JP5432209B2 - Gas sensor - Google Patents

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, a configuration is known in which a cylindrical gas sensor element extending in the axial direction is held around the radial direction by a metal shell, and an outer cylinder is attached to the rear end of the metal shell (Patent Document 1).
This gas sensor 1000 is manufactured as shown in FIG. First, the sensor element assembly B is assembled while holding the gas sensor element 300 inside the metal shell 200. Specifically, the gas sensor element 300 is disposed on a ceramic holder 170 disposed in the metal shell 200. Thereafter, a talc 600 is filled in the gap between the metal shell 200 and the gas sensor element 300, the ceramic sleeve 310 and the metal packing 320 are sequentially disposed on the talc 600, and the rear end side of the metal shell 200 is crimped to detect the sensor. The element assembly B is assembled. On the other hand, the separator 1110 in which the inner terminal 710 on the inner side and the outer terminal 910 on the outer side are assembled together with the grommet 131 in the outer cylinder 400 and the separator assembly A is assembled. Specifically, the inner terminal 710 and the outer terminal 910 connected to the lead wire 41 are inserted into the insertion holes 1115 and 1116 of the separator 1110, and then the separator 1110 is brought into contact with the step portion 410 of the outer cylinder 400. Thereafter, the holding metal fitting 800 is inserted into the gap between the separator 1110 and the outer cylinder 400, the grommet 131 is disposed on the rear end side of the outer cylinder 400, and the separator assembly A is assembled. Note that the heater 15 is already attached to the inner terminal 710. Then, when the axis lines of the separator assembly A and the element assembly B are aligned and the separator assembly A is put on the rear end of the sensor element assembly B, the heater 15 is inserted into the gas sensor element 300 and the inner electrodes of the sensor element 300 and Outer electrodes (not shown) are electrically connected to the inner terminal 710 and the outer terminal 910, respectively. Thereafter, the outer cylinder 400, the outer peripheral part of the holding fitting 800, the outer peripheral part of the grommet 131, and the overlapping part with the metallic shell 200 are respectively crimped, and the overlapping part between the outer cylinder 400 and the metallic fitting 200 is laser welded or the like. The outer cylinder 400 is connected to the rear end of the metal shell 200 to manufacture the gas sensor 1000.

Here, the inner terminal 710 includes a cylindrical insertion portion 730 inserted into the cylindrical hole 340 of the gas sensor element 300, and an inner lead connection portion 740 extending from the insertion portion 730 to the rear end and connected to the lead wire 41. have. Similarly, the outer terminal 910 includes a cylindrical portion 930 that surrounds the rear end portion of the gas sensor element 300, and an outer lead connection portion 940 that extends from the cylindrical portion 930 to the rear end and is connected to a lead wire. Yes. Each of the inner lead connecting portion 740 and the outer lead connecting portion 940 has a plate shape, and has crimping portions 750 and 950 connected to the lead wire 41 on the rear end side.
Then, as shown in FIG. 14, when the inner terminal 710 and the outer terminal 910 are assembled to the separator 1110, the inner lead connecting portion 740 and the inner lead connecting portion 740 are inserted into the insertion holes 1115 and 1116 of the separator 1110 from the tip facing surface 1110a side. The outer lead connecting portion 940 is inserted. At this time, the rear end surfaces 730 a and 930 a of the insertion portion 730 and the cylindrical portion 930 are in contact with the front end facing surface 1110 a, and the inner terminal 710 and the outer terminal 910 are positioned and fixed to the separator 1110. When the heater 15 is gripped inside the insertion portion 730 of the inner terminal 710, the heater 15 is inserted through the center hole 1112 of the separator 1110, and the heater lead terminal of the heater 15 is inserted through the heater lead holes 1113 and 1114. It is connected to the line 41.

JP 2007-278806 A

  However, play is provided in the insertion holes 1115 and 1116 of the separator 1110 so that the inner lead connection portion 740 and the outer lead connection portion 940 can be smoothly inserted (that is, the inner lead connection portion 740 and the outer lead connection portion 940). The inner terminal 710 and the outer terminal 910 (the inner lead connection portion 740 and the outer lead connection portion 940) are inserted through the insertion holes even after the assembly. 1115 and 1116 (see arrows in FIG. 14). Accordingly, the insertion portion 730 and the cylindrical portion 930 also move, and a deviation occurs between the axis of the insertion portion 730 and the cylindrical portion 930 and the axis of the separator 1110 (the axis of the separator assembly A). As a result, even if the separator assembly A and the element assembly B are aligned and the separator assembly A is put on the sensor element assembly B, the axis of the gas sensor element 300 is not shifted from the axis of the insertion portion 730 or the cylindrical portion 930. As a result, the gas sensor element 300 may be lost or the inner terminal 710 or the outer terminal 910 may be deformed by the insertion part 730 or the cylindrical part 930 coming into contact with the gas sensor element 300. In addition to aligning the axes of the separator assembly A and the element assembly B, it is necessary to align the axis of the gas sensor element 300 with the axes of the insertion portion 730 and the cylindrical portion 930, which requires time for position adjustment and increases productivity. descend.

In particular, in the case of a sensor that does not have a heater (heaterless sensor), the above problem appears remarkably. In the gas sensor 1000 shown in FIG. 13 described above, the heater 15 is held by the inner terminal 710. Therefore, when the separator assembly A and the element assembly B are aligned and the separator assembly A is put on the sensor element assembly B, the heater 15 is first inserted into the gas sensor element 300 to serve as a guide. Therefore, when the insertion part 730 or the cylindrical part 930 is assembled to the gas sensor element 300, the deviation between the axis of the insertion part 730 of the inner terminal 710 or the cylindrical part 930 of the outer terminal 910 and the axis of the gas sensor element 300 can be reduced. Therefore, even if the inner terminal 710 and the outer terminal 910 move within the separator 1110, positioning is easy. On the other hand, in the case of a sensor that does not have a heater, since there is no guide effect by the heater, when the inner terminal 710 and the outer terminal 910 move in the separator 1110, the axis of the gas sensor element 3 and the axis of the insertion portion 730 or the cylindrical portion 930 It is difficult to reduce the deviation.
Therefore, the present invention can securely fix the outer terminal or the inner terminal to the separator while preventing the loss of the gas sensor or the deformation of the outer terminal or the inner terminal, and can securely connect these terminals to the gas sensor element. For the purpose of provision.

  In order to solve the above-described problems, a gas sensor according to the present invention includes a bottomed cylindrical element body that extends in the axial direction, has a cylindrical hole that is exposed to a gas to be measured and that opens toward the rear end, and A gas sensor element having an inner electrode provided on the inner surface of the element main body, a cylindrical insertion part inserted into the cylindrical hole of the gas sensor element and connected to the inner electrode, and a rear end side from the insertion part An inner terminal having an inner lead connection portion extending to the lead wire and a rear end surface of the insertion portion of the inner terminal abutting on the front end of the inner terminal, and connecting the inner lead to the insertion hole And a cylindrical separator that pushes the insertion portion into the cylindrical hole of the gas sensor element, wherein the separator is recessed from the front-facing surface toward the rear end side. Has one recess , The insert, when in contact with the forward-facing surface of the separator, first convex portion to be fitted into the first recess is protruded from the rear end face of the insertion portion.

According to this gas sensor, since the first convex portion is fitted into the first concave portion, the inner terminal is firmly held by the separator at at least two positions of the insertion hole and the first concave portion. Therefore, it can suppress that an inner side terminal moves with respect to a separator, after attaching an inner side terminal to a separator. Thereby, it can suppress that the axis line of an insertion part and the axis line of a separator (axis line with a separator assembly) shift | deviate, Furthermore, it can suppress that the axis line of a gas sensor element and the axis line of an insertion part shift | deviate. As a result, it is avoided that the gas sensor element is lost, the inner terminal is deformed, or time is required for position adjustment, and the gas sensor element can be reliably connected.
In addition, play can be provided in the insertion hole of the separator, and the inner lead connecting portion can be smoothly inserted into the insertion hole of the separator.

  Furthermore, in the gas sensor of the present invention, a metal shell that surrounds the gas sensor element and holds the gas sensor element, a front end side is engaged with the metal shell, and extends toward a rear end side from the metal shell, A cylindrical outer cylinder surrounding the separator, and the distal end of the insertion portion projects beyond the distal end of the outer cylinder. Thereby, even in the separator assembly in which the separator to which the inner terminal is assembled is arranged, the inner terminal is not completely covered by the outer cylinder. Therefore, when the separator assembly is put on the rear end of the sensor element assembly including the gas sensor element, the insertion portion can be used as an alignment guide, and the axis of the gas sensor element and the axis of the insertion portion can be further suppressed from shifting. . In particular, in the case of a heaterless sensor having no heater, the present invention is effective because the tip of the insertion portion serves as a positioning guide instead of the heater.

Furthermore, in the gas sensor of the present invention, the insertion portion has a slit that extends in the axial direction from the leading edge to the trailing edge of the gas sensor, and has a C-shaped cross section that can elastically reduce itself. Two or more first convex portions of the insertion portion and two or more first concave portions of the separator are formed on a virtual circle centered on the axis, and a plurality of the first convex portions when not inserted into the first concave portion. the diameter of the virtual circle connecting the outer surface of the first convex portions and K _0, the diameter of the virtual circle connecting the outer wall of the plurality of the first recess when the K _1, may satisfy a relation of K _0> K _1.

According to the gas sensor, since K ₁ is smaller than K _0, when fitting the first protrusion into the first recess, so that the insertion portion is fitted with reduced diameter. For this reason, the first convex portion of the insertion portion tends to spread outward due to the elastic force and abuts against the outer wall of the first concave portion, so that the first convex portion is firmly held by the first concave portion.

Furthermore, in the gas sensor of the present invention, the insertion portion has a slit that extends in the axial direction from the leading edge to the trailing edge of the gas sensor, and has a C-shaped cross section that can elastically reduce itself. Two or more of the first convex portion of the insertion portion and the first concave portion of the separator are formed on a virtual circle centered on the axis, and a virtual circle connecting outer walls of the plurality of first concave portions. the diameter and K _1, the diameter of the virtual circle connecting the inner walls of the plurality of the first recess and K _2, when the inner diameter of the cylindrical hole and a K _3, satisfies the relation _{K 1>} K _3> K ₂ Good.

According to the gas sensor, when inserting the inner fixed to the separator terminal (insertion portion) into the cylinder bore of the gas sensor element, K ₃ is narrower than K _1, the insertion portion is further reduced in diameter. As a result, the insertion portion tends to spread outward by the elastic force in the cylindrical hole, and comes into contact with the inner wall of the cylindrical hole. Further, since K ₂ is narrower than K ₃ , even if the interval between the first convex portions is narrowed, the first convex portion does not contact the inner wall of the first concave portion, so that the insertion portion is not affected by the first concave portion. Can be reduced in diameter along the cylindrical hole of the gas sensor element. As a result, the insertion portion is firmly held by the gas sensor element, and electrical connection is ensured. At this time, the first convex portion is disposed in the space of the first concave portion, but there is no problem because the insertion portion is already held in the cylindrical hole.

  Further, the gas sensor of the present invention includes 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 element body; An outer terminal having a cylindrical portion surrounding the gas sensor element and connected to the outer electrode; and an outer lead connecting portion extending from the cylindrical portion to a rear end side and connected to a lead wire; and A cylinder in which the surface facing the front end abuts on the rear end surface of the cylindrical portion, and the outer lead connecting portion is inserted into the insertion hole of the cylindrical portion so as to surround the cylindrical portion around the rear end portion of the gas sensor element. The separator has a second recess that is recessed from the tip-facing surface toward the rear end side, and the tubular portion contacts the tip-facing surface of the separator. When the second recess Second convex portion to be input is protruded from the rear end face of the tubular portion.

According to this gas sensor, since the second convex portion is fitted into the second concave portion, the outer terminal is firmly held by the separator at at least two locations of the insertion hole and the second concave portion. Therefore, it can suppress that an outer side terminal moves with respect to a separator, after attaching an outer side terminal to a separator. Thereby, it can suppress that the axis line of a cylindrical part and the axis line of a separator (axis line with a separator assembly) shift, Furthermore, it can suppress that the axis line of a gas sensor element and the axis line of a cylindrical part shift | deviate. As a result, it is possible to avoid the loss of the gas sensor element, the deformation of the outer terminal, or the time required for the position adjustment, and a reliable connection with the gas sensor element can be achieved.
In addition, play can be provided in the insertion hole of the separator, and the outer lead connecting portion can be smoothly inserted into the insertion hole of the separator.

Furthermore, in the gas sensor of the present invention, the cylindrical portion has a C-shaped cross section having a slit extending in the axial direction from the leading end edge to the trailing end edge thereof and capable of elastically expanding itself. And the said 2nd convex part of the said cylindrical part and the said 2nd recessed part of the said separator are each formed in two or more on the virtual circle centering on the said axis line, and when there are some not when it fits in the said 2nd recessed part the diameter of the virtual circle connecting the inner surface of the second projecting portion and D _0, when the diameter of the virtual circle connecting the inner wall of a plurality of said second recess has a D _1, when satisfying the relationship D 0 _{<D 1} Good.

According to this gas sensor, since D ₁ is wider than D ₀ , when the second convex portion is fitted into the second concave portion, the cylindrical portion is fitted while being expanded in diameter. For this reason, the second convex portion of the cylindrical portion tends to shrink inward due to the elastic force and comes into contact with the inner wall of the second concave portion, so that the second convex portion is firmly held by the second concave portion.

Furthermore, in the gas sensor of the present invention, the cylindrical portion has a C-shaped cross section having a slit extending in the axial direction from the leading edge to the trailing edge of the cylindrical portion, and capable of elastically reducing the diameter thereof. And two or more of the second convex part of the cylindrical part and the second concave part of the separator are each formed on a virtual circle centered on the axis,
The diameter of the virtual circle connecting the plurality of inner wall of the second recess and D _1, the diameter of the virtual circle connecting the outer wall of a plurality of said second recess and D _2, when the outer diameter of the gas sensor element was set to D ₃ , D ₁ <D ₃ <D ₂ may be satisfied.

According to the gas sensor, when fitted the outer terminal fixed to the separator (cylindrical portion) of the rear end portion of the gas sensor element, D ₃ since wider than D _1, the tubular portion further enlarged. Thereby, the cylindrical portion tries to shrink inward by an elastic force around the gas sensor element, and comes into contact with the side surface of the rear end portion of the gas sensor element. Further, since D ₂ is wider than D ₃ , even if the distance between the second convex portions is widened, the second convex portions do not come into contact with the outer wall of the second concave portion. The diameter of the portion can be increased along the outer wall of the gas sensor element. As a result, the cylindrical portion firmly holds the gas sensor element, and electrical connection is ensured. At this time, the second convex portion is disposed in the space of the second concave portion. However, since the cylindrical portion already holds the gas sensor element, there is no problem.

  According to the present invention, the outer terminal or the inner terminal can be firmly fixed to the separator while preventing the gas sensor from being lost or the inner terminal or the outer terminal is deformed, and these terminals can be securely connected to the gas sensor element. it can.

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 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 a gas sensor element and an outer side terminal. It is a perspective view which shows the structure of an inner side terminal. It is the top view which looked at the separator from the front end side. It is the top view which looked at the separator which has arrange | positioned the inner side terminal and the outer side terminal from the front end surface. It is sectional drawing cut | disconnected by the AA line of FIG. It is sectional drawing cut | disconnected by the BB line of FIG. When set to K _0> K _1, it is a cross-sectional view showing an aspect of fitting the first protrusion into the first recess. K _1> of _{K 3>} When set to K _2, is a cross-sectional view showing the positional relationship between the first protrusion first recess. D 0 _<when set to D _1, it is a cross-sectional view showing an aspect of fitting the second protrusion in the second recess. _{D 1} << D 3 <when set to _{D 2,} is a cross-sectional view showing a second protrusion the positional relationship of the second recess. It is a figure which shows the aspect which assembles | assembles a separator assembly and a sensor element assembly, and manufactures the conventional gas sensor. It is the top view which looked at the separator in the conventional gas sensor from the front end side.

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. 3) that is tapered 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 while 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 inside the distal end portion 40 a of the outer cylinder 40. Furthermore, plate-like bases 74 and 94 of the inner terminal 71 and the outer terminal 91 are inserted into 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. The plate-like base 74 corresponds to the “inner lead connection portion” in the claims, and the plate-like base 94 corresponds to the “outer lead connection portion” in the claims.

  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 inner terminal 71 and 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 40 b 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).

  When the gas sensor 100 is manufactured, as shown in FIG. 2, first, the sensor element assembly B is assembled by 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. Then, when the axis lines of the separator assembly A and the sensor element assembly B are aligned 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 becomes the cylinder at the rear end of the gas sensor element 3. It is fitted in the 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 on 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.

Here, as shown in FIG. 3, 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, the lead 3cL extends from the outer electrode 3c toward the rear end, and further the gas sensor element. 3 is connected from the lead 3cL to the electrode pad 3cp at the rear end of the outer surface. Accordingly, the cylindrical portion 93 is accurately connected to the electrode pad 3cp. However, in the present invention, the lead 3cL and the electrode pad 3cp are regarded as the “outer electrode 3c” without particular distinction.
The inner electrode 3b (not shown) is provided on the inner surface from the front end to the rear end of the element body 3s. Similarly to the outer electrode 3c, the inner electrode 3b is regarded as an “inner electrode 3b” when a lead or an electrode pad is connected to the inner electrode 3b.

The following characterizing portions of the present invention will be described.
FIG. 4 is a perspective view of the inner terminal 71. The inner terminal 71 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 74 is formed on the rear end side of the inner terminal 71, and a connection end portion 75 that is caulked and connected to the core wire of the lead wire 141 is disposed on the rear end of the plate-like base portion 74. An insertion portion 73 is connected to the tip of the plate-like base portion 74. Further, a wide portion 74w wider than other portions is formed on the center side in the axial direction of the plate-like base portion 74, and the central portion of the wide portion 74w is punched into a U-shape with the rear end side fixed, and the wide portion 74w A cut-and-raised portion 74Y cut and raised is provided on the back side (surface opposite to the front side).
When the plate-like base portion 74 is inserted into the insertion hole 115 (see FIG. 5) of the separator 111, the width of the wide width portion 74w is substantially equal to the interval between the two horizontal hole portions 115a. Is positioned. The cut-and-raised portion 74Y is in contact with the outer end wall of the insertion hole 115, and the plate-like base 74 is held in the insertion hole 115 by its spring force.

The insertion portion 73 has a cylindrical shape centered on the axis O, and has a slit M along the generatrix on the side opposite to the plate-like base portion 74. Therefore, when cut along a plane perpendicular to the axis O, the insertion portion 73 is substantially C-shaped, and the insertion portion 73 can be elastically reduced in diameter by a spring force. On the rear end side of the insertion portion 73, four piece-like locking portions 73 b are formed by horizontally folding each rear end outward in the radial direction of the insertion portion 73. As will be described later, the rear end surface of the locking portion 73b is in contact with the front-facing surface of the separator 111.
Moreover, in the insertion part 73, the 1st convex part 73a protrudes in the back end side from the latching | locking part 73b in the position between the two latching | locking parts 73b. Then, in the free state in which force in the radial direction in the insertion portion 73 is not applied, the spacing of the outer surface of the first projection 73a is in the K _0. When a plurality of (for example, four) first convex portions 73a are provided, K ₀ is not the distance between adjacent first convex portions 73a, but is concentric with the center of the insertion portion 73 in a plane perpendicular to the axis O direction. (That is, a circle centered on the axis O) and represented by a diameter of a virtual circle connecting the outer surfaces of the first convex portions 73a.

On the other hand, on the distal end side of the insertion portion 73, two tapered portions 73c having a tapered diameter that extend in a tapered manner extend in a leg shape. Each taper portion 73 c is first inserted into the gas sensor element 3 and is guided by the taper portion 73 c so that the insertion portion 73 is press-fitted into the gas sensor element 3.
The outer diameter of the insertion portion 73 is larger than the inner diameter K ₃ (see FIG. 2) of the cylindrical hole 3d of the sensor element 3, and when the insertion portion 73 is press-fitted into the sensor element 3, the insertion portion 73 is expanded by a spring force. It is opened and pressed against the inner electrode of the gas sensor element 3.

  Next, the configuration of the outer terminal 91 will be described with reference to FIG. Similar to the inner terminal 71, the outer terminal 91 is elongated from the front end to the rear end, and is integrally formed by bending a thin metal plate. The configuration of the plate-like base portion 94 of the outer terminal 91 is substantially the same as that of the plate-like base portion 74, and the configurations of the connection end portion 95 and the wide width portion 94w are also the same, and the description thereof is omitted. Similarly to the inner terminal 71, when the plate-like base portion 94 is inserted into the insertion hole 116 (see FIG. 5) of the separator 111, the width of the wide width portion 94w is substantially equal to the distance between the both side hole portions 116a. 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 tip of the plate-like base portion 94 is connected to the cylindrical portion 93. The cylindrical portion 93 has a cylindrical shape similar to that of the insertion portion 73 and has a slit N along the generatrix on the side opposite to the plate-like base portion 94. Then, the inner diameter of the cylindrical portion 93 is smaller than the outer diameter D ₃ of the rear end portion of the gas sensor element 3 _(see FIG. 2), the spring force a cylindrical portion 93 when the flared externally fitted to the gas sensor element 3 As a result, the cylindrical portion 93 is contracted and pressed against the outer electrode 3 c of the gas sensor element 3.
Further, a total of eight piece-like guide portions 93b in which the tip portion is turned back radially outward of the cylindrical portion 93 are radially provided on the distal end side of the cylindrical portion 93 (only five are shown in FIG. 3). Is formed. The distal end of the guide portion 93 b is further lowered from the distal end of the tubular portion 93 toward the distal end, and serves as a guide when the tubular portion 93 is externally fitted to the gas sensor element 3.
Furthermore, on the rear end side of the cylindrical portion 93, two second convex portions 93a protrude toward the rear end side. In the free state in which no force is applied to the cylindrical portion 93 in the radial direction, the interval between the inner surfaces of the second convex portions 93a is D ₀ (see FIG. 11). When a plurality of (for example, four) second convex portions 93a are provided, D ₀ is not the distance between adjacent second convex portions 93a, but the center of the cylindrical portion 93 on the plane perpendicular to the axis O direction. A concentric circle (that is, a circle centered on the axis O) is represented by the diameter of a virtual circle that connects the inner surfaces of the second convex portions 93a.

Next, the configuration of the separator 111 will be described with reference to FIG. FIG. 5 is a plan view of the separator 111 viewed from the front end side. The separator 111 includes a pair of insertion holes 115 and 116 disposed radially outward from the center, a pair of first recesses 117 into which the first protrusions 73 a of the inner terminal 71 are fitted, and a second of the outer terminal 91. And a pair of second concave portions 119 into which the convex portions 93a are fitted.
The two first recesses 117 are respectively arranged to face radially outward from the center, and the two second recesses 119 are respectively arranged to be radially outward from the center and opposed to the outside of the first recess 117. Has been. The first recess 117 and the second recess 119 are arranged on a straight line L passing through the center of the separator 111, and the insertion holes 115 and 116 are another straight line T passing through the center of the separator 111 while being orthogonal to the straight line L. Is placed on top.
The insertion holes 115 and 116 are opened in a substantially rectangular shape parallel to the radial direction of the separator 111, and lateral hole portions 115a and 116a extend from the vicinity of the outer end in the radial direction to the left and right in the circumferential direction. Accordingly, the peripheral edges of the insertion holes 115 and 116 have a substantially cross shape.

Next, referring to FIGS. 6 to 8, the manner in which the inner terminal 71 and the outer terminal 91 are assembled to the separator 111 will be described. 6 is a plan view of the separator 111 in which the inner terminal 71 and the outer terminal 91 are arranged as viewed from the front end surface. FIG. 7 is a cross-sectional view taken along line AA in FIG. 6, and FIG. It is sectional drawing cut | disconnected by the BB line. 6 corresponds to the straight line L in FIG. 5, and the BB line in FIG. 6 corresponds to the straight line T in FIG. In FIG. 6, the insertion holes 115 and 116, the first recess 117, and the second recess 119 are omitted.
First, two lead wires 141 are passed through the insertion holes 115 and 116 from the rear end side of the separator 111 through the grommet 131 in advance. Then, the leading end of one lead wire 141 is caulked and connected to the connecting end portion 75 of the inner terminal 71 disposed on the leading end side of the separator 111. When the plate-like base portion 74 of the inner terminal 71 is inserted into the insertion hole 115 of the separator 111, the wide width portion 74W is disposed in the horizontal hole portion 115a of the insertion hole 115, and the cut-and-raised portion 74Y is the outer end wall of the insertion hole 115. (FIGS. 5 and 8). Further, the rear end surface of the locking portion 73b comes into contact with the front-facing surface 111S of the separator 111, the plate-like base portion 74 is positioned without being inserted any more, and the inner terminal 71 is locked (FIG. 8).
Furthermore, as shown in FIG. 7, when the rear end surface (locking portion 73 b) of the insertion portion 73 comes into contact with the leading end facing surface 111 s of the separator 111, the first convex portion 73 a is fitted into the first concave portion 117. As a result, the inner terminal 71 is firmly held by the separator 111 at least in two places, the insertion hole 115 and the first recess 117, so that after the inner terminal 71 is assembled to the separator 111, the inner terminal 71 is not attached to the separator 111. It is possible to suppress movement (turning in the radial direction).

Similarly, as shown in FIG. 6, the outer terminal 91 is disposed outside the inner terminal 71 on the leading end side of the separator 111. Then, the tip end of another lead wire 141 is caulked and connected to the connection end portion 95 of the outer terminal 91. When the plate-like base portion 94 is inserted into the insertion hole 116 of the separator 111, the wide width portion 94W is disposed in the lateral hole portion 116a of the insertion hole 116, and the cut-and-raised portion 94Y comes into contact with the outer end wall of the insertion hole 116 ( FIG. 5, FIG. 8). Further, the rear end surface of the cylindrical portion 93 comes into contact with the front-facing surface 111S of the separator 111, the plate-like base portion 74 is positioned without being inserted any more, and the outer terminal 91 is locked (FIG. 8).
Further, as shown in FIG. 7, when the rear end surface of the cylindrical portion 93 comes into contact with the front-facing surface 111 s of the separator 111, the second convex portion 93 a is inserted into the second concave portion 119. As a result, the outer terminal 91 is firmly held by the separator 111 at least in two places, the insertion hole 116 and the second recess 119, so that the outer terminal 91 is not attached to the separator 111 after the inner terminal 71 is assembled to the separator 111. It is possible to suppress movement (turning in the radial direction).

In addition, the size of the opening of the first concave portion 117 and the second concave portion 119 is larger than that of the first convex portion 73a and the second convex portion 93a so that the first convex portion 73a and the second convex portion 93a can be smoothly inserted. It is getting bigger and there is a play between them. For example, in the example of FIG. 5, the first concave portion 117 and the second concave portion 119 are larger than the plate thickness of the first convex portion 73a and the second convex portion 93a.
Therefore, when the diameter K _{1 of the} virtual circle connecting the outer wall of the first recess 117 and the diameter D _{1 of the} virtual circle connecting the inner wall of the second recess 119 are set as follows (see FIG. 5), the first protrusion 73a. And the play between the 2nd convex part 93a, the 1st recessed part 117, and the 2nd recessed part 119 is eliminated, and it becomes possible to hold still more firmly.

FIG. 9 shows a mode in which the first convex portion 73a is inserted into the first concave portion 117 when K ₀ > K ₁ is set. K ₀ is a virtual circle that connects the outer surfaces of the first protrusions 73 a when the first protrusion 73 a is not inserted into the first recess 117, that is, in a free state in which no force is applied in the radial direction of the insertion part 73. Is the diameter. On the other hand, since the diameter K _{1 of the} imaginary circle connecting the outer walls of the first recess 117 is narrower than K ₀ , the insertion portion 73 is fitted with a reduced diameter when the first projection 73 a is fitted into the first recess 117. Will be. Therefore, the first convex portion 73a of the insertion portion 73 tries to spread outward due to the elastic force and comes into contact with the outer wall of the first concave portion 117, so that the first convex portion 73a is firmly held by the first concave portion 117.

In this way, the inner terminal 71 is firmly fixed to the separator 111. After the inner terminal 71 (the insertion portion 73) is inserted into the gas sensor element 3 (the cylindrical hole 3d), the inner terminal 71 is fixed. Is firmly held in the cylindrical hole 3d, and play may occur in the inner terminal 71 in the separator 111.
That is, as shown in FIG. 10, it is preferable to further set K ₁ > K ₃ > K ₂ . K ₂ is the diameter of a virtual circle that connects the inner walls of the first recess 117. When inserting the inner pin 71 fixed to the separator 111 (the insertion portion 73 of) into the cylinder bore 3d, _{K 3} is narrower than _{K 1,} the insertion portion 73 further reduced in diameter. As a result, the insertion portion 73 tries to spread outward by the elastic force in the cylindrical hole 3d, and comes into contact with the inner wall of the cylindrical hole 3d. Further, since K ₂ is narrower than K ₃ , even if the interval between the first protrusions 73 a is narrowed, the first protrusion 73 a does not come into contact with the inner wall of the first recess 117. The insertion portion 73 can be reduced in diameter along the cylindrical hole 3d of the gas sensor element 3. As a result, the insertion portion 73 is firmly held by the gas sensor element 3, and electrical connection is ensured. At this time, the first convex portion 73a is disposed in the space of the first concave portion 117. However, since the insertion portion 73 is already held in the cylindrical hole 3d, there is no problem.

FIG. 11 shows a mode in which the second convex portion 93a is inserted into the second concave portion 119 when D ₀ <D ₁ is set. D ₀ is a virtual connection between the inner surfaces of the second convex portions 93 a when the second convex portion 93 a is not fitted into the second concave portion 119, that is, in a free state in which no force is applied in the radial direction of the cylindrical portion 93. The diameter of the circle. In contrast, since the diameter D ₁ of the virtual circle connecting the inner wall of the second recess 119 is wider than D _0, when fitting the second convex portion 93a to the second recess 119, while the cylindrical portion 93 is expanded in diameter Will be inserted. For this reason, the second convex portion 93a of the cylindrical portion 93 tries to shrink inward due to the elastic force and comes into contact with the inner wall of the second concave portion 119, so that the second convex portion 93a is firmly held by the second concave portion 119.

In this manner, the outer terminal 91 is firmly fixed to the separator 111. After the outer terminal 91 (the cylindrical portion 93) is fitted on the rear end of the gas sensor element 3, the outer terminal 91 is Since the gas sensor element 3 is firmly held, play may occur in the outer terminal 91 in the separator 111.
That is, as shown in FIG. 12, it is better to set D ₁ <D ₃ <D ₂ . D ₂ is the diameter of a virtual circle connecting the outer walls of the second recess 119. When fitted to the rear end portion of the gas sensor element 3 an outer terminal 91 fixed to the separator 111 (the cylindrical portion 93 of), D ₃ since wider than D _1, the outer terminal 91 further enlarged. Thereby, the cylindrical portion 93 tries to shrink inward by the elastic force around the gas sensor element 3, and comes into contact with the side surface of the rear end portion of the gas sensor element 3. Furthermore, since _{D 2} is larger than _{D 3,} since the second convex portion 93a on the outer wall of the second recess 119 even spread the distance between the second convex portion 93a is prevented from contact, the influence of the second recess 119 The cylindrical portion 93 can be reduced in diameter along the gas sensor element 3. As a result, the cylindrical portion 93 is firmly held by the gas sensor element 3, and electrical connection is ensured. At this time, the second convex portion 93a is disposed in the space of the second concave portion 119. However, since the cylindrical portion 93 is already held by the gas sensor element 3, there is no problem.

The gas sensor 100 described above is a heaterless sensor that does not have a heater. In this case, if the distal end of the insertion portion 73 protrudes from the distal end of the outer cylinder 40 as shown in FIG. This is preferable because the insertion portion 73 serves as a positioning guide when the sensor element assembly B is put on the rear end. That is, by aligning the axis of the insertion portion 73 protruding from the outer cylinder 40 with the axis of the gas sensor element 3, the inner terminal 71 and the outer terminal 91 are in contact with the gas sensor element 3 at an incorrect position. It is less likely that each terminal is deformed and time is required for position adjustment.
Further, if the distal end of the insertion portion 73 is a guide portion (tapered portion 73c in FIG. 3) that is thinner than the inner diameter of the cylindrical hole 3d of the gas sensor element 3, the guide portion does not contact the inner electrode of the gas sensor element 3. Since the 73 main body is introduced into the gas sensor element 3, it is possible to suppress wear and loss of the inner electrode due to contact with the insertion portion 73.
Further, if the distal end of the insertion portion 73 protrudes greatly, the inner electrode of the gas sensor element 3 can be disposed on the distal end side, and the amount of material (noble metal, etc.) used for the inner electrode is reduced, and the cost is reduced. Down is planned.

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 the first concave portions and the corresponding first convex portions, and the number of the second concave portions and the corresponding second convex portions are not limited as long as one or more are formed, and the shape is not limited. Further, the present invention is not limited to a heaterless sensor, but can be applied to a gas sensor having a heater.
Furthermore, as a gas sensor element, as long as it is a cylindrical element, it can be used for an ammonia sensor element, an HC sensor element, an H ₂ sensor element, etc., in addition to the oxygen sensor element (λ sensor element) described above.

3 Gas sensor element 3b Inner electrode 3c Outer electrode 3d Tube hole of gas sensor element 3s Element body 40 Outer cylinder 71 Inner terminal 73 Insertion part 73a First convex part 75, 95 Lead connection part 91 Outer terminal 93 Cylindrical part 93a Second convex part 100 Gas sensor 111 Separator 111s Separator tip facing surface 115, 116 Insertion hole 117 First recess 119 Second recess 141 Lead wire 200 Metal shell 400 Outer cylinder O Axial direction M, N Slit K ₀ Virtual when not inserted into first recess Diameter of the circle K ₁ Diameter of the virtual circle connecting the outer walls of the plurality of first recesses K ₂ Diameter of the virtual circle connecting the inner walls of the plurality of first recesses K ₃ Inner diameter of the cylindrical hole D ₀ Virtual when not inserted into the second recess Diameter of the circle D ₁ Diameter of a virtual circle connecting the inner walls of the plurality of second recesses D ₂ Diameter of a virtual circle connecting the outer walls of the plurality of second recesses

Claims (7)

A bottomed cylindrical element body having a cylindrical hole extending in the axial direction and having a front end exposed to the gas to be measured and opened toward the rear end, and an inner electrode provided on the inner surface of the element main body A gas sensor element having
An inner side having a cylindrical insertion part inserted into the cylindrical hole of the gas sensor element and connected to the inner electrode, and an inner lead connection part extending from the insertion part to the rear end side and connected to a lead wire A terminal,
A cylinder whose own tip-facing surface abuts on a rear end surface of the insertion portion of the inner terminal, and the inner lead connection portion is inserted into the insertion hole, and the insertion portion is pushed into the cylinder hole of the gas sensor element. A gas sensor comprising:
The separator has a first recess that is recessed from the front-facing surface toward the rear end side,
A gas sensor in which a first convex portion that is inserted into the first concave portion protrudes from a rear end surface of the insertion portion when the insertion portion abuts against a front-facing surface of the separator. A metal shell that surrounds the gas sensor element and holds the gas sensor element, and a front end side is engaged with the metal shell, extends toward the rear end side of the metal shell, and surrounds the separator. A cylinder,
The gas sensor according to claim 1, wherein a distal end of the insertion portion projects beyond a distal end of the outer cylinder. The insertion part has a C-shaped cross section having a slit extending in the axial direction from the leading edge to the rear edge of the insertion part and capable of elastically reducing the diameter of the insertion part, and the first protrusion of the insertion part Two or more of the first recesses of the part and the separator are formed on virtual circles centered on the axis,
When the diameter of a virtual circle that connects the outer surfaces of the plurality of first protrusions when not fitted into the first recess is K _0, and the diameter of the virtual circle that connects the outer walls of the plurality of first recesses is K ₁ The gas sensor according to claim 1 or 2, satisfying a relationship of K ₀ > K ₁ . The insertion part has a C-shaped cross section that has a slit extending in the axial direction from the leading edge to the trailing edge of the insertion part and can elastically reduce the diameter thereof.
And two or more of the first convex portion of the insertion portion and the first concave portion of the separator are each formed on a virtual circle centered on the axis,
The diameter of the virtual circle connecting the outer wall of the plurality of the first recess and K _1, the diameter of the virtual circle connecting the inner walls of the plurality of the first recess and K _2, when the inner diameter of the cylindrical hole and a K _3, K _{1> K} 3> gas sensor according to any one of claims 1 to 3 satisfying the relation of _{K 2.} 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 element body;
An outer terminal having a cylindrical portion surrounding the gas sensor element and connected to the outer electrode; and an outer lead connecting portion extending from the cylindrical portion to the rear end side and connected to a lead wire;
The front-facing surface of the outer terminal contacts the rear end surface of the cylindrical portion, and the outer lead connecting portion is inserted into the insertion hole, and the cylindrical portion is disposed around the rear end of the gas sensor element. In a gas sensor comprising a cylindrical separator that surrounds
The separator has a second recess recessed from the front-facing surface toward the rear end side,
A gas sensor in which the second convex portion inserted into the second concave portion protrudes from the rear end surface of the cylindrical portion when the cylindrical portion abuts against the front-facing surface of the separator. The cylindrical portion has a C-shaped cross section that has a slit extending in the axial direction from the leading edge to the trailing edge of the cylindrical portion and can elastically expand itself.
And two or more of the second convex part of the cylindrical part and the second concave part of the separator are each formed on a virtual circle centered on the axis,
When the diameter of a virtual circle connecting the inner surfaces of the plurality of second convex portions when not inserted into the second concave portion is D ₀ and the diameter of a virtual circle connecting the inner walls of the plurality of second concave portions is D ₁ The gas sensor according to claim 5 , satisfying a relationship of D ₀ <D ₁ .


The cylindrical portion has a C-shaped cross section having a slit extending in the axial direction from the leading edge to the trailing edge of the cylindrical portion and capable of elastically reducing the diameter thereof.
And two or more of the second convex part of the cylindrical part and the second concave part of the separator are each formed on a virtual circle centered on the axis,
The diameter of the virtual circle connecting the plurality of inner wall of the second recess and D _1, the diameter of the virtual circle connecting the outer wall of a plurality of said second recess and D _2, when the outer diameter of the gas sensor element was set to D ₃ The gas sensor according to claim 5 or 6, which satisfies a relationship of D ₁ <D ₃ <D ₂ .

Images