JP2008304449A - Gas sensor and manufacturing method thereof - Google Patents

Gas sensor and manufacturing method thereof Download PDF

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JP2008304449A
JP2008304449A JP2008029567A JP2008029567A JP2008304449A JP 2008304449 A JP2008304449 A JP 2008304449A JP 2008029567 A JP2008029567 A JP 2008029567A JP 2008029567 A JP2008029567 A JP 2008029567A JP 2008304449 A JP2008304449 A JP 2008304449A
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outer cylinder
metal shell
rear end
tip
gas sensor
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JP5129599B2 (en
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Makoto Kume
誠 久米
Yuichi Yamada
裕一 山田
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Niterra Co Ltd
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NGK Spark Plug Co Ltd
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Priority to JP2008029567A priority Critical patent/JP5129599B2/en
Priority to US12/099,516 priority patent/US8257577B2/en
Priority to EP08007054.3A priority patent/EP1990635B1/en
Priority to CN 200810081854 priority patent/CN101303326B/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas sensor preventing corrosion in a weld of a main fitting and an outer cylinder, and also to provide a manufacturing method thereof. <P>SOLUTION: In a gas sensor the top end 66 of an outer cylinder 65 is engaged in the rear-end engagement portion 57 of a main fitting 50 and the portion engaged by them is laser-welded over the entire periphery in the radial direction about the abutment position (the vicinity of the border of them shown by an arrow B). A welded portion 99 melted by laser irradiation is formed astride the top end 66 of the outer cylinder 65 and of the cylinder 571 of the main fitting 50. This welded portion 99 seals the gap between the end surface 69 of the outer cylinder 65, which becomes an entrance portion to the gap between the inner peripheral surface 68 of the outer cylinder and the outer peripheral surface 573 of the rear end engagement portion 57 of the main fitting 50, and the rear end facing surface 574 of the engagement portion 57. This prevents water drops from infiltrating into the gap. Corrosion is thereby prevented which is likely to occur when water drops are in contact with the welded portion 99 over a long period. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、排気ガス中の被検出ガスの濃度を検出するための検出素子を備えたガスセンサおよびその製造方法に関するものである。   The present invention relates to a gas sensor including a detection element for detecting the concentration of a gas to be detected in exhaust gas and a method for manufacturing the same.

従来、自動車などの排気ガス中の被検出ガス、例えばＮＯｘ（窒素酸化物）や酸素などの濃度を検出するための検出部を有する検出素子を備えたガスセンサが知られている。このような検出素子は自動車の排気管に取り付けるための主体金具に保持されて、自身の先端側に設けられた検出部が排気管内に露出されるようにして使用される。また、検出素子の後端側には検出部からの出力信号を取り出すための電極が設けられており、その電極部分を含む検出素子の後端側は主体金具の後端側から露出されている。そして電極には外部回路との接続を行うためのリード線が電気的に接続され、この接続部分を含む検出素子の後端部分を保護するため、主体金具の後端側には筒状の外筒が接合されている。   2. Description of the Related Art Conventionally, a gas sensor including a detection element having a detection unit for detecting the concentration of a gas to be detected in exhaust gas of an automobile or the like, for example, NOx (nitrogen oxide) or oxygen is known. Such a detection element is used by being held by a metal shell to be attached to an exhaust pipe of an automobile so that a detection portion provided on the front end side of the detection element is exposed in the exhaust pipe. In addition, an electrode for taking out an output signal from the detection unit is provided on the rear end side of the detection element, and the rear end side of the detection element including the electrode portion is exposed from the rear end side of the metal shell. . A lead wire for connecting to an external circuit is electrically connected to the electrode, and in order to protect the rear end portion of the detection element including this connection portion, a cylindrical outer part is provided on the rear end side of the metal shell. The cylinder is joined.

このようなガスセンサの製造過程において、主体金具と外筒との接合は、通常、レーザ溶接により行われる。具体的には、外筒の先端を主体金具の後端側に形成した係合部に重ね合わせ、加締めによる仮止め後、あるいはそのままの状態で、外筒の外周側から全周にわたってレーザを照射して、外筒と主体金具とを接合している（例えば、特許文献１および特許文献２参照。）。
特開２００４−３５４２７４号公報 特開２００１−１４７２１３号公報 In the manufacturing process of such a gas sensor, the metal shell and the outer cylinder are usually joined by laser welding. Specifically, the front end of the outer cylinder is overlaid on the engagement portion formed on the rear end side of the metal shell, and after temporary fixing by caulking or in the state as it is, the laser is applied from the outer peripheral side of the outer cylinder to the entire circumference. Irradiation is performed to join the outer cylinder and the metal shell (for example, see Patent Document 1 and Patent Document 2).
JP 2004-354274 A JP 2001-147213 A

しかしながら、特許文献１や特許文献２では、レーザ接合により形成される溶接部が外筒の先端よりも後端側に位置する形態であり、外筒の先端から溶接部にかけての部位は、外筒の内周面と主体金具の外周面とが密接状態となっているものの接合されているわけではないため、僅かながら間隙を有する場合がある。ガスセンサが使用中に被水すると毛細管現象によりその間隙に水滴等が浸入する場合があり、このような間隙に入り込んだ水滴等は比較的揮発しにくいため、その間隙内にて溶接部が長期間水滴等に接触した状態となってしまう虞がある。特に主体金具において、レーザ溶接によって一度溶融した部分の界面は比較的腐食を生じやすいため、溶接部が長期間水滴等に接触した状態となると、溶接部と非溶接部との界面において腐食を生ずる虞があった。   However, in Patent Document 1 and Patent Document 2, the welded portion formed by laser bonding is located on the rear end side of the outer tube tip, and the portion from the outer tube tip to the welded portion is the outer tube. Although the inner peripheral surface of the metal plate and the outer peripheral surface of the metal shell are in close contact with each other, they are not joined, so there may be a slight gap. If the gas sensor is exposed to water during use, water droplets or the like may enter the gap due to capillarity, and the water droplets entering the gap are relatively difficult to volatilize. There is a risk of contact with water droplets. Especially in metal shells, the interface of the part once melted by laser welding is relatively susceptible to corrosion. Therefore, when the welded part is in contact with water droplets or the like for a long time, corrosion occurs at the interface between the welded part and the non-welded part. There was a fear.

本発明は、上記問題点を解決するためになされたものであり、主体金具と外筒との溶接部において腐食を生じにくいようにすることができるガスセンサおよびその製造方法を提供することを目的とする。   The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a gas sensor that can prevent corrosion from occurring in a welded portion between a metal shell and an outer cylinder, and a method for manufacturing the same. To do.

上記目的を達成するために、請求項１に係る発明のガスセンサは、軸線方向に延びると共に、自身の先端側に被検出ガスを検出するための検出部を有する検出素子と、前記検出部を自身の先端から突出させつつ、前記検出素子の径方向周囲を取り囲む主体金具と、当該主体金具に固定され、前記検出素子の後端側の径方向周囲を取り囲む筒状の外筒とを有するガスセンサにおいて、前記主体金具は、径方向に拡径された鍔部と、当該鍔部の後端側に形成される後端部とを有し、前記外筒の先端が前記主体金具の前記後端部の少なくとも一部の径方向周囲を取り囲むように配置され、かつ、前記外筒の前記先端と前記主体金具とに跨って形成された溶接部が全周にわたって形成されていることを特徴とする。   In order to achieve the above object, a gas sensor according to a first aspect of the present invention includes a detection element that extends in the axial direction and has a detection unit for detecting a gas to be detected at the tip end of the gas sensor. A gas sensor having a metallic shell surrounding the radial periphery of the detection element, and a cylindrical outer cylinder fixed to the metallic shell and surrounding the radial circumference on the rear end side of the detection element The metal shell has a flange portion radially expanded in diameter and a rear end portion formed on the rear end side of the flange portion, and the front end of the outer cylinder is the rear end portion of the metal shell. The welded portion is arranged so as to surround at least a part of the circumference in the radial direction, and the welded portion is formed over the entire circumference, extending over the tip of the outer cylinder and the metal shell.

また、請求項２に係る発明のガスセンサは、請求項１に記載の発明の構成に加え、前記主体金具の前記後端部は、筒部と、当該筒部の後端側に接続し、その筒部よりも縮径する縮径部とを有し、前記外筒の前記先端は、前記縮径部の径方向周囲を取り囲むように配置され、前記溶接部は、前記外筒の前記先端と前記筒部との間に跨って形成されていることを特徴とする。   Further, in the gas sensor of the invention according to claim 2, in addition to the configuration of the invention of claim 1, the rear end portion of the metal shell is connected to a cylindrical portion and a rear end side of the cylindrical portion, A diameter-reducing portion that is smaller in diameter than the cylindrical portion, the distal end of the outer cylinder is disposed so as to surround a radial circumference of the reduced-diameter portion, and the welded portion is connected to the distal end of the outer cylinder. It is formed straddling between the cylindrical portions.

また、請求項３に係る発明のガスセンサは、請求項２に記載の発明の構成に加え、前記溶接部は、径方向における自身の厚みが、前記外筒の厚みよりも厚く形成されていることを特徴とする。   Further, in the gas sensor of the invention according to claim 3, in addition to the configuration of the invention of claim 2, the welded part is formed such that its thickness in the radial direction is larger than the thickness of the outer cylinder. It is characterized by.

また、請求項４に係る発明のガスセンサは、請求項３に記載の発明の構成に加え、前記溶接部は、径方向における自身の厚みが、前記外筒の厚みよりも２倍以上厚く形成されていることを特徴とする。   According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the invention, the welded portion is formed such that the thickness of the welded portion in the radial direction is more than twice the thickness of the outer cylinder. It is characterized by.

また、請求項５に係る発明のガスセンサは、請求項１乃至４のいずれかに記載の発明の構成に加え、前記溶接部の先端と前記鍔部の後端との距離が１ｍｍ以上であることを特徴とする。   Further, in the gas sensor of the invention according to claim 5, in addition to the configuration of the invention according to any of claims 1 to 4, the distance between the front end of the welded portion and the rear end of the flange portion is 1 mm or more. It is characterized by.

また、請求項６に係る発明のガスセンサは、請求項２乃至５のいずれかに記載の発明の構成に加え、前記外筒の前記先端と前記主体金具の前記筒部とに跨がるように、両者を外周側から加締めた加締め部が形成されていることを特徴とする。   In addition to the configuration of the invention according to any one of claims 2 to 5, the gas sensor of the invention according to claim 6 spans the tip of the outer cylinder and the cylinder portion of the metal shell. And the crimping part which crimped both from the outer peripheral side is formed, It is characterized by the above-mentioned.

また、請求項７に係る発明のガスセンサは、請求項１に記載の発明の構成に加え、前記溶接部は、前記外筒の前記先端と前記主体金具の前記鍔部との間に跨って形成されていることを特徴とする。   According to a seventh aspect of the present invention, in the gas sensor according to the seventh aspect of the invention, in addition to the configuration of the first aspect of the invention, the weld portion is formed between the tip of the outer cylinder and the flange portion of the metal shell. It is characterized by being.

また、請求項８に係る発明のガスセンサは、請求項７に記載の発明の構成に加え、前記外筒は、自身の前記先端に、径方向外側に拡径する拡径部を有し、前記溶接部は、前記拡径部と前記鍔部との間に跨って形成されていることを特徴とする。   In addition to the configuration of the invention according to claim 7, the gas sensor of the invention according to claim 8 has a diameter-expanding portion that expands radially outward at the tip of the gas sensor, The welded portion is formed between the enlarged diameter portion and the flange portion.

また、請求項９に係る発明のガスセンサは、請求項７または８に記載の発明の構成に加え、前記溶接部は、径方向内側に向かうにつれて、前記軸線方向の先端側に延びて形成されていることを特徴とする。   According to a ninth aspect of the present invention, in addition to the configuration of the seventh aspect of the present invention, the weld portion is formed to extend toward the distal end side in the axial direction as it goes radially inward. It is characterized by being.

また、請求項１０に係る発明のガスセンサは、請求項１に記載の発明の構成に加え、前記外筒の前記先端は、前記主体金具の前記鍔部とは離間しつつ前記後端部の径方向周囲を取り囲むように配置され、前記溶接部は、前記外筒の前記先端と前記主体金具の前記後端部との間に跨って形成されていることを特徴とする。   According to a tenth aspect of the present invention, in addition to the configuration of the first aspect of the invention, the front end of the outer cylinder has a diameter of the rear end portion that is separated from the flange portion of the metal shell. It arrange | positions so that the surroundings of a direction may be surrounded, The said welding part is formed ranging over between the said front-end | tip of the said outer cylinder, and the said rear-end part of the said main metal fitting, It is characterized by the above-mentioned.

また、請求項１１に係る発明のガスセンサは、請求項１０に記載の発明の構成に加え、前記溶接部は、径方向内側に向かうにつれて、前記軸線方向の後端側に延びて形成されていることを特徴とする。   In addition to the configuration of the invention according to claim 10, the gas sensor of the invention according to claim 11 is formed to extend toward the rear end side in the axial direction as it goes radially inward. It is characterized by that.

また、請求項１２に係る発明のガスセンサは、請求項７乃至１１のいずれかに記載の発明の構成に加え、前記溶接部は、径方向における自身の厚みが、前記外筒の厚みよりも厚く形成されていることを特徴とする。   Further, in the gas sensor according to a twelfth aspect of the present invention, in addition to the configuration of the invention according to any one of the seventh to eleventh aspects, the welded portion has a larger thickness in the radial direction than the thickness of the outer cylinder. It is formed.

また、請求項１３に係る発明のガスセンサは、請求項７乃至１２のいずれかに記載の発明の構成に加え、前記溶接部は、その外表面が凹んだ曲面形状に形成されることを特徴とする。   A gas sensor according to a thirteenth aspect of the invention is characterized in that, in addition to the configuration of the invention according to any one of the seventh to twelfth aspects, the welded portion is formed in a curved shape with a concave outer surface. To do.

また、請求項１４に係る発明のガスセンサの製造方法は、軸線方向に延びると共に、自身の先端側に被検出ガスを検出するための検出部を有する検出素子と、前記検出部を自身の先端から突出させつつ、前記検出素子の径方向周囲を取り囲む主体金具と、当該主体金具に固定され、前記検出素子の後端側の径方向周囲を取り囲む筒状の外筒とを有するガスセンサの製造方法において、前記主体金具は、径方向に拡径された鍔部と、当該鍔部よりも後端側に形成される筒部と、当該筒部の後端側に接続し、その筒部よりも縮径する縮径部とを有し、前記外筒の前記先端を、前記縮径部の径方向周囲を取り囲むように配置させつつ、前記筒部の後端向き面に当接させる外筒配置工程と、前記外筒の前記先端と前記主体金具の前記筒部との境界付近に向けて全周にわたってレーザ溶接を行い、前記外筒の前記先端と前記主体金具の前記筒部との間に跨って溶接部を形成する溶接工程とを有することを特徴とする。   According to a fourteenth aspect of the present invention, there is provided a gas sensor manufacturing method that includes a detection element that extends in an axial direction and has a detection unit for detecting a gas to be detected on its tip side, and the detection unit from its tip. In a method of manufacturing a gas sensor, comprising: a metal shell that surrounds the circumference of the detection element in a projecting manner; and a cylindrical outer cylinder that is fixed to the metal shell and surrounds the circumference of the detection element on the rear end side. The metal shell is connected to a flange portion radially expanded in diameter, a cylindrical portion formed on the rear end side of the flange portion, and a rear end side of the cylindrical portion, and is contracted more than the cylindrical portion. A diameter-reducing portion having an outer diameter, and an outer cylinder placement step of contacting the distal end surface of the tubular portion while arranging the distal end of the outer cylinder so as to surround the circumference of the diameter-reduced portion in the radial direction And the vicinity of the boundary between the tip of the outer cylinder and the cylindrical portion of the metal shell Perform laser welding over the entire circumference toward, and having a welding step of forming a weld across between the cylindrical portion of the tip and the metal shell of the outer cylinder.

また、請求項１５に係る発明のガスセンサの製造方法は、請求項１４に記載の発明の構成に加え、前記溶接工程では、前記溶接部の径方向における厚みが前記外筒の厚みよりも厚く形成されるように、前記外筒の前記先端と前記主体金具の前記筒部との境界付近に向けて全周にわたってレーザ溶接を行うことを特徴とする。   In the gas sensor manufacturing method according to the fifteenth aspect, in addition to the configuration of the invention according to the fourteenth aspect, in the welding step, the thickness of the welded portion in the radial direction is formed to be larger than the thickness of the outer cylinder. As described above, laser welding is performed over the entire circumference toward the vicinity of the boundary between the tip of the outer cylinder and the cylindrical portion of the metallic shell.

また、請求項１６に係る発明のガスセンサの製造方法は、請求項１４または１５に記載の発明の構成に加え、前記外筒配置工程後で前記溶接工程前に、前記外筒の前記先端と前記主体金具の前記筒部とに跨がるように、両者を外周側から加締めて加締め部を形成する加締め工程を有することを特徴とする。   In addition to the configuration of the invention of claim 14 or 15, the gas sensor manufacturing method of the invention according to claim 16 includes the tip of the outer cylinder and the tip of the outer cylinder after the outer cylinder arrangement process and before the welding process. It has a caulking process in which both are caulked from the outer peripheral side to form a caulking portion so as to straddle the cylindrical portion of the metal shell.

また、請求項１７に係る発明のガスセンサの製造方法は、軸線方向に延びると共に、自身の先端側に被検出ガスを検出するための検出部を有する検出素子と、前記検出部を自身の先端から突出させつつ、前記検出素子の径方向周囲を取り囲む主体金具と、当該主体金具に固定され、前記検出素子の後端側の径方向周囲を取り囲む筒状の外筒とを有するガスセンサの製造方法において、前記主体金具は、径方向に拡径された鍔部と、当該鍔部の後端側に形成される後端部とを有し、前記外筒の前記先端を、前記後端部の径方向周囲を取り囲むように配置させつつ、前記鍔部の後端向き面に当接させる外筒配置工程と、前記外筒の前記先端と前記主体金具の前記鍔部との境界付近に向けて全周にわたってレーザ溶接を行い、前記外筒の前記先端と前記主体金具の前記鍔部との間に跨って溶接部を形成する溶接工程とを有することを特徴とする。   The method for manufacturing a gas sensor according to the seventeenth aspect of the present invention includes a detection element that extends in the axial direction and has a detection unit for detecting a gas to be detected on its tip side, and the detection unit from its tip. In a method of manufacturing a gas sensor, comprising: a metal shell that surrounds the circumference of the detection element in a projecting manner; and a cylindrical outer cylinder that is fixed to the metal shell and surrounds the circumference of the detection element on the rear end side. The metal shell has a flange portion radially expanded in diameter and a rear end portion formed on the rear end side of the flange portion, and the tip of the outer cylinder is connected to the diameter of the rear end portion. An outer cylinder arranging step for contacting the rear end facing surface of the flange while arranging the outer periphery of the outer periphery, and the entire area toward the boundary between the tip of the outer cylinder and the flange of the metal shell. Laser welding is performed over the circumference, and the tip of the outer cylinder And having a welding step of forming a weld across between the flange portion of the serial metal shell.

また、請求項１８に係る発明のガスセンサの製造方法は、軸線方向に延びると共に、自身の先端側に被検出ガス中を検出するための検出部を有する検出素子と、前記検出部を自身の先端から突出させつつ、前記検出素子の径方向周囲を取り囲む主体金具と、当該主体金具に固定され、前記検出素子の後端側の径方向周囲を取り囲む筒状の外筒とを有するガスセンサの製造方法において、前記主体金具は、径方向に拡径された鍔部と、当該鍔部の後端側に形成される後端部とを有し、前記外筒の前記先端を、前記主体金具の前記鍔部とは離間しつつ前記後端部の径方向周囲を取り囲むように配置させる外筒配置工程と、前記外筒の前記先端と前記主体金具の前記後端部との境界付近に向けて全周にわたってレーザ溶接を行い、前記外筒の前記先端と前記主体金具の前記後端部との間に跨って溶接部を形成する溶接工程とを有することを特徴とする。   In addition, a gas sensor manufacturing method according to an eighteenth aspect of the present invention includes a detection element that extends in the axial direction and has a detection unit for detecting the inside of a gas to be detected on its front end side, and the detection unit on its front end. A gas sensor manufacturing method comprising: a metal shell that surrounds the periphery of the detection element in a radial direction while projecting from the tube; and a cylindrical outer cylinder that is fixed to the metal shell and surrounds the periphery of the detection element in the radial direction on the rear end side The metal shell has a flange portion radially expanded in diameter and a rear end portion formed on the rear end side of the flange portion, and the tip of the outer cylinder is connected to the metal shell. An outer cylinder arranging step of arranging the outer cylinder so as to surround the radial periphery of the rear end part while being separated from the flange part, and the entire process toward the vicinity of the boundary between the tip of the outer cylinder and the rear end part of the metal shell. Laser welding is performed over the circumference, and the tip of the outer cylinder And having a welding step of forming a weld across between the rear end portion of the metal shell and.

また、請求項１９に係る発明のガスセンサの製造方法は、請求項１７または１８に記載の発明の構成に加え、前記溶接工程では、前記溶接部の外表面が凹んだ曲面形状に形成されることを特徴とする。   According to a 19th aspect of the present invention, in addition to the configuration of the 17th or 18th aspect of the invention, in the welding process, the welding process is such that the outer surface of the welded portion is formed in a curved shape. It is characterized by.

請求項１に係る発明のガスセンサでは、外筒の先端が主体金具の後端部の少なくとも一部の径方向周囲を取り囲むように配置され、その外筒の先端と主体金具とに跨って溶接部が形成されて外筒と主体金具との接合がなされるが、さらにその溶接部が全周にわたって形成されることにより、主体金具の後端部の外周面と外筒の先端の内周面との間隙を外方に対し遮断した状態で密封することができる。するとガスセンサがその使用中に被水しても、その間隙への入口となり得る外筒の先端と主体金具の後端部との間が溶接部によって塞がれることとなるため、間隙内に水滴等が浸入することを防止することができる。従って、間隙内に浸入した水滴等が長期間にわたって間隙内に露出される溶接部と接触した状態が生ずることがなく、ひいては水滴等が長期間にわたって溶接部と接触した状態にあった場合に生じ得る腐食の発生を防止することができる。   In the gas sensor according to the first aspect of the present invention, the distal end of the outer cylinder is disposed so as to surround at least a part of the rear end portion of the metallic shell in the radial direction, and the welded portion straddles the distal end of the outer cylinder and the metallic shell. The outer cylinder and the metal shell are joined together, and the welded portion is formed over the entire circumference, so that the outer peripheral surface of the rear end portion of the metal shell and the inner peripheral surface of the front end of the outer cylinder It is possible to seal in a state in which the gap is blocked from the outside. Then, even if the gas sensor is flooded during use, the welded portion blocks the space between the front end of the outer cylinder that can be an entrance to the gap and the rear end of the metal shell. And the like can be prevented from entering. Therefore, a state in which water droplets or the like that have entered the gap does not come into contact with the welded portion exposed in the gap for a long period of time, and as a result, waterdrops or the like that have been in contact with the welded portion for a long time occurs. It is possible to prevent the occurrence of corrosion.

このように、主体金具の後端部と外筒の先端との間に跨る溶接部を全周にわたって形成するにあたって、請求項２に係る発明のように、主体金具の後端部を段状に形成し筒部と縮径部とを有するようにすれば、外筒の先端を、その縮径部に係合させつつ筒部に付き合わせることができ、外筒と主体金具との接合の際に両者の位置決めと仮固定を行いやすい。そして外筒と主体金具との接合を、例えばレーザ溶接を用いて行う場合、上記のように外筒の先端を主体金具の筒部に付き合わせ、その突き合わせ位置（外筒と主体金具との境界）を狙ってガスセンサの軸線方向と直交する方向からレーザを照射すれば、主体金具の溶融具合と外筒の溶融具合とをより均等な状態に近づけることができ、溶接部の形成による上記間隙の封止をより確実に行うことができる。もっとも、レーザの照射位置は上記突き合わせ位置よりも主体金具側に偏っていても、あるいは外筒側に偏っていても、レーザに溶融されて形成される溶接部が外筒と主体金具とに跨って形成されれば十分に、上記間隙の封止を行うことが可能である。   Thus, in forming the welded portion straddling between the rear end portion of the metal shell and the front end of the outer cylinder, the rear end portion of the metal shell is stepped like the invention according to claim 2. If it is formed and has a cylindrical portion and a reduced diameter portion, the tip of the outer cylinder can be brought into contact with the cylindrical portion while being engaged with the reduced diameter portion, and when the outer cylinder and the metal shell are joined. It is easy to position and temporarily fix both. When joining the outer cylinder and the metal shell, for example, using laser welding, the tip of the outer cylinder is brought into contact with the cylinder portion of the metal shell as described above, and the abutting position (the boundary between the outer cylinder and the metal shell) If the laser is irradiated from the direction orthogonal to the axial direction of the gas sensor, the melting state of the metal shell and the melting state of the outer cylinder can be brought closer to a uniform state, and the gap due to the formation of the welded portion can be brought closer. Sealing can be performed more reliably. However, even if the laser irradiation position is biased to the metal shell side or the outer cylinder side with respect to the abutting position, the welded portion formed by melting by the laser straddles the outer cylinder and the metal shell. If formed, the gap can be sufficiently sealed.

そして、請求項３に係る発明のように、溶接部の径方向における厚みが外筒の厚みよりも厚くなるように溶接部を形成することが望ましく、より具体的には、請求項４に係る発明のように、溶接部の径方向における厚みが外筒の厚みよりも２倍以上厚くなるようにレーザの出力を調整して溶接部を形成することが好ましい。このようにすれば、溶接部の形成において外筒と主体金具とを確実に溶融して互いの成分を混合でき、両者の接合強度を高め、主体金具の後端部の外周面と外筒の先端の内周面との間隙の封止を確実に行うことができる。   And like invention concerning Claim 3, it is desirable to form a welding part so that the thickness in the diameter direction of a welding part may become thicker than the thickness of an outer cylinder, More specifically, it concerns on Claim 4. As in the invention, it is preferable to form the welded portion by adjusting the output of the laser so that the thickness in the radial direction of the welded portion is twice or more thicker than the thickness of the outer cylinder. In this way, the outer cylinder and the metal shell can be reliably melted and mixed with each other in the formation of the welded portion, the joint strength between them can be increased, the outer peripheral surface of the rear end of the metal shell and the outer cylinder The gap between the tip and the inner peripheral surface can be reliably sealed.

また、請求項５に係る発明のように、形成された溶接部の先端が主体金具の鍔部の後端から離れていることが好ましく、より具体的に、軸線方向における溶接部の先端と鍔部の後端との間の距離が１ｍｍ以上離れていることが望ましい。外筒と主体金具との接合を、例えばレーザ溶接を用いて行う場合、外筒の先端と主体金具の筒部との突き合わせ位置（外筒と主体金具との境界）を狙ってレーザを照射することとなる。このとき、レーザの照射位置と主体金具の鍔部とが離れていれば、その作業を容易に行うことができ、その距離は、上記のように、形成された溶接部の先端が鍔部の後端から１ｍｍ以上離れていれば足りる。一方、形成された溶接部の先端と鍔部の後端との距離が１ｍｍ未満である場合、レーザの照射位置が鍔部に近いため、レーザが鍔部に当たらないようにしつつ、上記突き合わせ位置を狙ってガスセンサの軸線方向と直交する方向からレーザを照射するのは難しいことがある。レーザが鍔部にかかってしまった場合、主体金具の溶融具合と外筒の溶融具合とを均等な状態とするのが難しく、また、仕上がりの美観を損なう虞もあるため、レーザ照射時の照射角度を変更したり、照***度を高めたりする必要が生ずることがある。   Further, as in the invention according to claim 5, it is preferable that the tip of the formed welded part is separated from the rear end of the collar part of the metal shell, and more specifically, the tip of the welded part and the collar in the axial direction. It is desirable that the distance from the rear end of the part is 1 mm or more. When joining the outer cylinder and the metal shell using, for example, laser welding, the laser is irradiated aiming at the abutment position (boundary between the outer cylinder and the metal shell) between the tip of the outer cylinder and the cylindrical portion of the metal shell. It will be. At this time, if the laser irradiation position and the collar part of the metal shell are separated from each other, the operation can be easily performed, and the distance is such that the tip of the formed welded part is A distance of 1 mm or more from the rear end is sufficient. On the other hand, when the distance between the front end of the formed weld and the rear end of the collar is less than 1 mm, the laser irradiation position is close to the collar, so that the laser does not hit the collar and the butting position It may be difficult to irradiate the laser from the direction perpendicular to the axial direction of the gas sensor. If the laser is applied to the buttocks, it is difficult to achieve a uniform state of melting of the main metal shell and of the outer cylinder, and there is a risk that the aesthetic appearance of the finish may be impaired. It may be necessary to change the angle or increase the irradiation accuracy.

また、請求項６に係る発明のように、外筒の先端と主体金具の筒部とに跨るように両者を外周側から加締めることで、主体金具に対し外筒の仮固定を行うことができ、溶接部を形成する過程で主体金具と外筒との位置ずれの発生を防止し、両者を接続する溶接部が確実に両者を跨ぐ状態で形成されるようにすることができる。   Further, as in the invention according to claim 6, by temporarily crimping both from the outer peripheral side so as to straddle the tip of the outer cylinder and the cylindrical portion of the metallic shell, the outer cylinder can be temporarily fixed to the metallic shell. It is possible to prevent occurrence of displacement between the metal shell and the outer cylinder in the process of forming the welded portion, and to ensure that the welded portion connecting the two is formed across the two.

ところで溶接部は、請求項７に係る発明のように、外筒の先端を主体金具の鍔部に付き合わせるようにしつつ、両者を跨ぐように形成してもよい。このように、外筒の先端の内周面と主体金具の後端部の外周面との間の間隙への入口部分となり得る部位を溶接部で埋めることができれば、上記間隙の封止を確実に行うことができる。   By the way, as in the invention according to claim 7, the welded portion may be formed so as to straddle the both ends while attaching the tip of the outer cylinder to the flange portion of the metal shell. In this way, if the portion that can be the entrance portion to the gap between the inner peripheral surface at the front end of the outer cylinder and the outer peripheral surface of the rear end portion of the metal shell can be filled with the welded portion, the sealing of the gap is ensured. Can be done.

さらに請求項８に係る発明のように、外筒の先端に、径方向外側へ拡径する拡径部を有し、その拡径部と鍔部とに跨って溶接部を形成してもよい。より具体的に、拡径部は外筒の先端を径方向外側へ折り返した形態の部位であり、その拡径部の軸線方向の先端を主体金具の鍔部の後端に当接させ、拡径部の径方向先端と鍔部の後端との間にできた段差に、拡径部と鍔部とを跨ぐ溶接部を形成するものである。外筒の先端に拡径部を有しても、このように、外筒の先端と主体金具の鍔部との間に跨った溶接部が形成されれば、外筒の先端の内周面と主体金具の後端部の外周面との間の間隙への入口部分となり得る部位が溶接部で埋められるので、上記間隙の封止を確実に行うことができる。   Furthermore, like the invention which concerns on Claim 8, it has a diameter-expanded part which expands to a radial direction outer side in the front-end | tip of an outer cylinder, and a weld part may be formed ranging over the diameter-expanded part and a collar part. . More specifically, the enlarged-diameter portion is a portion in a form in which the front end of the outer cylinder is folded back radially outward, and the distal end in the axial direction of the enlarged-diameter portion is brought into contact with the rear end of the flange portion of the metal shell, thereby expanding the diameter. A weld that straddles the enlarged diameter portion and the flange portion is formed at a step formed between the radial tip of the diameter portion and the rear end of the flange portion. Even if it has an enlarged diameter portion at the tip of the outer cylinder, if a welded portion is formed between the tip of the outer cylinder and the flange of the metal shell, the inner peripheral surface of the tip of the outer cylinder Since the portion that can be an entrance portion to the gap between the metal shell and the outer peripheral surface of the rear end portion of the metal shell is filled with the welded portion, the gap can be reliably sealed.

ところで、外筒の先端と主体金具の鍔部とを跨ぐ溶接部を、例えばレーザ溶接を用いて形成する場合、請求項９に係る発明のように、径方向内側に向かうにつれ軸線方向先端側に延びるようにレーザを照射して溶接部を形成すれば、主体金具内部まで溶接部を形成することができ、外筒と主体金具との接合強度をより高めることができる。なお、外筒の先端と主体金具の鍔部との突き合わせ位置を含むように上記の向きにレーザを照射すればよい。   By the way, when forming the welded portion straddling the tip of the outer cylinder and the flange portion of the metal shell, for example, using laser welding, as in the invention according to claim 9, as it goes radially inward, toward the tip end in the axial direction. If the welded portion is formed by irradiating the laser so as to extend, the welded portion can be formed up to the inside of the metal shell, and the joint strength between the outer cylinder and the metal shell can be further increased. In addition, what is necessary is just to irradiate a laser in said direction so that the butting | matching position of the front-end | tip of an outer cylinder and the collar part of a metal shell may be included.

また、請求項１０に係る発明のように、外筒の先端を主体金具の鍔部と離間させた状態で、外筒の先端と主体金具の後端部との間に跨って溶接部を形成してもよい。このように、外筒の先端の内周面と主体金具の後端部の外周面との間の間隙への入口部分となり得る部位を溶接部で埋めることができれば、上記間隙の封止を確実に行うことができる。   Further, as in the invention according to claim 10, a welded portion is formed straddling between the front end of the outer cylinder and the rear end portion of the metal shell, with the front end of the outer cylinder being separated from the collar portion of the metal shell. May be. In this way, if the portion that can be the entrance portion to the gap between the inner peripheral surface at the front end of the outer cylinder and the outer peripheral surface of the rear end portion of the metal shell can be filled with the welded portion, the sealing of the gap is ensured. Can be done.

そして、外筒の先端と主体金具の後端部とを跨ぐ溶接部を、例えばレーザ溶接を用いて形成する場合、請求項１１に係る発明のように、径方向内側に向かうにつれ軸線方向後端側に延びるようにレーザを照射して溶接部を形成すれば、主体金具内部まで溶接部を形成することができ、外筒と主体金具との接合強度をより高めることができる。なお、外筒の先端と主体金具の後端部との突き合わせ位置を含むように、上記の向きにレーザを照射すればよい。   And when forming the welding part which straddles the front-end | tip of an outer cylinder, and the rear-end part of a main metal fitting, for example using laser welding, it is an axial direction rear end as it goes to radial direction inner side like the invention which concerns on Claim 11. If the welded portion is formed by irradiating the laser so as to extend to the side, the welded portion can be formed up to the inside of the metal shell, and the bonding strength between the outer cylinder and the metal shell can be further increased. In addition, what is necessary is just to irradiate a laser in said direction so that the butting | matching position of the front-end | tip of an outer cylinder and the rear-end part of a metal shell may be included.

なお、請求項１２に係る発明のように、溶接部を形成するにあたって、溶接部の径方向における厚みが外筒の厚みよりも厚くなるようすれば、溶接部の形成において確実に外筒と主体金具とを溶融して互いの成分を混合でき、両者の接合強度を高め、主体金具の後端部の外周面と外筒の先端の内周面との間隙の封止を確実に行うことができる。   As in the invention according to claim 12, when forming the welded portion, if the thickness in the radial direction of the welded portion is made larger than the thickness of the outer tube, the outer tube and the main body are reliably formed in the formation of the welded portion. It is possible to melt the metal fittings and mix each other's components, increase the joint strength between them, and reliably seal the gap between the outer peripheral surface of the rear end of the main metal fitting and the inner peripheral surface of the front end of the outer cylinder it can.

また、こうした形態の溶接部の形成は、外筒と主体金具との突き合わせ位置を望む、内向きに曲折する２面をその突き合わせ位置にて接合する形態となるため、請求項１３に係る発明のように、形成された溶接部の外表面が凹んだ曲面形状に形成されれば、外筒の先端と主体金具との間の間隙への入口部分を溶接部で封止する厚みを有することができ、間隙の封止をより確実に行うことができる。   Further, since the formation of the welded portion in such a form is a form in which two faces that are bent inward are desired at the abutting position, where the abutting position between the outer cylinder and the metal shell is desired, the invention according to claim 13 In this way, if the outer surface of the formed welded part is formed in a concave curved surface shape, it may have a thickness that seals the entrance part to the gap between the tip of the outer cylinder and the metal shell with the welded part. It is possible to seal the gap more reliably.

また、請求項１４に係る発明のガスセンサの製造方法では、外筒配置工程において、外筒の先端を主体金具の縮径部に係合させつつ筒部の後端側面に当接させるので、外筒と主体金具と位置決めと仮固定を行いやすい。この状態で溶接工程にて外筒と主体金具との境界付近に向けて全周にわたってレーザ溶接するので、外筒の先端と主体金具の筒部との間で確実に、両者を跨ぐ溶接部を形成することができる。このときのレーザの照射を軸線方向と直交する方向から行えば、主体金具の溶融具合と外筒の溶融具合とをより均等な状態に近づけることができ、溶接部の形成による上記間隙の封止をより確実に行うことができる。なお、レーザの照射は、外筒の先端と主体金具の筒部とを当接させた境界に向けて行うことが望ましいが、その境界よりも主体金具側に偏っていても、あるいは外筒側に偏っていても、レーザに溶融されて形成される溶接部が外筒と主体金具との間に跨って形成されれば十分に、上記間隙の封止を行うことが可能である。従ってレーザ溶接は、外筒の先端と主体金具の筒部との境界付近に照射するとよい。   In the gas sensor manufacturing method according to the fourteenth aspect of the present invention, in the outer cylinder arranging step, the front end of the outer cylinder is brought into contact with the rear end side surface of the cylindrical portion while being engaged with the reduced diameter portion of the metal shell. It is easy to position and temporarily fix the cylinder and metal shell. In this state, laser welding is performed over the entire circumference toward the vicinity of the boundary between the outer cylinder and the metallic shell in the welding process. Can be formed. If the laser irradiation at this time is performed from the direction orthogonal to the axial direction, the melting state of the main metal shell and the melting state of the outer cylinder can be brought closer to a uniform state, and the gap is sealed by forming the welded portion. Can be performed more reliably. The laser irradiation is preferably performed toward the boundary where the tip of the outer cylinder and the cylindrical portion of the metal shell are in contact with each other. Even if it is biased, the gap can be sufficiently sealed if the welded portion formed by being melted by the laser is formed across the outer cylinder and the metal shell. Therefore, laser welding is preferably performed near the boundary between the tip of the outer cylinder and the cylindrical portion of the metal shell.

このように、外筒の先端と主体金具の筒部との間で両者を跨ぐ溶接部を形成することで、主体金具の後端部の外周面と外筒の先端の内周面との間隙を外方に対し遮断した状態で密封することができる。するとガスセンサがその使用中に被水しても、その間隙への入口となり得る外筒の先端と主体金具の後端部との間が溶接部によって塞がれることとなるため、間隙内に水滴等が浸入することを防止することができる。従って、間隙内に浸入した水滴等が長期間にわたって間隙内に露出される溶接部と接触した状態が生ずることがなく、ひいては水滴等が長期間にわたって溶接部と接触した状態にあった場合に生じ得る腐食の発生を防止することができる。   In this way, the gap between the outer peripheral surface of the rear end portion of the metal shell and the inner peripheral surface of the front end of the outer tube is formed between the front end of the outer tube and the cylindrical portion of the metal shell. Can be sealed in a state of being blocked from the outside. Then, even if the gas sensor is flooded during use, the welded portion blocks the space between the front end of the outer cylinder that can be an entrance to the gap and the rear end of the metal shell. And the like can be prevented from entering. Therefore, a state in which water droplets or the like that have entered the gap does not come into contact with the welded portion exposed in the gap for a long period of time, and as a result, waterdrops or the like that have been in contact with the welded portion for a long time occurs. It is possible to prevent the occurrence of corrosion.

また、請求項１５に係る発明のように、溶接部の径方向における厚みが外筒の厚みよりも厚くなるように溶接部を形成すれば、その溶接部が、外筒の先端側と径方向内側とのそれぞれにおいて主体金具との間にて形成されるので、溶接部の形成による上記間隙の封止をさらに確実に行うことができる。   Further, as in the invention according to claim 15, if the welded portion is formed such that the thickness in the radial direction of the welded portion is thicker than the thickness of the outer cylinder, the welded portion is in the radial direction with respect to the distal end side of the outer cylinder. Since it is formed between the metal shell and the inner side, the gap can be more reliably sealed by forming the welded portion.

また、請求項１６に係る発明のように、外筒配置工程後で溶接工程前に加締め工程を行い、外筒の先端と主体金具の筒部とに跨るように両者を外周側から加締めれば、主体金具に対し外筒の仮固定を行うことができる。このようにすれば溶接工程において外筒との位置ずれが生ずることを防止し、両者を跨ぐ溶接部を確実に形成することができる。   Further, as in the invention according to claim 16, a caulking process is performed after the outer cylinder arranging process and before the welding process, and the two are caulked from the outer peripheral side so as to straddle the tip of the outer cylinder and the cylindrical portion of the metal shell. In this case, the outer cylinder can be temporarily fixed to the metal shell. If it does in this way, it can prevent that position shift with an outer cylinder arises in a welding process, and can form a welding part over both.

また、請求項１７に係る発明のように、外筒の先端に主体金具の後端部を係合させつつ、外筒の先端を主体金具の鍔部に当接させて両者を跨ぐ溶接部を形成すれば、外筒の先端の内周面と主体金具の後端部の外周面との間の間隙への入口部分となり得る部位すなわち外筒の先端と主体金具の鍔部との当接部分を溶接部で埋めることができ、上記間隙の封止を確実に行うことができる。   Further, as in the invention according to claim 17, the welded portion straddling the both ends of the outer cylinder is brought into contact with the flange portion of the metallic shell while the rear end portion of the metallic shell is engaged with the distal end of the outer cylinder. If formed, a portion that can be an entrance portion into the gap between the inner peripheral surface of the outer cylinder at the tip and the outer peripheral surface of the rear end of the metal shell, that is, a contact portion between the tip of the outer cylinder and the flange of the metal shell Can be filled with the welded portion, and the gap can be reliably sealed.

同様に、請求項１８に係る発明のように、外筒の先端に主体金具の後端部を係合させつつ、外筒の先端を主体金具の鍔部に対し離間させた状態で両者を跨ぐ溶接部を形成しても、外筒の先端の内周面と主体金具の後端部の外周面との間の間隙への入口部分となり得る部位すなわち外筒の先端と主体金具の後端部との境界部分を溶接部で埋めることができ、上記間隙の封止を確実に行うことができる。   Similarly, as in the invention according to claim 18, the rear end portion of the metallic shell is engaged with the distal end of the outer cylinder, and the both ends are straddled with the distal end of the outer cylinder separated from the collar portion of the metallic shell. Even if the welded portion is formed, a portion that can be an entrance portion to the gap between the inner peripheral surface of the front end of the outer cylinder and the outer peripheral surface of the rear end portion of the metal shell, that is, the front end of the outer cylinder and the rear end portion of the metal shell Can be filled with a welded portion, and the gap can be reliably sealed.

なお、こうした形態の溶接部の形成は、内向きに曲折する２面をその曲折位置にて接合する形態となるため、請求項１９に係る発明のように、形成された溶接部の外表面が凹んだ曲面形状に形成されれば、外筒の先端と主体金具の後端部との間の間隙への入口部分を溶接部で封止する厚みを有することができ、間隙の封止をより確実に行うことができる。   In addition, since the formation of the welded part in such a form is a form in which the two surfaces bent inward are joined at the bent position, the outer surface of the formed welded part is as in the invention according to claim 19. If it is formed in a concave curved surface shape, it can have a thickness that seals the entrance portion to the gap between the front end of the outer cylinder and the rear end portion of the metal shell with the welded portion, thereby further sealing the gap. It can be done reliably.

以下、本発明を具体化したガスセンサおよびその製造方法の一実施の形態について、図面を参照して説明する。まず、本発明に係るガスセンサの第１の実施の形態として、ガスセンサ１を例に、その構造について図１，図２を参照して説明する。図１は、ガスセンサ１の縦断面図である。図２は、図１の円Ａの部分を拡大してみたガスセンサ１の断面図である。なお、ガスセンサ１は自動車の排気管（図示外）に取り付けられて使用されるが、その際に排気管内に露出される側（図１の下側）を軸線Ｏ方向における先端側とし、反対側（図１の上側）を後端側として説明するものとする。   Hereinafter, an embodiment of a gas sensor and a manufacturing method thereof embodying the present invention will be described with reference to the drawings. First, as a first embodiment of a gas sensor according to the present invention, the structure of a gas sensor 1 will be described as an example with reference to FIGS. FIG. 1 is a longitudinal sectional view of the gas sensor 1. FIG. 2 is a cross-sectional view of the gas sensor 1 in which the portion of the circle A in FIG. 1 is enlarged. The gas sensor 1 is used by being attached to an exhaust pipe (not shown) of an automobile. At this time, the side exposed in the exhaust pipe (the lower side in FIG. 1) is the tip side in the direction of the axis O, and the opposite side. Assume that (the upper side in FIG. 1) is the rear end side.

図１に示すガスセンサ１は、自動車の排気管（図示外）に取り付けられ、内部に保持する検出素子１０の先端側に設けられた検出部１１が排気管内を流通する排気ガス中に晒されて、その排気ガス中の酸素濃度から排気ガスの空燃比を検出する、いわゆる全領域空燃比センサである。検出素子１０からは、排気ガスの空燃比がリーンの場合には、理論空燃比に対し余剰となる酸素の量に応じた検出値（電流値）が得られ、リッチの場合には未燃焼ガスを完全燃焼させるのに必要な酸素の量に応じた検出値（電流値）が得られる。これら検出値をもとに、図示しないセンサ制御回路にて排気ガスの空燃比が求められてＥＣＵ（電子制御ユニット）に対し出力され、空燃比フィードバック制御などに利用される。   A gas sensor 1 shown in FIG. 1 is attached to an exhaust pipe (not shown) of an automobile, and a detection unit 11 provided on the front end side of a detection element 10 held inside is exposed to exhaust gas flowing in the exhaust pipe. The so-called full-range air-fuel ratio sensor detects the air-fuel ratio of the exhaust gas from the oxygen concentration in the exhaust gas. When the air-fuel ratio of the exhaust gas is lean, a detection value (current value) corresponding to the amount of oxygen surplus with respect to the theoretical air-fuel ratio is obtained from the detection element 10, and when it is rich, unburned gas A detection value (current value) corresponding to the amount of oxygen necessary to completely burn the gas is obtained. Based on these detection values, the air-fuel ratio of the exhaust gas is obtained by a sensor control circuit (not shown) and output to an ECU (electronic control unit) for use in air-fuel ratio feedback control and the like.

まず、検出素子１０について説明する。検出素子１０は、公知にあるような軸線Ｏ方向に延びる細幅で板状の素子で、酸素濃度の検出を行うガス検出体と、そのガス検出体を早期活性化させるために加熱を行うヒータ体とを厚み方向に貼り合わせた積層体として一体化されたものである（図１では、紙面左右方向を厚み方向（板厚方向）、紙面表裏方向を幅方向として示している。）。ガス検出体は、ジルコニアを主体とする固体電解質体と白金を主体とする検出電極と（共に図示しない）から構成され、その検出電極は、検出素子１０の先端側の検出部１１内に配置されている。そして検出電極を排気ガスによる被毒から保護するため、検出素子１０の検出部１１には、その外周面を包むように保護層１５が形成されている。また、検出素子１０の後端側に設けられた電極部１２には、ガス検出体やヒータ体から電極を取り出すための５つの電極パッド１６（図１ではそのうちの２つの電極パッド１６を図示している。）が形成されている。なお、第１の実施の形態では、検出素子１０を本発明における「検出素子」として説明を行うが、厳密には、検出素子１０の構成としてヒータ体は必ずしも必要ではなく、ガス検出体が本発明の「検出素子」に相当する場合もある。   First, the detection element 10 will be described. The detection element 10 is a narrow and plate-like element extending in the direction of the axis O as is well known, and includes a gas detection body that detects the oxygen concentration, and a heater that heats the gas detection body for early activation. The body is integrated as a laminated body bonded in the thickness direction (in FIG. 1, the left-right direction on the paper surface is shown as the thickness direction (plate thickness direction), and the front-back direction on the paper surface is shown as the width direction). The gas detector is composed of a solid electrolyte body mainly composed of zirconia and a detection electrode mainly composed of platinum (both not shown), and the detection electrode is disposed in the detection section 11 on the distal end side of the detection element 10. ing. And in order to protect a detection electrode from poisoning by exhaust gas, the protective layer 15 is formed in the detection part 11 of the detection element 10 so that the outer peripheral surface may be wrapped. Further, the electrode portion 12 provided on the rear end side of the detection element 10 has five electrode pads 16 (two electrode pads 16 are shown in FIG. 1) for taking out the electrodes from the gas detection body and the heater body. Is formed). In the first embodiment, the detection element 10 is described as a “detection element” in the present invention. However, strictly speaking, a heater body is not necessarily required as the configuration of the detection element 10, and the gas detection body is not a main element. It may correspond to the “detection element” of the invention.

次に、フランジ部２４について説明する。検出素子１０の中央部１３のやや先端側には、自身の内部に検出素子１０を挿通させた有底筒状をなす金属製の金属カップ２０が配置されている。金属カップ２０は主体金具５０内に検出素子１０を保持するための保持部材であり、筒底の開口２５から検出素子１０の検出部１１が突出されている。また、筒底の縁部分の先端周縁部２３は、外周面にかけてテーパ状に形成されている。金属カップ２０内には、アルミナ製のセラミックリング２１と滑石粉末からなるシール材２２とが、それぞれ、自身に検出素子１０を挿通させた状態で収容されている。シール材２２は金属カップ２０内で押し潰されて細部に充填されており、これにより、金属カップ２０とセラミックリング２１とシール材２２とが一体となり、フランジ部２４として、検出素子１０の径方向周囲を取り囲む形態で検出素子１０に一体に組み付けられている。   Next, the flange portion 24 will be described. A metal cup 20 made of metal having a bottomed cylindrical shape with the detection element 10 inserted therein is disposed slightly on the front end side of the central portion 13 of the detection element 10. The metal cup 20 is a holding member for holding the detection element 10 in the metal shell 50, and the detection portion 11 of the detection element 10 protrudes from the opening 25 at the bottom of the cylinder. Moreover, the front-end | tip peripheral part 23 of the edge part of a cylinder bottom is formed in the taper shape over the outer peripheral surface. A ceramic ring 21 made of alumina and a sealing material 22 made of talc powder are accommodated in the metal cup 20 with the detection element 10 inserted therethrough. The sealing material 22 is crushed in the metal cup 20 to be filled in detail, whereby the metal cup 20, the ceramic ring 21, and the sealing material 22 are integrated and serve as the flange portion 24 in the radial direction of the detection element 10. The detection element 10 is integrally assembled so as to surround the periphery.

次に、主体金具５０について説明する。主体金具５０はガスセンサ１を自動車の排気管（図示外）に取り付け固定するためのものであり、内部に貫通孔５８が形成された筒状をなしている。検出素子１０はその中央部１３が、フランジ部２４ごと主体金具５０の貫通孔５８内にて保持されている。主体金具５０は、例えばＳＵＳ４３０等の低炭素鋼からなり、外周先端側に排気管への取り付け用のねじ山が形成された雄ねじ部５１を有する。この雄ねじ部５１よりも先端側には、後述するプロテクタ８が係合される先端係合部５６が形成されている。また、主体金具５０の外周中央には取り付け用の工具が係合する工具係合部５２が形成されている。そして、その工具係合部５２の先端面と雄ねじ部５１の後端との間には、排気管に取り付けた際のガス抜けを防止するためのガスケット５５が嵌挿されている。なお、工具係合部５２が、本発明における「鍔部」に相当する。   Next, the metal shell 50 will be described. The metal shell 50 is for attaching and fixing the gas sensor 1 to an exhaust pipe (not shown) of the automobile, and has a cylindrical shape in which a through hole 58 is formed. The center portion 13 of the detection element 10 is held in the through hole 58 of the metal shell 50 together with the flange portion 24. The metal shell 50 is made of, for example, low carbon steel such as SUS430, and has a male screw portion 51 in which a thread for attachment to the exhaust pipe is formed on the outer peripheral tip side. A distal end engaging portion 56 to which a protector 8 described later is engaged is formed on the distal end side of the male screw portion 51. Further, a tool engaging portion 52 with which a tool for attachment is engaged is formed at the center of the outer periphery of the metal shell 50. And between the front end surface of the tool engaging part 52 and the rear end of the external thread part 51, the gasket 55 for preventing the gas escape at the time of attaching to an exhaust pipe is inserted. Note that the tool engaging portion 52 corresponds to a “hook portion” in the present invention.

さらに、図２に示すように、工具係合部５２の後端側には、後述する外筒６５の先端６６が係合される後端係合部５７が形成されている。第１の実施の形態において、後端係合部５７は、工具係合部５２側の筒部５７１と、その筒部５７１より後端側で、筒部５７１よりも縮径された縮径部５７２とからなる段状に形成されている。両者の段部からなる面５７４（以下、「後端向き面」５７４という。図２では溶接前の後端向き面５７４の位置が点線で示されている。）の径方向における大きさは、後述する外筒６５の厚みとほぼ同等に構成されている。そして、後端係合部５７よりもさらに後端側に、主体金具５０内に検出素子１０を加締め保持するための加締め部５３が形成されている。なお、後端係合部５７が、本発明における「後端部」に相当する。   Further, as shown in FIG. 2, a rear end engaging portion 57 is formed on the rear end side of the tool engaging portion 52 to be engaged with a front end 66 of an outer cylinder 65 described later. In the first embodiment, the rear end engaging portion 57 includes a cylindrical portion 571 on the tool engaging portion 52 side, and a reduced diameter portion that is smaller in diameter than the cylindrical portion 571 on the rear end side from the cylindrical portion 571. 572. The size in the radial direction of the surface 574 (hereinafter referred to as “rear end facing surface” 574. In FIG. 2, the position of the rear end facing surface 574 before welding is indicated by a dotted line) consisting of both stepped portions is as follows. The thickness of the outer cylinder 65 described later is substantially the same. A caulking portion 53 for caulking and holding the detection element 10 in the metal shell 50 is formed further on the rear end side than the rear end engaging portion 57. The rear end engaging portion 57 corresponds to the “rear end portion” in the present invention.

また、図１に示すように、主体金具５０の貫通孔５８の内周で雄ねじ部５１付近には、段状をなす段部５４が形成されている。この段部５４には、検出素子１０と一体となったフランジ部２４を構成する金属カップ２０の先端周縁部２３が係止されている。さらに、主体金具５０の内周には滑石粉末からなるシール材２６が、自身に検出素子１０を挿通させた状態で、フランジ部２４の後端側から装填されている。そして、シール材２６を後端側から押さえるように、筒状のスリーブ２７が主体金具５０内に嵌め込まれている。スリーブ２７の後端側外周には段状をなす肩部２８が形成されており、その肩部２８には、円環状の加締めパッキン２９が配置されている。この状態で主体金具５０の加締め部５３が、加締めパッキン２９を介してスリーブ２７の肩部２８を先端側に向けて押圧するように加締められている。シール材２６は主体金具５０内で押し潰されて細部にわたって充填されており、このシール材２６と、金属カップ２０内にあらかじめ装填されたシール材２２とによって、フランジ部２４および検出素子１０が主体金具５０内で位置決められて保持されている。主体金具５０内の気密は加締め部５３とスリーブ２７の肩部２８との間に介在される加締めパッキン２９によって維持され、燃焼ガスの流出が防止される。   Further, as shown in FIG. 1, a stepped portion 54 having a step shape is formed in the vicinity of the male screw portion 51 on the inner periphery of the through hole 58 of the metal shell 50. The step 54 is engaged with the peripheral edge 23 of the metal cup 20 that forms the flange 24 integrated with the detection element 10. Further, a sealing material 26 made of talc powder is loaded on the inner periphery of the metal shell 50 from the rear end side of the flange portion 24 in a state where the detection element 10 is inserted through the metal shell 50 itself. A cylindrical sleeve 27 is fitted into the metal shell 50 so as to hold the sealing material 26 from the rear end side. A shoulder portion 28 having a step shape is formed on the outer periphery of the rear end side of the sleeve 27, and an annular caulking packing 29 is disposed on the shoulder portion 28. In this state, the crimping portion 53 of the metal shell 50 is crimped so as to press the shoulder portion 28 of the sleeve 27 toward the distal end side via the crimping packing 29. The sealing material 26 is crushed in the metal shell 50 and filled in details, and the flange portion 24 and the detection element 10 are mainly composed of the sealing material 26 and the sealing material 22 loaded in advance in the metal cup 20. It is positioned and held in the metal fitting 50. The airtightness in the metal shell 50 is maintained by the caulking packing 29 interposed between the caulking portion 53 and the shoulder portion 28 of the sleeve 27, and the outflow of combustion gas is prevented.

次に、ガスセンサ１の主体金具５０より後端側の構造について説明する。主体金具５０後端（加締め部５３）からは、内部に保持する検出素子１０の電極部１２を含む後端側の部分が突出されている。その電極部１２には、絶縁性セラミックスからなる筒状のセパレータ６０が被せられている。セパレータ６０は、検出素子１０の電極部１２に形成された複数の電極パッド１６のそれぞれに接触（電気的に接続）させる５つの接続端子６１（図１ではそのうちの２つの接続端子６１を図示している。）を内部に保持している。また、各接続端子６１と、各接続端子６１に接続されてガスセンサ１の外部に引き出される５本のリード線６４（図１ではそのうちの３本のリード線６４を図示している。）と各接続部分もセパレータ６０内に収容されて保護されている。   Next, the structure of the rear end side of the metal shell 50 of the gas sensor 1 will be described. From the rear end (caulking portion 53) of the metal shell 50, a portion on the rear end side including the electrode portion 12 of the detection element 10 held inside protrudes. The electrode portion 12 is covered with a cylindrical separator 60 made of insulating ceramics. The separator 60 includes five connection terminals 61 (in FIG. 1, two connection terminals 61 are shown) that are brought into contact (electrically connected) with each of the plurality of electrode pads 16 formed on the electrode portion 12 of the detection element 10. Is held inside. Further, each connection terminal 61, five lead wires 64 connected to each connection terminal 61 and drawn out of the gas sensor 1 (three lead wires 64 are shown in FIG. 1) and each. The connecting portion is also accommodated in the separator 60 and protected.

前述した外筒６５はステンレス（例えばＳＵＳ３０４）製で筒状をなし、主体金具５０の後端側に取り付けられ、主体金具５０の後端から露出される検出素子１０の電極部１２やセパレータ６０の周囲を覆って保護するものである。図２に示すように、外筒６５は、自身の先端６６の内周面６８を、主体金具５０の後端係合部５７の縮径部５７２の外周面５７３に対向させるようにして、後端係合部５７に係合されている。この状態で、外筒６５の先端面６９（図２では溶接前の先端面６９の位置が点線で示されている。）と後端係合部５７の後端向き面５７４との突き合わせ位置付近（矢印Ｂで示す両者の境界付近）を跨ぐように、先端６６から筒部５７１にかけての範囲が、外周側から周方向に一周にわたってリング状に加締められ、加締め部６７として形成されている。さらに、この加締め部６７において、上記した矢印Ｂで示す部位付近を狙い、外筒６５の周方向に一周にわたって例えば公知のＹＡＧレーザを照射することにより、主体金具５０の筒部５７１と外筒６５の先端６６とを接合するレーザ溶接が施されている。レーザの照射によって、軸線Ｏ方向に先端６６から筒部５７１にかけての範囲が溶融し、両者を跨ぐ溶接部９９が形成されることにより、筒部５７１と先端６６とが接合されている。この溶接部９９は、ガスセンサ１の径方向における厚み（図２において矢印Ｃで示す大きさ）が、少なくとも外筒６５の厚み（図２において矢印Ｄで示す大きさ）よりも大きくなるようにレーザ溶接時の出力が調整されて、形成されている。より具体的には、形成された溶接部９９の厚みが、ガスセンサ１の径方向において、外筒６５の厚みの２倍以上となるように、レーザの出力が調整される。このような厚み（深さ）を有する溶接部９９を形成することにより、外筒６５と主体金具５０とを確実に溶融して互いの成分を混合でき、両者の接合強度を高めることができる。   The above-described outer cylinder 65 is made of stainless steel (for example, SUS304) and has a cylindrical shape. The outer cylinder 65 is attached to the rear end side of the metal shell 50 and is exposed from the rear end of the metal shell 50 and includes the electrode portion 12 of the detection element 10 and the separator 60. It covers and protects the surroundings. As shown in FIG. 2, the outer cylinder 65 is configured so that the inner peripheral surface 68 of its own tip 66 is opposed to the outer peripheral surface 573 of the reduced diameter portion 572 of the rear end engaging portion 57 of the metal shell 50. The end engaging portion 57 is engaged. In this state, the vicinity of the abutting position between the front end surface 69 of the outer cylinder 65 (the position of the front end surface 69 before welding is indicated by a dotted line in FIG. 2) and the rear end facing surface 574 of the rear end engaging portion 57. A range from the tip 66 to the cylindrical portion 571 is crimped in a ring shape from the outer peripheral side to the circumferential direction so as to straddle (near the boundary between both indicated by the arrow B), and is formed as a crimped portion 67. . Furthermore, in this caulking portion 67, by aiming near the portion indicated by the arrow B described above and irradiating, for example, a known YAG laser in the circumferential direction of the outer cylinder 65, the cylindrical portion 571 and the outer cylinder of the metal shell 50 are irradiated. Laser welding for joining the tip 66 of 65 is performed. The range from the tip 66 to the tube portion 571 is melted in the direction of the axis O by the laser irradiation, and a welded portion 99 is formed across the two, whereby the tube portion 571 and the tip 66 are joined. The welded portion 99 is a laser so that the thickness of the gas sensor 1 in the radial direction (the size indicated by the arrow C in FIG. 2) is at least larger than the thickness of the outer cylinder 65 (the size indicated by the arrow D in FIG. 2). The output at the time of welding is adjusted and formed. More specifically, the laser output is adjusted so that the thickness of the formed welded portion 99 is at least twice the thickness of the outer cylinder 65 in the radial direction of the gas sensor 1. By forming the weld 99 having such a thickness (depth), the outer cylinder 65 and the metal shell 50 can be reliably melted and the components of each other can be mixed, and the joint strength between them can be increased.

なお、溶接部９９は、軸線Ｏ方向において、自身の先端の位置と主体金具５０の工具係合部５２の後端の位置との間の距離（図２において矢印Ｅで示す大きさ）が３ｍｍであり、１ｍｍ以上となる位置に形成されている。   The weld 99 has a distance of 3 mm between the position of its tip and the position of the rear end of the tool engaging portion 52 of the metal shell 50 in the axis O direction (the size indicated by the arrow E in FIG. 2). And is formed at a position of 1 mm or more.

また、図１に示すように、外筒６５とセパレータ６０との間の間隙には、金属製で筒状の保持金具７０が配設されている。保持金具７０は自身の後端を内側に折り曲げて構成した支持部７１を有し、自身の内部に挿通されるセパレータ６０の後端側外周に鍔状に設けられた太径部６２を支持部７１に係止させて、セパレータ６０を支持している。この状態で、保持金具７０が配置された部分の外筒６５の外周面が加締められ、セパレータ６０を支持した保持金具７０が外筒６５内に固定されている。   In addition, as shown in FIG. 1, a metal-made cylindrical holding metal fitting 70 is disposed in the gap between the outer cylinder 65 and the separator 60. The holding metal fitting 70 has a support portion 71 formed by bending its rear end inward, and supports a large-diameter portion 62 provided in a bowl shape on the outer periphery of the rear end side of the separator 60 inserted into itself. The separator 60 is supported by being engaged with 71. In this state, the outer peripheral surface of the outer cylinder 65 where the holding metal fitting 70 is disposed is crimped, and the holding metal fitting 70 that supports the separator 60 is fixed in the outer cylinder 65.

そして外筒６５の後端側の開口には、フッ素系ゴム製のグロメット７５が嵌合されている。グロメット７５は複数の挿通孔７６を有し、各挿通孔７６に、セパレータ６０から引き出された複数のリード線６４が気密に挿通されている。この状態でグロメット７５は、セパレータ６０を先端側に押圧しつつ、外筒６５の外周から加締められて、外筒６５の後端に固定されている。   A fluorine rubber grommet 75 is fitted into the opening on the rear end side of the outer cylinder 65. The grommet 75 has a plurality of insertion holes 76, and a plurality of lead wires 64 drawn from the separator 60 are inserted into the insertion holes 76 in an airtight manner. In this state, the grommet 75 is crimped from the outer periphery of the outer cylinder 65 while pressing the separator 60 toward the front end side, and is fixed to the rear end of the outer cylinder 65.

次に、ガスセンサ１の主体金具５０より先端側の構造について説明する。主体金具５０の先端（先端係合部５６）からは、内部に保持する検出素子１０の検出部１１が突出されている。この先端係合部５６には、検出素子１０の検出部１１を、排気ガス中のデポジット（燃料灰分やオイル成分など被毒性の付着物質）による汚損や被水などによる折損等から保護するためのプロテクタ８が嵌められ、スポット溶接やレーザ溶接によって固定されている。プロテクタ８は、有底筒状の内側プロテクタ９０と、内側プロテクタ９０の外周面との間に空隙を有した状態でその径方向周囲を取り囲む筒状の外側プロテクタ８０とから構成される２重構造を有する。   Next, the structure of the front end side of the metal shell 50 of the gas sensor 1 will be described. The detection portion 11 of the detection element 10 held inside protrudes from the tip (tip engagement portion 56) of the metal shell 50. The tip engaging portion 56 protects the detecting portion 11 of the detecting element 10 from contamination caused by deposits (toxic substances such as fuel ash and oil components) in exhaust gas, breakage due to water, and the like. A protector 8 is fitted and fixed by spot welding or laser welding. The protector 8 is a double structure constituted by a bottomed cylindrical inner protector 90 and a cylindrical outer protector 80 that surrounds the periphery in the radial direction with a gap between the outer peripheral surface of the inner protector 90. Have

内側プロテクタ９０には、周壁９２の後端側に複数の内側導入孔９５と、周壁９２の先端側に複数の水抜き孔９６と、底壁９３（先端側の壁部）に排出口９７とが開口されている。そして開口端側（後端側）の基端部９１が主体金具５０の先端係合部５６の外周に係合され、その状態で外周を一周してレーザ溶接が施されており、内側プロテクタ９０が主体金具５０に固定されている。   The inner protector 90 includes a plurality of inner introduction holes 95 on the rear end side of the peripheral wall 92, a plurality of drain holes 96 on the front end side of the peripheral wall 92, and a discharge port 97 on the bottom wall 93 (wall portion on the front end side). Is open. The base end portion 91 on the opening end side (rear end side) is engaged with the outer periphery of the distal end engaging portion 56 of the metal shell 50, and in this state, laser welding is performed around the outer periphery. Is fixed to the metal shell 50.

また、外側プロテクタ８０には、周壁８２の先端側に複数の外側導入孔８５が開口されている。そして、開口端側の基端部８１が内側プロテクタ９０の基端部９１の外周に係合され、その状態で外周にスポット溶接が施されており、外側プロテクタ８０もまた内側プロテクタ９０を介して主体金具５０に固定されている。さらに、外側プロテクタ８０と内側プロテクタ９０との間の空隙を閉じるように、外側プロテクタ８０の先端部８３が内側プロテクタ９０の周壁９２に向けて内側に折り曲げられている。   Further, the outer protector 80 has a plurality of outer introduction holes 85 opened on the distal end side of the peripheral wall 82. Then, the base end portion 81 on the opening end side is engaged with the outer periphery of the base end portion 91 of the inner protector 90, and spot welding is performed on the outer periphery in this state, and the outer protector 80 is also connected via the inner protector 90. It is fixed to the metal shell 50. Furthermore, the tip 83 of the outer protector 80 is bent inward toward the peripheral wall 92 of the inner protector 90 so as to close the gap between the outer protector 80 and the inner protector 90.

外側プロテクタ８０と内側プロテクタ９０との間の空隙は、外側導入孔８５を介して外部から導入される排気ガスに、内側プロテクタ９０の周壁９２の外周を取り囲む状態で旋回流を生じさせ、ガス成分と水分とに分離するために設けられている。ガス成分は内側導入孔９５から内側プロテクタ９０内に導入され、検出素子１０に接触し、排出口９７から外部に排出される一方で、水分は、水抜き孔９６から内側プロテクタ９０内に進入し、排出口９７から外部に排出されるように構成されている。この構成により、検出素子１０の検出部１１は、排気ガス中のデポジットによる汚損や、被水に起因する熱衝撃による折損等から保護されている。   The gap between the outer protector 80 and the inner protector 90 causes the exhaust gas introduced from the outside through the outer introduction hole 85 to generate a swirling flow in a state of surrounding the outer periphery of the peripheral wall 92 of the inner protector 90, and thereby the gas component It is provided to separate water and moisture. The gas component is introduced into the inner protector 90 from the inner introduction hole 95, contacts the detection element 10, and is discharged to the outside from the discharge port 97, while moisture enters the inner protector 90 from the drain hole 96. , And is configured to be discharged from the discharge port 97 to the outside. With this configuration, the detection unit 11 of the detection element 10 is protected from contamination due to deposits in the exhaust gas, breakage due to thermal shock caused by moisture, and the like.

ところで前述したように、第１の実施の形態のガスセンサ１では、主体金具５０と外筒６５との接合が外筒６５の周方向に一周にわたるレーザ溶接により行われている。そのレーザ溶接によって形成された溶接部９９は、筒部５７１と先端６６との間にて両者が溶融されることによって両者を跨いで形成され、両者を接合している。このようなガスセンサ１の構成を実現可能な製造方法について、図１〜図３を参照して説明する。図３は、ガスセンサ１の製造過程を示す図である。なお、以下では、ガスセンサ１を構成する主体金具５０と外筒６５との接合の過程を中心に説明し、ガスセンサ１のその他の部位の製造過程については公知であるため、省略あるいは簡略化して説明するものとする。   Incidentally, as described above, in the gas sensor 1 of the first embodiment, the metal shell 50 and the outer cylinder 65 are joined by laser welding over one circumference in the circumferential direction of the outer cylinder 65. The welded portion 99 formed by the laser welding is formed so as to straddle the two by melting between the cylindrical portion 571 and the tip 66, and joins them together. A manufacturing method capable of realizing such a configuration of the gas sensor 1 will be described with reference to FIGS. FIG. 3 is a diagram illustrating a manufacturing process of the gas sensor 1. In the following, the process of joining the metal shell 50 and the outer cylinder 65 constituting the gas sensor 1 will be mainly described, and the manufacturing process of other parts of the gas sensor 1 is well-known, so that the description is omitted or simplified. It shall be.

［金具形成工程］
ガスセンサ１の製造過程において、主体金具５０は以下のように作製される。まず、ＳＵＳ４３０等の低炭素鋼材からなるパイプ状の鋼材が冷間鍛造機（図示外）にセットされ、押出成形等の鍛造加工が施される。そして切削機（図示外）を用い、外周面や、貫通孔５８となる筒孔内の切削加工が行われる。そして転造ダイス（図示外）を用い、雄ねじ部５１にねじ山が転造されて主体金具５０が完成する。 [Metal forming process]
In the manufacturing process of the gas sensor 1, the metal shell 50 is manufactured as follows. First, a pipe-shaped steel material made of a low carbon steel material such as SUS430 is set in a cold forging machine (not shown) and subjected to forging such as extrusion. Then, a cutting machine (not shown) is used to cut the outer peripheral surface and the inside of the cylindrical hole serving as the through hole 58. Then, using a rolling die (not shown), a thread is rolled on the male screw portion 51 to complete the metal shell 50.

［各部組立工程］
一方、図１に示す検出素子１０は、固体電解質体や電極、絶縁体等を積層してなる未焼成のガス検出体と未焼成のヒータ体とを厚み方向（板厚方向）に積層した状態で焼成し、その焼成体の検出部１１に保護層１５を形成することにより、細長い板状の素子として作製される。この検出素子１０に、セラミックリング２１とシール材２２を収容した金属カップ２０が検出素子１０の電極部１２側から嵌め込むように取り付けられ、中央部１３のやや先端側に配置される。その状態でシール材２２がセラミックリング２１側に押圧され、押し潰されることにより金属カップ２０内の隙間を埋め、検出素子１０とフランジ部２４とが一体となる。 [Each part assembly process]
On the other hand, the detection element 10 shown in FIG. 1 is a state in which an unfired gas detection body formed by laminating a solid electrolyte body, an electrode, an insulator, and the like and an unfired heater body are laminated in the thickness direction (plate thickness direction). And a protective layer 15 is formed on the detection part 11 of the fired body, thereby producing an elongated plate-like element. A metal cup 20 containing a ceramic ring 21 and a sealing material 22 is attached to the detection element 10 so as to be fitted from the electrode part 12 side of the detection element 10, and is arranged slightly on the front end side of the central part 13. In this state, the sealing material 22 is pressed toward the ceramic ring 21 side and is crushed to fill a gap in the metal cup 20, so that the detection element 10 and the flange portion 24 are integrated.

このフランジ部２４と一体となった検出素子１０は、図３に示すように、別工程で作製されたプロテクタ８が先端係合部５６に接合された主体金具５０の貫通孔５８内に配置される。さらに検出素子１０に、電極部１２側からシール材２６、スリーブ２７およびパッキン２９（図１参照）が挿通される。そして主体金具５０の加締め部５３が加締められることにより、押し潰されたシール材２６が主体金具５０と検出素子１０との間隙を埋め、主体金具５０内で検出素子１０が保持される。また、別工程において、ＳＵＳ３０４等のステンレスから外筒６５が筒状に形成される。この外筒６５内には、予めリード線６４が接続された接続端子６１を収容したセパレータ６０と、そのセパレータ６０を保持する保持金具７０と、グロメット７５とが配置され（図１参照）、外筒６５の外周面が加締められることにより外筒６５内に固定される。   As shown in FIG. 3, the detection element 10 integrated with the flange portion 24 is disposed in the through hole 58 of the metal shell 50 in which the protector 8 manufactured in a separate process is joined to the tip engagement portion 56. The Further, a sealing material 26, a sleeve 27, and a packing 29 (see FIG. 1) are inserted into the detection element 10 from the electrode portion 12 side. When the crimping portion 53 of the metal shell 50 is crimped, the squeezed seal material 26 fills the gap between the metal shell 50 and the detection element 10, and the detection element 10 is held in the metal shell 50. In another process, the outer cylinder 65 is formed in a cylindrical shape from stainless steel such as SUS304. In the outer cylinder 65, a separator 60 that accommodates a connection terminal 61 to which a lead wire 64 is connected in advance, a holding metal fitting 70 that holds the separator 60, and a grommet 75 are disposed (see FIG. 1). The outer peripheral surface of the cylinder 65 is fixed in the outer cylinder 65 by caulking.

［外筒配置工程］
そして図３に示すように、この外筒６５が、内部に検出素子１０の電極部１２を含む後端側の部分を収容するように主体金具５０の後端側から被せられる。このとき、外筒６５の先端面６９が、主体金具５０の後端係合部５７の筒部５７１と縮径部５７２との間の後端向き面５７４に当接され、図２に示したように、先端６６の内周面６８と縮径部５７２の外周面５７３とが対向して配置される。 [Outer cylinder placement process]
As shown in FIG. 3, the outer cylinder 65 is covered from the rear end side of the metal shell 50 so as to accommodate the rear end side portion including the electrode portion 12 of the detection element 10 therein. At this time, the front end surface 69 of the outer cylinder 65 is brought into contact with the rear end facing surface 574 between the cylindrical portion 571 and the reduced diameter portion 572 of the rear end engaging portion 57 of the metal shell 50, as shown in FIG. As described above, the inner peripheral surface 68 of the tip 66 and the outer peripheral surface 573 of the reduced diameter portion 572 are arranged to face each other.

［加締め工程］
次に、図３に示すように、先端面６９と後端向き面５７４との突き合わせ位置付近（図２に矢印Ｂで示した両者の境界付近）を跨ぐように、主体金具５０の後端係合部５７の筒部５７１から外筒６５の先端６６にかけての範囲が、矢印Ｍで示すように、周方向に一周にわたってリング状に加締められ、加締め部６７として形成される。この加締めによって、外筒６５は主体金具５０に仮固定された状態となる。 [Casting process]
Next, as shown in FIG. 3, the rear end portion of the metal shell 50 is straddled so as to straddle the vicinity of the abutting position between the front end surface 69 and the rear end facing surface 574 (near the boundary between both indicated by arrow B in FIG. 2). A range from the cylindrical portion 571 of the joint portion 57 to the distal end 66 of the outer tube 65 is caulked in a ring shape over the entire circumference as shown by an arrow M, and is formed as a caulking portion 67. By this caulking, the outer cylinder 65 is temporarily fixed to the metal shell 50.

［溶接工程］
さらに、この加締め部６７において、外筒６５の先端面６９付近（図２に矢印Ｂで示した部位付近）を狙い、矢印Ｌで示すように、外筒６５の周方向に一周にわたってレーザ溶接が行われる。このとき、外筒６５の溶融具合と主体金具５０の溶融具合とを略均等とするためレーザは軸線Ｏ方向と直交する方向から照射される。ここで、前述したように、軸線Ｏ方向における溶接部９９の先端の位置と主体金具５０の工具係合部５２の後端の位置との間の距離（図２において矢印Ｅで示す大きさ）が１ｍｍ以上となる位置に溶接部９９が形成されるように、外筒６５の先端面６９と後端向き面５７４との突き合わせ位置が位置決めされている。つまり、レーザの照射位置と工具係合部５２とは離れており、レーザを軸線Ｏ方向と直交する方向から照射するにあたって、その作業を容易に行うことができる。このレーザ溶接によって軸線Ｏ方向に筒部５７１から先端６６にかけての部位が溶融し、筒部５７１と先端６６とを跨ぐ溶接部９９が形成されて両者が接合され、ガスセンサ１が完成する。 [Welding process]
Further, in this caulking portion 67, laser welding is performed over the entire circumference of the outer cylinder 65 as indicated by an arrow L, aiming near the tip surface 69 of the outer cylinder 65 (in the vicinity of the portion indicated by the arrow B in FIG. 2). Is done. At this time, the laser is irradiated from a direction orthogonal to the direction of the axis O in order to make the melting condition of the outer cylinder 65 and the melting condition of the metal shell 50 substantially equal. Here, as described above, the distance between the position of the tip of the welded portion 99 in the direction of the axis O and the position of the rear end of the tool engaging portion 52 of the metal shell 50 (the size indicated by the arrow E in FIG. 2). The abutting position between the front end surface 69 and the rear end facing surface 574 of the outer cylinder 65 is positioned so that the weld 99 is formed at a position where the distance is 1 mm or more. That is, the laser irradiation position and the tool engaging portion 52 are separated from each other, and the operation can be easily performed when the laser is irradiated from the direction orthogonal to the axis O direction. By this laser welding, a portion from the tube portion 571 to the tip 66 is melted in the direction of the axis O, and a welded portion 99 straddling the tube portion 571 and the tip 66 is formed, and both are joined, and the gas sensor 1 is completed.

このように作製される第１の実施の形態のガスセンサ１では、図２に示すように、先端６６と筒部５７１との間で両者を跨ぐ溶接部９９が形成されたことにより、主体金具５０の筒部５７１の外周面５７３と外筒６５の先端６６の内周面６８との間の間隙が外方と遮断された状態に密封される。従ってガスセンサ１の使用の際にガスセンサ１が被水しても、溶接部９９によって、筒部５７１の外周面５７３と先端６６の内周面６８との間の間隙に水滴等が浸入することがない。つまり、先端６６の内周面６８と筒部５７１の外周面５７３との間隙への入口部分となり得る外筒６５の先端面６９と後端係合部５７の後端向き面５７４との間の間隙が、溶接部９９が形成されたことによって封止される。このため、溶接部９９と主体金具５０との界面に長期間水滴等が接触した場合に生じやすい腐食の発生を防止することができる。なお、筒部５７１の外周面において溶接部９９との界面が露出されており、その部分に水滴等が付着することもあるが、上記間隙に入り込んだ場合とは異なり広い面積をもって外気に接触した状態となるため、水滴等が揮発されやすく、上記のような腐食を生じにくい。   In the gas sensor 1 according to the first embodiment manufactured as described above, as shown in FIG. 2, the weld metal 99 is formed between the tip 66 and the cylindrical portion 571, thereby forming the metal shell 50. The gap between the outer peripheral surface 573 of the cylindrical portion 571 and the inner peripheral surface 68 of the tip 66 of the outer cylinder 65 is sealed in a state where it is blocked from the outside. Therefore, even when the gas sensor 1 is flooded when the gas sensor 1 is used, the weld 99 may cause water droplets or the like to enter the gap between the outer peripheral surface 573 of the cylindrical portion 571 and the inner peripheral surface 68 of the tip 66. Absent. That is, between the front end surface 69 of the outer cylinder 65 and the rear end facing surface 574 of the rear end engaging portion 57 which can be an entrance portion into the gap between the inner peripheral surface 68 of the front end 66 and the outer peripheral surface 573 of the cylindrical portion 571. The gap is sealed when the weld 99 is formed. For this reason, generation | occurrence | production of the corrosion which is easy to occur when a water drop etc. contact the interface of the welding part 99 and the metal shell 50 for a long period of time can be prevented. In addition, the interface with the welded portion 99 is exposed on the outer peripheral surface of the cylindrical portion 571, and water droplets or the like may adhere to the portion, but unlike the case where it enters the gap, it contacts the outside air with a wide area. Since it is in a state, water droplets and the like are easily volatilized, and the above-described corrosion hardly occurs.

また、主体金具５０の後端係合部５７と外筒６５の先端６６との間で両者を跨ぐ溶接部９９を形成するにあたって、主体金具５０の後端係合部５７を筒部５７１と縮径部５７２とを有する段状に形成すれば、外筒６５の先端６６を、その縮径部５７２に係合させつつ筒部５７１に付き合わせることができ、外筒６５と主体金具５０との接合の際に両者の位置決めと仮固定を行いやすい。そして外筒６５と主体金具５０との接合を、例えばレーザ溶接を用いて行う場合、上記のように外筒６５の先端６６を主体金具５０の筒部５７１に付き合わせ、その突き合わせ位置（外筒６５と主体金具５０との境界）を狙って軸線Ｏと直交する方向からレーザを照射すれば、主体金具５０の溶融具合と外筒６５の溶融具合とをより均等な状態に近づけることができ、溶接部９９の形成による上記間隙の封止をより確実に行うことができる。もっとも、レーザの照射位置は上記突き合わせ位置よりも主体金具５０側に偏っていても、あるいは外筒６５側に偏っていても、レーザに溶融されて形成される溶接部９９が外筒６５と主体金具５０とに跨って形成されれば十分に、上記間隙の封止を行うことが可能である。   Further, when forming the welded portion 99 straddling between the rear end engaging portion 57 of the metal shell 50 and the front end 66 of the outer cylinder 65, the rear end engaging portion 57 of the metal shell 50 is contracted with the cylinder portion 571. If it is formed in a step shape having the diameter portion 572, the tip 66 of the outer cylinder 65 can be brought into contact with the cylinder portion 571 while being engaged with the reduced diameter portion 572. It is easy to perform positioning and temporary fixing of both at the time of joining. When joining the outer cylinder 65 and the metal shell 50 using, for example, laser welding, the tip 66 of the outer cylinder 65 is brought into contact with the cylinder portion 571 of the metal shell 50 as described above, and the abutting position (outer cylinder) If the laser is irradiated from the direction orthogonal to the axis O aiming at the boundary between the metal shell 50 and the metal shell 50, the melting state of the metal shell 50 and the melting state of the outer cylinder 65 can be brought closer to a more uniform state, The gap can be more reliably sealed by forming the weld 99. However, even if the laser irradiation position is biased toward the metal shell 50 side or the outer cylinder 65 side relative to the butting position, the welded portion 99 formed by being melted by the laser is formed with the outer cylinder 65 and the main body. If the gap is formed across the metal fitting 50, the gap can be sufficiently sealed.

そして、溶接部９９の径方向における厚みが外筒６５の厚みよりも厚くなるように溶接部９９を形成すれば、その溶接部９９が、外筒６５の先端側と径方向内側とのそれぞれにおいて主体金具５０との間にて形成されるので、溶接部９９の形成による上記間隙の封止をさらに確実に行うことができる。   And if the welding part 99 is formed so that the thickness in the radial direction of the welding part 99 may become thicker than the thickness of the outer cylinder 65, the welding part 99 will be in each of the front end side and radial direction inner side of the outer cylinder 65. Since it is formed between the metal shell 50, the gap can be more reliably sealed by forming the welded portion 99.

また、外筒６５の先端６６と主体金具５０の筒部５７１とに跨るように両者を外周側から加締めることで、主体金具５０に対し外筒６５の仮固定を行うことができ、溶接部９９を形成する過程で主体金具５０と外筒６５との位置ずれの発生を防止し、両者を跨ぐ溶接部９９を確実に形成することができる。   Further, the outer cylinder 65 can be temporarily fixed to the metal shell 50 by crimping both ends from the outer peripheral side so as to straddle the tip 66 of the outer cylinder 65 and the cylinder portion 571 of the metal shell 50, and the welded portion. In the process of forming 99, occurrence of misalignment between the metallic shell 50 and the outer cylinder 65 can be prevented, and the welded portion 99 straddling both can be reliably formed.

次に、本発明に係るガスセンサおよびその製造方法の第２の実施の形態について、図４，図５を参照して説明する。図４は、第２の実施の形態のガスセンサ１０１において、図１の円Ａの部分に相当し、主体金具１５０と外筒１６５とを接合した状態を示す部分断面拡大図である。図５は、第２の実施の形態のガスセンサ１０１の製造過程を示す図である。   Next, a second embodiment of the gas sensor and the manufacturing method thereof according to the present invention will be described with reference to FIGS. FIG. 4 is an enlarged partial cross-sectional view showing a state in which the metal shell 150 and the outer cylinder 165 are joined in the gas sensor 101 of the second embodiment, corresponding to the circle A in FIG. FIG. 5 is a diagram illustrating a manufacturing process of the gas sensor 101 according to the second embodiment.

なお、第２の実施の形態に係るガスセンサ１０１は、第１の実施の形態のガスセンサ１の主体金具５０と外筒６５との接合を異なる形態で行ったものである。従って、ここではガスセンサ１０１の主体金具１５０と外筒１６５との接合構造、およびガスセンサ１０１の製造過程における両者の接合方法について説明し、その他の部位の構成や製造方法については第１の実施の形態と同一であるので省略または簡略化するものとする。   The gas sensor 101 according to the second embodiment is obtained by joining the metal shell 50 and the outer cylinder 65 of the gas sensor 1 of the first embodiment in different forms. Therefore, here, the joining structure between the metal shell 150 of the gas sensor 101 and the outer cylinder 165 and the joining method in the manufacturing process of the gas sensor 101 will be described, and the configuration and manufacturing method of other parts will be described in the first embodiment. Since it is the same as the above, it will be omitted or simplified.

図４に示すように、第２の実施の形態のガスセンサ１０１の主体金具１５０は、第１の実施の形態の主体金具５０とは異なり、後端係合部１５７が段状に形成されていない。また、外筒１６５は、先端１６６の内周面１６８が後端係合部１５７の外周面１５８に係合可能となる内径に形成されると共に、外筒１６５の先端面１６９が、主体金具１５０の工具係合部１５２の後端面１５９に突き合わせ可能な長さに形成されている。   As shown in FIG. 4, the metal shell 150 of the gas sensor 101 of the second embodiment is different from the metal shell 50 of the first embodiment in that the rear end engaging portion 157 is not formed in a step shape. . Further, the outer cylinder 165 is formed to have an inner diameter that allows the inner peripheral surface 168 of the front end 166 to be engaged with the outer peripheral surface 158 of the rear end engaging portion 157, and the front end surface 169 of the outer cylinder 165 is formed of the metal shell 150. The tool engaging portion 152 has a length that can be abutted against the rear end surface 159.

図５に示すように、ガスセンサ１０１の製造過程では、第１の実施の形態と同様に、主体金具１５０にプロテクタ８や検出素子１０等（図１参照）を組み付けたガスセンサ１０１の先端側となる部位と、外筒１６５にセパレータ６０やグロメット７５等（図１参照）を組み付けたガスセンサ１０１の後端側となる部位とがそれぞれ組み立てられる。そして外筒配置工程では、その外筒１６５が、自身の内部に検出素子１０の電極部１２を含む後端側の部分を収容するように主体金具１５０の後端側から被せられる。このとき、図４に示すように、第２の実施の形態では、先端１６６の内周面１６８と後端係合部１５７の外周面１５８とが対向して配置されると共に、外筒１６５の先端面１６９（図４では溶接前の先端面１６９の位置が点線で示されている。）が主体金具１５０の工具係合部１５２の後端面１５９に対し突き合わされる。   As shown in FIG. 5, in the manufacturing process of the gas sensor 101, as in the first embodiment, the front end side of the gas sensor 101 in which the protector 8, the detection element 10, and the like (see FIG. 1) are assembled to the metal shell 150. The part and the part on the rear end side of the gas sensor 101 in which the separator 60, the grommet 75, etc. (see FIG. 1) are assembled to the outer cylinder 165 are assembled. In the outer cylinder arranging step, the outer cylinder 165 is covered from the rear end side of the metal shell 150 so as to accommodate the rear end side portion including the electrode portion 12 of the detection element 10 therein. At this time, as shown in FIG. 4, in the second embodiment, the inner peripheral surface 168 of the front end 166 and the outer peripheral surface 158 of the rear end engaging portion 157 are arranged to face each other, and The front end surface 169 (in FIG. 4, the position of the front end surface 169 before welding is indicated by a dotted line) is abutted against the rear end surface 159 of the tool engaging portion 152 of the metal shell 150.

次に溶接工程では、図５に示すように、外筒１６５の先端面１６９と工具係合部１５２の後端面１５９との突き合わせ位置（境界付近）を狙い、矢印Ｌで示すように、外筒１６５の周方向に一周にわたってレーザ溶接が行われる。このとき、外筒１６５の溶融具合と主体金具１５０の溶融具合とを略均等とするため、レーザは軸線Ｏ方向と直交する方向よりも後端側から照射される。これにより、外筒１６５の先端面１６９を含む先端１６６と主体金具１５０の工具係合部１５２とが溶融して一体となる。このレーザ照射は径方向全周にわたって行われ、主体金具１５０の工具係合部１５２と外筒１６５の先端１６６とに跨って溶接部１９９が形成されて、ガスセンサ１０１が完成する。上記のレーザの照射方向に応じ、形成された溶接部１９９の形状は、周方向の断面において、径方向内側に向かうにつれて軸線Ｏ方向の先端側に延びる形状をなす。   Next, in the welding process, as shown in FIG. 5, the abutting position (near the boundary) between the front end surface 169 of the outer tube 165 and the rear end surface 159 of the tool engaging portion 152 is aimed, and the outer tube is Laser welding is performed over the circumference of 165 in the circumferential direction. At this time, in order to make the melting condition of the outer cylinder 165 and the melting condition of the metal shell 150 substantially equal, the laser is irradiated from the rear end side rather than the direction orthogonal to the axis O direction. Thereby, the front end 166 including the front end surface 169 of the outer cylinder 165 and the tool engaging portion 152 of the metal shell 150 are melted and integrated. This laser irradiation is performed over the entire circumference in the radial direction, and a welded portion 199 is formed across the tool engaging portion 152 of the metal shell 150 and the tip 166 of the outer cylinder 165, and the gas sensor 101 is completed. In accordance with the laser irradiation direction, the formed welded portion 199 has a shape extending toward the tip end side in the axis O direction as it goes radially inward in the circumferential cross section.

なお、図４に示すように、この溶接部１９９の外表面は、メニスカス状に凹んだ曲面形状に形成されることが望ましく、このようにすれば、外筒１６５の先端１６６と主体金具１５０との間の間隙への入口部分を溶接部１９９で封止する厚みを有することができ、間隙の封止をより確実に行うことができる。また、レーザ溶接時に出力を調整し、形成後の溶接部１９９の径方向（図中紙面左右方向）における厚み（図４において矢印Ｃで示す大きさ）が、少なくとも外筒１６５の厚み（図４において矢印Ｄで示す大きさ）よりも大きくなるようにすれば、主体金具１５０と外筒１６５との接合強度を高められ望ましいことは、第１の実施の形態と同様である。   As shown in FIG. 4, the outer surface of the welded portion 199 is preferably formed in a curved shape that is recessed in a meniscus shape, and in this way, the tip 166 of the outer tube 165, the metal shell 150, It is possible to have a thickness that seals the entrance portion to the gap between the welded portions 199, so that the gap can be more reliably sealed. Further, the output is adjusted during laser welding, and the thickness (the size indicated by the arrow C in FIG. 4) in the radial direction (left and right direction in the drawing) of the welded portion 199 after formation is at least the thickness of the outer cylinder 165 (FIG. 4). In the same manner as in the first embodiment, it is desirable to increase the bonding strength between the metal shell 150 and the outer cylinder 165 if the size is larger than the size indicated by the arrow D in FIG.

このように作製される第２の実施の形態のガスセンサ１０１においても、外筒１６５の先端１６６から主体金具１５０の工具係合部１５２にかけての部位に両者を跨ぐ溶接部１９９が形成されたことにより、主体金具１５０の後端係合部１５７の外周面１５８と、外筒１６５の先端１６６の内周面１６８との間隙が外気と遮断された状態に密封される。従ってガスセンサ１０１の使用の際に、ガスセンサ１０１が被水しても、溶接部１９９によって、後端係合部１５７の外周面１５８と先端１６６の内周面１６８との間の間隙に水滴等が浸入することがない。つまり、先端１６６の内周面１６８と後端係合部１５７の外周面１５８との間の間隙への入口部分となり得る外筒１６５の先端面１６９と工具係合部１５２の後端面１５９との間の間隙が、溶接部１９９の形成によって封止されるので、溶接部１９９と主体金具１５０との界面に長期間水滴等が接触した場合に生じやすい腐食の発生を防止することができる。なお、工具係合部１５２の後端面１５９において露出された溶接部１９９と工具係合部１５２との間の界面は、第１の実施の形態と同様に、狭い間隙に水滴等が入り込んだ場合とは異なり広い面積をもって外気に接触した状態となるため、水滴等が揮発されやすく、上記のような腐食を生じにくい。   Also in the gas sensor 101 according to the second embodiment manufactured in this way, a welded portion 199 is formed across a portion from the tip 166 of the outer cylinder 165 to the tool engaging portion 152 of the metal shell 150. The gap between the outer peripheral surface 158 of the rear end engaging portion 157 of the metal shell 150 and the inner peripheral surface 168 of the front end 166 of the outer cylinder 165 is sealed in a state where it is blocked from outside air. Therefore, when the gas sensor 101 is used, even if the gas sensor 101 is flooded, the welded portion 199 causes water droplets or the like in the gap between the outer peripheral surface 158 of the rear end engaging portion 157 and the inner peripheral surface 168 of the front end 166. There is no infiltration. That is, the front end surface 169 of the outer cylinder 165 and the rear end surface 159 of the tool engaging portion 152 that can be an entrance portion into the gap between the inner peripheral surface 168 of the front end 166 and the outer peripheral surface 158 of the rear end engaging portion 157. Since the gap between them is sealed by the formation of the welded portion 199, it is possible to prevent the occurrence of corrosion that tends to occur when water droplets or the like contact the interface between the welded portion 199 and the metal shell 150 for a long period of time. Note that the interface between the welded portion 199 and the tool engaging portion 152 exposed on the rear end surface 159 of the tool engaging portion 152 is a case where water droplets or the like enter a narrow gap as in the first embodiment. Unlike water, it is in a state of being in contact with the outside air with a large area, so that water droplets and the like are easily volatilized, and the above-described corrosion hardly occurs.

次に、本発明に係るガスセンサおよびその製造方法の第３の実施の形態について、図６，図７を参照して説明する。図６は、第３の実施の形態のガスセンサ２０１において、図１の円Ａの部分に相当し、主体金具１５０と外筒２６５とを接合した状態を示す部分断面拡大図である。図７は、第３の実施の形態のガスセンサ２０１の製造過程を示す図である。   Next, a third embodiment of the gas sensor and the manufacturing method thereof according to the present invention will be described with reference to FIGS. FIG. 6 is a partial cross-sectional enlarged view showing a state in which the metal shell 150 and the outer cylinder 265 are joined in the gas sensor 201 of the third embodiment, corresponding to the circle A in FIG. FIG. 7 is a diagram illustrating a manufacturing process of the gas sensor 201 according to the third embodiment.

第３の実施の形態に係るガスセンサ２０１は、第２の実施の形態で用いた主体金具１５０に対し外筒２６５を接合するものであり、その接合の形態を第１，第２の実施の形態とは異なる形態にて行ったものである。従って、ここではガスセンサ２０１の外筒２６５を主体金具１５０に接合するための構造、およびガスセンサ２０１の製造過程における両者の接合方法について説明し、その他の部位の構成や製造方法については第１および第２の実施の形態と同一であるので省略または簡略化するものとする。   The gas sensor 201 according to the third embodiment joins the outer cylinder 265 to the metal shell 150 used in the second embodiment, and the joining form is the first and second embodiments. This was done in a different form. Therefore, here, a structure for joining the outer cylinder 265 of the gas sensor 201 to the metal shell 150 and a joining method of both in the manufacturing process of the gas sensor 201 will be described. Since this embodiment is the same as the second embodiment, it will be omitted or simplified.

図６に示すように、第３の実施の形態のガスセンサ２０１の外筒２６５は、第２の実施の形態の外筒１６５と略同等の内径を有しつつも軸線Ｏ方向に短く形成されている。このため、ガスセンサ２０１では、外筒２６５の先端２６６が主体金具１５０の工具係合部１５２に対し離間した状態で、外筒２６５と主体金具１５０とが接合されている。   As shown in FIG. 6, the outer cylinder 265 of the gas sensor 201 of the third embodiment is formed to be short in the direction of the axis O while having an inner diameter substantially equal to that of the outer cylinder 165 of the second embodiment. Yes. For this reason, in the gas sensor 201, the outer cylinder 265 and the metal shell 150 are joined with the tip 266 of the outer cylinder 265 being separated from the tool engaging portion 152 of the metal shell 150.

図７に示すように、ガスセンサ２０１の製造過程では、第２の実施の形態と同様に、主体金具１５０にプロテクタ８や検出素子１０等（図１参照）を組み付けたガスセンサ２０１の先端側となる部位と、外筒２６５にセパレータ６０やグロメット７５等（図１参照）を組み付けたガスセンサ２０１の後端側となる部位がそれぞれ組み立てられる。そして外筒配置工程では、その外筒２６５が、自身の内部に検出素子１０の電極部１２を含む後端側の部分を収容するように主体金具１５０の後端側から被せられる。このとき、図６に示すように、第３の実施の形態では、先端２６６の内周面２６８と後端係合部１５７の外周面１５８とが対向して配置されると共に、外筒２６５の先端面２６９（図６では溶接前の先端面２６９の位置が点線で示されている。）が、主体金具１５０の工具係合部１５２の後端面１５９に対し、離間した状態で配置される。   As shown in FIG. 7, in the manufacturing process of the gas sensor 201, as in the second embodiment, the front end side of the gas sensor 201 in which the protector 8, the detection element 10, and the like (see FIG. 1) are assembled to the metal shell 150. The part and the part on the rear end side of the gas sensor 201 in which the separator 60, the grommet 75, etc. (see FIG. 1) are assembled to the outer cylinder 265 are assembled. Then, in the outer cylinder placement step, the outer cylinder 265 is covered from the rear end side of the metal shell 150 so as to accommodate the rear end side portion including the electrode portion 12 of the detection element 10 therein. At this time, as shown in FIG. 6, in the third embodiment, the inner peripheral surface 268 of the front end 266 and the outer peripheral surface 158 of the rear end engaging portion 157 are arranged to face each other, and The front end surface 269 (in FIG. 6, the position of the front end surface 269 before welding is indicated by a dotted line) is arranged in a state of being separated from the rear end surface 159 of the tool engaging portion 152 of the metal shell 150.

次に溶接工程では、図７に示すように、外筒２６５の先端面２６９と、主体金具１５０の後端係合部１５７の外周面１５８との突き合わせ位置（境界付近）を狙い、矢印Ｌで示すように、外筒２６５の周方向に一周にわたってレーザ溶接が行われる。このとき、外筒２６５の溶融具合と主体金具１５０の溶融具合とを略均等とするため、レーザは軸線Ｏ方向と直交する方向よりも先端側から照射される。これにより、外筒２６５の先端面２６９を含む先端２６６と主体金具１５０の後端係合部１５７とが溶融して一体となる。このレーザ照射は径方向全周にわたって行われ、主体金具１５０の後端係合部１５７と外筒２６５の先端２６６との間にて両者を跨ぐ溶接部２９９が形成されて、ガスセンサ２０１が完成する。上記のレーザの照射方向に応じ、形成された溶接部２９９の形状は、周方向の断面において、径方向内側に向かうにつれて軸線Ｏ方向の後端側に延びる形状をなす。   Next, in the welding process, as shown in FIG. 7, aiming at the abutting position (near the boundary) between the front end surface 269 of the outer cylinder 265 and the outer peripheral surface 158 of the rear end engaging portion 157 of the metal shell 150, As shown, laser welding is performed over the entire circumference of the outer cylinder 265. At this time, in order to make the melting condition of the outer cylinder 265 and the melting condition of the metal shell 150 substantially equal, the laser is irradiated from the tip side rather than the direction orthogonal to the axis O direction. Thereby, the front end 266 including the front end surface 269 of the outer cylinder 265 and the rear end engaging portion 157 of the metal shell 150 are melted and integrated. This laser irradiation is performed over the entire circumference in the radial direction, and a welded part 299 is formed between the rear end engaging part 157 of the metal shell 150 and the front end 266 of the outer cylinder 265 to complete the gas sensor 201. . According to the laser irradiation direction, the formed welded portion 299 has a shape extending toward the rear end side in the axis O direction as it goes radially inward in the circumferential cross section.

なお、図６に示すように、この溶接部２９９の外表面は、メニスカス状に凹んだ曲面形状に形成されることが望ましく、このようにすれば、外筒２６５の先端２６６と主体金具１５０との間の間隙への入口部分を溶接部２９９で封止する厚みを有することができ、間隙の封止をより確実に行うことができる。また、レーザ溶接時に出力を調整し、形成後の溶接部２９９の径方向（図中紙面左右方向）における厚み（図６おいて矢印Ｃで示す大きさ）が、少なくとも外筒２６５の厚み（図６において矢印Ｄで示す大きさ）よりも大きくなるようにすれば、主体金具１５０と外筒２６５との接合強度を高められ望ましいことは、第１，第２の実施の形態と同様である。   As shown in FIG. 6, it is desirable that the outer surface of the welded portion 299 be formed in a curved shape that is recessed in a meniscus shape. In this way, the tip 266 of the outer cylinder 265, the metal shell 150, It is possible to have a thickness that seals the entrance portion to the gap between the welded portions 299, so that the gap can be more reliably sealed. Further, the output is adjusted at the time of laser welding, and the thickness (the size indicated by the arrow C in FIG. 6) in the radial direction (left and right direction in the drawing) of the welded portion 299 after formation is at least the thickness of the outer cylinder 265 (see FIG. 6). As in the first and second embodiments, it is desirable to increase the bonding strength between the metal shell 150 and the outer cylinder 265 if it is larger than the size indicated by the arrow D in FIG.

このように作製される第３の実施の形態のガスセンサ２０１においても、外筒２６５の先端２６６から主体金具１５０の後端係合部１５７にかけての部位にて両者を跨ぐ溶接部２９９が形成されたことにより、主体金具１５０の後端係合部１５７の外周面１５８と、外筒２６５の先端２６６の内周面２６８とで構成される間隙が外気と遮断された状態に密封される。従ってガスセンサ２０１の使用の際に、ガスセンサ２０１が被水しても、溶接部２９９によって、後端係合部１５７の外周面１５８と先端２６６の内周面２６８との間の間隙に水滴等が浸入することがない。つまり、接合前の状態において、先端２６６の内周面２６８と後端係合部１５７の外周面１５８との間の間隙への入口部分となり得る外筒２６５の先端面２６９と工具係合部１５２の後端係合部１５７の外周面１５８との間の間隙が、溶接部２９９の形成によって封止されるので、溶接部２９９と主体金具１５０との界面に長期間水滴等が接触した場合に生じやすい腐食の発生を防止することができる。なお、後端係合部１５７の外周面１５８において外方に露出された溶接部２９９と後端係合部１５７との間の界面は、第１，第２の実施の形態と同様に、狭い間隙に水滴等が入り込んだ場合とは異なり広い面積をもって外気に接触した状態となるため、水滴等が揮発されやすく、上記のような腐食を生じにくい。   Also in the gas sensor 201 of the third embodiment manufactured in this way, the welded portion 299 is formed across the both ends at the portion from the front end 266 of the outer cylinder 265 to the rear end engaging portion 157 of the metal shell 150. Thus, the gap formed by the outer peripheral surface 158 of the rear end engaging portion 157 of the metal shell 150 and the inner peripheral surface 268 of the front end 266 of the outer cylinder 265 is sealed in a state where it is blocked from the outside air. Therefore, when the gas sensor 201 is used, even if the gas sensor 201 is submerged, the welded portion 299 causes water droplets or the like in the gap between the outer peripheral surface 158 of the rear end engaging portion 157 and the inner peripheral surface 268 of the front end 266. There is no infiltration. That is, in the state before joining, the front end surface 269 of the outer cylinder 265 and the tool engaging portion 152 that can be an entrance portion to the gap between the inner peripheral surface 268 of the front end 266 and the outer peripheral surface 158 of the rear end engaging portion 157. Since the gap between the rear end engaging portion 157 and the outer peripheral surface 158 is sealed by the formation of the welded portion 299, when a water droplet or the like is in contact with the interface between the welded portion 299 and the metal shell 150 for a long period of time. It is possible to prevent the occurrence of corrosion that tends to occur. Note that the interface between the welded portion 299 exposed outwardly on the outer peripheral surface 158 of the rear end engaging portion 157 and the rear end engaging portion 157 is narrow, as in the first and second embodiments. Unlike the case where water droplets or the like enter the gap, the water contact with the outside air has a wide area, so that the water droplets or the like are easily volatilized, and the above-described corrosion hardly occurs.

なお、本発明は上記各実施の形態に限られず、各種の変形が可能である。例えば、第１の実施の形態において、主体金具５０の後端係合部５７と工具係合部５２とは連続していなくともよく、例えば、加締め部５３の加締めの際に変形し、加締められた状態が維持されるように、加締め部５３にかかる反発力を分散させるため加締め時に変形させる部位などを設けてもよい。第２，第３の実施の形態についても同様である。   The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, in the first embodiment, the rear end engaging portion 57 and the tool engaging portion 52 of the metal shell 50 do not have to be continuous, for example, deformed when the caulking portion 53 is caulked, In order to disperse the repulsive force applied to the caulking portion 53 so as to maintain the crimped state, a portion that is deformed at the time of caulking may be provided. The same applies to the second and third embodiments.

また、第１の実施の形態では、外筒６５の先端面６９と、主体金具５０の後端係合部５７の筒部５７１と縮径部５７２との後端向き面５７４とを突き合わせた状態で加締め、レーザ溶接を行ったが、このとき、先端面６９と、筒部５７１および縮径部５７２の後端向き面５７４とは、互いに当接していてもよいし、あるいは両者間に間隙を有する状態であってもよい。また、レーザの照射位置については、外筒６５の先端面６９と、主体金具５０の後端係合部５７の筒部５７１と縮径部５７２との後端向き面５７４との突き合わせ位置（つまり主体金具５０と外筒６５の境界付近）を狙うことが好ましい。もっとも、外筒６５側に偏ってレーザを照射し、溶融した部分（溶接部９９）によって外筒６５と主体金具５０とが接続されてもよいし、主体金具５０側に偏ってレーザを照射し、溶融した部分により形成される溶接部９９を介し、両者が接合されるようにしてもよい。つまりレーザ溶接によって、溶接部９９が、軸線Ｏ方向において、外筒６５の先端６６と、主体金具５０の筒部５７１とを跨いで形成されて両者を接合すると共に、外筒６５の先端６６の内周面６８と主体金具５０の縮径部５７２の外周面５７３との間の間隙が、この溶接部９９によって封止された形態となれば足りる。   In the first embodiment, the front end surface 69 of the outer cylinder 65 is in contact with the rear end facing surface 574 of the cylindrical portion 571 and the reduced diameter portion 572 of the rear end engaging portion 57 of the metal shell 50. At this time, the front end surface 69 and the cylindrical portion 571 and the rear end facing surface 574 may be in contact with each other, or there may be a gap between them. It may be in a state having As for the laser irradiation position, the abutting position between the front end surface 69 of the outer cylinder 65 and the rear end facing surface 574 of the cylindrical portion 571 and the reduced diameter portion 572 of the rear end engaging portion 57 of the metal shell 50 (that is, It is preferable to aim at the vicinity of the boundary between the metal shell 50 and the outer cylinder 65. However, the outer cylinder 65 may be biased to irradiate the laser, and the outer cylinder 65 and the metallic shell 50 may be connected by the melted portion (welded portion 99), or the metallic shell 50 may be biased to irradiate the laser. Alternatively, both may be joined via a weld 99 formed by the melted portion. That is, by laser welding, the weld 99 is formed across the tip 66 of the outer tube 65 and the tube 571 of the metal shell 50 in the direction of the axis O, and joins them together. It suffices if the gap between the inner peripheral surface 68 and the outer peripheral surface 573 of the reduced diameter portion 572 of the metal shell 50 is sealed by the welded portion 99.

また、第２，第３の実施の形態においても、第１の実施の形態と同様に、外筒１６５，２６５の先端１６６，２６６を主体金具１５０に対して加締めてもよい。あるいは第１の実施の形態において、主体金具５０と外筒６５との加締めを行わず、外筒６５の先端６６が後端係合部５７に係合した際に容易に外れたりしないように、外筒６５の内径を後端係合部５７の縮径部５７２の外径との径差を揃えてもよい。   Also in the second and third embodiments, the tips 166 and 266 of the outer cylinders 165 and 265 may be crimped to the metal shell 150 as in the first embodiment. Alternatively, in the first embodiment, the metal shell 50 and the outer cylinder 65 are not swaged so that the front end 66 of the outer cylinder 65 is not easily detached when engaged with the rear end engaging portion 57. The diameter difference between the inner diameter of the outer cylinder 65 and the outer diameter of the reduced diameter portion 572 of the rear end engaging portion 57 may be made uniform.

また、第２の実施の形態において、例えば図８に示す、ガスセンサ３０１のように、外筒３６５の先端３６６に径方向外側へ拡径する拡径部３３０を有してもよい。この場合、外筒３６５の先端３６６の内周面３６８は、その内径を、第２の実施の形態と同様に後端係合部１５７の外周面１５８に係合可能な大きさに形成する。拡径部３３０は、軸線Ｏ方向（図中紙面上下方向）の先端向きの面である軸方向先端面３３１を、主体金具１５０の工具係合部１５２の後端面１５９に突き合わせ、径方向（図中紙面左右方向）の先端向きの面である径方向先端面３６９は、その位置が、工具係合部１５２の後端面１５９上に配置されるようにする。すると、拡径部３３０の径方向先端面３６９と工具係合部１５２の後端面１５９とは突き合わせ位置（境界付近）を基準に径方向外側に向かうにつれ軸線方向後端側へ広がる配置関係となる。その突き合わせ位置へ向けてレーザを照射すれば、外筒３６５と主体金具１５０とをより均等に跨ぐように溶接部３９９を形成することができ、この突き合わせ位置を入口とする外筒３６５の先端３６６の内周面３６８と主体金具１５０の後端係合部１５７の外周面１５８との間隙の封止を確実に行うことができる。さらに、レーザ溶接による溶接部３９９の形成前に、拡径部３３０の軸方向先端面３３１と工具係合部１５２の後端面１５９とを抵抗溶接により接合してもよい。このようにすれば、拡径部３３０の軸方向先端面３３１と工具係合部１５２の後端面１５９との間の間隙を確実に封止でき、先端３６６の内周面３６８と後端係合部１５７の外周面１５８との間隙への水滴等の浸入を完全に防止できる。また、レーザ溶接の際に、拡径部３３０の径方向先端面３６９を、工具係合部１５２の後端面１５９に対し位置決めした上で固定できるので、レーザ溶接を容易に行える。なお、レーザ溶接の際に、拡径部３３０の径方向先端面３６９と工具係合部１５２の後端面１５９との突き合わせ位置を確実に溶融するのであれば、軸線Ｏ方向に沿ってレーザを照射して溶接部３９９を形成してもよい。   In the second embodiment, for example, a gas sensor 301 shown in FIG. 8 may have a diameter increasing portion 330 that expands radially outward at the tip 366 of the outer cylinder 365. In this case, the inner peripheral surface 368 of the front end 366 of the outer cylinder 365 is formed so that the inner diameter thereof can be engaged with the outer peripheral surface 158 of the rear end engaging portion 157 as in the second embodiment. The enlarged diameter portion 330 abuts the axial front end surface 331, which is the surface facing the front end in the direction of the axis O (the vertical direction in the drawing), with the rear end surface 159 of the tool engaging portion 152 of the metal shell 150, and the radial direction (see FIG. The position of the radial front end surface 369 that is the surface facing the front end in the left-right direction of the middle paper surface is arranged on the rear end surface 159 of the tool engaging portion 152. Then, the radial front end surface 369 of the diameter-enlarged portion 330 and the rear end surface 159 of the tool engaging portion 152 are arranged so as to expand toward the rear end side in the axial direction as they go radially outward with respect to the abutting position (near the boundary). . By irradiating the laser toward the abutting position, the welded portion 399 can be formed so as to straddle the outer cylinder 365 and the metal shell 150 more evenly, and the distal end 366 of the outer cylinder 365 having the abutting position as an entrance. The gap between the inner peripheral surface 368 and the outer peripheral surface 158 of the rear end engaging portion 157 of the metal shell 150 can be reliably sealed. Further, the axial front end surface 331 of the enlarged diameter portion 330 and the rear end surface 159 of the tool engaging portion 152 may be joined by resistance welding before the formation of the welded portion 399 by laser welding. In this way, the gap between the axial front end surface 331 of the enlarged diameter portion 330 and the rear end surface 159 of the tool engaging portion 152 can be reliably sealed, and the inner peripheral surface 368 of the front end 366 and the rear end engagement can be reliably sealed. Intrusion of water droplets or the like into the gap between the outer peripheral surface 158 of the portion 157 can be completely prevented. Moreover, since the radial front end surface 369 of the enlarged diameter portion 330 can be positioned and fixed with respect to the rear end surface 159 of the tool engaging portion 152 during laser welding, laser welding can be easily performed. In laser welding, if the abutting position between the radial front end surface 369 of the enlarged diameter portion 330 and the rear end surface 159 of the tool engaging portion 152 is reliably melted, the laser is irradiated along the axis O direction. Then, the welded portion 399 may be formed.

また、本発明に係る主体金具と外筒との接合方法を用い、主体金具とプロテクタとの接合を行ってもよい。もっとも、主体金具の雄ねじ部より先端側に取り付けられるプロテクタは、ガスセンサが自動車の排気管に取り付けられた際に排気管内に露出される部分であり、排気管外に露出される外筒とは異なり高温の排気ガス（例えば８００℃）に晒される。このため、プロテクタと主体金具との間隙に水滴等が浸入しても比較的揮発されやすいので、本発明を主体金具と外筒との接合に適用することは、接合部分の腐食を防止する上でより高い効果を奏するものである。   Moreover, you may join a metal shell and a protector using the joining method of the metal shell and an outer cylinder which concern on this invention. However, the protector that is attached to the front end side of the male thread of the metal shell is the part that is exposed inside the exhaust pipe when the gas sensor is attached to the exhaust pipe of an automobile, and is different from the outer cylinder that is exposed outside the exhaust pipe. Exposure to high temperature exhaust gas (eg 800 ° C.). For this reason, even if water droplets or the like enter the gap between the protector and the metal shell, it is relatively easy to volatilize. Therefore, applying the present invention to the joining between the metal shell and the outer cylinder prevents corrosion of the joint portion. It has a higher effect.

酸素センサ、ＮＯｘセンサ、ＨＣセンサなどのガスセンサおよびその製造方法に適用し得る。   The present invention can be applied to gas sensors such as oxygen sensors, NOx sensors, HC sensors, and manufacturing methods thereof.

ガスセンサ１の縦断面図である。1 is a longitudinal sectional view of a gas sensor 1. FIG. 図１の円Ａの部分を拡大してみたガスセンサ１の断面図である。It is sectional drawing of the gas sensor 1 which expanded the part of the circle | round | yen A of FIG. ガスセンサ１の製造過程を示す図である。FIG. 3 is a diagram showing a manufacturing process of the gas sensor 1. 第２の実施の形態のガスセンサ１０１において、図１の円Ａの部分に相当し、主体金具１５０と外筒１６５とを接合した状態を示す部分断面拡大図である。In the gas sensor 101 of 2nd Embodiment, it is corresponded to the part of the circle | round | yen A of FIG. 1, and it is a fragmentary sectional enlarged view which shows the state which joined the metal shell 150 and the outer cylinder 165. FIG. 第２の実施の形態のガスセンサ１０１の製造過程を示す図である。It is a figure which shows the manufacture process of the gas sensor 101 of 2nd Embodiment. 第３の実施の形態のガスセンサ２０１において、図１の円Ａの部分に相当し、主体金具１５０と外筒２６５とを接合した状態を示す部分断面拡大図である。In the gas sensor 201 of 3rd Embodiment, it is equivalent to the part of the circle | round | yen A of FIG. 1, and it is a fragmentary sectional enlarged view which shows the state which joined the metal shell 150 and the outer cylinder 265. FIG. 第３の実施の形態のガスセンサ２０１の製造過程を示す図である。It is a figure which shows the manufacture process of the gas sensor 201 of 3rd Embodiment. 変形例としてのガスセンサ３０１において、図１の円Ａの部分に相当し、主体金具１５０と外筒３６５とを接合した状態を示す部分断面拡大図である。In the gas sensor 301 as a modified example, it corresponds to the portion of the circle A in FIG.

符号の説明Explanation of symbols

１ ガスセンサ
１０ 検出素子
１１ 先端部
５０ 主体金具
５２ 工具係合部
５７ 後端係合部
６５ 外筒
６６ 先端
６７ 加締め部
９９ 溶接部
５７１ 筒部
５７２ 縮径部 DESCRIPTION OF SYMBOLS 1 Gas sensor 10 Detection element 11 Front-end | tip part 50 Metal fitting 52 Tool engaging part 57 Rear-end engaging part 65 Outer cylinder 66 Front end 67 Clamping part 99 Welding part 571 Cylindrical part 572 Reduced diameter part

Claims (19)

軸線方向に延びると共に、自身の先端側に被検出ガスを検出するための検出部を有する検出素子と、
前記検出部を自身の先端から突出させつつ、前記検出素子の径方向周囲を取り囲む主体金具と、
当該主体金具に固定され、前記検出素子の後端側の径方向周囲を取り囲む筒状の外筒と
を有するガスセンサにおいて、
前記主体金具は、径方向に拡径された鍔部と、当該鍔部の後端側に形成される後端部とを有し、
前記外筒の先端が前記主体金具の前記後端部の少なくとも一部の径方向周囲を取り囲むように配置され、かつ、前記外筒の前記先端と前記主体金具とに跨って形成された溶接部が全周にわたって形成されていることを特徴とするガスセンサ。 A detection element that extends in the axial direction and has a detection unit for detecting a gas to be detected on its tip side;
A metal shell that surrounds the periphery of the detection element in the radial direction while causing the detection unit to protrude from its tip,
A gas sensor having a cylindrical outer cylinder fixed to the metal shell and surrounding a radial periphery on the rear end side of the detection element,
The metal shell has a flange portion radially expanded in diameter, and a rear end portion formed on the rear end side of the flange portion,
A welded portion that is disposed so that the front end of the outer cylinder surrounds at least a portion of the rear end portion of the metal shell in the radial direction and straddles the front end of the outer tube and the metal shell. Is formed over the entire circumference. 前記主体金具の前記後端部は、筒部と、当該筒部の後端側に接続し、その筒部よりも縮径する縮径部とを有し、
前記外筒の前記先端は、前記縮径部の径方向周囲を取り囲むように配置され、
前記溶接部は、前記外筒の前記先端と前記筒部との間に跨って形成されていることを特徴とする請求項１に記載のガスセンサ。 The rear end portion of the metal shell has a cylindrical portion and a reduced diameter portion that is connected to the rear end side of the cylindrical portion and has a diameter smaller than that of the cylindrical portion,
The distal end of the outer cylinder is disposed so as to surround the circumference of the reduced diameter portion in the radial direction,
The gas sensor according to claim 1, wherein the welded portion is formed between the tip of the outer cylinder and the cylinder portion. 前記溶接部は、径方向における自身の厚みが、前記外筒の厚みよりも厚く形成されていることを特徴とする請求項２に記載のガスセンサ。   The gas sensor according to claim 2, wherein the welded portion is formed such that a thickness of the welded portion in a radial direction is larger than a thickness of the outer cylinder. 前記溶接部は、径方向における自身の厚みが、前記外筒の厚みよりも２倍以上厚く形成されていることを特徴とする請求項３に記載のガスセンサ。   4. The gas sensor according to claim 3, wherein the welded portion is formed such that a thickness of the welded portion in the radial direction is twice or more thicker than a thickness of the outer cylinder. 前記溶接部の先端と前記鍔部の後端との距離が１ｍｍ以上であることを特徴とする請求項１乃至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 a distance between a front end of the welded portion and a rear end of the flange portion is 1 mm or more. 前記外筒の前記先端と前記主体金具の前記筒部とに跨がるように、両者を外周側から加締めた加締め部が形成されていることを特徴とする請求項２乃至５のいずれかに記載のガスセンサ。   6. A caulking part is formed by caulking both from the outer peripheral side so as to straddle the tip of the outer cylinder and the cylinder part of the metallic shell. The gas sensor according to Crab. 前記溶接部は、前記外筒の前記先端と前記主体金具の前記鍔部との間に跨って形成されていることを特徴とする請求項１に記載のガスセンサ。   The gas sensor according to claim 1, wherein the welded portion is formed between the tip of the outer cylinder and the flange portion of the metal shell. 前記外筒は、自身の前記先端に、径方向外側に拡径する拡径部を有し、
前記溶接部は、前記拡径部と前記鍔部との間に跨って形成されていることを特徴とする請求項７に記載のガスセンサ。 The outer cylinder has a diameter-expanding portion that expands radially outward at the tip thereof.
The gas sensor according to claim 7, wherein the welded portion is formed between the enlarged diameter portion and the flange portion. 前記溶接部は、径方向内側に向かうにつれて、前記軸線方向の先端側に延びて形成されていることを特徴とする請求項７または８に記載のガスセンサ。   9. The gas sensor according to claim 7, wherein the welded portion is formed to extend toward the tip end side in the axial direction as it goes radially inward. 前記外筒の前記先端は、前記主体金具の前記鍔部とは離間しつつ前記後端部の径方向周囲を取り囲むように配置され、
前記溶接部は、前記外筒の前記先端と前記主体金具の前記後端部との間に跨って形成されていることを特徴とする請求項１に記載のガスセンサ。 The front end of the outer cylinder is disposed so as to surround the radial periphery of the rear end portion while being separated from the flange portion of the metal shell,
2. The gas sensor according to claim 1, wherein the welded portion is formed between the front end of the outer cylinder and the rear end portion of the metal shell. 前記溶接部は、径方向内側に向かうにつれて、前記軸線方向の後端側に延びて形成されていることを特徴とする請求項１０に記載のガスセンサ。   The gas sensor according to claim 10, wherein the welded portion is formed to extend toward the rear end side in the axial direction as it goes radially inward. 前記溶接部は、径方向における自身の厚みが、前記外筒の厚みよりも厚く形成されていることを特徴とする請求項７乃至１１のいずれかに記載のガスセンサ。   The gas sensor according to any one of claims 7 to 11, wherein the welded portion is formed such that its thickness in a radial direction is larger than a thickness of the outer cylinder. 前記溶接部は、その外表面が凹んだ曲面形状に形成されることを特徴とする請求項７乃至１２のいずれかに記載のガスセンサ。   The gas sensor according to any one of claims 7 to 12, wherein the welded portion is formed in a curved surface shape whose outer surface is recessed. 軸線方向に延びると共に、自身の先端側に被検出ガスを検出するための検出部を有する検出素子と、
前記検出部を自身の先端から突出させつつ、前記検出素子の径方向周囲を取り囲む主体金具と、
当該主体金具に固定され、前記検出素子の後端側の径方向周囲を取り囲む筒状の外筒と
を有するガスセンサの製造方法において、
前記主体金具は、径方向に拡径された鍔部と、当該鍔部よりも後端側に形成される筒部と、当該筒部の後端側に接続し、その筒部よりも縮径する縮径部とを有し、
前記外筒の前記先端を、前記縮径部の径方向周囲を取り囲むように配置させつつ、前記筒部の後端向き面に当接させる外筒配置工程と、
前記外筒の前記先端と前記主体金具の前記筒部との境界付近に向けて全周にわたってレーザ溶接を行い、前記外筒の前記先端と前記主体金具の前記筒部との間に跨って溶接部を形成する溶接工程と
を有することを特徴とするガスセンサの製造方法。 A detection element that extends in the axial direction and has a detection unit for detecting a gas to be detected on its tip side;
A metal shell that surrounds the periphery of the detection element in the radial direction while causing the detection unit to protrude from its tip,
A gas sensor manufacturing method comprising: a cylindrical outer cylinder fixed to the metal shell and surrounding a radial direction of the rear end side of the detection element;
The metallic shell is connected to the rear end side of the tubular portion formed on the rear end side of the collar portion, the tubular portion formed on the rear end side of the collar portion, and has a diameter smaller than that of the cylindrical portion. Having a reduced diameter portion,
An outer cylinder placement step of bringing the tip of the outer cylinder into contact with the rear end-facing surface of the cylinder part while arranging the circumference of the reduced diameter part to surround the radial direction;
Laser welding is performed over the entire circumference toward the vicinity of the boundary between the tip of the outer cylinder and the cylinder portion of the metal shell, and welding is performed between the tip of the outer cylinder and the cylinder portion of the metal shell. And a welding process for forming the portion. 前記溶接工程では、前記溶接部の径方向における厚みが前記外筒の厚みよりも厚く形成されるように、前記外筒の前記先端と前記主体金具の前記筒部との境界付近に向けて全周にわたってレーザ溶接を行うことを特徴とする請求項１４に記載のガスセンサの製造方法。   In the welding step, the entire thickness of the welded portion is increased toward the boundary between the tip of the outer tube and the cylindrical portion of the metal shell so that the thickness in the radial direction of the welded portion is greater than the thickness of the outer tube. The method of manufacturing a gas sensor according to claim 14, wherein laser welding is performed over a circumference. 前記外筒配置工程後で前記溶接工程前に、前記外筒の前記先端と前記主体金具の前記筒部とに跨がるように、両者を外周側から加締めて加締め部を形成する加締め工程を有することを特徴とする請求項１４または１５に記載のガスセンサの製造方法。   After the outer cylinder placement step and before the welding step, a caulking portion is formed by caulking both from the outer peripheral side so as to straddle the tip of the outer cylinder and the cylinder portion of the metal shell. The gas sensor manufacturing method according to claim 14, further comprising a fastening step. 軸線方向に延びると共に、自身の先端側に被検出ガスを検出するための検出部を有する検出素子と、
前記検出部を自身の先端から突出させつつ、前記検出素子の径方向周囲を取り囲む主体金具と、
当該主体金具に固定され、前記検出素子の後端側の径方向周囲を取り囲む筒状の外筒と
を有するガスセンサの製造方法において、
前記主体金具は、径方向に拡径された鍔部と、当該鍔部の後端側に形成される後端部とを有し、
前記外筒の前記先端を、前記後端部の径方向周囲を取り囲むように配置させつつ、前記鍔部の後端向き面に当接させる外筒配置工程と、
前記外筒の前記先端と前記主体金具の前記鍔部との境界付近に向けて全周にわたってレーザ溶接を行い、前記外筒の前記先端と前記主体金具の前記鍔部との間に跨って溶接部を形成する溶接工程と
を有することを特徴とするガスセンサの製造方法。 A detection element that extends in the axial direction and has a detection unit for detecting a gas to be detected on its tip side;
A metal shell that surrounds the periphery of the detection element in the radial direction while causing the detection unit to protrude from its tip,
A gas sensor manufacturing method comprising: a cylindrical outer cylinder fixed to the metal shell and surrounding a radial direction of the rear end side of the detection element;
The metal shell has a flange portion radially expanded in diameter, and a rear end portion formed on the rear end side of the flange portion,
An outer cylinder placement step of bringing the tip of the outer cylinder into contact with the rear-end-facing surface of the flange while placing the tip of the outer cylinder so as to surround the periphery of the rear end in the radial direction;
Laser welding is performed over the entire circumference toward the vicinity of the boundary between the tip of the outer cylinder and the flange of the metal shell, and welding is performed between the tip of the outer cylinder and the flange of the metal shell. And a welding process for forming the portion. 軸線方向に延びると共に、自身の先端側に被検出ガスを検出するための検出部を有する検出素子と、
前記検出部を自身の先端から突出させつつ、前記検出素子の径方向周囲を取り囲む主体金具と、
当該主体金具に固定され、前記検出素子の後端側の径方向周囲を取り囲む筒状の外筒と
を有するガスセンサの製造方法において、
前記主体金具は、径方向に拡径された鍔部と、当該鍔部の後端側に形成される後端部とを有し、
前記外筒の前記先端を、前記主体金具の前記鍔部とは離間しつつ前記後端部の径方向周囲を取り囲むように配置させる外筒配置工程と、
前記外筒の前記先端と前記主体金具の前記後端部との境界付近に向けて全周にわたってレーザ溶接を行い、前記外筒の前記先端と前記主体金具の前記後端部との間に跨って溶接部を形成する溶接工程と
を有することを特徴とするガスセンサの製造方法。 A detection element that extends in the axial direction and has a detection unit for detecting a gas to be detected on its tip side;
A metal shell that surrounds the periphery of the detection element in the radial direction while causing the detection unit to protrude from its tip,
A gas sensor manufacturing method comprising: a cylindrical outer cylinder fixed to the metal shell and surrounding a radial direction of the rear end side of the detection element;
The metal shell has a flange portion radially expanded in diameter, and a rear end portion formed on the rear end side of the flange portion,
An outer cylinder arranging step of arranging the front end of the outer cylinder so as to surround the rear end portion in the radial direction while being separated from the flange portion of the metal shell,
Laser welding is performed over the entire circumference toward the vicinity of the boundary between the tip of the outer cylinder and the rear end of the metal shell, and straddles between the tip of the outer cylinder and the rear end of the metal shell. And a welding process for forming a welded portion. 前記溶接工程では、前記溶接部の外表面が凹んだ曲面形状に形成されることを特徴とする請求項１７または１８に記載のガスセンサの製造方法。   The method for manufacturing a gas sensor according to claim 17 or 18, wherein in the welding step, the outer surface of the welded portion is formed in a curved shape.
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