JP2007304020A - Manufacturing method of sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a sensor for simply and inexpensively incorporating a ventilation filter into a filter holding member while inhibiting damage to the ventilation filter and deterioration in its ventilative property, as to a sensor with gas flowable into and out of the sensor itself through the ventilation filter. <P>SOLUTION: This manufacturing method of an oxygen sensor 1 comprises a deformation/insertion process wherein: a ventilation part 91 of the sheet-shaped ventilation filter 90 closes a filter contact part 72 which is one end of an intra-hole disposition part 71 of a fixation member 70; the ventilation filter 90 and the fixation member 70 are inserted from the ventilation part 91 side into a vent hole 51 of a grommet 50 while a peripheral part 93 positioned on the periphery of the ventilation part 91 deforms the ventilation filter 90 into a pre-insertion form 94 along a peripheral surface 71a of the disposition part 71; and the vent hole 51 is closed with the ventilation filter 90 while the ventilation filter 90 is fixed in the vent hole 51. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a sensor that allows a gas inside and outside thereof to flow through a ventilation filter.

  Conventionally, examples of a sensor that enables a gas inside and outside to flow through a ventilation filter include a gas sensor that detects a concentration of a specific gas component from a mixed gas, and further examples of the gas sensor include an oxygen sensor and an HC sensor. Various types such as NOx sensors and the like are known. For example, in the gas sensor described in Patent Literature 1, a through hole for introducing outside air into the sensor is formed in a form penetrating in the axial direction in a central portion of a seal member provided on one side of the gas sensor. The ventilation filter used for this through-hole is sheet-like and has air permeability and waterproofness. And in this through-hole, it has a sheet-like air permeability and prevention property, has a ventilation filter which closes up the through-hole, and a cylindrical insertion member which fixes this ventilation filter in a through-hole. In this gas sensor, in a state where the ventilation portion of the ventilation filter is covered with the cylindrical insertion member, a part of the peripheral portion of the ventilation filter is partially inserted into the through hole of the sealing member by press-fitting together with the cylindrical insertion member. Is sandwiched between the inner peripheral surface of the tube and the outer peripheral surface of the cylindrical insertion member.

JP 2002-116176 A

  However, in this sensor manufacturing method, the ventilation filter is pushed into the through hole together with the cylindrical insertion member. For this reason, in the middle of insertion, in the vicinity of the opening edge on the insertion side in the through hole of the seal member, the peripheral part of the ventilation filter is bent into approximately 90 degrees and is drawn into the through hole. Since it moves, resistance generated in the ventilation filter is large, and excessive tensile stress may be applied to each part such as between a part already inserted in the through hole and a part not yet inserted in the ventilation filter. As a result, the ventilation filter may be broken or cracked, or the air permeability may be lowered at the portion where the through hole is blocked.

  The present invention has been made in view of such problems, and in a sensor that allows gas to flow between the inside and outside of the sensor through the ventilation filter, the present invention is simple while suppressing damage to the ventilation filter and lowering the air permeability. Another object of the present invention is to provide a sensor manufacturing method capable of assembling a ventilation filter to a filter holding member at low cost.

  The solution is a sensor that enables the inside and outside gas to flow through the ventilation filter, the sheet-like ventilation filter having air permeability and water repellency, and holding holes communicating with the inside and outside of the sensor, respectively. And a fixing member that is disposed in the holding hole of the filter holding member and has an in-hole arrangement portion having a cylindrical shape that is open at both ends, and that fixes the ventilation filter in the holding hole. The ventilation filter is configured to block the holding hole while allowing ventilation through a ventilation portion that is a part of the ventilation filter, and the outer peripheral surface of the in-hole arrangement portion of the fixing member, and the filter holding member. At least a part of the ventilation filter other than the ventilation part is sandwiched between the inner wall surface of the holding hole and the ventilation filter is fixed in the holding hole. In the sheet manufacturing method, in the sheet-like ventilation filter, the ventilation portion closes one end of the fixing member in the hole, and a peripheral portion located around the ventilation portion is in the hole. After the ventilation filter is deformed into the pre-insertion configuration along the outer peripheral surface of the arrangement portion, subsequently, the ventilation filter and the fixing member are connected to the holding hole of the filter holding member from the ventilation portion side. While inserting or deforming the ventilation filter, the deformed portion of the ventilation filter and the fixing member are inserted into the holding hole of the filter holding member from the ventilation portion side, and the ventilation filter is inserted. The sensor manufacturing method includes a deformation insertion step of closing the holding hole with a filter and fixing the ventilation filter in the holding hole.

In the sensor manufacturing method of the present invention, in the deformation insertion step, the ventilation filter is inserted with the ventilation portion closing one end of the in-hole arrangement portion of the fixing member and the peripheral portion along the outer peripheral surface of the in-hole arrangement portion. After the deformation to the front form, subsequently, the ventilation filter and the fixing member are inserted into the holding hole of the filter holding member from the ventilation portion side by a series of operations.
Alternatively, while the ventilation filter is deformed to the pre-insertion configuration, the already deformed portion of the ventilation filter and the fixing member are inserted into the holding hole. The holding hole is closed with the ventilation filter, and the ventilation filter is fixed in the holding hole.
For this reason, when the ventilation filter is inserted into the holding hole together with the in-hole arrangement portion of the fixing member, since the ventilation portion is in a pre-insertion configuration, there is little resistance due to deformation during insertion, and each portion of the ventilation filter is not inserted. Since excessive tensile stress is not applied, it is possible to prevent the ventilation filter from being broken or cracked. In addition, it is possible to prevent a decrease in air permeability in a ventilation portion of the ventilation filter.

In addition, since the ventilation filter is separately formed into a bottomed cylindrical shape and the formed ventilation filter is not inserted, the cost of such molding is not necessary.
In addition, as a ventilation filter, what consists of a flexible sheet-like form and has water repellency and breathability should just be sufficient, for example, the resin sheet (For example, brand name Gore-Tex (for example, brand name Gore-Tex ( Japan Gore-Tex Co., Ltd.) and other paper filters, cotton, fiber filters made of synthetic fibers, and the like.

  Furthermore, in the method for manufacturing the sensor, in the deformation insertion step, the filter holding member has a diameter larger than the holding hole, and gradually decreases from a large diameter end toward a small diameter end. Use a filter deformable tool that makes it possible to configure a tapered insertion deformation path, or a tapered tapered portion that gradually decreases in diameter from the large diameter end toward the small diameter end. A filter deformation tool that can be configured to form a two-part insertion deformation path that is subsequently disposed and has a cylindrical cylindrical portion that has the same diameter as the small end and a diameter that is the same as or larger than the holding hole. In the state where one end of the in-hole arrangement portion of the fixing member is brought into contact with the periphery of the ventilation portion of the sheet-like ventilation filter, the ventilation filter and the fixing are fixed with the ventilation portion at the top. Insert the taper into the hole in the hole. The ventilation filter is inserted into the deformation path from the large-diameter end side toward the small-diameter end side, or inserted into the cylindrical portion through the tapered portion of the two-part insertion deformation path. A method for manufacturing a sensor that is deformed to a pre-insertion configuration is preferable.

In the sensor manufacturing method of the present invention, a filter deformable tool capable of forming a taper insertion deformation path or a two-part insertion deformation path is used in the deformation insertion step.
In the sheet-like ventilation filter, the ventilation filter and the fixing member in-hole arrangement portion with the ventilation portion at the head in a state where one end of the fixing member in-hole arrangement portion is brought into contact with the periphery of the ventilation portion. Is inserted into the taper insertion deformation path from the large diameter end toward the small diameter end, and the ventilation filter is deformed to the pre-insertion configuration. Alternatively, the in-hole arrangement portion of the ventilation filter and the fixing member is inserted into the cylindrical portion through the tapered portion of the two-part insertion deformation path, and the ventilation filter is deformed to the pre-insertion configuration.
As described above, when the ventilation filter is inserted into the deformation path through the taper-shaped tapered insertion deformation path or through the taper portion, the ventilation filter is gradually inserted into the deformation path as the ventilation filter advances in the deformation path. Since the deformation proceeds so as to reduce the diameter, it can be smoothly deformed to the pre-insertion configuration. Moreover, the stress applied to various portions of the ventilation filter can be reduced at the time of deformation to the pre-insertion configuration.

The tapered portion of the taper insertion deformation path or the two-part insertion deformation path has a larger diameter than the holding hole of the filter holding member, and gradually decreases in diameter from the large diameter end toward the small diameter end. Any form having a tapered shape may be used. Furthermore, as the taper shape, it is particularly preferable to form a tapered surface of a truncated cone that decreases in diameter at a constant rate from the large diameter end toward the small diameter end, or an R-surface tapered surface that protrudes toward the deformation path. This is because by moving the ventilation filter along this surface, it can be deformed more smoothly.
Further, examples of the filter deformation tool include a filter deformation tool that can be configured by combining a plurality of movable members in addition to a through hole that forms a taper insertion deformation path or a two-part insertion deformation path.

  Furthermore, it is a manufacturing method of the sensor of Claim 2, Comprising: The surface which makes the said taper insertion deformation path or the said 2 part insertion deformation path among the said filter deformation tools is the said holding hole of the said filter holding member. It is preferable that the ventilation filter is more slippery than the inner wall surface of the sensor.

In the sensor manufacturing method of the present invention, the surface of the taper insertion deformation path or the surface of the two-part insertion deformation path is a filter in which the ventilation filter is made more slippery than the inner wall surface of the holding hole of the filter holding member. Use a deforming tool.
Thus, when the ventilation filter is deformed to the pre-insertion configuration, the frictional force generated between the ventilation filter and the surface of the filter deformation tool that forms the tapered insertion deformation path or the surface that forms the two-part insertion deformation path. Can be made smaller. For this reason, when the ventilation filter is deformed to the pre-insertion configuration, it is possible to further reduce the stress generated in various parts of the ventilation filter.
In addition, as a filter deformation tool in which the surface that forms the taper insertion deformation path and the surface that forms the two-part insertion deformation path is made slippery, the surface roughness of the surface that forms these insertion deformation paths is maintained, for example. Examples thereof include a filter deforming tool finished to be smaller than the surface roughness of the inner wall surface of the hole, and a filter deforming tool in which a lubricant that lowers the friction coefficient is attached to the surface forming the insertion deformation path.

  Furthermore, it is a manufacturing method of the sensor according to any one of the above, wherein the ventilation filter is a manufacturing method of a sensor made of a resin sheet having a porous fiber structure.

  The ventilation filter used in the method for producing a sensor of the present invention is a resin sheet having a porous fiber structure. As described above, in the manufacturing method of the present invention, the stress generated in various portions of the ventilation filter is reduced. Therefore, even if the ventilation filter has a porous fiber structure, the ventilation filter is broken or cracked. It is possible to appropriately avoid the occurrence of the above and the deterioration of the air permeability in the ventilation portion, and fix to the holding hole.

  Furthermore, in the sensor manufacturing method according to any one of the above, the sensor is a gas sensor that detects at least one of a ratio, a concentration, and a concentration change with respect to a specific gas component in a gas to be measured. Thus, it is preferable to use a method for manufacturing a sensor which is a gas sensor that takes outside air into the gas sensor through the ventilation filter and uses it as a reference gas.

The sensor in the sensor manufacturing method of the present invention is a gas sensor that takes outside air into the gas sensor through a ventilation filter and uses it as a reference gas.
In the present invention, when fixing the ventilation filter in the holding hole of the filter holding member, it is possible to suppress the generation of tears and cracks that occur in the ventilation filter and the decrease in air permeability in the ventilation part. Thus, outside air can be appropriately taken into the gas sensor.
Therefore, the gas sensor manufactured thereby can accurately detect at least one of the ratio, concentration, and concentration change of the specific gas component in the gas to be measured.

(Embodiment)
Hereinafter, an embodiment of a method for manufacturing an oxygen sensor 1 embodying the present invention will be described with reference to FIGS. In the present embodiment, a gas sensor, more specifically, a method for manufacturing the oxygen sensor 1 among the sensors that allow gas to flow inside and outside through the ventilation filter will be described in detail. The oxygen sensor 1 according to this embodiment is a sensor that measures the oxygen concentration in the exhaust gas of a vehicle. FIG. 1 is a cross-sectional view showing the form and structure of an oxygen sensor 1 according to this embodiment. FIG. 2 is an enlarged cross-sectional view showing the seal unit 5 before being inserted into the proximal end opening 422 of the outer cylinder 42 in the oxygen sensor 1 of FIG.
Hereinafter, in the description of the oxygen sensor 1 and each component of the present embodiment, in the direction (axial direction) along the axis AX in FIG. 1, the upper side in FIG. 1 is the base end side, and the lower side in FIG. And

As shown in FIG. 1, the oxygen sensor 1 includes an oxygen detection element 2 that extends along an axis AX and is formed in a bottomed cylindrical shape with a distal end portion 21 closed, and an axial shape that is disposed in the oxygen detection element 2. The ceramic heater 3, the case 4 for housing the oxygen detection element 2, and the like.
The oxygen detection element 2 is made of a solid electrolyte body having oxygen ion conductivity and containing ZrO 2 as a main component. An outer electrode (not shown) is formed on the outer peripheral surface 2 a of the oxygen detection element 2 at the distal end portion 21 of the oxygen detection element 2. The outer electrode is a porous film made of Pt or a Pt alloy, and is electrically connected to the lead wire 111 through the external electrode terminal member 11.
On the other hand, an inner electrode (not shown) is also formed on the inner peripheral surface 2 b of the oxygen detection element 2 at the distal end portion 21 of the oxygen detection element 2. This inner electrode is also a porous coating made of Pt or a Pt alloy, and is electrically connected to the lead wire 121 via the internal electrode terminal member 12.

  The case 4 of the oxygen sensor 1 fixes the oxygen sensor 1 to an attachment portion such as an exhaust pipe, and holds the oxygen detection element 2 while projecting the distal end portion 21 inside the exhaust pipe or the like. A metal shell 41 is included. Further, an outer cylinder 42 is provided which extends to the base end side of the metal shell 41 and introduces the atmosphere into the oxygen detection element 2 from the base end side of the oxygen sensor 1.

The metal shell 41 is made of metal and is formed in a cylindrical shape. A protector 43 is provided on the front end side of the metal shell 41. The protector 43 is made of metal and has a bottomed cylindrical shape, and has a plurality of gas inlets for bringing the exhaust gas in the exhaust pipe into contact with the oxygen detection element 2.
On the other hand, a caulking portion 411 having a distal end edge extending radially inward is formed on the base end side of the metal shell 41. Further, a taper-shaped inner peripheral receiving portion 412 that is reduced in diameter toward the tip end side is provided on the inner peripheral surface of the metal shell 41 so as to protrude radially inward.

The oxygen detection element 2 is arranged in a state in which the flange portion 22 is supported by the inner peripheral receiving portion 412 in the metal shell 41 via the ceramic holder 6. Further, the ceramic holder 7, the ceramic powder 8, and the ring 9 are disposed between the metal shell 41 and the oxygen detection element 2, and a caulking portion 411 positioned at the base end of the metal shell 41 is interposed through the ring 9. The ceramic holder 7 and the ceramic powder 8 are pressed. Thereby, the oxygen detection element 2 is fixed in the metal shell 41.
Furthermore, the front end 421 of the outer cylinder 42 is fitted and welded to the metal shell 41 from the base end side. On the other hand, in the base end opening 422 that opens to the base end side of the outer cylinder 42, the base end opening 422 is closed to form a reference gas space GS inside the case 4 and the oxygen detection element 2. A cylindrical seal unit 5 is inserted. However, outside air (oxygen) is introduced into the reference gas space GS through the ventilation path 75 penetrating through the center of the seal unit 5. As will be described later, in the seal unit 5, a plurality of insertion holes 55 and 56 are formed in the grommet 50, and lead wires 111 and 121 that are electrically connected to the oxygen detection element 2 are formed in the insertion holes. Lead wires 13 inserted through 55 and 56 and electrically connected to the ceramic heater 3 are inserted through insertion holes (not shown).

  Next, the detailed structure of the seal unit 5 in a state before being assembled to the oxygen sensor 1 will be described with reference to FIGS. 3 is a cross-sectional view showing a grommet 50 used for the seal unit 5 in the oxygen sensor 1 of FIG. FIG. 4 is a cross-sectional view showing the fixing member 70 used in the seal unit 5. FIG. 5 is a perspective view of the ventilation filter 90 used in the seal unit 5 and showing a state before an insertion form to be described later.

  The seal unit 5 includes a columnar grommet 50 made of fluoro rubber, a fixing member 70 having an in-hole arrangement portion 71 that can be fitted into a vent hole 51 that penetrates the center of the grommet 50 in the axial direction, and the grommet 50. The sheet-like ventilation filter 90 is sandwiched and fixed between the inner wall surface 53a of the ventilation hole 51 and the outer circumferential surface 71a of the fixing member 70 (see FIG. 2).

  As shown in FIG. 3, the vent 51 of the grommet 50 includes a filter closing side portion 52 positioned on the outer surface 50a side, a filter insertion side portion 54 positioned on the sensor inner surface 50b side, and the filter closing side portion 52 and the filter. It consists of a cylindrical filter fixing part 53 located in the middle of the insertion side part 54. Of these, the filter closing side portion 52 is recessed in a disk shape having a larger diameter than the filter fixing portion 53. In addition, grooves that are radially recessed in the outer surface 50 a are formed so as to reach the inner peripheral surface of the filter closing side portion 52. The filter insertion side portion 54 has a taper shape whose diameter increases from the filter fixing portion 53 toward the sensor inner side surface 50b.

  Also, the grommet 50 has a plurality of lead wire insertion holes 55 and 56 (two shown in FIGS. 1 and 2) penetrating in the axial direction, located radially outside the vent hole 51 and centering on the axis AX. Are formed at equal intervals on virtual circles having a predetermined diameter. As described above, the lead wires 111 and 121 are inserted into the lead wire insertion holes 55 and 56. The grommet 50 corresponds to the filter holding member of the present invention.

  The fixing member 70 is made of stainless steel, and as shown in FIG. 4, is formed in an outer shape and a substantially top hat shape with both ends opened. In the oxygen sensor 1, the fixing member 70 is disposed in the hole at a position intermediate between the flange 73 disposed on the distal end side, the folded portion 74 disposed on the proximal end side, and the flange 73 and the folded portion 74. Part 71. The in-hole arrangement portion 71 of the fixing member 70 is formed in a cylindrical shape that can be fitted to the filter fixing portion 53 of the ventilation hole 51 of the grommet 50.

  Specifically, a flange 73 that extends radially outward from the in-hole arrangement portion 71 is provided around the tip of the in-hole arrangement portion 71. On the other hand, a folded portion 74 that is folded in an R shape toward the inside of the cylinder is formed at the proximal end portion of the in-hole arrangement portion 71. In the seal unit 5, the filter abutting portion 72 located closest to the proximal end in the in-hole arrangement portion 71 abuts on a ventilation peripheral edge 92 of the ventilation filter 90 described below. The filter contact portion 72 corresponds to one end of the in-hole arrangement portion of the present invention.

The ventilation filter 90 is a flexible sheet-like resin filter. As shown in FIG. 5, the form before being assembled to the seal unit 5 (hereinafter referred to as “form before assembling”) is a circular shape. Yes. This ventilation filter 90 has a porous fiber structure obtained by stretching a green body of polytetrafluoroethylene (PTFE) in one direction at a heating temperature lower than the melting point of PTFE. This is configured as a ventilation filter that prevents permeation of a liquid mainly composed of and allows permeation of gas such as air. More specifically, an air filter having a trade name of Gore-Tex (manufactured by Japan Gore-Tex Co., Ltd.) is used.
In addition to such breathability and water repellency, as a breathable filter having oil repellency, a breathing filter of a trade name Oleovent filter (manufactured by Japan Gore-Tex Co., Ltd.) or the like can also be used. When this ventilation filter is used for the oxygen sensor 1, when the outside air is introduced into the oxygen sensor 1, the oil adhering to the ventilation filter is vaporized and the risk of entering the oxygen sensor 1 may be further reduced. it can.

  Of the ventilation filter 90, an annular ventilation peripheral edge 92 located substantially in the center serves as a portion that abuts the filter contact portion 72 of the fixing member 70 when assembled to the seal unit 5. Further, a portion surrounded by the ventilation peripheral edge portion 92 becomes a ventilation portion 91 located on the proximal end side of the in-hole arrangement portion 71. The ventilation portion 91 is a portion that can introduce outside air into the oxygen sensor 1 through the ventilation path 75 of the fixing member 70 while closing the proximal end of the in-hole arrangement portion 71 of the fixing member 70. In addition, the peripheral portion 93 positioned on the radially outer side of the ventilation peripheral edge portion 92 is sandwiched between the inner wall surface 53 a of the filter fixing portion 53 and the outer peripheral surface 71 a of the in-hole arrangement portion 71 of the fixing member 70 in the grommet 50. The ventilation filter 90 is fixed to the grommet 50 together with the fixing member 70.

  As described above, in the sealing unit 5, the ventilation filter 90 has the ventilation portion 91 positioned on the filter closing side portion 52 of the grommet 50 and the peripheral portion 93 fixed to the inner wall surface 53 a of the ventilation hole 51 of the grommet 50 and the fixing member. It is fixed in the vent hole 51 of the grommet 50 together with the fixing member 70 while being sandwiched between the outer peripheral surface 71 a of the in-hole arrangement portion 71 of 70. The fixing member 70 is positioned in the axial direction by engaging the flange 73 and the filter insertion side portion 54 of the grommet 50.

Next, a method for manufacturing the oxygen sensor 1 according to this embodiment will be described. However, in this oxygen sensor 1, a known method may be used except for the assembly of the ventilation filter 90 and the fixing member 70 into the grommet 50, and thus the seal unit 5 is inserted into the proximal end opening 422 of the outer cylinder 42. The assembly of the seal unit 5 in a state before the operation will be mainly described, and the other will be briefly described.
As shown in FIGS. 6 and 7, the seal unit 5 uses the insertion device 100 described below to insert the ventilation filter 90 and the in-hole arrangement portion 71 of the fixing member 70 into the ventilation hole 51 of the grommet 50. To form. Therefore, first, the insertion device 100 will be briefly described, and then assembly of the seal unit 5 using these will be described.
FIG. 6 is an explanatory cross-sectional view showing a state before the ventilation filter 90 in the pre-assembly configuration is transformed into the pre-insertion configuration in the assembly process of the seal unit 5. FIG. 7 is an explanatory cross-sectional view showing a state in which the ventilation filter 90 is inserted into the grommet 50 while being deformed into a pre-insertion configuration. Hereinafter, in the description of the assembly process of the seal unit 5, among the directions along the axis P (axis direction) in FIGS. 6 and 7, the upper direction in FIGS. 6 and 7 is the upper axis, and FIGS. The lower part of the axis is the lower part of the axis.

  The insertion device 100 includes a lifting head 250, a pedestal 230, and a filter deformation tool 200. Among these, the elevating head 250 is movable in the axial direction (vertical direction in FIG. 6), and a rod-shaped rod portion 251 having a diameter that can be inserted into the inner periphery of the in-hole arrangement portion 71 of the fixing member 70 is disposed below the axial line. I have. The rod portion 251 can temporarily hold the fixing member 70 in a state where the rod portion 251 is inserted into the in-hole arrangement portion 71, and is fixed after the in-hole arrangement portion 71 is inserted into the vent hole 51 of the grommet 50. The member 70 can be released. The insertion device 100 lowers the elevating head 250 holding the fixing member 70 on the rod portion 251 to generate a pressing force sufficient to be inserted into the ventilation hole 51 of the grommet 50 together with the ventilation filter 90 and the fixing member 70. It is configured as follows.

  The pedestal 230 includes a grommet holding base 231 and a support 234. The grommet holding base 231 is made of metal, and, as shown in FIGS. 6 and 7, a housing hole 232 located at the center, above the axis, and a support housing located below the axis that communicates with the housing hole 232. Hole 233. Among these, the accommodation hole 232 is a cylindrical recess that can accommodate the grommet 50, and has an inner peripheral surface 232 a that contacts the outer peripheral surface 50 c of the grommet 50. On the other hand, the support tool accommodation hole 233 is a cylindrical hole having a diameter smaller than that of the accommodation hole 232, and a columnar support tool 234 is fitted therein.

The support tool 234 fitted and inserted into the support tool accommodation hole 233 is made of metal, and as shown in FIGS. 6 and 7, an approximately cylindrical relief hole 235 is provided in the center of the support surface 234a at the upper end thereof. It is a cylindrical shape. The escape hole 235 is slightly larger in diameter than the vent hole 51 of the grommet 50, and the ring-shaped support surface 234 a is located in the accommodation hole 232 of the grommet holding base 231 and supports the grommet 50.
The escape hole 235 is provided to prevent the ventilation filter 90 and the fixing member 70 from colliding with the support 234 when the rod portion 251 of the elevating head 250 is inserted into the ventilation hole 51 of the grommet 50. .

  Further, the filter deforming tool 200 is made of metal, and as shown in FIGS. 6 and 7, the filter deforming tool 200 is composed of two members, partial deforming tools 201 and 211, each having a substantially semi-cylindrical recess formed in each side portion. . The partial deformation tools 201 and 211 are used such that both are brought into contact with each other and a through hole (filter deformation hole 202) is formed between the side surfaces of both. The partial deformation tools 201 and 211 are a pair of members formed symmetrically (left and right in FIGS. 6 and 7). The partial deforming tools 201 and 211 are closest to each other when the two are brought into contact with each other, and are deformed portions 201F and 211F whose thickness (dimension in the axial direction) is reduced, and from the axis P more than the deformed portions 201F and 211F. Sliding portions 201S and 211S located at a distance equal to or greater than the radius of the grommet 50.

  The partial deforming tools 201 and 211 are arranged in a state where the sliding portion lower end surfaces 201Sa and 211Sa of the sliding portions 201S and 211S are in contact with the sliding surface 231a above the axis of the grommet holding base 231. The partial deforming tools 201 and 211 are moved in a direction in which the deforming portions 201F and 211F are close to each other and away from each other about the axis P by sliding the sliding portions 201S and 211S on the grommet holding base 231 of the base 230. It can be moved in both directions (left and right in FIGS. 6 and 7).

As described above, in the filter deforming tool 200, when the partial deforming tool 201 and the partial deforming tool 211 are brought into abutment with each other, they are disposed between the facing deforming portion 201F and the deforming portion 211F in the direction of the axis P. A filter deformation hole 202 penetrating through is formed.
In the present embodiment, the filter deformation hole 202 is located on the upper side of the axis, and is a tapered taper that gradually decreases in diameter from the large diameter end 203L above the axis toward the small diameter end 203N below the axis. It consists of a part 203 and a cylindrical part 204 which is located below the axis line following the tapered part 203. Among these, the taper part 203 is comprised by the taper surfaces 203a and 203b formed in the deformation | transformation parts 201F and 211F of the partial deformation tools 201 and 211, respectively. Moreover, the cylindrical part 204 is comprised by the semi-cylindrical semi-cylindrical surfaces 204a and 204b formed in the deformation | transformation parts 201F and 211F of the partial deformation tools 201 and 211, respectively. The inside diameter of the small diameter end 203N of the tapered portion 203 and the inside diameter of the cylindrical portion 204 are the same, and both are larger than the inside diameter of the filter fixing portion 53 in the vent hole 51 of the grommet 50.
In this embodiment, the filter deformation hole 202 corresponds to the two-part insertion deformation path of the present invention, the tapered portion 203 corresponds to the tapered portion, and the cylindrical portion 204 corresponds to the cylindrical portion.

Of the deformation portions 201F and 211F forming the filter deformation hole 202, the tapered surfaces 203a and 203b and the semi-cylindrical surfaces 204a and 204b are in a state in which the ventilation filter 90 is more slippery than the inner wall surface 53a of the grommet 50.
Specifically, in this embodiment, the surface roughness of the tapered surfaces 203a and 203b and the semi-cylindrical surfaces 204a and 204b is made smaller than the surface roughness of the inner wall surface 53a. For example, while the surface roughness Ra of the inner wall surface 53a is Ra = 0.82 (μm), the average value of the surface roughness Ra on the tapered surfaces 203a, 203b and the semi-cylindrical surfaces 204a, 204b is Ra = 0.22 (μm).
In addition, in order to make the ventilation filter slip easily on the surface that forms the two-part insertion deformation path or the taper insertion deformation path described later, in addition to reducing the surface roughness of the insertion deformation path, a lubricant that reduces the friction coefficient is attached to this surface. The technique to make is mentioned.

In addition, in the filter deformation tool 200, a filter placement for placing the ventilation filter 90 (see FIG. 5) in the form before assembly in a state in which the deformation portions 201F and 211F are in contact with each other. A recess 205 is provided. The mounting surface 201Fa of the deforming part 201F and the mounting surface 211Fa of the deforming part 211F forming the filter mounting recessed part 205 are subjected to filter deformation at the venting part 91 and in the vicinity thereof when the pre-assembled ventilation filter 90 is placed. Of the holes 202, the large diameter end 203L is closed.
On the other hand, of the deformed portions 201F and 211F, the lower end surfaces 201Fb and 211Fb located below the axis are located above the sliding portion lower end surfaces 201Sa and 211Sa. When the grommet 50 is disposed in the storage hole 232 of the pedestal 230, the gap between the sensor inner side surface 50 b of the grommet 50 and the lower end surfaces 201 Fb and 211 Fb of the deforming portions 201 F and 211 F is set in the in-hole arrangement portion 71 of the fixing member 70. It is made to become shorter than the axial direction length.

Next, the assembly process of the seal unit 5 will be described.
Initially, the partial deformation tools 201 and 211 are located at positions spaced from each other and the axis P, and the lifting head 250 is positioned above the pedestal 230 and the partial deformation tools 201 and 211 in the axial direction. The grommet 50 is accommodated in the grommet holding base 231 so that the outer side surface 50a of the grommet 50 faces the lower side of the axis and the inner side surface 50b of the sensor is positioned higher than the sliding surface 231a of the grommet holding base 231. Insert into 232. The grommet 50 inserted into the accommodation hole 232 is in a state in which the outer surface 50 a is supported by the support surface 234 a of the support tool 234. Next, the partial deforming tools 201 and 211 are moved in a direction approaching each other and abutted against each other. Further, the ventilation filter 90 in the form before assembly is placed in the filter placement recess 205 of the filter deformation tool 200. As a result, the ventilation portion 91 of the ventilation filter 90 closes the upper axis of the filter deformation hole 202. On the other hand, the rod portion 251 of the elevating head 250 is covered with the in-hole arrangement portion 71 of the fixing member 70, and the fixing member 70 is held by the rod portion 251.

  Next, the elevating head 250 is moved downward along the axis, and the fixing member 70 held by the rod portion 251 is moved downward along the axis. Then, the filter contact portion 72 of the in-hole arrangement portion 71 comes into contact with the ventilation peripheral edge portion 92 of the ventilation filter 90 arranged in the filter mounting recess 205, and the ventilation portion 91 is arranged in the hole arrangement portion of the fixing member 70. The filter contact part 72 which is one end of 71 is obstruct | occluded.

When the elevating head 250 is further moved downward along the axis line, the vent portion 90 of the vent filter 90 starts at the head, and the in-hole arrangement portion 71 of the vent filter 90 and the fixing member 70 enters the filter deformation hole 202 from the tapered portion 203 side. Inserted. Then, the peripheral portion 93 of the ventilation filter 90 moves along the tapered surfaces 203 a and 203 b forming the tapered portion 203 and is further drawn into the cylindrical portion 204. Thus, the drawn-in peripheral portion 93 is sandwiched between the outer peripheral surface 71a of the in-hole arrangement portion 71 of the fixing member 70 and the semicylindrical surfaces 204a and 204b of the cylindrical portion 204, and the outer periphery of the in-hole arrangement portion 71 The surface 71a is deformed.
In this way, when the pre-assembly form (sheet-like) ventilation filter 90 is inserted into the filter deformation holes 202 of the partial deformation tools 201 and 211, the ventilation filter 90 is disposed in the holes of the ventilation portion 91 and the fixing member 70. One end of the part 71 is closed, and the peripheral part 93 is deformed into a form along the outer peripheral surface 71a of the in-hole arrangement part 71, that is, a pre-insertion form 94 (see FIG. 7).

Moreover, as described above, when the ventilation filter 90 in the pre-assembly form is deformed to the pre-insertion form 94, the diameter of the ventilation filter 90 gradually decreases as it advances from the tapered portion 203 into the cylindrical portion 204. Since the deformation proceeds, it can be smoothly deformed to the pre-insertion configuration 94.
Therefore, the stress applied to various portions of the ventilation filter 90 can be reduced at the time when the pre-insertion configuration 94 is deformed.

  Further, as shown in FIG. 7, while the ventilation filter 90 is deformed to the pre-insertion configuration, a part of the ventilation part 91 and the peripheral part 93 of the ventilation filter 90 and a part of the in-hole arrangement part 71 of the fixing member 70 are changed. The grommet 50 is inserted into the vent hole 51. In the present embodiment, when the ventilation portion 91 of the ventilation filter 90 and the in-hole arrangement portion 71 of the fixing member 70 begin to be inserted into the ventilation hole 51 of the grommet 50, the partial deformation tools 201 and 211 are moved away from the axis P, respectively. It is moved in the direction (left and right direction in FIG. 7). The moving amount of the partial deforming tools 201 and 211 is sufficient to allow the lifting head 250, the fixing member 70, and the ventilation filter 90 to be inserted between the partial deforming tools 201 and 211. After the partial deformation tools 201 and 211 are moved, the elevating head 250 is lowered until the collar portion 73 of the fixing member 70 engages with the filter insertion side portion 54 of the grommet 50, together with the in-hole arrangement portion 71 of the fixing member 70. The ventilation filter 90 having the pre-insertion configuration 94 is inserted into the ventilation hole 51 of the grommet 50. Accordingly, the ventilation portion 91 is disposed on the filter closing side portion 52.

Thereafter, the lifting head 250 is reversed and moved upward in the axial direction, and the rod portion 251 is pulled out from the vent hole 51 while the fixing member 70 remains. Thus, the assembly of the seal unit 5 is completed (see FIG. 2).
In the seal unit 5 that has been assembled, the peripheral portion 93 of the ventilation filter 90 is sandwiched between the inner wall surface 53 a of the grommet 50 and the outer peripheral surface 71 a of the in-hole arrangement portion 71 of the fixing member 70. The ventilation filter 90 and the fixing member 70 are fixed.

  According to the assembly of the seal unit 5 described above, since the ventilation filter 90 is in the pre-insertion configuration 94 before being inserted into the ventilation hole 51, the ventilation filter 90 is deformed so much when being inserted into the ventilation hole 51. Since there is no need, resistance due to insertion is small, and excessive tensile stress is not applied to each part of the ventilation filter 90. For this reason, the tearing and crack generation in the ventilation filter 90 can be prevented. Further, it is possible to prevent a decrease in air permeability in the ventilation portion 91 and the like in the ventilation filter 90.

  Further, when the ventilation filter 90 is assembled into the ventilation hole 51 of the grommet 50, the ventilation filter 90 of the pre-assembly configuration is transformed into the pre-insertion configuration 94 immediately before the ventilation filter 90 is inserted into the ventilation hole 51 of the grommet 50. The For this reason, since the ventilation filter 90 in the form before assembly is separately separately formed into a bottomed cylindrical shape and the formed ventilation filter is not inserted, the cost of such molding is also unnecessary.

In particular, in the present embodiment, the surface roughness of the tapered surfaces 203a and 203b and the semi-cylindrical surfaces 204a and 204b forming the filter deformation hole 202 in the partial deformation tools 201 and 211 is set to the surface roughness of the inner wall surface 53a of the grommet 50. Smaller than
As a result, when the pre-assembly vent filter 90 is deformed into the pre-insertion configuration 94, friction occurs between the peripheral portion 93 of the vent filter 90 and the tapered surfaces 203a and 203b and the semi-cylindrical surfaces 204a and 204b. The power can be made smaller. For this reason, the stress which arises in each place of the ventilation filter 90 can further be reduced.

Subsequently, production of the oxygen sensor 1 will be described.
Separately, the remaining part of the oxygen sensor 1 excluding the seal unit 5 is assembled by a known method. Further, the lead wires 111, 121, and 13 are inserted into the lead wire insertion holes 55 and 56 of the grommet 50, respectively. Then, the seal unit 5 is inserted into the proximal end opening 422 of the outer cylinder 42, and the seal unit 5 is caulked inward in the radial direction together with the outer cylinder 42 to fix the seal unit 5 to the outer cylinder 42. The oxygen sensor 1 is completed (see FIG. 1).

  Thus, when the ventilation filter 90 is fixed in the ventilation hole 51 of the grommet 50, the ventilation filter 90 can be prevented from being broken or cracked, and the air permeability in the ventilation part 91 can be prevented from being lowered. Therefore, the oxygen sensor 1 according to the present embodiment. In actual use, outside air can be appropriately taken into the reference gas space GS of the oxygen sensor 1 through the ventilation portion 91.

Here, the principle of measuring the oxygen concentration in the exhaust gas using the oxygen sensor 1 will be briefly described.
In the oxygen detection element 2, an exhaust gas as a measurement gas is brought into contact with the outer peripheral surface 2a, and the air as a reference gas is brought into contact with the inner peripheral surface 2b. Then, in the oxygen detection element 2 made of a solid electrolyte body having oxygen ion conductivity, an oxygen concentration cell electromotive force is generated according to the difference in oxygen concentration between the inner and outer peripheral surfaces 2a and 2b.
In the oxygen detection element 2, the electric potential of the outer peripheral surface 2 a is taken out through an external electrode (not shown), the external electrode terminal member 11, and the lead wire 111 formed on the outer peripheral surface 2 a. The potential of the inner peripheral surface 2b is taken out through an internal electrode (not shown) formed on the inner peripheral surface 2b, the internal electrode terminal member 12, and the lead wire 121.
Thus, the oxygen sensor 1 according to the present embodiment can detect the oxygen concentration of the exhaust gas by measuring the voltage between the lead wires 111 and 121. In the oxygen sensor 1 of the present embodiment, the oxygen detection element 2 is heated by the ceramic heater 3 so that the oxygen detection element 2 is activated early.

(Modification 1)
Next, an example in which the insertion device 300 having the filter deformation tool 400 is used instead of the filter deformation tool 200 according to the modification of the above embodiment will be described with reference to FIG.
The insertion device 300 used in the first modification is different from the insertion device 100 used in the above-described embodiment in the shape of the deformation tool 200 in the portion of the filter deformation hole of the filter deformation device 400, but in the other portions. This is the same as the insertion device 100. Therefore, description of the same part will be omitted or simplified, and different parts will be mainly described.

  The partial deforming tools 401 and 411 constituting the filter deforming tool 400 are arranged in a state in which the sliding portion lower end surfaces 401Sa and 411Sa of the sliding portions 401S and 411S are in contact with the sliding surface 231a above the axis of the grommet holding base 231. Is done. When the sliding portions 401S and 411S slide on the grommet holding base 231 of the pedestal 230, the partial deforming tools 401 and 411 move toward and away from the deforming portions 401F and 411F around the axis P. It can move in both directions (left and right in FIG. 8).

In the filter deforming tool 400, when the partial deforming tool 401 and the partial deforming tool 411 are brought into abutment with each other, the filter deforming between the facing deforming portion 401F and the deforming portion 411F and penetrating them in the axis P direction. A hole 402 is formed.
This filter deformation hole 402 has a larger diameter than the vent hole 51 of the grommet 50, and has a taper-like taper insertion that gradually decreases in diameter from the large-diameter end 402L above the axis toward the small-diameter end 402N below the axis. A deformation path is formed. The filter deformation hole 402 is configured by tapered surfaces 401a and 401b formed in the deformation portions 401F and 411F of the partial deformation tools 401 and 411, respectively. The inner diameter of the small-diameter end 402N, which is the smallest diameter of the filter deformation holes 402, is larger than the inner diameter of the filter fixing portion 53 in the vent hole 51 of the grommet 50. The filter deformation hole 402 corresponds to the taper insertion deformation path of the present invention.

In addition, in the filter deformation tool 400, a filter placement for placing the ventilation filter 90 (see FIG. 5) in the form before assembly in a state in which the deformation portions 401F and 411F are abutted with each other. A recess 405 is provided. The mounting surface 401Fa of the deforming portion 401F forming the filter mounting recess 405 and the mounting surface 411Fa of the deforming portion 411F are subjected to filter deformation at and near the ventilation portion 91 when the ventilation filter 90 in the form before assembly is placed. The large diameter end 402L of the hole 402 is closed.
On the other hand, of the deformed portions 401F and 411F, lower end surfaces 401Fb and 411Fb positioned below the axis are positioned above the sliding surfaces 401Sa and 411Sa.
When the grommet 50 is disposed in the storage hole 232 of the pedestal 230, the distance between the sensor inner side surface 50 b of the grommet 50 and the lower end surfaces 401 Fb and 411 Fb of the deformable portions 401 F and 411 F is the hole in-hole arrangement portion 71 of the fixing member 70. It is made to become shorter than the axial direction length.

In the assembling process of the seal unit 5 using the filter deforming tool 400, the fixing member 70 held by the rod portion 251 is moved downward along the axis, and the filter contact portion 72 of the fixing member 70 is moved to the filter mounting recess 405. It is made to contact | abut with the ventilation peripheral part 92 of the ventilation filter 90 of the form before an assembly | positioning arrange | positioned in this. Accordingly, the ventilation portion 91 of the ventilation filter 90 closes the filter contact portion 72 which is one end of the in-hole arrangement portion 71 of the fixing member 70.
When the elevating head 250 is further lowered, the ventilation filter 90 and the fixing member 70 are inserted into the filter deformation hole 402 of the filter deformation tool 400 from the large diameter end 402L side, with the ventilation portion 91 at the head. Then, the peripheral portion 93 of the ventilation filter 90 is gradually drawn into the filter deformation hole 402 along the tapered surfaces 401a and 401b.

As a result, the ventilation filter 90 is deformed so that the diameter of the ventilation filter 90 gradually decreases in the filter deformation hole 402 from the large diameter end 402L to the small diameter end 402N, and the ventilation filter 90 has the diameters of the deformation portions 401F and 411F. The small end 402N is smoothly deformed into the pre-insertion configuration 94 (see FIG. 7) along the outer peripheral surface 71a of the in-hole arrangement portion 71 of the fixing member 70 from the peripheral portion 93.
Further, the stress applied to various portions of the ventilation filter 90 at the time of deformation to the pre-insertion configuration 94 can be reduced.

  In particular, also in the present modified embodiment, the surface roughness of the tapered surfaces 401 a and 401 b forming the filter deformation hole 402 in the partial deformation tools 401 and 411 is made smaller than the surface roughness of the inner wall surface 53 a of the grommet 50. Thereby, when deforming the ventilation filter 90 in the pre-assembly form into the pre-insertion form 94, the frictional force generated between the peripheral portion 93 of the ventilation filter 90 and the tapered surfaces 401a and 401b can be further reduced. For this reason, the stress which arises in each place of the ventilation filter 90 can further be reduced.

(Modification 2)
Next, an assembly process of the seal unit 5 according to the second modification of the above embodiment will be described with reference to FIG.
In the assembly process of the seal unit 5 according to the embodiment and the modification 1, when the ventilation filter 90 is inserted into the ventilation hole 51 of the grommet 50, the ventilation filter 90 of the pre-assembly configuration is deformed to the pre-insertion configuration 94. Meanwhile, a part of the ventilation part 91 and the peripheral part 93 of the ventilation filter 90 was inserted into the ventilation hole 51 together with the fixing member 70.
On the other hand, in the assembly process of the seal unit 5 according to the second modification, when the ventilation filter 90 is inserted into the ventilation hole 51 of the grommet 50, the ventilation filter 90 of the pre-assembly configuration is transformed into the pre-insertion configuration 94. After this, the ventilation filter 90 and the fixing member 70 are inserted into the ventilation hole 51 by a series of operations.
The insertion device 500 used in the second modification is different from the insertion device 100 used in the above-described embodiment and the insertion device 300 used in the first modification in the form and operation of the pedestal and the arrangement relationship between the pedestal and the filter deformation tool. However, the other configurations are the same as those of the insertion devices 100 and 300. Therefore, in the second modification, the description of the same parts as those of the above-described embodiment and the first modification will be omitted or simplified, and different parts will be mainly described.

  The form of the filter deformation tool 400 used in the insertion device 500 according to the second modification is the same as that used in the first modification. However, among the partial deformation tools 401 and 411 constituting the filter deformation tool 400, a base insertion recess 406 for temporarily inserting a base 630 described below in a state where the portions below the axis of the deformation portions 401F and 411F are abutted with each other. Used as

  On the other hand, the base 630 includes a grommet holding base 631 and a support 234. The grommet holding base 631 is made of metal. As shown in FIG. 9, the grommet holding base 631 has a receiving hole 632 located at the center and above the axis, and a support receiving hole 633 that communicates with the receiving hole 632 and is located below the axis. Have Among these, the accommodation hole 632 is a cylindrical recess that can accommodate the grommet 50 and has an inner peripheral surface 632 a that contacts the outer peripheral surface 50 c of the grommet 50. The support tool accommodation hole 633 is a cylindrical hole having a diameter smaller than that of the accommodation hole 632, and a columnar support tool 234 is fitted therein. The pedestal 630 is movable in the axial direction (vertical direction in FIG. 9) while holding the grommet 50 supported by the support surface 234a of the support 234. Of the pedestal 630, the outer peripheral surface 631 a of the grommet holding base 631 is smaller in diameter than the inner peripheral surfaces 401 Fc and 411 Fc of the pedestal insertion recess 406.

As can be easily understood when compared with FIG. 8 according to the first modification, the pedestal 630 and the filter deformation tool 400 are different from the first modification in that the sliding portion lower end surfaces 401Sa and 411Sa of the partial deformation tools 401 and 411 are The filter deformation tool 400 is disposed at a position above the pedestal 630 so as to be separated from the upper end surface 631 a located above the grommet holding base 631.
The interval between the pedestal 630 and the filter deforming tool 400 in the axial direction (vertical direction in FIG. 9) is determined by deforming the ventilation filter 90 in the pre-assembly form into the pre-insertion form 94 by the filter deforming tool 400. The relative position between the pedestal 630 and the filter deformation tool 400 is taken into consideration so that the pre-insertion configuration 94 can be maintained and the fixing member 70 can be subsequently inserted into the ventilation hole 51 of the grommet 50.

Next, the assembly process of the seal unit 5 will be described.
Initially, the partial deforming tools 401 and 411 are placed at positions away from each other and from the axis P, the lifting head 250 is positioned above the partial deforming tools 401 and 411, and the base 630 is placed at the partial deforming tools 401 and 411. It is located below the axis. The outer surface 50a of the grommet 50 is directed downward along the axis, and the inner surface 50b of the sensor is positioned above the sliding surface 631a of the grommet holding base 631 so that the grommet 50 is received in the housing hole of the grommet holding base 631. Insert into 632. The grommet 50 inserted into the accommodation hole 632 is in a state where the outer surface 50 a is supported by the support surface 234 a of the support tool 234. Next, the partial deforming tools 401 and 411 are moved in a direction approaching each other and abutted against each other. Further, the ventilation filter 90 in the form before assembly is placed in the filter placement recess 405 of the filter deformation tool 400. Thus, the large diameter end 402L of the filter deformation hole 402 is closed at and near the ventilation portion 91 of the ventilation filter 90. On the other hand, the rod portion 251 of the elevating head 250 is covered with the in-hole arrangement portion 71 of the fixing member 70, and the fixing member 70 is held by the rod portion 251.

  Next, the lifting head 250 is moved downward along the axis, and the fixing member 70 held by the rod portion 251 is moved downward along the axis. Then, the filter contact portion 72 of the in-hole arrangement portion 71 comes into contact with the ventilation peripheral edge portion 92 of the ventilation filter 90 arranged in the filter mounting recess 205, and the ventilation portion 91 is arranged in the hole arrangement portion of the fixing member 70. The filter contact part 72 which is one end of 71 is obstruct | occluded.

  When the elevating head 250 is further lowered below the axial line, the vent portion 90 of the vent filter 90 and the in-hole arrangement portion 71 of the fixing member 70 have a diameter in the filter deformation hole 402 of the filter deformer 400 with the vent portion 91 of the vent filter 90 at the head. Inserted from the large end 402L. Then, the peripheral portion 93 of the ventilation filter 90 moves along the tapered surfaces 401 a and 401 b that form the filter deformation hole 402. As the ventilation filter 90 advances in the filter deformation hole 402 from the large-diameter end 402L above the axis to the small-diameter end 402N below the axis, the deformation progresses so that the diameter gradually decreases, and the outer peripheral surface of the in-hole arrangement portion 71 It is transformed into a pre-insertion configuration 94 that covers 71a.

Next, as shown in FIG. 9, when the ventilation filter 90 is deformed into the pre-insertion configuration 94, the elevating head 250 is stopped from descending, and the state of the pre-insertion configuration 94 is changed to the small diameter ends of the deformation portions 401 </ b> F and 411 </ b> F. This is maintained by holding the peripheral portion 93 at and near 402N. After the elevating head 250 is stopped, the pedestal 630 is raised, and the ventilation filter 90 having the pre-insertion configuration 94 together with the in-hole arrangement portion 71 of the fixing member 70 is inserted into the ventilation hole 51 of the grommet 50. In the middle of insertion, the partial deformation tools 401 and 411 are moved in directions away from the axis P (left and right direction in FIG. 9). The amount of movement of the partial deformation tools 401 and 411 is sufficient to allow the base 630 to be inserted between the partial deformation tools 401 and 411.
After the partial deformation tools 401 and 411 are moved, the pedestal 630 is raised until the collar portion 73 of the fixing member 70 engages with the filter insertion side portion 54 of the grommet 50 and is inserted together with the in-hole arrangement portion 71 of the fixing member 70. The ventilation filter 90 having the front configuration 94 is inserted into the ventilation hole 51 of the grommet 50. Accordingly, the ventilation portion 91 is disposed on the filter closing side portion 52.

Thereafter, the lifting head 250 is reversed and moved upward in the axial direction, and the rod portion 251 is pulled out from the vent hole 51 while the fixing member 70 remains. Thus, the assembly of the seal unit 5 is completed.
According to the assembly of the seal unit 5 described above, since the ventilation filter 90 is in the pre-insertion configuration 94 before being inserted into the ventilation hole 51, the ventilation filter 90 is deformed so much when being inserted into the ventilation hole 51. Since there is no need, resistance due to insertion is small, and excessive tensile stress is not applied to each part of the ventilation filter 90. For this reason, the tearing and crack generation in the ventilation filter 90 can be prevented. Further, it is possible to prevent a decrease in air permeability in the ventilation portion 91 and the like in the ventilation filter 90.

  Further, when the ventilation filter 90 is assembled into the ventilation hole 51 of the grommet 50, the ventilation filter 90 of the pre-assembly configuration is transformed into the pre-insertion configuration 94 immediately before the ventilation filter 90 is inserted into the ventilation hole 51 of the grommet 50. The For this reason, since the ventilation filter 90 in the form before assembly is separately separately formed into a bottomed cylindrical shape and the formed ventilation filter is not inserted, the cost of such molding is also unnecessary.

In the above, the present invention has been described with reference to the embodiment and the first and second modifications. However, the present invention is not limited to the embodiment and the like, and is appropriately modified and applied without departing from the gist thereof. Needless to say, it can be done.
For example, in the embodiment and the first and second modifications, the method for manufacturing the oxygen sensor 1 has been described. However, the method for manufacturing the sensor according to the present invention distributes gas not only through the oxygen sensor 1 but also through its ventilation filter. It can be applied to possible sensors.
Further, in the embodiment and the first and second modifications, the taper portion 203 of the filter deformation hole 202 in the filter deformation tool 200 and the filter deformation hole 402 in the filter deformation tool 400 are set at a constant rate from the large diameter end toward the small diameter end. The taper surface of the truncated cone which is reduced in diameter.
However, the tapered portion of the two-part insertion deformation path formed in the filter deformation tool or the taper shape of the taper insertion deformation path may be an R-surface taper surface that protrudes toward the deformation path. This is because by moving the ventilation filter along this surface, it can be deformed more smoothly.

It is sectional drawing which shows the form and structure of the oxygen sensor 1 which concern on this embodiment. FIG. 2 is an enlarged cross-sectional view showing, in an enlarged manner, a seal unit 5 before being fitted into a proximal end opening 422 of an outer cylinder 42 in the oxygen sensor 1 of FIG. 1. It is sectional drawing which shows the grommet 50 used for the seal unit 5 among the oxygen sensors 1 of FIG. 5 is a cross-sectional view showing a fixing member 70 used in the seal unit 5. FIG. It is the ventilation filter 90 used for the seal unit 5, and is a perspective view which shows the form before the assembly. It is sectional explanatory drawing which shows the state before the ventilation | gas_flowing filter 90 of the form before an assembly | attachment is changed into the form before insertion among the assembly | attachment processes of the seal unit 5. FIG. FIG. 7 is a cross-sectional explanatory view showing a state where the ventilation filter 90 is inserted into the grommet 50 while being deformed into a pre-insertion configuration as in FIG. 6. It is explanatory drawing of the assembly | attachment process of the seal unit 5 which concerns on the modification 1. FIG. It is explanatory drawing of the assembly | attachment process of the seal unit 5 which concerns on the modification 2. FIG.

Explanation of symbols

1 Oxygen sensor (sensor)
51 Ventilation hole (holding hole)
53a (inside of holding hole) inner wall surface 70 fixing member 71 in-hole arrangement part 71a (inside-hole arrangement part) outer peripheral surface 72 filter contact part (one end of in-hole arrangement part)
90 Ventilation filter 91 Ventilation portion 92 Ventilation peripheral edge portion 93 (permeation filter) peripheral portion 94 Pre-insertion configuration 200,400 Filter deformation tool 201, 211, 401, 411 Partial deformation tool 202 Filter deformation hole (two-part insertion deformation path)
402 Filter deformation hole (taper insertion deformation path)
402L large diameter end 402N small diameter end 203 taper part (large diameter part)
203L Large end 203N Small end 203a, 203b Tapered surfaces 401a, 401b (Tapered portion) Tapered surface 204 Cylindrical portion (tubular portion)

Claims (5)

A sensor that allows the gas inside and outside to flow through a ventilation filter,
A sheet-like ventilation filter having breathability and water repellency;
A filter holding member including holding holes communicating with the inside and outside of the sensor;
A fixing member that is disposed in the holding hole of the filter holding member and includes an in-hole arrangement portion having a cylindrical shape with both ends open, and fixing the ventilation filter in the holding hole;
The ventilation filter is configured to block the holding hole while allowing ventilation through a ventilation portion that is a part of the ventilation filter.
Between the outer peripheral surface of the in-hole arrangement portion of the fixing member and the inner wall surface of the holding hole of the filter holding member, at least a part of the ventilation filter other than the ventilation portion is sandwiched. A method for manufacturing a sensor in which the ventilation filter is fixed in the holding hole,
Of the sheet-like ventilation filter, the ventilation portion closes one end of the fixing portion in the hole, and a peripheral portion located around the ventilation portion extends along the outer peripheral surface of the hole arrangement portion. After the air filter is deformed to the form before insertion, the air filter and the fixing member are subsequently inserted into the holding hole of the filter holding member from the air vent side, or While deforming the ventilation filter, insert the deformed portion of the ventilation filter and the fixing member into the holding hole of the filter holding member from the ventilation portion side,
A method for producing a sensor, comprising: a step of closing the holding hole with the ventilation filter, and a step of deforming and inserting the ventilation filter into the holding hole. A method for manufacturing a sensor according to claim 1, comprising:
In the deformation insertion step,
A filter deformation tool having a diameter larger than the holding hole of the filter holding member, and capable of constituting a tapered insertion insertion path that gradually decreases in diameter from the large diameter end toward the small diameter end. Use or
A tapered portion that gradually decreases in diameter from the large-diameter end toward the small-diameter end, and is arranged following the tapered portion, has the same diameter as the small-diameter end, and is the same as the holding hole. Using a filter deformable tool that makes it possible to configure a two-part insertion deformation path having a cylindrical part having a diameter or a large diameter,
In a state where one end of the in-hole arrangement portion of the fixing member is brought into contact with the periphery of the ventilation portion of the sheet-like ventilation filter,
Inserting the in-hole arrangement portion of the ventilation filter and the fixing member from the large-diameter end side toward the small-diameter end side into the tapered insertion deformation path, with the vent portion at the head, or A method for manufacturing a sensor, wherein the ventilation filter is inserted into the cylindrical portion through the tapered portion of the two-part insertion deformation path to deform the ventilation filter into the pre-insertion configuration. A method of manufacturing a sensor according to claim 2,
Among the filter deformation tools,
The method of manufacturing a sensor, wherein the taper insertion deformation path or the surface forming the two-part insertion deformation path is made more slippery than the inner wall surface of the holding hole of the filter holding member. It is a manufacturing method of the sensor given in any 1 paragraph of Claims 1-3,
The ventilation filter is
A method for producing a sensor comprising a resin sheet having a porous fiber structure. It is a manufacturing method of the sensor given in any 1 paragraph of Claims 1-4,
The sensor is a gas sensor that detects at least one of an abundance ratio, a concentration, and a concentration change with respect to a specific gas component in a gas to be measured, and a gas sensor that takes outside air into the gas sensor through the ventilation filter and serves as a reference gas A method for manufacturing a sensor.

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