JP7154186B2 - Gas sensor and method for manufacturing gas sensor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gas sensor and a method of manufacturing a gas sensor suitably used for detecting the gas concentration of a specific gas contained in combustion gas or exhaust gas from, for example, a combustor or an internal combustion engine.

2. Description of the Related Art Conventionally, gas sensors have been used to detect the concentration of specific components (such as oxygen) in exhaust gas from internal combustion engines. This gas sensor is manufactured by assembling a sensor element to a metal shell. The sensor element is formed by having a solid electrolyte and a pair of electrodes, but the thickness and dimensions of the electrodes vary slightly for each individual sensor element, and the output characteristics such as the electromotive force generated between both electrodes also vary slightly. fluctuate. Therefore, a technique is known in which output characteristics are measured for each individual sensor element and the information is attached to the outer surface of the element or gas sensor (see Patent Document 1). When a controller is connected to this gas sensor, this output characteristic information is read to calibrate the controller (output value correction and rank correction).

Japanese Patent Application Laid-Open No. 2007-212405

However, when the output characteristic information for each individual sensor element is attached to the element itself, the sensor element is hidden inside the outer cylinder or the like when the sensor element is assembled to the gas sensor. In general gas sensors, the outer cylinder is joined to the metal shell by caulking or welding, so the output characteristic information cannot be read unless the gas sensor is destroyed and the outer cylinder is removed. There is
In addition, when the output characteristic information is attached to the outer surface of the gas sensor, it is necessary to store the output characteristic information in the state of the sensor element before assembly. there is a risk of it happening.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a gas sensor and a method of manufacturing a gas sensor that can attach at least information related to an individual sensor element to the outer surface of a gas sensor or an external component integrated with the gas sensor without error.

In order to solve the above-mentioned problems, the gas sensor of the present invention is a sensor element having a first information section storing first information, which is information related to the individual sensor element, attached to the outer surface of the sensor element. an element, a metal shell that holds the sensor element so that the first information part is exposed, a case joined to the metal shell while covering the outer periphery of the sensor element including the first information part, wherein a second information section storing second information including at least a part of the first information is attached to the outer surface of the gas sensor or an external component integral with the gas sensor ; The first information includes manufacturing information of the sensor element, and the second information includes the first information and output characteristic information not included in the first information .

According to this gas sensor, the first information portion is attached to the outer surface of the sensor element, and the second information including at least a part of the first information is provided on the outer surface of the gas sensor (or an external component integrated with the gas sensor). A stored second information portion is attached.
Therefore, even if the sensor element is assembled to the gas sensor and the first information part is concealed, if the second information part attached to the outer surface of the gas sensor or the external part integrated with the gas sensor is read, the information can be read even after assembly. , the first information can be read non-destructively. In addition, since the second information includes at least part of the first information of the individual sensor element, it is possible to prevent the sensor element from being mixed up and attaching the wrong second information portion to another gas sensor.
As a result, the information relating to the individual sensor element can be attached to the outer surface of the gas sensor or the external component integral with the gas sensor without error.
The term "joined" means that the case is irremovably joined to the metal shell by welding or the like.

In addition, according to this gas sensor, each sensor element can be identified by using the manufacturing information as the first information, so management is facilitated. In addition, since the output characteristic information of the sensor element is included in the second information, the output characteristic information can be easily read after assembly to the gas sensor.

In the gas sensor of the present invention, the second information portion may be attached to the plane of the hexagonal portion of the metallic shell.
Since the plane of the hexagonal portion is not a curved surface such as that of the outer cylinder, the second information can be easily read by a camera or the like.

A method for manufacturing a gas sensor according to the present invention includes a step of attaching a first information portion storing first information, which is information related to an individual sensor element, to an outer surface of a sensor element; a first information reading step of reading information; before or after the first information reading step, a metallic shell holding step of holding the sensor element on the metallic shell so that the first information portion is exposed; After the holding step, the outer periphery of the sensor element including the first information portion is covered with a case to assemble the gas sensor, and the second information including at least part of the first information read in the first information reading step is read. and a step of providing a second information portion to the outer surface of the gas sensor or an external component integral with the gas sensor.

According to this gas sensor manufacturing method, the first information is read before the sensor element is attached to the gas sensor and the first information section is hidden, and the second information section is attached based on the read first information. This solves the problem that the first information cannot be read after the gas sensor is assembled. In addition, it is possible to prevent attaching the wrong second information part to a different gas sensor by mixing up the sensor element.
As a result, the information relating to the individual sensor element can be attached to the outer surface of the gas sensor or the external component integral with the gas sensor without error.

According to the present invention, at least information relating to the individual sensor element can be attached without error to the outer surface of the gas sensor or the external component integrated with the gas sensor.

1 is a cross-sectional view along the axial direction of a gas sensor (oxygen sensor) according to an embodiment of the present invention; FIG. FIG. 4 is a diagram showing a mode of reading an intermediate product of a gas sensor in which a sensor element is held by a metal shell, a first information section, a second information section, and a first information section; FIG. 10 is a diagram showing another aspect of attaching a second information section to a gas sensor or an external component integral with the gas sensor;

Embodiments of the present invention will be described below.
FIG. 1 is a cross-sectional view along the direction of the axis O of a gas sensor (oxygen sensor) 1 according to an embodiment of the present invention, and FIG. It is a front view.

As shown in FIG. 1, the gas sensor 1 includes a plate-shaped sensor element 100 extending in the direction of the axis O, a tubular metallic shell 30 for holding the sensor element 100 inserted therein, and a distal end portion of the metallic shell 30. It has a protector 24 and the like attached to it.
The sensor element 100 has a detecting portion 100a having a solid electrolyte body and a pair of electrodes arranged on the solid electrolyte body on the front end side, and an electrode pad 102 (FIG. 2) on the rear end side.

The metal shell 30 is made of SUS430, and has a cylindrical shape with a male threaded portion 31 for attaching the gas sensor to the exhaust pipe and a hexagonal portion 32 to which an attachment tool is applied during attachment. The metal shell 30 is provided with a metal fitting side stepped portion 33 that protrudes radially inward. engaged. Inside the metal shell 30, a ceramic holder 35 and a talc 37 are arranged in order from the tip side. The ceramic holder 35 is provided with an axial hole along the axis O, through which the sensor element 100 is inserted.

By compressing and filling the metal shell 30 with the talc 37 , the sensor element 100 is fixed to the metal shell 30 and the sealability between the surface of the sensor element 100 and the inner surface of the metal shell 30 is ensured. be. A sleeve (insulating holder) 39 made of alumina is arranged on the rear end side of the talc 37 . The sleeve 39 is provided with an axial hole along the axis O, through which the sensor element 100 is inserted. The caulking portion 30 a on the rear end side of the metal shell 30 is bent inward, and the sleeve 39 is pressed toward the front end side of the metal shell 30 via the O-ring member 55 .

A metal protector 24 having a plurality of gas intake holes and covering the tip of the sensor element 100 protruding from the tip of the metal shell 30 is welded to the outer circumference of the metal shell 30 on the tip side. The protector 24 has a double structure, with an outer cylindrical protector 41 having a uniform outer diameter and a cylindrical inner protector 42 having a smaller diameter than the outer protector 41 and a cylindrical inner protector 42 having a bottom. are placed.
The protector 24 and the metal shell 30 can be joined by a method other than welding, such as crimping or press-fitting.

On the other hand, the front end side of an outer cylinder 25 made of SUS430 is inserted into the rear end side of the metallic shell 30 . The outer cylinder 25 has a distal end portion 25a having an enlarged diameter on the distal end side and is fixed to the metal shell 30 by laser welding or the like. A separator 50 is arranged inside the rear end side of the outer cylinder 25 , and a holding member 51 is interposed between the separator 50 and the outer cylinder 25 . This holding member 51 is fixed by the outer cylinder 25 and the separator 50 by engaging with the surface of the brim portion 50 a of the separator 50 facing the fore end and crimping the outer cylinder 25 .
The outer cylinder 25 and the metallic shell 30 can be joined by a method other than welding, such as crimping or press-fitting.

Further, through holes 50b for inserting the lead wires 11 to 15 are formed through the separator 50 from the front end side to the rear end side (the lead wires 14 and 15 are not shown). Connection terminals 16 for connecting the lead wires 11 to 15 and the electrode pads 102 are accommodated in the insertion holes 50b. Each of the lead wires 11 to 15 is connected to a connector (not shown) on the outside. An electric signal is input/output between a controller (external device) such as an ECU and each of the lead wires 11 to 15 via this connector. Although not shown in detail, each of the lead wires 11 to 15 has a structure in which the lead wire is covered with an insulating film made of resin.

Further, on the rear end side of the separator 50, a substantially cylindrical rubber cap 52 for closing the rear end side opening 25b of the outer cylinder 25 is arranged. The rubber cap 52 is fixed to the outer cylinder 25 by crimping the outer circumference of the outer cylinder 25 radially inward while being mounted inside the rear end of the outer cylinder 25 . The rubber cap 52 is also provided with insertion holes 52a for inserting the lead wires 11 to 15 respectively from the front end side to the rear end side.

FIG. 2 shows an intermediate product 1x of a gas sensor in which the sensor element 100 is held by the metal shell 30, the first information section 110, the second information section 70, and the manner in which the first information section 110 is read.
As shown in FIG. 2 , two electrode pads 102 are arranged on the rear end side of one main surface of the sensor element 100 so as to be spaced apart in the width direction. A first information section 110 consisting of a two-dimensional bar code is engraved with a laser at a portion exposed from the end.
Attachment of the first information section 110 to the sensor element 100 can be performed as follows.

First, before assembling this sensor element 100 to the metal shell 30, the bare sensor element 100 is set on a predetermined measuring jig, and the output characteristics are measured. In this example, the output characteristic is the Ip (detection) current flowing between the electrodes of the sensor element 100 in a predetermined gas atmosphere to be measured.
The control unit (computer) 210 attaches the first information (information related to the individual sensor element) assigned to each sensor element 100 to the corresponding sensor element 100 using a laser marking machine or the like, and also attaches the corresponding sensor element. The first information of 100 and the measured output characteristic information are associated and stored in the database 200 . An example of data 202 stored in database 200 is shown in FIG.

After that, the sensor element 100 flows through various processes, is assembled to the metal shell 30 so that the first information section 110 is exposed, and becomes an intermediate product 1x. 1 information is read.
The control unit 210 refers to the database 200, reads the output characteristic information associated with the read first information, and marks the plane of the hexagonal portion 32 of the metallic shell 30 of the intermediate product 1x with a laser marking machine or the like. An information unit 70 is attached. The second information stored in the second information section 70 includes the above-described first information and output characteristic information. Note that "storage" means that the first information and the second information should be readable in the first information section 110 and the second information section 70, respectively.
The hexagonal portion 32 is a portion exposed to the outer surface of the gas sensor 1 without being hidden even if the outer cylinder 25 and the protector 24 are attached in subsequent steps. Further, since the plane of the hexagonal portion 32 is not a curved surface like the outer cylinder 25 or the like, there is an advantage that the second information can be easily read by a camera or the like.

As described above, the first information section 110 storing the first information is attached to the outer surface of the sensor element 100, and the outer surface of the gas sensor 1 (or an external component integrated with the gas sensor) is provided with the first information. A second information section 70 is attached in which second information including at least a part is stored.
Therefore, even if the sensor element 100 is assembled to the gas sensor 1 and the first information section 110 is concealed, if the second information section 70 attached to the outer surface of the gas sensor 1 or an external component integral with the gas sensor 1 is read, the assembled The problem that the first information cannot be read after attachment is solved.
In particular, in the gas sensor 1 of this embodiment, the first information section 110 is hidden by the outer cylinder 25 welded to the metallic shell 30 . Therefore, in order to read the first information stored in the first information section 110 from the completed state of the gas sensor 1, the gas sensor 1 must be destroyed and the outer cylinder 25 must be removed. By attaching it, the first information can be read non-destructively even after the gas sensor 1 is assembled.

Moreover, since the second information includes at least a part of the first information of the individual sensor element, it is possible to prevent the sensor element 100 from being mixed up and attaching the wrong second information section 70 to another gas sensor 1 .
As a result, the information relating to the individual sensor element can be attached to the outer surface of the gas sensor or the external component integral with the gas sensor without error.

A method for manufacturing a gas sensor according to an embodiment of the present invention can be performed, for example, as described above. First, the first information section 110 is attached to the outer surface of the sensor element 100 (first information section providing step). Next, the first information is read (first information reading step). Then, the sensor element 100 is held on the metal shell 30 so that the first information part 110 is exposed (metal shell holding step).
Next, the outer periphery of the sensor element 110 including the first information portion 110 is covered with a case (the outer cylinder 25 and the protector 24 in this example) to assemble the gas sensor 1, and the first information read in the first information reading step is The second information including at least part of it is stored in the second information section 70 and attached to the outer surface of the gas sensor 1 or an external component integrated with the gas sensor 1 (second information section providing step).

Thus, if the first information is read before the sensor element 100 is assembled to the gas sensor 1 and the first information section 110 is hidden, and the second information section 70 is added based on the read first information. , the problem that the first information cannot be read after the gas sensor 1 is assembled is solved. In addition, it is possible to prevent the sensor element 100 from being mixed up and attaching the wrong second information part 70 to another gas sensor.
As a result, the information relating to the individual sensor element can be attached to the outer surface of the gas sensor or the external component integral with the gas sensor without error.

The metal shell holding step may be performed before the first information reading step, not just after the first information reading step.

The first information section 110 and the second information section 70 include symbols, character strings, numbers, bar codes, and the like, and printing methods include printing, laser engraving, and the like.
Further, the first information may be any information related to individual sensor elements, such as manufacturing information (element ID, manufacturing date, manufacturing lot, serial number) assigned to each individual sensor element 100 . .
The second information may include at least part of the first information. rank value, etc.).

FIG. 3 shows another embodiment in which the gas sensor 1 or external components 150, 180 integral with the gas sensor 1 are provided with the second information part.
Here, the term "external component integrated with the gas sensor" refers to a component that is coupled with the gas sensor and cannot be separated from the gas sensor. In the example of FIG. 3, the lead wires 11-15 (FIG. 1) drawn out from the gas sensor 1 are covered with a heat-resistant tube 150, and the rear ends of the lead wires 11-15 are connected to a male connector 180. These heat-resistant tube 150 and male connector 180 are connected to the gas sensor 1 and correspond to "external parts".
In the example of FIG. 3, as a mode of attaching the second information portion, for example, the second information portion 73 or 74 is attached to the outer surface of the outer cylinder 25 or the protector 24 forming the "case", respectively.
Also, the seal 80 with the second information part 72 attached can be wrapped around the heat-resistant tube 150 constituting the "external part" and attached, or the second information part 75 can be attached to the outer surface of the male connector 180. good.

The present invention is not limited to the above embodiments, and can be applied to, for example, a NOx sensor (NOx sensor element) that detects the NOx concentration in the gas to be measured, an HC sensor (HC sensor element) that detects the HC concentration, and the like. You may Moreover, the sensor element is not limited to a plate shape, and may be cylindrical.

Moreover, the second information may include at least a part of the first information, and may be the same information as the first information, or may be a part of the first information reduced. Further, when the second information has additional information in addition to the first information, the additional information is not limited to the above output characteristics information.
Further, when the second information does not have additional information in addition to the first information, the database 200 of FIG. A part of the read first information may be reduced to obtain the second information.

1 gas sensor 24 case (protector)
25 case (outer cylinder)
30 metal shell 32 hexagonal part 70, 72 to 75 second information part 100 sensor element 110 first information part 150, 180 external part

Claims (3)

a sensor element having, on its outer surface, a first information section storing first information that is information related to the individual sensor element;
a metal shell that holds the sensor element so that the first information part is exposed;
A gas sensor comprising a case joined to the metal shell while covering the outer periphery of the sensor element including the first information part,
a second information section storing second information including at least part of the first information is attached to the outer surface of the gas sensor or an external component integrated with the gas sensor ;
The gas sensor , wherein the first information includes manufacturing information of the sensor element, and the second information includes the first information and output characteristic information not included in the first information . 2. The gas sensor according to claim 1 , wherein the second information portion is attached to the plane of the hexagonal portion of the metallic shell. a first information portion attaching step of attaching, to the outer surface of the sensor element, a first information portion storing first information, which is information related to the individual sensor element;
a first information reading step of reading the first information;
a metal shell holding step of holding the sensor element on the metal shell so that the first information portion is exposed before or after the first information reading step;
After the metallic shell holding step, the outer periphery of the sensor element including the first information portion is covered with a case to assemble the gas sensor, and the first information reading step includes at least part of the first information read in the first information reading step. 2 information is stored in a second information section and attached to the outer surface of the gas sensor or an external component integrated with the gas sensor;
A method of manufacturing a gas sensor, comprising:

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