Ngk Spark Plug Company, Limited

Takayoshi Atsumi

Yasuhiro Fujita

Hiroshi Isomura

Naoki Yamada

Koji Shiono

Yoshiyasu Fujii

Satoshi Ishikawa

Hideya Inukai

Mitsuru Sugihara

Takeo Mizui

Masamine Takagi

Takao Kojima

Hisaharu Nishio

Kouji Matsuo

Yoshiaki Matsubara

Masahiro Asai

Keita Nakagawa

Kazuhiro Kouzaki

Yuji Shimazaki

Hidekazu Kato

Toru Furuichi

Daiki Tabuchi

Aya Sato

Chihiro Seki

A gas sensor includes a metal shell, a gas sensor element held in the metal shell, a metal portion arranged between a flange portion of the gas sensor element and a seat portion of the metal shell and a porous thermal spray layer formed on the gas sensor element. When viewed in cross section along the direction of an axis of the gas sensor, a corner of the metal portion axially overlaps in position with or radially outwardly protrudes from an outer surface of a part of the thermal spray layer located on a side surface of the flange portion and is brought into contact with the seat portion. A rear end-facing surface of the metal portion is brought into contact with an outer surface of the thermal spray layer at a position radially inside the side surface of the flange portion.

Gas sensor

A protector has a two-stage structure that includes a large-diameter portion and a small-diameter portion. The large-diameter portion includes a cylindrical first peripheral wall and a first front end wall. The small-diameter portion includes a cylindrical second peripheral wall connected to the first front end wall and a second front end wall connected to a front end portion of the second peripheral wall. Opening portions are not formed in the first and second peripheral walls. First opening portions, which are opened toward only first recessed portions and an inner surface of the first peripheral wall, are formed at the first front end wall. A second recessed portion and second opening portions, which are formed in the second recessed portion and are opened toward an inner surface of the second peripheral wall, are formed in the second front end wall.

A gas sensor suppresses the deterioration of gas tightness caused by failure of a sealing material. The gas sensor includes: a housing; a sensor element arranged inside the housing; a sealing material filling a gap between the sensor element and the housing; an insulation member arranged on a proximal end side of the sealing material; and an annular metal ring arranged on a proximal end side of the insulation member. The sealing material, the insulation member and the metal ring are fixed under pressure by caulking from a proximal end side to a distal. A proximal-end facing surface of an inner peripheral portion of the metal ring is spaced apart from the caulking portion in an opposing region where an inner end of the caulking portion and the metal ring face each other in an opposed manner.

A gas sensor, including a cylindrical outer tube; and a seal member disposed in the outer tube, the seal member including: a lead wire insert hole and an atmosphere communication hole extending in an axial direction thereof. The gas sensor further includes: a protection portion which covers the atmosphere communication hole from the rear end of the gas sensor in the axial direction, the protection portion having a protrusion which protrudes toward a rear side of the gas sensor, and has an opening smaller than an opening of the atmosphere communication hole, wherein the protrusion is disposed at a further front end side of the rear end surface of the seal member.

A gas sensor, including a cylindrical outer tube; and a seal member disposed therein, the seal member including: a lead wire insert hole and an atmosphere communication hole. The seal member has a groove extending outwards in a radial direction at a rear end-facing surface from the atmosphere communication hole while circumventing the lead wire insert hole, the groove having a cutout toward the front end of the seal member. The gas sensor further includes: a protection portion which covers the atmosphere communication hole; and an arm couples the protection portion and the outer tube, and extends in the radial direction, the arm being at least partially disposed in the groove of the seal member. and the arm is disposed so as to define a gap with the bottom surface of the groove.

A gas sensor includes an inner electrode formed on an inner surface of a base body. The inner electrode has an inner sensing portion formed in a gas contact inner region such that the inner sensing portion is located on the whole of a heat-facing area of the gas contact inner region facing a heating portion in a radial direction of the base body, a terminal contact portion formed in a rear end region such that the terminal contact portion is located in at least a part of the rear end region in a circumferential direction of the base body and a lead portion formed only on a part of the inner surface of the base body in the circumferential direction of the base body so as to connect the inner sensing portion and the terminal contact portion to each other.

A sensor including a tubular casing having an open rear end; and a first elastic member having a through hole so as to introduce ambient air into the casing and disposed so as to block the rear end opening of the casing. The sensor further includes: a holding inner tube that closely contacts an inner peripheral surface of the through hole; a ventilation filter that has permeability and a waterproofing property, the ventilation filter including a filter blocking portion that blocks a rear end opening of the holding inner tube, and a filter tubular portion connected to the filter blocking portion and surrounding at least a portion of an outer peripheral surface of a rear end portion of the holding inner tube in the peripheral direction; and a holding outer tube that includes a ventilation hole, an outer tube blocking portion covering the filter blocking portion, and an outer tube tubular portion connected to the outer tube blocking portion and surrounding at least a portion of the filter tubular portion in the peripheral direction.

Sensor

A gas sensor including a detection element having a detection portion; a metal shell that surrounds the detection element so as to expose the detection portion to a measured atmosphere; an outer tube that is fixed to the metal shell so as to cover a rear end side of the detection element; and a seal member that is contained inside the outer tube, the seal member having a lead wire insertion hole and a through hole that penetrates in the axial direction; a tubular holding member made of a resin having a lower coefficient of thermal expansion than the seal member, the tubular holding member being held inside the through hole, the tubular holding member having a ventilation hole; and a filter that covers the ventilation hole, the filter being joined to the holding member, the filter blocking water from passing therethrough, and the filter having air permeability.

Gas sensor and gas sensor unit

A gas sensor has a sensor element, extending axially, that detects a particular gas component in a gas under measurement, a metal housing causing the end of the sensor element to protrude farther than the end thereof to expose it to the gas under measurement and that surrounds the periphery of the sensor element and an outer tube disposed at the rear end inside the metal housing and a seal member that is disposed farther to the rear than the detection element and also inside the rear end of the outer tube, and that has formed therein a atmosphere-introduction hole passing therethrough in the axial direction, the gas sensor further having a crimped part, formed in the outer tube, for the purpose of holding the seal member a hollow-cylindrical member in contact with the inner peripheral surface of the atmosphere-introduction hole so as to oppose the crimped part, and a metal filter that joins to the hollow-cylindrical member at the rear end of the hollow-cylindrical member and also farther to the rear than the crimped part.

A gas sensor having an axis including a detecting element; a metal shell; an outer cylinder; and a plug member, as defined herein, and the gas sensor includes a first protective member that covers an air vent of the plug member so as to protect the filter member, the protective member having a ventilation portion having an opening smaller than an opening of the air vent and at least partially overlapping the air vent in the axial direction, and at least one of the outer cylinder and the plug member is provided with a locking portion that limits rotation of the protective member around the axis.

A gas sensor having a gas sensor element which includes: a reference electrode; a solid electrolyte layer having oxygen ion conductivity; a detection electrode; and an electrode-protecting layer covering the detection electrode. The electrode-protecting layer is a porous body carrying catalytic metal, and includes: a detection electrode side portion having a catalytic metal loading ratio of more than 0% by weight and not more than 0.005% by weight; and a surface side portion provided closer to the outer surface of the electrode-protecting layer than the detection electrode side portion, the surface side portion having a catalytic metal loading ratio of 0.01% by weight or more.

Gas sensor and method for manufacturing the same

The oxygen sensor of the present invention has excellent durability capable of effectively preventing contamination with lead or the like for a detection electrode even in low temperature exhaust gases, and having stable response over a long period of time. The contamination preventive layer provided in the sensor device comprises composite powders having coarse powders covered therearound with fine powders, and hollows not filled with fine powders are scattered in gaps among the composite powders. Both the coarse and fine powders comprise ceramic powders. Further, it is particularly preferred that the ceramic powders are powders of a titania powder having a peak at 1 &#x3bc;m or less and a composite ceramic powder containing alumina such as spinel having a peak at 10 &#x3bc;m or more. The contamination preventive layer can be formed by coating a slurry containing ceramic powders of different specific surface areas, an organic binder and a solvent such as methanol on the surface of the electrode protection layer followed by drying.

Oxygen sensor and a manufacturing method of the sensor device

A gas sensor is provided which comprises a sensor element for detecting a component of a gas and a cup-shaped protector for covering a detecting section of the sensor element. The protector is dual-walled and have cup-shaped inner and outer protector members. The inner and outer protector members are constructed and arranged so that g >g where g is the distance between an inner surface of a circumferential wall of the outer protector member and an outer surface of a circumferential wall of the inner protector member and g is the distance between an inner surface of a bottom wall of the outer protector member and an outer surface of a bottom wall of the inner protector member. The outer protector member has at the circumferential wall thereof a plurality of first gas holes. The inner protector member has at the circumferential wall thereof a plurality of second gas holes.

A gas sensor is provided which comprises a sensor element for detecting a component of a gas and a cup-shaped protector for covering a detecting section of the sensor element. The protector is dual-walled and have cup-shaped inner and outer protector members. The inner and outer protector members are constructed and arranged so that g1>g2 where g1 is the distance between an inner surface of a circumferential wall of the outer protector member and an outer surface of a circumferential wall of the inner protector member and g2 is the distance between an inner surface of a bottom wall of the outer protector member and an outer surface of a bottom wall of the inner protector member. The outer protector member has at the circumferential wall thereof a plurality of first gas holes. The inner protector member has at the circumferential wall thereof a plurality of second gas holes. When the direction of a tip end of the sensor element is referred to as forward, the first gas holes are disposed forward of the second gas holes. A front end of the sensor element is disposed forward of the second gas holes. The inner and outer protector members have at bottom walls thereof bottom gas holes.

The oxygen sensor of the present invention has excellent durability capable of effectively preventing contamination with lead or the like for a detection electrode even in low temperature exhaust gases, and having stable response over a long period of time. The contamination preventive layer provided in the sensor device comprises composite powders having coarse powders covered therearound with fine powders, and hollows not filled with fine powders are scattered in gaps among the composite powders. Both the coarse and fine powders comprise ceramic powders. Further, it is particularly preferred that the ceramic powders are powders of a titania powder having a peak at 1 &mgr;m or less and a composite ceramic powder containing alumina such as spinel having a peak at 10 &mgr;m or more. The contamination preventive layer can be formed by coating a slurry containing ceramic powders of different specific surface areas, an organic binder and a solvent such as methanol on the surface of the electrode protection layer followed by drying.

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Konan, Japan

Takayoshi Atsumi