secured, including: an outer tube including a main portion in which a reference gas is present and into which the other end portion of the sensor element protrudes and a sealing portion being an end portion having a smaller diameter than the main portion; and a first seal member and a second seal member fit into the sealing portion in a two-tiered configuration to seal the outer tube, the first seal member is made of rubber, and the second seal member is made of resin more heat resistant than the first seal member, and is disposed closer to the sensor element than the first seal member is.