JP4572486B2 - Gas sensor element and manufacturing method thereof - Google Patents

Description

[0001]
【Technical field】
The present invention relates to various gas sensor elements that are attached to an exhaust system of an internal combustion engine and used for combustion control, and a method for manufacturing the same.
[0002]
[Prior art]
An exhaust system of an automobile engine is provided with a gas sensor for use in combustion control. As a gas sensor element incorporated therein, an element having a configuration as disclosed in Japanese Patent Laid-Open No. 9-26409 is known.
[0003]
As shown in FIG. 16, this gas sensor element 9 has a reference gas chamber made of an alumina substrate with respect to a solid electrolyte plate 93 having a measured gas side electrode 11 in contact with the measured gas and a reference gas side electrode 12 in contact with the reference gas. It is formed by laminating spacer plates 94 configured together with 95. As shown in the figure, the spacer plate 94 is U-shaped and has a window portion 940 for forming a reference gas chamber.
[0004]
The reference gas chamber of the gas sensor element 9 is configured as an open end whose one end is a closed end and the other end is opened to the outside of the gas sensor element, so that the atmosphere or the like serving as a reference gas is introduced from the open end. Has been.
Although not shown, a heater substrate having a heating element is laminated on the alumina substrate 95.
[0005]
[Problems to be solved]
By the way, since the gas sensor element 9 is hollow, its mechanical strength is weak, and damage due to impact is likely to occur when the gas sensor element 9 is manufactured or assembled to the gas sensor.
Further, when used in an exhaust system of an internal combustion engine, it may be damaged by thermal stress due to a temperature difference before and after the internal combustion engine is started.
[0006]
Further, in the gas sensor element 9 having the above-described conventional configuration, the spacer plate 94 and the alumina substrate 95 may be defective or troubled due to separation during the manufacturing process or use of the gas sensor element.
[0007]
Furthermore, in recent years, there has been a growing demand for gas sensor elements that are faster in response and faster in activity than ever before, and the conventional gas sensor elements have been desired to be further improved in both performances.
[0008]
The present invention has been made in view of such conventional problems, and is a gas sensor element that is less likely to be damaged or defective due to mechanical stress or thermal stress, has excellent durability, responsiveness, and early activation, and a method for manufacturing the same. Is to provide.
[0009]
[Means for solving problems]
The invention according to claim 1 comprises a solid electrolyte plate comprising a measured gas side electrode in contact with the measured gas and a reference gas side electrode in contact with the reference gas;
A reference gas chamber facing the reference gas side electrode, having one end as a closed end and the other end as an open end opened to the outside of the gas sensor element, and configured to introduce a reference gas A spacer plate with
A gas sensor element in which a heater substrate having a heating element that generates heat when energized is laminated,
The corner portion at the closed end of the reference gas chamber is formed by a curved surface in the width direction .
Further, in the cut surface along the plane parallel to the longitudinal direction passing through the center in the width direction of the reference gas chamber and perpendicular to the width direction, the corner in the longitudinal direction at the closed end is constituted by a curved surface and The gas sensor element is characterized in that the radius of curvature is 1 mm to 20 mm.
[0010]
The function and effect of the present invention will be described.
The gas sensor element according to the present invention is configured such that the corner portion in the longitudinal direction at the closed end of the groove-shaped reference gas chamber has a curved surface and a radius of curvature of 1 mm to 20 mm.
If the radius of curvature is less than 1 mm, the corners in the longitudinal direction are not sufficiently rounded, and it is difficult to obtain the effects of the present invention and it may be difficult to obtain excellent durability.
In addition, when the radius of curvature exceeds 20 mm, the amount of oxygen supplied and exhausted is low, and the detection limit on the rich side may be lowered particularly when the gas sensor element according to the present invention is used as an A / F sensor. is there.
[0011]
The reference gas chamber according to the present invention is constituted by a groove provided in the spacer plate. The corner is a terminal formed near the gas sensor element reference gas side electrode, that is, on the closed end side of the reference gas chamber (see FIG. 1 and the like).
[0012]
The width direction of the reference gas chamber and the longitudinal direction perpendicular to the width direction are specifically described in FIG. The longitudinal direction is approximately the central axis direction of the gas sensor element, and the width direction can be regarded as the radial direction of the gas sensor element.
[0013]
In the reference gas chamber of the gas sensor element according to the present invention, since the curved surface of the corner in the longitudinal direction has a radius of curvature in the above-described range, when thermal and mechanical stresses are generated, these stresses are concentrated on the corners. It becomes difficult to do.
Therefore, it is possible to obtain a gas sensor element that is not easily damaged by thermal stress and can withstand a cooling cycle in a wide temperature range.
For the same reason, it is difficult to cause damage due to mechanical stress, and a gas sensor element that is resistant to impact can be obtained.
[0014]
In the present invention, as described above, the width direction of the corner is also constituted by a curved surface.
In this way, in the present invention, since the corner is curved in both the width direction and the longitudinal direction, it is difficult for the reference gas to stagnate in the corner, and the responsiveness of the gas sensor element can be improved. .
Further, since the corner portion is curved in both the width direction and the longitudinal direction , as is apparent from FIG. 1 and the like, the heat transfer path from the heating element to the reference gas side electrode passes through the spacer plate longer. Therefore, the heat of the heating element is easily conducted to the reference gas side electrode.
For this reason, the time for raising the temperature of the gas sensor element to the element activation temperature can be shortened, and a gas sensor element excellent in early activation can be obtained.
[0015]
As described above, according to the present invention, it is possible to provide a gas sensor element that is hardly damaged or defective due to mechanical stress or thermal stress, has excellent durability, and has excellent responsiveness and early activation.
[0016]
In addition, when the reference gas chamber having a curved corner according to the present invention is formed by cutting, the processing of the reference gas chamber can be completed by cutting once.
If the reference gas chamber has a corner portion close to a right angle, it is necessary to repeat a plurality of times of cutting until a desired shape is obtained. That is, the reference gas chamber according to the present invention can be manufactured with a smaller number of steps.
In addition, when the reference gas chamber is manufactured by pressing, the corners are curved, so that the die removal process is facilitated.
That is, the gas sensor element according to the present invention is easy to manufacture.
[0017]
The gas sensor element is a so-called laminated type, and can be used as an air-fuel ratio sensor element installed in an exhaust system of an automobile engine in addition to being used as a normal oxygen sensor element. In addition, it can be used as a NOx sensor element, a composite sensor element, etc. by increasing the number of electrodes.
[0018]
Next, the invention according to claim 2 is a solid electrolyte plate comprising a measured gas side electrode in contact with the measured gas and a reference gas side electrode in contact with the reference gas;
A reference gas chamber facing the reference gas side electrode, having one end as a closed end and the other end as an open end opened to the outside of the gas sensor element, and configured to introduce a reference gas A spacer plate with
A heater substrate with a heating element that generates heat when energized is laminated,
The corner at the closed end of the reference gas chamber has a curved surface in the width direction ,
In addition, in the cut surface along the plane parallel to the longitudinal direction passing through the center in the width direction of the reference gas chamber and perpendicular to the width direction, the corner in the longitudinal direction at the closed end is formed by a curved surface. In manufacturing a gas sensor element having a curvature radius of 1 mm to 20 mm ,
Prepare a raw sheet for the solid electrolyte plate, a raw sheet for the spacer plate, and a raw sheet for the heater substrate,
A printing section for electrode formation is provided on the raw sheet for the solid electrolyte plate, and a printing section for the heating element is provided on the raw sheet for the heater substrate.
Groove processing is performed on the raw sheet for the spacer plate to form a groove portion having a closed end and an open end that serve as a reference gas chamber, and a corner portion of the closed end is formed by a curved surface.
A raw sheet for a spacer plate is laminated on a raw sheet for a heater substrate, and further, a raw sheet for a solid electrolyte plate is laminated on the raw sheet and bonded together with an adhesive to form an unfired laminate.
Then, it is in the manufacturing method of the gas sensor element characterized by baking an unbaked laminated body.
[0019]
In the manufacturing method according to the present invention, the spacer sheet raw sheet is provided with a groove for forming a reference gas chamber. An example of the reference gas chamber formed from the groove is shown in FIGS. 2, 3 , and 6 to be described later , but is formed in the raw sheet for the spacer plate as a recess that does not penetrate.
Unlike the conventional configuration shown in FIG. 16 described above, since the reference gas chamber is provided as a groove in the spacer raw sheet, various defects and troubles due to the separation of the spacer plate-alumina substrate that may occur in the conventional configuration can be eliminated. it can.
In addition, since each raw sheet is bonded with an adhesive, the sheets are strongly bonded to each other, and various defects and troubles due to peeling between other sheets are unlikely to occur.
[0020]
Further, as shown in FIG. 6, the corner portion of the reference gas chamber is curved in both the width direction and the longitudinal direction , so that thermal and mechanical stresses are unlikely to concentrate on the corner portion.
Therefore, it is possible to obtain a gas sensor element that is not easily damaged by thermal stress and can withstand a cooling cycle in a wide temperature range. Further, it is possible to manufacture a gas sensor element that is not easily damaged by mechanical stress and is resistant to impact.
[0021]
Further, since the corner portion is curved in both the width direction and the longitudinal direction, it is difficult for the reference gas to stagnate at the corner portion, and the responsiveness of the gas sensor element can be improved.
Moreover, amount that the corner portion becomes curved, but it is apparent from FIG. 1 and the like, the heat transfer path to the reference gas-side electrode from the heating element is to pass through the longer spacer plate. Therefore, the heat of the heating element is easily conducted to the reference gas side electrode.
For this reason, it is possible to shorten the time for raising the temperature of the gas sensor element to the element activation temperature, and it is possible to manufacture a gas sensor element excellent in early activation.
[0022]
As described above, according to the present invention, it is possible to provide a method for manufacturing a gas sensor element that is less likely to be damaged or defective due to mechanical stress or thermal stress, has excellent durability, responsiveness, and early activation.
[0023]
Each raw sheet can be made in a size that allows one gas sensor element to be taken, but from the viewpoint of manufacturing efficiency, each raw sheet is configured to a size that allows a plurality of gas sensor elements to be taken, It is preferable that a plurality of gas sensor elements are formed by stacking and then being separated into one gas sensor element by cutting or the like (refer to Embodiment 3 for details).
[0024]
Next, as in the invention described in claim 3, the groove processing is preferably performed by cutting.
Thereby, the groove pitch-groove shape can be processed with high accuracy.
[0025]
Next, as in a fourth aspect of the invention, the groove processing is preferably performed by press processing.
As a result, a large number of grooves can be formed at the same time by a single press process, so that the consumption of processing tools is reduced and the cost can be reduced.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
A gas sensor element according to a reference example will be described with reference to FIGS.
As shown in FIG. 1, the gas sensor element 1 of this example includes a solid electrolyte plate 13 having a measured gas side electrode 11 in contact with a measured gas and a reference gas side electrode 12 in contact with a reference gas, and the reference gas side electrode. 11, a spacer plate 14 having a reference gas chamber 10 configured to introduce a reference gas and a heater substrate 15 having a heating element 150 that generates heat when energized are laminated.
The reference gas chamber 10 has a groove shape in which one end provided with the reference gas side electrode 12 is a closed end 102 and the other end is an open end 101 opened to the outside of the gas sensor element 1.
[0027]
As shown in FIGS. 1 and 3, the corner portion 100 at the closed end 102 of the reference gas chamber 10 is formed of a curved surface in the longitudinal direction, and is a plane parallel to the axial direction passing through the center in the width direction of the reference gas chamber 10. In the cut axial sectional shape (see broken line C in FIG. 3), the radius of curvature of the corner 100 is in the range of 1 mm to 20 mm.
[0028]
This will be described in detail below.
The gas sensor element 1 of this example is built in a gas sensor 2 as shown in FIG. 4, is attached to an exhaust system of an automobile engine, and is used for engine combustion control.
As shown in FIGS. 1 to 3, the gas sensor element 1 of this example includes an oxygen ion conductive zirconia solid electrolyte plate 13, a spacer plate 14 made of an alumina insulator, an alumina heater substrate 15, and the like. Are stacked.
[0029]
A measured gas side electrode 11 and a reference gas side electrode 12 are provided for the solid electrolyte plate 13. The measured gas side electrode 11 is covered with an electrode protective layer 135.
Although not shown in the figure, the solid electrolyte plate 13 is provided with an output extraction terminal portion and a lead portion that are electrically connected to the measured gas side electrode 11 and the reference gas side electrode 12.
Further, the heater substrate 15 is provided with a lead portion 151 that is electrically connected to the heating element 150.
[0030]
The corner portion 100 in the longitudinal direction of the reference gas chamber 10 has a shape curved in the longitudinal direction of the gas sensor element 1, and the value measured along the broken line C in FIG. The radius of curvature of the gas sensor element 1 according to this example is 10 mm.
The broken line C is a cut surface along a plane passing through the center O in the width direction (see FIG. 3) of the gas sensor element 1 and parallel to the longitudinal direction of the gas sensor element 1 (see FIGS. 1 and 3).
[0031]
The gas sensor 2 incorporating the gas sensor element 1 according to this example will be described.
As shown in FIG. 4, the gas sensor 2 of this example includes a cylindrical housing 20, a double measured gas side cover 21 provided on the distal end side of the housing 20, and an air side cover provided on the proximal end side. 22. An outer cover 221 is provided on the base end side of the atmosphere side cover 22 via a water repellent filter 220.
The gas sensor element 1 inserted through the distal end side insulator 241 is inserted inside the housing 20, and the proximal end side insulator 242 is disposed inside the atmosphere side cover on the proximal end side of the gas sensor element 1. Yes.
[0032]
An output extraction terminal 231 of the gas sensor element 1 is disposed inside the proximal insulator 242, and this terminal 231 is connected to a lead wire 233 drawn out of the gas sensor 1 through a connection fitting 232. Further, an elastic insulating member 25 is provided inside the most proximal side of the atmosphere side cover 22, and a lead wire 233 is inserted therethrough.
[0033]
The effect concerning this example is demonstrated.
In the reference gas chamber 10 shown in this example, since the curved surface of the corner portion 100 has a radius of curvature in the above-described range, it is difficult to cause damage due to thermal stress, and the gas sensor element 1 that can withstand a cooling cycle in a wide temperature range is obtained. Can do. Further, it is possible to obtain a gas sensor element 1 that is not easily damaged by mechanical stress and is resistant to impact.
[0034]
Further, since the corners in the longitudinal direction are curved, it is difficult for stagnation of the reference gas at the corners 100.
That is, the reference gas entering from the opening end 101 moves along the shape of the reference gas chamber 10 and is smoothly guided to the reference gas side electrode 12 by the curved surface shape of the corner portion 100. For this reason, the gas sensor element 1 excellent in responsiveness can be obtained.
Furthermore, since the corner portion 100 has a curved surface, as is apparent from FIG. 1, the heat transfer path from the heating element 150 to the reference gas electrode 12 passes through the spacer plate 14 longer. Therefore, the heat of the heating element 150 can be easily conducted to the reference gas side electrode 12, and the gas sensor element 1 having excellent early activity can be obtained.
[0035]
As described above, according to this example, it is possible to provide a gas sensor element that is hardly damaged or defective due to mechanical stress or thermal stress, has excellent durability, and has excellent responsiveness and early activation.
[0036]
In addition, as an element having a configuration different from the gas sensor element described in this example, an element that can be used as an A / F sensor element by being installed in an exhaust system of an internal combustion engine can be used.
In this device, instead of the electrode protection layer 135 shown in FIG. 1, the measured gas side electrode 11 is covered with a diffusion resistance layer 136 and a shielding layer 137 as shown in FIG.
Also in this case, the same effect as in this example can be obtained by making the corner portion 100 of the reference gas chamber 10 into a curved surface as in this example.
[0037]
Embodiment 1
This example is a gas sensor element 1 having a configuration similar to that of the above reference example, and the reference gas chamber 100 has a curved shape not only in the longitudinal direction but also in the width direction of the gas sensor element 1.
As shown in FIGS. 5 and 6, the gas sensor element 1 of the present example includes a reference gas chamber 10 having a curved corner portion 100.
As is apparent from FIG. 6B, the corner portion 100 is curved not only in the longitudinal direction of the gas sensor element 1 but also in the width direction.
Others are the same as the reference example and have the same effects.
In this example, the corner is curved in both the width direction and the longitudinal direction. Therefore, it is difficult for the reference gas to stagnate at the corners, and the responsiveness of the gas sensor element can be improved.
Further, since the corners are curved in both the width direction and the longitudinal direction, the heat transfer path from the heating element to the reference gas side electrode is longer and passes through the spacer plate, as is apparent from FIGS. It will be. Therefore, the heat of the heating element is easily conducted to the reference gas side electrode.
For this reason, the time for raising the temperature of the gas sensor element to the element activation temperature can be shortened, and a gas sensor element excellent in early activation can be obtained.
[0038]
Embodiment 2
In this example, the manufacturing method of the gas sensor element 1 described in the reference example will be described in detail.
First, the outline of the manufacturing method is described.
As shown in FIG. 7, an electrode protective layer green sheet 535, a solid electrolyte plate green sheet 53, a spacer plate green sheet 54, and a heater substrate green sheet 55 are prepared.
[0039]
Each raw sheet is processed as follows.
That is, as shown in FIG. 8, the electrode forming printing section 530 is provided on the solid electrolyte plate raw sheet 53, and the heating element printing section 550 is provided on the heater substrate raw sheet 55, respectively.
Further, the raw sheet 54 for spacer plate is grooved to form a groove portion 540 in which one end serving as the reference gas chamber 100 is closed and the other end is opened.
[0040]
Thereafter, as shown in FIG. 9, the raw sheet 55 for the spacer plate is laminated on the raw sheet 55 for the heater substrate, and further, the raw sheet 53 for the solid electrolyte plate and the raw sheet 535 for the electrode protection layer are further laminated. As shown in (a), it is bonded with an adhesive to form an unfired laminate.
The obtained unfired laminate is divided into gas sensor element units as shown in FIG. 9B, and the obtained individual pieces 56 are fired to obtain the gas sensor element 1 as shown in FIG. 9C. obtain.
[0041]
This will be described in detail below.
Each raw sheet 535, 53, 54, 55 as shown in FIG. 7 is prepared by an extrusion molding apparatus (not shown).
In FIG. 7, in order from the top of the drawing, an electrode protective layer raw sheet 535 (alumina composition thickness 0.15 mm), a solid electrolyte plate raw sheet 53 (zirconia composition thickness 0.2 mm), a spacer plate raw sheet 54. (Alumina composition thickness 1.5 mm) and raw sheet 55 for heater substrate (alumina composition thickness 0.2 mm) are described.
[0042]
The dimensions of the raw sheet 53 for the solid electrolyte plate, the raw sheet 54 for the spacer plate, and the raw sheet 55 for the heater substrate are 70 mm × 90 mm, and the dimension of the raw sheet 535 for the protective layer is 70 mm × 35 mm.
The spacer plate raw sheet 54 is adjusted to the above dimensions after the groove processing described below is performed.
[0043]
Next, details of forming a groove 540 for the reference gas chamber 100 by performing groove processing on the raw spacer plate sheet 54 will be described.
First, the water content of the spacer plate raw sheet 54 immediately after extrusion is adjusted.
As shown in FIG. 10, the raw sheet 54 is placed on a legged tray 549 made of punching metal, placed in an oven maintained at a temperature of 50 degrees with a maximum of 10 trays 549, and dried. To do.
By this drying, the moisture content of the raw sheet 54 is set to 11 ± 0.5%. If the amount of water is too small, the raw sheet 54 may be cracked, and if the amount of water is large, the shape may not be stable.
After the drying is finished, the raw sheet 54 is cut into a predetermined size.
[0044]
Next, the metal mold | die used for the grooving press work is demonstrated.
As shown in FIG. 11, the mold includes an upper mold 61 and a lower mold 62, and a groove-forming convex portion 611 is provided on the mold surface 610 of the upper mold 61.
A lower auxiliary tool 629 is disposed around the lower mold 62, and an upper auxiliary tool 619 is attached to the side opposite to the mold surface 610 of the upper mold 61. A packing 628 is disposed around the mold surface 620 of the lower mold 62.
[0045]
The raw sheet 54 is set with the release sheet 545 sandwiched between the mold surface 620 of the lower mold 62 of the mold in such a state.
Subsequently, the upper die 61 is set on the lower die 62 and press molding is performed. At this time, the mold temperature was 80 ° C., the molding pressure was 77 MPa, and the molding time was 15 seconds. After the completion of molding, the mold is opened, the raw sheet 54 with grooves formed is taken out, and the release sheet 545 is peeled off.
[0046]
Again, the raw sheet 54 was placed on a tray with legs made of punching metal (using the same tray 549 as in FIG. 10), and the trays were stacked up to 10 levels at maximum. This is dried in an oven maintained at 95 ° C. for 2 hours.
The green sheet 54 after the drying is wavy, and the surface is uneven. In order to remove the waviness and unevenness, a smoothing press is applied to the raw sheet 54 by the following procedure.
[0047]
As shown in FIG. 12, the upper and lower surfaces of the raw sheet 54 are sandwiched between release sheets 545 and set in a flat press mold. In this flat press mold, the mold surfaces 630 and 640 of the upper mold 63 and the lower mold 64 are respectively configured to be flat.
Then, the raw sheet 54 sandwiched between the release sheets 545 is disposed on the mold surface 640 of the lower mold 64, the upper mold 63 is set, and flat pressing is performed. At this time, the mold temperature was 80 ° C., the pressure was 8.5 MPa, and the time was 15 seconds.
After flat pressing, the mold is opened, the release sheet 545 is peeled off, and the spacer raw sheet 54 is taken out.
Thereafter, the groove pitch, groove shape, sheet warpage (need to be 1 mm or less), sheet surface roughness (need to be 5 μm or less), and appearance inspection are performed to remove defective products.
[0048]
Next, a printing unit 530 for the gas side electrode to be measured and the reference gas side electrode, for each terminal portion, and for a lead portion connecting the terminal portion and the electrode is provided on the solid electrolyte plate raw sheet 53. This printing part was formed by screen-printing a Pt paste, which is a conductive paste, on the raw sheet 53.
Similarly, for the heater substrate raw sheet 55, the lead portion and the terminal portion printing portion 550 used when the heater is energized and the Pt paste, which is a conductive paste, are used. The green sheet 55 was formed by screen printing.
[0049]
An adhesive is applied to the entire surface of each of the green sheets 535, 53, 54, and 55 processed as described above and laminated as shown in FIG. The unfired laminated body thus obtained is cut and separated into one gas sensor element as shown in FIG. 9B.
The obtained piece 56 is fired at 1470 ° C. for 2 hours to obtain the gas sensor element 1.
[0050]
The effect of this example will be described.
In the manufacturing method described above, the spacer plate raw sheet 54 is provided with a groove for forming a reference gas chamber. The groove is formed in the spacer plate raw sheet 54 as a recess that does not penetrate. Unlike the conventional configuration shown in FIG. 16 described above, the reference gas chamber is constituted by a groove provided in the raw sheet 54 for spacers, so that various defects and troubles due to separation of the spacer plate and the alumina substrate can be eliminated. .
Further, since the raw sheets 535, 53, 54, and 55 are bonded with an adhesive, the sheets are strongly bonded to each other, and various defects and troubles due to peeling between the sheets are hardly caused.
[0051]
Embodiment 3
This example describes a case where cutting is selected as the groove processing method for the raw sheet 54 in the method for manufacturing the gas sensor element described in the second embodiment.
FIG. 13 shows a cutting blade 7 for cutting used in this example.
The cutting blade 7 includes a dodecagonal main body 70, four protrusions 71 provided on the circumferential side surface of the main body 70, and a diamond blade 711 provided for the protrusion 71.
FIG. 14 shows the shape of the diamond blade 711 viewed from the direction S shown in FIG.
[0052]
As shown in FIG. 15, the cutting blade 7 is moved in the direction T2 while rotating the cutting blade 7 in the arrow T1 direction from one end of the raw sheet 54 to the other end as shown in FIG. The cutting blade 7 is stopped at a desired position, that is, when a groove having a length necessary for the reference gas chamber is formed by cutting, and the cutting blade 7 is pulled up above the green sheet 54.
[0053]
At this time, as shown in the above-described third embodiment, when a raw sheet is prepared in a size that allows a plurality of gas sensor elements to be taken, one cutting blade 7 is used several times in forming each groove. Although a desired number of grooves can be formed, although not shown in the figure, it is better to simultaneously perform a plurality of grooves using a desired number of cutting blades 7 configured to be operable in conjunction with each other.
Except the groove processing of the raw sheet 54, it is the same as the second embodiment.
[0054]
In the manufacturing method according to this example, since the groove processing is performed by cutting using the cutting blade 7, the groove pitch and the groove shape can be processed with high accuracy.
The other operations and effects are the same as those of the second embodiment.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view of a gas sensor element in a reference example (a cross-sectional view taken along line BB in FIG. 2).
FIG. 2 is a cross-sectional explanatory view of the gas sensor element in the reference example (a cross-sectional view taken along the line AA in FIG. 1).
FIG. 3 is an explanatory diagram of main parts of a corner portion of a reference gas chamber in a reference example .
FIG. 4 is a cross-sectional explanatory view of a gas sensor in a reference example .
FIG. 5 is an explanatory diagram of a gas sensor element that can be used as an A / F sensor element in a reference example .
[6] implementation in embodiments 1, (a) a main portion explanatory view of a corner portion of the reference gas chamber, cross-sectional view of (b) a gas sensor element.
7 is a perspective view of each raw sheet in Embodiment 2. FIG.
FIG. 8 is a perspective view of each raw sheet provided with a printing portion and a groove portion in Embodiment 2 ;
FIG. 9 is an explanatory diagram when a gas sensor element is manufactured by laminating, dividing, and baking each raw sheet in the second embodiment.
10 is an explanatory diagram when drying a raw sheet in Embodiment 2 ; FIG.
FIG. 11 is an explanatory diagram when a groove is provided in a raw sheet in Embodiment 2 ;
FIG. 12 is an explanatory diagram when flat pressing a raw sheet provided with a groove in Embodiment 2 ;
FIG. 13 is an explanatory diagram showing a cutting blade used when providing a groove in Embodiment 3 .
14 is an explanatory view showing a diamond blade as a cutting blade in Embodiment 3. FIG.
FIG. 15 is an explanatory view showing the processing of the groove portion using the cutting blade in the third embodiment.
FIG. 16 is a perspective development view of a conventional gas sensor element.
[Explanation of symbols]
1. . . Gas sensor element,
10. . . Reference gas chamber,
100. . . Corner,
101. . . Open end,
102. . . Closed end,
11. . . Measured gas side electrode,
12 . . Reference gas side electrode,
13. . . Solid electrolyte plate,
14 . . Spacer plate,
15. . . Heater substrate,
150. . . Heating element,

Claims (4)

A solid electrolyte plate having a measured gas side electrode in contact with the measured gas and a reference gas side electrode in contact with the reference gas;
A reference gas chamber facing the reference gas side electrode, having one end as a closed end and the other end as an open end opened to the outside of the gas sensor element, and configured to introduce a reference gas A spacer plate with
A gas sensor element in which a heater substrate having a heating element that generates heat when energized is laminated,
The corner portion at the closed end of the reference gas chamber is formed by a curved surface in the width direction .
Further, in the cut surface along the plane parallel to the longitudinal direction passing through the center in the width direction of the reference gas chamber and perpendicular to the width direction, the corner in the longitudinal direction at the closed end is constituted by a curved surface and The radius of curvature of the gas sensor element is 1 mm to 20 mm. A solid electrolyte plate having a measured gas side electrode in contact with the measured gas and a reference gas side electrode in contact with the reference gas;
A reference gas chamber facing the reference gas side electrode, having one end as a closed end and the other end as an open end opened to the outside of the gas sensor element, and configured to introduce a reference gas A spacer plate with
A heater substrate with a heating element that generates heat when energized is laminated,
The corner at the closed end of the reference gas chamber has a curved surface in the width direction ,
In addition, in the cut surface along the plane parallel to the longitudinal direction passing through the center in the width direction of the reference gas chamber and perpendicular to the width direction, the corner in the longitudinal direction at the closed end is formed by a curved surface. In manufacturing a gas sensor element having a curvature radius of 1 mm to 20 mm ,
Prepare a raw sheet for the solid electrolyte plate, a raw sheet for the spacer plate, and a raw sheet for the heater substrate,
A printing section for electrode formation is provided on the raw sheet for the solid electrolyte plate, and a printing section for the heating element is provided on the raw sheet for the heater substrate.
Groove processing is performed on the raw sheet for the spacer plate to form a groove portion having a closed end and an open end that serve as a reference gas chamber, and a corner portion of the closed end is formed by a curved surface.
A raw sheet for a spacer plate is laminated on a raw sheet for a heater substrate, and further, a raw sheet for a solid electrolyte plate is laminated on the raw sheet and bonded together with an adhesive to form an unfired laminate.
Thereafter, the unfired laminated body is fired, and the method for producing a gas sensor element.   3. The method of manufacturing a gas sensor element according to claim 2, wherein the groove processing is performed by cutting. Oite to claim 2, the groove processing method of manufacturing a gas sensing element and performing the press working.

Images