JP5639030B2 - Sensor - Google Patents

Description

  The present invention is a gas sensor such as an oxygen sensor, a NOx sensor, or an HC sensor for detecting a specific gas concentration in a measured gas such as exhaust gas, or a temperature sensor for detecting the temperature of the measured gas. The present invention relates to a sensor including a sensor element for detecting a measurement object.

  Conventionally, various sensors using various sensor elements (hereinafter also simply referred to as elements) having a long plate shape or a rod shape extending in the axial direction, such as gas sensor elements or temperature sensor elements of temperature sensors, have been used. is there. Such a sensor (for example, an oxygen sensor) has, for example, a metal fitting body (main metal fitting) that is formed in a cylindrical shape with a screw portion that is attached to an exhaust gas pipe of an engine. In this device, the sensor element is protruded from the front end of the metal fitting body at the front end side of the sensor element. The element is fixed to the main body so that the rear end portion protrudes from the rear end side of the metal fitting main body. Such an element is arranged in a metal fitting body or a cylindrical body (metal cover) fixed coaxially behind the metal fitting body. In such a sensor, normally, the electrode terminals for taking out the detection output and the heaters formed on the elements are energized on both surfaces facing each other at the rear end portion of the element (in the abdominal position). A plurality of electrode terminals including the electrode terminals (hereinafter also simply referred to as electrodes) are provided, for example, with an insulation interval in the width direction (lateral direction) of the element.

  Each of these electrode terminals and the terminal fitting connected to the tip of the lead wire drawn out of the sensor are electrically connected. Conventionally, such a terminal connection structure is as follows. It has been known. That is, a portion near the rear end of the element is press-fitted between the press contact portions of the respective terminal fittings that are held in the insulating member formed in a cylindrical shape and are held in an opposing arrangement. The pressure contact portion is brought into pressure contact with the electrode terminal of the element by its own spring property. That is, in such an insulating member (also referred to as a separator), the terminal metal and the cylindrical body (metal cover) are secured by using an insulating member that surrounds the terminal metal as well as ensuring electrical connection between the terminal metal parts. And so on, to ensure electrical insulation. However, in this case, at the time of the press-fitting, the electrode terminal (hereinafter also referred to as an electrode) of the element is strongly rubbed at the press-contact portion of the terminal fitting. For this reason, if the electrode terminal is made of a metallized layer, it will be scraped off, resulting in unstable electrical connection or damage due to the resistance (press-fit resistance) at the time of press-fitting. There was a thing.

  In order to solve such a problem, the insulating member is divided into two parts (consisting of a pair of insulating members), and the terminal fittings are arranged so that the terminal fittings are interposed between the two insulating members. The part near the rear end of the element is arranged so as not to be press-fitted between each other, and then both insulating members are closed, and the element is sandwiched between the two insulating members via the terminal fittings. Terminal connection structures are known (see Patent Document 1 (FIGS. 1 and 3), Patent Document 2 (FIG. 8)). In this terminal connection structure, both the insulating members are closed (matched) after the element is arranged, so as to be sandwiched as described above, and the terminal fitting is pressed against the electrode of the element. Therefore, since the sensor element is not press-fitted as in the above prior art, problems such as rubbing of the electrode terminals are solved.

  By the way, each insulating member disclosed in FIG. 3 of Patent Document 1 that constitutes such a terminal connection structure, when both of them are positioned and closed, is in contact with each other, and at each side edge portion. The formed convex part and concave part (or groove) are configured to be fitted. Specifically, when both of them are closed, each insulating member has a convex portion at one side edge portion and a concave portion at the other side edge portion, and the insulating member itself is raised. It is formed in a shape or depression. Thereby, the convex part and recessed part of the mutually insulated insulation member which are closed are comprised so that it may fit in each site | part near a side edge. On the other hand, in each insulating member disclosed in FIG. 8 of Patent Document 2, the convex portion (second positioning portion) is formed in a protruding shape by the insulating member itself, but the concave portion is formed from each insulating member itself. It does not comprise only the raised part (third positioning part). That is, in this case, the wall (wall surface) of the raised portion (third positioning portion) and the portion bent toward the tip of the terminal fitting assembled to the insulating member (the lateral direction forming the bent portion) And the edge of the L-shaped portion formed by the vertical portion at the tip thereof) and the concave portion described above are formed.

Japanese Patent Laid-Open No. 11-248671 JP 2009-115784 A

  The concave portion in each insulating member disclosed in FIG. 3 of Patent Document 1 is a space between two protruding portions that protrude from the side edge portion of each insulating member at a distance from each other (the tip of the two protruding portions). Between the opposite wall surfaces). And this recessed part has shown the structure which notched so that one protruding part formed so that it might extend along the front and rear in the part near a side edge might cross | intersect at the space | interval which a convex part enters in the intermediate part. For this reason, when the two insulating members are closed and positioned, and the convex portions of the insulating members are fitted into the concave portions of the opposing insulating member, relative movement is restricted in the front-rear direction. The movement is restricted in the lateral direction with respect to the front-rear direction (the direction in which both insulating members are closed, that is, the lateral (left-right) direction with respect to the front-rear direction in a virtual plane perpendicular to the direction in which the sensor element is sandwiched). Absent. That is, when one insulating member receives an external force in the lateral direction with respect to the other insulating member, the fitting can be easily moved in the lateral direction by the external force. Thus, the positioning state cannot be stably maintained only by closing the two insulating members and sandwiching the element. For this reason, in order to assemble and close the terminal fitting to the insulating member and maintain the positioning state, it is necessary to fix (or temporarily fix) the two insulating members so as to be sandwiched by a pressing spring or the like. However, even if it is fixed in such a manner, it is not easy to stop the lateral movement (occurrence of lateral displacement) depending on the external force acting on the structure. That is, with such a pair of insulating members, there are difficulties in positioning and closing, and subsequent handling until assembly of the sensor. Further, lateral displacement may occur due to external forces such as vibration and impact that are received in the process of being mounted on an automobile and used after being assembled as a sensor.

  On the other hand, in each insulating member disclosed in FIG. 8 of Patent Document 2, with the above-described configuration, both the insulating members are closed, and the convex portion and the concave portion are fitted. For this reason, when both insulating members are closed, one insulating member leads to the other insulating member along a plane (virtual plane) perpendicular to the closing direction (direction in which the sensor element is sandwiched). , Left and right (horizontal), and slanting directions.

  However, in such a case where each insulating member disclosed in FIG. 8 of Patent Document 2 is closed and positioned, the formation of the concave portion into which the convex portion (second positioning portion) of the insulating member forming the counterpart is fitted, The edge of the L-shaped part of the terminal fitting assembled to the insulating member is used. For this reason, such a recessed part has low shape retaining property of the recessed part itself based on the displacement and deformation of the terminal fitting and the occurrence of minute backlash. Thereby, when the convex part of the insulating member which makes the other party is fitted in such a concave part, there exists a problem that the stability of positioning by the fitting is low. Moreover, in this case, since the terminal fitting also forms a recess, it is necessary to assemble the terminal fitting to the insulating member while taking into account the formation of the recess, and accordingly, the assembly work becomes complicated accordingly. There is also a problem that it takes time and effort.

  The present invention has been made in view of the above problems, and when the convex portions of each pair of insulating members are fitted in the concave portions of the opposing insulating member and both insulating members are closed, Further, when both insulating members sandwich the element via the terminal fitting, one insulating member is imaginary perpendicular to the direction of closing both insulating members (the direction in which the element is sandwiched) with respect to the other insulating member. Not only does it not move freely in any direction along the plane, but also the shape retention of the recess itself, instability of positioning due to its fitting, and the complexity of assembling the terminal fitting to the insulating member, etc. It is an object of the present invention to obtain the above-mentioned fitting without any problem.

According to the first aspect of the present invention, there is provided a plate-like or rod-like sensor element having a detection portion on the front end side directed to the measurement object and having electrode terminals on both opposing surfaces of the rear end portion. The sensor element is disposed through the inside of the metal fitting body, the rear end portion of the sensor element protrudes rearward from the rear edge of the metal fitting body, and is connected to each electrode terminal at the tip of the lead wire that is led out to the outside. A sensor in which electrical connection is maintained by pressing each terminal fitting to be connected,
The sensor element has a pair of insulating members made of an electrical insulating material arranged so as to sandwich the sensor element from both surface sides via terminal fittings, respectively.
In addition, each insulating member, when both of them sandwich the sensor element from the both surface sides via the terminal fitting, respectively, the insulating member that forms a counterpart facing each other, and the side edges that straddle the sensor element. The convex part formed in the part and the concave part are opposite to each other, and the convex part is provided on one side edge part and the concave part is provided on the other side edge part. In the sensor
When the convex portion is fitted into the concave portion of the other insulating member and the both insulating members sandwich the sensor element from the both surface sides via terminal fittings, the concave portion is the convex portion of the convex portion. The protrusion and the convex portion so that the movement is restricted and the movement of the one insulating member is restricted in any direction along a virtual plane perpendicular to the direction of sandwiching the sensor element with respect to the other insulating member. The concave portion is formed, and both the convex portion and the concave portion are integrally formed by the insulating member itself.

According to a second aspect of the present invention, the insulating member has a protruding portion protruding in the sandwiching direction at any one of the side edge portions, with a distance from the rear.
The sensor according to claim 1, wherein the recess is between the raised portions.
According to a third aspect of the present invention, the insulating member has a raised portion that protrudes in the sandwiching direction at either one of the side edge portions.
The sensor according to claim 1, wherein the concave portion is a hole formed in a depressed shape at the top of the raised portion.
The invention according to claim 4 is the sensor according to any one of claims 1 to 3, wherein the pair of insulating members is a common component.

According to a fifth aspect of the present invention, the pair of insulating members are arranged so as to sandwich the sensor element from both surface sides via terminal fittings, and both the insulating members are disposed behind the fitting main body. It is clamped by a clamping member having spring property in the arranged cylindrical body,
When the cylindrical body is crimped to a reduced diameter, the sandwiching member is deformed, and the terminal fitting is pressed against the electrode terminal of the sensor element to maintain electrical connection. It is a sensor of any one of Claims 1-4 characterized by the above-mentioned.

  In the present invention, with the above configuration, when the convex portion of each insulating member is fitted into the concave portion of the opposing insulating member, both insulating members sandwich the element via the terminal fitting (both insulating materials). When one member is closed), the movement of one insulating member is restricted in any direction along a virtual plane perpendicular to the direction in which the element is sandwiched with respect to the other insulating member (the direction in which both insulating members are closed). Has been. Moreover, what is important in the present invention is that both the convex portion and the concave portion are integrally formed by the insulating member itself. That is, in the present invention, unlike the prior art, the terminal fitting is not used for forming the recess for fitting in the insulating member. For this reason, there is no problem in the shape retention of the concave portion, and the two closed insulating members are not displaced from each other due to the displacement or movement of the terminal fitting. As a result, when a pair (two splits) of insulating members are positioned and the protrusions and recesses are fitted to each other and closed, they are closed and are also in a fitted state after the element is clamped via the terminal fitting There is no instability. Furthermore, since it is not necessary to consider the formation of the recess in the assembling work of the terminal fitting to the insulating member, the assembling work is not complicated. In the present invention, that the movement is restricted in any direction means that the movement cannot be freely made in any direction (front and rear, left and right, and diagonal directions).

  As described above, according to the present invention, the terminal fitting can be assembled without complicating the work of assembling the terminal fitting to the insulating member. And since there is no instability in the process of closing the pair of insulating members after the assembly, and the fitting between the concave portion and the convex portion by both after the closing, both the insulating members are mutually connected along the virtual plane. There is no deviation. Therefore, vibrations and shocks that occur during the process of handling assembled parts (work-in-process) that include both insulating members, and assembling as a sensor and then being used in an automobile, up to the final assembly as a sensor. Even with an external force such as the above, high stability is maintained such that no deviation occurs. For this reason, the reliability of the electrical connection of an element and a terminal metal fitting is improved.

  In the present invention, the convex portion and the concave portion may each be one or more. In the present invention, when the convex portion of each insulating member is fitted in the concave portion of the opposing insulating member and both insulating members are closed in a direction to sandwich the element, one insulating member is the other The concave portion may be formed so as to restrict (or constrain) the movement of the convex portion so that the movement of the insulating member is restricted in any direction along the virtual plane. Therefore, it is clear that the concave portion may be a hole for fitting the convex portion, but is not limited thereto. Rather, in the case of being made of brittle ceramic, in order to avoid the generation of a relative thin portion, the concave portion is formed between the raised portions formed so as to be raised at a distance from each other. Is preferred. In this case, the shape and structure may be set so that at least one of the opposing wall surfaces (wall portions) or the bottom surface (bottom portion) of both protruding portions restricts or restrains the movement of the convex portion. . That is, when the convex portions are prevented from moving in the front-rear direction on the opposite wall surfaces of the two ridges forming the concave portion, one insulating member is relative to the left-right direction (lateral direction) with respect to the front-rear direction. For example, the wall surface may be formed so that the insulating member does not move when an external force is applied. More specifically, a part (engagement part) that stops the convex part of the mating counterpart insulating member from moving in the left-right direction at a part near both side edges of the opposing wall surface forming the concave part, that is, viewed from the closed surface side. When the V-shaped wall is concave, the convex portion may be formed so as not to move freely by contacting or engaging the concave V-shaped wall with external force in the lateral direction.

  In addition, when making the said recessed part into a hole, it is preferable to form in the depressed shape in the top part (top surface) of the protruding part formed so that it may protrude. The hole only needs to have a wall that restricts or restricts the outer peripheral surface of the convex portion, and may be a circular or polygonal hole when viewed from the closed surface side. Moreover, the hole may penetrate. Thus, in the present invention, the concave portion or the convex portion can be embodied as having an appropriate shape and structure. In the present invention, the two insulating members that form a pair are preferably made of common parts (same parts having the same dimensions and the same shape). This is because if the common component is used, only one (type) of component type is required, and the manufacture and management thereof are facilitated. The insulating member is preferably made of ceramic from the viewpoints of heat resistance and durability. Therefore, the fitting with the concave portion or the convex portion is a gap fitting, but there is no problem in fitting. Thus, it is preferable that the gap fit is as small as possible.

The longitudinal cross-sectional view of the embodiment which actualized the sensor of this invention. The enlarged view of the A section of FIG. BB sectional drawing of FIG. The exploded perspective view seen from the rear end side of the upper half assembly of the sensor of this example. FIG. 5 is an enlarged view of the C part in FIG. 4 including elements. FIG. 6 is a further enlarged view of only the insulating member in FIG. 5. The figure which looked at the insulating member of FIG. 6 from the closed surface side. The perspective view which looked at only the insulating member in FIG. 5 from the front end side. FIG. 6 is an explanatory perspective view in which both insulating members in FIG. 5 are closed (closed in a direction in which an element is sandwiched). The perspective view seen from the front end side explaining the state which assembled | attached the terminal metal fitting to the insulating member. The perspective view for description which closed both the insulation members which assembled | attached the terminal metal fitting, and the perspective view of a clamping member. FIG. 4 is a longitudinal sectional view for explanation before assembling the upper half assembly and the lower half assembly of the sensor of this example. The longitudinal cross-sectional view before the crimping process after assembling | attaching an upper half assembly and a lower half assembly from the state of FIG. The expansion perspective view seen from the back end side explaining example-1 of an insulating member. The figure which looked at the insulating member of FIG. 14 from the closed surface side. The expansion perspective view seen from the rear end side explaining the other example-2 of an insulating member. The perspective view for description which closed both the insulation members of FIG. The expansion perspective view seen from the rear end side explaining the other example-3 of an insulating member. The perspective view for description which closed both the insulation members of FIG. The center cross-sectional view of the front-back direction in both the insulation members of FIG. 18, and the XX sectional view of FIG.

  An embodiment (first embodiment) embodying the sensor of the present invention will be described in detail with reference to FIGS. However, the present embodiment is embodied in an oxygen sensor that detects the oxygen concentration in the exhaust gas. Therefore, the entire gas sensor 101 (hereinafter also referred to as a sensor) 101 will be described in detail first. In the figure, reference numeral 101 denotes an oxygen sensor, which is a sensor element formed mainly of a plate-like or rod-like ceramic having a rectangular cross section inside a cylindrical metal fitting body 11 (hereinafter also simply referred to as the main body 11). 21 is fixed airtight. This element 21 is a long element provided with a detection part (not shown) 21a on the tip side (the lower side in the figure) directed toward the measurement object. The inner peripheral surface of the metal fitting body 11 is formed in a stepped cylindrical shape having a concentric lower side (front end side) and a small diameter, and a screw 12 for fixing to the exhaust pipe of the engine is provided near the lower end of the outer peripheral surface. Is formed. Inside the main body 11 and outside the sensor element 21, airtight holding and fixing means for holding the element 21 in an airtight manner is provided in a filling manner. In this airtight holding and fixing means, a holder 31 made of alumina from below and sealing materials (talc in this example) 32 and 33 are arranged on a lower step inside the main body 11. A fixing plate 35 is disposed on the sealing material 33, and is a thin wall continuous with a cylindrical portion 15 for externally fitting and fixing a cylindrical body 81 to be described later at a portion near the rear end of the main body 11. The element 21 is fixed to the inner side of the metal fitting body 11 in an airtight manner by bending the caulking cylindrical portion 16 inwardly and compressing the caulking cylindrical portion 16 toward the distal end side, and compressing the internal sealing materials 32 and 33 and the like. The inner center of the holder 31 or the like is a rectangular (rectangular) hole whose cross section corresponds to the cross section of the element 21, and the element 21 is fixed coaxially in the main body 11.

  In the element 21 fixed as described above, the front end side (lower side in FIG. 1) where the detection portion 21 a is provided protrudes a predetermined amount (length) from the front end of the main body 11, and the rear end portion 23 is formed on the bracket main body 11. A predetermined amount (length) is projected from the rear end. In this embodiment, the tip of the element 21 protruding from the tip of the metal fitting body 11 (detection unit 21a) is a protector (protective cover) having a double structure provided with a plurality of holes so as to surround the periphery. ) 18 is fixed to the tip of the main body 11. However, the inner protector is disposed on the inner step of the front end of the main body 11 so that the rear end flange is locked. Further, the large diameter portion 19 formed in a projecting shape on the outer periphery in the middle portion of the main body 11 in the axial direction (center axis) G is a screw 12 of the main body 11 when the sensor 101 is attached to the exhaust pipe (not shown). It is the polygon part for screwing in when screwing in. And the gasket 20 for sealing is attached to the lower surface of this polygon part.

  Here, the element 21 thus fixed in the main body 11 will be described. In the element 21 used in this embodiment, an electrode terminal 25 is formed at a rear end portion 23 protruding from the rear end of the main body 11. The element 21 is in the form of a band plate, has a wide surface, and has two electrode terminals 25 arranged side by side on both surfaces (hereinafter also simply referred to as a surface or a surface) 26 in a positional relationship between the stomach and the back. (Refer to the two-dot chain line shown in FIG. 5. Only the surface 26 on one side is shown in FIG. 5). These electrode terminals 25 are for taking out a detection output from the detection unit 21 a and for applying a voltage to a heater (not shown) formed in the element 21, both of which are along the longitudinal direction of the element 21. It has an elongated rectangle. Each electrode terminal 25 is formed by simultaneously firing a printed metallized paste together with the ceramic element 21. Further, as will be described in detail later, the sensor 101 of this embodiment has a lower subassembly 100 in which the element 21 is fixed in the main body 11 as shown in FIG. The subassembly 102 is assembled immediately before the final manufacturing process, and then manufactured through a necessary process such as caulking.

  Now, with respect to the parts other than the lower half assembly 100 of the sensor 101 described above, that is, the parts corresponding to the parts forming the upper half assembly 102 in FIG. 12, based on FIGS. explain. That is, four lead wires 61 are drawn out from the rear end of the cylindrical body 81, which is the upper end of the sensor 101 in the drawing, to the outside (upward in the drawing). Terminal fittings 51 are respectively attached to the respective distal ends (core wires) by caulking (see FIGS. 1 and 5). In this example, the cylindrical body 81 has a different diameter cylindrical shape having a small diameter cylindrical portion 83 on the upper end side in the figure, and the tip (lower end in FIG. 1) side is a portion closer to the rear end of the main body 11 as described above. And is fixed by caulking or welding.

  Here, each terminal fitting 51 will be described. The terminal fittings 51 are spaced in the width direction on the side of each surface 26 so as to be pressed and connected to the two electrodes 25, 25 formed side by side on each surface 26 of the element 21. Are arranged. As shown in FIG. 5, each terminal fitting 51 is made of a flat plate material and extends downward from a barrel portion 52 that is crimped and fixed to the core wire by caulking. However, each of the surfaces 26 has a crank portion 52b bent sideways so that the left and right terminal fittings 51 are close to each other. It is symmetrical on the side. And at the front-end | tip of the crank part 52b, it has the bending part 53 bent by the axis line G side, and follows this bending part 53 in the linear part 55 extended straightly downward, and the lower end of the linear part 55 And a bent piece 57 that is bent so as to face the element 21 side (axis G) side and the opposite side (outside).

  Such a terminal fitting 51 is provided with a protruding portion 59 protruding toward the axis G side on the surface facing the axis G side of the intermediate portion of the straight portion 55, and the protruding portion 59 is the above-described portion. It is formed so as to be in spot contact with the electrode 25 on each surface 26 of the element 21. In this example, two of these four terminal fittings 51 are arranged on each surface 26 side of the element 21. Then, a pair of block-like insulating members (for example, made of alumina) 71 constituting the main part of the present invention, which is arranged so as to sandwich the element 21 from both surfaces 26 via the terminal fittings 51, respectively. , 71 is sandwiched between the element 21 via the terminal fitting 51 and the projection 59 is pressed against each electrode 25 on both surfaces 26 thereof.

  Further, as shown in FIGS. 2, 10, 11, etc., each terminal fitting 51 has its bent portion 53 along the upper end of the insulating member 71 and the straight portion 55 on the closing surface 72 of the insulating member 71. The bent piece 57 is assembled to the insulating member 71 along the lower end of the insulating member 71 as shown in FIG. Details of the assembled state and the insulating member 71 will be described later. In this way, the terminal fitting 51 is arranged so as to sandwich the sensor element 21 from both surface sides.

  In this example, the pair of insulating members 71 that are closed in this way and sandwich the element 21 via the terminal fitting 51 are provided on the outside thereof as shown in FIGS. An annular clamping member 91 is arranged so as to surround the insulating member 71. The sandwiching member 91 includes an inward projecting portion 93 projecting inward so that two opposing portions at 180 degrees are close to each other, and an inner surface (plate surface) 92 of the inward projecting portion 93 is The outer surface 78 of both insulating members 71 is sandwiched by its own spring property. The sandwiching member 91 is disposed behind the metal fitting body 11 on the inner side of a cylindrical body 81 (cylindrical body) disposed and fixed coaxially therewith. And the site | part 82 corresponding to the clamping member 91 among the direction of the axis line G in the cylindrical body 81 is crimped by the diameter-reduced shape in the circumferential direction, On the inner peripheral surface of the cylindrical body 81 of the crimping site | part 82, By deforming the sandwiching member 91 so as to compress it toward the axis G, the opposing inward projecting portions 93 sandwich both the insulating members 71 from the outer side surface 78.

  Note that, at the stage where the sandwiching member 91 is simply disposed on the insulating member 71, the protruding portion 59 of the terminal fitting 51 is not pressed against the electrode terminal 25 of each surface 26 of the element 21, and the gap is maintained. Or the dimension between the inward protrusions 93 facing each other of the sandwiching member 91 itself is set so as to be loosely contacted. When this is seen from the axis G side, the pinching member 91 has a so-called contour shape of a peanut shell, and the inwardly projecting portion 93 has an outer surface formed in a concave shape on both insulating members 71. (Concave surface) 78 is formed to enter.

  A cylindrical elastic sealing material (seal member made of rubber or the like) 85 is disposed inside the small-diameter cylindrical portion 83 near the rear end (illustrated end) of the cylindrical body 81 constituting the sensor 101. A lead wire 61 fixed to the caulking barrel portion 52 of the terminal fitting 51 is passed through the elastic sealing material 85 at an angular interval when viewed from the direction of the axis G. The elastic sealing material 85 is configured to hold the seal at the rear end of the sensor 101 by compressing the small diameter cylinder 83 at the upper end of the outer cylinder 81 to reduce the diameter. In addition, a filter 40 for taking in outside air having water repellency and hydrophobicity is fitted in the central hole in the rear end portion of the elastic seal material 85. The rear end of the filter support member 41, which is made of an insulating material and has a large-diameter portion 45 on the front end side of the elastic seal member 85 in the central hole at the rear end portion of the elastic seal member 85, forms a cylinder with a different diameter. The small diameter portion 43 on the side is fitted. Then, the rear end facing surface of the small diameter portion 43 is brought into contact with the tip of the filter 40 to support it. In addition, the lead wire 61 is passed through the large diameter portion 45 of the filter support member 41 through the previous through hole. The sensor (assembly) 101 of this example is configured as a whole as described above.

  Next, details of the pair of insulating members 71 and 71 constituting the sensor 101 will be described with reference to FIGS. As described above, the insulating member 71 on each side is in a block shape and has the same (same structure, same dimensions), and generally includes a base (substrate) 70 made of a square plate (thick plate). Yes. Then, when the two are opposed to each other and closed, the convex portions 77b formed in the portions closer to the side edges 76 and 77 and the concave portions 76b are fitted between the opposing insulating members 71. Is formed. That is, each of the opposing insulating members 71 has a protruding portion 77b formed by the insulating member itself at a portion near one side edge 77 that is opposite to each other when the closed surface 72 is positioned facing the base 70. It is formed integrally with the insulating member 71 so as to protrude toward the insulating member 71. At this time, a raised portion 76c from which the insulating member itself protrudes toward the other insulating member 71 is formed integrally with the insulating member 71 at a distance from the other side edge 76, and the A recess 76b is formed between the two raised portions 76c and 76c for receiving and fitting the other-side convex portion 77b.

  More details are as follows. Each insulating member 71 is based on a substantially square or rectangular base body 70, and one of the opposing surfaces (closed surface 72) when both are closed (on the right side in FIG. 7) opposite to each other. A convex portion 77b that protrudes (protrudes) with a certain width and height toward the insulating member 71 that is the opposite party is provided near the side edge 77. However, the top portion 77t of the convex portion 77b is flat. In this example, the convex portion 77b is provided at an intermediate portion in the front-rear direction (the vertical direction in FIGS. 6 and 7) when the insulating member 71 is viewed from the closed surface 72 side (see FIG. 7). In addition, when viewed from the closed surface 72 side, each end in the front-rear direction (vertical direction in FIGS. 6 and 7) of the convex portion 77b is forward (upward in FIG. 7) or rear (in FIG. 7). It forms a square shape that projects in a mountain shape (V shape) toward (downward). That is, among the convex portions 77b, the wall surface 77d that forms each end in the front-rear direction rising from the closed surface 72 is a V wall surface that is convex when viewed from the closed surface 72 side. Thereby, when the insulating member 71 is viewed from the closed surface 72 side, the convex portion 77b has a long hexagonal shape (see FIG. 7 and the like).

  On the other hand, among the insulating members 71, the concave portions 76 into which the convex portions 77b of the opposing insulating members 71 are fitted, as described above, are located near the side edge 76 on the other side (left side in FIG. 7). It is between two raised portions 76c formed so as to be raised with a certain width and height and spaced from each other. The opposing wall surfaces 76d and 76d of the two raised portions 76c are in contact with the wall surface (V wall surface) 77d formed as the front and rear protrusions of the convex portion 77b of the opposing insulating member 71 (by gap fitting). The convex part 77b is received and fitted, and in the fitted state, the concave part 76 is formed so as to relatively restrict or restrain the movement of the convex part 77b. That is, in this example, the closed surface 72 is formed so that the opposing wall surfaces 76d and 76d of the two raised portions 76c forming the concave portion 76b form a regulating portion (constraint portion) that relatively regulates the movement of the convex portion 77. When viewed from the side, the opposing wall surfaces 76d and 76d form a concave V wall surface (hereinafter also referred to as V wall surface 76d) (see FIG. 7).

  In addition, the height (protrusion height) of the V wall surface 76d in the concave portion 76b is the same as the height of the convex portion 77b. Thereby, when the convex part 77b of each insulation member 71 fits into the recessed part 76b of the other insulation member 71 and the both insulation members 71 are closed, one insulation member 71 is the other insulation member 71. On the other hand, the movement is restricted in the front, rear, left and right directions along a virtual plane perpendicular to the direction in which both insulating members 71 are closed (the direction in which both insulating members 71 sandwich the element). In other words, the insulating members 71 are configured not to move freely in any direction along the virtual plane. That is, from the state of FIG. 6, when both the insulating members 71 are closed as shown in FIG. 9 and the convex portions 77b are fitted in the concave portions 76b, the concave portions 76b of one insulating member 71 are The V wall surface 76d formed as a concave which is an inner surface regulates (restrains) a wall surface 77d formed as a protrusion of the convex portion 77b of the other insulating member 71 (hereinafter also referred to as a V wall surface 77d). Do not move in any direction along a virtual plane (in this example, a plane parallel to the closing surface 72) perpendicular to the direction in which both are closed (the direction of the arrow T in FIGS. 6, 8, and 10). It is configured as follows. In this example, since the wall surfaces 76d and 76d of the recess 76b are only the portions that are opposed to each other, the lateral direction is open to the left and right between the both wall surfaces.

  Thus, by closing both the insulating members 71 facing each other in a direction in which the element 21 is sandwiched, a hole 73 having a substantially rectangular cross section is formed between the two insulating members 71 as shown in FIG. Is formed. In this example, the terminal fitting 51 is assembled in advance in the hole 73 as will be described later, and the rear end portion of the sensor element 21 is disposed. Thereby, the convex part 77b and the recessed part 76b are formed so that the sensor element 21 may be straddled. The closed surface 72 of the insulating member 71 that forms the air holes 73 sandwiched between the convex portions 77b and the concave portions 76b on both sides of each insulating member 71 is a flat surface. It is formed lower than the bottom surface 76t. Further, a portion near the side edge 77 (the front and rear of the convex portion 77b) 77h forming the base of the convex portion 77b is the width of the convex portion 77b and is substantially flush with the bottom surface 76t of the concave portion 76b.

  Further, in this example, in the center in the width direction between the upper end and the lower end of each insulating member 71, the partitioning convex portions 74 b and 75 b are formed in a raised shape at the portions near the left and right side edges 76 and 77. The recesses 74 and 75 are cut (see FIGS. 6 to 8 and the like). As a result, the bent portion 53 at the upper end of the straight portion 55 and the bent piece portion 57 at the lower end of the terminal fitting 21 are fitted into the recesses 74 and 75 cut in this way, and the straight portion 55 is closed. The terminal fitting 51 is assembled to the insulating member 71 along the front and rear (see FIGS. 2, 5, 10, etc.). As a result, the terminal fitting 51 assembled to each insulating member 71 is restricted from moving in the lateral direction and the front-rear direction (vertical direction), and is also prevented from touching between adjacent terminal fittings 51. Have.

  Thus, the sensor 101 of this example having the above-described configuration assembles the upper half assembly 102 described above separately from the lower half assembly 100. This assembly has been outlined above, but the details are as follows. As shown in FIGS. 4 and 5, the elastic seal member 85 fitted with the filter 40 and the through hole of the filter support member 41 are drawn out from the rear end side through the tip of the lead wire 61. The barrel portion 52 of the terminal fitting 51 is crimped to the leading end of the lead wire 61 that has been drawn out. And the linear part 55 of each such terminal metal fitting 51, the bending part 53, and the bending piece part 57 are assembled | attached to the insulating member 71 as mentioned above (refer FIG. 10). The insulating members 71 assembled with the terminal fittings 51 are closed so that the closed surfaces 72 face each other. As shown in FIG. The convex portion 77b of the mating insulating member 71 is fitted into 76b. By this fitting, one insulating member 71 is imaginary plane perpendicular to the other insulating member 71 in the direction in which both insulating members are closed (the direction of arrow T in FIG. 10; the direction in which the element 21 is sandwiched). , It does not move in any of the front, rear, left and right directions.

  Next, in this example, the pinching member 91 having a spring property is externally fitted as shown by a two-dot chain line in FIG. 11 so as to surround both the insulating members 71 thus closed. Then, the inward protruding portion 93 is fitted into the concave outer surface 78 of each insulating member 71. At this stage, the two insulating members 71 are held so as to press the closing surfaces 72 against each other without being separated. On the other hand, both the insulating members 71 do not move in any direction along the virtual plane due to the above-described fitting even before the sandwiching member 91 is fitted. Therefore, both the insulating members 71 incorporating the terminal fittings 51 will not come off even in the process until the clamping member 91 is fitted or after that. Therefore, it is easy to handle both insulating members 71 in the subsequent assembly process.

  In addition, a terminal fitting that is assembled separately as in the prior art is not used to close the pair of insulating members 71 in the direction in which the element 21 is sandwiched and to maintain the desired positioning state. That is, in this example, the fitting state is maintained by the convex portion 77b and the concave portion 76b which are integrally formed as described above by the insulating member 71 itself. For this reason, the conventional assembly work of the terminal fitting to the insulating member 71 is not complicated. Further, even if the terminal fitting 51 is displaced or deformed, or has a slight rattling or movement, the positions of the two insulating members after the fitting are not unstable. As described above, in this example, the pair of insulating members 71 are closed in the direction in which the element 21 is sandwiched, and a desired positioning state can be easily held and continued. Therefore, since the pair of insulating members after the fitting does not shift laterally, assembly until completion of the sensor is facilitated. After that, the sensor is assembled as a sensor through the following steps.

  That is, as shown in FIG. 11, after both insulating members 71 are closed and held in the state by the sandwiching member 91, as shown in FIG. 4, as shown in FIG. 81. Then, the rear end side of the lead wire 61 is pulled, and the small-diameter portion 43 of the filter support member 41 is pushed into the air hole of the elastic seal material 85 to support the filter 40 inside. In this way, as shown in the upper part of FIG. 12, the upper half assembly 102 is obtained that is positioned in the front-rear direction and accommodates each member in the cylindrical body 81.

  Subsequently, separately, the lower half assembly 100 including the above-described element 21 that is assembled and the upper half assembly 102 described above are coaxially arranged vertically as shown in FIG. Then, the rear end portion 23 of the element 21 projecting in the lower subassembly 100 is relatively positioned between the projecting portions 59 of the opposing terminal fitting 51 in the both insulating members 71 accommodating the terminal fitting 51. Insert. At the same time, the distal end portion of the cylindrical body 81 is fitted to the outer peripheral surface of the cylindrical portion 15 at a portion near the rear end of the metal fitting body 11. By doing so, the work-in-process 103 shown in FIG. 13 is obtained.

  Next, in the state shown in FIG. 13, a part 82 (arrow part) corresponding to the sandwiching member 91 among the front and rear positions in the cylindrical body 81 is shrunk as shown by the radial arrow in FIG. The inner pinching member 91 is compressed into a reduced diameter by caulking into a diameter. By doing so, the opposing inward projecting portions 93 strongly sandwich the two insulating members 71 between them. As a result, the sandwiching member 91 including the inward projecting portion 93 is deformed, and the projecting portion 59 of the straight portion 55 of the terminal fitting 51 between the insulating members 71 closed in the direction of sandwiching the element 21 The electrode 25 is pressed against the electrode 25 in such a manner as to be pressed, and electrical conduction therebetween is maintained. After this crimping, it is preferable that a minute gap S remains between the two insulating members 71 as shown in FIG. In FIG. 13, for example, a portion (arrow portion) that is fitted to the outer peripheral surface of the cylindrical portion 15 near the rear end of the metal fitting body 11 in the front end portion of the cylindrical body 81 is caulked in the circumferential direction. All-around laser welding. Further, the outer peripheral surface portion (arrow portion) of the small-diameter cylindrical portion 83 of the cylindrical body 81 corresponding to the elastic sealing material 85 is caulked in a reduced diameter shape to ensure a seal. By doing so, the sensor 101 of FIG. 1 is obtained.

  The sensor 101 of this example is finally assembled through such a process. As is apparent from the above, the convex portions 77b of the pair of insulating members 71 are concave portions of the opposing insulating member. When both the insulating members 71 are closed in the direction in which both the insulating members 71 are sandwiched between the elements 21 by being fitted to 76b, one of the insulating members is any one of the front, rear, left and right, etc. It does not move in the direction. Moreover, the insulating member 71 itself is integrally formed with the convex portion 77b without using a terminal fitting as in the prior art for forming the concave portion 76b. Therefore, there is no instability of positioning due to the shape retention of the recess as in the prior art, and the fitting between the projection and the recess, and the insulating member 71 does not move relative to each other even when subjected to external force such as vibration. There is no decrease in the reliability of the electrical connection. Further, the assembly work of the terminal fitting 51 with respect to the insulating member 71 is not complicated.

  Note that, as in the previous example, the recess 76b in the insulating member 71 is between two raised portions 76c that protrude at a distance from the front side of the insulating member 71, and a convex portion is provided between the opposing wall surfaces. When the movement of 77b is restricted, the concave portion 76b as viewed from the closed surface 72 side, that is, the two raised portions 76c face each other, as in Alternative-1 of the insulating member 171 shown in FIGS. The wall surface may be changed from the V wall surface of the previous example as a circular arc wall surface 76d that is concave, and a circular wall surface 77d that is convex at the front and rear ends of the corresponding convex portion 77b. Further, as indicated by a broken line in FIG. 15, the concave wall 76b on the left side as viewed from the closed surface 72 side, that is, the arc wall (or V wall surface) in which the opposite wall surfaces of the two raised portions 76c are convex. ) 76d, and it is obvious that the arc wall surface (or V wall surface) 77d may be a concave wall surface at the front and rear ends of the convex portion 77b on the right side of the figure. 14 and 15 are the same as those of the insulating member 171 of the above example (FIGS. 6 and 7), and therefore the same parts are denoted by the same reference numerals. stop. The same applies to the following examples.

  That is, in the present invention, when the convex portion of each insulating member is fitted in the concave portion of the opposing insulating member and both insulating members are closed in a direction to sandwich the element, one insulating member is The concave portion relatively restrains the convex portion so that the movement of the other insulating member in any direction along the virtual plane is restricted, and the convex portion and the concave portion are both insulated. The member itself may be integrally formed. Therefore, as described above, the shape of the front and rear ends of the concave portion and the convex portion when viewed from the closed surface can be an appropriate shape even when both sides of the concave portion are open as in the above examples. is there. Further, for example, in FIG. 15, regarding the convex portion or the concave portion when viewed from the closed surface 72 side, only one of the front and rear ends is an arc wall surface (or V wall surface), and the other end is in the left-right direction. It is good also as a wall surface which makes a straight line (lateral direction).

  Next, another example-2 of the insulating member constituting the sensor of the present invention will be described with reference to FIGS. However, in this example, the convex portion 77b of the insulating member in the above example is a convex portion 277b made of a cylindrical boss that is circular when viewed from the closed surface 72 side of the insulating member 271, and the concave portion 76b is the convex portion 277b. Is a recess 276b composed of a hole (independent hole) that fits in a minute gap. Therefore, it should be called a modification. That is, the circular convex portion 277b is fitted with a minute gap in the raised portion 76c where the concave portion 276b is raised with a predetermined width and height along the front and rear at a portion closer to one side edge as viewed from the closed surface 72 side. The only difference is that the raised portion 76c is provided as a circular hole in a recessed shape at the center in the front-rear direction. In this case, when the convex portions 277b of the pair of insulating members 271 that are closed in the direction of sandwiching the elements are fitted into the concave portions 276b of the opposing insulating member 271, the outer wall surface 277d of the convex portion 277b is the concave portion. It is restrained by a cylindrical wall surface (inner peripheral wall surface) 276d forming the inner surface of 276b. Therefore, also in this example that receives such an action, the same effect as the above example can be obtained. In addition, when making a recessed part into an independent hole, it can also be made into a square hole instead of a circular hole, but in that case, when a convex part fits into this recessed part, a movement is controlled inside it. What is necessary is just to form.

  By the way, when the concave portion 276b is a hole whose inner peripheral surface (wall surface) such as a circle is continuous as in the above example, left and right side portions (left and right walls of the hole) of the wall surface (inner wall surface) 276d are open. Instead, as shown in FIG. 16, there is a thin portion. Such an insulating member 271 is preferably made of ceramic from the viewpoint of ensuring heat resistance and the like. On the other hand, a brittle ceramic tends to generate cracks and chips in its thin wall portion. From this point of view, it is preferable to use the above-described first embodiment or another example-1.

  In each of the above examples, when both insulating members are fitted to each other by the convex portion and the concave portion and closed in the direction in which the element is sandwiched, one insulating member extends along the virtual plane with respect to the other insulating member. The inner surface of the recess for restricting movement in any direction was used as a wall surface facing two bulging portions that bulge at an interval in the front and rear, or a wall surface of the hole (inner peripheral wall surface). However, the inner surface of the concave portion only needs to be able to restrain the convex portion of the mating insulating member. Therefore, the part of the concave part that restrains or regulates the convex part of the other party need not be such a wall surface. In order to show an example thereof, an insulating member 371 according to another example-3 will be described with reference to FIGS.

  In this example, the convex portion 377b is formed in a raised shape with a rectangle or a square extending along one side at the front and rear center of the portion closer to one side of the insulating member 371 when viewed from the closed surface 72. Yes. However, the top portion (top surface) 377t of the convex portion 377b forms a V-groove extending backward. That is, when viewed from the closed surface 72, the convex portion 377b in this example has a V-block body in which the top portion 377t has a V-groove extending forward and backward, and is formed in a raised shape in such a manner that the V-groove extends forward and backward. The shape is made.

  On the other hand, when viewed from the closed surface 72 side, the concave portion 376b is between the two raised portions 76c formed so as to protrude at a distance from each other on the other side of the insulating member 371. . However, the opposing wall surfaces 376d of the two raised portions 76c are formed in parallel so that the convex portions 377b can be fitted in contact with the flat wall surfaces 377d which are the respective front and rear ends of the convex portions 377b. A wall surface 376d is presented. On the other hand, the bottom portion (bottom surface) 376t between the two raised portions 76c has a triangular mountain shape that continues in the same cross section so as to fit into the V groove of the top portion (top surface) 377t of the convex portion 377b. Thereby, when the convex part 377b which makes the V block body of the insulating member 371 which is the other party is fitted in the concave part 376b, the front and rear wall surfaces 377d of the convex part 377b form the concave part 376b, and the distance between the front and rear is increased. The movement in the front-rear direction is restricted by the opposing wall surfaces 376d of the two raised portions 76c. Further, in the left-right direction and the oblique direction as viewed from the closed surface 72 side, the triangular mountain-shaped portions forming the bottom portion 376t of the concave portion 376b that fit into the V-groove of the top portion 377t of the convex portion 377b move each other. regulate. Therefore, also in the insulating member 371 of the third example, the same effect as each of the above examples can be obtained.

  That is, in the present invention, when the convex portion of each insulating member is fitted in the concave portion of the opposing insulating member and both insulating members are closed in a direction to sandwich the element, one insulating member is The protrusions and the recesses only need to be formed so that the movement of the other insulating member is restricted in any direction along the virtual plane. The shape or structure of the convex portion and the concave portion can be embodied as appropriate in the case where they are integrally formed from the insulating member itself. In each of the above examples, the pair of insulating members are made of common parts. However, the two insulating members can be embodied as having different shapes and structures.

  In the sensor exemplified above, in order to maintain the closed state of both insulating members, a separate annular sandwiching member having a spring property is used to sandwich both insulating members in a closed form. Instead of this, for example, the insulating member may be temporarily fixed or bonded to hold the both insulating members in a closed state, and the both insulating members may be sandwiched between the cylindrical bodies themselves. . Therefore, when the pressure-contact of the terminal fitting against the electrode of the element by sandwiching both insulating members depends only on the deformation by caulking the cylindrical body from the outside, an independent sandwiching member is unnecessary. Further, even if an independent clamping member is used, it may be clamped by a member made of a U-shaped spring instead of an annular shape.

  Further, the terminal metal fitting, the insulating member, and the element constituting the sensor of the present invention are not limited to those described above, and can be embodied as having an appropriate configuration. That is, the present invention can be embodied by appropriately modifying the design, such as being able to be embodied regardless of the shape, structure, and number of terminal fittings and insulating members. Further, it goes without saying that the present invention can be embodied regardless of the number of electrode terminals in the element.

  In addition, the sensor of the present invention can be embodied by appropriately changing the structure and configuration without departing from the gist of the present invention. In the above description, the oxygen sensor is embodied, but the sensor according to the present invention can also be embodied in other sensors such as a full-range air-fuel ratio sensor and a temperature sensor.

DESCRIPTION OF SYMBOLS 11 Metal fitting body 21 Sensor element 23 The part near the rear end of a sensor element 25 Electrode terminal 51 Terminal metal fitting 61 Lead wire 71,171,271,371 Insulating member 77b, 177b, 277b, 377b Convex part 76b, 176b, 276b of insulating member 376b Recess of insulating member
101 sensor

Claims (5)

A plate-shaped or bar-shaped sensor element that has a detection part on the front end side that is directed to the measurement object and that has electrode terminals on both opposing surfaces near the rear end is arranged through the inside of the cylindrical metal fitting body. The portion close to the rear end of the sensor element protrudes rearward from the rear end of the metal fitting body, and each terminal fitting connected to the tip of the lead wire led out to the outside is pressed against each electrode terminal. A sensor in which an electrical connection is maintained,
The sensor element has a pair of insulating members made of an electrical insulating material arranged so as to sandwich the sensor element from both surface sides via terminal fittings, respectively.
In addition, each insulating member, when both of them sandwich the sensor element from the both surface sides via the terminal fitting, respectively, the insulating member that forms a counterpart facing each other, and the side edges that straddle the sensor element. The convex part formed in the part and the concave part are opposite to each other, and the convex part is provided on one side edge part and the concave part is provided on the other side edge part. In the sensor
When the convex portion is fitted into the concave portion of the other insulating member and the both insulating members sandwich the sensor element from the both surface sides via terminal fittings, the concave portion is the convex portion of the convex portion. The protrusion and the convex portion so that the movement is restricted and the movement of the one insulating member is restricted in any direction along a virtual plane perpendicular to the direction of sandwiching the sensor element with respect to the other insulating member. The sensor is characterized in that the concave portion is formed, and the convex portion and the concave portion are integrally formed by the insulating member itself. The insulating member has a raised portion protruding in the sandwiching direction at any one of the portions near both side edges, and spaced apart from each other.
The sensor according to claim 1, wherein the recess is between the raised portions. The insulating member has a raised portion protruding in the sandwiching direction on either one of the side edge portions.
The sensor according to claim 1, wherein the concave portion is a hole formed in a depressed shape at the top of the raised portion.   The sensor according to claim 1, wherein the pair of insulating members are common parts. The pair of insulating members are arranged so as to sandwich the sensor element from both surface sides via terminal fittings, and both the insulating members are springy in a cylindrical body arranged behind the fitting main body. Is sandwiched by a sandwiching member having
When the cylindrical body is crimped to a reduced diameter, the sandwiching member is deformed, and the terminal fitting is pressed against the electrode terminal of the sensor element to maintain electrical connection. The sensor according to any one of claims 1 to 4, wherein:

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