JP2012233785A - Gas sensor - Google Patents

Abstract

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

Description

  The present invention relates to a gas sensor including a gas sensor element that detects the concentration of a gas to be detected.

As a gas sensor for detecting the concentration of a specific gas (oxygen or NO _x ) in exhaust gas of an automobile or the like, one having a gas sensor element using a solid electrolyte is known. As such a gas sensor, as shown in FIG. 7, it is a cylindrical shape extending in the direction of the axis O, and extends from the front end portion of the element main body 3s made of a solid electrolyte to the outer surface of the rear end portion, the detection portion 3cs, the lead A configuration including a gas sensor element 3 in which an outer electrode 3c including a portion 3cL and a connection portion 3cp is formed is known. In order to extract the output from the outer electrode 3c, the gas sensor is provided with an outer terminal 910 having a cylindrical portion 930 that surrounds the rear end portion of the gas sensor element 3 in the radial direction. The cylindrical portion 930 is a metal cylinder having a slit M in the axial direction O, is expanded in the radial direction by the gas sensor element 3, and is fitted on the rear end portion of the gas sensor element 3.
On the other hand, the outer terminal 910 is formed with a plate-like base portion 940 on the rear end side of the tubular portion 930, and is further crimped and connected to a core wire of a lead wire (not shown) at the rear end of the plate-like base portion 940. A connecting end 950 is disposed. The plate-like base portion 940 is inserted and held in an insertion hole (not shown) of the separator.

  In addition, a plurality of cut-and-raised portions 930 b and 934 that are bent inward in the radial direction are provided in a part of the cylindrical portion 930. Of these, the two cut-and-raised portions 930b are brought into contact with the connection portion 3cp of the outer electrode 3c, whereby the cylindrical portion 930 and the connection portion 3cp are electrically connected, and the cut-and-raised portions 930b and 934 are used. A technique for holding the gas sensor element 3 has been developed (Patent Document 1).

JP 2010-181347 A (FIGS. 3, 4, and 5) JP 2010-271284 A (FIGS. 1 and 4)

  However, in the case of the technique described in Patent Document 1, the cylindrical portion 930 is larger in diameter than the rear end portion of the gas sensor element 3 so that they are not in contact with each other, and the gas sensor element 3 is held only by the cut and raised 930 b and 934. In this case, since the cut-and-raised 930b and 934 only support the gas sensor element 3 with a point, there is room for improvement in terms of stable holding.

  On the other hand, while holding the rear end part of the gas sensor element in the cylindrical part as in Patent Document 2, the cylindrical part and the connecting part are brought into contact with the connecting part of the outer electrode. A technology for making electrical connections has also been developed. However, if the cylindrical portion moves relative to the gas sensor element, the cylindrical portion and the connecting portion are more likely to be separated due to a part of the cylindrical portion being separated from the gas sensor element. There is a risk that the reliability of the system will be reduced.

  Accordingly, an object of the present invention is to provide a gas sensor that can stably hold the outer terminal on the gas sensor element and that is less likely to reduce the reliability of electrical connection between the outer terminal and the gas sensor element even when the outer terminal moves relative to the gas sensor element. And

  In order to solve the above problems, a gas sensor according to the present invention includes a bottomed cylindrical element body that extends in the axial direction and whose tip is exposed to the gas to be measured, and the outer surface of the element body from the tip to the rear end A gas sensor comprising: a gas sensor element having an outer electrode provided; and an outer terminal having a cylindrical portion that surrounds a rear end portion of the gas sensor element from a radial direction and is electrically connected to the outer electrode. The cylindrical portion has a notch portion that is cut out of the cylindrical portion and elastically deformable in the radial direction, and a convex portion that is disposed in the notch portion and protrudes radially inward. The tubular portion holds the rear end portion of the gas sensor element, and the convex portion comes into contact with the outer electrode while the notch portion is elastically deformed in the radial direction.

According to this gas sensor, the mechanical holding of the rear end portion of the gas sensor element and the outer terminal is positively performed in the cylindrical portion excluding the notch portion, while the electrical connection between the outer terminal and the outer electrode is performed. The connection is made with a convex portion arranged in a notch that elastically deforms in the radial direction. For this reason, since the entire cylindrical portion contacts the rear end portion of the gas sensor element with a line or a surface, the gas sensor element can be stably held, and the cylindrical portion can be moved even if the cylindrical portion moves relative to the gas sensor element. The notch that moves independently from each other absorbs the movement, so that the convex portion arranged in the notch and the outer electrode can be reliably brought into contact with each other, and the electrical connection between the outer terminal and the outer electrode is reliable. It is hard to be lowered.
In addition, since the electrical contact with the outer electrode always becomes the position of the convex portion, and the position of the electrical contact in the axial direction is specified, the formation position of the outer electrode can be limited to the vicinity of this position. Thereby, the length of an outer electrode can be shortened, the usage-amount of the material (noble metal etc.) used for an outer electrode reduces, and cost reduction is aimed at.

Furthermore, in the gas sensor according to the present invention, the outer electrode is provided on a detection portion provided over the entire circumference on the front end side of the element body and on a part of the circumferential direction on the rear end side of the element body. And a plurality of cutout portions provided in the circumferential direction, and the connection portion is in contact with the convex portion of at least one cutout portion. It is good to be.
According to this gas sensor, by providing a plurality of cutout portions in the circumferential direction, even if the connection portion is provided in a part of the circumferential direction, the convex portion arranged in at least one cutout portion is surely provided in the connection portion. The reliability of the electrical connection between the outer terminal and the outer electrode is unlikely to be lowered. In addition, it is not necessary to provide the outer electrode on the entire periphery of the rear end portion of the element body, so that the amount of the material (noble metal or the like) used for the connection portion is reduced and the cost is reduced.

Furthermore, in the gas sensor of the present invention, when the cylindrical portion is divided into three regions at intervals of 120 degrees when viewed in the axial direction, at least one notch portion may be disposed in each region. .
According to this gas sensor, there is a high possibility that any one of the convex portions comes into contact with the outer electrode, and it is preferable because reliable conduction between the outer terminal and the outer electrode is achieved.

  Furthermore, in the gas sensor according to the present invention, when the notches are arranged at equal intervals in the circumferential direction, the convex portions do not come into contact with the outer electrode, and the outer terminals and the outer electrodes are easily contacted. Since reliable conduction is achieved, it is preferable.

  Furthermore, in the gas sensor according to the present invention, when the cylindrical portion is formed with a slit extending in the axial direction from the front end edge to the rear end edge of the cylindrical portion and formed in a C-shaped cross section, the cylindrical portion is When the tube is externally fitted and expanded, the cylindrical portion is contracted by the spring force and pressed by the gas sensor element, so that the gas sensor element can be held more stably. In addition, it cannot be overemphasized that the internal diameter of the cylindrical part in the free state (state before hold | maintaining the rear-end part of a gas sensor element) is smaller than the outer diameter of a gas sensor element.

  According to the present invention, the outer terminal can be stably held on the gas sensor element, and even if the outer terminal moves relative to the gas sensor element, the reliability of the electrical connection between the two is hardly lowered.

It is sectional drawing which cut | disconnected the gas sensor which concerns on embodiment of this invention by the surface which follows an axial direction. It is a perspective view which shows the structure of a gas sensor element and an outer side terminal. It is a perspective view which shows the state which fitted the cylindrical part of the outer side terminal to the outer peripheral surface of the rear end side of a gas sensor element. It is sectional drawing which cut | disconnected FIG. 3 by the plane perpendicular | vertical to an axial direction. FIG. 6 is a cross-sectional view when the gas sensor element moves in a direction perpendicular to the axial direction (arrow A in FIG. 5) in FIG. 4. It is a figure which shows the aspect which assembles | assembles a separator assembly and a sensor element assembly, and manufactures a gas sensor. It is a perspective view which shows the structure of the conventional outer side terminal.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a cross-sectional structure in which a gas sensor 100 according to an embodiment of the present invention is cut along a plane along an axis O direction (a direction along the rear end from the front end). In this embodiment, the gas sensor 100 is an oxygen sensor that is inserted into an exhaust pipe of an automobile and the tip (the protector 7 side in FIG. 1) is exposed to the exhaust gas to detect the oxygen concentration in the exhaust gas.
The lower side (the protector 7 side) in FIG. 1 is the front end side of the gas sensor 100, and the upper side in FIG.

In the gas sensor 100, the gas sensor element 3 is assembled in a housing (metal shell) 20. Among these, the gas sensor element 3 is a known oxygen gas sensor element that constitutes an oxygen concentration cell in which a pair of electrodes are stacked on an oxygen ion conductive solid electrolyte body and outputs a detection value corresponding to the amount of oxygen. Specifically, the gas sensor element 3 includes a bottomed cylindrical solid electrolyte body (corresponding to the “element body” in the claims, see FIG. 2) that tapers toward the tip, and a solid electrolyte body. It consists of an inner electrode 3b and an outer electrode 3c respectively formed on the inner peripheral surface and the outer peripheral surface. Then, the internal space of the gas sensor element 3 is set as a reference gas atmosphere, and the gas to be detected is brought into contact with the outer surface of the gas sensor element 3 to detect the gas.
Near the center of the gas sensor element 3, a flange 3 a that protrudes radially outward is provided. On the other hand, on the inner peripheral surface near the tip of the housing 20, a step portion 20e having a diameter reduced inward is provided, and the packing 12 is disposed between the flange portion 3a and the step portion 20e. Then, the gas sensor element 3 is inserted into the inside of the housing 20, and the flange 3 a is applied to the packing 12, so that the flange 3 a of the gas sensor element 3 is indirectly brought into contact with the stepped portion 20 e from the rear end side. Is assembled in the housing 20.

  Further, a cylindrical seal material (talc powder) 6 is filled in a radial gap between the gas sensor element 3 and the housing 20 on the rear end side of the flange 3 a, and a cylindrical shape is further formed on the rear end side of the seal material 6. An insulating member (ceramic sleeve) 31 is disposed. Then, a metal ring (stainless flat washer) 30 is disposed on the rear end side of the insulating member 31 and the rear end portion of the housing 20 is bent inward to form the crimped portion 20a. The insulating material 31 and the sealing material 6 are crimped and fixed by being pressed against the distal end side, and the gap between the gas sensor element 3 and the housing 20 is sealed.

  Further, a metal cylindrical outer cylinder 40 is joined to the rear end of the housing 20 in order to cover the rear end portion of the gas sensor element 3. For the outer cylinder 40, for example, stainless steel such as SUS430, SUS304, SUS304L, SUS310S, SUS316, SUS316L, or the like can be used. The outer cylinder 40 has a front end portion 40a connected to the housing 20 and a rear end portion 40b having a diameter smaller than that of the front end portion 40a. A stepped portion 43 is provided between the front end portion 40a and the rear end portion 40b. Is provided.

  An insulating cylindrical separator 111 is disposed on the inner side surface of the distal end portion 40 a of the outer cylinder 40. Further, the plate-like base portions 74 and 94 of the inner terminal 71 and the outer terminal 91 are inserted and fixed in the two insertion holes 115 and 116 of the separator 111, respectively. Connection end portions 75 and 95 are formed at the rear ends of the plate-like base portions 74 and 94, respectively, and lead wires 141 and 141 are caulked and connected to the connection end portions 75 and 95, respectively.

  In addition, the separator 111 abuts the inner end of the outer cylinder 40 by bringing the front end surface of the separator 111 into contact with the holding metal fitting 45 disposed on the front end side of the separator 111 while bringing the rear end surface of the separator 111 into contact with the stepped portion 43. Retained. The holding metal fitting 45 is disposed on the front end side of the separator 111, and is fixed in the outer cylinder 40 by crimping the front end portion 40 a of the outer cylinder 40.

  The inner terminal 71 is provided with an insertion portion 73 that is connected to the plate-like base portion 74 and is fitted into the cylindrical hole 3 d of the gas sensor element 3. The insertion portion 73 has a cylindrical shape and is electrically connected to an inner electrode 3 b provided on the inner side of the gas sensor element 3. In addition, the outer terminal 91 is provided with a cylindrical portion 93 that is externally fitted to the outer side of the gas sensor element 3 with a connector on the plate-like base 94. The tubular portion 93 has a tubular shape and is electrically connected to the outer electrode 3 c provided outside the gas sensor element 3. Details of the outer terminal 91 will be described later.

  A cylindrical grommet 131 is inserted inside the rear end portion 40b of the outer cylinder 40 and fixed by crimping. In the grommet 131, lead wires 141 and 141 are drawn out from the two insertion holes, respectively. Further, the rear end side of the grommet 131 is enlarged in a flange shape, and the grommet 131 is positioned by placing this enlarged diameter portion on the rear end of the outer cylinder 40. As the grommet 131, for example, a rubber cap made of silicon rubber, fluorine rubber, or the like can be used.

  Further, on the side surface of the rear end portion 40b of the outer cylinder 40, four first vent holes 41 (only three are shown in FIG. 1) are arranged at equal intervals in the circumferential direction at a position closer to the front end side than the grommet 131. It is open. An annular breathable filter 50 is covered on the radially outer side of the rear end portion 40b of the outer cylinder 40 so as to close the first ventilation hole 41. Further, the filter 50 is made of a metal cylinder from the radially outer side. A cylindrical protective outer cylinder 60 surrounds. For example, stainless steel such as SUS430, SUS304, SUS304L, SUS310S, SUS316, and SUS316L can be used for the protective outer cylinder 60. Four second vent holes 61 (only two are shown in FIG. 1) are opened at equal intervals in the circumferential direction on the side surface of the protective outer cylinder 60, and the outside air can be introduced into the outer cylinder 40 through the filter 50. It has become. The filter 50 is held between the outer cylinder 40 and the protective outer cylinder 60 by crimping the outer cylinder 40 and the protective outer cylinder 60 before the second ventilation hole 61 and the first ventilation hole 41. The filter 50 is made of, for example, a porous structure of resin such as fluorine resin, and has water repellency, and therefore introduces a reference gas (atmosphere) into the internal space of the sensor element 3 without passing external water.

  The protective outer cylinder 60 is bent radially inward so that the rear end portion is provided on the rear end surface of the grommet 131, and an opening 63 is formed at the center of the rear end portion, and lead wires 141 and 141 are formed from the opening. Has been pulled out. Further, on the rear end side of the protective outer cylinder 60, it is fixed by caulking to a caulking portion provided at the rear end portion 40b of the outer cylinder 40. That is, the grommet 131 is disposed in the outer cylinder 40 by simultaneously caulking both the protective outer cylinder 60 and the outer cylinder 40.

  On the other hand, a cylindrical protector 7 made of metal (such as stainless steel) is fixed to the distal end portion 20 f of the housing 20, and the distal end of the gas sensor element 3 protruding from the housing 20 is covered with the protector 7. The protector 7 has a plurality of holes for taking the exhaust gas into the protector 7.

In the vicinity of the center of the housing 20, a polygonal flange portion 20c that protrudes radially outward and engages with a hexagon wrench or the like is provided, and is formed on the outer surface of the housing 20 between the flange portion 20c and the tip portion 20f. Has a male screw portion 20d. Further, a gasket (not shown) for preventing gas escape when attached to the exhaust pipe is fitted into a step portion between the front end surface of the flange portion 20c and the rear end of the male screw portion 20d.
Then, by attaching the male screw portion 20d of the housing 20 to a screw hole such as an exhaust pipe, the tip of the gas sensor element 3 is exposed in the exhaust pipe to detect the detected gas (exhaust gas).

Next, the configuration of the outer terminal 91, which is a characteristic part of the present invention, will be described with reference to FIGS. The outer terminal 91 extends from the front end to the rear end and is integrally formed by bending a thin metal plate (corrosion-resistant heat-resistant superalloy plate) punched into a predetermined shape. A plate-like base portion 94 is formed on the rear end side of the outer terminal 91, and a connection end portion 95 that is caulked and connected to the core wire of the lead wire 141 is disposed on the rear end side of the plate-like base portion 94. A cylindrical portion 93 is connected to the distal end side of the plate-like base portion 94. Further, a wide portion 94w that is wider than other portions is formed on the center side in the axial direction of the plate-like base portion 94, and the central portion of the wide portion 94w is punched into a U-shape with the rear end side fixed, and the wide portion 94w A cut-and-raised portion 94Y cut and raised on the back side (the surface opposite to the front side) is provided.
When the plate-like base portion 94 is inserted into the insertion hole 116 (see FIG. 6) of the separator 111, the plate-like base portion 94 is positioned in the insertion hole 116. Further, the cut and raised portion 94Y contacts the outer end wall of the insertion hole 116, and the plate-like base portion 94 is held in the insertion hole 116 by the spring force.

On the other hand, the cylindrical portion 93 has a cylindrical shape centering on an axis connecting the rear end and the distal end, and has a slit M along the generatrix on the opposite side to the plate-shaped base portion 94. The inner diameter of the cylindrical portion 93 is smaller than the outer diameter of the rear end portion of the gas sensor element 3, and when the cylindrical portion 93 is fitted on the gas sensor element 3 and expanded, the cylindrical portion 93 is contracted by the spring force. The gas sensor element 3 is pressed against the outer electrode 3c.
Further, in the vicinity of the center of the cylindrical portion 93 in the direction of the axis O, five cutout portions 93a are formed at equal intervals in the circumferential direction (only three are shown in FIG. 2). ing. And in the center of each notch part 93a, the square convex part (dowel) 93b which protrudes to radial inside is provided. Here, one side parallel to the direction of the axis O of the notch portion 93a is a fixed end, and the notch portion 93a can be elastically deformed (reduced diameter and expanded diameter) in the radial direction with the fixed end as a fulcrum. is there. The convex portion 93b electrically connects the outer terminal 91 and the outer electrode 3c (a connecting portion 3cp described later). In this embodiment, the convex portion 93b protrudes from the notch portion 93a by press working. .
In a free state in which no force is applied in the radial direction of the cutout portion 93a, the cutout portion 93a is flush with the plate surface of the cylindrical portion 93, but a force is applied to the cutout portion 93a. When the outer terminal 91 moves relative to the gas sensor element 3 as will be described later, the notch portion 93a moves as described below. Therefore, it is difficult to reduce the reliability of electrical connection. Further, in order to make the electrical connection between the convex portion 93b and the outer electrode 3c more reliable, it is preferable to adjust (for example, increase) the protruding height of the convex portion 93b.

Here, as shown in FIG. 2, the outer electrode (detection electrode) 3c is formed on the distal end side of the outer surface of the element body 3s of the gas sensor element 3, and the outer electrode 3c extends over the entire circumference on the distal end side of the element body 3s. A detection part 3cs provided in a linear manner, a linear lead part 3cL extending from the detection part 3cs to the rear end, and a lead part 3cL (detection part) provided so as to extend partly in the circumferential direction on the rear end side of the element body 3s. 3cs) and a connecting portion 3cp. And the convex part 93b of the cylindrical part 93 is connected to the connection part 3cp.
The connecting portion 3cp is formed with a width (width S ₁ ) wider than the lead portion 3cL in the circumferential direction, and the connecting portion 3c and the lead portion 3cL form a T shape. The inner electrode 3b (see FIG. 1) is provided on the surface of the inner hole 3d from the front end portion to the rear end portion of the element body 3s.

  Then, as shown in FIG. 3, the cylindrical portion 93 of the outer terminal 91 is fitted on the outer peripheral surface on the rear end side of the gas sensor element 3, and the outer electrode 3 c (connection portion 3 cp) on the outer surface of the gas sensor element 3 is connected to the cylindrical shape. The part 93 (convex part 93b) is brought into contact. Further, when the gas sensor element 3 is externally fitted, the cylindrical portion 93 is expanded, and the cylindrical portion 93 is contracted by the spring force, so that the gas sensor element 3 is firmly held by the cylindrical portion 93.

4 is a cross-sectional view of FIG. 3 cut along a plane perpendicular to the axial direction O. FIG. Since the cylindrical portion 93 is contracted by the elastic force, it does not become a perfect circle, but the cylindrical portion 93 and the outer surface of the gas sensor element 3 come into contact with each other at several positions in the circumferential direction. 93. Here, since the cylindrical portion 93 is formed in a C-shape having the slit M, the cylindrical portion 93 is in the vicinity of the slit M and at a position facing the slit M (a position connected to the plate-shaped base portion 94). Although contacting the gas sensor element 3, a gap G is formed with the gas sensor element 3 on the side of FIG.
In this case, at the position where the cylindrical portion 93 is in contact with (adjacent to) the gas sensor element 3, the notch portion 93a largely escapes outward in the radial direction, so that the convex portion 93b in the notch portion 93a comes into contact with the connection portion 3cp. . Further, at the side position where the cylindrical portion 93 is spaced apart from the gas sensor element 3 and has the gap G, the convex portion 93b comes into contact with the connecting portion 3cp by escaping to the outside in the radial direction of the notch portion 93a.

5 is a cross-sectional view when the gas sensor element 3 in FIG. 4 moves in a direction perpendicular to the axial direction O (arrow A in FIG. 5). When the gas sensor element 3 moves to the left side (arrow A in FIG. 5) in the cylindrical portion 93, the left side of the cylindrical portion 93 is more in contact with the gas sensor element 3, while the gap G on the right side of the cylindrical portion 93 is growing.
In this case, on the left side of the tubular portion 93, the notch portion 93a largely escapes radially outward, so that the contact between the convex portion 93b in the notch portion 93a and the connection portion 3cp is maintained. On the other hand, on the right side of the cylindrical portion 93, the notch portion 93a returns to the inner side in the radial direction (reduces its diameter), so that the contact between the convex portion 93b and the connection portion 3cp is maintained. Since the cutout portion 93a is elastically deformed in the radial direction according to the distance between the cylindrical portion 93 and the outer surface of the gas sensor element 3 in this way, the convex portion 93b in the cutout portion 93a is always connected to the connection portion 3cp. Pressed by 3 cp, a reliable electrical connection between the gas sensor element 3 and the cylindrical portion 93 is maintained.

As described above, the mechanical holding of the rear end portion of the gas sensor element 3 and the outer terminal 91 is positively performed by the cylindrical portion 93 excluding the notch portion 93a, while the outer terminal 91, the outer electrode 3c, The electrical connection is performed by a convex portion 93b disposed in a notch portion 93a that is elastically deformed in the radial direction.
For this reason, since the whole cylindrical part 93 contacts the rear end part of the gas sensor element 3 with a line or a surface, the gas sensor element 3 can be stably held, and the cylindrical part 93 moves relative to the gas sensor element 3. In addition, since the cutout portion 93a that moves independently of the cylindrical portion 93 absorbs the movement, the convex portion 93b disposed in the cutout portion 93a and the outer electrode 3c can be reliably brought into contact with each other. The reliability of the electrical connection between the terminal 91 and the outer electrode 3c is hardly lowered.
The fitting depth of the cylindrical portion 93 to the gas sensor element 3 is determined in advance according to the position of the cylindrical portion 93 in the axis O direction when being fixed to the outer cylinder 40 (see FIG. 7). Further, in the present invention, the electrical contact with the outer electrode 3c is always the position of the convex portion 93b. Therefore, the position of the electrical contacts in the axial direction O is identified, can be limited to the contact near the length S ₂ of the axial O of the connection portion 3cp as shown in FIG. 2, the connecting portion The amount of materials (noble metals, etc.) used for 3cp is reduced, and the cost is reduced.

  Further, by providing a plurality of cutout portions 93a in the circumferential direction, even if the connection portion 3cp is provided in a part of the circumferential direction, the convex portion 93b disposed in at least one cutout portion 93a is connected to the connection portion 3cp. The reliability of the electrical connection between the outer terminal 91 and the outer electrode 3c is difficult to be lowered. In addition, it is not necessary to provide the outer electrode 3c on the entire circumference of the rear end portion of the element body 3s, so that the amount of a material (noble metal or the like) used for the connection portion 3cp is reduced and the cost can be reduced.

In particular, in the embodiment of FIG. 2, the connecting portion 3cp is formed with a width S ₁ in the circumferential direction, while the outside terminal 91, (distance = protrusions 93 b) circumferential spacing between adjacent notches 93a S ₃ is formed. At this time, by satisfying the relationship of S ₃ <S ₁ , at least one or more protrusions 93b always come into contact with the connection portion 3cp regardless of the circumferential direction of the outer terminal 91 with respect to the connection portion 3cp. . Therefore, a contact can be secured without aligning the outer electrode 3c and the outer terminal 91, and assembly is facilitated. Note that the intervals in the circumferential direction of the notches 93a (= projections 93b) may not be equal, and the maximum one of the intervals between the adjacent notches 93a satisfies the relationship of S ₃ <S _1. The above effects can be achieved.

Further, when the cylindrical portion 93 is divided into three regions at intervals of 120 degrees when viewed in the axial direction O, if at least one notch portion 93a is arranged in each region, any one of the convex portions 93b This is preferable because the ratio of contact with the outer electrode 3c is increased and reliable conduction between the outer terminal 91 and the outer electrode 3c is achieved.
Further, when the notches 93a are arranged at equal intervals in the circumferential direction, the convex portions 93b do not come into contact with the outer electrode 3c evenly, and the outer terminals 91 and the outer electrodes 3c are reliably contacted. Since conduction is achieved, it is preferable.

  Next, a manufacturing method of the gas sensor 100 will be described with reference to FIG. First, the sensor element assembly B is assembled while holding the gas sensor element 3 inside the metal shell 20. Specifically, the gas sensor element 3 is disposed on the packing 12 disposed in the metal shell 20. Thereafter, the seal material 6 is filled in the gap between the metal shell 20 and the gas sensor element 3, the insulating member 31 and the metal ring 30 are sequentially disposed on the seal material 6, and the rear end side of the metal shell 2 is crimped to form the sensor element. Assemble assembly B. On the other hand, the separator 111 assembled with the inner terminal 71 and the outer terminal 91 is arranged together with the grommet 131 in the outer cylinder 40, and the separator assembly A is assembled. Specifically, the inner terminal 71 and the outer terminal 91 connected to the lead wire 141 are inserted into the insertion holes 115 and 116 of the separator 111, and then the separator 111 is brought into contact with the step portion 43 of the outer cylinder 40. Thereafter, the holding metal fitting 45 is inserted into the gap between the separator 111 and the outer cylinder 4, and the distal end portion 40 a of the outer cylinder 40 is fixed by crimping. Further, the grommet 131 is inserted from the rear end of the outer cylinder 40, and the filter 50 and the protective outer cylinder 60 are respectively arranged on the rear end portion 40b of the outer cylinder 40, and the filter 50 and the grommet 131 are respectively fixed by crimping. Then, the separator assembly A is assembled. When the separator assembly A is aligned with the axis of the sensor sensor element assembly B and the separator assembly A is put on the rear end of the sensor element assembly B, the cylindrical insertion portion 73 of the inner terminal 71 is connected to the rear end of the gas sensor element 3. It is fitted in the cylindrical hole 3d and is electrically connected to the inner electrode (reference electrode) 3b on the inner surface of the gas sensor element 3. The cylindrical portion 93 of the outer terminal 91 is fitted on the outer peripheral surface of the rear end side of the gas sensor element 3 and is electrically connected to the outer electrode (detection electrode) 3c on the outer surface of the gas sensor element 3. And the front-end | tip part of the outer cylinder 40 is fitted by the housing 20, and the outer peripheral surface of the front-end | tip part of the outer cylinder 40 is connected to the rear-end part of the metal shell 20 by laser welding etc., and the gas sensor 100 is manufactured.

It goes without saying that the present invention is not limited to the above-described embodiment, but extends to various modifications and equivalents included in the spirit and scope of the present invention.
The number of cutouts is not limited as long as one or more cutouts are formed, and the shape of the cutouts is not limited. For example, the cutout portion may be cut out in a U shape. The position of the fixed end of the notch may also be the front end side or the rear end side instead of the side as shown in FIG.
The number of convex portions arranged inside one notch may be one or more, and the shape of the convex portions is not limited. However, if one protrusion is arranged inside one notch, the position of the contact point with the outer electrode becomes clear and the notch becomes a notch when the outer terminal moves relative to the gas sensor element. It is preferable because the movement is easy to convey. Further, for the same reason, the convex portion may be arranged at a position that becomes the center of gravity of the notch portion.
Further, the present invention is not limited to a heaterless sensor, but can be applied to a gas sensor having a heater.
Furthermore, as a gas sensor element, as long as it is a cylindrical element, it can be used for an ammonia sensor element, an HC sensor element, an H ₂ sensor element, etc., in addition to the oxygen sensor element (λ sensor element) described above.

DESCRIPTION OF SYMBOLS 3 Gas sensor element 3c Outer electrode 3cs Detection part 3cp Connection part 3s Element main body 91 Outer terminal 93 Cylindrical part 93a Notch part 93b Protrusion part 100 Gas sensor O Axis direction M Slit

Claims (5)

A gas sensor element having a bottomed cylindrical element body that extends in the axial direction and whose tip is exposed to the gas to be measured; and an outer electrode provided on the outer surface of the rear end from the tip of the element body;
An outer terminal having a cylindrical portion surrounding the rear end portion of the gas sensor element from the radial direction and electrically connected to the outer electrode;
The cylindrical part has a notch part that is notched in the cylindrical part and can be elastically deformed in the radial direction, and a convex part that is arranged in the notch part and protrudes radially inward.
A gas sensor in which the cylindrical portion holds a rear end portion of the gas sensor element, and the protruding portion is in contact with the outer electrode while the cutout portion is elastically deformed in a radial direction. The outer electrode is provided on a part of the circumferential direction on the rear end side of the element body, and is provided between the detection part and the outer terminal. And a connection part for connecting
2. The gas sensor according to claim 1, wherein a plurality of the cutout portions are provided in a circumferential direction, and the connection portion is in contact with the convex portion of at least one cutout portion.   3. The gas sensor according to claim 1, wherein when the cylindrical portion is divided into three regions at intervals of 120 degrees when viewed in the axial direction, at least one notch portion is disposed in each region.   The gas sensor according to claim 3, wherein the notches are arranged at equal intervals in the circumferential direction.   The gas sensor according to any one of claims 1 to 4, wherein the cylindrical portion is formed with a slit extending in the axial direction from a leading edge to a trailing edge of the cylindrical portion, and is formed in a C-shaped cross section.

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