JP2012233785A

JP2012233785A - Gas sensor

Info

Publication number: JP2012233785A
Application number: JP2011102647A
Authority: JP
Inventors: Hidekazu Kato; 秀和加藤; Yasushi Matsuo; 康司松尾; Kengo Shimizu; 健吾清水
Original assignee: NGK Spark Plug Co Ltd
Current assignee: Niterra Co Ltd
Priority date: 2011-05-02
Filing date: 2011-05-02
Publication date: 2012-11-29
Anticipated expiration: 2031-05-02
Also published as: JP5399440B2

Abstract

PROBLEM TO BE SOLVED: To provide a gas sensor in which an outside terminal can stably hold a gas sensor element and reliability of electric connection between the outside terminal and the gas sensor element is hardly lowered even if the outside terminal moves relative to the gas sensor element.SOLUTION: A gas sensor 100 comprises: a gas sensor element 3 that includes a bottomed cylindrical element body 3s whose tip is exposed to gas to be measured and outside electrodes 3c provided on an outside surface from the tip of the element body to a rear end thereof; and an outside terminal 91 that includes a cylindrical part 93 for enclosing the rear end of the gas sensor element from a radial direction and electrically connected to the outside electrodes. The cylindrical part has a notch 93a for notching the cylindrical part and capable of elastically deforming in the radial direction, and a protrusion 93b arranged at the notch and protruding inward in the radial direction. The cylindrical part holds the rear end of the gas sensor element, and the protrusion is in contact with the outside electrodes while the notch elastically deforms in the radial direction.

Description

本発明は、被検出ガスの濃度を検出するガスセンサ素子を備えたガスセンサに関する。 The present invention relates to a gas sensor including a gas sensor element that detects the concentration of a gas to be detected.

自動車等の排気ガス中の特定ガス（酸素やＮＯ_ｘ）の濃度を検出するガスセンサとして、固体電解質を用いたガスセンサ素子を有するものが知られている。このようなガスセンサとして、図７に示すように、軸線Ｏ方向に延びる筒状であって、固体電解質からなる素子本体３ｓの先端部から後端部の外表面に亘って、検出部３ｃｓ、リード部３ｃＬ、接続部３ｃｐとからなる外側電極３ｃを形成したガスセンサ素子３を備えた構成が知られている。又、この外側電極３ｃから出力を取り出すため、ガスセンサには、ガスセンサ素子３の後端部を径方向から包囲する筒状部９３０を備えた外側端子９１０が設けられている。筒状部９３０は軸線方向ＯにスリットＭを有する金属筒であり、ガスセンサ素子３により径方向に広げられてガスセンサ素子３の後端部に外嵌される。
一方、外側端子９１０には、筒状部９３０の後端側に板状基部９４０が形成され、さらに、板状基部９４０の後端にリード線（図示せず）の芯線に加締め接続される接続端部９５０が配置されている。そして、板状基部９４０をセパレータの挿通孔（図示せず）に挿入保持している。 As a gas sensor for detecting the concentration of a specific gas (oxygen or NO _x ) in exhaust gas of an automobile or the like, one having a gas sensor element using a solid electrolyte is known. As such a gas sensor, as shown in FIG. 7, it is a cylindrical shape extending in the direction of the axis O, and extends from the front end portion of the element main body 3s made of a solid electrolyte to the outer surface of the rear end portion, the detection portion 3cs, the lead A configuration including a gas sensor element 3 in which an outer electrode 3c including a portion 3cL and a connection portion 3cp is formed is known. In order to extract the output from the outer electrode 3c, the gas sensor is provided with an outer terminal 910 having a cylindrical portion 930 that surrounds the rear end portion of the gas sensor element 3 in the radial direction. The cylindrical portion 930 is a metal cylinder having a slit M in the axial direction O, is expanded in the radial direction by the gas sensor element 3, and is fitted on the rear end portion of the gas sensor element 3.
On the other hand, the outer terminal 910 is formed with a plate-like base portion 940 on the rear end side of the tubular portion 930, and is further crimped and connected to a core wire of a lead wire (not shown) at the rear end of the plate-like base portion 940. A connecting end 950 is disposed. The plate-like base portion 940 is inserted and held in an insertion hole (not shown) of the separator.

又、筒状部９３０の一部に、径方向内側に折り曲げた複数の切り起こし部９３０ｂ、９３４を設けている。このうち２個の切り起こし部９３０ｂを外側電極３ｃの接続部３ｃｐに当接させることで、筒状部９３０と接続部３ｃｐとの電気的接続を行うと共に、切り起こし部９３０ｂ、９３４を用いてガスセンサ素子３を保持している技術が開発されている（特許文献１）。 In addition, a plurality of cut-and-raised portions 930 b and 934 that are bent inward in the radial direction are provided in a part of the cylindrical portion 930. Of these, the two cut-and-raised portions 930b are brought into contact with the connection portion 3cp of the outer electrode 3c, whereby the cylindrical portion 930 and the connection portion 3cp are electrically connected, and the cut-and-raised portions 930b and 934 are used. A technique for holding the gas sensor element 3 has been developed (Patent Document 1).

特開２０１０−１８１３４７号公報(図３、図４、図５)JP 2010-181347 A (FIGS. 3, 4, and 5) 特開２０１０−２７１２８４号公報（図１、図４）JP 2010-271284 A (FIGS. 1 and 4)

しかしながら、特許文献１記載の技術の場合、筒状部９３０をガスセンサ素子３の後端部より径大として両者を非接触とし、切り起こし９３０ｂ、９３４のみでガスセンサ素子３を保持している。この場合、切り起こし９３０ｂ、９３４はガスセンサ素子３を点で支持するだけであるので、安定した保持の点で改善の余地がある。 However, in the case of the technique described in Patent Document 1, the cylindrical portion 930 is larger in diameter than the rear end portion of the gas sensor element 3 so that they are not in contact with each other, and the gas sensor element 3 is held only by the cut and raised 930 b and 934. In this case, since the cut-and-raised 930b and 934 only support the gas sensor element 3 with a point, there is room for improvement in terms of stable holding.

これに対し、特許文献２のように筒状部にてガスセンサ素子の後端部を保持するとともに、この筒状部を外側電極の接続部に当接させることで、筒状部と接続部との電気的接続を行う技術も開発されている。しかしながら、筒状部がガスセンサ素子に対し相対的に動くと、筒状部の一部がガスセンサ素子から離間することで、筒状部と接続部とが離間する可能性が高くなり、電気的接続の信頼性が低下するおそれがある。 On the other hand, while holding the rear end part of the gas sensor element in the cylindrical part as in Patent Document 2, the cylindrical part and the connecting part are brought into contact with the connecting part of the outer electrode. A technology for making electrical connections has also been developed. However, if the cylindrical portion moves relative to the gas sensor element, the cylindrical portion and the connecting portion are more likely to be separated due to a part of the cylindrical portion being separated from the gas sensor element. There is a risk that the reliability of the system will be reduced.

従って、本発明は、外側端子をガスセンサ素子に安定して保持できると共に、外側端子がガスセンサ素子に対し相対的に動いても、両者の電気的接続の信頼性が低下され難いガスセンサの提供を目的とする。 Accordingly, an object of the present invention is to provide a gas sensor that can stably hold the outer terminal on the gas sensor element and that is less likely to reduce the reliability of electrical connection between the outer terminal and the gas sensor element even when the outer terminal moves relative to the gas sensor element. And

上記課題を解決するため、本発明のガスセンサは、軸線方向に延び、先端部が被測定ガスに晒される有底筒状の素子本体と、該素子本体の先端部から後端部の外表面に設けられた外側電極とを有するガスセンサ素子と、前記ガスセンサ素子の後端部を径方向から包囲して前記外側電極に電気的に接続される筒状部を有する外側端子と、を備えたガスセンサであって、前記筒状部は、該筒状部を切り欠いて径方向に弾性変形可能な切り欠き部と、前記切り欠き部に配置されて径方向内側に突出する凸部とを有し、前記筒状部が、前記ガスセンサ素子の後端部を保持すると共に、前記切り欠き部が径方向に弾性変形しつつ、前記凸部が前記外側電極に当接する。 In order to solve the above problems, a gas sensor according to the present invention includes a bottomed cylindrical element body that extends in the axial direction and whose tip is exposed to the gas to be measured, and the outer surface of the element body from the tip to the rear end A gas sensor comprising: a gas sensor element having an outer electrode provided; and an outer terminal having a cylindrical portion that surrounds a rear end portion of the gas sensor element from a radial direction and is electrically connected to the outer electrode. The cylindrical portion has a notch portion that is cut out of the cylindrical portion and elastically deformable in the radial direction, and a convex portion that is disposed in the notch portion and protrudes radially inward. The tubular portion holds the rear end portion of the gas sensor element, and the convex portion comes into contact with the outer electrode while the notch portion is elastically deformed in the radial direction.

このガスセンサによれば、ガスセンサ素子の後端部と外側端子との機械的な保持は、切り欠き部を除く筒状部で積極的に行われる一方で、外側端子と外側電極との電気的な接続は、径方向に弾性変形する切り欠き部内に配置された凸部で行われる。このため、筒状部全体でガスセンサ素子の後端部に線又は面で接触するのでガスセンサ素子を安定して保持できると共に、筒状部がガスセンサ素子に対し相対的に動いても、筒状部と独立に動く切り欠き部がその動きを吸収するので、切り欠き部内に配置された凸部と外側電極とを確実に当接させることができ、外側端子と外側電極との電気的接続の信頼性が低下され難い。
又、外側電極との電気的接点が必ず凸部の位置となり、軸線方向での電気的接点の位置が特定されるので、外側電極の形成位置をこの位置近傍までに限定することができる。これにより、外側電極の長さを短くすることができ、外側電極に用いる材料（貴金属等）の使用量が低減し、コストダウンが図られる。 According to this gas sensor, the mechanical holding of the rear end portion of the gas sensor element and the outer terminal is positively performed in the cylindrical portion excluding the notch portion, while the electrical connection between the outer terminal and the outer electrode is performed. The connection is made with a convex portion arranged in a notch that elastically deforms in the radial direction. For this reason, since the entire cylindrical portion contacts the rear end portion of the gas sensor element with a line or a surface, the gas sensor element can be stably held, and the cylindrical portion can be moved even if the cylindrical portion moves relative to the gas sensor element. The notch that moves independently from each other absorbs the movement, so that the convex portion arranged in the notch and the outer electrode can be reliably brought into contact with each other, and the electrical connection between the outer terminal and the outer electrode is reliable. It is hard to be lowered.
In addition, since the electrical contact with the outer electrode always becomes the position of the convex portion, and the position of the electrical contact in the axial direction is specified, the formation position of the outer electrode can be limited to the vicinity of this position. Thereby, the length of an outer electrode can be shortened, the usage-amount of the material (noble metal etc.) used for an outer electrode reduces, and cost reduction is aimed at.

さらに、本発明のガスセンサにおいて、前記外側電極は、前記素子本体の先端側の全周に亘って設けられる検出部と、前記素子本体の後端側の周方向の一部に設けられて前記検出部と前記外側端子と電気的に接続する接続部とを有し、前記切り欠き部が周方向に複数設けられ、少なくとも１つの前記切り欠き部が有する前記凸部に前記接続部が当接しているとよい。
このガスセンサによれば、周方向に複数の切り欠き部を設けることで、接続部を周方向の一部に設けたとしても、少なくとも１つの切り欠き部内に配置された凸部が接続部に確実に当接させることができ、外側端子と外側電極との電気的接続の信頼性が低下され難い。そのうえ、外側電極を素子本体の後端部の全周に設ける必要がなくなり、接続部に用いる材料（貴金属等）の使用量が低減し、コストダウンが図られる。 Furthermore, in the gas sensor according to the present invention, the outer electrode is provided on a detection portion provided over the entire circumference on the front end side of the element body and on a part of the circumferential direction on the rear end side of the element body. And a plurality of cutout portions provided in the circumferential direction, and the connection portion is in contact with the convex portion of at least one cutout portion. It is good to be.
According to this gas sensor, by providing a plurality of cutout portions in the circumferential direction, even if the connection portion is provided in a part of the circumferential direction, the convex portion arranged in at least one cutout portion is surely provided in the connection portion. The reliability of the electrical connection between the outer terminal and the outer electrode is unlikely to be lowered. In addition, it is not necessary to provide the outer electrode on the entire periphery of the rear end portion of the element body, so that the amount of the material (noble metal or the like) used for the connection portion is reduced and the cost is reduced.

さらに、本発明のガスセンサにおいて、前記筒状部を前記軸線方向に見て１２０度の間隔で３つの領域に分割したとき、前記切り欠き部がそれぞれの領域に少なくとも１つ配置されているとよい。
このガスセンサによれば、凸部のいずれかが外側電極に接触する可能性が高くなり、外側端子と外側電極との確実な導通が図られるので好ましい。 Furthermore, in the gas sensor of the present invention, when the cylindrical portion is divided into three regions at intervals of 120 degrees when viewed in the axial direction, at least one notch portion may be disposed in each region. .
According to this gas sensor, there is a high possibility that any one of the convex portions comes into contact with the outer electrode, and it is preferable because reliable conduction between the outer terminal and the outer electrode is achieved.

さらに、本発明のガスセンサにおいて、前記切り欠き部が周方向に等間隔で配置されていると、外側電極に凸部が片当たりせずに均等に接触し易くなり、外側端子と外側電極との確実な導通が図られるので好ましい。 Furthermore, in the gas sensor according to the present invention, when the notches are arranged at equal intervals in the circumferential direction, the convex portions do not come into contact with the outer electrode, and the outer terminals and the outer electrodes are easily contacted. Since reliable conduction is achieved, it is preferable.

さらに、本発明のガスセンサにおいて、前記筒状部が、自身の先端縁から後端縁にかけて前記軸線方向に延びるスリットが形成され、断面Ｃ型形状に形成されていると、筒状部をガスセンサ素子に外嵌して拡開した際にバネ力によって筒状部が縮まり、ガスセンサ素子に押圧されるので、ガスセンサ素子をより一層安定して保持できる。なお、筒状部の自由状態（ガスセンサ素子の後端部を保持する前での状態）の内径は、ガスセンサ素子の外径よりも径小であることは言うまでもない。 Furthermore, in the gas sensor according to the present invention, when the cylindrical portion is formed with a slit extending in the axial direction from the front end edge to the rear end edge of the cylindrical portion and formed in a C-shaped cross section, the cylindrical portion is When the tube is externally fitted and expanded, the cylindrical portion is contracted by the spring force and pressed by the gas sensor element, so that the gas sensor element can be held more stably. In addition, it cannot be overemphasized that the internal diameter of the cylindrical part in the free state (state before hold | maintaining the rear-end part of a gas sensor element) is smaller than the outer diameter of a gas sensor element.

この発明によれば、外側端子をガスセンサ素子に安定して保持できると共に、外側端子がガスセンサ素子に対し相対的に動いても、両者の電気的接続の信頼性が低下され難い。 According to the present invention, the outer terminal can be stably held on the gas sensor element, and even if the outer terminal moves relative to the gas sensor element, the reliability of the electrical connection between the two is hardly lowered.

本発明の実施形態に係るガスセンサを軸線方向に沿う面で切断した断面図である。It is sectional drawing which cut | disconnected the gas sensor which concerns on embodiment of this invention by the surface which follows an axial direction. ガスセンサ素子及び外側端子の構造を示す斜視図である。It is a perspective view which shows the structure of a gas sensor element and an outer side terminal. 外側端子の筒状部をガスセンサ素子の後端側の外周面に外嵌した状態を示す斜視図である。It is a perspective view which shows the state which fitted the cylindrical part of the outer side terminal to the outer peripheral surface of the rear end side of a gas sensor element. 図３を軸線方向に垂直な平面で切断した断面図である。It is sectional drawing which cut | disconnected FIG. 3 by the plane perpendicular | vertical to an axial direction. 図４においてガスセンサ素子が軸線方向に垂直な方向（図５の矢印Ａ）に動いたときの断面図である。FIG. 6 is a cross-sectional view when the gas sensor element moves in a direction perpendicular to the axial direction (arrow A in FIG. 5) in FIG. 4. セパレータアセンブリとセンサ素子アセンブリとを組み付けてガスセンサを製造する態様を示す図である。It is a figure which shows the aspect which assembles | assembles a separator assembly and a sensor element assembly, and manufactures a gas sensor. 従来の外側端子の構造を示す斜視図である。It is a perspective view which shows the structure of the conventional outer side terminal.

以下、本発明の実施形態について説明する。
図１は、本発明の実施形態に係るガスセンサ１００を軸線Ｏ方向（先端から後端に沿う方向）に沿う面で切断した断面構造を示す。この実施形態において、ガスセンサ１００は自動車の排気管内に挿入されて先端（図１のプロテクタ７側）が排気ガス中に曝され、排気ガス中の酸素濃度を検出する酸素センサになっている。
なお、図１の下側（プロテクタ７側）をガスセンサ１００の先端側とし、図１の上側をガスセンサ１００の後端側とする。 Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a cross-sectional structure in which a gas sensor 100 according to an embodiment of the present invention is cut along a plane along an axis O direction (a direction along the rear end from the front end). In this embodiment, the gas sensor 100 is an oxygen sensor that is inserted into an exhaust pipe of an automobile and the tip (the protector 7 side in FIG. 1) is exposed to the exhaust gas to detect the oxygen concentration in the exhaust gas.
The lower side (the protector 7 side) in FIG. 1 is the front end side of the gas sensor 100, and the upper side in FIG.

ガスセンサ１００は、ガスセンサ素子３がハウジング（主体金具）２０内に組み付けられている。このうち、ガスセンサ素子３は、酸素イオン伝導性の固体電解質体に一対の電極を積層した酸素濃淡電池を構成し、酸素量に応じた検出値を出力する公知の酸素ガスセンサ素子である。詳細には、ガスセンサ素子３は、先端に向かってテーパ状に縮径する有底筒状の固体電解質体（特許請求の範囲の「素子本体」に相当、図２参照）と、固体電解質体の内周面と外周面にそれぞれ形成された内側電極３ｂ及び外側電極３ｃとからなる。そして、ガスセンサ素子３の内部空間を基準ガス雰囲気とし、ガスセンサ素子３の外面に被検出ガスを接触させてガスの検知を行うようになっている。
ガスセンサ素子３の中央付近には、径方向外側に突出する鍔部３ａが設けられている。一方、ハウジング２０の先端寄りの内周面には内側に縮径する段部２０ｅが設けられ、鍔部３ａと段部２０ｅの間にパッキン１２が配置されている。そして、ガスセンサ素子３をハウジング２０の内側に挿通し、鍔部３ａをパッキン１２に当てることにより、間接的に段部２０ｅに後端側からガスセンサ素子３の鍔部３ａが当接し、ガスセンサ素子３がハウジング２０内に組み付けられている。 In the gas sensor 100, the gas sensor element 3 is assembled in a housing (metal shell) 20. Among these, the gas sensor element 3 is a known oxygen gas sensor element that constitutes an oxygen concentration cell in which a pair of electrodes are stacked on an oxygen ion conductive solid electrolyte body and outputs a detection value corresponding to the amount of oxygen. Specifically, the gas sensor element 3 includes a bottomed cylindrical solid electrolyte body (corresponding to the “element body” in the claims, see FIG. 2) that tapers toward the tip, and a solid electrolyte body. It consists of an inner electrode 3b and an outer electrode 3c respectively formed on the inner peripheral surface and the outer peripheral surface. Then, the internal space of the gas sensor element 3 is set as a reference gas atmosphere, and the gas to be detected is brought into contact with the outer surface of the gas sensor element 3 to detect the gas.
Near the center of the gas sensor element 3, a flange 3 a that protrudes radially outward is provided. On the other hand, on the inner peripheral surface near the tip of the housing 20, a step portion 20e having a diameter reduced inward is provided, and the packing 12 is disposed between the flange portion 3a and the step portion 20e. Then, the gas sensor element 3 is inserted into the inside of the housing 20, and the flange 3 a is applied to the packing 12, so that the flange 3 a of the gas sensor element 3 is indirectly brought into contact with the stepped portion 20 e from the rear end side. Is assembled in the housing 20.

さらに、鍔部３ａの後端側におけるガスセンサ素子３とハウジング２０との径方向の隙間に、筒状のシール材（滑石粉末）６が充填され、さらにシール材６の後端側に筒状の絶縁部材（セラミックスリーブ）３１が配置されている。そして、絶縁部材３１の後端側に金属リング（ステンレス製の平ワッシャ）３０を配し、ハウジング２０の後端部を内側に屈曲して加締め部２０ａを形成することにより、絶縁部材３１が先端側に押し付けられてシール材６を押し潰し、絶縁部材３１及びシール材６が加締め固定されるとともに、ガスセンサ素子３とハウジング２０の隙間がシールされている。 Further, a cylindrical seal material (talc powder) 6 is filled in a radial gap between the gas sensor element 3 and the housing 20 on the rear end side of the flange 3 a, and a cylindrical shape is further formed on the rear end side of the seal material 6. An insulating member (ceramic sleeve) 31 is disposed. Then, a metal ring (stainless flat washer) 30 is disposed on the rear end side of the insulating member 31 and the rear end portion of the housing 20 is bent inward to form the crimped portion 20a. The insulating material 31 and the sealing material 6 are crimped and fixed by being pressed against the distal end side, and the gap between the gas sensor element 3 and the housing 20 is sealed.

さらに、ハウジング２０の後端には、ガスセンサ素子３の後端部を覆うため、金属製筒状の外筒４０が接合されている。この外筒４０は、例えば、ＳＵＳ４３０、ＳＵＳ３０４、ＳＵＳ３０４Ｌ、ＳＵＳ３１０Ｓ、ＳＵＳ３１６、ＳＵＳ３１６Ｌ等のステンレス鋼を用いることができる。外筒４０は、ハウジング２０に接続する先端部４０ａと先端部４０ａよりも縮径された後端部４０ｂとを有し、先端部４０ａと後端部４０ｂとの間には、段部４３が設けられている。 Further, a metal cylindrical outer cylinder 40 is joined to the rear end of the housing 20 in order to cover the rear end portion of the gas sensor element 3. For the outer cylinder 40, for example, stainless steel such as SUS430, SUS304, SUS304L, SUS310S, SUS316, SUS316L, or the like can be used. The outer cylinder 40 has a front end portion 40a connected to the housing 20 and a rear end portion 40b having a diameter smaller than that of the front end portion 40a. A stepped portion 43 is provided between the front end portion 40a and the rear end portion 40b. Is provided.

外筒４０の先端部４０ａの内側面には、絶縁性の筒状のセパレータ１１１が配置されている。さらに、セパレータ１１１の２個の挿通孔１１５、１１６にそれぞれ内側端子７１、外側端子９１の板状基部７４、９４が挿通されて固定されている。この各板状基部７４、９４の後端にはそれぞれ接続端部７５、９５が形成され、接続端部７５、９５にそれぞれリード線１４１、１４１が加締め接続されている。 An insulating cylindrical separator 111 is disposed on the inner side surface of the distal end portion 40 a of the outer cylinder 40. Further, the plate-like base portions 74 and 94 of the inner terminal 71 and the outer terminal 91 are inserted and fixed in the two insertion holes 115 and 116 of the separator 111, respectively. Connection end portions 75 and 95 are formed at the rear ends of the plate-like base portions 74 and 94, respectively, and lead wires 141 and 141 are caulked and connected to the connection end portions 75 and 95, respectively.

また、セパレータ１１１は、セパレータ１１１の後端面を段部４３に当接させつつ、セパレータ１１１の先端面をセパレータ１１１よりも先端側に配置した保持金具４５に当接させることで、外筒４０内に保持される。この保持金具４５は、セパレータ１１１よりも先端側に配置され、外筒４０の先端部４０ａが加締められることで外筒４０内に固定されている。 In addition, the separator 111 abuts the inner end of the outer cylinder 40 by bringing the front end surface of the separator 111 into contact with the holding metal fitting 45 disposed on the front end side of the separator 111 while bringing the rear end surface of the separator 111 into contact with the stepped portion 43. Retained. The holding metal fitting 45 is disposed on the front end side of the separator 111, and is fixed in the outer cylinder 40 by crimping the front end portion 40 a of the outer cylinder 40.

内側端子７１には、板状基部７４に接続し、ガスセンサ素子３の筒孔３ｄ内に内嵌された挿入部７３が設けられている。この挿入部７３は、筒形状を有し、ガスセンサ素子３の内側に設けられた内側電極３ｂと電気的に接続される。また、外側端子９１には、板状基部９４に接続詞、ガスセンサ素子３の外側に外嵌された筒状部９３が設けられている。この筒状部９３は、筒形状を有し、ガスセンサ素子３の外側に設けられた外側電極３ｃと電気的に接続される。なお、外側端子９１の詳細については後述する。 The inner terminal 71 is provided with an insertion portion 73 that is connected to the plate-like base portion 74 and is fitted into the cylindrical hole 3 d of the gas sensor element 3. The insertion portion 73 has a cylindrical shape and is electrically connected to an inner electrode 3 b provided on the inner side of the gas sensor element 3. In addition, the outer terminal 91 is provided with a cylindrical portion 93 that is externally fitted to the outer side of the gas sensor element 3 with a connector on the plate-like base 94. The tubular portion 93 has a tubular shape and is electrically connected to the outer electrode 3 c provided outside the gas sensor element 3. Details of the outer terminal 91 will be described later.

外筒４０の後端部４０ｂの内側には筒状のグロメット１３１が内挿されて加締め固定されている。このグロメット１３１には、２個の挿通孔からそれぞれリード線１４１、１４１が外部に引き出されている。又、グロメット１３１の後端側がフランジ状に拡径しており、この拡径部分を外筒４０の後端に載置することにより、グロメット１３１の位置決めがされる。グロメット１３１としては、例えばシリコンゴムやフッ素ゴム等からなるゴムキャップを用いることができる。 A cylindrical grommet 131 is inserted inside the rear end portion 40b of the outer cylinder 40 and fixed by crimping. In the grommet 131, lead wires 141 and 141 are drawn out from the two insertion holes, respectively. Further, the rear end side of the grommet 131 is enlarged in a flange shape, and the grommet 131 is positioned by placing this enlarged diameter portion on the rear end of the outer cylinder 40. As the grommet 131, for example, a rubber cap made of silicon rubber, fluorine rubber, or the like can be used.

さらに、外筒４０の後端部４０ｂの側面のうち、グロメット１３１よりも先端側の位置には、周方向に等間隔で４個（図１では３個のみ図示）の第１通気孔４１が開口している。そして、外筒４０の後端部４０ｂの径方向外側には、第１通気孔４１を塞ぐように、環状の通気性のフィルタ５０が被せられ、さらに、フィルタ５０を径方向外側から金属製筒状の保護外筒６０が囲んでいる。この保護外筒６０は、例えば、ＳＵＳ４３０、ＳＵＳ３０４、ＳＵＳ３０４Ｌ、ＳＵＳ３１０Ｓ、ＳＵＳ３１６、ＳＵＳ３１６Ｌ等のステンレス鋼を用いることができる。保護外筒６０の側面には、周方向に等間隔で４個（図１では２個のみ図示）の第２通気孔６１が開口し、フィルタ５０を介して外筒４０内部へ外気を導入可能になっている。なお、第２通気孔６１及び第１通気孔４１の先後で外筒４０及び保護外筒６０を加締めることで、外筒４０と保護外筒６０の間にフィルタ５０を保持している。フィルタ５０は、例えばフッ素系樹脂等の樹脂の多孔質構造体からなり、撥水性を有しているため外部の水を通さずにセンサ素子３の内部空間に基準ガス（大気）を導入する。 Further, on the side surface of the rear end portion 40b of the outer cylinder 40, four first vent holes 41 (only three are shown in FIG. 1) are arranged at equal intervals in the circumferential direction at a position closer to the front end side than the grommet 131. It is open. An annular breathable filter 50 is covered on the radially outer side of the rear end portion 40b of the outer cylinder 40 so as to close the first ventilation hole 41. Further, the filter 50 is made of a metal cylinder from the radially outer side. A cylindrical protective outer cylinder 60 surrounds. For example, stainless steel such as SUS430, SUS304, SUS304L, SUS310S, SUS316, and SUS316L can be used for the protective outer cylinder 60. Four second vent holes 61 (only two are shown in FIG. 1) are opened at equal intervals in the circumferential direction on the side surface of the protective outer cylinder 60, and the outside air can be introduced into the outer cylinder 40 through the filter 50. It has become. The filter 50 is held between the outer cylinder 40 and the protective outer cylinder 60 by crimping the outer cylinder 40 and the protective outer cylinder 60 before the second ventilation hole 61 and the first ventilation hole 41. The filter 50 is made of, for example, a porous structure of resin such as fluorine resin, and has water repellency, and therefore introduces a reference gas (atmosphere) into the internal space of the sensor element 3 without passing external water.

保護外筒６０は、後端部がグロメット１３１の後端面上に設けられるように径方向内側に折り曲げられてなり、後端部の中央に開口６３が形成され、開口からリード線１４１、１４１が外部に引き出されている。さらに、保護外筒６０の後端側には、外筒４０の後端部４０ｂに設けられた加締め部に加締め固定されている。つまり、グロメット１３１は、保護外筒６０及び外筒４０の両者を同時に加締めることで、外筒４０内に配置されている。 The protective outer cylinder 60 is bent radially inward so that the rear end portion is provided on the rear end surface of the grommet 131, and an opening 63 is formed at the center of the rear end portion, and lead wires 141 and 141 are formed from the opening. Has been pulled out. Further, on the rear end side of the protective outer cylinder 60, it is fixed by caulking to a caulking portion provided at the rear end portion 40b of the outer cylinder 40. That is, the grommet 131 is disposed in the outer cylinder 40 by simultaneously caulking both the protective outer cylinder 60 and the outer cylinder 40.

一方、ハウジング２０の先端部２０ｆには金属製（ステンレスなど）で筒状のプロテクタ７が固定され、ハウジング２０から突出するガスセンサ素子３の先端がプロテクタ７で覆われている。このプロテクタ７は、排気ガスをプロテクタ７の内部に取り込むための複数の孔部を有している。 On the other hand, a cylindrical protector 7 made of metal (such as stainless steel) is fixed to the distal end portion 20 f of the housing 20, and the distal end of the gas sensor element 3 protruding from the housing 20 is covered with the protector 7. The protector 7 has a plurality of holes for taking the exhaust gas into the protector 7.

なお、ハウジング２０の中央付近には、径方向外側に突出し六角レンチ等を係合するための多角形の鍔部２０ｃが設けられ、鍔部２０ｃと先端部２０ｆとの間のハウジング２０外側面には雄ねじ部２０ｄが形成されている。又、鍔部２０ｃの先端面と雄ねじ部２０ｄの後端との間の段部には、排気管に取付けた際のガス抜けを防止するガスケット（図示せず）が嵌挿されている。
そして、ハウジング２０の雄ねじ部２０ｄを排気管等のネジ孔に取付けることで、ガスセンサ素子３の先端を排気管内に露出させて被検出ガス（排気ガス）を検知している。 In the vicinity of the center of the housing 20, a polygonal flange portion 20c that protrudes radially outward and engages with a hexagon wrench or the like is provided, and is formed on the outer surface of the housing 20 between the flange portion 20c and the tip portion 20f. Has a male screw portion 20d. Further, a gasket (not shown) for preventing gas escape when attached to the exhaust pipe is fitted into a step portion between the front end surface of the flange portion 20c and the rear end of the male screw portion 20d.
Then, by attaching the male screw portion 20d of the housing 20 to a screw hole such as an exhaust pipe, the tip of the gas sensor element 3 is exposed in the exhaust pipe to detect the detected gas (exhaust gas).

次に、図２、図３を参照し、本発明の特徴部分である外側端子９１の構成を説明する。外側端子９１は、先端から後端に細長く延び、所定の形状に打ち抜かれた金属薄板（耐食耐熱超合金板）を曲げ加工して一体に形成されている。外側端子９１の後端側には板状基部９４が形成され、板状基部９４の後端側にはリード線１４１の芯線に加締め接続される接続端部９５が配置されている。板状基部９４の先端側には筒状部９３が接続されている。さらに板状基部９４の軸線方向中央側には、他の部位より広幅の広幅部９４ｗが形成され、広幅部９４ｗの中央部は後端側が固定されたコ字状に打ち抜かれ、広幅部９４ｗの背面側（前面と反対側の面）に切起こされた切り起こし部９４Ｙが設けられている。
そして、板状基部９４をセパレータ１１１の挿通孔１１６（図６参照）に挿入した際、板状基部９４が挿通孔１１６内に位置決めされる。又、上記した切起こし部９４Ｙが挿通孔１１６の外端壁に当接し、そのバネ力によって板状基部９４を挿通孔１１６内に保持している。 Next, the configuration of the outer terminal 91, which is a characteristic part of the present invention, will be described with reference to FIGS. The outer terminal 91 extends from the front end to the rear end and is integrally formed by bending a thin metal plate (corrosion-resistant heat-resistant superalloy plate) punched into a predetermined shape. A plate-like base portion 94 is formed on the rear end side of the outer terminal 91, and a connection end portion 95 that is caulked and connected to the core wire of the lead wire 141 is disposed on the rear end side of the plate-like base portion 94. A cylindrical portion 93 is connected to the distal end side of the plate-like base portion 94. Further, a wide portion 94w that is wider than other portions is formed on the center side in the axial direction of the plate-like base portion 94, and the central portion of the wide portion 94w is punched into a U-shape with the rear end side fixed, and the wide portion 94w A cut-and-raised portion 94Y cut and raised on the back side (the surface opposite to the front side) is provided.
When the plate-like base portion 94 is inserted into the insertion hole 116 (see FIG. 6) of the separator 111, the plate-like base portion 94 is positioned in the insertion hole 116. Further, the cut and raised portion 94Y contacts the outer end wall of the insertion hole 116, and the plate-like base portion 94 is held in the insertion hole 116 by the spring force.

一方、筒状部９３は後端と先端とを結ぶ軸線を中心とする筒状をなし、かつ板状基部９４と反対側に母線に沿ったスリットＭを有している。そして、筒状部９３の内径は、ガスセンサ素子３の後端部の外径より小さく、筒状部９３をガスセンサ素子３に外嵌して拡開した際にバネ力によって筒状部９３が縮まり、ガスセンサ素子３の外側電極３ｃに押圧されるようになっている。
さらに、筒状部９３の軸線Ｏ方向の中央近傍には、自身をコ字状に切り欠いた切り欠き部９３ａが、周方向に等間隔で５個（図２では３個のみ表示）設けられている。そして、各切り欠き部９３ａの中央には、径方向内側に突出する正方形の凸部（ダボ）９３ｂが設けられている。ここで、切り欠き部９３ａの軸線Ｏ方向に平行な一辺が固定端となっており、切り欠き部９３ａはこの固定端を支点として径方向に弾性的に変形（縮径及び拡径）可能である。凸部９３ｂは、外側端子９１と外側電極３ｃ（後述する接続部３ｃｐ）とを電気的に接続するものであり、この実施形態では、凸部９３ｂはプレス加工によって切り欠き部９３ａから突出している。
なお、切り欠き部９３ａの径方向に力が加えられていない自由状態では、切り欠き部９３ａは筒状部９３の板面と面一になっているが、切り欠き部９３ａに力が加えられたときに筒状部９３の板面に対して縮径及び拡径することで、後述するように、外側端子９１がガスセンサ素子３に対し相対的に動いても、切り欠き部９３ａがその動きを吸収するので電気的接続の信頼性が低下され難い。又、凸部９３ｂと外側電極３ｃとの電気的接続の信頼性をより確実にするため、凸部９３ｂの突出高さを調整する（例えば、高くする）ことが好ましい。 On the other hand, the cylindrical portion 93 has a cylindrical shape centering on an axis connecting the rear end and the distal end, and has a slit M along the generatrix on the opposite side to the plate-shaped base portion 94. The inner diameter of the cylindrical portion 93 is smaller than the outer diameter of the rear end portion of the gas sensor element 3, and when the cylindrical portion 93 is fitted on the gas sensor element 3 and expanded, the cylindrical portion 93 is contracted by the spring force. The gas sensor element 3 is pressed against the outer electrode 3c.
Further, in the vicinity of the center of the cylindrical portion 93 in the direction of the axis O, five cutout portions 93a are formed at equal intervals in the circumferential direction (only three are shown in FIG. 2). ing. And in the center of each notch part 93a, the square convex part (dowel) 93b which protrudes to radial inside is provided. Here, one side parallel to the direction of the axis O of the notch portion 93a is a fixed end, and the notch portion 93a can be elastically deformed (reduced diameter and expanded diameter) in the radial direction with the fixed end as a fulcrum. is there. The convex portion 93b electrically connects the outer terminal 91 and the outer electrode 3c (a connecting portion 3cp described later). In this embodiment, the convex portion 93b protrudes from the notch portion 93a by press working. .
In a free state in which no force is applied in the radial direction of the cutout portion 93a, the cutout portion 93a is flush with the plate surface of the cylindrical portion 93, but a force is applied to the cutout portion 93a. When the outer terminal 91 moves relative to the gas sensor element 3 as will be described later, the notch portion 93a moves as described below. Therefore, it is difficult to reduce the reliability of electrical connection. Further, in order to make the electrical connection between the convex portion 93b and the outer electrode 3c more reliable, it is preferable to adjust (for example, increase) the protruding height of the convex portion 93b.

ここで、図２に示すように、外側電極（検知電極）３ｃはガスセンサ素子３の素子本体３ｓ外面の先端側に形成され、さらに外側電極３ｃは、素子本体３ｓの先端側の全周に亘って設けられる検出部３ｃｓと、検出部３ｃｓから後端に延びる線状のリード部３ｃＬと、素子本体３ｓの後端側に周方向の一部に延びるように設けられてリード部３ｃＬ（検出部３ｃｓ）と接続する接続部３ｃｐとを有している。そして、筒状部９３の凸部９３ｂは、接続部３ｃｐに接続される。
なお、接続部３ｃｐは周方向にリード部３ｃＬより広幅（幅Ｓ_１）で形成され、接続部３ｃとリード部３ｃＬとがＴ字状をなしている。又、内側電極３ｂ（図１参照）は、素子本体３ｓの先端部から後端部の内孔３ｄの表面に設けられている。 Here, as shown in FIG. 2, the outer electrode (detection electrode) 3c is formed on the distal end side of the outer surface of the element body 3s of the gas sensor element 3, and the outer electrode 3c extends over the entire circumference on the distal end side of the element body 3s. A detection part 3cs provided in a linear manner, a linear lead part 3cL extending from the detection part 3cs to the rear end, and a lead part 3cL (detection part) provided so as to extend partly in the circumferential direction on the rear end side of the element body 3s. 3cs) and a connecting portion 3cp. And the convex part 93b of the cylindrical part 93 is connected to the connection part 3cp.
The connecting portion 3cp is formed with a width (width S ₁ ) wider than the lead portion 3cL in the circumferential direction, and the connecting portion 3c and the lead portion 3cL form a T shape. The inner electrode 3b (see FIG. 1) is provided on the surface of the inner hole 3d from the front end portion to the rear end portion of the element body 3s.

そして、図３に示すように、外側端子９１の筒状部９３をガスセンサ素子３の後端側の外周面に外嵌し、ガスセンサ素子３外面の外側電極３ｃ（接続部３ｃｐ）と、筒状部９３（凸部９３ｂ）とを当接させる。また、ガスセンサ素子３に外嵌した際に筒状部９３は拡開し、バネ力によって筒状部９３が縮まるので、ガスセンサ素子３が筒状部９３により強固に保持される。 Then, as shown in FIG. 3, the cylindrical portion 93 of the outer terminal 91 is fitted on the outer peripheral surface on the rear end side of the gas sensor element 3, and the outer electrode 3 c (connection portion 3 cp) on the outer surface of the gas sensor element 3 is connected to the cylindrical shape. The part 93 (convex part 93b) is brought into contact. Further, when the gas sensor element 3 is externally fitted, the cylindrical portion 93 is expanded, and the cylindrical portion 93 is contracted by the spring force, so that the gas sensor element 3 is firmly held by the cylindrical portion 93.

図４は、図３を軸線方向Ｏに垂直な平面で切断した断面図である。筒状部９３は弾性力によって縮まるので真円とはならず、周方向の幾つかの位置で筒状部９３とガスセンサ素子３外面とが接触（片当たり）し、ガスセンサ素子３は筒状部９３に挟持されている。ここで、筒状部９３はスリットＭを有するＣ型形状に形成されているため、筒状部９３はスリットＭ近傍、及びスリットＭと対向する位置（板状基部９４と接続される位置）でガスセンサ素子３と接触するが、図４の側方でガスセンサ素子３と隙間Ｇを形成している。
この場合、筒状部９３がガスセンサ素子３と接触(近接)する位置では、切り欠き部９３ａが径方向外側に大きく逃げることで、切り欠き部９３ａ内の凸部９３ｂが接続部３ｃｐに当接する。また、筒状部９３がガスセンサ素子３と離間して隙間Ｇを有する側方位置では、切り欠き部９３ａの径方向外側に小さく逃げることで、凸部９３ｂが接続部３ｃｐに当接する。 4 is a cross-sectional view of FIG. 3 cut along a plane perpendicular to the axial direction O. FIG. Since the cylindrical portion 93 is contracted by the elastic force, it does not become a perfect circle, but the cylindrical portion 93 and the outer surface of the gas sensor element 3 come into contact with each other at several positions in the circumferential direction. 93. Here, since the cylindrical portion 93 is formed in a C-shape having the slit M, the cylindrical portion 93 is in the vicinity of the slit M and at a position facing the slit M (a position connected to the plate-shaped base portion 94). Although contacting the gas sensor element 3, a gap G is formed with the gas sensor element 3 on the side of FIG.
In this case, at the position where the cylindrical portion 93 is in contact with (adjacent to) the gas sensor element 3, the notch portion 93a largely escapes outward in the radial direction, so that the convex portion 93b in the notch portion 93a comes into contact with the connection portion 3cp. . Further, at the side position where the cylindrical portion 93 is spaced apart from the gas sensor element 3 and has the gap G, the convex portion 93b comes into contact with the connecting portion 3cp by escaping to the outside in the radial direction of the notch portion 93a.

図５は、図４においてガスセンサ素子３が軸線方向Ｏに垂直な方向（図５の矢印Ａ）に動いたときの断面図である。筒状部９３内でガスセンサ素子３が左側（図５の矢印Ａ）に動くと、筒状部９３の左側がガスセンサ素子３とより多く接触する一方で、筒状部９３の右側の隙間Ｇが大きくなる。
この場合、筒状部９３の左側では、切り欠き部９３ａが径方向外側に大きく逃げることで、切り欠き部９３ａ内の凸部９３ｂと接続部３ｃｐとの当接が維持される。一方、筒状部９３の右側では、切り欠き部９３ａが径方向内側へ戻る（縮径する）ことで、凸部９３ｂと接続部３ｃｐとの当接が維持される。そして、このように筒状部９３とガスセンサ素子３外面との距離に応じて切り欠き部９３ａが径方向に弾性変形するので、切り欠き部９３ａ内の凸部９３ｂが接続部３ｃｐに常に接続部３ｃｐに押圧され、ガスセンサ素子３と筒状部９３との確実な電気的接続が維持される。 5 is a cross-sectional view when the gas sensor element 3 in FIG. 4 moves in a direction perpendicular to the axial direction O (arrow A in FIG. 5). When the gas sensor element 3 moves to the left side (arrow A in FIG. 5) in the cylindrical portion 93, the left side of the cylindrical portion 93 is more in contact with the gas sensor element 3, while the gap G on the right side of the cylindrical portion 93 is growing.
In this case, on the left side of the tubular portion 93, the notch portion 93a largely escapes radially outward, so that the contact between the convex portion 93b in the notch portion 93a and the connection portion 3cp is maintained. On the other hand, on the right side of the cylindrical portion 93, the notch portion 93a returns to the inner side in the radial direction (reduces its diameter), so that the contact between the convex portion 93b and the connection portion 3cp is maintained. Since the cutout portion 93a is elastically deformed in the radial direction according to the distance between the cylindrical portion 93 and the outer surface of the gas sensor element 3 in this way, the convex portion 93b in the cutout portion 93a is always connected to the connection portion 3cp. Pressed by 3 cp, a reliable electrical connection between the gas sensor element 3 and the cylindrical portion 93 is maintained.

このように、ガスセンサ素子３の後端部と外側端子９１との機械的な保持は、切り欠き部９３ａを除く筒状部９３で積極的に行われる一方で、外側端子９１と外側電極３ｃとの電気的な接続は、径方向に弾性変形する切り欠き部９３ａ内に配置された凸部９３ｂで行われる。
このため、筒状部９３全体でガスセンサ素子３の後端部に線又は面で接触するのでガスセンサ素子３を安定して保持できると共に、筒状部９３がガスセンサ素子３に対し相対的に動いても、筒状部９３と独立に動く切り欠き部９３ａがその動きを吸収するので、切り欠き部９３ａ内に配置された凸部９３ｂと外側電極３ｃとを確実に当接させることができ、外側端子９１と外側電極３ｃとの電気的接続の信頼性が低下され難い。
又、筒状部９３のガスセンサ素子３への嵌合深さは、外筒４０（図７参照）に固定される際の筒状部９３の軸線Ｏ方向の位置に応じて予め決められており、さらに本発明においては外側電極３ｃとの電気的接点が必ず凸部９３ｂの位置となる。このため、軸線方向Ｏでの電気的接点の位置が特定されるので、図２に示すように接続部３ｃｐの軸線方向Ｏの長さＳ_２をこの接点近傍に限定することができ、接続部３ｃｐに用いる材料（貴金属等）の使用量が低減してコストダウンが図られる。 As described above, the mechanical holding of the rear end portion of the gas sensor element 3 and the outer terminal 91 is positively performed by the cylindrical portion 93 excluding the notch portion 93a, while the outer terminal 91, the outer electrode 3c, The electrical connection is performed by a convex portion 93b disposed in a notch portion 93a that is elastically deformed in the radial direction.
For this reason, since the whole cylindrical part 93 contacts the rear end part of the gas sensor element 3 with a line or a surface, the gas sensor element 3 can be stably held, and the cylindrical part 93 moves relative to the gas sensor element 3. In addition, since the cutout portion 93a that moves independently of the cylindrical portion 93 absorbs the movement, the convex portion 93b disposed in the cutout portion 93a and the outer electrode 3c can be reliably brought into contact with each other. The reliability of the electrical connection between the terminal 91 and the outer electrode 3c is hardly lowered.
The fitting depth of the cylindrical portion 93 to the gas sensor element 3 is determined in advance according to the position of the cylindrical portion 93 in the axis O direction when being fixed to the outer cylinder 40 (see FIG. 7). Further, in the present invention, the electrical contact with the outer electrode 3c is always the position of the convex portion 93b. Therefore, the position of the electrical contacts in the axial direction O is identified, can be limited to the contact near the length S ₂ of the axial O of the connection portion 3cp as shown in FIG. 2, the connecting portion The amount of materials (noble metals, etc.) used for 3cp is reduced, and the cost is reduced.

さらに、周方向に複数の切り欠き部９３ａを設けることで、接続部３ｃｐを周方向の一部に設けたとしても、少なくとも１つの切り欠き部９３ａ内に配置された凸部９３ｂが接続部３ｃｐに確実に当接させることができ、外側端子９１と外側電極３ｃとの電気的接続の信頼性が低下され難い。そのうえ、外側電極３ｃを素子本体３ｓの後端部の全周に設ける必要がなくなり、接続部３ｃｐに用いる材料（貴金属等）の使用量が低減し、コストダウンが図られる。 Further, by providing a plurality of cutout portions 93a in the circumferential direction, even if the connection portion 3cp is provided in a part of the circumferential direction, the convex portion 93b disposed in at least one cutout portion 93a is connected to the connection portion 3cp. The reliability of the electrical connection between the outer terminal 91 and the outer electrode 3c is difficult to be lowered. In addition, it is not necessary to provide the outer electrode 3c on the entire circumference of the rear end portion of the element body 3s, so that the amount of a material (noble metal or the like) used for the connection portion 3cp is reduced and the cost can be reduced.

特に、図２の実施形態では、接続部３ｃｐは周方向に幅Ｓ_１で形成され、一方で外側端子９１において、隣接する切り欠き部９３ａの周方向の間隔（＝凸部９３ｂの間隔）Ｓ_３で形成されている。このとき、Ｓ_３＜Ｓ_１の関係を満たすことで、接続部３ｃｐに対する外側端子９１の周方向の向きによらず、少なくとも１個以上の凸部９３ｂが必ず接続部３ｃｐに接触することになる。よって、外側電極３ｃと外側端子９１との位置合わせを行うことなく接点を確保することができ、組み付けが容易になる。なお、切り欠き部９３ａ（＝凸部９３ｂ）の周方向の間隔が等間隔でなくともよく、隣接する切り欠き部９３ａの間隔のうち、最大のものがＳ_３＜Ｓ_１の関係を満たせば、上記効果を奏することができる。 In particular, in the embodiment of FIG. 2, the connecting portion 3cp is formed with a width S ₁ in the circumferential direction, while the outside terminal 91, (distance = protrusions 93 b) circumferential spacing between adjacent notches 93a S ₃ is formed. At this time, by satisfying the relationship of S ₃ <S ₁ , at least one or more protrusions 93b always come into contact with the connection portion 3cp regardless of the circumferential direction of the outer terminal 91 with respect to the connection portion 3cp. . Therefore, a contact can be secured without aligning the outer electrode 3c and the outer terminal 91, and assembly is facilitated. Note that the intervals in the circumferential direction of the notches 93a (= projections 93b) may not be equal, and the maximum one of the intervals between the adjacent notches 93a satisfies the relationship of S ₃ <S _1. The above effects can be achieved.

又、筒状部９３を軸線方向Ｏに見て１２０度の間隔で３つの領域に分割したとき、切り欠き部９３ａがそれぞれの領域に少なくとも１つ配置されていれば、凸部９３ｂのいずれかが外側電極３ｃに接触する割合が高くなり、外側端子９１と外側電極３ｃとの確実な導通が図られるので好ましい。
又、切り欠き部９３ａが周方向に等間隔で配置されていると、外側電極３ｃに凸部９３ｂが片当たりせずに均等に接触し易くなり、外側端子９１と外側電極３ｃとの確実な導通が図られるので好ましい。 Further, when the cylindrical portion 93 is divided into three regions at intervals of 120 degrees when viewed in the axial direction O, if at least one notch portion 93a is arranged in each region, any one of the convex portions 93b This is preferable because the ratio of contact with the outer electrode 3c is increased and reliable conduction between the outer terminal 91 and the outer electrode 3c is achieved.
Further, when the notches 93a are arranged at equal intervals in the circumferential direction, the convex portions 93b do not come into contact with the outer electrode 3c evenly, and the outer terminals 91 and the outer electrodes 3c are reliably contacted. Since conduction is achieved, it is preferable.

次に、図６を参照し、このガスセンサ１００の製造方法について説明する。まず、ガスセンサ素子３を主体金具２０の内側に保持してセンサ素子アセンブリＢを組み付ける。具体的には、ガスセンサ素子３を主体金具２０内に配置されたパッキン１２上に配置する。その後、主体金具２０とガスセンサ素子３との間隙にシール材６を充填し、絶縁部材３１、金属リング３０を順にシール材６上に配置し、主体金具２の後端側を加締めてセンサ素子アセンブリＢを組み付ける。一方で、外筒４０内に、内側端子７１及び外側端子９１を組み付けたセパレータ１１１をグロメット１３１と共に配置し、セパレータアセンブリＡを組み付ける。具体的には、リード線１４１に接続された内側端子７１及び外側端子９１をセパレータ１１１の挿通孔１１５、１１６内に挿入し、その後、セパレータ１１１を外筒４０の段部４３に当接する。その後、セパレータ１１１と外筒４との間隙に保持金具４５を挿入して、外筒４０の先端部４０ａを加締め保持金具４５を固定する。さらに、グロメット１３１を外筒４０の後端から挿入すると共に、外筒４０の後端部４０ｂにフィルタ５０、保護外筒６０をそれぞれ配置し、フィルタ５０、グロメット１３１をそれぞれ加締め固定することで、セパレータアセンブリＡを組み付ける。そして、セパレータアセンブリＡをセンサセンサ素子アセンブリＢとの軸線を合わせ、セパレータアセンブリＡをセンサ素子アセンブリＢの後端に被せると、内側端子７１の筒状の挿入部７３がガスセンサ素子３の後端の筒孔３ｄ内に内嵌され、ガスセンサ素子３内面の内側電極（基準電極）３ｂと電気的に接続される。又、外側端子９１の筒状部９３はガスセンサ素子３の後端側の外周面に外嵌され、ガスセンサ素子３外面の外側電極（検知電極）３ｃと電気的に接続される。そして、外筒４０の先端部をハウジング２０に外嵌し、外筒４０の先端部の外周面をレーザ溶接等によって主体金具２０の後端部に接続し、ガスセンサ１００を製造する。 Next, a manufacturing method of the gas sensor 100 will be described with reference to FIG. First, the sensor element assembly B is assembled while holding the gas sensor element 3 inside the metal shell 20. Specifically, the gas sensor element 3 is disposed on the packing 12 disposed in the metal shell 20. Thereafter, the seal material 6 is filled in the gap between the metal shell 20 and the gas sensor element 3, the insulating member 31 and the metal ring 30 are sequentially disposed on the seal material 6, and the rear end side of the metal shell 2 is crimped to form the sensor element. Assemble assembly B. On the other hand, the separator 111 assembled with the inner terminal 71 and the outer terminal 91 is arranged together with the grommet 131 in the outer cylinder 40, and the separator assembly A is assembled. Specifically, the inner terminal 71 and the outer terminal 91 connected to the lead wire 141 are inserted into the insertion holes 115 and 116 of the separator 111, and then the separator 111 is brought into contact with the step portion 43 of the outer cylinder 40. Thereafter, the holding metal fitting 45 is inserted into the gap between the separator 111 and the outer cylinder 4, and the distal end portion 40 a of the outer cylinder 40 is fixed by crimping. Further, the grommet 131 is inserted from the rear end of the outer cylinder 40, and the filter 50 and the protective outer cylinder 60 are respectively arranged on the rear end portion 40b of the outer cylinder 40, and the filter 50 and the grommet 131 are respectively fixed by crimping. Then, the separator assembly A is assembled. When the separator assembly A is aligned with the axis of the sensor sensor element assembly B and the separator assembly A is put on the rear end of the sensor element assembly B, the cylindrical insertion portion 73 of the inner terminal 71 is connected to the rear end of the gas sensor element 3. It is fitted in the cylindrical hole 3d and is electrically connected to the inner electrode (reference electrode) 3b on the inner surface of the gas sensor element 3. The cylindrical portion 93 of the outer terminal 91 is fitted on the outer peripheral surface of the rear end side of the gas sensor element 3 and is electrically connected to the outer electrode (detection electrode) 3c on the outer surface of the gas sensor element 3. And the front-end | tip part of the outer cylinder 40 is fitted by the housing 20, and the outer peripheral surface of the front-end | tip part of the outer cylinder 40 is connected to the rear-end part of the metal shell 20 by laser welding etc., and the gas sensor 100 is manufactured.

本発明は上記実施形態に限定されず、本発明の思想と範囲に含まれる様々な変形及び均等物に及ぶことはいうまでもない。
切り欠き部は１個以上形成されれば個数は限定されず、切り欠き部の形状も限定されない。例えば、切り欠き部をＵ字状に切り欠いてもよい。切り欠き部の固定端の位置についても、図２のような側方でなく、先端側又は後端側であってもよい。
１つの切り欠き部内部に配置される凸部の個数も１個以上であればよく、凸部の形状も限定されない。但し、１つの切り欠き部内部に１個の凸部を配置した方が外側電極との接点の位置が明瞭になると共に、外側端子がガスセンサ素子に対し相対的に動いたときに切り欠き部にその動きを伝え易いので好ましい。又、同じ理由から、切り欠き部の重心となる位置に凸部を配置してもよい。
又、本発明はヒータレスセンサに限らず、ヒータを有するガスセンサにも適用可能である。
さらに、ガスセンサ素子としては、筒状の素子であれば、上記した酸素センサ素子（λセンサ素子）の他、アンモニアセンサ素子、ＨＣセンサ素子、Ｈ_２センサ素子等に用いることができる。 It goes without saying that the present invention is not limited to the above-described embodiment, but extends to various modifications and equivalents included in the spirit and scope of the present invention.
The number of cutouts is not limited as long as one or more cutouts are formed, and the shape of the cutouts is not limited. For example, the cutout portion may be cut out in a U shape. The position of the fixed end of the notch may also be the front end side or the rear end side instead of the side as shown in FIG.
The number of convex portions arranged inside one notch may be one or more, and the shape of the convex portions is not limited. However, if one protrusion is arranged inside one notch, the position of the contact point with the outer electrode becomes clear and the notch becomes a notch when the outer terminal moves relative to the gas sensor element. It is preferable because the movement is easy to convey. Further, for the same reason, the convex portion may be arranged at a position that becomes the center of gravity of the notch portion.
Further, the present invention is not limited to a heaterless sensor, but can be applied to a gas sensor having a heater.
Furthermore, as a gas sensor element, as long as it is a cylindrical element, it can be used for an ammonia sensor element, an HC sensor element, an H ₂ sensor element, etc., in addition to the oxygen sensor element (λ sensor element) described above.

３ガスセンサ素子
３ｃ外側電極
３ｃｓ検出部
３ｃｐ接続部
３ｓ素子本体
９１外側端子
９３筒状部
９３ａ切り欠き部
９３ｂ凸部
１００ガスセンサ
Ｏ軸線方向
Ｍスリット DESCRIPTION OF SYMBOLS 3 Gas sensor element 3c Outer electrode 3cs Detection part 3cp Connection part 3s Element main body 91 Outer terminal 93 Cylindrical part 93a Notch part 93b Protrusion part 100 Gas sensor O Axis direction M Slit

Claims

軸線方向に延び、先端部が被測定ガスに晒される有底筒状の素子本体と、該素子本体の先端部から後端部の外表面に設けられた外側電極とを有するガスセンサ素子と、
前記ガスセンサ素子の後端部を径方向から包囲して前記外側電極に電気的に接続される筒状部を有する外側端子と、を備えたガスセンサであって、
前記筒状部は、該筒状部を切り欠いて径方向に弾性変形可能な切り欠き部と、前記切り欠き部に配置されて径方向内側に突出する凸部とを有し、
前記筒状部が、前記ガスセンサ素子の後端部を保持すると共に、前記切り欠き部が径方向に弾性変形しつつ、前記凸部が前記外側電極に当接するガスセンサ。 A gas sensor element having a bottomed cylindrical element body that extends in the axial direction and whose tip is exposed to the gas to be measured; and an outer electrode provided on the outer surface of the rear end from the tip of the element body;
An outer terminal having a cylindrical portion surrounding the rear end portion of the gas sensor element from the radial direction and electrically connected to the outer electrode;
The cylindrical part has a notch part that is notched in the cylindrical part and can be elastically deformed in the radial direction, and a convex part that is arranged in the notch part and protrudes radially inward.
A gas sensor in which the cylindrical portion holds a rear end portion of the gas sensor element, and the protruding portion is in contact with the outer electrode while the cutout portion is elastically deformed in a radial direction.

前記外側電極は、前記素子本体の先端側の全周に亘って設けられる検出部と、前記素子本体の後端側の周方向の一部に設けられて前記検出部と前記外側端子とを電気的に接続する接続部とを有し、
前記切り欠き部が周方向に複数設けられ、少なくとも１つの前記切り欠き部が有する前記凸部に前記接続部が当接している請求項１に記載のガスセンサ。 The outer electrode is provided on a part of the circumferential direction on the rear end side of the element body, and is provided between the detection part and the outer terminal. And a connection part for connecting
2. The gas sensor according to claim 1, wherein a plurality of the cutout portions are provided in a circumferential direction, and the connection portion is in contact with the convex portion of at least one cutout portion.

前記筒状部を前記軸線方向に見て１２０度の間隔で３つの領域に分割したとき、前記切り欠き部がそれぞれの領域に少なくとも１つ配置されている請求項１又は２に記載のガスセンサ。 3. The gas sensor according to claim 1, wherein when the cylindrical portion is divided into three regions at intervals of 120 degrees when viewed in the axial direction, at least one notch portion is disposed in each region.

前記切り欠き部が周方向に等間隔で配置されている請求項３に記載のガスセンサ。 The gas sensor according to claim 3, wherein the notches are arranged at equal intervals in the circumferential direction.

前記筒状部は、自身の先端縁から後端縁にかけて前記軸線方向に延びるスリットが形成され、断面Ｃ型形状に形成されている請求項１〜４のいずれかに記載のガスセンサ。 The gas sensor according to any one of claims 1 to 4, wherein the cylindrical portion is formed with a slit extending in the axial direction from a leading edge to a trailing edge of the cylindrical portion, and is formed in a C-shaped cross section.