JP2014035242A - Gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the assembly operation of a gas sensor and to suppress a damage to an inner electrode.SOLUTION: A gas sensor includes: a sensor element having an inner electrode provided on an inner surface of a solid-state electrolyte body; a lead line; and a cylindrical part which is inserted into the sensor element and in contact with the inner electrode. The gas sensor further includes: a connection terminal for electrically connecting the inner electrode and the lead line through the cylindrical part; a main metal fitting; and an outer cylinder surrounding the connection terminal. The cylindrical part is located at a rear end side than a tip of the outer cylinder. The connection terminal extends until reaching a tip side position further than the tip of the outer cylinder from a part of the tip of the cylindrical part, and incudes a plate-like extension part inserted into a cylinder aperture of the sensor element. The extension part has a bent part to bend in a plate thickness direction so as to approach an axial line of the sensor element in a rear end part close to the connection part with the cylindrical part, and a region of the tip side than the bent part is separated from an inner surface of the sensor element.

Description

  The present invention relates to a gas sensor.

  As a gas sensor for detecting a specific gas component in a gas to be measured, a sensor having a sensor element whose electrical characteristics change according to the concentration of the specific gas component in the gas to be measured has been known. As such a sensor element, for example, a bottomed cylindrical solid electrolyte having a closed tip, an inner electrode (reference electrode) formed on the inner surface of a cylindrical hole of the solid electrolyte, and an outer surface of the solid electrolyte A sensor element including an outer electrode (detection electrode) formed is known. When incorporating such a sensor element into a gas sensor, for example, a connection terminal fitting connected to a lead wire provided in the gas sensor is prepared in order to extract a detection signal from the gas sensor. Is inserted. For example, in order to connect the lead wire and the inner electrode of the sensor element, the connection terminal fitting connected to the lead wire is fitted into the cylindrical hole of the sensor element, and the connection terminal fitting and the inner electrode are brought into contact with each other. Good.

  As such a gas sensor, a sensor having a heater for heating a sensor element has been conventionally known (for example, see Patent Document 1). Such a heater generally heats the sensor element from the inside by being arranged inside a connection terminal fitting connected to the inner electrode.

  In general, the gas sensor is manufactured by separately assembling the structure on the front end side including the sensor element and the structure on the rear end side including the outer cylinder in which the lead wire and the connection terminal fitting are assembled, and then assembling the two. Is done by. When manufacturing a gas sensor having a heater, the heater is first assembled with the connection terminal fitting in the outer cylinder in the structure on the rear end side, and further protrudes in the distal direction from the distal end of the outer cylinder. . Therefore, when assembling the gas sensor, the heater protruding from the front end of the outer cylinder included in the structure on the rear end side is inserted into the cylinder hole of the sensor element included in the structure on the front end side, and the structure on the front end side and the rear end described above. Assembly with the side structure is performed. As a result, the connection terminal fitting is fitted into the sensor element simultaneously with the assembly of the front end side structure and the rear end side structure. Thus, when the gas sensor is assembled, the heater protruding from the tip of the outer cylinder functions as a guide for the assembling operation.

JP 2007-278806 A

  On the other hand, in recent years, in order to simplify the assembly operation by simplifying the configuration of the gas sensor, to reduce the size of the gas sensor, or to reduce the cost of the gas sensor, it is desired to have a configuration in which no heater is provided in the gas sensor. . However, when the gas sensor is not provided with a heater, when manufacturing the gas sensor separately for the front end side structure and the rear end side structure, there is no heater that guides the assembly operation of the two, so the assembly operation is difficult. There was a problem of becoming. Specifically, it is difficult to align the tip of the connection terminal fitting and the opening of the sensor element cylinder hole when fitting the connection terminal fitting arranged inside the outer cylinder into the cylinder hole of the sensor element. There was a problem of becoming.

  Here, a measure for providing a structure for guiding the alignment between the connection terminal fitting and the opening of the cylindrical hole in the structure on the rear end side is also conceivable. However, in such a case, when the guiding structure contacts the inner electrode, the inner electrode is damaged. Therefore, a measure for suppressing such damage to the inner electrode is required. Even when a heater serving as a guide is not provided, the electrical connection between the connection terminal electrode and the inner electrode can be reliably performed by the assembling operation of the structure on the front end side and the structure on the rear end side. desired.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

(1) According to one aspect of the present invention, a solid electrolyte body made of a solid electrolyte formed in a bottomed cylindrical shape with a bottom extending on the tip end side in the axial direction, and provided on the inner surface of the solid electrolyte body An inner electrode; a lead wire for taking out a detection signal of the sensor element; and a cylindrical shape that is elastically deformable in a radial direction and is inserted into the sensor element to contact the inner electrode A connecting terminal that electrically connects the inner electrode and the lead wire through the cylindrical portion, a metal shell that surrounds the sensor element, and a rear end side of the metal shell, There is provided a gas sensor including an outer cylinder surrounding the connection terminal. In this gas sensor, the cylindrical portion is positioned on the rear end side with respect to the front end of the outer cylinder, and the connection terminal is further on the front end side than the front end of the outer cylinder with a part of the front end of the cylindrical portion. And a plate-like extension portion inserted into the cylindrical hole of the sensor element. Further, the extending portion has a bent portion that bends in the thickness direction of its own so as to approach the axis of the sensor element at the rear end portion in the vicinity of the connecting portion with the cylindrical portion, and more than the bent portion. The site | part of the front end side is spaced apart from the inner surface of the said sensor element. According to the gas sensor of this aspect, since the extending portion extending to the position closer to the distal end side than the distal end of the outer cylinder is provided, the extending portion is inserted into the sensor element. It can be used as a guide for the operation to facilitate the assembly operation of the gas sensor. Moreover, since the extension part has a bending part and the site | part of the front end side of the extension part is spaced apart from the inner surface of a sensor element, damage to the inner side electrode by an extension part can be suppressed.

(2) In the gas sensor according to the above aspect, the connection terminal may include a rigidity imparting portion that is provided apart from the inner surface of the sensor element and increases the rigidity of the extension portion. According to the gas sensor of this aspect, since the rigidity of the extension portion is increased, deformation of the extension portion can be suppressed. Therefore, handling of the connection terminal can be facilitated, and damage to the inner electrode due to the deformed extension portion can be suppressed.

(3) In the gas sensor according to the above aspect, the connection terminal includes a plurality of extending pieces that extend from the part of the tip of the cylindrical part to a position closer to the tip than the tip of the outer cylinder as the extension. The rigidity imparting portion may be a distal end fixing portion that fixes the vicinity of the distal ends of the plurality of extending pieces. According to this type of gas sensor, the extension portions can be provided with rigidity by fixing the vicinity of the ends of the extension pieces with the tip fixing portion.

(4) In the gas sensor of the above aspect, the tip fixing portion may include a tip connecting portion that is provided between the adjacent extending pieces and connects the vicinity of the tip ends of the adjacent extending pieces. According to this type of gas sensor, the extension portion can be provided with rigidity by connecting the vicinity of the ends of the extension pieces with the tip connection portion.

(5) In the gas sensor of the above aspect, the tip connection part may include a folded part folded so as to approach the axis of the sensor element. According to the gas sensor of this form, damage to the inner electrode due to the tip connection portion can be suppressed.

(6) In the gas sensor according to the above aspect, the connection terminal may be one or a plurality of extensions that extend from a part of the tip of the cylindrical portion to a position closer to the tip than the tip of the outer cylinder as the extension. It is good also as providing the protrusion piece and the said rigidity provision part being a recessed part or a convex part provided in each said extended piece. According to the gas sensor of this form, rigidity can be imparted to the extended portion by the concave portion or the convex portion.

(7) In the gas sensor according to the above aspect, the connection terminal may be one or a plurality of extensions that extend from a part of the tip of the cylindrical portion to a position closer to the tip than the tip of the outer cylinder as the extension. Provided with a protruding piece, the rigidity imparting portion may be a reinforcing portion fixed on at least one surface of each of the extending pieces. According to the gas sensor of this aspect, rigidity can be imparted to the extended portion by fixing the reinforcing portion on the surface of the extended piece.

(8) In the gas sensor according to the above aspect, the connection terminal may be one or a plurality of extensions that extend from a part of the tip of the cylindrical portion to a position closer to the tip than the tip of the outer cylinder as the extension. It is good also as a bending part which provided the protruding piece and the said rigidity provision part bent each said extending piece along the axial direction. According to the gas sensor of this aspect, rigidity can be imparted to the extended portion by bending the extended piece to form the bent portion.

(9) In the gas sensor according to the above aspect, each of the rigidity imparting portions may be arranged from each extending piece to a position on the rear end side with respect to a connecting portion between each extending piece and the tubular portion. It is good also as being provided ranging over the said bending part of the extension piece. According to the gas sensor of this aspect, the strength of the region including the connection portion between the extension piece and the cylindrical portion can be increased, and the effect of suppressing the deformation of the extension portion can be increased.

(10) In the gas sensor of the above aspect, the rigidity imparting portion may be provided so as to extend in the axial direction up to the tip of the extension piece in each extension piece. According to the gas sensor of this form, it is possible to increase the rigidity up to the tip of the extension piece and suppress the deformation of the extension part.

  The present invention can be realized in various forms other than those described above. For example, the present invention can be realized in a form such as a gas sensor manufacturing method.

It is sectional drawing showing the structure of a gas sensor. It is a perspective view showing the external appearance of a sensor element. It is a perspective view showing the outline of the appearance of the 1st connecting terminal. It is a top view showing the schematic shape of the plate-shaped member for forming the 1st connecting terminal. It is a perspective view showing the appearance of the 2nd connecting terminal. It is explanatory drawing which shows the outline | summary of an assembly of a gas sensor. It is a perspective view showing the outline of the appearance of the 1st connecting terminal. It is a perspective view showing the outline of the appearance of the 1st connecting terminal. It is a perspective view showing the outline of the appearance of the 1st connecting terminal. It is a perspective view showing the outline of the appearance of the 1st connecting terminal.

A. First embodiment:
FIG. 1 is a sectional view showing the configuration of a gas sensor 100 as a first embodiment according to the present invention. As shown in FIG. 1, the gas sensor 100 has an elongated shape that extends along the axis O. In the following description, the lower side in FIG. 1 in the direction of the axis O is referred to as the front end side, and the upper side in FIG. 1 is referred to as the rear end side. The gas sensor 100 of the present embodiment is an oxygen concentration sensor, and can be used, for example, to detect the oxygen concentration in the exhaust gas of an automobile.

  The gas sensor 100 includes a sensor element 10, a metal shell (housing) 20, an outer cylinder 40, and a structure (electrode and wiring connected to the electrode) related to routing of the internal wiring of the gas sensor as main components. ing. The sensor element 10 constitutes an oxygen concentration cell in which a pair of electrodes are laminated on both surfaces of an oxide ion conductive (oxygen ion conductive) solid electrolyte body, and outputs a detected value corresponding to the oxygen partial pressure. It is a sensor element. Specifically, the sensor element 10 includes a bottomed cylindrical solid electrolyte body 11 whose outer diameter is tapered toward the tip, and inner electrodes formed on the inner surface and the outer surface of the solid electrolyte body 11, respectively. (Reference electrode) 10a and outer electrode (detection electrode) 10b. Then, the inner space of the sensor element 10 is set as a reference gas atmosphere, and the gas to be detected is brought into contact with the outer surface of the sensor element 10 to detect the gas. From the rear end of the gas sensor 100, two lead wires 60 for taking out the detection signal of the sensor element 10 are drawn out.

  FIG. 2 is a perspective view showing the appearance of the sensor element 10. The sensor element 10 is formed with a flange 12 protruding (protruding) in the outer peripheral direction in the middle of the axis O direction. A bottomed portion 13 that is gradually reduced in diameter toward the distal end side and closed at the distal end portion is formed on the distal end side of the flange portion 12. In the present embodiment, the outer electrode 10 b is formed so as to cover a part of the outer surface of the bottomed portion 13. Further, the outer electrode 10b is covered with an electrode protective layer 14 for protecting the outer electrode 10b.

  In the sensor element 10, a substantially hollow cylindrical base portion 17 having a substantially constant outer diameter and an opening at the rear end is formed on the rear end side of the flange portion 12. In addition, external leads 10 c that are electrically connected to the outer electrode 10 b are provided on the outer surfaces of the flange portion 12 and the base portion 17. The external lead portion 10c of this embodiment is a vertical lead portion that extends linearly in the direction of the axis O from the rear end of the outer electrode 10b via the flange portion 12 to the rear end side of the flange portion 12. 15 and a ring lead portion 16 provided at the rear end portion of the vertical lead portion 15. The ring lead portion 16 extends to a part of the outer surface of the sensor element 10 along the outer periphery of the sensor element 10 in the base portion 17.

  As described above, the inner electrode 10 a is provided on the inner surface of the sensor element 10. A cylindrical hole 10d is formed inside the bottomed cylindrical solid electrolyte body 11 (see FIG. 1), and the inner electrode 10a is formed so as to cover the entire surface of the cylindrical hole 10d except for the vicinity of the rear end. ing.

The solid electrolyte body 11 included in the sensor element 10 can be composed of, for example, zirconium oxide (ZrO ₂ ) to which yttrium oxide (Y ₂ O ₃ ) is added, that is, yttria-stabilized zirconia. Alternatively, by other solid electrolyte such as stabilized zirconia to which an oxide selected from calcium oxide (CaO), magnesium oxide (MgO), cerium oxide (CeO ₂ ), aluminum oxide (Al ₂ O ₃ ) and the like is added. The sensor element 10 may be configured.

  The inner electrode 10a and the outer electrode 10b formed on the surface of the sensor element 10 are preferably formed of a noble metal or a noble metal alloy such as platinum (Pt) or a platinum alloy. The inner electrode 10a and the outer electrode 10b can be formed by a plating method such as electroless plating, for example. Further, when the solid electrolyte body 11 is manufactured by firing a molded body made of, for example, zirconia powder containing yttria, etc., the external lead portion 10c has a predetermined pattern using a noble metal paste on the outer surface of the molded body. The printing can be performed simultaneously with the firing of the molded body.

  Returning to FIG. 1, the sensor element 10 is assembled in the metal shell 20. The metal shell 20 is a metal member that is arranged so as to surround the middle part of the sensor element 10 in the axis O direction. On the inner surface of the metal shell 20, a step portion 20b whose inner diameter is reduced toward the distal end is provided. A packing 30 is disposed between the stepped portion 20b and the flange portion 12 of the sensor element 10. When the metal shell 20 and the sensor element 10 are assembled, the sensor element 10 is inserted into the metal shell 20 from the rear end side of the metal shell 20. Then, the flange portion 12 of the sensor element 10 is indirectly brought into contact with the step portion 20 b by applying the flange portion 12 to the packing 30.

  Further, a seal portion 31 filled with talc powder is disposed in the gap between the sensor element 10 and the flange 12 of the sensor element 10 in the gap between the sensor element 10 and the metal shell 20. The gap is sealed. A cylindrical insulating member (ceramic sleeve) 32 is disposed on the rear end side of the seal portion 31. Furthermore, a metal ring (stainless flat washer) 33 is disposed on the rear end side of the insulating member 32. On the rear end side of the metal ring 33, the rear end portion of the metal shell 20 is bent inward to form a crimped portion 20a. By forming the crimped portion 20a at the rear end portion of the metal shell 20, the insulating member 32 is pressed against the distal end side to crush the seal portion 31, and the insulating member 32 and the seal portion 31 are fixed by crimping. The gap between the sensor element 10 and the metal shell 20 is sealed.

  In the vicinity of the center of the metal shell 20, a polygonal flange portion 20c formed in a shape protruding radially outward is provided in order to engage a hexagon wrench or the like. A male screw portion 20d is formed on the outer surface between the flange portion 20c and the tip portion 20f that is the tip portion of the metal shell 20. The male screw portion 20d of the metal shell 20 is attached to, for example, a screw hole of an exhaust pipe of an automobile, and the tip of the sensor element 10 is exposed in the exhaust pipe, whereby oxygen in a gas to be detected (exhaust gas) using the gas sensor 100 is exposed. The concentration can be detected. In the gas sensor 100, a gasket for preventing gas escape when the gas sensor 100 is attached to the exhaust pipe is further fitted into the step between the front end surface of the flange portion 20 c and the rear end of the male screw portion 20 d (FIG. Not shown).

  A cylindrical protector 62 made of metal (such as stainless steel) is fixed to the distal end portion 20 f of the metallic shell 20, and the distal end of the sensor element 10 protruding from the metallic shell 20 is covered with the protector 62. The protector 62 has a plurality of holes for taking exhaust gas into the protector 62.

  On the other hand, a metallic outer tube 40 is joined to the rear end of the metal shell 20 to cover the rear end of the sensor element 10. The outer cylinder 40 can be formed of stainless steel such as SUS430, SUS304, SUS304L, SUS310S, SUS316, SUS316L, or the like. The outer cylinder 40 has a front end portion 40a connected to the metal shell 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.

  On the inner side of the distal end portion 40a of the outer cylinder 40, a substantially cylindrical and insulating separator 34 with a step is disposed. The separator 34 is formed with two insertion holes 34 a and 34 b that penetrate the separator 34 in the direction of the axis O. The plate-like base portion 71 of the first connection terminal 70 and the plate-like base portion 81 of the second connection terminal 80 are inserted through these insertion holes 34a and 34b, respectively. Here, the first connection terminal 70 and the second connection terminal 80 are members for connecting the inner electrode 10a or the outer electrode 10b and the lead wire 60, respectively. Connection end portions 72 and 82 are formed at the rear ends of the respective plate-like base portions 71 and 81, and different lead wires 60 are caulked and connected to the connection end portions 72 and 82, respectively. The first connection terminal 70 and the second connection terminal 80 can be formed of a conductive material, for example, a metal material selected from stainless steel, nickel alloy, copper, cobalt alloy, and the like. It is desirable to use a metal material that exhibits sufficient corrosion resistance in the environment in which the gas sensor 100 is used. The first connection terminal 70 corresponds to a “connection terminal” in the claims.

  The separator 34 has the rear end surface of the separator 34 in contact with the stepped portion 43 of the outer cylinder 40, and the front end surface of the separator 34 is in contact with the holding metal fitting 35 disposed on the front end side of the separator 34. It is held in the tube 40. The holding metal fitting 35 is disposed on the front end side of the separator 34 and is fixed in the outer cylinder 40 by crimping the front end portion 40 a of the outer cylinder 40.

  FIG. 3 is a perspective view illustrating an outline of the appearance of the first connection terminal 70. As described above, the first connection terminal 70 includes the connection end 72 to which the lead wire 60 is connected and the plate-like base 71 disposed in the insertion hole 34 a of the separator 34. A support arm 74 is formed at the center of the plate-like base 71 by forming a cut in a substantially U-shape and bending the inner part thereof toward the outer periphery. The support arm 74 supports the plate-like base 71 in the insertion hole 34a of the separator 34 so that the plate-like base 71 is substantially parallel to the axis O direction.

  Further, in the first connection terminal 70, a cylindrical portion 73 is provided on the distal end side with respect to the plate-like base portion 71. The cylindrical portion 73 has a slit 75 parallel to the direction of the axis O and can be elastically deformed in the radial direction, and the cylindrical portion 73 when the sensor element 10 is not fitted into the cylindrical hole 10d. Is larger than the inner diameter of the cylindrical hole 10 d of the sensor element 10. Therefore, the cylindrical part 73 and the inner electrode 10a can be brought into contact by inserting into the cylindrical hole 10d of the sensor element 10 while reducing the diameter of the cylindrical part 73.

  Further, a plurality of (two in FIG. 3) plate-like extending pieces 76 are provided at the tip of the cylindrical portion 73 so as to protrude further toward the tip side. The plurality of extending pieces 76 constitute an extending portion 79 as a whole. Each extending piece 76 has a bent portion 77 at the rear end portion in the vicinity of the connecting portion with the cylindrical portion 73. Due to the bent portion 77, the extending piece 76 is bent in its own plate thickness direction so as to approach the axis line (axis line O) of the sensor element 10. As a result, in the two extending pieces 76, the diameter of the circumscribed circle at the tip side of the bent portion 77 is smaller than the diameter of the inscribed circle of the cylindrical portion 73. Further, in the two extending pieces 76, the diameter of the circumscribed circle at the tip side of the bent portion 77 is smaller than the diameter of the inscribed circle at the opening of the cylindrical hole 10 d provided in the sensor element 10. Yes.

  In the vicinity of the distal ends of the two extending pieces 76, a distal end connecting portion 78 for connecting the extending pieces 76 to each other is provided. The distal end connecting portion 78 is formed as a folded portion having a shape folded so as to approach the axis (axis O) of the sensor element 10 while connecting the vicinity of the distal ends of the two extending pieces 76. The tip connection portion 78 can also be called a tip fixing portion that fixes the vicinity of the tips of the two extending pieces 76. In this way, by fixing the vicinity of the ends of the two extending pieces 76, the rigidity of the extending portion 79, particularly the rigidity of the portion in the vicinity of the leading end of the extending portion 79 can be increased. Therefore, the tip connection part 78 can also be called a rigidity imparting part. Such a structure related to the extending portion 79 is a structure for facilitating the operation of fitting the distal end side of the first connection terminal 70 into the cylindrical hole 10 d of the sensor element 10. The operation of fitting the first connection terminal 70 into the sensor element 10 will be described in detail later.

  FIG. 4 is a plan view showing a schematic shape of a plate-like member for forming the first connection terminal 70. The first connection terminal 70 can be produced, for example, by punching a flat plate member to form a plate member having the shape shown in FIG. 4 and bending the plate member.

  FIG. 5 is a perspective view showing the appearance of the second connection terminal 80. As described above, the second connection terminal 80 includes the connection end portion 82 to which the lead wire 60 is connected and the plate-like base portion 81 disposed in the insertion hole 34 b of the separator 34. A support arm 84 is formed at the center of the plate-like base 81 by forming a cut in a substantially U-shape and bending the inner part thereof toward the outer peripheral side. The support arm 84 supports the plate-like base 81 in the insertion hole 34b of the separator 34 so that the plate-like base 81 is substantially parallel to the axis O direction.

  Further, in the second connection terminal 80, a cylindrical portion 83 is provided on the tip side of the plate-like base portion 81. The tubular portion 83 is electrically connected to the outer electrode 10b by being fitted on the outer surface of the rear end portion of the sensor element 10. More specifically, the cylindrical portion 83 is formed in a substantially hollow cylindrical shape obtained by bending a substantially rectangular plate, and has a slit 85 parallel to the axis O direction. The cylindrical portion 83 can be elastically deformed in the radial direction by expanding and contracting the width of the slit 85. The inner diameter of the cylindrical portion 83 when not fitted into the outer surface of the rear end portion of the sensor element 10 is smaller than the outer diameter of the rear end portion of the sensor element 10. The cylindrical portion 83 can be fitted into the sensor element 10 by widening the slit 85.

  A plurality of flare pieces 86 project from the tip of the cylindrical portion 83 along the circumference that forms the tip of the cylindrical portion 83. Each flare piece 86 is bent toward the outer peripheral side at the connection portion with the tip of the cylindrical portion 83, and the entire plurality of flare pieces 86 spread radially from the tip of the cylindrical portion 83. Therefore, assuming a circle in contact with the inner surfaces of the plurality of flare pieces 86, the diameter of the contacting circle becomes larger at the tip of the flare piece 86. That is, the inner diameters of the plurality of flare pieces are larger toward the front end side, and the inscribed circle at the front end of the flare piece 86 is larger than the outer diameter of the rear end of the sensor element 10. The plurality of flare pieces 86 have a structure for facilitating the operation of fitting the tubular portion 83 into the rear end portion of the sensor element 10. The operation of fitting the tubular portion 83 into the sensor element 10 will be described in detail later.

  Returning to FIG. 1, a substantially columnar grommet 36 is inserted and fixed by caulking inside the rear end portion 40 b of the outer cylinder 40 of the gas sensor 100. The grommet 36 is formed with two insertion holes penetrating the grommet 36 in the direction of the axis O, and the lead wire 60 is drawn out from each of the two insertion holes. The rear end side of the grommet 36 is expanded in a flange shape. The grommet 36 is positioned by inserting the grommet 36 from the rear end of the outer cylinder 40 into the outer cylinder 40 and bringing the above-mentioned enlarged diameter portion into contact with the rear end of the outer cylinder 40. The grommet 36 can be formed of a rubber material such as silicon rubber or fluorine rubber, for example.

  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 tip side than the grommet 36. It is open. An annular air-permeable filter 37 is covered on the radially outer side of the rear end portion 40b of the outer cylinder 40 so as to cover the first ventilation hole 41. Further, the filter 37 is made of a metal cylinder from the radially outer side. A protective outer cylinder 38 is enclosed. The protective outer cylinder 38 can be formed of stainless steel such as SUS430, SUS304, SUS304L, SUS310S, SUS316, SUS316L, or the like. Four second vent holes 39 (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 38 so that outside air can be introduced into the outer cylinder 40 through the filter 37. It has become. The filter 37 is held between the outer cylinder 40 and the protective outer cylinder 38 by crimping the outer cylinder 40 and the protective outer cylinder 38 at the front end side and the rear end side of the second vent hole 39. The filter 37 can be constituted by a porous structure of a water repellent resin such as a fluorine-based resin, and has a water repellency, so that the reference gas (in the internal space of the sensor element 10 does not pass through outside water). Air) can be introduced.

  The protective outer cylinder 38 is bent radially inward so that the rear end portion is provided on the rear end surface of the grommet 36, and an opening 63 is formed in the center of the rear end portion. 60 is pulled out. Further, the rear end side of the protective outer cylinder 38 is caulked and fixed to a caulking portion provided at the rear end portion 40 b of the outer cylinder 40. That is, the grommet 36 is disposed in the outer cylinder 40 by simultaneously caulking both the protective outer cylinder 38 and the outer cylinder 40.

  FIG. 6 is an explanatory diagram showing an outline of assembly of the gas sensor 100. When assembling the gas sensor 100, the rear end side assembly A having the rear end side structure of the gas sensor 100 and the front end side assembly B having the front end side structure are assembled, and the assemblies A and B are assembled. In FIG. 6, the assembling operation for placing the assembly A on the rear end of the assembly B is shown by a cross-sectional view.

  When manufacturing the gas sensor 100, first, the front end side assembly B is assembled. Specifically, the sensor element 10 is inserted into the metal shell 20 from the rear end side of the metal shell 20, and the sensor element 10 is disposed on the packing 30 disposed in the metal shell 20. Thereby, the collar part 12 of the sensor element 10 is made to contact | abut indirectly to the step part 20b. Thereafter, the cylindrical seal portion 31 is disposed in the gap between the metal shell 20 and the sensor element 10, and the insulating member 32 and the metal ring 33 are sequentially disposed on the seal portion 31. Then, by bending the rear end side of the metal shell 20 inward to form the crimped portion 20a, the insulating member 32 is pressed against the distal end side to crush the seal portion 31, and the insulating member 32 and the seal portion 31 are It is fixed by crimping. In this way, assembly B is produced.

  On the other hand, the rear end side assembly A is assembled. That is, the separator 34 assembled with the first connection terminal 70 and the second connection terminal 80 is arranged together with the grommet 36 in the outer cylinder 40 to assemble the assembly A. Specifically, the first connection terminal 70 and the second connection terminal 80 connected to the lead wire 60 are inserted into the insertion holes 34 a and 34 b of the separator 34, and then the separator 34 is inserted into the step portion 43 of the outer cylinder 40. Abut. Thereafter, the holding metal fitting 35 is inserted into the gap between the separator 34 and the outer cylinder 40, and the distal end portion 40 a of the outer cylinder 40 is caulked to fix the holding metal fitting 35. Further, the grommet 36 is inserted from the rear end of the outer cylinder 40, and the filter 37 and the protective outer cylinder 38 are disposed at the rear end portion 40b of the outer cylinder 40, respectively, and the filter 37 and the grommet 36 are fixed by crimping. Assembly A is made.

  Then, the gas sensor 100 is assembled by aligning the axes of the assembly A and the assembly B and covering the front end of the outer cylinder 40 of the assembly A over the rear end of the metal shell 20 of the assembly B.

  As shown in FIG. 6, in the rear end side assembly A, the distal end portion of the extending piece 76 of the first connection terminal 70 projects from the distal end of the outer cylinder 40 to the distal end side. Here, the cylindrical portion 73 of the first connection terminal 70 is located on the rear end side with respect to the front end of the outer cylinder 40 and is accommodated in the rear end side assembly A. In the front end side assembly B, the rear end portion of the sensor element 10 protrudes from the rear end of the metal shell 20. When assembling the assembly A and the assembly B, first, the extension piece 76 protruding from the assembly A is inserted into the cylindrical hole 10d formed in the sensor element 10 of the assembly B, and the distal end portion of the outer cylinder 40 is inserted. Is put on the rear end of the metal shell 20.

  Here, as described above, the extending piece 76 has the bent portion 77 at the rear end, and the diameter of the circumscribed circle of the two extending pieces 76 is inscribed in the cylindrical hole 10d of the sensor element 10. It is smaller than the diameter of the circle. Further, a tip connecting portion 78 is provided in the vicinity of the tips of the two extending pieces 76, and the rigidity of the entire extending piece 76 is enhanced. Therefore, the extending piece 76 has a property that is difficult to deform. Yes. When the first connection terminal 70 is inserted into the cylindrical hole 10d, the outer surface of the bent portion 77 of the first connection terminal 70 eventually comes into contact with the inner surface of the cylindrical hole 10d, and the first connection terminal 70 is further pushed in. The first connection terminal 70 and the inner electrode 10a are electrically connected.

  Moreover, when the front-end | tip part of the outer cylinder 40 is covered on the rear-end part of the metal shell 20 as mentioned above, it protrudes from the front-end | tip of the cylindrical part 83 of the 2nd connection terminal 80 with which the assembly A is equipped inside the assemblies A and B. The flare piece 86 provided in this manner contacts the rear end of the sensor element 10. Thereafter, when the assembly A and the assembly B are further fitted, the rear end of the sensor element 10 is guided into the cylindrical portion 83 by the inner surface of each flare piece 86 and pushes the cylindrical portion 83 from the inside. spread. At this time, the cylindrical part 83 expands a diameter by expanding the slit 85 (FIG. 5). As described above, when the tubular portion 83 is fitted into the rear end portion of the sensor element 10, the inner surface of the tubular portion 83 is in contact with the ring lead portion 16 (see FIG. 2), so that the second connection terminal 80 and the outside are connected. The electrode 10b is electrically connected.

  As described above, when the fitting of the assembly A and the assembly B is finished, the outer surface of the cylindrical portion 73 of the first connection terminal 70 is in contact with the inner electrode 10a. Further, the inner surface of the cylindrical portion 83 of the second connection terminal 80 and the ring lead portion 16 of the sensor element 10 come into contact with each other, and the tip of each flare piece 86 is separated from the rear end of the metal shell 20 while It reaches near the rear end of the metal fitting 20. In order to make the positional relationship between the first connection terminal 70 or the second connection terminal 80 and the sensor element 10 as desired, the sensor element 10, the first connection terminal 70, and the second connection terminal in each assembly. The assembly position of 80 and the assembly position between the assembly A and the assembly B may be set in advance according to the desired degree of overlap.

  After assembling the assemblies A and B so that the outer cylinder 40 covers up to a predetermined position of the metal shell 20, the outer peripheral surface of the front end portion of the outer cylinder 40 is subjected to the rear end portion of the metal shell 20 by laser welding or the like. By connecting to the gas sensor 100, the gas sensor 100 is obtained.

  According to the gas sensor 100 of the present embodiment configured as described above, the first connection terminal 70 includes the extending portion 79 that extends until reaching the position on the distal end side further than the distal end of the outer cylinder 40. Yes. Therefore, when the gas sensor 100 is assembled, the extending portion 79 can be used as a guide for the operation of inserting the first connection terminal 70 into the cylindrical hole 10 d of the sensor element 10. Therefore, the tubular portion 73 of the first connection terminal 70 housed in the rear end side assembly A can be easily fitted into the tubular hole 10d. Thus, the assembly operation of the gas sensor 100 that does not have a heater can be facilitated.

  In the present embodiment, the extension piece 76 of the first connection terminal 70 is arranged in the thickness direction of the first connection terminal 70 so as to approach the axis O of the sensor element 10 at the rear end portion in the vicinity of the connection portion with the cylindrical portion 73. It has a bent portion 77 that bends. Therefore, when the extended piece 76 is inserted into the cylindrical hole 10d, it is possible to ensure a longer distance in the direction perpendicular to the axis O between the distal end portion of the extended piece 76 and the inner wall of the cylindrical hole 10d. It becomes possible. Therefore, it is possible to prevent the inner electrode 10a from being damaged by the distal end portion of the extending piece 76 when the gas sensor 100 is assembled.

  Here, in the present embodiment, the sensor element 10 is formed thinner toward the tip, and the inner diameter (diameter of the cross section perpendicular to the axis O) of the cylindrical hole 10d of the sensor element 10 is shorter toward the tip side. Therefore, when the first connection terminal 70 is fitted into the sensor element 10, the amount of bending at the bent portion 77 of the extending piece 76 is set so that the extending piece 76 is separated from the inner electrode 10a to the tip. It is desirable to do so (see FIG. 1). Thereby, the effect which suppresses the damage of the inner side electrode 10a resulting from providing the extended piece 76 can be heightened. The extension piece 76 may have a length that protrudes from the outer cylinder 40 when the gas sensor 100 is assembled, and the bending amount of the bent portion 77 is such that the tip of the extension piece 76 is separated from the inner electrode 10a during assembly. The length of the extension piece 76 may be set in consideration of the balance with the above.

  In the present embodiment, the first connection terminal 70 has a cylindrical portion 73 on the rear end side of the extension piece 76, and the cylindrical portion 73 is not fitted into the cylindrical hole 10 d of the sensor element 10. The inner diameter of the sensor element 10 is larger than the inner diameter of the cylindrical hole 10 d of the sensor element 10. Therefore, by electrically fitting the first connection terminal 70 into the sensor element 10 while being guided by the extension piece 76, it is possible to easily ensure the electrical connection between the first connection terminal 70 and the inner electrode 10a. .

  When the gas sensor 100 is assembled, the extending piece 76 is bent inward, so that the first connection terminal 70 and the sensor element are not in contact until the cylindrical portion 73 contacts the inner wall of the cylindrical hole 10d of the sensor element 10. There is almost no contact with 10. Thus, until the first connection terminal 70 and the sensor element 10 come into contact with each other, no resistance is generated between the first connection terminal 70 and the sensor element 10, and therefore the operation of inserting the first connection terminal 70 is performed with a low load. Can be done. Therefore, the load at the time of insertion is transmitted to the structure from the outer cylinder 40 to the first connection terminal 70, and the structure of the separator 34, the holding bracket 35, the outer cylinder 40, etc. supported by the plate-like base 71 of the first connection terminal 70. It is possible to suppress damage due to the load applied to the

  Furthermore, in the present embodiment, a tip connecting portion 78 that connects the vicinity of the tips of the two extending pieces 76 is provided, and the rigidity of the entire extending portion 79 is increased. Therefore, when the gas sensor 100 is assembled, it is possible to suppress deformation of the extending piece 76 that is an elongated thin plate shape. By suppressing the deformation of the extending portion 79, it is possible to easily handle the first connection terminal 70 in the middle of manufacturing, and it is possible to suppress problems such as an undesired deformation of the extending portion 79 during manufacturing and a defective product. . Moreover, it can suppress that the extension part 79 contacts the inner side electrode 10a by suppressing a deformation | transformation of the extension part 79. FIG. Therefore, damage to the inner electrode 10a when the gas sensor 100 is assembled can be suppressed.

  The tip connecting portion 78 has a shape folded so as to approach the axis (axis O) of the sensor element 10 while connecting the vicinity of the tips of the two extending pieces 76. Therefore, it can suppress that the front-end | tip connection part 78 protrudes to the radial direction outer side from the extension part 79, and can suppress that the front-end | tip connection part 78 damages the inner side electrode 10a at the time of the assembly of the gas sensor 100. The amount of folding of the tip connection portion 78 may be set so that the contact of the tip connection portion 78 with the inner electrode 10a can be sufficiently suppressed. For example, it is desirable to fold the tip connecting portion 78 so that the tip connecting portion 78 is inside the inscribed circle of the extending portion 79.

  Furthermore, in this embodiment, since the 1st connection terminal 70 is manufactured by bending one plate-shaped member shown in FIG. 4, a manufacturing process can be simplified. That is, the tip connection portion 78 can be formed simultaneously with the bending process for forming the first connection terminal 70, and therefore the tip connection portion 78 can be formed without complicating the manufacturing process. In addition, since the bent portion 77 can be formed at the same time as the bending process for forming the first connection terminal 70, in order to form the extended portion 79 having a smaller inscribed circle than the cylindrical portion 73, for example, a drawing process is performed. There is no need to employ such a complicated process.

B. Second embodiment:
FIG. 7 is a perspective view illustrating an outline of the appearance of the first connection terminal 170 provided in the gas sensor according to the second embodiment. The gas sensor of the second embodiment has the same configuration as that of the gas sensor of the first embodiment except that the gas sensor of the second embodiment includes a first connection terminal 170 instead of the first connection terminal 70, and thus is common to the first embodiment. Parts are denoted by the same reference numerals, and detailed description is omitted.

  The first connection terminal 170 is provided with an extension portion 179 including two extension pieces 176 instead of the extension portion 79. In addition, the first connection terminal 170 is not provided with the tip connection portion 78, and each extension piece 176 is formed with a bent portion 178.

  The bent portion 178 bends a part of the extended piece 176 from the vicinity of the boundary with the bent portion 77 to the tip at a fold line parallel to the extending direction (axis O direction) in each extended piece 176. It is formed by. The bending direction is a direction in which a bent portion 178 formed by bending approaches the axis O. The angle of bending with respect to the plate thickness direction of the extending piece 176 is not particularly limited. For example, the cross section of the extension piece 176 may be L-shaped with a substantially right angle, and the cross section of the extension piece 176 may have a dogleg shape with an obtuse or acute angle. The folding line portion may be a curved surface, and the cross section of the extending piece 176 may be a semicircular circumferential shape, for example. The direction of bending may be opposite to that in FIG. 7, but it is preferable to bend in the direction of FIG. 7 because the bent portion 178 is less likely to contact the inner electrode 10a. Such a bent portion 178 can be formed, for example, by bending the extending piece 176. In the extending piece 176, the plate thickness direction refers to the plate thickness of the portion facing the inner wall surface of the cylindrical hole 10d other than the bent portion 178.

  According to the second embodiment, since the bent portion 178 is provided in the extended piece 176, the rigidity of each extended piece 176 and the extended portion 179 as a whole can be increased. Therefore, when the gas sensor 100 is assembled, it is possible to suppress deformation of the extending piece 176 that is an elongated thin plate shape. By suppressing the deformation of the extension part 179, the first connection terminal 170 during the manufacture can be easily handled, and problems such as an undesirable deformation of the extension part 179 during manufacture can be suppressed. . Moreover, it can suppress that the extension part 179 contacts the inner side electrode 10a by suppressing a deformation | transformation of the extension part 179. FIG. Therefore, damage to the inner electrode 10a when the gas sensor 100 is assembled can be suppressed.

C. Third embodiment:
FIG. 8 is a perspective view showing an outline of the appearance of the first connection terminal 270 provided in the gas sensor of the third embodiment. The gas sensor of the third embodiment has the same configuration as that of the gas sensor of the first embodiment except that the gas sensor of the third embodiment is provided with the first connection terminal 270 instead of the first connection terminal 70, and thus is common to the first embodiment. Parts are denoted by the same reference numerals, and detailed description is omitted.

  The first connection terminal 270 is provided with an extension part 279 including two extension pieces 276 instead of the extension part 79. Further, the first connection terminal 270 is not provided with the tip connection portion 78, and the protruding strip 278 is formed on each extending piece 276. The protruding portion 278 is provided in each extending piece 276 so as to extend in a direction parallel to the extending direction (axis O direction) and to protrude toward the axis O (concave on the back side). It is the linear convex part made. Such a protrusion 278 can be formed by, for example, pressing the extending piece 276.

  According to the third embodiment, since the protruding strip 278 is provided on the extended piece 276, the rigidity of each extended piece 276 and the extended portion 279 as a whole can be increased. Therefore, when the gas sensor 100 is assembled, deformation of the extending piece 276 that is an elongated thin plate shape can be suppressed. By suppressing the deformation of the extension part 279, the first connection terminal 270 in the middle of manufacture can be easily handled, and problems such as an undesired deformation of the extension part 279 during manufacture can be suppressed. . Moreover, it can suppress that the extension part 279 contacts the inner side electrode 10a by suppressing a deformation | transformation of the extension part 279. FIG. Therefore, damage to the inner electrode 10a when the gas sensor 100 is assembled can be suppressed.

  In the third embodiment, the ridges 278 are formed so as to protrude toward the axis O, but may be formed so as to protrude toward the side away from the axis O. In any case, the effect of increasing the rigidity of the extending portion 279 can be obtained. However, it is desirable to make the projection closer to the axis O because the projection 278 is less likely to contact the inner electrode 10a.

  Further, in FIG. 8, in each extending piece 276, the protrusion 278 is formed so as to extend from the vicinity of the boundary with the bent portion 77 to the vicinity of the tip of the extending piece 276, but may have a different configuration. For example, the ridge portion 278 may be provided so as to extend from the extending piece 276 to the cylindrical portion 73 across the bent portion 77. With such a configuration, the strength of the region including the connecting portion between the extending piece 276 and the cylindrical portion 73 can be increased, and the effect of suppressing deformation of the extending piece 276 can be increased.

D. Fourth embodiment:
FIG. 9 is a perspective view illustrating an outline of the appearance of the first connection terminal 370 included in the gas sensor according to the fourth embodiment. The gas sensor of the fourth embodiment has the same configuration as that of the gas sensor of the first embodiment except that the gas sensor of the fourth embodiment is provided with a first connection terminal 370 instead of the first connection terminal 70, and thus is common to the first embodiment. Parts are denoted by the same reference numerals, and detailed description is omitted.

  The first connection terminal 370 is provided with an extension portion 379 including two extension pieces 376 instead of the extension portion 79. Further, the first connection terminal 370 is not provided with the tip connection part 78, and the reinforcing part 378 is formed on each extending piece 376. The reinforcing portion 378 is a member that is fixed on one surface of each extending piece 376 and has a shape that is narrower than the extending piece 376 and extends parallel to the axis O direction. The constituent material of the reinforcing portion 378 and the fixing method of the reinforcing portion 378 are not particularly limited, and may be sufficient to withstand the usage environment of the gas sensor 100. For example, the reinforcing portion 378 can be formed by welding a metal member onto the extending piece 376.

  According to the fourth embodiment, since the extending portion 376 is provided with the reinforcing portion 378, the rigidity of each extending piece 376 and the extending portion 379 as a whole can be increased. Therefore, when the gas sensor 100 is assembled, it is possible to suppress deformation of the extending piece 376 that is an elongated thin plate shape. By suppressing the deformation of the extension part 379, the handling of the first connection terminal 370 during manufacture can be facilitated, and problems such as an undesired deformation of the extension part 379 during manufacture can be suppressed. . Moreover, it can suppress that the extension part 379 contacts the inner side electrode 10a by suppressing a deformation | transformation of the extension part 379. FIG. Therefore, damage to the inner electrode 10a when the gas sensor 100 is assembled can be suppressed.

  In the fourth embodiment, the reinforcing portion 378 is formed on the surface facing the inner electrode 10a in the extending piece 376, but may be formed on the back surface of the surface facing the inner electrode 10a. From the viewpoint of making it difficult for the reinforcing portion 378 to come into contact with the inner electrode 10a, it is preferable to form the reinforcing portion 378 on the back side surface. However, in order to increase the rigidity of the extending portion 379, the reinforcing portion 378 may be fixed on at least one surface of the extending piece 376.

  Further, in the fourth embodiment, as shown in FIG. 9, the reinforcing portion 378 is provided so as to extend from the extending piece 376 to the cylindrical portion 73 across the bent portion 77. The strength of the connecting portion between the piece 376 and the cylindrical portion 73 can be increased, and the effect of suppressing deformation of the extending piece 376 can be enhanced. However, the reinforcing portion 378 may be provided only on the extending piece 376 and not provided on the cylindrical portion 73 side.

E. Fifth embodiment:
FIG. 10 is a perspective view illustrating an outline of the appearance of the first connection terminal 470 included in the gas sensor of the fifth embodiment. Since the gas sensor of the fifth embodiment has the same configuration as the gas sensor of the first embodiment except that the first connection terminal 470 is provided instead of the first connection terminal 70, the gas sensor is common to the first embodiment. Parts are denoted by the same reference numerals, and detailed description is omitted.

  The first connection terminal 470 is provided with an extension portion 479 including two extension pieces 476 instead of the extension portion 79. The first connection terminal 470 is not provided with the tip connection portion 78, and the tip ends of the two extending pieces 476 are fixed to form the tip fixing portion 478. The method for fixing the tip of the extension piece 476 is not particularly limited, as long as it can withstand the usage environment of the gas sensor 100. For example, the tip fixing portion 478 can be formed by welding the tip portions of the two extending pieces 476.

  According to the fifth embodiment, since the tip fixing portion 478 is provided on the first connection terminal 470, the rigidity of the extending portion 479 can be increased. Therefore, when the gas sensor 100 is assembled, it is possible to suppress deformation of the extending piece 476 that is an elongated thin plate shape. By suppressing the deformation of the extension part 479, the first connection terminal 470 during the manufacture can be easily handled, and problems such as the extension part 479 being undesirably deformed and being defective during the manufacture can be suppressed. . Moreover, it can suppress that the extension part 479 contacts the inner side electrode 10a by suppressing a deformation | transformation of the extension part 479. FIG. Therefore, damage to the inner electrode 10a when the gas sensor 100 is assembled can be suppressed.

  In the fifth embodiment, the bent portion 77 similar to that in the first to fourth embodiments is provided, but a different configuration may be used. For example, instead of providing a special step serving as the bent portion 77 only in the vicinity of the boundary between the extended piece 476 and the cylindrical portion 73, the distal end fixing portion 478 extends from the boundary with the cylindrical portion 73 in the extended piece 476. The entire region up to may be a bent portion.

  In the second to fifth embodiments, as in the first embodiment, the effect of facilitating the assembly of the gas sensor 100 by providing the extending portion, and the inner electrode 10a by providing the bent portion. The effect which can ensure the distance between the extension parts can be acquired. Further, if the first connection terminal is manufactured using a plate-like member as shown in FIG. 4 (however, a member that does not have a portion corresponding to the tip connection portion 78), the same effect that simplifies the manufacturing process is obtained. can get.

  In the first embodiment, the tip connection portion 78 is provided near the tips of the two extending pieces 76. In the second embodiment, the bent portion 178 is provided in each extending piece 176 from the vicinity of the boundary with the bent portion 77 to the tip of the extending piece 176. In the third embodiment, the ridge portion 278 is provided in each extending piece 276 from the vicinity of the boundary with the bent portion 77 to the vicinity of the tip of the extending piece 276. In the fourth embodiment, the reinforcing portion 378 is provided across the bent portion from the cylindrical portion 73 to the vicinity of the tip of each extending piece 376. In the fifth embodiment, the tip fixing portion 478 is provided in a region including the tip of the extending portion 479. As shown in FIGS. 7 and 10, these rigidity imparting portions are provided so as to include the distal end of the extended piece, thereby increasing the rigidity (strength) to the distal end of the extended piece and suppressing deformation. it can. However, as shown in FIGS. 3, 8, and 9, the position where these rigidity imparting portions are provided is effective in increasing the rigidity of the entire extending portion even if it is slightly separated from the tip of the extending piece. Can be obtained. However, when the rigidity imparting portion is provided apart from the distal end of the extended piece, even if the portion on the distal end side with respect to the rigidity imparted portion in the extended piece is deformed, the distal end of the deformed extended piece is the cylinder hole 10d. It is desirable to provide a rigidity imparting portion at a position that does not contact the inner electrode 10a. In the present application, the fact that the rigidity imparting portion is provided up to the tip of the extension piece is separated from the tip of the extension piece within a range in which contact of the extension piece to the inner electrode 10a can be suppressed as described above. Including cases.

F. Variations:
F1. Modification 1:
In the first to fifth embodiments, the extending portion includes two extending pieces, but may include one or three or more extending pieces. When there is one extending piece, a configuration that does not involve fixing of the extending pieces may be applied. Moreover, you may employ | adopt the structure different from the structure provided with one or several extension piece for an extension part. For example, the extending portion may be formed in a shape other than a plate shape. The extending part extends from a part of the tip of the cylindrical part to a position further to the tip side than the tip of the outer cylinder, and at the rear end part in the vicinity of the connecting part with the cylindrical part, If it has a bent portion that bends so as to approach the axis, the same effect of facilitating the assembly operation while suppressing damage to the inner electrode can be obtained.

F2. Modification 2:
Moreover, you may comprise the rigidity provision part provided in a 1st connection terminal combining the structure demonstrated in 1st-5th embodiment in multiple numbers. For example, a tip connection portion (see FIG. 3) for connecting the extension pieces to each other in the vicinity of the tip of the extension portion may be provided, and a protruding strip portion 278 (see FIG. 8) may be provided on each extension piece. Good. Alternatively, a reinforcing portion (see FIG. 9) is provided so as to extend from the region on the rear end side of each extending piece to the tubular portion across the bent portion of each extending piece, and the extending portion A tip connecting portion (see FIG. 3) for connecting the extended pieces may be provided in the vicinity of the tip. By combining a plurality of configurations, the effect of imparting rigidity to the extension portion can be enhanced, or the effect of suppressing deformation of the extension portion can be adjusted.

F3. Modification 3:
In the first to fifth embodiments, the connection terminal includes the rigidity imparting portion. However, the connection terminal may not include the rigidity imparting portion. If the connection terminal connected to the inner electrode includes an extended portion having a bent portion, the same effect that facilitates the assembling operation while suppressing damage to the inner electrode can be obtained.

F4. Modification 4:
In the first to fifth embodiments, the gas sensor is an oxygen concentration sensor, but may have a different configuration. The present invention is a sensor having a concentration cell having a pair of electrodes laminated on both surfaces of a solid electrolyte having ion conductivity and generating an electromotive force due to a concentration difference (partial pressure difference) of a specific gas component on each electrode. The same effect can be obtained by applying.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Sensor element 10a ... Inner electrode 10b ... Outer electrode 10c ... External lead part 10d ... Cylindrical hole 11 ... Solid electrolyte body 12 ... Gutter part 13 ... Bottom part 14 ... Electrode protective layer 15 ... Vertical lead part 16 ... Ring lead part 17 ... Base part 20 ... Metal fitting 20a ... Casting part 20b ... Step part 20c ... Hard part 20d ... Male thread part 20f ... Tip part 30 ... Packing 31 ... Seal part 32 ... Insulating member 33 ... Metal ring 34 ... Separators 34a, 34b ... Insertion hole 35 ... Holding metal fitting 36 ... Grommet 37 ... Filter 38 ... Protective outer cylinder 39 ... Second vent hole 40 ... Outer cylinder 40a ... Front end part 40b ... Rear end part 41 ... First vent hole 43 ... Step part 60 ... Lead wire 62 ... protector 63 ... opening 70, 170, 270, 370, 470 ... first connection terminal 71 ... plate-like base 72 ... connection end 73 ... cylindrical part 74 ... Holding arm 75 ... Slit 76, 176, 276, 376, 476 ... Extension piece 77 ... Bending part 78 ... Tip connection part 79, 179, 279, 379, 479 ... Extension part 80 ... Second connection terminal 81 ... Plate shape Base part 82 ... Connection end part 83 ... Cylindrical part 84 ... Support arm 85 ... Slit 86 ... Flare piece 100 ... Gas sensor 178 ... Bending part 278 ... Projection ridge part 378 ... Reinforcement part 478 ... Tip fixing part

Claims (10)

A sensor element comprising: a solid electrolyte body made of a solid electrolyte formed in a bottomed cylindrical shape with a bottom extending on the tip side in the axial direction; and an inner electrode provided on the inner surface of the solid electrolyte body;
A lead wire for taking out a detection signal of the sensor element;
A cylindrical portion that is elastically deformable in a radial direction and is inserted into the sensor element and contacts the inner electrode, and electrically connects the inner electrode and the lead wire via the cylindrical portion. A connection terminal;
A metal shell surrounding the sensor element;
An outer cylinder disposed on the rear end side of the metal shell and surrounding the connection terminal;
In a gas sensor comprising:
The cylindrical part is located on the rear end side with respect to the front end of the outer cylinder,
The connection terminal extends from a part of the tip of the cylindrical part to reach a position on the tip side further than the tip of the outer cylinder, and is a plate-like extension inserted into the cylinder hole of the sensor element. Equipped with a branch,
The extending portion has a bent portion that bends in the direction of its own thickness so as to approach the axis of the sensor element at the rear end portion in the vicinity of the connecting portion with the cylindrical portion, and is more distal than the bent portion. The part is spaced apart from the inner surface of the sensor element. The gas sensor according to claim 1,
The gas sensor according to claim 1, wherein the connection terminal includes a rigidity imparting portion that is provided apart from an inner surface of the sensor element and increases the rigidity of the extension portion. The gas sensor according to claim 2,
The connection terminal includes, as the extension part, a plurality of extension pieces extending from a part of the tip of the cylindrical part to a position closer to the tip side than the tip of the outer cylinder,
The gas sensor according to claim 1, wherein the rigidity imparting portion is a tip fixing portion that fixes the vicinity of the tips of the plurality of extending pieces. The gas sensor according to claim 3,
The gas sensor according to claim 1, wherein the tip fixing portion includes a tip connecting portion that is provided between the adjacent extending pieces and connects the vicinity of the leading ends of the adjacent extending pieces. The gas sensor according to claim 4, wherein
The gas sensor according to claim 1, wherein the tip connection portion includes a folded portion that is folded so as to approach the axis of the sensor element. The gas sensor according to claim 2,
The connection terminal includes, as the extension part, one or a plurality of extension pieces extending from a part of the tip of the cylindrical part to a position closer to the tip than the tip of the outer cylinder,
The gas sensor according to claim 1, wherein the rigidity imparting portion is a concave portion or a convex portion provided in each of the extending pieces. The gas sensor according to claim 2,
The connection terminal includes, as the extension part, one or a plurality of extension pieces extending from a part of the tip of the cylindrical part to a position closer to the tip than the tip of the outer cylinder,
The gas sensor according to claim 1, wherein the rigidity imparting portion is a reinforcing portion fixed on at least one surface of each of the extending pieces. The gas sensor according to claim 2,
The connection terminal includes, as the extension part, one or a plurality of extension pieces extending from a part of the tip of the cylindrical part to a position closer to the tip than the tip of the outer cylinder,
The gas sensor according to claim 1, wherein the rigidity imparting portion is a bent portion obtained by bending each extending piece along an axial direction. The gas sensor according to claim 6 or 7,
The rigidity imparting portion straddles the bent portion of each extension piece from each extension piece to a position on the rear end side of the connection portion between each extension piece and the tubular portion. A gas sensor characterized by being provided. A gas sensor according to any one of claims 6 to 9,
The said rigidity provision part is provided in each said extension piece so that it may extend in an axial direction to the front-end | tip of the said extension piece. The gas sensor characterized by the above-mentioned.

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