Ngk Spark Plug Company, Limited

Makoto Kume

Yuichi Yamada

Shingo Ito

Takehiro Oba

Daisuke Tahira

Noboru Matsui

Nobuhiro Inoue

Tomohisa Fujita

Hiroshi Inagaki

Satoshi Teramoto

Takeshi Kawai

Keiichi Noda

Shinya Miyamoto

Tomohiro Nakamura

Takuya Saito

Hironari Furuta

Shinichiro Iwama

Kumiko Yoshikawa

Takeshi Nanbu

Suguru Kyoumoto

Takahiro Akiyama

A gas sensor is provided with a metal shell protecting member formed of a material superior in heat resistance to a metal shell, whereby a high-temperature measurement target (exhaust gas) is prevented from being in direct contact with a region, of a protector internal region of the metal shell, on the front side relative to a protector opposing surface. That is, in the gas sensor, it is possible to suppress corrosion, due to high temperature, of a region, of the protector internal region of the metal shell, on the front side relative to the protector opposing surface (an inner surface and a front end surface of a protector fixing portion), while the metal shell is formed of a material (SUS430) that can be subjected to working (crimping or the like) accompanied with deformation. Therefore, heat resistance of the entire sensor can be improved.

Sensor

A gas sensor includes a sensor element having electrode take-out portions; a tubular separator having a flange portion, surrounding the electrode take-out portions, and spaced from a metallic shell; a tubular outer sleeve covering the separator, connected to the metallic shell, and having an inward convex portion that contacts the rearward-facing surface of the separator and restricts rearward movement of the separator; a seal member disposed on the rear of the separator and accommodated in a rear portion of the outer sleeve such that it is spaced from the separator; and an annular retainer fixed to the outer sleeve and in contact with a contact surface which forms at least a portion of the forward-facing surface of the flange portion. The separator has a rotation restriction surface for restricting its rotation in the circumferential direction, and the retainer has an engagement surface which contacts the rotation restriction surface.

Gas sensor

Disclosed is a gas sensor having a metal shell, a holder placed in the metal shell and a sensor element inserted through an axial insertion hole of the holder. The holder has a recessed portion recessed toward the rear from a front end face of the holder. The sensor element has, at a front end part thereof, a detection portion covered with a porous protection layer such that a rear end of the porous protection layer is situated within the recessed portion of the holder and is located at the rear side with respect to the front end face of the holder while maintaining a space between an inner circumferential surface of the recessed portion and an outer circumferential surface of the porous protection layer.

A gas sensor () has a platelike detection element () extending in an axial direction and a ceramic member () having an element insertion hole () into which the detection element () is inserted. When the ceramic member () is viewed from the axial direction, the element insertion hole () has a main insertion hole () having a substantially quadrate shape surrounded by four sides, and relief holes (), (), () and (), each of which is surrounded by an outline connecting ends of two adjacent sides of the four sides of the main insertion hole () and located radially outward of the main insertion hole () so as to communicate with the main insertion hole

In a gas sensor (), a base end portion () of a second outer wall () of an outer protector () is connected airtightly to a forward end portion () of a first inner wall () of an inner protector (), and relations of A&#x2266;B&#x3c;C&#x3c;D and (0.6&#xd7;B)&#x2266;A are satisfied, wherein A represents the total opening area of a second outer hole () of the outer protector (), B represents the total opening area of a second inner hole () of the inner protector (), C represents the total opening area of a first inner hole (), and D represents the total opening area of a first outer hole.

A protector () is inserted into a metallic shell () such that at least a portion of each gas introduction hole () is located on the base end side with respect to the forward end () of the metallic shell. The metallic shell has a gas introduction space Sdefined by a forward-end-side inner surface () of the metallic shell and an outer surface () of the protector and which guides a gas-to-be-detected (exhaust gas G) from a region on the forward end side of the metallic shell into the gas introduction holes of the protector. The base end of the forward end portion () of the detection element () is located on the base end side with respect to the forward end () of each gas introduction hole, and the forward end of the forward end portion is located on the forward end side with respect to the base end () of each gas introduction hole.

A sensor includes a detection element; a plurality of terminal members, each of the terminal members including an elongated frame body portion extending along the axial direction, an element contact portion in elastic contact with an electrode terminal, and a folded portion connecting the frame body portion and the element contact portion; and a separator. The element contact portion of each of the terminal members has a turning portion which turns inward with respect to the width direction between the folded portion and a contact portion in contact with an electrode terminal. In those two of the terminal members which are adjacent to each other along the width direction, the distance along the width direction between the contact portions is smaller than the distance along the width direction between the frame body portions.

Sensor and terminal member

Disclosed is a gas sensor including a metal shell, a ceramic holder placed in an axial inner hole of the metal shell and a sensor element inserted through an insertion hole of the ceramic holder. The ceramic holder has a recessed hole recessed toward the rear from a front-facing surface of the ceramic holder. The sensor element has, at a front end part thereof, a detection portion covered with a porous protection layer such that a rear end part of the protection layer is accommodated in the recessed hole with a space left therebetween. Further, the ceramic holder has a front circumferential edge defined between an inner circumferential surface of the recessed hole and the front-facing surface of the ceramic holder such that the whole of the front circumferential edge is located radially inside of a radially innermost position of the axial hole.

A gas sensor including coating layers () and () of fluorine or a fluorine compound formed on the surface of a separator (), including a front separator () and a rear separator (), disposed inside a sheath (). The coating layers () and () have water impermeability and water repellency. Even in the case where moisture contained in the atmosphere within a sheath () forms dew on the surface of the separator (), the coating layers () and () prevent soaking of moisture into the separator (), to thereby secure the insulation property of the separator (). Also, the coating layers () and () having water repellency prevent a water droplet from spreading on the surface of the separator () with resultant formation of a film of water, to thereby prevent flow of leakage current via a film of water.

In a gas sensor (), a base end portion () of a second outer wall () of an outer protector () is airtightly connected to a forward end portion () of a first inner wall () of an inner protector (). The outer protector () has a taper wall () which is located on the axially forward end side of the second outer wall (). The taper wall () has the shape of a tapered tube whose diameter decreases toward the axially forward end side, and has a second outer hole (), which is a forward end opening. The entire taper wall () is disposed on the axially forward end side in relation to the inner bottom wall () of the inner protector ().

A sensor () includes a sensor element (), a tubular metallic shell (), and a tubular mounting member () rotatable relative to the metallic shell. The metallic shell has a body () and a flange () provided forward of the mounting member and projecting radially outward beyond the radially inner surface of the mounting member. Further, the radially outer surface of the body and the rearward-oriented surface of the flange are connected by a slant surface (). The mounting member is such that a forward-oriented surface () and a radially inner surface () meet at a corner (). When a threaded portion () of the mounting member is threadingly engaged with a mounting hole () of a mount body (), a forward-oriented surface () of the flange comes into contact with a mounting surface () of the mount body, and the corner comes into contact with the slant surface.

Gas sensor and gas sensor installation structure

A sensor including: a sensor element; terminal metal fittings; a terminal surrounding member; and lead wires. The terminal surrounding member is divided into a front side surrounding member and a rear side surrounding member, and a rear end face of the front side surrounding member abuts a front end face of the rear side surrounding member. The sensor includes a fitting structure including a recess portion formed on one of the rear and front end faces and a protruding portion formed on the other, such that one of the front side surrounding member and the rear side surrounding member is prevented from rotating relative to the other about an axis of the sensor, and is prevented from deviating in a direction perpendicular to the axis of the sensor relative to the other.

There is provided a gas sensor, which includes a sensor element extending axially of the gas sensor and having a gas sensing portion at a front end thereof and an electrode portion at a rear end thereof, a cylindrical metal shell retaining therein the sensor element with the gas sensing portion and the electrode portion protruding from front and rear ends of the metal shell, respectively, and having a flange portion and a rear end portion located on a rear side of the flange portion, a cylindrical protection cover having a front end fitted onto the rear end portion of the metal shell so as to cover the electrode portion and a weld joint through which the entire circumference of the front end of the protection cover is joined through the metal shell. The weld joint extends from an end face of the protection cover to the metal shell.

Gas sensor and manufacturing method thereof

A sensor including a sensor element including a plurality of electrode terminals, terminal metal fittings, a terminal surrounding member, and lead wires connected to respective terminal metal fittings. The terminal surrounding member is divided into a front side surrounding member and a rear side surrounding member in the front-rear direction, and a rear end face of the front side surrounding member abuts a front end face of the rear side surrounding member. At least one of the terminal metal fittings includes a protruding piece portion protruding in a lateral direction and held between the rear end face of the front side surrounding member and the front end face of the rear side surrounding member.

A sensor including: a detecting element () as defined herein; a plurality of metallic terminal members () as defined herein; and an insulating separator () as defined herein, wherein the insulating separator includes: an outer separator () which surrounds the electrode terminal portions of the detecting element and the metallic terminal members; and an inner separator () at least a portion of which is disposed radially inwardly of the outer separator and which has partition walls () for positioning the plurality of metallic terminal members and insulating the plurality of metallic terminal members from one another.

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Inuyama, Japan

Makoto Kume