JP2001281208A - Laminated-type oxygen sensor element, its manufacturing method, and oxygen sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated-type oxygen sensor element to suppress current leakage between solid electrolyte layers, its manufacturing method, and an oxygen sensor in which leakage does not occur between the element and main body metal fixture. SOLUTION: An oxygen concentration cell element in which a detecting electrode and reference electrode are formed and a ceramic heater in which a heating resistor embedded in an insulating layer is sandwiched by heater main body layers are laminated. An insulating coating 29 is formed in both side surfaces 27a and 27b and a face on the side to be exposed to a gas to be measured. Both longitudinal edges of the surface of the ceramic heater in which heater energizing terminals 25a and 25b are formed are chamfered. The insulating coating 29 is also formed in the surfaces formed by the chamfering in the laminated-type oxygen sensor element. Such the element superior in insulation is used to obtain the compact oxygen sensor in which leakage does not occur even if the element and main body metal fixture are close to each other and the minimum distance between them is 1 mm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stacked oxygen sensor element for detecting the concentration of oxygen contained in exhaust gas discharged from an internal combustion engine of an automobile or the like, a method for manufacturing the same, and an oxygen sensor.

[0002]

2. Description of the Related Art Conventionally, various oxygen sensors have been developed for use in controlling the air-fuel ratio of an internal combustion engine of an automobile or the like. As one form of such an oxygen sensor, a long oxygen concentration cell element in which a detection electrode is formed on one surface and a reference electrode is formed on the other surface of an element body layer made of a solid electrolyte, Heating resistor buried in
A laminated oxygen sensor element (hereinafter, also simply referred to as an “element”) formed by laminating a long ceramic heater formed in a shape sandwiched between a first heater main body layer and a second heater main body layer formed of a solid electrolyte. ) Is known.

[0003]

By the way, in constructing an oxygen sensor, this type of element has a part (more specifically, a detecting portion) protruding inside a metal shell for attachment to an exhaust pipe or the like. Therefore, both side surfaces and one end surface of the element are directly exposed to the gas to be measured. As a result, while the use of the oxygen sensor is repeated in an actual use environment, carbon may adhere to both side surfaces and one end surface of the element.

However, since this kind of device is formed by laminating a plurality of solid electrolyte layers, carbon adheres to both side surfaces and one end surface of the device, and conductive carbon adheres over each solid electrolyte layer. If this occurs, the output current or the leakage current of the heater may leak from one solid electrolyte layer to the other solid electrolyte layer, making it impossible to detect the oxygen concentration. In addition, since the solid electrolyte has a property that the insulating property is reduced when the temperature exceeds a specific temperature range due to a rise in temperature, when the element is exposed to a high temperature for a long time, one solid electrolyte layer is removed from the other solid electrolyte. There is a possibility that a current leaks to the layer, and the oxygen concentration cannot be detected, or blackening is induced, thereby lowering the durability of the element itself.

Further, in recent years, due to the tightening of exhaust gas regulations and the like, it has become necessary to install an oxygen sensor even in an internal combustion engine having a small displacement, for example, a two-wheeled vehicle, and it is required to reduce the size of the oxygen sensor itself. Therefore, the distance (gap) between the inner peripheral surface of the metal shell in which the element is disposed inside and the outer peripheral surface of the element cannot be sufficiently taken.
If carbon or any conductive foreign matter adheres to both sides of the device (that is, a surface formed by laminating the solid electrolyte layers with both sides exposed), the inside of the device and the metal shell may be damaged. There is a concern that a leak may occur between the ceramic heater and the peripheral surface, which may adversely affect energization of the ceramic heater and detection of oxygen concentration.

The present invention has been made to solve the above-mentioned conventional problems, and it is possible to sufficiently secure insulation on both sides of a stacked oxygen sensor element and end faces exposed to a gas to be measured. It is an object of the present invention to provide a stacked oxygen sensor element capable of suppressing current leakage from one solid electrolyte layer to the other solid electrolyte layer due to carbon adhesion. Also, in the oxygen sensor incorporating this element, even when the distance between the outer peripheral surface of the element and the inner peripheral surface of the metal shell is short, oxygen that does not cause leakage between the element and the metal shell. It is intended to provide a sensor.

[0007]

Means for Solving the Problems and Effects of the Invention In the stacked oxygen sensor element of the first invention, a sensing electrode is provided on one surface of a device body layer made of a solid electrolyte, and a reference electrode is provided on the other surface. A long oxygen concentration cell element formed and a heating element embedded in an insulating layer are sandwiched between a first heater body layer and a second heater body layer made of a solid electrolyte. A multilayer oxygen sensor element comprising a stack of ceramic heaters, wherein an insulating film is formed on at least both side surfaces and an end surface on the side exposed to the gas to be measured.

The insulating film is formed on both side surfaces of the element and an end surface on the side exposed to the gas to be measured. As a result, even when carbon adheres to both side surfaces or the end surfaces, the carbon adheres to the surface of the insulating film, and does not directly adhere to the surface (exposed surface) of the solid electrolyte layer.
As a result, it is possible to suppress the output current and the leakage current of the heater from leaking from one solid electrolyte layer to the other solid electrolyte layer through carbon.

As the solid electrolyte constituting the solid electrolyte layer having oxygen ion conductivity, ceramics mainly composed of zirconia are often used, and the solid electrolyte layer mainly composed of zirconia usually has a temperature of 200 ° C. Exposure to a temperature range higher than this tends to decrease the insulation. However, by covering both side surfaces of the element and the end surfaces on the side exposed to the gas to be measured with the insulating film, it is possible to suppress the leakage of the output current between the solid electrolyte layers and the leakage current of the heater. It is possible to suppress the occurrence of blackening and the like.

It is preferable that the insulating film is mainly composed of a material having excellent insulating properties such as alumina and mullite. In the present specification, “main component” means a component having the highest mass content, and does not necessarily mean a component occupying 50% by mass or more. In addition, the thickness of the insulating film is preferably 3 μm or more from the viewpoint of sufficiently securing insulation. In addition, as the upper limit of the thickness, it is preferable that the thickness is thicker in consideration of insulation properties and releasability, but if the thickness is extremely large, manufacturing waste will occur. Good.

The insulating film can be formed not only on both sides of the element and the end face exposed to the gas to be measured, but also on the end face opposite to the end face exposed to the gas to be measured. .
However, since this end face of the element is usually separated from the heat-generating portion of the heat-generating resistor and is not exposed to the gas to be measured even when it is attached to an exhaust pipe or the like as an oxygen sensor, the element is particularly When the length (dimension) in the longitudinal direction of the solid electrolyte layer exceeds 40 mm, the solid electrolyte layer itself can maintain a sufficient insulating property by heat drawing of the solid electrolyte layer itself, so that the formation of an insulating film is not essential. However, when the length of the element in the longitudinal direction is 40 mm or less, it is considered that the entire solid electrolyte layer constituting the element is activated, so that the element is exposed to both sides of the element and the gas to be measured. It is preferable to form an insulating film on the end face opposite to the end face exposed to the gas to be measured, in addition to the end face on the side of the element, from the viewpoint of improving the insulation of the element.

In the case where at least one of both longitudinal edges of the front and back surfaces of the laminated oxygen sensor element is sometimes chamfered, the insulating film is formed by chamfering as in the second invention. Preferably, it is formed up to the surface.

The reason for chamfering in this manner is to effectively reduce excessive bending stress applied from the outside of the element, prevent breakage of the element, and improve the strength of the element itself. However, when this chamfer is formed, since the surface formed by the chamfer exposes the solid electrolyte layer, carbon may adhere to the surface on which the chamfer is formed in an actual use environment, It is feared that the detection of the oxygen concentration is adversely affected or blackening is induced. Therefore, when the chamfer is formed as described above, such a concern is suppressed by forming an insulating film on the surface formed by the chamfer. The shape of the chamfer is not particularly limited, and may be any of a C-chamfer shape that is substantially flush with each other and an R-surface shape that is formed in a convex shape.

According to a third aspect of the present invention, there is provided a method for manufacturing a laminated oxygen sensor element, comprising forming an unfired electrode pattern to be a detection electrode and a reference electrode on the front and back surfaces of an unfired solid electrolyte sheet to be an element body layer, An unfired body of a battery element is formed, and an unfired insulating layer is formed between the unfired solid electrolyte sheets to be the first heater body layer and the second heater body layer. An unsintered body of the ceramic heater is formed, and the unsintered body of the oxygen concentration cell element and the unsintered body of the ceramic heater are laminated to form an unsintered laminate. In addition, an insulating paste is applied to an end surface to be exposed to the gas to be measured, and then the resultant is integrally fired.

With this configuration, when forming an insulating film on both side surfaces of the stacked oxygen sensor element and the end surface on the side exposed to the gas to be measured, the green body as an oxygen concentration cell element and the green body as a ceramic heater are formed. After applying an insulating paste to both sides of the unsintered laminate and the end surface to be exposed to the gas to be measured in the stage of the unsintered laminate in which the body is laminated (that is, before the sintering). And firing. This makes it possible to adopt a system in which the formation of the insulating film and the sintering of the unsintered laminated body are simultaneously performed and integrated, so that only one sintering is required, and the number of steps can be significantly reduced. The application of the insulating paste can be performed by screen printing or the like.

If it is necessary to chamfer at least one of the longitudinal edges of the front and back surfaces of the stacked oxygen sensor element, as in the fourth invention, at least one of the front and back surfaces of the unfired stacked body is required. Both edges in the longitudinal direction are chamfered, and an insulating paste is applied to both side surfaces of the unfired laminate and the end surface to be exposed to the gas to be measured, and further to the surface formed by the chamfering, and then fired integrally. It is good to manufacture by doing.

In this configuration, at the stage of the unsintered laminate in which the unsintered body serving as the oxygen concentration cell element and the unsintered body serving as the ceramic heater are stacked (ie, before firing),
Chamfering both longitudinal edges of the front and back surfaces of the unfired laminate, then insulating both sides of the unfired laminate and the end surfaces to be exposed to the gas to be measured, and further the surfaces formed by the chamfering After applying the conductive paste, baking is performed. This makes it possible to adopt a system in which the formation of the insulating film and the sintering of the unsintered laminated body are simultaneously performed and integrated, so that only one sintering is required, and the number of steps can be significantly reduced. The application of the insulating paste can be performed by screen printing or the like.

An oxygen sensor according to a fifth aspect of the invention is characterized in that the stacked oxygen sensor element according to the first or second aspect of the invention is arranged inside a metal shell. The structure, mounting method, and the like of the oxygen sensor are not particularly limited.For example, the element is disposed inside the metal shell, and the mounting electrode formed on the outer peripheral surface of the metal shell includes a detection electrode and a detection electrode. An oxygen sensor that can be attached to an exhaust pipe such that a detection portion formed by a reference electrode protrudes into the exhaust pipe or the like is given.

In such an oxygen sensor, since an insulating film is formed on both sides of the element constituting the sensor and the end face on the side exposed to the gas to be measured, a carbon film is formed on both sides of the element. Also, even when any conductive foreign matter is attached, they are attached to the surface of the insulating film and do not directly adhere to the surface (exposed surface) of the solid electrolyte layer. As a result, it is possible to suppress the occurrence of leakage through carbon or the like between the inner peripheral surface of the metal shell and the element. Especially, in recent years, in the case where the oxygen sensor is required to be downsized, the minimum distance between the inner peripheral surface of the metal shell and the outer peripheral surface of the element has to be reduced to 1.0 mm or less. By configuring the oxygen sensor using the element of the present invention, it is possible to reliably suppress the leak between the inner peripheral surface of the metal shell and the element.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a stacked oxygen sensor element of the present invention and an oxygen sensor incorporating the same will be described in detail with reference to examples. 1. FIG. 1 shows an oxygen sensor incorporating a stacked oxygen sensor element of the present invention, which is attached to an exhaust pipe of an internal combustion engine.
FIG. 2 is a cross-sectional view showing an example of an oxygen sensor B commonly called a λ-type oxygen sensor used for measuring the oxygen concentration in exhaust gas.

The stacked oxygen sensor element A incorporated in the oxygen sensor B has an insertion hole 32 formed in the metal shell 3 so that the front side projects from the tip of the metal shell 3.
And the space between the inner peripheral surface of the insertion hole 32 and the outer peripheral surface of the element A is sealed by a sealing material layer 41 mainly composed of glass (for example, crystallized zinc silica borate glass). ing. Metallic double protectors 61 and 62 covering the protruding portion of the element A are fixed to the outer periphery of the distal end portion of the metal shell 3 by laser welding or the like. The protectors 61 and 62 have a cap shape, and the exhaust gas flowing through the exhaust pipe is protected at the tip and around the protectors 61 and 6.
2 are formed with ventilation holes 61a and 62a. On the other hand, the rear end portion of the metal shell 3 is inserted inside the front end portion of the outer cylinder 7, and the overlapped portion is joined by laser welding or the like in the circumferential direction. At the outer peripheral portion of the metal shell 3, a mounting screw portion 31 for screwing and mounting the oxygen sensor B (metal shell 3) into the exhaust pipe is screwed. In the present embodiment, the shortest distance S between the inner peripheral surface of the metal shell 3 and the element A is 0.3 mm.

As for the element A, the first connector 51, the longitudinal thin metal plate 52, the second connector portion 53 and the insulating plate (not shown) (these are collectively referred to as "external terminals")
) And an external circuit (not shown) via a lead wire 9. The four lead wires 9 extend through the grommet 8 located at the rear end side of the outer cylinder 7.

In the longitudinal direction (axial direction) of the element A, the element A is adjacent to at least one side of the sealing material layer 41 (in this embodiment, on the end face side of the sealing material layer 41 near the detection portion X). A buffer layer 42 made of a porous inorganic substance (for example, a compact formed of an inorganic substance powder of talc talc or a porous calcined body) is formed. This buffer layer 42
Supports the element A projecting in the axial direction from the sealing material layer 41 so as to wrap the element A from the outside, and excessive bending stress and thermal stress
It plays a role in suppressing the participation of the user.

2. Structure of Stacked Oxygen Sensor Element Next, a stacked oxygen sensor element which is a main part of the present invention will be described with reference to FIG. FIG. 2 is an exploded perspective view of an element A provided in the oxygen sensor B shown in FIG. 1, and this element A is composed of an oxygen concentration cell element 1 and a ceramic heater 2.

The oxygen concentration cell element 1 includes an oxygen concentration cell solid electrolyte layer 11 mainly composed of zirconia having oxygen ion conductivity, and one end of the oxygen concentration cell solid electrolyte layer 11 (FIG. 1). The detection electrode portion 131a and the reference electrode portion 131b are formed directly on the front and back surfaces (the side protruding from the front end of the metal shell 3 in FIG. 1), and constitute the detection portion X in FIG. Conductive lead portions 132a and 132b extend in the longitudinal direction of the solid electrolyte layer 11 for an oxygen concentration battery, respectively, on the detection electrode portion 131a and the reference electrode portion 131b. However, each of these conductor lead portions 13
2a and 132b are solid electrolyte layers 11 for oxygen concentration cells.
Are formed via a first insulating layer for oxygen concentration cells 12a and a second insulation layer for oxygen concentration cells 12b. The first insulating layer 12a for oxygen concentration cells and the second insulation layer 12b for oxygen concentration cells are mainly composed of alumina having excellent insulation properties.

The end of the conductor lead 132a is connected to an external terminal (not shown) for connecting an external circuit, and constitutes a signal extraction terminal 133a electrically connected to the detection electrode 131a. is there. Also, the lead portion 13
2b is connected to an external terminal via a through hole 15 penetrating through the solid electrolyte layer 11 for oxygen concentration cells, the first insulation layer 12a for oxygen concentration cells, and the second insulation layer 12b for oxygen concentration cells. Connected to signal extraction terminal 14.

On the other hand, the ceramic heater 2 includes a heating resistor 21 made of platinum, a platinum alloy, or the like. The heating resistor 21 is made of a first insulating layer mainly composed of alumina having excellent insulation properties. 22a and the second insulating layer for heater 22b. Further, the heating resistor 21 sandwiched between the insulating layers is sandwiched between the first heater main layer 23a and the second heater main layer 23b mainly composed of zirconia and then made of a ceramic mainly composed of alumina. It has a multilayer structure sandwiched between the heater third insulating layer 24a and the heater fourth insulating layer 24b.

The heating resistor 21 includes a fourth heater insulating layer 24b, a second heater main body layer 23b, and a third heater layer.
Through holes 26a and 26b penetrating insulating layer 22b
Are electrically connected to the heater power supply terminals 25a and 25b connected to the external terminals for the external circuit.

Although not shown in the exploded perspective view of FIG. 2, as schematically shown in FIG. 3, a laminate of the oxygen concentration cell element 1 and the ceramic heater 2 (that is, element A) is shown. Insulating films 29 are formed on both side surfaces and end surfaces on the side exposed to the gas to be measured. The insulating film is mainly composed of alumina having excellent insulating properties. Further, if the thickness of the insulating film is 3 μm or more, sufficient insulating properties can be ensured. Note that FIG.
In FIG. 1, the chamfers formed on at least one longitudinal edge of the front and back surfaces of the element A are omitted, and the chamfers will be described later.

3. Manufacture of stacked gas sensor element Preparation of first unsintered body to be oxygen concentration cell element Oxygen concentration cell using raw material obtained by kneading zirconia powder in which a stabilizer such as yttria or calcia is solid-dissolved together with an organic binder 5 which becomes the solid electrolyte layer 11 for
An unsintered solid electrolyte sheet large enough to cut out individual elements was formed. Detection electrode section 131 of this sheet
On the front and back surfaces excluding the portion where the a and the reference electrode portion 131b are formed, using an insulating paste mainly containing alumina for 5 elements, an organic binder such as polyvinyl butyral, and an organic solvent such as butyl carbitol. Then, the coating film to be the oxygen concentration cell insulating layers 12a and 12b was printed and dried. Thereafter, a through hole serving as a through hole 15 for five elements is formed at a predetermined position of the unsintered solid electrolyte sheet on which the coating films are formed, and the inner wall surface and the opening edge of the through hole 15 are covered. The insulating paste was printed and dried.

Further, the oxygen concentration cell insulating layers 12a and 12a
A conductive paste containing platinum or a platinum alloy as a main component is printed and dried in a predetermined area on a coating film 2b (including a coating film made of an insulating paste on the through-hole 15) through a predetermined pattern. Thus, a conductor pattern (coating) to be the detection electrode portion 131a, the reference electrode portion 131b, the lead portions 132a and 132b, and the signal extracting terminals 133a and 14 was formed. As a result, a first unfired body to be the oxygen concentration battery element 1 was obtained.

Preparation of Second Unsintered Body to Be Ceramic Heater Next, the same unsintered solid electrolyte sheet as described above to be the second heater body layer 23b is formed, and the same insulating material as described above is formed on the front and back surfaces thereof. The paste is printed and dried, and the third insulating layer for heater 22b and the fourth insulating layer for heater 24b are formed.
Was formed. Thereafter, at predetermined positions of the unsintered solid electrolyte sheet on which these coating films are formed, through holes serving as through holes 26a and 26b for five elements are formed,
The insulating paste was printed and dried so as to cover the inner wall surfaces of the through holes 26a and 26b and the edges of the openings.

Further, a coating film (through hole 26a) to be the third insulating layer 22b for heater and the fourth insulating layer 24b for heater is used.
And a conductive paste similar to that described above in a predetermined pattern on a required area (including a coating film made of an insulating paste on the through-holes 26b and 26b).
A conductor pattern (coating) to be a pair of heater energization terminals 25a and 25b was formed. Then, a layer to be the first insulating layer 22a for the heater is printed on the conductor pattern to be the heating resistor 21, and the same unsintered solid electrolyte sheet as described above to be the first heater body layer 23a is laminated and pressure-bonded under reduced pressure. did. As a result, a second green body to be the ceramic heater 2 was obtained.

Assembling, Degreasing, and Firing A layer to be the third insulating layer 24a for the heater was printed on the second green body, and the first green body was laminated and pressure-bonded to obtain a laminated body. Then, this laminate is cut to form the element A,
Five unfired laminates were cut out. Next, C-chamfering was performed on both ends in the longitudinal direction of the surface (outermost surface) of the unfired solid electrolyte sheet, which is to be the second heater main body layer 23b of each unfired laminate, on the side where the heater energizing terminals are formed (outermost surface). . Then, the same insulating paste as described above is screen-printed and dried on both sides of the unsintered laminate and the end faces to be exposed to the gas to be measured, and further, the faces formed by chamfering, The temperature of the unsintered laminated body in this state is increased at 20 ° C./hour in an air atmosphere, and after being degreased (debinding) while being held at a maximum temperature of 450 ° C. for 1 hour, 15
The element A was obtained by baking at 00 ° C. for 1 hour.

FIG. 4 schematically shows a partially enlarged view of the vicinity of a pair of heater conducting terminals 25a and 25b formed on the ceramic heater 2 in the element A obtained in the above-described manufacturing process. In the element A, both longitudinal edges of the surface of the ceramic heater 2 on which the heater power supply terminals 25a and 25b are formed are chamfered, and a chamfered portion 27 is formed. An insulating film 29 is formed on the surface (chamfered portion 27) formed by the chamfering and on both side surfaces 28a and 28b.

Incidentally, in the case of the stacked oxygen sensor element,
In order to achieve conduction between the front and back surfaces of each solid electrolyte layer, a structure which is usually performed via through holes as in this embodiment is often employed. When conducting through the through hole in this way, as described in this embodiment, the conduction is performed after the inner wall surface and the opening edge of the through hole are covered with an insulating layer (insulating film). It is preferable to aim. By adopting such a configuration, the insulating property of the solid electrolyte layer near the through hole can be improved, and the insulating properties are covered by covering both side faces of the element and the end faces exposed to the gas to be measured. Synergistically with the effect of enhancing, the insulating properties of the entire device can be further enhanced. Although the present invention has been described with reference to the embodiment, the present invention is not limited to the embodiment, and it goes without saying that the present invention can be appropriately modified and applied without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of an oxygen sensor in which a laminated oxygen sensor element of the present invention is incorporated.

FIG. 2 is an exploded perspective view showing a stacked oxygen sensor element of the present invention.

FIG. 3 is a partially cutaway perspective view showing a laminated oxygen sensor element of the present invention.

FIG. 4 is an enlarged perspective view of a portion where a heater energization terminal is formed in the stacked oxygen sensor element of the present invention.

[Explanation of symbols]

A: stacked gas sensor element, 1; oxygen concentration cell element, 1
1; a solid electrolyte layer for an oxygen concentration cell; 12a; a first insulation layer for an oxygen concentration cell; 12b; a second insulation layer for an oxygen concentration cell;
13a; detection electrode, 13b; reference electrode, 2; ceramic heater, 21; heating resistor, 22a; first insulating layer for heater, 22b; second insulating layer for heater, 23a; first heater body layer, 23b; 2 heater body layer, 24a; third insulating layer for heater, 24b; fourth insulating layer for heater, 133a,
14; signal extraction terminal, 25a, 25b; heater section conduction terminal, 27a, 27b; chamfered section, 28a, 28b;
Side surface, 29; insulating film, B: oxygen sensor, 3: metal shell.

Continuing on the front page (72) Ryohei Aoki 14-18, Takatsuji-cho, Mizuho-ku, Nagoya-shi Inside Japan Special Ceramics Co., Ltd. F term (reference) 2G004 BB04 BC02 BE04 BE13 BE22 BF18 BG05 BJ03 BJ05 BM07

Claims (6)

[Claims] 1. A long oxygen concentration cell element having a detection electrode on one surface and a reference electrode on the other surface of an element body layer composed of a solid electrolyte, and a heat generator embedded in an insulating layer. A laminated oxygen sensor element formed by laminating a resistor and a long ceramic heater formed so as to be sandwiched between a first heater body layer and a second heater body layer made of a solid electrolyte, A laminated oxygen sensor element, wherein an insulating film is formed on at least both side surfaces and an end surface on the side exposed to the gas to be measured. 2. The stacked oxygen sensor element according to claim 1, wherein at least one of both longitudinal edges of the front and back surfaces of the stacked oxygen sensor element is chamfered,
And a laminated oxygen sensor element in which the insulating film is formed on a surface formed by the chamfering. 3. An unsintered electrode pattern to be a detection electrode and a reference electrode is formed on the front and back surfaces of an unsintered solid electrolyte sheet to be an element body layer, and an unsintered body of an oxygen concentration cell element is formed. Between the unsintered solid electrolyte sheet to be the main body layer and the second heater main body layer, an unsintered heating resistor pattern to be the heating resistor is formed via the unsintered insulating layer,
A green body of the ceramic heater is formed, and the green body of the oxygen concentration cell element and the green body of the ceramic heater are laminated to form a green body.
A method for manufacturing a laminated oxygen sensor element, comprising applying an insulating paste to both sides of an unfired laminate and an end face to be exposed to a gas to be measured, and then firing the laminated paste integrally. 4. A method of chamfering at least one of both longitudinal edges of the front and back surfaces of the unsintered laminated body, the both sides of the unsintered laminated body and the end faces to be exposed to the gas to be measured, and the chamfering. 4. The method according to claim 3, wherein an insulating paste is applied to the formed surface, and then fired integrally. 5. An oxygen sensor comprising the stacked oxygen sensor element according to claim 1 disposed inside a metal shell. 6. The oxygen sensor according to claim 5, wherein
An oxygen sensor wherein a minimum distance between an inner peripheral surface of the metal shell and an outer peripheral surface of the stacked oxygen sensor element is 1.0 mm or less.