JP5216047B2 - Gas sensor element manufacturing method and gas sensor manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a gas sensor element and a method for manufacturing a gas sensor.

  As a gas sensor, for example, a gas sensor that is attached to an exhaust pipe of an automobile and detects an oxygen concentration in the exhaust gas is known. For example, the gas sensor has a bottomed cylindrical shape extending in the axial direction, and a base body (solid electrolyte body) in which an annular flange projecting radially outward is formed at a substantially intermediate portion in the axial direction. And a gas sensor element having an electrode made of a noble metal (for example, platinum) formed on the inner surface and the outer surface (see, for example, Patent Document 1).

JP 2007-248123 A

  By the way, Patent Document 1 discloses the following method as a method of forming an electrode made of a noble metal (platinum) on the inner surface of a substrate. First, in the nucleation step, nuclei are attached to the inner surface of the substrate. Specifically, for example, a chloroplatinic acid aqueous solution (platinum concentration: 0.5 g / L) is injected into the substrate and heated, and then the chloroplatinic acid aqueous solution is discharged, and the entire surface of the substrate is platinum chloride. A coating film of an acid aqueous solution is formed. Then, an aqueous solution of hydrazine (concentration: 5% by mass) is poured into the internal space of the substrate, heated to 75 ° C. and left for 30 minutes to precipitate platinum nuclei on the entire inner surface of the substrate. Next, in the plating step, a plating solution prepared by mixing an aqueous platinum complex salt solution (platinum concentration: 15 g / L) and an aqueous solution of hydrazine (concentration: 85% by mass) is injected into the substrate and heated. To deposit platinum in the plating solution. In this way, an electrode made of a noble metal (platinum) is formed on the entire inner surface of the substrate.

  However, the electrode formed on the inner surface of the substrate is not required on the entire inner surface of the substrate. Specifically, the electrode formed on the inner surface of the substrate includes a detection portion, a lead portion, and a terminal connection portion. The detection part is formed on the inner surface of the base on the tip side (bottom side) part (for example, the part located on the tip side of the base part of the base) in the entire circumference or partly in the circumferential direction of the base body. It should be. In addition, the terminal connecting portion may be formed all or partly in the circumferential direction of the base body at the rear end portion in the axial direction of the base body (end portion opposite to the bottom portion). In addition, the lead portion extends from the position of the rear end of the detection portion (the end located on the side opposite to the bottom side of the base) to the position of the tip of the terminal connection portion (end on the bottom side) on the inner surface of the base. It may be formed in a linearly extending form (or a form extending in the axial direction with a cross-sectional arc shape). That is, the lead portion may be formed in a part in the circumferential direction of the base. Thus, it is not necessary to form an electrode made of a noble metal (platinum) on the entire inner surface of the substrate. For this reason, in the method of depositing noble metal on the entire inner surface of the substrate in the plating process and forming electrodes made of noble metal on the entire inner surface of the substrate as in Patent Document 1, expensive and rare noble metals are wasted. Was supposed to do.

  Therefore, the following manufacturing method is considered to be effective. More specifically, prior to the plating process, in the mask jig mounting process, a mask is formed on a mask part (part where no electrode is to be formed) on the inner surface of the substrate that is different from the electrode planned part where the electrode is to be formed. Mount the jig (cover the mask with a mask jig). Thus, in the subsequent plating step, the noble metal is not deposited on the mask portion, but is deposited on the planned electrode portion on the inner surface of the substrate. For this reason, it is thought that the usage-amount of a noble metal can be reduced compared with the case where a noble metal is deposited on the whole inner surface of a base | substrate in a plating process, and the electrode which consists of a noble metal is formed in the whole inner surface of a base | substrate. Yes.

  However, it has been difficult to properly attach the mask jig to the mask portion (appropriately cover the mask portion with the mask jig). This is because the mask portion is located inside the base body, and in order to mount the mask jig on the mask portion, it is necessary to insert the mask jig inside the base body. However, if the curvature radius of the mask jig is larger than the curvature radius of the mask portion, the mask jig may not be inserted inside the base. On the contrary, when the radius of curvature of the mask jig is smaller than the radius of curvature of the mask portion, the mask jig can be inserted inside the base, but the mask jig cannot be fixed to the mask portion, and the mask There is a possibility that the jig is attached to a portion different from the mask portion. Even if the mask jig can be arranged in the mask portion, the outer surface of the mask jig cannot be brought into close contact with the mask portion, and a gap is formed between the mask portion and the outer surface of the mask jig. For this reason, in the subsequent plating step, the plating solution may flow into the gap, and there is a possibility that noble metal is deposited on the mask portion. Therefore, there has been a demand for a technique that allows the mask jig to be properly attached to the mask portion by bringing the outer surface of the mask jig into close contact with the mask portion without any gap.

  The present invention has been made in view of the current situation, and in order to reduce the amount of noble metal used on the inner surface of the substrate, the outer surface of the mask jig is brought into close contact with the mask portion without any gap, and the mask jig is mounted. It is an object of the present invention to provide a method for manufacturing a gas sensor element that can be appropriately attached to a mask portion, and a method for manufacturing a gas sensor.

One aspect of the present invention is to use a nucleation step in which nuclei are attached to the inner surface of a bottomed cylindrical base extending in the axial direction, and a plating solution in which the nuclei act as a catalyst. And a plating step for depositing on the inner surface of the base body, and a method for producing a gas sensor element, wherein the electrode made of the noble metal is formed on the inner surface of the base body. A mask jig mounting step for mounting a mask jig on a mask portion different from the electrode planned portion on which the electrode is to be formed on the surface, and a liquid injection device in the substrate after the mask jig mounting step. And the plating step of depositing the noble metal on the electrode planned portion by injecting the plating solution into the substrate using the liquid injection device, and the mask jig includes the axial direction In a form extending to When the mask jig is mounted on the mask portion, the mask outer surface that is in contact with the mask portion forms an arc in a cross section obtained by cutting the mask jig in a direction perpendicular to the axial direction, and the radius of curvature of the mask outer surface is The mask jig mounting step, wherein the mask jig is elastically deformable in a direction of expansion and contraction, and the curvature radius of the mask outer surface before mounting the mask jig on the mask portion is larger than the curvature radius of the mask portion. Then, while elastically deforming the mask jig in a direction in which the radius of curvature of the mask outer surface is reduced, the mask jig is inserted inside the base, and the mask outer surface is moved by the elastic restoring force of the mask jig. In the method of manufacturing a gas sensor element, the mask jig is brought into close contact with the mask portion and the mask jig is fixed to the mask portion.

  By using the mask jig as described above, when the mask jig is inserted into the base while elastically deforming the mask jig in a direction in which the radius of curvature of the mask outer surface is reduced, the elastic restoring force of the mask jig causes In addition, the mask outer surface can be brought into close contact with the mask part (part where no electrode is to be formed) without gaps, and the mask jig can be fixed to the mask part. Therefore, according to the manufacturing method described above, in the mask jig mounting step, the mask jig is not mounted on a portion other than the mask portion, and there is a gap between the mask portion and the outer surface of the mask jig. It does not occur. For this reason, it is possible to prevent the plating solution from flowing into the gap between the mask portion and the outer surface of the mask jig in the subsequent plating step, and no precious metal is deposited on the mask portion.

Therefore, in the manufacturing method described above, the noble metal can be deposited on the planned electrode portion on the inner surface of the substrate without depositing the noble metal on the mask portion. That is, an electrode made of a noble metal can be formed only on a predetermined electrode portion on the inner surface of the substrate. Thereby, the usage-amount of a noble metal can be reduced appropriately.
Moreover, in the above-described manufacturing method, the mask jig can be appropriately mounted on the inner surface (mask portion) of the base body by the simple method as described above, so that the manufacturing efficiency of the gas sensor element is good and the manufacturing cost is low. .

  The above-mentioned mask jig is made of, for example, an elastic resin (for example, polypropylene, polyethylene, PET), and a mask jig having a shape in which a part of the cylinder in the circumferential direction is cut out over the entire cylinder in the axial direction. You can list the ingredients. The material of the mask jig is not limited to resin, but it is preferable to use a resin mask jig in order to prevent the mask jig from being plated in the plating step.

  By using such a mask jig, an electrode composed of a detection portion, a lead portion, and a terminal connection portion in the following form can be formed as an electrode formed on the inner surface of the base. For example, the detection unit can be formed only on the tip side (bottom side) portion of the inner surface of the base (for example, the portion located on the tip side of the center in the axial direction of the base). Further, the terminal connection portion can be formed on the rear end side (the side opposite to the bottom portion) of the inner surface of the base body. Further, the lead portion is positioned from the position of the rear end of the detection portion (the end portion opposite to the bottom portion side of the substrate) from the position of the inner end surface of the substrate to the tip end (end portion on the bottom side) of the terminal connection portion. Until then, it can be formed in a linearly extending form (or an axially extending cross-sectional arc shape). That is, the lead portion can be formed only in a part in the circumferential direction of the substrate.

When such an electrode is formed, the mask jig exemplified above is, for example, a portion of the inner surface of the base that is adjacent to a portion where the lead portion is to be formed in the circumferential direction (this portion corresponds to the mask portion). To install). Thereby, a linear lead part can be formed in the site | part exposed through the notch part of a mask jig | tool among the inner surfaces of a base | substrate. In addition, the detection part can be formed on the entire inner surface of the base body on the front end side of the mask jig, and the annular terminal is formed on the entire portion positioned on the rear end side of the mask jig. A connection can be formed.
Thus, in the above-described method for manufacturing a gas sensor element, an electrode made of a noble metal can be selectively formed on the inner surface of the substrate at a site where the electrode is required.

  The terminal connecting portion is a portion that is connected to the terminal member of the gas sensor, and is formed at the rear end portion in the axial direction of the base body (the end portion on the opposite side to the bottom portion) in the entire circumference or partly in the circumferential direction of the base body. It should be. For example, the terminal connecting portion may be formed partially in the circumferential direction of the base body with the same width dimension (circumferential dimension) as the lead portion, and may extend in a straight line integrally with the lead portion.

Further, the mask jig mounting step may be performed after the nucleation step and before the plating step, or may be performed before the nucleation step.
In addition, the nuclei to be attached to the inner surface of the substrate in the nucleation process may act as a catalyst for the plating solution later, and examples thereof include platinum, palladium, and rhodium. Further, the noble metal in the plating solution may be any one used as an electrode of a gas sensor, and examples thereof include platinum, palladium, rhodium and the like. The core and the noble metal in the plating solution may be the same material or different materials.

  Furthermore, in the method for manufacturing the gas sensor element described above, the length of the arc on the outer surface of the mask is more than half of the peripheral length of the cylindrical portion including the mask portion in the circumferential direction on the inner surface of the base. A gas sensor element manufacturing method that is long and equal to or less than the circumferential length of the cylindrical portion is preferable.

  In the above manufacturing method, as the mask jig, the length of the arc on the outer surface of the mask (the arc in the cross section obtained by cutting the mask jig in a direction orthogonal to the axial direction) is the circumferential direction of the mask portion of the inner surface of the substrate. A mask jig that is longer than ½ of the circumferential length of the cylindrical portion (circumferential length around the axis) and not more than the circumferential length of the cylindrical portion is used. By using the mask jig having such a shape, the mask jig can be securely fixed to the mask portion by making the mask outer surface closely contact the mask portion without any gap by the elastic restoring force of the mask jig. Therefore, when the mask jig is mounted, there is no gap between the mask portion and the outer surface of the mask jig.

  Further, in any of the above gas sensor element manufacturing methods, prior to the plating step, a plating resist film is formed on a plating resist portion excluding the predetermined electrode portion and the mask portion on the inner surface of the substrate. It is preferable to provide a gas sensor element manufacturing method comprising: a plating resist film forming step to be performed; and a burnout step of burning the plating resist film after the plating step.

  In the above-described manufacturing method, prior to the plating step, in the plating resist film forming step, a plating resist film is formed on a portion (plating resist portion) on the inner surface of the substrate excluding the planned electrode portion and the mask portion. Thereby, in the subsequent plating step, in addition to the portion (mask portion) where the mask jig is mounted on the inner surface of the substrate, no precious metal is deposited on the portion where the plating resist film is formed (plating resist portion). The noble metal can be deposited only on the electrode portion on the inner surface of the substrate. For this reason, the usage-amount of a noble metal can be reduced further.

  In addition, the above-described method for manufacturing a gas sensor element includes a burnout process for burning the plating resist film after the plating process. Thereby, the plating resist film which becomes unnecessary after a plating process can be removed appropriately. Also, the plating resist film removal method by burning can remove the plating resist film more easily and appropriately than the method of peeling and removing the plating resist film.

  Moreover, as a method of forming a plating resist film, for example, a method of forming a plating resist film by applying a plating resist (coating material) to the plating resist portion of the inner surface of the substrate and curing it is exemplified. . Examples of the plating resist (paint) include an acrylic mask material, an emulsion, a dye, and a ceramic baking binder paste.

Note that the plating resist film is extremely effective when it is not desired to form an electrode on a portion of the inner surface of the base where it is difficult to mount the mask jig (for example, the bottom of the base). It is possible to form a plating resist film (apply a plating resist) even at a portion of the inner surface of the substrate where it is difficult to mount the mask jig (for example, the bottom (tip surface) of the substrate). Therefore, plating (electrode formation) on the part can be prevented.
Further, the plating resist film forming step may be performed before the mask jig mounting step or after the mask jig mounting step.

  Further, the gas sensor element manufacturing method described above may be a gas sensor element manufacturing method in which, in the plating resist film forming step, a plating resist film made of an organic substance not containing a metal component is formed as the plating resist film.

  When the metal component is contained in the plating resist film, the metal component remains on the inner surface of the substrate even after the plating resist film is burned out in a later burning step. This remaining metal component may affect the characteristics of the gas sensor element. For this reason, it is not preferable that the plating resist film contains a metal component.

  On the other hand, in the gas sensor element manufacturing method described above, in the plating resist film forming step, a plating resist film made of an organic substance not containing a metal component is formed. For this reason, in the burn-out process, the above-mentioned problem that “the metal component remains on the inner surface of the substrate (the portion where the plating resist film was formed)” does not occur, and the plating resist film made of an organic material is appropriately burned off. be able to.

  In addition, as a method of forming a plating resist film made of an organic material that does not contain a metal component, for example, a plating resist (paint) made of an organic material that does not contain a metal component is removed from a portion of the inner surface of the substrate excluding a predetermined electrode portion. And a method of forming a plating resist film made of an organic material that does not contain a metal component.

  Examples of the plating resist (paint) made of an organic material not containing a metal component include acrylic mask materials, emulsions, dyes, ceramic baking binder pastes, and the like. Among these, as the emulsion, an acrylic emulsion (specifically, for example, Cybinol CA-1108 (trade name, manufactured by Saiden Chemical Co., Ltd.) can be exemplified.

Another aspect of the present invention includes a gas sensor element, a metal shell for holding the gas sensor element, a manufacturing method of a gas sensor having, to produce the gas sensor element by the manufacturing method of the preceding SL any of the gas sensor element, Thereafter, the gas sensor manufacturing method includes a step of holding the gas sensor element inside the metal shell.

The above-described gas sensor manufacturing method includes the steps of manufacturing the gas sensor element by the above-described gas sensor element manufacturing method and then holding the gas sensor element inside the metal shell . According to the gas sensor element manufacturing method described above, the amount of noble metal used can be reduced when an electrode made of a noble metal is formed on the inner surface of the substrate. Therefore, according to the above-described gas sensor manufacturing method, it is possible to manufacture a gas sensor in which the amount of noble metal used is reduced.

1 is a top view of a base according to Example 1. FIG. It is a longitudinal cross-sectional view of the same base | substrate, and is equivalent to the BB arrow sectional drawing of FIG. It is a longitudinal cross-sectional view of the same base | substrate, and is corresponded in CC sectional view taken on the line of FIG. It is explanatory drawing of the nucleation process concerning Example 1,2. It is a front view of the mask jig concerning Examples 1 and 2. FIG. It is sectional drawing of the mask jig | tool and is equivalent to the EE arrow sectional drawing of FIG. FIG. 3 is a front view of the mask jig (a state in which the mask jig is elastically deformed in a direction in which the curvature radius of the mask outer surface is reduced). FIG. 8 is a cross-sectional view of the same mask jig (a state in which the mask outer surface is elastically deformed in a direction in which the radius of curvature of the mask is reduced), and corresponds to a cross-sectional view taken along line FF in FIG. 7. It is explanatory drawing of the mask jig | tool mounting process concerning Example 1. FIG. It is explanatory drawing of the mask jig | tool mounting process. It is explanatory drawing of the mask jig | tool mounting process. 3 is an explanatory diagram of a plating process according to Example 1. FIG. It is explanatory drawing of the same plating process. It is explanatory drawing of the same plating process. 1 is a cross-sectional view of a gas sensor element according to Example 1. FIG. It is sectional drawing of the same gas sensor element. It is a longitudinal cross-sectional view of the gas sensor concerning Examples 1 and 2. FIG. 6 is a top view of a base according to Example 2. FIG. It is a longitudinal cross-sectional view of the same base, and corresponds to a cross-sectional view taken along the line KK in FIG. It is a longitudinal cross-sectional view of the same base, and corresponds to a cross-sectional view taken along line JJ in FIG. It is explanatory drawing of the plating resist film formation process concerning Example 2, and a mask jig | tool mounting process. It is explanatory drawing of the same plating resist film formation process and a mask jig | tool mounting process. It is explanatory drawing of the same plating resist film formation process and a mask jig | tool mounting process. 6 is an explanatory diagram of a plating process according to Example 2. FIG. It is explanatory drawing of the same plating process. It is explanatory drawing of the same plating process. It is explanatory drawing of the burning-out process concerning Example 2. FIG. It is explanatory drawing of the same burning-out process.

Example 1
Next, Example 1 of the present invention will be described with reference to the drawings.
First, the base 1 used in the method for manufacturing the gas sensor element according to the first embodiment will be described. As shown in FIGS. 1 to 3, the base body 1 extends along the axis AX, and has a bottomed cylindrical shape with one end closed and the other end opened. Here, in the base body 1, the end on the closed side is referred to as a front end 1 s, and the end on the opened side is referred to as a rear end 1 e.

  An annular flange 2 protruding outward in the radial direction is formed at a substantially middle portion of the base body 1 in the axial direction (the direction along the axis AX, the vertical direction in FIGS. 2 and 3). The flange 2 is used to engage the base body 1 in a metal shell 31 of a gas sensor 30 described later.

  Of the inner surface 1n of the base body 1, a portion where the electrode 21 is to be formed (a portion where an electrode is to be formed) is the planned electrode portion 3. The planned electrode portion 3 includes a scheduled detection portion 3g scheduled to be the detection portion 21g of the electrode 21, a planned lead portion 3s scheduled to be the lead portion 21s, and a planned terminal connection portion 3t scheduled to be the terminal connection portion 21t. Consists of.

  Among these, the detection scheduled part 3g is located in all the portions of the inner surface 1n of the base body 1 that are located on the tip side (the tip part 1s side, the lower side in FIGS. 2 and 3) from the tip part 2s of the collar part 2. is there. That is, the scheduled detection part 3g is a part of the inner surface 1n of the base body 1 that is located on the tip side of the tip part 2s of the collar part 2 and extends over the entire circumference in the circumferential direction of the base body 1.

  Further, the terminal connection planned portion 3t is a portion located on the rear end side (rear end portion 1e side) of the inner surface 1n of the base 1 and is an annular portion covering the entire circumference in the circumferential direction of the base 1.

  Further, the planned lead portion 3s is scheduled to be connected to the terminal from the position of the rear end (the end located on the rear end portion 1e side of the base body 1, the upper end in FIG. 2) of the inner surface 1n of the base body 1. The portion of the form extending in a linear manner (specifically, the form extending in the axial direction with a cross-sectional arc shape) to the position of the tip of the portion 3t (the end located on the tip 1s side of the base 1, the lower end in FIG. 2) It is. The planned lead portion 3 s is a partial range D (a range indicated by an arrow in FIG. 1, an arc having a central angle of 80 °) in the circumferential direction of the base 1.

Further, a portion of the inner surface 1n of the substrate 1 excluding the planned electrode portion 3 (the planned detection portion 3g, the planned lead portion 3s, and the planned terminal connection portion 3t) is the mask portion 4 (non-electrode planned portion). . The mask portion 4 is a portion of the inner surface 1n of the base body 1 that is adjacent to the planned lead portion 3s in the circumferential direction of the base body 1. Specifically, from the position of the rear end of the planned detection portion 3g to the position of the front end of the terminal connection planned portion 3t, the cross-section arc shape (circular arc with a central angle of 280 °) is formed in the axis AX direction (vertical direction in FIGS. 2 and 3) ).
2 and 3, the boundary between the planned electrode portion 3 and the mask portion 4 is indicated by a broken line.

As such a substrate 1, for example, using a known press molding method, a solid electrolyte body mainly composed of zirconia is formed into a bottomed cylindrical molded body, and then this is fired at 1500 ° C. for about 2 hours. Things can be used.
It should be noted that the peripheral length (around the axis AX) of the cylindrical portion 1m (cylindrical portion extending in the axis AX direction from the front end to the rear end of the mask portion 4) of the inner surface 1n of the base body 1 in the circumferential direction is included. Circumference length) is constant at L2 (see FIG. 1). The radius of curvature of the mask portion 4 is constant at R2 (see FIGS. 1 and 2).

Next, a method for manufacturing the gas sensor element according to the first embodiment will be described.
First, an electrode (not shown) is formed on the outer surface 1h of the base 1 using a known method (for example, see Japanese Patent Application Laid-Open No. 2007-248123).

  Next, in the nucleation step, nuclei are attached to the inner surface 1 n of the substrate 1. Specifically, first, as shown in FIG. 4, the chloroplatinic acid aqueous solution 8 (platinum concentration: 0.5 g / L) is injected into the internal space S of the substrate 1 using the liquid injection device 11. In the first embodiment, the liquid reservoir member 13 made of silicon rubber is attached to the rear end 1 e of the base 1, and the chloroplatinic acid aqueous solution 8 filling the internal space S of the base 1 is the internal space S of the base 1. The chloroplatinic acid aqueous solution 8 is poured until it overflows and reaches the liquid storage member 13.

  Next, the chloroplatinic acid aqueous solution 8 filling the internal space S of the substrate 1 is heated. Thereby, a coating film of an aqueous solution of chloroplatinic acid can be formed on the inner surface 1 n of the substrate 1. Thereafter, the chloroplatinic acid aqueous solution 8 injected into the internal space S of the substrate 1 is discharged to the outside of the substrate 1 using the liquid injection device 11.

  Next, a hydrazine aqueous solution 9 (concentration: 5 mass%) is injected into the internal space S of the substrate 1 using the liquid injection device 11. At this time, the hydrazine aqueous solution 9 filling the internal space S of the base body 1 overflows from the internal space S of the base body 1 and reaches the liquid storage member 13 with the liquid storage member 13 attached to the rear end 1 e of the base body 1. Until then, the hydrazine aqueous solution 9 is poured. Thereafter, the injected hydrazine aqueous solution 9 is heated and left at a temperature of 75 ° C. for 30 minutes. Thereby, platinum nuclei can be deposited on the inner surface 1 n of the substrate 1. Thereafter, the hydrazine aqueous solution 9 injected into the internal space S of the substrate 1 is discharged to the outside of the substrate 1 using the liquid injection device 11.

Next, it progresses to a mask jig | tool mounting process, and the mask jig | tool 18 is mounted | worn to the mask part 4 among the inner surfaces 1n of the base | substrate 1 (refer FIGS. 9-11).
Here, the mask jig 18 will be described in detail. As shown in FIGS. 5 and 6, the mask jig 18 has a curved plate shape extending in the direction of the axis AX. The mask jig 18 has a mask outer surface 18 b that comes into contact with the mask portion 4 when the mask jig 18 is attached to the mask portion 4. 5 and 7, the vertical direction coincides with the axis AX direction (direction in which the axis AX extends).

  The mask outer surface 18b forms an arc in a cross section (corresponding to the cross section of FIG. 6) cut in a direction orthogonal to the axis AX direction when the mask jig 18 is mounted on the mask portion 4. The length L1 of the arc is longer than 1/2 of the circumferential length L2 of the cylindrical portion 1m including the mask portion 4 in the circumferential direction on the inner surface 1n of the base 1, and shorter than L2. That is, the relationship (L2 / 2) <L1 <L2 is satisfied. Further, the curvature radius R1b of the mask outer surface 18b (the mask outer surface 18b in the state shown in FIG. 6) before the mask jig 18 is mounted on the mask portion 4 is made larger than the curvature radius R2 of the mask portion 4.

  The mask jig 18 is made of polypropylene and can be elastically deformed in a direction in which the radius of curvature R1 of the mask outer surface 18b expands or contracts. Accordingly, as shown in FIGS. 7 and 8, the mask jig 18 is elastically deformed in a direction in which the curvature radius R1 of the mask outer surface 18b is reduced (for example, the curvature radius R1 of the mask outer surface 18b is changed to the curvature of the mask portion 4). R1c equivalent to the radius R2).

  For this reason, in the mask jig mounting step of the first embodiment, the mask jig 18 is elastically deformed in the direction in which the curvature radius R1 of the mask outer surface 18b is reduced (the curvature radius R1 of the mask outer surface 18b is set to the mask portion 4). When the mask jig 18 is inserted into the inside of the base body 1 (to a position overlapping the mask portion 4) (refer to FIGS. 9 to 11) while the curvature radius R2 or less, the subsequent elastic restoring force of the mask jig 18 The mask outer surface 18b is brought into close contact with the mask portion 4 (at this time, the curvature radius of the mask outer surface 18b is R1c equivalent to the curvature radius R2 of the mask portion 4, see FIG. 9), and the mask jig 18 is attached to the mask portion. 4 can be fixed. Thus, in the mask jig mounting step of the first embodiment, the mask jig 18 is mounted on the mask portion 4 of the inner surface 1n of the substrate 1 (the mask portion 4 is covered with the mask jig 18) (FIG. 9 to 11).

  FIG. 9 corresponds to a top view of the base body 1 on which the mask jig 18 is mounted (a view of the base body 1 viewed from the rear end portion 1e side in the axis AX direction). FIG. 10 corresponds to a cross-sectional view taken along the line HH in FIG. Moreover, FIG. 11 is corresponded in the GG arrow sectional drawing of FIG.

  Next, the process proceeds to a plating step, and the noble metal (platinum) in the plating solution 12 is removed from the inner surface 1n of the substrate 1 by using the plating solution 12 in which the nuclei deposited on the inner surface 1n of the substrate 1 act as a catalyst. It deposits on the electrode planned part 3 (detection scheduled part 3g, lead planned part 3s, and terminal connection scheduled part 3t). Specifically, as shown in FIG. 12, the plating solution 12 is injected into the internal space S of the substrate 1 using the liquid injection device 15. At this time, the plating solution 12 filling the internal space S of the base body 1 overflows from the internal space S of the base body 1 and reaches the liquid storage member 13 with the liquid storage member 13 attached to the rear end 1 e of the base body 1. Then, the plating solution 12 is injected.

In Example 1, as the plating solution 12, a plating solution prepared by mixing a platinum complex salt aqueous solution (platinum concentration: 15 g / L) and an aqueous solution of hydrazine (concentration: 85% by mass) is used.
Next, the plating solution 12 injected into the internal space S of the substrate 1 is heated and then left for a predetermined time. Thereby, platinum in the plating solution 12 can be deposited on the inner surface 1 n (the electrode planned portion 3) of the substrate 1. Thereafter, the plating solution 12 injected into the internal space S of the substrate 1 is discharged to the outside of the substrate 1 using the liquid injection device 15.

  In the first embodiment, as described above, the mask jig 18 is mounted on the mask portion 4 excluding the planned electrode portion 3 on the inner surface 1n of the base 1 in the mask jig mounting step prior to the plating step. (The mask part 4 is covered with the mask jig 18). For this reason, in the above-described plating step, the inner surface 1n of the substrate 1 is not deposited on the portion (mask portion 4) provided with the mask jig 18 on the inner surface 1n of the substrate 1 without depositing noble metal (platinum). Among them, the noble metal (platinum) can be deposited only on the portion (the planned electrode portion 3) where the mask jig 18 is not provided.

Therefore, as shown in FIGS. 13 and 14, the electrode 21 made of noble metal (platinum) is formed only on the portion (the planned electrode portion 3) where the mask jig 18 is not provided on the inner surface 1 n of the substrate 1. Can do. In detail, the detection part 21g of the electrode 21 can be formed in the detection scheduled part 3g of the electrode planned part 3, and the lead part 21s of the electrode 21 can be formed in the planned lead part 3s of the electrode planned part 3. In addition, the terminal connection portion 21 t of the electrode 21 can be formed in the terminal connection planned portion 3 t of the electrode planned portion 3.
FIG. 13 is a cross-sectional view of the plated base body 20B (base body 1 on which a precious metal is deposited on the planned electrode portion 3) cut at the same position as in FIG. FIG. 14 is a cross-sectional view of the plated substrate 20B cut at the same position as FIG.

  As described above, in the manufacturing method of the first embodiment, the electrode 21 made of the noble metal is selectively formed on the inner surface 1n of the substrate 1 where the electrode is required (the detection portion 21g, the lead portion 21s, and the terminal connection portion 21t). Can be formed. For this reason, in the first embodiment, the amount of noble metal used is reduced as compared with the case where the noble metal is deposited on the entire inner surface of the substrate in the plating step to form an electrode made of the noble metal on the entire inner surface of the substrate. Can do.

Next, the process proceeds to a mask jig removing step, and the mask jig 18 is removed from the plated substrate 20B (see FIGS. 15 and 16). Since the mask jig 18 is only fixed to the mask portion 4 by its own elastic restoring force, the mask jig 18 can be easily detached from the plated substrate 20B.
FIG. 15 is a cross-sectional view of the plated substrate 20B cut at the same position as FIG. FIG. 16 is a cross-sectional view of the plated substrate 20B cut at the same position as FIG.

  Thereafter, the process proceeds to a reduction process, and the plated substrate 20B is heat-treated in a reducing atmosphere at 750 ° C. As a result, oxygen adsorbed on the surface of the electrode 21 (platinum plating) is removed, and the electrode 21 (platinum plating) is baked on the inner surface 1n of the base 1 to form the electrode 21 having predetermined characteristics. it can. In this manner, the gas sensor element 20 (see FIGS. 15 and 16) of Example 1 is completed.

  The gas sensor element 20 manufactured as described above can be used for manufacturing a gas sensor in the same manner as a conventional gas sensor element. In Example 1, the gas sensor 30 was manufactured by using a gas sensor element 20 by a known assembly method (for example, see Japanese Patent Application Laid-Open No. 2004-053425). FIG. 17 shows an example of a gas sensor 30 using the gas sensor element 20 manufactured by the manufacturing method of the present invention.

  As shown in FIG. 17, the gas sensor 30 includes a gas sensor element 20 and a cylindrical metal shell 31 that surrounds the gas sensor element 20. Further, the gas sensor 30 includes an inner terminal member 32 and a heater 33. The heater 33 is disposed inside the gas sensor element 20, and is held by the inner terminal member 32. Specifically, the heater 33 is held by the inner terminal member 32 in a state in which the tip 33b is in contact with the electrode 21 (detector 21g) of the gas sensor element 20.

  The metal shell 31 engages and holds the collar portion 2 of the gas sensor element 20 (base 1) by interposing metal packings 34, 35, 36, insulators 37, 38, and talc powder 39 inside the hollow cylinder. ing. As a result, the gas sensor element 20 is held by the metal shell 31 with the tip 20b protruding from the tip-side opening 31b of the metal shell 31.

  Further, a protector 40 is attached to the metal shell 31 so as to cover the tip portion 20b of the gas sensor element 20 protruding from the tip-side opening 31b of the metal shell 31. The protector 40 has a double structure having an outer protector 40a and an inner protector 40b. The outer protector 40a and the inner protector 40b are formed with a plurality of vent holes through which exhaust gas passes. For this reason, the exhaust gas introduced from the vent of the protector 40 can be brought into contact with the detection part of the electrode (hereinafter also referred to as the outer electrode) formed on the outer surface of the gas sensor element 20.

  In addition, the detection part of an outer electrode is formed in the site | part in which the detection part 21g of the electrode 21 exists in the thickness direction of the base | substrate 1 among the outer surfaces 1h of the base | substrate 1, for example. That is, the detection part of an outer electrode is formed in all the parts located in the front end side (lower side in FIG.2 and FIG.3) from the front-end | tip part 2s of the collar part 2 among the outer surfaces 1h of the base | substrate 1, for example. Yes. Further, in the gas sensor 30 of the first embodiment, the exhaust gas introduced into the gas sensor 30 from the vent of the protector 40 by the sealing by the packings 34 and 35 is on the rear end side of the flange portion 2 of the gas sensor element 20 ( The upper side in FIG. 17 is not taken in.

  On the other hand, in the metal shell 31, the tip end portion of the cylindrical metal outer cylinder 41 is fixed to the connection portion 31c on the rear end side (upper side in FIG. 17) from the hexagonal portion 31h by laser welding from the outside. Yes. Further, the rear end side opening of the metal outer cylinder 41 is swaged and sealed by fitting a grommet 42 made of fluoro rubber. A separator 43 made of insulating alumina ceramic is provided on the front end side (lower side in FIG. 17) of the grommet 42. Sensor output lead wires 44 and 45 and heater lead wires 46 and 47 are inserted into the through hole of the grommet 42 and the through hole (holding hole 43 d) of the separator 43.

  A through hole along the axis AX is also formed in the center of the grommet 42. A metal pipe 49 covered with a sheet-like filter 48 having both water repellency and air permeability is fitted into the through hole. Thereby, the air existing outside the gas sensor 30 can be introduced into the metal outer cylinder 41 through the filter 48 and further introduced into the gas sensor element 20 to be brought into contact with the detection part 21 g of the electrode 21. .

  In this gas sensor 30, when a predetermined voltage is applied between the outer electrode and the electrode 21 (inner electrode), the oxygen concentration in the exhaust gas contacting the outer electrode detector and the detector of the electrode 21 (inner electrode) A current corresponding to the concentration difference from the oxygen concentration in the atmosphere in contact with 21 g flows. By detecting this current value, the oxygen concentration in the exhaust gas can be grasped.

  Further, the outer terminal member 50 made of a stainless steel plate has an outer fitting portion 50p in which the cross section in the direction perpendicular to the axis AX is substantially C-shaped, and a separator inserted from the vicinity of the center of the rear end side of the outer fitting portion 50p to the rear end side. Part 50s and a connector part 50c located on the rear end side. Among these, the connector part 50c grips the core wire of the sensor output lead wire 45 by caulking, and electrically connects the outer terminal member 50 and the sensor output lead wire 45.

Further, the separator insertion portion 50s is inserted into the separator 43, and the separator contact portion 50d that branches and protrudes from the separator insertion portion 50s elastically contacts the holding hole 43d. 50 itself is held in the separator 43.
Further, the outer fitting portion 50p is in contact with an electrode (outer electrode) formed on the outer surface of the gas sensor element 20. Thereby, the outer electrode and the outer terminal member 50 are electrically connected.

  The inner terminal member 32 made of a stainless copper plate includes an element insertion portion 32k having a substantially horseshoe-shaped cross section in the direction orthogonal to the axis AX, and a separator insertion portion 32s extending from the vicinity of the center of the rear end side of the element insertion portion 32k to the rear end side. And a connector portion 32c located on the rear end side. Among these, the connector part 32 c grips the core wire of the sensor output lead wire 44 by caulking, and electrically connects the inner terminal member 32 and the sensor output lead wire 44.

The separator insertion portion 32 s is inserted into the separator 43, and a separator contact portion 32 d that branches and protrudes from the separator insertion portion 32 s elastically contacts the holding hole 43 d, and the inner terminal member 32. It holds itself in the separator 43.
The element insertion portion 32k of the inner terminal member 32 is inserted into the gas sensor element 20 and is in contact with the terminal connection portion 21t of the electrode 21. Thereby, the terminal connection part 21t of the electrode 21 and the inner terminal member 32 are electrically connected.

(Example 2)
Next, Embodiment 2 of the present invention will be described with reference to the drawings.
In addition, the gas sensor of the present Example 2 differs in the shape of the electrode detection part from the gas sensor of Example 1 (therefore, the shape of the scheduled detection part of the planned electrode part of the substrate is different), and other parts Is the same. Further, the manufacturing method of the second embodiment is different from the manufacturing method of the first embodiment only in the method of forming the detection part, and the other is the same. Therefore, here, the description will focus on the differences from the first embodiment, and the description of the same points as in the first embodiment will be omitted or simplified.

  First, the base | substrate 101 used for the manufacturing method of the gas sensor element concerning the present Example 2 is demonstrated. The base body 101 of the second embodiment is different from the base body 1 of the first embodiment in the shape (range) of the planned electrode portion 103 (specifically, the planned detection portion 103g) (see FIGS. 18 to 20). Specifically, in the base 101 of the second embodiment, the portion (tip surface 101p) on the tip side of the base in the scheduled detection portion 3g of the first embodiment is formed on the plating resist portion 105 (later, a plating resist film is formed). It has been changed to (part). As a result, in the base body 101 of the second embodiment, the detection scheduled portion 103g is located on the inner surface 101n of the base body 101 from the position of the front end portion 102s of the flange 102 to the front end side (the front end portion 101s side, FIGS. 19 and 20). It becomes a cylindrical part extended toward the lower side.

  The planned electrode portion 103 of the second embodiment includes a planned detection portion 103g scheduled to be the detection portion 121g of the electrode 121 and a planned lead portion 103s planned to be the lead portion 121s (equivalent to the planned lead portion 3s of the first embodiment). Part) and a terminal connection planned part 103t (a part equivalent to the terminal connection planned part 3t of Example 1) to be the terminal connection part 121t (see FIGS. 18 to 20).

  Further, portions of the inner surface 101n of the substrate 101 excluding the planned electrode portion 103 (the planned detection portion 103g, the planned lead portion 103s, and the planned terminal connection portion 103t) are the mask portion 104 and the plating resist portion 105 (non-electrode). Planned part). The mask part 104 is a part equivalent to the mask part 4 of the first embodiment. The plating resist portion 105 is a portion of the inner surface 101n of the base 101 that coincides with the tip surface 101p, and has a substantially hemispherical shape.

In FIG. 19 and FIG. 20, the boundaries between the planned electrode portion 3, the mask portion 4, and the plating resist portion 105 are indicated by broken lines.
Further, the circumferential length (circumferential length around the axis AX) of the cylindrical portion 101m (a portion equivalent to the cylindrical portion 1m of Example 1) of the inner surface 101n of the base body 101 including the mask portion 104 in the circumferential direction is: L2 is constant (see FIG. 18). Further, the radius of curvature of the mask portion 104 is constant at R2 (see FIGS. 19 and 20).

Next, a method for manufacturing the gas sensor element according to the second embodiment will be described.
First, in the same manner as in Example 1, electrodes (not shown) are formed on the outer surface 110h of the base 101. Next, in the nucleation step, nuclei are attached to the inner surface 101n of the substrate 101 in the same manner as in Example 1 (see FIG. 4).

  Next, it progresses to a plating resist film formation process, and forms the plating resist film 110 in the plating resist part 105 among the inner surfaces 101n of the base | substrate 101 (refer FIGS. 21-23). Specifically, a plating resist 110b is applied to the plating resist portion 105 and is cured by heating and drying to form the plating resist film 110. In Example 2, Cybinol CA-1108 (trade name, manufactured by Saiden Chemical Co., Ltd.), which is an acrylic emulsion, is used as the plating resist 110b. The plating resist 110b is a plating resist (paint) made of an organic material that does not contain a metal component. Therefore, in the second embodiment, the plating resist film 110 is a plating resist film made of an organic material that does not contain a metal component.

Thereafter, the process proceeds to a mask jig mounting step, and the mask jig 18 is mounted on the mask portion 104 of the inner surface 101n of the base 101 in the same manner as in the first embodiment (see FIGS. 21 to 23).
FIG. 21 corresponds to a top view of the base body 101 on which the mask jig 18 is mounted (a view of the base body 101 viewed from the rear end 101e side in the axis AX direction). FIG. 22 corresponds to a cross-sectional view taken along line MM in FIG. FIG. 23 corresponds to a cross-sectional view taken along line LL in FIG.

  Next, the process proceeds to the plating step, and the noble metal (platinum) in the plating solution 12 is deposited on the inner surface 101 n of the substrate 101 in the same manner as in the first embodiment.

  In the second embodiment, as described above, prior to the plating process, in the plating resist film forming process, the plating resist film 105 on the inner surface 101n of the substrate 101, which is different from the planned electrode part 103, is applied to the plating resist film. 110 is formed. Further, prior to the plating process, in the mask jig mounting process, the mask jig 18 is mounted on the mask portion 104 of the inner surface 101n of the base body 101 excluding the planned electrode portion 103 and the plating resist portion 105.

  For this reason, in the above-described plating step, noble metal (platinum) is deposited on the portion of the inner surface 101n of the substrate 101 where the mask jig 18 and the plating resist film 110 are provided (mask portion 104 and plating resist portion 105). In this case, noble metal (platinum) can be deposited only on the portion (the planned electrode portion 103) where the mask jig 18 and the plating resist film 110 are not provided on the inner surface 101n of the substrate 101.

  Therefore, as shown in FIGS. 25 and 26, an electrode made of a noble metal (platinum) is provided only on a portion (the planned electrode portion 103) where the mask jig 18 and the plating resist film 110 are not provided in the inner surface 101n of the base 101. 121 can be formed. In detail, the detection part 121g of the electrode 121 can be formed in the detection scheduled part 103g of the electrode planned part 103, and the lead part 121s of the electrode 121 can be formed in the planned lead part 103s of the electrode planned part 103. In addition, the terminal connection portion 121t of the electrode 121 can be formed in the terminal connection planned portion 103t of the electrode planned portion 103.

  25 is a cross-sectional view of the plated base 120B (the base 101 on which the noble metal is deposited on the pre-electrode portion 103) cut at the same position as FIG. FIG. 26 is a cross-sectional view of the plated base 120B cut at the same position as FIG.

  As described above, in the manufacturing method according to the second embodiment, the electrode 121 made of the noble metal (the detection unit 121g, the lead unit 121s, and the terminal connection unit 121t) is selectively formed on the inner surface 101n of the base body 101 at a site where an electrode is required. Can be formed. For this reason, in Example 2, the amount of noble metal used is reduced as compared with the case where a noble metal is deposited on the entire inner surface of the substrate in the plating step to form an electrode made of the noble metal on the entire inner surface of the substrate. Can do.

  In particular, in the manufacturing method of the second embodiment, a plating resist is applied to a portion of the inner surface 101n of the base body 101 where it is difficult to mount the mask jig 18 (specifically, the tip surface 101p). The formation of the resist film is excellent in that the noble metal plating on the part (specifically, the tip surface 101p) can be prevented. As described above, the manufacturing method according to the second embodiment is extremely effective when it is not desired to form an electrode (noble metal plating) on a portion of the inner surface of the substrate where it is difficult to mount the mask jig.

  Next, the process proceeds to a mask jig removing step, and the mask jig 18 is removed from the plated substrate 120B in the same manner as in the first embodiment.

Next, proceeding to the burning step, the plated substrate 120B from which the mask jig 18 was removed was heat-treated in an air atmosphere at about 500 ° C., and the plating resist film 110 was burned away. As a result, the plating resist film 110 could be appropriately removed from the inner surface 101n (plating resist portion 105) of the base 101 (see FIGS. 27 and 28). Thus, by burning out the plating resist film, the plating resist film can be easily and appropriately removed as compared with the case where the plating resist film is peeled off and removed.
27 is a cross-sectional view of the plated substrate 120B cut at the same position as FIG. FIG. 28 is a cross-sectional view of the plated substrate 120B taken at the same position as FIG.

  By the way, if a metal component is contained in the plating resist film, the metal component may remain on the inner surface of the substrate even after the plating resist film is burned out in the burning step. This remaining metal component may affect the characteristics of the gas sensor element. For this reason, it is not preferable that the plating resist film contains a metal component.

  On the other hand, in the second embodiment, as described above, the plating resist film 110 made of an organic substance not containing a metal component is formed in the plating resist film forming step. For this reason, in the burn-out process, the above-mentioned problem that “the metal component remains on the inner surface of the substrate (the portion where the plating resist film was formed)” does not occur, and the plating resist film 110 made of an organic material is appropriately burned out. Can be made.

  Next, proceeding to a reduction treatment step, the plated substrate 120B from which the plating resist film 110 has been burned out is heat-treated in a reducing atmosphere at 750 ° C. Thus, oxygen adsorbed on the surface of the electrode 121 (platinum plating) is removed, and the electrode 121 (platinum plating) is baked on the inner surface 101n of the base 101 to form the electrode 121 having predetermined characteristics. it can. In this way, the gas sensor element 120 (see FIGS. 27 and 28) of the second embodiment is completed.

  By the way, if the plated substrate 120B is exposed to a temperature environment close to or higher than the heating temperature (750 ° C.) in the reduction process in the previous burning process, the characteristics of the electrode 121 (platinum plating) are affected. (Predetermined characteristics cannot be obtained). On the other hand, in the burn-out process of the second embodiment, the plating resist film 110 is burned out at a temperature of 700 ° C. or lower (specifically, about 500 ° C.). In other words, in the plating resist film forming step, the plating resist film 110 (the plating resist film 110 having a burning temperature of 700 ° C. or lower) that is burned out at a temperature of 700 ° C. or lower (specifically, about 500 ° C.) is formed. For this reason, there is no possibility that the above problems (influencing the characteristics of the electrode 121 in the burning process) may occur.

  The gas sensor element 120 manufactured as described above can be used for manufacturing a gas sensor in the same manner as a conventional gas sensor element. In Example 2, the gas sensor 130 was manufactured in the same manner as Example 1 using the gas sensor element 120. FIG. 17 shows an example of a gas sensor 130 using the gas sensor element 120 manufactured by the manufacturing method of the present invention. The gas sensor 130 differs from the gas sensor of the first embodiment only in the gas sensor element, and the other parts are the same.

  In the above, the present invention has been described with reference to the first and second embodiments. However, the present invention is not limited to the above-described embodiments, and it can be applied as appropriate without departing from the scope of the present invention. Nor.

  Specifically, the gas sensor can be manufactured in the same manner as a conventional gas sensor, except that the gas sensor element obtained by the gas sensor element manufacturing method of the present invention is used. According to such a gas sensor manufacturing method of the present invention, since a gas sensor element that uses a small amount of noble metal is used, a gas sensor can be manufactured at a lower cost than a conventional gas sensor manufacturing method.

  In Example 1, a mask jig mounting step was performed after the nucleation step and before the plating step. However, the mask jig mounting step may be performed before the nucleation step. That is, the nucleation step and the plating step may be performed after the mask jig 18 is mounted on the mask portion 4 on the inner surface 1n of the substrate 1.

  In Example 2, a mask jig mounting step and a plating resist film forming step were performed after the nucleation step and before the plating step. However, the mask jig mounting step and the plating resist film forming step may be performed before the nucleation step. That is, the nucleation process and the plating process may be performed after the mask jig 18 is mounted on the mask part 104 of the inner surface 101n of the base 101 and the plating resist film 110 is formed on the plating resist part 105. .

DESCRIPTION OF SYMBOLS 1,101 Base | substrate 1m, 101m Tubular part 1n, 101n Base | substrate inner surface 3,103 Planned electrode part 3g, 103g Planned detection part 3s, 103s Planned lead part 3t, 103t Planned terminal connection part 4,104 Mask part 105 Plating resist Part 110 Plating resist film 12 Plating solution 18 Mask jig 18b Mask outer surface 20, 120 Gas sensor element 21, 121 Electrode 21g, 121g Detection part 21s, 121s Lead part 21t, 121t Terminal connection part 30, 130 Gas sensor L1 Arc of outer surface of mask Length L2 Peripheral length R1b of cylindrical portion Curvature radius R2 of mask outer surface before mask jig is mounted on mask portion Curvature radius of mask portion

Claims (5)

A nucleation step of attaching nuclei to the inner surface of a bottomed cylindrical base extending in the axial direction;
Using a plating solution in which the nucleus acts as a catalyst, a plating step for precipitating a noble metal in the plating solution on the inner surface of the substrate, and
A gas sensor element manufacturing method for forming an electrode made of the noble metal on the inner surface of the substrate,
Prior to the plating step, a mask jig mounting step of mounting a mask jig on a mask portion different from the electrode planned portion on which the electrode is to be formed on the inner surface of the base body,
After the mask jig mounting step, a liquid injection device is inserted into the substrate, and the plating solution is injected into the substrate using the liquid injection device, so that the noble metal is deposited on the planned electrode portion. The plating step,
The mask jig is
In the form extending in the axial direction,
When the mask jig is mounted on the mask part, the mask outer surface that comes into contact with the mask part forms an arc in a cross section obtained by cutting the mask jig in a direction perpendicular to the axial direction,
It is possible to elastically deform in the direction in which the radius of curvature of the mask outer surface expands and contracts
The curvature radius of the mask outer surface before mounting the mask jig on the mask portion is made larger than the curvature radius of the mask portion,
In the mask jig mounting process,
The mask jig is inserted into the base while elastically deforming the mask jig in a direction in which the radius of curvature of the mask outer surface decreases, and the mask outer surface is masked by the elastic restoring force of the mask jig. A method for manufacturing a gas sensor element, wherein the mask jig is fixed to the mask portion while being in close contact with the portion. It is a manufacturing method of the gas sensor element according to claim 1,
The length of the circular arc on the outer surface of the mask is longer than ½ of the circumferential length of the cylindrical portion including the mask portion in the circumferential direction on the inner surface of the base, and is not more than the circumferential length of the cylindrical portion. Device manufacturing method. It is a manufacturing method of the gas sensor element according to any one of claims 1 and 2,
Prior to the plating step, a plating resist film forming step of forming a plating resist film on the plating resist portion excluding the electrode portion and the mask portion of the inner surface of the substrate;
A method of manufacturing a gas sensor element, comprising: a burn-out step of burning off the plating resist film after the plating step. It is a manufacturing method of the gas sensor element according to claim 3,
In the plating resist film forming step, a method of manufacturing a gas sensor element, wherein a plating resist film made of an organic material not containing a metal component is formed as the plating resist film. A gas sensor manufacturing method comprising a gas sensor element and a metal shell for holding the gas sensor element ,
To produce the gas sensor element by the manufacturing method of the gas sensor element according to any one of 請 Motomeko 1 to claim 4, thereafter, comprises a step of holding the gas sensor element inside said metal shell <br / > Manufacturing method of gas sensor.

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