JP5018738B2 - Method for manufacturing gas sensor element - Google Patents

Description

The present invention relates to a method for manufacturing a glass Susensa element for detecting a specific gas concentration in the measurement gas.

  Conventionally, an oxygen ion conductive solid electrolyte body, a measurement electrode and a reference electrode provided on one surface and the other surface of the solid electrolyte body, and a surface of the solid electrolyte body on which the measurement electrode is disposed. A diffusion resistance layer that is laminated and forms a measurement gas chamber for introducing the measurement gas inside, and a dense shield that covers a surface of the diffusion resistance layer opposite to the surface on which the solid electrolyte body is disposed A gas sensor element formed by laminating layers is known (see, for example, Patent Document 1).

In the diffusion resistance layer, two contour lines constituting the outer surface of the diffusion resistance layer in an orthogonal cross section that is a cross section orthogonal to the axial direction of the gas sensor element proceed in a direction from the reference electrode toward the measurement electrode. As it gets closer to each other, it is ground.
In forming such a gas sensor element, it is ground from the corner of the shielding layer, and the diffusion resistance layer is ground into a tapered shape as described above.

JP 2005-249482 A

However, this conventional method for manufacturing a gas sensor element has the following problems. That is, the output current before grinding of the gas sensor elements included in the lot to be ground from now on may vary in the first place. In such a case, even if the same amount of grinding is performed, depending on the gas sensor element, the output current after grinding may be significantly different from the target output current.
Therefore, a method for manufacturing a gas sensor element having a desired output current and little product variation has been demanded.

The present invention has been made in view of such conventional problems, and a method for manufacturing a gas sensor element capable of producing a gas sensor element having a desired output current and less product variation by a simple method. It is intended to provide a law .

The present invention includes an oxygen ion conductive solid electrolyte body, a measurement electrode and a reference electrode provided on one surface and the other surface of the solid electrolyte body, and a surface on which the measurement electrode is disposed in the solid electrolyte body. A diffusion resistance layer that forms a measurement gas chamber into which the measurement gas is introduced, and a dense surface that covers a surface of the diffusion resistance layer opposite to the surface on which the solid electrolyte body is disposed. A method of manufacturing a gas sensor element formed by laminating a shielding layer,
The two contour lines constituting the outer surface of the diffusion resistance layer in an orthogonal cross section that is a cross section orthogonal to the axial direction of the gas sensor element are arranged so as to approach each other as they proceed in a direction from the reference electrode toward the measurement electrode. In grinding the diffusion resistance layer,
A reference output current A1 which is an output current when the reference diffusion distance, which is the shortest distance between the outer surface of the diffusion resistance layer and the gas chamber to be measured, is L1, in a state before grinding the diffusion resistance layer; A reference measuring step for measuring the reference diffusion distance L1;
After grinding the diffusion resistance layer, a post-grinding diffusion distance which is a value obtained by subtracting the grinding amount from the reference diffusion distance L1 and which is the shortest distance between the midpoint of the contour line and the gas chamber to be measured. A post-grinding measurement step that repeats the process of measuring the post-grinding output current A2 that is the output current when L2 and the post-grinding diffusion distance L2 multiple times
The difference between the post-grinding IL change rate y, which is the square root of the ratio of the reference output current A1 to the difference between the post-grinding output current A2 and the reference output current A1, and the difference between the reference diffusion distance L1 and the post-grinding diffusion distance L2. Using the diffusion distance change rate x, which is the ratio of the post-grinding diffusion distance L2 with respect to, the linear expression expressed by the following formula 1 that approximates the relationship between the post-grinding IL change rate y and the diffusion distance change rate x A constant calculating step for calculating a slope a and an intercept b in the function;
In the reference diffusion distance L1, the target IL change rate z that is the square root of the ratio of the reference output current A1 to the difference between the target output current that is the target output current and the reference output current A1, and the constant calculation step A calculated grinding amount calculating step of substituting the calculated slope a and the intercept b into the following formula 2 to calculate a target grinding amount M that is a grinding amount of the diffusion resistance layer for obtaining a desired output current;
A gas sensor element manufacturing method comprising: a grinding step of grinding the diffusion resistance layer by the target grinding amount M (Claim 1).
y = ax + b (Formula 1)
M = L1 × (1−a / (z−b + a)) (Formula 2)

The function and effect of the present invention will be described.
In the present invention, the target grinding amount M which is the grinding amount of the diffusion resistance layer for obtaining a predetermined output current using the reference diffusion distance L1, the target IL change rate z, the slope a and the intercept b. Is calculated. Then, the diffusion resistance layer is ground using the target grinding amount M obtained thereby. For this reason, according to the present invention, it is possible to provide a gas sensor element having a desired output current and less product variation by a simple method.

  That is, conventionally, when the reference output current A1 at the reference diffusion distance L1 varies, even if the diffusion resistance layer is ground by the same amount, depending on the gas sensor element, the target output current is greatly deviated. There was a case.

  In contrast, the inventor of the present application uses a quadratic curve in which the output current change rate, which is the ratio of the reference output current A1 to the difference between the post-grinding output current A2 and the reference output current A1, is the diffusion distance change rate x as a variable. We found that it can be approximated by Further, as a result of earnest research, the inventor of the present application converts the quadratic curve into a linear function by calculating the square root of this output current change rate, that is, the post-grinding IL change rate, and calculates its slope and intercept. Thus, it has been found that the target grinding amount M in the diffusion resistance layer of the gas sensor element to be ground can be easily estimated.

  If this is applied to a method for manufacturing a gas sensor element, even if there is some variation in the reference output current A1 before grinding in the lot to which the gas sensor element to be grounded belongs, it will be close to the target output current after grinding. be able to. That is, by estimating the target grinding amount M in advance and grinding the diffusion resistance layer by that amount, it is possible to easily produce a gas sensor element having a desired output current and less product variation.

In addition, by automating the manufacturing method of the gas sensor element of the present invention by approximating the relationship between the post-grinding IL change rate y and the diffusion distance change rate x by a linear function, a simple program can be used. The target grinding amount M can be easily calculated. Therefore, according to the present invention, it is possible to easily cope with a change in a program related to automation even if a lot changes.
As a result, a gas sensor element having excellent output accuracy as described above can be obtained by a simple method.

  As described above, according to the present invention, it is possible to provide a gas sensor element that can easily produce a gas sensor element having a desired output current and little product variation by a simple method.

As a reference the first aspect, there is Ruga Susensa device manufactured by the manufacturing method of the gas sensor element.
In this case, as described in the present invention, having a desired output current, Ru can provide less gas sensor element of the product variations.

For reference invention 2, detects the specific gas concentration in the measurement gas, Ruga Susensa be built gas sensor element according to the Reference Invention 1 Ru Oh.
If this is as described in Reference invention 1, having a desired output current, Ru can provide gas sensor less product variation.

  In the present specification, the gas sensor element is an air-fuel ratio sensor element that is installed in an exhaust pipe of an internal combustion engine for various vehicles such as an automobile engine and is used in an exhaust gas feedback system. There are oxygen sensor elements that measure the oxygen concentration, NOx sensor elements that check the concentration of atmospheric pollutants such as NOx that are used for detecting deterioration of the three-way catalyst installed in the exhaust pipe, and the like.

In addition, the gas sensor element obtained by performing at least the reference measurement step, the post-grinding measurement step, the constant calculation step, and the grinding amount calculation step prior to the workpiece that is the gas sensor element to be ground from now on. It is preferable to perform the grinding step on the workpiece using the target grinding amount M (Claim 2).
In this case, the workpiece can be ground by a target grinding amount M based on data calculated in advance. Therefore, a gas sensor element with little variation in output current can be easily obtained.

In addition, the reference measurement step, the post-grinding measurement step, the constant calculation step, the grinding amount calculation step, and the grinding step can be performed on a workpiece that is a gas sensor element to be ground. Item 3).
In this case, the workpiece can be ground by a target grinding amount M based on the data of the workpiece itself. Therefore, the deviation of the output current of the gas sensor element can be reliably prevented. As a result, a gas sensor element with little variation in output current can be easily manufactured.

Further, the present invention may be applied when manufacturing a gas sensor element in which a target grinding distance L3, which is a value obtained by subtracting the target grinding amount M from the reference diffusion distance L1, is 20 to 50% of the value of the reference diffusion distance L1. Preferred (claim 4).
In this case, the effect of the present invention can be remarkably exhibited.
That is, in a gas sensor element in which the output current changes greatly with a small amount of grinding, it is necessary to calculate the target grinding amount M with sufficient precision. Therefore, by applying the present invention to the gas sensor element having a large grinding amount as described above, the function and effect of the present invention can be remarkably exhibited.

For example of a method of manufacturing a gas sensor element according to the present invention will be described in conjunction with FIGS.
As shown in FIG. 1, the gas sensor element 2 of the present example includes an oxygen ion conductive solid electrolyte body 21, a measurement electrode 22 and a reference electrode 23 provided on one surface and the other surface of the solid electrolyte body 21. Have
Examples will be described with reference to FIGS.
As shown in FIG. 1, the gas sensor element 2 of the present example includes an oxygen ion conductive solid electrolyte body 21, a measurement electrode 22 and a reference electrode 23 provided on one surface and the other surface of the solid electrolyte body 21. Have

Further, the gas sensor element 2 is laminated on the surface of the solid electrolyte body 21 on which the measurement electrode 22 is disposed, and a diffusion resistance layer 24 that forms a measurement gas chamber 240 into which a measurement gas is introduced, and a diffusion resistance. The layer 24 has a dense shielding layer 25 that covers the surface opposite to the surface on which the solid electrolyte body 21 is disposed.
And these are laminated | stacked as shown in FIG. 1, and the gas sensor element 2 is formed.
Details will be described below.

First, the gas sensor 1 of the present example including the gas sensor element 2 will be described with reference to FIG.
In addition to the gas sensor element 2, the gas sensor 1 includes a housing 11, an element cover 12, an atmosphere side cover 13, an element side insulator 14, an atmosphere side insulator 15, and a bush 16 as shown in FIG. And a lead wire 17.

The housing 11 is made of, for example, metal, and inserts and holds an element side insulator 14 to be described later inside thereof.
The element cover 12 is fixed to the distal end side of the housing 11 and protects the distal end side of the gas sensor element 2. In this example, the element cover 12 has a double structure, and both the outer cover 121 and the inner cover 122 have gas introduction holes 123 for introducing the gas to be measured on the bottom surface and side surfaces thereof.

The atmosphere side cover 13 is fixed to the proximal end side of the housing 11. At the base end of the atmosphere side cover 13 itself, an atmosphere introduction hole 130 for introducing the atmosphere is formed.
The element side insulator 14 is formed in a cylindrical shape, and the gas sensor element 2 is inserted and held inside thereof.

The atmosphere-side insulator 15 is inside the atmosphere-side cover 13 and holds the base end side of the gas sensor element 2 with a metal terminal 18 electrically connected to a lead wire 17 described later. .
The bush 16 is disposed at the base end portion of the atmosphere-side cover 13 and holds a lead wire 17 for electrically connecting an external power source and the gas sensor element 2.

Next, the gas sensor element 2 of this example will be described with reference to FIG.
The gas sensor element 2 is installed in an exhaust pipe of an internal combustion engine for various vehicles such as an automobile engine, and is an air-fuel ratio sensor element built in an air-fuel ratio sensor used in an exhaust gas feedback system, and measures the oxygen concentration in the exhaust gas. There are oxygen sensor elements, NOx sensor elements for examining the concentration of air pollutants such as NOx used for detecting deterioration of a three-way catalyst installed in an exhaust pipe, and the like.

  Further, as described above, the gas sensor element 2 includes the solid electrolyte body 21, the measurement electrode 22, the reference electrode 23, the gas chamber to be measured 240, the diffusion resistance layer 24, and the shielding layer 25. It has a component.

That is, the gas sensor element 2 is formed by being surrounded by the reference gas chamber forming layer 26, the reference gas chamber forming layer 26, and the solid electrolyte body 21 stacked on the surface of the solid electrolyte body 21 on which the measurement electrode 22 is disposed. A reference gas chamber 260 and a heater 27 for heating the gas sensor element 2.
The heater 27 includes a heat generating portion 272 that generates heat when energized, and a ceramic heater substrate 271 that holds the heat generating portion 272.

  As shown in FIG. 1, the gas sensor element 2 of the present example has, for example, a height h of 1.39 to 1.41 mm and a width w in an orthogonal cross section that is a cross section orthogonal to the axial direction of the gas sensor element 2. Is a small size of 3.08 to 3.48 mm.

Next, the manufacturing method of the gas sensor element 2 of this example is demonstrated in detail with FIG. 3, FIG.
In the manufacturing method of this example, as shown in FIG. 4, the two contour lines n constituting the outer surface 241 of the diffusion resistance layer 24 in the orthogonal cross section proceed in the direction from the reference electrode 23 toward the measurement electrode 22. The diffusion resistance layer 24 is ground so as to approach each other.

In the manufacturing method of this example, a reference measurement step (step S1), a post-grinding measurement step (step S2), a constant calculation step (step S3), a grinding amount calculation step (step S4), which will be described later, A grinding step (step S5).
Hereinafter, each process is demonstrated concretely.

In the following description, after performing the reference measurement process (step S1) on the entire lot to which the workpiece, which is the gas sensor element 2 to be ground, belongs, after grinding to any gas sensor element 2 included in the lot Using the data obtained through the measurement process (step S2), the constant calculation process (step S3), the grinding amount calculation process (step S4), and the grinding process (step S5), On the other hand, what performs a grinding process (step S5) is introduced.
Further, in the gas sensor element 2 of this example, a target diffusion distance L3 that is a value obtained by subtracting a target grinding amount M from a reference diffusion distance L1 described later is 20 to 50% of the value of the reference diffusion distance L1.

(Standard measurement process)
First, in the reference measurement step (step S1), the reference diffusion distance which is the shortest distance between the outer surface 241 of the diffusion resistance layer 24 and the gas chamber 240 to be measured in the state before grinding the diffusion resistance layer 24 is set to L1. Output the reference output current A1 and the reference diffusion distance L1.
In this example, the reference diffusion distance L1 is, for example, 980 to 1140 μm.

  In this example, the reference diffusion distance L1 is constant for all gas sensor elements 2 in all lots. Therefore, in the reference measurement process (step 1) of this example, it is only necessary to measure only the reference output current A1 of all the gas sensor elements 2 included in the lot to be ground.

Further, at the stage of the reference measurement process (step S1), four samples to be used in the post-grinding measurement process (step S2) described later are selected.
As the four samples, the gas sensor elements 2 that are measured in the reference measurement step (step S1) and that serve as the upper limit value, lower limit value, average value, etc. of the reference output current A1 of the gas sensor elements 2 included in the lot are selected. It is preferable.

  The reference diffusion distance L1 can be measured every time the data of any gas sensor element 2 included in the lot to which the workpiece belongs belongs every time the lot changes. In this case, even if the reference diffusion distance L1 changes depending on the lot, it is not affected by it. And the trend of the lot to which the gas sensor element 2 belongs can be reflected better.

(Measurement process after grinding)
Next, in the post-grinding measurement step (step S2), after grinding the diffusion resistance layer 24 of four samples selected from the lot to which the workpiece belongs, the midpoint M of the contour line n in the orthogonal cross section and the measurement target are measured. The process of measuring the post-grinding output current A2 and the post-grinding diffusion distance L2, which are output currents when the post-grinding diffusion distance that is the shortest distance to the gas chamber 240 is L2, is repeated a plurality of times.

  That is, in order to calculate the post-grinding IL change rate y, which will be described later, more accurately, the post-grinding output current A2 and the post-grinding diffusion distance L2 are measured twice or more, that is, using two or more gas sensor elements 2, respectively. A2 and L2 need to be measured. In this example, the post-grinding IL change rate y was calculated as 4 points, one each from each of the gas sensor elements 2 which are four samples included in the lot to which the workpiece belongs, as described above.

Specifically, target grinding is performed in accordance with a grinding amount calculation step (step S4) described later using data in a lot ground before the lot to which the workpiece belongs as an inclination a and an intercept b in a linear function described later. The amount M is calculated.
Next, the diffusion resistance layers 24 of the four samples are ground by the target grinding amount M.
Then, after grinding the four samples, the post-grinding output current A2 and the post-grinding diffusion distance L2 are measured.

  In the post-grinding measurement step (step S2), unlike the above, the post-grinding diffusion distance L2 calculated by grinding the diffusion resistance layer 24 of the workpiece to be ground and the post-grinding output. The slope a and the intercept b can also be calculated using the current A2. In this case, as the reference diffusion distance L1 of itself, a value measured in advance by another gas sensor element 2 may be used as a constant.

(Constant calculation process)
Next, in the constant calculation step (step S3), the post-grinding IL change rate y that is the square root of the ratio of the reference output current A1 to the difference between the post-grinding output current A2 and the reference output current A1, the reference diffusion distance L1, and the grinding. Using the diffusion distance change rate x that is the ratio of the post-grinding diffusion distance L2 to the difference from the post-diffusion distance L2, the following equation is used to approximate the relationship between the post-grinding IL change rate y and the post-grinding diffusion distance change rate x A slope a and an intercept b in the linear function represented by 1 are calculated.
y = ax + b (Formula 1)

  Specifically, as described above, diffusion in the above four samples is performed by the target grinding amount M calculated using the after-grind diffusion distance L2 and the after-grind output current A2 of the lot ground before the lot to be ground. The resistance layer 24 is ground. Then, using the post-grind diffusion distance L2 and post-grind output current A2 further obtained from the data obtained from the four samples that have been ground, the procedure for obtaining the slope a and the intercept b is performed again. The slope a and the intercept b at this time are constants for grinding a lot to be ground.

(Grinding amount calculation process)
Next, in the grinding amount calculation step (step S4), the target IL that is the square root of the ratio of the reference output current A1 to the reference diffusion distance L1 and the difference between the target output current that is the target output current and the reference output current A1. The change rate z and the slope a and the intercept b recalculated by the values obtained from the four samples of the lot to be ground in the constant calculation step (step S3) are substituted into the following formula 2, and grinding is performed from now on. The target grinding amount M which is the grinding amount of the diffusion resistance layer 24 for obtaining the desired output current of the lot to be obtained is recalculated.
M = L1 × (1−a / (z−b + a)) (Formula 2)
In this example, the target grinding amount M is, for example, 200 to 600 μm.

(Grinding process)
Next, in the grinding process, the diffusion resistance layer 24 in the workpiece is ground by the target grinding amount M recalculated as described above.
Actually, since the gas sensor element 2 of this example is provided with the shielding layer 25, the diffusion resistance layer 24 is also ground with respect to the grinding amount of the shielding layer 25 (see the symbol Ls in FIG. 4C). In doing so, it is necessary to consider.

  By the above procedure, the gas sensor element 2 having the diffusion resistance layer 24 ground by the target grinding amount M from the reference diffusion distance L1 can be obtained.

  In this example, the grinding angle (refer to the symbol θ in FIG. 4C), which is the angle between the main surface of the diffusion resistance layer 24 and the outer side surface 241 after grinding, is 45 °. The angle θ is not limited to this. That is, the grinding angle θ can be set to 40 to 60 °, for example. And in the manufacturing method of the gas sensor element 2 of this example, by setting it as the above grinding angles (theta), the reduction | decrease of the cross-sectional area of the duct part in the gas sensor element 2 is suppressed to the minimum, and the gas sensor element 2 with respect to element bending The strength of the can be ensured. Further, it is possible to obtain an advantage that the reduction of the area of the shielding layer 25 covering the diffusion resistance layer 24 can be minimized.

  Moreover, even if the thickness and porosity of the diffusion resistance layer 24 are variously changed, the present invention can be sufficiently applied. Even in this case, the effects of the present invention can be sufficiently exhibited.

Below, the effect of this example is demonstrated.
In this example, the target grinding amount M, which is the grinding amount of the diffusion resistance layer 24 for obtaining a predetermined output current, is calculated using the reference diffusion distance L1, the target IL change rate z, the slope a, and the intercept b. . Then, the diffusion resistance layer is ground 24 using the target grinding amount M obtained thereby. For this reason, according to this example, it is possible to provide the gas sensor element 2 having a desired output current and less product variation by a simple method.

  That is, conventionally, when the reference output current A1 at the reference diffusion distance L1 varies, even if the diffusion resistance layer 24 is ground by the same amount, depending on the gas sensor element, the target output current largely deviates. There was a case.

  In contrast, the inventor of the present application uses a quadratic curve in which the output current change rate, which is the ratio of the reference output current A1 to the difference between the post-grinding output current A2 and the reference output current A1, is the diffusion distance change rate x as a variable. We found that it can be approximated by Furthermore, as a result of earnest research, the inventor of the present application converts the quadratic curve into a linear function by calculating the square root of the output current change rate, that is, the IL change rate after grinding, and calculates the slope a and intercept b. It has been found that the target grinding amount M in the diffusion resistance layer 24 of the gas sensor element 2 to be ground can be easily estimated by calculating (see FIG. 5).

  If this is applied to the manufacturing method of the gas sensor element 2, even if there is some variation in the reference output current A1 before grinding in the lot to which the gas sensor element 2 to be grounded belongs, the target output current after grinding Can be approached. That is, by preliminarily estimating the target grinding amount M and grinding the diffusion resistance layer 24 by that amount, the gas sensor element 2 having a desired output current and less product variation can be easily manufactured.

Moreover, by automating the manufacturing method of the gas sensor element 2 of this example by approximating the relationship between the IL change rate y after grinding and the diffusion distance change rate x by a linear function in this way, a simple program is used. The target grinding amount M can be easily calculated. Therefore, according to the present invention, it is possible to easily cope with a change in a program related to automation even if a lot changes.
As a result, the gas sensor element 2 having excellent output accuracy as described above can be obtained by a simple method.

  In this example, the reference measurement step (step S1), the post-grinding measurement step (step S2), the constant calculation step (step S3), and the grinding amount are preceded by the workpiece which is the gas sensor element to be ground. The grinding step is performed on the workpiece using the target grinding amount M obtained by the gas sensor element 2 that has performed the calculation step (step S4). Therefore, the workpiece can be ground by a target grinding amount M based on data calculated in advance. Therefore, the gas sensor element 2 with little variation in output current can be easily obtained.

Moreover, the manufacturing method of this example manufactures the gas sensor element 2 in which the value of the target diffusion distance L3, which is a value obtained by subtracting the target grinding amount M from the reference diffusion distance L1, is 20 to 50% of the value of the reference diffusion distance L1. Since it is applied to the case, the effect of the present invention can be remarkably exhibited.
That is, in the gas sensor element 2 in which the output current changes greatly with a small amount of grinding as described above, it is necessary to calculate the target grinding amount M with sufficient precision. Thus, by applying the present invention to the gas sensor element 2 as described above, the effects of the present invention can be remarkably exhibited.

  In addition, the gas sensor 1 of the present example detects the specific gas concentration in the gas to be measured and incorporates the gas sensor element 2 so that a desired output current can be obtained and the gas sensor 1 with less product variation can be obtained. Can do.

  As described above, according to this example, a gas sensor element that can produce a gas sensor element having a desired output current and little product variation by a simple method, a gas sensor incorporating the gas sensor element, and a gas sensor An element manufacturing method can be provided.

2 is a cross-sectional view of a gas sensor element having an orthogonal cross section in Embodiment 1. FIG. 1 is a longitudinal sectional view of a gas sensor in Embodiment 1. FIG. 2 is a flowchart for a method for manufacturing a gas sensor element in the first embodiment. In Example 1, (a) explanatory diagram showing a state before grinding the diffusion resistance layer, (b) explanatory diagram showing a state in which the diffusion resistance layer is ground, (c) after grinding the diffusion resistance layer Explanatory drawing which shows a state. In Example 1, (a) plot diagram showing the relationship between the ratio of the reference output current to the difference between the output current after grinding and the reference output current and the grinding amount, (b) the output current after grinding and the reference output current The plot figure which shows the relationship with the IL change rate after grinding which is a square root of ratio of the reference output current with respect to a difference.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas sensor 2 Gas sensor element 21 Solid electrolyte body 22 Measuring electrode 23 Reference electrode 24 Diffusion resistance layer 240 Gas chamber to be measured 241 Outer side surface 25 Shielding layer A1 Reference output current A2 Output current after grinding a Inclination b Section L1 Reference diffusion distance L2 After grinding Diffusion distance M Target grinding amount x Diffusion distance change rate y Post-grinding IL change rate z Target IL change rate

Claims (4)

An oxygen ion conductive solid electrolyte body, a measurement electrode and a reference electrode provided on one surface and the other surface of the solid electrolyte body, and a surface of the solid electrolyte body on which the measurement electrode is disposed are stacked. And a diffusion resistance layer that forms a measurement gas chamber into which the measurement gas is introduced, and a dense shielding layer that covers a surface of the diffusion resistance layer opposite to the surface on which the solid electrolyte body is disposed. A method of manufacturing a gas sensor element formed by stacking,
The two contour lines constituting the outer surface of the diffusion resistance layer in an orthogonal cross section that is a cross section orthogonal to the axial direction of the gas sensor element are moved closer to each other as they proceed in a direction from the reference electrode toward the measurement electrode. In grinding the diffusion resistance layer,
A reference output current A1 which is an output current when the reference diffusion distance, which is the shortest distance between the outer surface of the diffusion resistance layer and the gas chamber to be measured, is L1, in a state before grinding the diffusion resistance layer; A reference measuring step for measuring the reference diffusion distance L1;
After grinding the diffusion resistance layer, a post-grinding diffusion distance which is a value obtained by subtracting the grinding amount from the reference diffusion distance L1 and which is the shortest distance between the midpoint of the contour line and the gas chamber to be measured. A post-grinding measurement step that repeats the process of measuring the post-grinding output current A2 that is the output current when L2 and the post-grinding diffusion distance L2 multiple times
The difference between the post-grinding IL change rate y, which is the square root of the ratio of the reference output current A1 to the difference between the post-grinding output current A2 and the reference output current A1, and the difference between the reference diffusion distance L1 and the post-grinding diffusion distance L2. Using the diffusion distance change rate x, which is the ratio of the post-grinding diffusion distance L2 with respect to, the linear expression expressed by the following formula 1 that approximates the relationship between the post-grinding IL change rate y and the diffusion distance change rate x A constant calculating step for calculating a slope a and an intercept b in the function;
In the reference diffusion distance L1, the target IL change rate z that is the square root of the ratio of the reference output current A1 to the difference between the target output current that is the target output current and the reference output current A1, and the constant calculation step A calculated grinding amount calculating step of substituting the calculated slope a and the intercept b into the following formula 2 to calculate a target grinding amount M that is a grinding amount of the diffusion resistance layer for obtaining a desired output current;
And a grinding step of grinding the diffusion resistance layer by the target grinding amount M.
y = ax + b (Formula 1)
M = L1 × (1−a / (z−b + a)) (Formula 2)   The gas sensor element according to claim 1, wherein at least the reference measurement step, the post-grinding measurement step, the constant calculation step, and the grinding amount calculation step are performed prior to a workpiece that is a gas sensor element to be ground. A method for producing a gas sensor element, wherein the grinding step is performed on the workpiece using the target grinding amount M obtained.   In Claim 1, performing the said reference | standard measurement process, the said post-grinding measurement process, the said constant calculation process, the said grinding amount calculation process, and the said grinding process with respect to the workpiece which is a gas sensor element which is going to grind from now on A method for manufacturing a gas sensor element.   The gas sensor according to any one of claims 1 to 3, wherein a target diffusion distance L3, which is a value obtained by subtracting the target grinding amount M from the reference diffusion distance L1, is 20 to 50% of the value of the reference diffusion distance L1. A method for manufacturing a gas sensor element, which is applied to manufacturing an element.

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