JP2012233786A - Gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas sensor in which electric connection between an outside terminal and a gas sensor element is hardly cut.SOLUTION: A gas sensor 100 comprises: a gas sensor element 3 including a bottomed cylindrical element body 3s whose tip is exposed to gas to be measured and outside electrodes 3c provided on an outside surface from the tip of the element body to a rear end thereof; an outside terminal 91 including a cylindrical part 93 that encloses, at a tip thereof, the rear end of the gas sensor element from a radial direction and is electrically connected to the outside electrodes forms a cross section C shape formed with a slit M extending from a tip edge to a rear end edge in an axis line O direction and extends a diameter by elastic force when externally fitted to the rear end of the gas sensor element; and a separator 111 whose tip-facing surface 111S is in contact with a rear end surface of the cylindrical part and for externally fitting a tip of the cylindrical part into the rear end of the gas sensor. The rear end of the cylindrical part is provided with a first notch 93a connected to the rear end edge 93e and notched in the axis line direction toward the tip side.

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 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.
This gas sensor 1000 is manufactured as shown in FIG. First, the sensor element assembly B is assembled while holding the gas sensor element 3 inside the metal shell 20. Specifically, the gas sensor element 300 is disposed on a ceramic holder 170 disposed in the metal shell 200. Thereafter, a talc 600 is filled in a gap between the metal shell 200 and the gas sensor element 300, a ceramic sleeve 310 and a 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 with the inner terminal 710 on the inner side and the outer terminal 910 on the outer side is 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 separator 1110, and then the separator 1110 is brought into contact with the stepped 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 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. Similarly, the inner terminal 710 includes a cylindrical insertion portion 730 inserted into the rear end opening 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. Have. Each of the inner lead connection portion 740 and the outer lead connection portion 940 has a plate shape, and has crimping portions 750 and 950 connected to the lead wire 41 on the rear end side.
Further, the inner terminal 710 and the outer terminal 910 are held by inserting the inner lead connecting portion 740 and the outer lead connecting portion 940, respectively, into the insertion holes (not shown) of the separator 1110 from the leading end facing surface 1110a side of the separator 1110. . 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 separator assembly A is pushed into the sensor element assembly B, a pressurizing device (not shown) is used, and as shown in FIG. 17, the cylindrical portion 930 of the outer terminal 910 is attached to the tip-facing surface 1110a of the separator 1110. Push in with a predetermined stroke. (FIG. 17 (a)), thereby, the tip portion R ₂ of the tubular portion 930, by utilizing the fact that the diameter increases in its own elasticity, forming part of the rear portion near (outer electrode of the gas sensor element 300 ) (FIG. 17B).
By the way, if the ceramic separator 1110 and the gas sensor element 300 are in direct contact, the heat of the gas sensor element 300 may be taken away by the separator 1110 or the gas sensor element 300 may be damaged. It is done. For this reason, while the cylindrical part 930 is fitted to the gas sensor element 300 at its front end R ₂ , its rear end R ₁ is not fitted and the front end R ₂ is expanded in diameter, while the rear At the end R ₁ , the diameter of the tip R ₂ is reduced due to the reaction of expanding the diameter (FIG. 17B). In addition, since the separator 1110 pushes in the cylindrical portion 930, the pressing force between the leading end-facing surface 1110a of the separator 1110 and the rear end surface 930a of the cylindrical portion 930 increases, and the rear end R ₁ becomes self The expansion of the diameter is limited by the elastic force. As a result, there is a problem that the tubular portion 930 is deformed into a “C” shape, and the electrical connection and holding force between the tubular portion 930 and the outer electrode are not sufficient.

Therefore, by pressing the cylindrical portion 930 into the gas sensor element 300 by the separator 1110 in two steps, the pressing force that the separator 1110 and the cylindrical portion 930 press against each other is released, and the cylindrical portion 930 A technique has been developed in which the rear end R ₁ is expanded by its own elastic force so that the cylindrical portion 930 can be in close contact with the outer electrode (Patent Document 1).

JP 2007-278806 A

However, in the case of the technique described in Patent Document 1, since it is necessary to perform the pressing in two steps, the productivity may be reduced.
Further, the vibration of the vehicle or the like to which the gas sensor 1000 is attached is transmitted from the outer cylinder 400 through the separator 1110 and the outer terminal 910 to the contact point between the cylindrical portion 930 and the outer electrode of the gas sensor element 300. In the case of 910, the electrical connection of the contact may be lost momentarily due to vibration.
Therefore, an object of the present invention is to provide a gas sensor in which the electrical connection between the outer terminal and the gas sensor element is difficult to be disconnected.

In order to solve the above problems, a gas sensor according to the present invention includes a bottomed cylindrical element body that extends in the axial direction and whose tip is exposed to the gas to be measured, and the outer surface of the element body from the tip to the rear end. A gas sensor element having an outer electrode provided; and a cylindrical part that surrounds a rear end portion of the gas sensor element in a radial direction at its front end portion and is electrically connected to the outer electrode; And a cylindrical portion that expands by elastic force when it is fitted on the rear end of the gas sensor element. An outer terminal,
A gas sensor provided with a separator whose own tip-facing surface is in contact with a rear end surface of the cylindrical portion, and the front end portion of the cylindrical portion is fitted on a rear end portion of the gas sensor element,
The rear end portion of the tubular portion is provided with a first notch portion that is connected to the rear end edge and is notched in the axial direction toward the front end side.

According to this gas sensor, the front end portion of the cylindrical portion is fitted with the gas sensor element, while the rear end portion of the cylindrical portion is not fitted. At this time, the rear end portion is reduced in diameter due to the reaction that the front end portion expands, but a first cutout portion that is notched in the axial direction toward the front end side while being connected to the rear end edge is provided at the rear end portion. Therefore, the reaction force due to the reaction of expanding the diameter of the front end portion is reduced in the entire rear end portion. For this reason, the diameter reduction amount of the rear end portion is also reduced. Further, since the first cutout portion exists, the contact area between the rear end surface of the cylindrical portion and the front surface of the separator is also reduced. For this reason, even if the rear end portion is reduced in diameter due to the reaction of expanding the tip end portion of the cylindrical portion, the pressing force pressing the separator facing the tip end surface and the rear end surface of the cylindrical portion is reduced. The diameter of the rear end can be expanded to the original position by its own elastic force.
Therefore, the tip portion can easily return to a substantially parallel cylindrical shape, and the tip portion can be brought into close contact with the gas sensor element. As a result, the electrical connection between the outer terminal and the gas sensor element is not easily cut off.

  Furthermore, in the gas sensor of the present invention, when a plurality of the first cutout portions are provided intermittently in the circumferential direction of the rear end portion of the cylindrical portion, the amount of diameter reduction of the rear end portion is further reduced, The contact area of the rear end surface of the cylindrical portion with respect to the front surface of the separator is further reduced. Therefore, it is preferable because the rear end portion can be easily expanded to the original position by the elastic force, and the front end portion can be easily returned to a parallel cylindrical shape.

Furthermore, in the gas sensor of the present invention, when the cylindrical portion is viewed along the axial direction, the first notch portion is the slit when the slit is divided into three regions at intervals of 120 degrees starting from the slit. It is good to be disposed at least in a region including a midpoint opposite to.
Since the slit is connected from the rear end edge to the front end edge of the cylindrical portion, the same effect as the first notch portion is exhibited. Therefore, by providing the first notch in the vicinity of the midpoint at least on the opposite side of the slit, the amount of diameter reduction at the rear end is reduced in a balanced manner in the circumferential direction, and the rear end is elastic. When the diameter is expanded to the original position, the diameter can be expanded in a balanced manner in the radial direction, and the cylindrical portion is easily returned by a substantially parallel cylindrical shape.

Furthermore, in the gas sensor of the present invention, when the cylindrical portion is viewed along the axial direction, the first notch portion sandwiches the midpoint of the cylindrical portion facing the slit, The first cutout may be disposed at least at a position closer to the midpoint than the slit.
Since the cylindrical portion expands and contracts in the radial direction starting from the midpoint as the starting point (fixed end), the reaction of expanding the tip at the rear end near the midpoint increases. Therefore, by arranging the first notch portion with the middle point in between and the first notch portion on one side with the middle point in between is arranged closer to the middle point than the slit, The reaction acting in the vicinity can be greatly reduced, and the above-described action can be further exhibited.

The first cutout portion may extend in the axial direction over the entire rear end portion of the tubular portion.
When the first cutout portion is provided at a part of the rear end portion of the gas sensor element, a region where the first cutout portion does not exist exists in the rear end portion, and in this region, the reaction of expanding the tip portion is caused. It cannot be reduced at the rear end. On the other hand, according to this configuration, since the first cutout portion is always present in the rear end portion, it is possible to reliably reduce the reaction against the diameter expansion of the front end portion.

  Further, the gas sensor of the present invention includes a bottomed cylindrical element body that extends in the axial direction and whose tip is exposed to the gas to be measured, and an outer electrode provided on the outer surface of the element body from the tip to the rear end. A cylindrical portion that is electrically connected to the outer electrode while holding the rear end portion of the gas sensor element in the radial direction at its front end portion, and from the front end edge to the rear end edge An outer terminal provided with a cylindrical portion that has a C-shaped cross section in which a slit extending in the axial direction is formed, and has a cylindrical portion that expands by elastic force when it is fitted on the rear end portion of the gas sensor element; A gas sensor comprising: a separator whose own tip-facing surface is in contact with a rear end surface of the cylindrical portion, and the front end portion of the cylindrical portion is fitted on a rear end portion of the gas sensor element; Between the tip part and the rear end part of the part, A second notch communicating with the slit in the circumferential direction is provided, and a total length in the circumferential direction of the second notch is such that the middle point of the cylindrical part facing the slit, the slit, It is more than the length of the circumferential direction.

  According to this gas sensor, the front end portion of the cylindrical portion is fitted with the gas sensor element, while the rear end portion of the cylindrical portion is not fitted. At this time, since the second notch portion is provided, the tip end portion expands in diameter, but the tip end portion and the rear end portion are separated by the second notch portion, and the rear end caused by the reaction of the tip end portion expanding in diameter. The diameter of the part is less likely to occur. That is, the front end can be expanded without being affected by the rear end, and when the front end is fitted to the gas sensor element, the front end is kept in a substantially parallel cylindrical shape. It will be in close contact.

  If the total circumferential length of the second notch is equal to or greater than the circumferential distance between the midpoint of the cylindrical portion facing the slit and the slit, the above effect can be obtained. If the total circumferential length of the two notches is less than the circumferential distance between the midpoint of the cylindrical portion and the slit, the portion where the second notch is not formed becomes longer, and the diameter of the tip increases. The diameter of the rear end portion due to the reaction is reduced, and the above effect cannot be obtained.

  Furthermore, in the gas sensor of the present invention, when the cylindrical portion is viewed along the axial direction, the second cutout portion is provided with the two midpoints of the cylindrical portion interposed therebetween. The ratio of separation between the front end portion and the rear end portion is increased, and the reduced diameter of the rear end portion due to the reaction of expanding the front end portion is further less likely to occur.

Furthermore, in the gas sensor of the present invention, when the cylindrical part is viewed along the axial direction, the circumferential length of each of the second notch parts is the circumferential direction between the slit and the middle point. It is good to be 1/2 or more of the length.
According to this configuration, the length of each second notch is increased, and the proportion of separation of the front end and the rear end increases accordingly, so that the rear end of the rear end due to the reaction of expanding the diameter of the front end is increased. Reduced diameter is more difficult to occur.

  According to this invention, the cylindrical portion of the outer terminal can be stably held on the gas sensor element, and the electrical connection between the outer terminal and the gas sensor element is difficult to be disconnected.

It is sectional drawing which cut | disconnected the gas sensor which concerns on the 1st Embodiment of this invention in the surface which follows an axial direction. It is a perspective view which shows the structure of the gas sensor element and outer side terminal in 1st Embodiment. It is a perspective view which shows the state which fitted the cylindrical part of the outer side terminal to the outer peripheral surface of the rear end side of a gas sensor element. It is the side view which looked at FIG. 3 from the direction perpendicular | vertical to an axial direction. It is the top view which looked at the separator from the front end side. It is a figure which shows the effect by providing a 1st notch part when pushing an outer side terminal into a gas sensor element with a separator. It is the top view which looked at FIG. 3 in the axial direction. The side view at the time of changing various fitting depth of the cylindrical part to a gas sensor element is shown. It is a figure which shows the aspect which assembles | assembles a separator assembly and a sensor element assembly, and manufactures a gas sensor. It is a perspective view which shows the structure of the gas sensor element and outer side terminal in 2nd Embodiment. It is a perspective view which shows the state which fitted the cylindrical part of the outer side terminal to the outer peripheral surface of the rear end side of a gas sensor element. It is a figure which shows the effect by providing a 2nd notch part when pushing an outer side terminal into a gas sensor element with a separator. It is the top view which looked at FIG. 10 in the axial direction. It is a perspective view which shows the modification of the outer side terminal in 2nd Embodiment. It is a perspective view which shows another modification of the outer side terminal in 2nd Embodiment. It is a figure which shows the aspect which manufactures the conventional gas sensor. It is a figure which shows the conventional method at the time of pushing an outer side terminal into a gas sensor element with a separator.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a cross-sectional structure in which a gas sensor 100 according to a first 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 cylindrical solid electrolyte body (corresponding to “element main body” in the claims, see FIG. 2) that is tapered toward the tip, and an inner periphery of the solid electrolyte body. The inner electrode 3b and the outer electrode 3c are formed on the surface and the outer peripheral surface, respectively. 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.

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.

  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. As the grommet 131, for example, a rubber cap made of silicon rubber, fluorine rubber, or the like can be used.

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

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

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

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

Next, the configuration of the outer terminal 91, which is a characteristic part of the present invention, will be described with reference to FIGS. The outer terminal 91 extends from the front end to the rear end and is integrally formed by bending a thin metal plate (corrosion-resistant heat-resistant superalloy plate) punched into a predetermined shape. A plate-like base portion 94 is formed on the rear end side of the outer terminal 91, and a connection end portion 95 that is caulked and connected to the core wire of the lead wire 141 is disposed on the rear end side of the plate-like base portion 94. A cylindrical portion 93 is connected to the distal end side of the plate-like base portion 94. Further, a wide portion 94w that is wider than other portions is formed on the center side in the axial direction of the plate-like base portion 94, and the central portion of the wide portion 94w is punched into a U-shape with the rear end side fixed, and the wide portion 94w A cut-and-raised portion 94Y cut and raised on the back side (the surface opposite to the front side) is provided.
When the plate-like base portion 94 is inserted into the insertion hole 116 (see FIG. 5) of the separator 111, the plate-like base portion 94 is positioned in the insertion hole 116. Further, the cut and raised portion 94Y contacts the outer end wall of the insertion hole 116, and the plate-like base portion 94 is held in the insertion hole 116 by the spring force.

On the other hand, the cylindrical portion 93 has a cylindrical shape centered on the axis O, and has a C-shaped cross section having a slit M along the generatrix on the side opposite to the plate-like base portion 94. The inner diameter of the cylindrical portion 93 is smaller than the outer diameter of the rear end portion of the gas sensor element 3, and when the cylindrical portion 93 is fitted on the gas sensor element 3 and expanded, the cylindrical portion 93 is contracted by the spring force. The gas sensor element 3 is pressed against the outer electrode 3c.
Further, the rear end R ₁ of the cylindrical portion 93, the first cut-out portion 93a formed by cutting in a rectangular shape toward the distal end side while connected to the rear end edge 93e is provided four.
Although described in FIG. 7, the position of the cylindrical portion 93 that faces the slit M when viewed in the direction of the axis O is a middle point C. The cylindrical portion 93 is radially expanded and contracted from the middle point C as a starting point (fixed end), and a plate-like base 94 is connected to the cylindrical portion 93 at the position of the middle point C.

On the other hand, as shown in FIG. 2, the outer electrode (detection electrode) 3c is formed on the distal end side of the element body 3s outer surface of the gas sensor element 3, and the outer electrode 3c extends over the entire circumference on the distal end side of the element body 3s. The provided detection portion 3cs, the linear lead portion 3cL extending from the detection portion 3cs to the rear end, and the lead portion 3cL (detection portion 3cs) provided at the rear end side of the element body 3s so as to extend in part in the circumferential direction. ) And a connection portion 3 cp connected to. The connecting portion 3cp is formed wider than the lead portion 3cL in the circumferential direction, and the connecting portion 3c and the lead portion 3cL are T-shaped. The inner electrode 3b (see FIG. 1) is provided on the surface of the inner hole 3d from the front end portion to the rear end portion of the element body 3s.
Then, as shown in FIG. 3, the distal end portion of the cylindrical portion 93 of the outer terminal 91 is fitted on the outer peripheral surface on the rear end side of the gas sensor element 3, and the outer electrode 3 c (the connection portion 3 cp) and the cylindrical portion 93 are fitted. Is electrically connected to (the front end portion R ₂ ).

FIG. 4 is a side view of FIG. 3 viewed from a direction perpendicular to the axial direction O. FIG. Of the tubular portion 93, rearward of the front end edge 93af of the first notch portion 93a is a rear end _{R 1,} and the leading end side of the distal edge 93af has a tip _{R 2.} Accordingly, a gap (a part of the rear end R ₁ ) is provided in the axis O direction between the separator (not shown) in contact with the cylindrical portion 93 and the gas sensor element 3. It prevents direct contact and the heat of the gas sensor element 3 being transmitted to the separator 111 or the gas sensor element 3 being damaged.
In addition, the fitting depth of the tubular portion 93 to the gas sensor element 3 is set so that the leading edge 93af of the first cutout portion 93a is positioned at the leading edge from the trailing edge 3e of the gas sensor element 3.

FIG. 5 is a plan view of the separator 111 as viewed from the front-facing surface, and the separator 111 includes a pair of insertion holes 115 and 116 disposed radially outward from the center. 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. The insertion holes 115 and 116 are arranged on a straight line T passing through the center of the separator 111 while facing the outer side in the radial direction from the center of the separator 111.
Then, the 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 95 of the outer terminal 91 disposed on the leading end side of the separator 111. When the plate-like base portion 94 is inserted into the insertion hole 116 of the separator 111, the rear end surface 93b of the cylindrical portion 93 comes into contact with the tip-facing surface 111S of the separator 111, and the plate-like base portion 94 is positioned without being inserted further. Then, the outer terminal 91 is locked.
Similarly, the inner terminal 71 is disposed inside the outer terminal 91 on the leading end side of the separator 111. Then, the tip end of the other lead wire 141 is caulked and connected to the connection end 75 of the inner terminal 71. Then, when the plate-like base portion 74 of the inner terminal 71 is inserted into the insertion hole 115 of the separator 111, the rear end surface of the insertion portion 73 (see FIG. 1) of the inner terminal 71 comes into contact with the tip-facing surface 111S of the separator 111, The shaped base 74 is positioned without being inserted any more, and the inner terminal 71 is locked. The plate-like base 74 and the connection end 75 of the inner terminal 71 have the same configuration as the plate-like base 94 and the connection end 95 of the outer terminal 91 shown in FIG.

Next, with reference to FIG. 6, the effect by providing the 1st notch part 93a when pushing the outer side terminal 91 into the gas sensor element 3 with the separator 111 is demonstrated. First, after attaching the outer terminal 91 to the separator 111, using a pressurizing device (not shown), the cylindrical portion 93 is pushed in with a predetermined stroke on the tip-facing surface 111a of the separator 111 (FIG. 6A). the distal portion R ₂ of the tubular portion 93 is fitted to the rear end side of the gas sensor element 3 (forming part of the outer electrode) (Figure 6 (b)). At this time, the tubular portion 93, while fitted to the gas sensor element 3 at the tip R _2, a part of the rear end R ₁ becomes non-fitted.
At this time, also in the present embodiment, the front end portion R ₂ is expanded in diameter, while the rear end portion R ₁ is contracted by the reaction of expanding the front end portion R _2, but the first notch portion 93a is provided. because you are, reaction force due to reaction to the enlarged diameter of the distal end portion R ₂ is smaller in the entire rear end. Therefore, also reduced diameter reduction of the rear end R _1.
Further, since the first cutout portion 93a exists, the contact area between the rear end surface 93b of the tubular portion 93 and the front end facing surface 111a of the separator 111 is also reduced. Therefore, even if the rear end R ₁ is reduced in diameter by the recoil tip R ₂ is expanded, pressing force for pressing each other and the rear end face 93b of the forward-facing surface 111a and the cylindrical portion 93 of the separator 111 is small As a result, the rear end R ₁ having a reduced diameter can be expanded to its original position by its own elastic force.

As described above, when pushed cylindrical portion 93 by the separator 111 to the gas sensor element 3, the rear end portion expanded in diameter R ₁ is the original position, and a tubular portion 93 is overall parallel tubular gas sensor Since it closely adheres to the outer surface of the element 3, the cylindrical part 93 can be stably held on the gas sensor element 3, and the electrical connection between the cylindrical part 93 and the outer electrode 3c is ensured. In addition, since the pressing by the separator 111 may be performed once, the productivity is excellent.
Further, the vibration of the vehicle or the like to which the gas sensor 100 is attached is transmitted from the outer cylinder 40 through the separator 111 and the outer terminal 91 to the contact point between the cylindrical portion 93 and the outer electrode 3c of the gas sensor element 3, but the first notch portion. Since 93a exists, the contact area between the cylindrical portion 93 and the separator 111 is reduced, and vibrations transmitted from the separator 111 to the cylindrical portion 93 are reduced, so that the electrical connection of the contacts is difficult to be disconnected.

FIG. 7 is a top view of FIG. 3 as viewed along the direction of the axis O. FIG. When dividing the cylindrical portion 93 into three regions at intervals of 120 degrees slits M in origin, it is arranged two first cut-out portion 93a in a region S ₁ which includes a center point C which faces the slit M Yes.
Here, since the slit M penetrates from the rear end edge to the front end edge of the cylindrical portion 93, the same effect as the first notch portion is exhibited. Therefore, at least in the vicinity of the middle point C in the slit M to a position on the opposite side by providing the first cut-out portion 93a, a good balance is reduced diameter reduction of the rear end R ₁ in the circumferential direction, the rear end when part R ₁ is expanded to the original position by the elastic force, it can be well-balanced expanded radially, easily return the tubular portion 93 by substantially parallel tubular.
The position of the slit M is a position passing through the slit M, and the position of the midpoint C is a position where a straight line X passing through the position of the slit M and the center of the cylindrical portion 93 intersects the cylindrical portion 93.

Further, as shown in FIG. 7, when viewed in the axial direction O, the two first cutout portions 93a sandwich the midpoint C, and the first cutout portion 93a disposed on one side has a slit M. It is arranged at a position closer to the midpoint C than. As already described, since the cylindrical portion 93 expands and contracts in the radial direction with the middle point C as the starting point (fixed end), the distal end R ₂ is expanded at the rear end R _{1 in the} vicinity of the middle point C. The reaction to be increased becomes larger. Therefore, by arranging the first cutout portion 93a with the midpoint C sandwiched therebetween, and by arranging the first cutout portion 93a on one side with the midpoint sandwiched therebetween closer to the midpoint C than the slit M, The reaction acting in the vicinity of the point C can be greatly reduced, and the above-described action can be further exhibited.

In addition, as shown in FIG. 4, the fitting depth of the cylindrical part 93 to the gas sensor element 3 is such that the leading edge 93af of the first notch part 93a is positioned at the leading edge from the rear edge 3e of the gas sensor element 3. May be set.
FIG. 8 shows a side view when the fitting depth of the cylindrical portion 93 to the gas sensor element 3 is variously changed. When the front end edge 93af is positioned at the front end from the rear end edge 3e as in the present embodiment (FIG. 8A), and when the front end edge 93af is flush with the rear end edge 3e (FIG. 8B), Since the first cutout portion 93a exists in all the gaps between the gas sensor element 3 and the separator 111, the above-described action can be reliably exhibited. Since it is complicated to adjust the leading edge 93af and the trailing edge 3e to be flush with each other as shown in FIG. 8B, the cylindrical portion 93 is positioned at the position shown in FIG. It is preferable that the fitting depth is set.
On the other hand, if the leading edge 93af is located at the rear end of the rear end edge 3e (FIG. 8 (c)), the region _{R 3} where the first cut-out portion 93a does not exist is interposed in a gap between the gas sensor element 3 and the separator 111 , can not be reduced recoil tip R ₂ in the region R ₃ is enlarged at the rear end R _1, FIG. 8 (a), the also reducing action described above compared to (b). However, the case of FIG. 8C is also superior to the conventional cylindrical part that does not have the first cutout part in that it exhibits the above action, and is therefore included in the present invention.

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

  Next, a gas sensor according to a second embodiment of the present invention will be described with reference to FIGS. Since the gas sensor according to the second embodiment has the same configuration as the gas sensor according to the first embodiment except that the configuration of the outer terminal 97 is different, the description and illustration of the same components are appropriately omitted. .

10 and 11 show the configuration of the outer terminal 97 in the gas sensor according to the second embodiment. Similar to the outer terminal 91, the outer terminal 97 is elongated 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 cylindrical portion 99 is formed on the front end side of the outer terminal 97, and a plate-like base portion 94 and a connection end portion 95 having the same configuration as the outer terminal 91 are provided on the rear end side of the cylindrical portion 99.
On the other hand, the cylindrical portion 99 has a cylindrical shape centered on the axis O, and has a slit N along the generatrix on the side opposite to the plate-like base portion 94. The inner diameter of the cylindrical portion 93 is smaller than the outer diameter of the rear end portion of the gas sensor element 3, and when the cylindrical portion 93 is fitted on the gas sensor element 3 and expanded, the cylindrical portion 93 is contracted by the spring force. The gas sensor element 3 is pressed against the outer electrode 3c.

Furthermore, between the rear end edge 99e and the front end edge 99f of the cylindrical part 99, two second cutout parts 99a communicating in the radial direction from the slit N are provided. Each second notch 99a has the same position in the axial direction O, but extends to the opposite side in the radial direction across the slit N. Here, the total length L ₁ of the circumferential direction of the second cut-out portion 99a is a distance L2 above the circumferential direction of the slit N and the midpoint C (see FIG. 13). Note that the total length L ₁ refers to the sum of the circumferential length of each second cut-out portion 99a (see FIG. 13).

And as shown in FIG. 11, the front-end | tip part of the cylindrical part 99 is externally fitted by the outer peripheral surface of the rear-end side of the gas sensor element 3, and the outer side electrode 3c (connection part 3cp) and the cylindrical part 99 (tip part of it) R ₂ ) is electrically connected.
Of the tubular portion 99, rearward of the front end edge 99af of the second cut-out portion 99a is a rear end _{R 1,} and the leading end side of the distal edge 99af has a tip _{R 2.} Therefore, a separator between the (not shown) and the gas sensor element 3, since the gap in the direction of the axis O (a part of the rear portion R ₁ and the tip R2) is provided, the contact separator directly gas sensor element 3 This prevents the gas sensor element 3 from being transmitted to the separator 111 and the gas sensor element 3 from being damaged.
In addition, the fitting depth of the tubular portion 99 to the gas sensor element 3 is set so that the front end edge 99af is positioned to the rear end from the rear end edge 3e of the gas sensor element 3.

Next, with reference to FIG. 12, the effect by providing the 2nd notch part 99a when pushing the outer side terminal 97 into a gas sensor element with the separator 111 is demonstrated. As in the first embodiment, first, the outer terminal 97 is attached to the separator 111, and then a pressure device (not shown) is used to push the cylindrical portion 99 with a predetermined stroke on the tip-facing surface 111a of the separator 111. The front end portion of the cylindrical portion 99 is externally fitted near the rear end portion of the gas sensor element 3 (the portion where the outer electrode is formed). At this time, the tubular portion 99, while fitted to the gas sensor element 3 at the tip R _2, the rear end R ₁ is unmated.
Then, in this embodiment, the tip R ₂ is expanded, the tip R ₂ and the rear portion R ₁ is separated by the second cut-out portion 99a, a second cut-out portion 99a is not formed neck It is connected only at the part 99n. Therefore, the diameter is less likely to occur rear portion R ₁ by reaction of enlarged diameter of the distal end portion R _2. That is, the front end R ₂ can be expanded in diameter without being affected by the rear end R ₁ , and when the front end R ₂ is fitted to the gas sensor element 3, the front end R ₂ is a parallel cylinder. The gas sensor element 3 is kept in close contact with the gas sensor element 3.

In the second embodiment, although the effect of reducing the contact area between the forward-facing surface 111a of the rear end face 99b and the separator 111 of the cylindrical portion 99 is not, as described above, the rear end R ₁ diameter also, its deformation is no problem because hardly transmitted to the distal end R _2.
Further, in the second embodiment, if the rear end than the second cut-out portion trailing edge rear edge 3e of the gas sensor element 3 of 99a, the rear end portion R ₁ via the neck 99n tip no problem since it is separated from the R _2. That is, the leading edge 99af of the second notch 99a does not necessarily have to be inserted deeper than the trailing edge 3e of the gas sensor element 3, so that the insertion depth does not have to be adjusted strictly, and productivity is improved. To do.

As described above, the front end R ₂ and the rear end R ₁ are separated in the axial direction O by the second notch 99 a, and therefore the front end R ₂ of the cylindrical portion 99 is separated from the gas sensor element 3 by the separator 111. Even when the rear end R ₁ is reduced in diameter, the tip end R ₂ is kept in a parallel cylindrical shape and is in close contact with the outer surface of the gas sensor element 3. And the electrical connection between the cylindrical portion 99 and the outer electrode 3c is ensured. In addition, since the pressing by the separator 111 may be performed once, the productivity is excellent.
Further, the vibration of the vehicle or the like to which the gas sensor 100 is attached is transmitted from the outer cylinder 40 through the separator 111 and the outer terminal 91 to the contact point between the cylindrical portion 99 and the outer electrode 3c of the gas sensor element 3. Is transmitted only from the neck portion 99n, the contact area between the tubular portion 99 and the separator 111 is reduced, and the vibration transmitted from the separator 111 to the tubular portion 99 is reduced, so that the electrical connection of the contact is difficult to be disconnected.

FIG. 13 is a top view of FIG. 10 viewed along the axial direction O. FIG. As described above, the total length L ₁ = L ₁₁ + L ₁₂ is equal to the slit M and the midpoint C of the cylindrical portion 99 with respect to the circumferential lengths L ₁₁ and L _{12 of} the second cutout portions 99a. it is the circumferential length L ₂ or more. In this way, it is possible to shorten the circumferential length of the neck 99n (see FIG. 12) to less than half of L _2, the rear end R ₁ is recoil tip R ₂ is expanded Is more difficult to communicate.
Further, the circumferential lengths L ₁₁ and L _{12 of} each second notch 99a are not less than ½ of the circumferential length L ₂ between the slit M and the middle point C. In this way, it may increase the length of each second cut-out portion 99a, since the circumferential length of the neck 99n can be shortened to less than half of L _2, the tip portion R ₂ less likely to be further transmitted recoil to diameter is the rear portion R _1.
In FIG. 13, a length ½ of the length L ₂ is represented by L ₃ . The position of the slit M which is the origin of the length L ₂ is a circumferential direction of the center of the slit M, the position of the midpoint C is linear Y is cylindrical portion which passes through the center position and the cylindrical portion 99 of the slit M The position intersects with 99.

FIG. 14 is a modified example of the outer terminal in the second embodiment.
The outer terminal 197 of FIG. 14 has the same configuration as the outer terminal 91 except that the cylindrical portion 199 has only one second cutout portion 199a, and thus the description of the same portion is omitted. The second notch 199a is cut from one end of the slit N along one of the radial directions to the midpoint C to reach approximately 3/4 of the cylindrical portion 197.

FIG. 15 is another modification of the outer terminal in the second embodiment.
The outer terminal 297 in FIG. 15 has the same configuration as that of the outer terminal 91 except for the cylindrical portion 299, and the description of the same portion is omitted. Similar to the cylindrical portion 99 of FIG. 10, the cylindrical portion 299 has two second cutout portions 299 a that communicate with the slit N in the radial direction. Each second notch 299a has the same position in the axial direction O, but extends to the opposite side in the radial direction across the slit N. Further, like the cylindrical portion 99, the two first cutout portions 93a are arranged with the midpoint C as viewed in the axial direction O.
On the other hand, two arm portions 299w parallel to a straight line Z connecting the slit M and the midpoint C are formed on the rear end side from the second cutout portion 299a, and when the cylindrical portion 299 is pressed by the separator 111, The arm portion 299w comes into contact with the separator 111.
Incidentally, the circumferential length L ₁₁ of the second cut-out portion 299a is defined by the length of the cylindrical body of the tip portion than the second cut-out portion 299a.

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 and second cutouts is not limited as long as one or more are formed, and the shape of the cutout 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 3c Outer electrode 3e Rear end edge of gas sensor element 3s Element body 91, 97, 197, 199 Outer terminal 93, 99, 199, 299 Cylindrical part 93e, 99e Rear end edge of cylindrical part 99f of cylindrical part Tip edge 93a First notch 99a, 199a, 299a Second notch 100 Gas sensor 111 Separator 111s Separator tip facing surface C Midpoint facing the slit O Axial direction M Slit L ₁ Circumferential direction of the second notch Total length L ₁₁ , L ₁₂ The circumferential length of each second notch L ₂ The circumferential length between the slit ₂ and the midpoint

Claims (8)

A gas sensor element having a bottomed cylindrical element body that extends in the axial direction and whose tip is exposed to the gas to be measured; and an outer electrode provided on the outer surface of the rear end from the tip of the element body;
A cylindrical portion that surrounds the rear end portion of the gas sensor element in the radial direction at its front end portion and is electrically connected to the outer electrode, the slit extending in the axial direction from the front end edge to the rear end edge An outer terminal provided with a cylindrical portion that is expanded in diameter by elastic force when it is externally fitted to the rear end portion of the gas sensor element.
A gas sensor provided with a separator whose own tip-facing surface is in contact with a rear end surface of the cylindrical portion, and the front end portion of the cylindrical portion is fitted on a rear end portion of the gas sensor element,
A gas sensor provided at a rear end portion of the tubular portion with a first cutout portion that is connected to a rear end edge and is notched in an axial direction toward a front end side.   The gas sensor according to claim 1, wherein a plurality of the first cutout portions are provided intermittently in a circumferential direction of a rear end portion of the cylindrical portion.   When the cylindrical portion is viewed along the axial direction, when the slit is divided into three regions at intervals of 120 degrees starting from the slit, the first notch portion of the cylindrical portion facing the slit The gas sensor according to claim 1, wherein the gas sensor is disposed at least in a region including a midpoint.   When the cylindrical portion is viewed along the axial direction, the first cutout portion sandwiches the middle point of the cylindrical portion facing the slit, and the first cutout portion on one side is the The gas sensor according to claim 1, wherein the gas sensor is disposed at least at a position closer to the midpoint than the slit.   The gas sensor according to any one of claims 1 to 4, wherein the first cutout portion extends in an axial direction over the entire rear end portion of the cylindrical portion. A gas sensor element having a bottomed cylindrical element body that extends in the axial direction and whose tip is exposed to the gas to be measured; and an outer electrode provided on the outer surface of the rear end from the tip of the element body;
A cylindrical portion that surrounds the rear end portion of the gas sensor element in the radial direction at its front end portion and is electrically connected to the outer electrode, the slit extending in the axial direction from the front end edge to the rear end edge An outer terminal provided with a cylindrical portion that is expanded in diameter by elastic force when it is externally fitted to the rear end portion of the gas sensor element.
A gas sensor provided with a separator whose own tip-facing surface is in contact with a rear end surface of the cylindrical portion, and the front end portion of the cylindrical portion is fitted on a rear end portion of the gas sensor element,
Between the front end portion and the rear end portion of the cylindrical portion, a second cutout portion communicating in the circumferential direction from the slit is provided,
The gas sensor in which the total length in the circumferential direction of the second notch is equal to or greater than the circumferential length between the midpoint of the cylindrical portion facing the slit and the slit.   The gas sensor according to claim 6, wherein when the cylindrical portion is viewed along the axial direction, two second cutout portions are provided across the midpoint of the cylindrical portion.   When the cylindrical portion is viewed along the axial direction, the circumferential length of each of the second notch portions is ½ or more of the circumferential length between the slit and the midpoint. The gas sensor according to claim 7.

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