JP2018063188A - Gas sensor manufacturing method and gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a gas sensor in which a display part attached to each sensor element can reliably be read irrespective of size reduction of the sensor element, and the gas sensor.SOLUTION: There is provided a manufacturing method of a gas sensor for reading a display part 40 attached to a surface of a sensor element 100 and including information on the sensor element. The sensor element has a tip side and a rear end side which protrude from a tip and a rear end of a main body metal fitting 30. A cylindrical insulation holder 39 fixed by a caulking part 30a formed by inwardly bending the rear end part of the main body metal fitting is arranged between the sensor element and the main body metal fitting. A read end facing surface of the insulation holder is positioned closer to the tip than the rear end of the caulking part. At least a part of the display part is attached to the surface of the sensor element between the caulking part and the insulation holder. The display part is read from a direction which intersects with an axial line O of the sensor element and from which the entire display part between the caulking part and the insulation holder can visually be recognised.SELECTED DRAWING: Figure 2

Description

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

  Conventionally, a gas sensor for detecting the concentration of a specific component (oxygen or the like) in exhaust gas of an internal combustion engine has been used. As shown in FIG. 3, this gas sensor is manufactured by arranging an outer cylinder, a terminal fitting, and the like (not shown) on an intermediate product 1000 x in which a sensor element 1000 extending in the direction of the axis O is assembled to the metal shell 30. The sensor element 1000 includes a detection unit 1000a having a solid electrolyte body and a pair of electrodes arranged on the solid electrolyte body, and a gas to be detected by a controller (not shown) connected to a terminal fitting of the gas sensor via a lead wire. The electromotive force generated between both electrodes is measured according to the oxygen concentration in the medium.

By the way, each electrode is generally formed by baking after printing a metal paste, so that the thickness and dimensions of the electrode slightly vary for each sensor element 1000, and sensor characteristics such as electromotive force generated between both electrodes also slightly vary. To do. For this reason, sensor characteristics are measured for each individual sensor element 1000, and the information is printed on the element with symbols, character strings, and the like. And when connecting a controller to the gas sensor which assembled this sensor element 1000, this sensor information is read and calibration (output value amendment and rank amendment) of a controller is performed.
As described above, in the production process, information such as characteristics and product types for each intermediate product is printed and read by a CCD camera or the like to manage the process (see Patent Document 1).

Japanese Patent Laid-Open No. 2000-67785 (FIG. 7)

As shown in FIG. 3, in the intermediate product 1000 x, the periphery of the sensor element 1000 is covered with the metal shell 30, and the detection unit 1000 a on the tip side of the sensor element 1000 is covered with the protector 24. Further, electrode pads 1210 and 1220 connected to the terminal fittings are formed on the rear end side of the sensor element 1000.
Therefore, the sensor information printing part 400 is provided on the surface of the sensor element 1000 between the electrode pads 1210 and 1220 and the insulating holder 300 that protrudes from the crimping part 30a on the rear end side of the metal shell 30 and surrounds the sensor element 1000. Provided. Then, the printing unit 400 is read from the horizontal direction by the CCD camera 500.

However, in order to reduce the size and cost of the gas sensor, it is desired to shorten the entire length of the sensor element 1000, and there is a problem that a space that can be used as the printing unit 400 is limited. On the other hand, in order to read the printing unit 400 accurately, a certain size of the printing unit 400 is required.
Accordingly, an object of the present invention is to provide a gas sensor manufacturing method and a gas sensor that can reliably read a display portion attached to each sensor element even if the sensor element is downsized.

  In order to solve the above-mentioned problems, a gas sensor manufacturing method according to the present invention is a gas sensor manufacturing method for reading a display unit that is attached to the surface of a sensor element extending in the axial direction and includes information related to the sensor element. Is inserted through the inside of the cylindrical metal shell, its front end side and rear end side protrude from the front end and rear end of the metal shell, respectively, and between the sensor element and the metal shell, A cylindrical insulating holder that is fixed in a state of being pressed from the rear end side toward the front end side by a caulking portion formed by bending the rear end portion inward is disposed, and the rear end facing surface of the insulating holder is It is located on the front end side from the rear end of the crimped portion, and at least a part of the display unit is attached to the surface of the sensor element between the crimped portion and the insulating holder, Sen A direction crossing the axis of the element, characterized in that reading the said display unit in a direction which is entirely visible in the display portion between the insulating holder and the caulking portion.

According to this method of manufacturing a gas sensor, the rear end-facing surface of the insulating holder is located on the front end side of the rear end of the crimped portion, so the sensor between the crimped portion and the rear end facing surface of the insulating holder. By attaching at least part of the display portion to the surface of the element, a space that can be used as the display portion can be secured, and the display portion can be reliably read with a certain size. In this way, the sensor element can be shortened by the amount that can secure the space for the display unit, and the gas sensor can be reduced in size and cost. In addition, the sensor element is shortened, so that the warpage is reduced and the display unit is read by the warp. Errors can also be suppressed.
Then, by reading the display unit from the direction that intersects the axis and from which the entire display unit between the crimping unit and the insulating holder is visible, the display unit is not hidden as a shadow of the crimping unit. Since all the display portions appear in the direction, the information on all the display portions can be read reliably.

In the gas sensor manufacturing method of the present invention, an electrode pad is formed on the surface of the sensor element on the rear end side with respect to the caulking portion, and the display portion includes the sensor element between the electrode pad and the insulating holder. It may be attached to the surface.
According to this method of manufacturing a gas sensor, it is possible to effectively use a space that can be used as a display unit among sensor elements.

The gas sensor of the present invention includes a cylindrical metal shell, and a sensor element that extends in the axial direction and is inserted and disposed inside the metal shell, and the front end side and the rear end side thereof protrude from the front end and the rear end of the metal shell, respectively. And a cylindrical insulating holder disposed between the sensor element and the metallic shell, wherein the rear end portion of the metallic shell is bent inward, and a caulking portion is bent from the rear end side to the distal end side. A cylindrical insulating holder that is fixed in a pressed state toward the rear side, and the rear end facing surface of the insulating holder is located on the front end side with respect to the rear end of the crimped portion, and At least a part of a display unit including information on the sensor element is attached to the surface of the sensor element between the fastening part and the insulating holder.
According to this gas sensor, since the rear end facing surface of the insulating holder is located on the front end side of the rear end of the crimping portion, the surface of the sensor element between the crimping portion and the rear end facing surface of the insulating holder By attaching at least a part of the display unit to the space, a space that can be used as the display unit can be secured, and the display unit can be reliably read with a certain size. As described above, the sensor element can be shortened by the amount that can secure the space for the display unit, and the gas sensor can be reduced in size and cost. Errors can also be suppressed.

In the gas sensor of the present invention, an electrode pad is formed on the surface of the sensor element on the rear end side of the caulking part, and the display part is formed on the surface of the sensor element between the electrode pad and the insulating holder. It may be attached.
According to this gas sensor, the space which can be used as a display part among sensor elements can be used effectively.

  According to this invention, even if a sensor element is reduced in size, the gas sensor which can read the display part provided for every sensor element reliably is obtained.

It is sectional drawing which follows the axial direction of the gas sensor (oxygen sensor) which concerns on embodiment of this invention. It is a fragmentary sectional view which shows the aspect which reads the intermediate product of a gas sensor, and its display part. It is a fragmentary sectional view which shows the aspect which reads the intermediate product of the conventional gas sensor, and its printing part.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a sectional view taken along the direction of the axis O of a gas sensor (oxygen sensor) 1 according to an embodiment of the present invention, and FIG. 2 is a partial sectional view of an intermediate product 1x of the gas sensor 1.

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 cylindrical metal shell 30 that holds the sensor element 100 inserted and disposed inside itself, and a distal end portion of the metal shell 30. And a protector 24 and the like to be attached to the housing.
The sensor element 100 includes a detection unit 100a having a solid electrolyte body and a pair of electrodes arranged on the solid electrolyte body on the front end side, and electrode pads 121 and 122 on the rear end side.

The metal shell 30 is made of SUS430, and has a male screw portion 31 for attaching the gas sensor to the exhaust pipe, and a hexagonal portion 32 to which an attachment tool is applied at the time of attachment. Further, the metal shell 30 is provided with a metal side step portion 33 protruding radially inward, and this metal side step portion 33 supports a metal holder 34 for holding the sensor element 100. . Inside the metal holder 34, a ceramic holder 35, a first talc 37, and a second talc 38 are arranged in this order from the tip side.
The sensor element 100 is fixed to the metal holder 34 by compressing and filling the first talc 37 in the metal holder 34. Further, the second talc 38 is compressed and filled in the metal shell 30, so that a sealing property between the surface of the sensor element 100 and the inner surface of the metal shell 30 is ensured. An alumina sleeve (insulating holder) 39 is disposed on the rear end side of the second talc 38. The sleeve 39 is formed in a cylindrical shape with a flat rear end surface, and is provided with a shaft hole 39a along the axis O, and the sensor element 100 is inserted therein. The caulking portion 30 a on the rear end side of the metal shell 30 is bent inward, and the sleeve 39 is pressed to the front end side of the metal shell 30 through a stainless steel ring member 55.

  Further, a metal protector 24 having a plurality of gas intake holes is attached to the outer periphery on the front end side of the metallic shell 30 by covering the distal end portion of the sensor element 100 protruding from the distal end of the metallic shell 30 by welding. The protector 24 has a double structure, and has a bottomed cylindrical outer protector 41 having a uniform outer diameter on the outer side, and a bottomed cylindrical inner protector 42 having a smaller diameter than the outer protector 41 on the inner side. Is arranged.

  On the other hand, on the rear end side of the metal shell 30, the front end side of the outer tube 25 made of SUS430 is inserted. The outer cylinder 25 has a distal end portion 25a whose diameter is enlarged on the distal end side fixed to the metal shell 30 by laser welding or the like. A separator 50 is disposed inside the rear end side of the outer cylinder 25, and a holding member 51 is interposed in a gap between the separator 50 and the outer cylinder 25. The holding member 51 is fixed by the outer cylinder 25 and the separator 50 by engaging the flange 50 a of the separator 50 and caulking the outer cylinder 25.

  Further, the separator 50 is provided with an insertion hole 50b for inserting the lead wires 11 to 15 from the front end side to the rear end side (note that the lead wires 14 and 15 are not shown). The connection terminal 16 that connects the lead wires 11 to 15 and the electrode pads 121 and 122 is accommodated in the insertion hole 50b. Each lead wire 11-15 is connected to a connector (not shown) outside. An electrical signal is input and output between a controller (external device) such as an ECU and the lead wires 11 to 15 via this connector. Moreover, although not shown in detail in each lead wire 11-15, it has the structure which showed the conducting wire with the insulating film which consists of resin.

  Further, a substantially cylindrical rubber cap 52 for closing the opening 25 b on the rear end side of the outer cylinder 25 is disposed on the rear end side of the separator 50. The rubber cap 52 is fixed to the outer cylinder 25 by caulking the outer periphery of the outer cylinder 25 toward the radially inner side in a state where the rubber cap 52 is mounted in 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 from the front end side to the rear end side.

Next, the sleeve 39 and the display unit 40 that are characteristic parts of the gas sensor 1 of the present invention will be described. As shown in FIG. 2, in the intermediate product 1 x, the sleeve 39 is pressed to the front end side via the ring member 55 by the caulking portion 30 a on the rear end side of the metal shell 30. Here, since the rear end-facing surface 39e of the sleeve 39 is flat, the rear end-facing surface 39e of the sleeve 39 is more distal than the rear end of the caulking portion 30a by the thickness of the caulking portion 30a and the ring member 55. Located on the side.
Therefore, for example, compared with the conventional sensor element 1000 in FIG. 3 (broken line on the element rear end side in FIG. 2), even if the length of the sensor element 100 of the present embodiment in the direction of the axis O is shortened, The surface of the sensor element 100 between the rear end facing surface 39e of the sleeve 39 can be exposed.

For this reason, by attaching at least a part of the display unit 40 to the surface of the sensor element 100 between the crimping unit 30a and the rear end facing surface 39e of the sleeve 39, a space that can be used as the display unit 40 is secured and displayed. The display unit 40 can be reliably read by setting the unit 40 to a certain size.
When the sensor element 100 is shortened, the gas sensor 1 can be reduced in size and cost, and the sensor element 100 is shortened, so that the warpage is reduced and the reading error of the display unit 40 due to the warpage can be suppressed.

  Examples of the display unit 40 include symbols, character strings, numbers, barcodes, and the like, and the printing method includes printing, laser marking, and the like. The information included in the display unit 40 may be information related to each sensor element 100. For example, the display unit 40 corresponds to sensor output characteristics such as electromotive force for each sensor element 100, sensor type, and output characteristics. Rank value.

In the gas sensor manufacturing method according to the embodiment of the present invention, the direction R intersects the axis O at the angle θ, and the direction R in which the entire display unit 40 between the crimped portion 30a and the sleeve 39 can be visually recognized. The display unit 40 is read by the CCD camera 500 or the like.
Thereby, since all the display parts 40 appear in the direction R which the display part 40 becomes a shadow of the crimping part 30a and is not hidden, the information of all these display parts 40 can be read reliably.
And after reading the information of the display part 40, when connecting a controller to the gas sensor which assembled this sensor element 100, calibration (output value correction | amendment and rank correction | amendment) of a controller should just be performed based on this sensor information.

  In the present embodiment, the display unit 40 is attached to the surface of the sensor element 100 between the electrode pad 122 on the front end side and the rear end facing surface 39e of the sleeve 39. Thereby, the space which can be utilized as the display part 40 among the sensor elements 100 can be used effectively.

The present invention is not limited to the above-described embodiment. For example, the present invention is applied to a NOx sensor (NOx sensor element) that detects NOx concentration in a gas to be measured, an HC sensor (HC sensor element) that detects HC concentration, and the like. May be. The sensor element is not limited to a plate shape, and may be a cylinder shape.
The display unit 40 and the CCD camera 500 only need to intersect with the axis O relatively. For example, the intermediate product 1x including the sensor element 100 may be conveyed in the horizontal direction so that the optical axis of the CCD camera 500 is at an angle θ with respect to the axis O, and the optical axis of the CCD camera 500 is horizontal and includes the sensor element 100. The product 1x may be transported in an inclined state with respect to the axis O at an angle θ.

DESCRIPTION OF SYMBOLS 1 Gas sensor 30 Metal fitting 30a Clamping part 39 Insulation holder (sleeve)
39a Rear end-facing surface of insulating holder 40 Display unit 100 Sensor element 121, 122 Electrode pad O Axis line R A direction intersecting the axis line

Claims (4)

A method for manufacturing a gas sensor, which is attached to a surface of a sensor element extending in an axial direction and reads a display unit including information on the sensor element,
The sensor element is inserted and arranged inside the cylindrical metal shell, and its front end side and rear end side protrude from the front end and rear end of the metal shell, respectively.
A cylinder fixed between the sensor element and the metal shell in a state of being pressed from the rear end side toward the front end side by a caulking portion formed by bending a rear end portion of the metal shell inward. In the shape of an insulating holder,
The rear end facing surface of the insulating holder is located on the front end side of the rear end of the crimped portion,
At least a part of the display part is attached to the surface of the sensor element between the crimped part and the insulating holder,
A method of manufacturing a gas sensor, comprising: reading the display unit from a direction that intersects the axis of the sensor element and from which the entire display unit between the caulking unit and the insulating holder is visible. .   An electrode pad is formed on the surface of the sensor element on the rear end side with respect to the caulking part, and the display part is attached to the surface of the sensor element between the electrode pad and the insulating holder. The method of manufacturing a gas sensor according to claim 1, wherein A cylindrical metal shell,
A sensor element that extends in the axial direction and is inserted and arranged inside the metal shell, and whose front end side and rear end side protrude from the front end and rear end of the metal shell, respectively.
A cylindrical insulating holder disposed between the sensor element and the metallic shell, wherein the rear end portion of the metallic shell is bent inward and is directed from the rear end side to the distal end side. A cylindrical insulating holder fixed in a pressed state,
The rear end facing surface of the insulating holder is located on the front end side of the rear end of the crimped portion,
A gas sensor, wherein at least a part of a display unit including information relating to the sensor element is attached to a surface of the sensor element between the crimping part and the insulating holder.   An electrode pad is formed on the surface of the sensor element on the rear end side with respect to the caulking part, and the display part is attached to the surface of the sensor element between the electrode pad and the insulating holder. The gas sensor according to claim 3, wherein

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