JP2013101078A - Gas sensor and method for manufacturing gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing costs of a gas sensor, and to provide the gas sensor which facilitates the manufacturing, and a method for manufacturing the gas sensor.SOLUTION: A gas sensor includes: a sensor element 10; a seal member 40 which has a vent hole 41 for introducing the ambient air to a reference gas space to be formed in an outer cylinder 90; and a separator 30 which is disposed on the tip side further than the seal member 40 in the outer cylinder 90. A cylindrical part 34 which projects to the rear end to be inserted into the vent hole 41, and becomes a flow channel for introducing the ambient air to the reference gas space is provided on a surface turning the rear end of the separator 30. A ventilation filter has a mediation part 46 which mediates between an outer side face of the cylindrical part 34, and an inner side face of the ventilation hole 41. The outer cylinder 90 dents inward, and a swage part 91 which pressurizes the seal member 40 inward is provided in an area where the cylindrical part 34 overlaps the mediation part 46 in the outer cylinder 90.

Description

  The present invention relates to a gas sensor suitable for use in detecting the concentration of a specific gas such as oxygen contained in a measurement atmosphere such as exhaust gas discharged from an internal combustion engine, and a method for manufacturing the gas sensor.

  Conventionally, as a gas sensor for detecting the concentration of oxygen contained in exhaust gas, a sensor provided with a gas detection element having oxygen ion conductivity, which is attached to an exhaust pipe of an internal combustion engine of a vehicle is known ( For example, see Patent Document 1).

  Explaining the configuration of the gas sensor described in Patent Document 1 (see FIG. 10), in the gas sensor P1, the gas detection element P2 is fixed in the metal shell P3, and the rear end side of the gas detection element P2 is made of metal. It is covered with an outer cylinder P4.

  In this type of gas sensor P1, a separator P5 is disposed on the rear end side of the gas detection element P2 inside the outer cylinder P4, and the separator P5 is provided by a holding metal fitting P6 disposed between the outer surface and the inner surface of the outer cylinder P4. It is supported.

  Further, the rear end of the outer cylinder P4 is closed by a seal member P7 formed of an elastic member such as rubber. The seal member P7 is formed with an air communication hole P8 that guides the air into the gas detection element P2. Inside the air communication hole P8, a filter member P9 that prevents intrusion of water droplets and the like and a fastener P10 that holds the filter member P9 between the air communication hole P8 are inserted.

Japanese Patent No. 4729427

  In the above-mentioned patent document, the element side subassembly mainly including the gas detection element P2 and the metal shell P3 and the separator side subassembly mainly including the outer cylinder P4, the separator P5, and the seal member P7 are separately assembled. The gas sensor P1 is manufactured by assembling both the subassemblies.

  The separator-side subassembly includes a seal member P7 in which a filter member P9 and a fastener P10 are inserted in the atmosphere communication hole P8 on the surface facing the rear end of the separator P5. It is inserted inside P4. The separator P5 is held in the outer cylinder P4 by a holding metal fitting P6 that is caulked together with the outer cylinder P4, and the seal member P7 is directly held by the caulked outer cylinder P4.

  However, as described above, in the method using the fastener P10 that only fixes the filter member P9 to the seal member P7 or the holder P6 that only holds the separator P5, the number of parts increases and the number of manufacturing steps increases. This increases the manufacturing cost.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a gas sensor and a gas sensor manufacturing method capable of reducing the manufacturing cost of the gas sensor and facilitating the manufacturing. .

In order to achieve the above object, the present invention provides the following means.
A gas sensor of the present invention includes a sensor element that extends along an axial direction and measures a specific gas concentration contained in a measurement atmosphere, a metal shell that holds an end portion of the sensor element in a protruding state, and the metal fitting, A cylindrical outer cylinder disposed on the rear end side of the metal shell, a sealing member disposed in the outer cylinder, and having a vent hole for introducing outside air into a reference gas space formed in the outer cylinder; A sheet-like ventilation filter that covers the ventilation hole of the sealing member, allows passage of the outside air, and prevents passage of moisture, and is disposed on the tip side of the sealing member in the outer cylinder, and is attached to the sensor element. In a gas sensor comprising a connection terminal to be connected and a separator that at least insulates the outer cylinder, the rear end-facing surface of the separator protrudes toward the rear end along the axial direction and is inserted into the vent hole The In addition, a cylindrical portion serving as a flow path for introducing outside air into the reference gas space is provided, and the ventilation filter is provided between the outer side surface of the cylindrical portion and the inner side surface of the vent hole. A caulking portion that includes an intervening portion and that is recessed inwardly and presses the seal member inwardly in a region where the cylindrical portion and the intervening portion of the outer tube overlap. It is characterized by being.

  The gas sensor manufacturing method of the present invention includes a sensor element for measuring a specific gas concentration contained in a measurement atmosphere that extends along the axial direction, and a metal shell that holds the end of the sensor element in a protruding state And a cylindrical outer cylinder disposed on the rear end side of the metal shell, and a sealing member disposed in the outer cylinder and having a vent hole for introducing outside air into a reference gas space formed in the outer cylinder And a sheet-like ventilation filter that covers the ventilation hole of the sealing member, allows passage of the outside air and prevents passage of moisture, and is disposed on the front end side of the sealing member in the outer cylinder, In a method for manufacturing a gas sensor comprising a connection terminal connected to a sensor element and a separator that at least insulates the outer cylinder, the gas sensor protrudes from a rear end-facing surface of the separator toward the rear end along the axial direction. A seal insertion step of inserting a ventilation portion having an interposed portion between an inner surface of the ventilation hole and an outer surface of the cylindrical portion, The separator and the seal member are inserted into the outer cylinder, and the seal member is recessed inwardly in a region where the cylindrical part and the interposition part overlap in the outer cylinder. And a caulking step of pressing inwardly.

  According to the gas sensor and the gas sensor manufacturing method of the present invention, the ventilation filter having the interposed portion interposed between the outer side surface of the cylindrical portion and the inner side surface of the vent hole is sandwiched, and the cylindrical portion and the intermediate portion of the outer cylinder are interposed. By forming the crimped portion in the region where the portion overlaps, the manufacturing cost of the gas sensor can be reduced and the manufacturing can be facilitated. That is, the ventilation filter is pressed and held radially inward by caulking at least part of the intervening part of the ventilation filter between the cylindrical part which is a part of the separator and the ventilation hole formed in the seal member. It is not necessary to use a dedicated part such as a fastener for holding the battery, and the number of parts can be reduced. In addition, by reducing the number of parts, the number of steps for assembling parts when manufacturing the gas sensor can be reduced.

  Furthermore, when the sealing member is pressed inward by the crimping portion, the sealing member is compressed inward, and the cylindrical portion inserted through the vent hole is pressed from the periphery by the sealing member. That is, by providing the crimping portion at a position overlapping the cylindrical portion in the outer cylinder, the seal member and the separator can be fixed to the outer cylinder, and the position and number of the crimping portions can be reduced.

In the said invention, it is preferable that the said cylindrical part is formed in the cylindrical shape.
Thus, by making the shape of a cylindrical part cylindrical, fixing of a separator can be made more reliable and damage to a separator can be controlled. That is, by forming the cylindrical portion in a cylindrical shape, the surface pressure that the outer surface of the cylindrical portion is pressed by the seal member becomes uniform, and the formation of a region having a low surface pressure is suppressed. In other words, the formation of a region where the frictional force that prevents the tubular portion from coming out of the vent hole is reduced is suppressed, and the separator is less likely to come off. On the contrary, it is difficult to form a region where the above-described surface pressure is higher than others, and it is possible to suppress the tubular portion from being damaged by the high surface pressure.

  In the above invention, at least one of a separator projecting portion projecting toward the rear end and a separator concave portion recessed toward the front end is provided on the rear end facing surface of the separator, and faces the rear end facing surface of the seal member. The opposing surface is provided with at least one of a seal recess fitted to the separator protrusion and a seal protrusion fitted to the separator recess, and the seal member is electrically connected to the connection terminal. It is preferable that a conducting wire hole through which the conducting wire is inserted is provided.

  Thus, by performing at least one of the fitting between the separator protrusion and the seal recess and the fitting between the separator recess and the seal protrusion between the separator and the seal member, The posture can be determined. Therefore, the relative position between the conductor hole and the conductor wire of the seal member is also determined, and the relative position between the conductor wire extending from the connection terminal and the conductor hole can be easily matched.

  In the above invention, an engagement convex portion that protrudes in a direction intersecting the axial direction is provided on a side surface in the vicinity of the end portion of the seal protrusion portion, and an inner surface that faces the engagement convex portion in the separator recess portion is provided. It is preferable that an engagement recess is provided in which the engagement protrusion of the seal protrusion fitted into the separator recess is engaged.

  In this way, the seal protrusion is provided with the engagement protrusion, the separator recess is provided with the engagement protrusion, and the engagement protrusion and the engagement recess are engaged with each other. It becomes difficult to leave. In other words, the seal member and the separator are difficult to separate. Therefore, when manufacturing a gas sensor, the seal protrusion part once fitted and the separator recessed part are hard to be separated, and the manufacturing process can be simplified.

  According to the gas sensor and the gas sensor manufacturing method of the present invention, the air filter having the interposition portion is sandwiched between the outer side surface of the cylindrical portion and the inner side surface of the vent hole, and the cylindrical portion and the interposition portion in the outer cylinder By forming the crimped portion in the region where the gas sensors overlap, there are effects that the manufacturing cost of the gas sensor can be reduced and the manufacturing can be facilitated.

It is sectional drawing which shows the structure of the gas sensor which concerns on the 1st Embodiment of this invention. It is a figure explaining the structure of the gas detection element of FIG. It is a perspective view explaining the structure of the separator of FIG. 1, and a sealing member. It is a figure explaining the assembly | attachment method of the gas sensor of FIG. It is a figure explaining the assembly | attachment method of the terminal side subassembly of FIG. It is a perspective view explaining another Example of the sealing member of FIG. It is a perspective view explaining another Example of the sealing member of FIG. It is a perspective view explaining the structure of the separator and sealing member of the gas sensor which concern on the 2nd Embodiment of this invention. It is sectional drawing explaining the structure of the separator of FIG. 8, and a sealing member. It is sectional drawing explaining the structure of the conventional gas sensor.

[First Embodiment]
A gas sensor according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view illustrating the overall configuration of the gas sensor 1 according to the present embodiment.

  In the present embodiment, the gas sensor of the present invention is a sensor that is fastened to an exhaust passage of an internal combustion engine mounted on a vehicle such as a passenger car, for example, and a tip portion of the gas sensor protrudes into the exhaust passage. This will be described by applying to an oxygen sensor that measures the oxygen concentration of the water. In the following description, in the direction along the axis O, the side on which the protector 80 is attached to the metal shell 60 will be referred to as the front end side, and the opposite side will be described as the rear end side.

  The gas sensor 1 of the present embodiment is a sensor including a heater 20 for heating a gas detection element 10 described later, and is activated by heating the gas detection element 10 with the heat of the heater 20, so that the oxygen concentration in the exhaust gas is increased. Is to measure.

  As shown in FIG. 1, the gas sensor 1 includes a gas detection element (sensor element) 10, a heater 20, a separator 30, a seal member 40, a terminal fitting (connection terminal) 50, and a lead wire (conductive wire) 55. Are mainly provided, and a metal shell 60, a protector 80, an outer cylinder 90, and the like that cover the periphery of the metal shell 60 are provided.

  FIG. 2 is a diagram for explaining the configuration of the gas detection element 10 of FIG. 1, and the gas detection element 10 is formed from a solid electrolyte having oxygen ion conductivity. The gas detection element 10 is mainly composed of a cylindrical portion 12 formed in a cylindrical shape extending in the direction of the axis O, and an element main body 11 in which the end portion on the distal end side (the lower end portion in FIG. 2) of the cylindrical portion 12 is closed. It is configured. On the outer periphery of the central portion of the element body 11, a flange portion 14 that protrudes radially outward is provided in the circumferential direction. Note that the inner surface of the gas detection element 10 is in contact with a reference gas space through which the atmosphere is introduced, and the outer surface is in contact with exhaust gas that is a measurement atmosphere flowing through the exhaust passage of the internal combustion engine.

A typical example of the solid electrolyte constituting the element body 11 is ZrO _{2 in} which Y ₂ O ₃ or CaO is dissolved. In addition to this solid electrolyte, a solid electrolyte that is a solid solution of an oxide of an alkaline earth metal or rare earth metal and ZrO ₂ may be used. Further, a solid electrolyte containing HfO _{2 in} a solid solution of an alkaline earth metal or rare earth metal oxide and ZrO ₂ may be used.

  An outer electrode 16, a vertical lead portion 17, and an annular lead portion 18 are formed on the outer peripheral surface of the element body 11. The outer electrode 16 is an electrode in which Pt or a Pt alloy (hereinafter referred to as “Pt or the like”) is formed porous on the tip side of the gas detection element 10. The vertical lead portion 17 is a conductive portion extending in the axial direction from the outer electrode 16 and is formed of Pt or the like. The annular lead portion 18 is a conductive portion that is annularly formed on the rear end side (upper side in FIG. 2) of the gas detection element 10 and is electrically connected to the vertical lead portion 17 and is made of Pt or the like. is there. An inner electrode 19 in which Pt or the like is formed in a porous shape is formed on the inner peripheral surface of the element body 11. In addition, the gas detection element 10 may be formed in a cylindrical shape as described above, or may be formed in a plate shape, and the shape thereof is not limited.

  As shown in FIG. 1, the heater 20 is a long heating unit that is disposed inside the gas detection element 10 and heats the element body 11. A heating portion (not shown) that generates heat when electric power is supplied is provided on the front end side of the heater 20. In this embodiment, the description is applied to an example using a round bar heater. However, the shape of the heater is not limited to the round bar shape, and may be a cylindrical shape or a column shape.

  Further, the heater 20 is disposed obliquely with respect to the axis of the gas detection element 10, and the heat generating portion of the heater 20 is in direct contact with the inner peripheral surface that is the side surface of the cylindrical portion 12 of the element body 11. At the rear end of the heater 20, a pair of electrodes 26 that are electrically connected to the heat generating portion and supply electric power to the heat generating portion are provided. In FIG. 1, only one of the pair of electrodes 26 is shown.

  As shown in FIG. 1, the separator 30 is a member disposed between the gas detection element 10 and the seal member 40, and is a cylindrical member formed of an electrically insulating material such as alumina. The separator 30 is provided with an accommodating portion 31 for accommodating the terminal fitting 50, the electrode 26, and the like. The accommodating portion 31 is a through hole formed so as to penetrate the separator 30 in the direction of the axis O, and allows air to flow between the space on the front end side and the space on the rear end side with respect to the separator 30. It is.

  3 is a perspective view illustrating the configuration of the separator 30 and the seal member 40 in FIG. 1, FIG. 3A shows a state where the separator 30 and the seal member 40 are separated, and FIG. The state which combined the separator 30 and the sealing member 40 is shown.

  Further, as shown in FIGS. 1 and 3A, the separator 30 has a flange portion 32 in which the diameter of the end portion on the seal member 40 side is larger than the diameter of the other portion, and the seal member 40 is opposed to the flange portion 32. A cylindrical tubular portion 34 projecting toward the seal member 40 along the axis O from the center of the rear end-facing surface 33 that is a surface to be separated, and a separator recess 35 recessed toward the gas detection element 10 are provided. It has been.

  The flange portion 32 is provided with a notched surface 36 having a shape obtained by cutting off the cylindrical side surface of the flange portion 32 with a flat surface. By using the notch surface 36 as a reference, when the plurality of flange portions 32 are arranged side by side to be assembled to the gas sensor 1, the flange portions 32 are easily aligned in the same posture. In other words, it is easy to align the phases with the axis O as the center. Thereby, when the flange part 32 mentioned later is assembled | attached, the attitude | position of the flange part 32 can be kept constant and the assembly | attachment of the flange part 32 becomes easy.

  The cylindrical portion 34 is inserted into a vent hole 41 of a seal member 40 described later, and is held between the inner peripheral surface of the vent hole 41 and the outer peripheral surface of the cylindrical portion 34 with the ventilation filter 45 interposed therebetween. To do. The internal space of the cylindrical portion 34 is a flow path that guides the atmosphere to the inside of the gas detection element 10. The cylindrical portion 34 may be formed in a cylindrical shape as described above, or may be formed in another shape, for example, a rectangular tube shape.

  The separator recess 35 is fitted with a seal protrusion 43 of a seal member 40 to be described later, and extends in a groove shape toward the radially outer side with the cylindrical portion 34 as the center. In other words, the relative arrangement phase between the separator 30 and the seal member 40 around the cylindrical portion 34 is determined. In the present embodiment, description will be made by applying to an example in which four separator recesses 35 are arranged at equal intervals (in other words, at 90 ° intervals) in the circumferential direction.

  The seal member 40 is a plug member made of an elastic material such as fluorine rubber, for example, and is a member disposed at the rear end of the gas sensor 1 as shown in FIG. The seal member 40 is a member that is formed in a substantially columnar shape with the axis O direction as the height direction, and closes the rear end of the outer cylinder 90. Specifically, the seal member 40 is fitted into the opening on the rear end side of the outer cylinder 90 and is in contact with the rear end facing surface 33 of the separator 30. The seal member 40 may be in contact with the rear end facing surface 33 of the separator 30 as described above, or may not be in contact with the rear end facing surface 33, and does not limit the presence or absence of contact. Absent.

  A vent hole 41 penetrating in the axis O direction is formed in the center of the seal member 40 in the radial direction, and four lead wire insertion holes (conducting hole) penetrating in the axis O direction radially outward from the vent hole 41 are formed. ) 42 are formed at equal intervals in the circumferential direction, and a seal protrusion 43 that is fitted to the separator recess 35 is formed on the surface of the seal member 40 facing the separator 30.

  By using the seal protrusion 43 as a reference, when the plurality of seal members 40 are arranged side by side to be assembled to the gas sensor 1, the seal members 40 can be easily aligned with the phase around the axis O being aligned. Thereby, when the seal member 40 described later is assembled, the posture of the seal member 40 can be kept constant, and the assembly of the seal member 40 becomes easy.

  The vent hole 41 is a through hole that guides the atmosphere to the inside of the gas detection element 10 through the inside of the outer cylinder 90 that is closed by the seal member 40. A ventilation filter 45 is disposed inside the ventilation hole 41. The ventilation filter 45 is formed in a cylindrical shape with a closed rear end side using, for example, a fluororesin such as PTFE (polytetrafluoroethylene), and is a thin film having a mesh structure in units of micrometers. It is a filter. Therefore, the ventilation filter 45 does not allow the passage of water droplets or the like but allows the passage of the atmosphere. A cylindrical portion of the ventilation filter 45 is an interposition part 46, and the interposition part 46 is interposed between the inner peripheral surface of the vent hole 41 and the outer peripheral surface of the cylindrical part 34.

  The terminal metal fittings 50 are four metal fittings formed from a nickel alloy (for example, Inconel 750, registered trademark of Inconel, UK), each of which is a pair of the outer electrode 16 and inner electrode 19 of the element body 11 and the heater 20. The electrode 26 is electrically connected. The core wire of the lead wire 55 is caulked and connected electrically to each terminal fitting 50. In FIG. 1, three of the four lead wires 55 are illustrated.

  As shown in FIG. 1, the metal shell 60 is a member formed of a stainless alloy (for example, SUS310S of JIS standard), and is a member formed in a substantially cylindrical shape. The metal shell 60 is provided with a step portion 61 that supports the flange portion 14 of the gas detection element 10 so as to protrude in the circumferential direction from the inner circumferential surface toward the radially inner side.

  On the outer peripheral surface on the front end side of the metal shell 60, there are a screw portion 62 for attaching the gas sensor 1 to the exhaust passage of the internal combustion engine, and a hexagonal portion 63 for engaging an attachment tool for screwing the screw portion 62 into the exhaust passage. Are provided over the circumferential direction. An annular gasket 64 is disposed between the screw portion 62 and the hexagonal portion 63. The gasket 64 prevents gas from being released from the gap between the gas sensor 1 and the exhaust passage.

  A front end engaging portion 65 to which a protector 80 described later is engaged is formed on the front end side of the metal shell 60 with respect to the screw portion 62. The tip engaging portion 65 is a portion formed with a smaller diameter on the outer peripheral surface than the screw portion 62. Further, the rear end engaging portion 66 engaged with the outer cylinder 90 and the gas detection element 10 are arranged on the metal shell 60 on the rear end side of the hexagonal portion 63 from the hexagonal portion 63 toward the rear end side. A caulking fixing portion 67 for caulking and fixing is formed.

  Inside the metal shell 60, in order from the step portion 61 toward the rear end side, a metal front end side packing 71, a cylindrical support member 72 made of alumina, a metal rear end side packing 73, and talc powder A filling member 74, an alumina sleeve 75, and an annular ring 76 are disposed. A step portion is formed on the inner peripheral surface of the support member 72, and the flange portion 14 of the element body 11 is supported by the step portion. The rear end side packing 73 is sandwiched between the support member 72 and the flange 14.

  The ring 76 is disposed between the sleeve 75 and the caulking and fixing portion 67, and a force in the distal direction applied by the caulking and fixing portion 67 being deformed radially inward and on the distal end side, This is transmitted to the filling member 74, the rear end side packing 73, the support member 72, and the front end side packing 71. By this pressing force, the filling member 74 is compressed and filled in the direction of the axis O, and airtightly fills the gap between the inner peripheral surface of the metal shell 60 and the outer peripheral surface of the element body 11.

  The protector 80 protects the tip of the gas detection element 10 protruding into the flow path from collision of water droplets or foreign matters contained in the gas flowing in the flow path when the gas sensor 1 is attached to the cylinder head. It is. The protector 80 is a member formed from stainless steel (for example, JIS standard SUS310S), and is a protective member that covers the tip of the gas detection element 10. The protector 80 is a cylindrical member extending in the axial direction, and is formed in a shape with a closed end. The rear end edge of the protector 80 is fixed to the front end engaging portion 65 of the metal shell 60 by welding.

  The protector 80 is formed in a bottomed cylindrical shape that is fixed to the inside of the outer protector 81 and an outer protector 81 in which a peripheral edge portion on the open side that is formed in a bottomed cylindrical shape is fitted to the tip engaging portion 65. An inner protector 82 is provided. In other words, the protector 80 has a double structure composed of the outer protector 81 and the inner protector 82.

  The cylindrical surface of the outer protector 81 and the inner protector 82 is provided with an inlet 83 for introducing gas into the inside. In FIG. 1, only the introduction port 83 of the outer protector 81 is shown, and the introduction port 83 of the inner protector 82 is not shown because of the arrangement. Furthermore, the bottom surface of the outer protector 81 and the inner protector 82 is provided with an outer discharge port 84 and an inner discharge port 85 for discharging water droplets and gas that have entered inside.

  The outer cylinder 90 is a member made of stainless steel (for example, JIS standard SUS304L) different from the metal shell 60, and the rear end engaging portion 66 of the metal shell 60 is inserted into the outer cylinder 90. It is fixed to the metal shell 60 using a method such as caulking or welding. Inside the outer cylinder 90, the rear end of the gas detection element 10 protruding from the rear end of the metal shell 60, the separator 30, and the seal member 40 are disposed.

  A crimping portion 91 is formed at a position overlapping the cylindrical portion 34 of the separator 30 on the side surface of the outer cylinder 90. The caulking portion 91 is a portion obtained by deforming the outer cylinder 90 in a concave shape toward the inside in the radial direction, and is a portion formed in a groove shape that makes a round around the outer cylinder 90 in the circumferential direction. The caulking portion 91 fixes the seal member 40 and the separator 30 to the outer cylinder 90.

Next, a method for manufacturing the gas sensor 1 having the above configuration will be described with reference to FIGS.
As shown in FIG. 4, the gas sensor 1 includes an element-side subassembly 101 including the gas detection element 10 and the metal shell 60, and a terminal-side subassembly 102 including the separator 30, the seal member 40, and the outer cylinder 90. After assembling, both are assembled together.

  Here, an assembly method (manufacturing method) of the terminal-side subassembly 102, which is a feature of the present embodiment, will be described with reference to FIG. In addition, since the assembly method of the element side subassembly 101 is the same as the conventional assembly method, the description is abbreviate | omitted.

  First, the tubular portion 34 of the separator 30 is inserted into the ventilation hole 41 from the front end side (from the lower side of FIG. 5) with the ventilation filter 45 formed in a sheet shape covered with the ventilation hole 41 of the sealing member 40. (Seal insertion process). Thereby, the ventilation filter 45 is formed in a cylindrical shape whose rear end is closed, and the interposition part 46 of the ventilation filter 45 is sandwiched between the inner peripheral surface of the vent hole 41 and the outer peripheral surface of the cylindrical part 34. . An assembly including the seal member 40, the ventilation filter 45, and the separator 30 is referred to as a separator assembly.

  Further, when the tubular portion 34 is inserted into the vent hole 41, the seal protrusion 43 of the seal member 40 is fitted into the separator recess 35 of the separator 30, and the separator 30 and the seal member 40 are relatively relative to each other in the circumferential direction. Position (phase) is determined. The seal member 40 is inserted to a position where the surface facing the rear end facing surface 33 of the separator 30 contacts the rear end facing surface 33. At this time, by using the notch surface 36 and the seal protrusion 43 as a reference, the relative position between the separator 30 and the seal member 40 can be easily determined, and the seal protrusion 43 can be easily fitted into the separator recess 35.

  Thereafter, the lead wire 55 is passed through the opening on the rear end side of the outer cylinder 90, the lead wire insertion hole 42 of the separator assembly, and the accommodating portion 31 in this order, and the end portion of the lead wire 55 is moved from the separator assembly to the front end side. Make it protrude. A terminal fitting 50 is crimped to the end of the protruding lead wire 55 on the distal end side, and the terminal fitting 50 is drawn into the accommodating portion 31 of the separator 30.

  At the same time as or after the terminal fitting 50 is drawn into the housing portion 31, the separator assembly is drawn into the outer cylinder 90 from the front end side (separator insertion step). At this time, the separator 30 is disposed at a position in contact with an outer cylinder stepped portion 92 formed on the rear end side of the outer cylinder 90 where the diameter of the outer cylinder 90 is reduced. Thereby, the terminal side subassembly 102 is completed.

  The completed terminal-side subassembly 102 is inserted into the element-side subassembly 101, and then a crimping portion 91 is formed at a position overlapping the cylindrical portion 34 in the outer cylinder 90, and seals against the outer cylinder 90. The member 40 and the separator 30 are fixed (caulking process). By forming the caulking portion 91, the outer cylinder 90 is recessed toward the seal member 40 (inward), the seal member 40 is pressed inward, and the seal member 40 is fixed to the outer cylinder 90. Is done.

  Further, when the seal member 40 is pressed inward, the outer peripheral surface of the cylindrical portion 34 inserted into the vent hole 41 is pressed by the inner peripheral surface of the vent hole 41 of the seal member 40, and the separator 30 is sealed. It is fixed to the outer cylinder 90 via the member 40.

  The caulking portion 91 may be formed after the terminal-side subassembly 102 is inserted into the element-side subassembly 101 as described above, or before insertion into the element-side subassembly 101. However, the formation timing is not limited.

  According to the gas sensor 1 configured as described above, the ventilation filter 45 having the interposition part 46 interposed between the outer side surface of the cylindrical part 34 and the inner side surface of the ventilation hole 41 is sandwiched, and the cylindrical part in the outer cylinder 90 is sandwiched. By forming the caulking portion 91 in the region where the interposition portion 34 and the interposition portion 46 overlap, the manufacturing cost of the gas sensor 1 can be reduced and the manufacturing can be facilitated.

  That is, at least a part of the interposition part 46 of the ventilation filter 45 is pressed inward in the radial direction between the cylindrical part 34 which is a part of the separator 30 and the ventilation hole 41 formed in the seal member 40. Therefore, it is not necessary to use a dedicated part for holding the ventilation filter 45, and the number of parts such as fasteners can be reduced. Moreover, by reducing the number of parts, the number of processes for assembling parts when manufacturing the gas sensor 1 can also be reduced.

  Further, when the sealing member 40 is pressed inward by the caulking portion 91, the sealing member 40 is compressed inward, and the cylindrical portion 34 inserted through the vent hole 41 is pressed from the periphery by the sealing member 40. . That is, by providing the crimping portion 91 at a position overlapping the cylindrical portion 34 in the outer cylinder 90, the seal member 40 and the separator 30 can be fixed to the outer cylinder 90, and the positions and number of the crimping portions 91 are reduced. be able to.

  Moreover, by making the shape of the cylindrical part 34 cylindrical, the fixing of the separator 30 can be made more reliable, and breakage of the separator 30 can be suppressed. That is, by forming the cylindrical portion 34 in a cylindrical shape, the surface pressure that the outer surface of the cylindrical portion 34 is pressed by the seal member 40 becomes uniform, and the formation of a region where the surface pressure is low is suppressed. In other words, the formation of the region where the frictional force that prevents the tubular portion 34 from coming out of the vent hole 41 is reduced is suppressed, and the separator 30 is less likely to come off. On the contrary, the region where the above-mentioned surface pressure is higher than others is not easily formed, and the tubular portion 34 can be prevented from being damaged by the high surface pressure.

  By fitting the separator recess 35 and the seal protrusion 43 between the separator 30 and the seal member 40, the relative posture between the separator 30 and the seal member 40 can be determined. Therefore, the relative position between the lead wire insertion hole 42 and the lead wire 55 of the seal member 40 is also determined, and the relative position between the lead wire 55 extending from the terminal fitting 50 and the lead wire insertion hole 42 can be easily matched.

  Note that, as in the above-described embodiment, the seal member 40 may be formed in a substantially columnar shape or a cylindrical shape. As shown in FIG. 6, the end portion on the separator 30 side has a large diameter. The sealing member 240 formed in the shape provided with the collar portion 244 may be used.

  In the case of the sealing member 40 not provided with the flange portion 244 as in the present embodiment, the rear end facing surface 33 of the separator 30 directly contacts the outer cylinder step portion 92 of the outer cylinder 90 (see FIG. 1). The relative positions of the separator 30 and the seal member 40 with respect to the outer cylinder 90 can be maintained with high accuracy. On the other hand, as shown in FIG. 6, when the flange portion 244 is provided on the seal member 240, the flange portion 244 comes into contact with the outer cylinder step portion 92, and the seal member 240 is connected to the rear end of the outer cylinder 90. It becomes difficult to come out to the side.

  Further, as in the above-described embodiment, the seal protrusion 40 may be provided on the seal member 40, the separator recess 35 may be provided on the separator 30, and the seal protrusion 43 and the separator recess 35 may be fitted together, or FIG. As shown in a) and FIG. 7B, the separator protrusion 335 may be provided in the separator 330, the seal recess 343 may be provided in the seal member 340, and the separator protrusion 335 and the seal recess 343 may be fitted together.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. The basic configuration of the gas sensor of this embodiment is the same as that of the first embodiment, but the configuration of the separator and the seal member is different from that of the first embodiment. Therefore, in this embodiment, only the configuration of the separator and the seal member will be described with reference to FIGS. 8 and 9, and the description of the other components and the like will be omitted.

  Like the separator 30 of the first embodiment, the separator 430 in the gas sensor 401 of the present embodiment is a member disposed between the gas detection element 10 and the seal member 40, and is a material having electrical insulation, for example, A cylindrical member formed of alumina (see FIG. 1).

  As shown in FIGS. 8A, 8B, and 9, the separator 430 is mainly provided with an accommodating portion 31, a flange portion 32, a cylindrical portion 34, and a separator concave portion 435. ing.

  The separator recess 435 is fitted with a seal protrusion 443 of a seal member 440 described later, and is a recess disposed at equal intervals in the circumferential direction around the cylindrical portion 34 (in other words, at 90 ° intervals). It is.

  On the bottom surface side of the side surface of the separator recess 435, an opening is provided outward in the radial direction with the cylindrical portion 34 as the center, and an engagement protrusion 444 provided in a seal protrusion 443 described later is engaged. An engaging recess 446 is formed.

  The seal member 440 of the present embodiment is a plug member made of an elastic material such as fluoro rubber, for example, like the seal member 40 of the first embodiment, and is a member disposed at the rear end of the gas sensor 401 (FIG. 1).

  The seal member 440 is mainly provided with a vent hole 41, a lead wire insertion hole 42, and a seal protrusion 443. The seal protrusion 443 is a columnar member that protrudes toward the separator 430 from the surface of the seal member 440 that faces the separator 430. On the outer surface of the end of the seal protrusion 443 on the separator 430 side, an engagement protrusion 444 that protrudes outward in the radial direction is provided.

  Thus, the engagement protrusion 444 is provided on the seal protrusion 443, the engagement recess 446 is provided on the separator recess 435, and the engagement protrusion 444 and the engagement recess 446 are engaged with each other, thereby being fitted once. The seal protrusion 443 and the separator recess 435 can be made difficult to separate. In other words, the seal member 440 and the separator 430 are difficult to separate. Therefore, when the gas sensor 401 is manufactured, the seal protrusion 443 and the separator recess 435 that are once fitted together are not easily separated, and the manufacturing process can be simplified.

  DESCRIPTION OF SYMBOLS 1,401 ... Gas sensor, 10 ... Gas detection element (sensor element), 30, 330 ... Separator, 33 ... Rear end facing surface, 34 ... Cylindrical part, 35, 435 ... Separator recess, 40, 240, 340 ... Sealing member , 41 ... vent hole, 42 ... lead wire insertion hole (conductor hole), 43, 443 ... seal projection, 45 ... vent filter, 46 ... interposition part, 50 ... terminal fitting (connection terminal), 55 ... lead wire (conductor wire) ), 60: metal shell, 90: outer cylinder, 91: caulking portion, 335: separator projection, 343: seal recess, 446: engagement recess, 444: engagement projection

Claims (5)

A sensor element that extends along the axial direction and measures the concentration of a specific gas contained in the measurement atmosphere;
A metal shell for holding the sensor element in a state where the end of the sensor element protrudes toward the tip;
A cylindrical outer cylinder disposed on the rear end side of the metal shell,
A seal member disposed in the outer cylinder and having a vent hole for introducing outside air into a reference gas space formed in the outer cylinder;
A sheet-like ventilation filter that covers the ventilation hole of the seal member, allows passage of the outside air, and prevents passage of moisture;
A separator that is disposed on the tip side of the seal member in the outer cylinder, and that at least insulates the connection terminal connected to the sensor element and the outer cylinder;
In the gas sensor with
A surface facing the rear end of the separator is provided with a cylindrical portion that protrudes toward the rear end along the axial direction and is inserted into the vent hole, and that serves as a flow path for introducing outside air into the reference gas space. And
The ventilation filter has an intervening portion interposed between the outer side surface of the cylindrical portion and the inner side surface of the vent hole,
A caulking portion is provided in a region where the tubular portion and the interposition portion of the outer tube overlap each other, and the outer tube is recessed inward and presses the seal member inward. Gas sensor.   The gas sensor according to claim 1, wherein the cylindrical portion is formed in a cylindrical shape. The separator-facing surface of the separator is provided with at least one of a separator protrusion protruding toward the rear end and a separator recess recessed toward the front end.
The opposing surface of the seal member that faces the rear end facing surface is provided with at least one of a seal recess fitted to the separator protrusion and a seal protrusion fitted to the separator recess,
The gas sensor according to claim 1, wherein the seal member is provided with a conductor hole through which a conductor wire electrically connected to the connection terminal is inserted. On the side surface in the vicinity of the end of the seal protrusion, an engagement protrusion that protrudes in a direction intersecting the axial direction is provided,
An engagement recess is provided on the inner surface of the separator recess that faces the engagement protrusion, and the engagement protrusion of the seal protrusion fitted in the separator recess is engaged therewith. The gas sensor according to claim 3. A sensor element that extends along the axial direction and measures the concentration of a specific gas contained in the measurement atmosphere;
A metal shell for holding the sensor element in a state where the end of the sensor element protrudes toward the tip;
A cylindrical outer cylinder disposed on the rear end side of the metal shell,
A seal member disposed in the outer cylinder and having a vent hole for introducing outside air into a reference gas space formed in the outer cylinder;
A sheet-like ventilation filter that covers the ventilation hole of the seal member, allows passage of the outside air, and prevents passage of moisture;
A separator that is disposed on the tip side of the seal member in the outer cylinder, and that at least insulates the connection terminal connected to the sensor element and the outer cylinder;
In the manufacturing method of the gas sensor provided with
A cylindrical portion protruding from the rear end facing surface of the separator to the rear end along the axial direction is inserted into the vent hole from the front end side, and between the inner side surface of the vent hole and the outer side surface of the cylindrical portion. A seal insertion step of sandwiching the ventilation filter having an intervening portion in
A separator insertion step of inserting the separator and the seal member into the outer cylinder from the tip side;
A caulking step of pressing the seal member inward by denting the inside of the region where the cylindrical part and the interposition part overlap in the outer cylinder,
A method for producing a gas sensor, comprising:

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