JP6650856B2 - Manufacturing method of gas sensor element - Google Patents

Description

  The present invention relates to a method for manufacturing a gas sensor element used for controlling combustion of an internal combustion engine.

2. Description of the Related Art There is known a gas sensor which is used by being attached to an exhaust pipe of an internal combustion engine of an automobile or the like and includes a gas sensor element for detecting the concentration of a specific gas such as oxygen in exhaust gas. Such a gas sensor includes a gas sensor element in which an inner electrode and an outer electrode are provided as a detection unit on the inner surface and the outer surface of an oxygen ion conductive bottomed cylindrical solid electrolyte body, respectively, according to the oxygen concentration in the gas to be detected. Some devices measure the electromotive force generated between both electrodes.
In addition, in order to protect the gas sensor element from water and soot in the gas to be detected, the outer surface of the detection section at the tip of the gas sensor element is immersed in a slurry in which ceramic particles are dispersed, dried and fired to form a porous body. Covering with a protective layer consisting of a layer is also performed.

By the way, when performing various processes such as immersing the gas sensor element provided with the inner electrode and the outer electrode in the slurry for the protective layer and drying the gas sensor element, the individual gas sensor elements are conveyed using a conveyor (crawler path). Conveyed to the post-process.
As a specific example of a method of transporting a cylindrical body in such a manufacturing process, a method is disclosed in which each cylindrical body is inserted and held in a pin planted on an individual conveyor piece (Patent Document 1).
When this method is used for a cylindrical gas sensor element, as shown in FIG. 3, after the tip of the gas sensor element 50 is immersed in the slurry of the dip tank 300, the gas sensor element 50 is turned upside down to lower the opening. The opening of the gas sensor element 50 is accommodated and conveyed to the pins 1000p projecting upward from the plurality of element conveying sections 1000 moving on the conveyor 102. After the gas sensor element 50 is conveyed to the drying furnace 106 by the conveyor 102 to dry the slurry, it is further conveyed to the next step Q.

JP-A-6-43105

  However, when the pin 1000p on the conveyor 102 is inserted and held in the opening of the gas sensor element 50 as in the technique described in Patent Document 1, the pin 1000p contacts the inner surface of the gas sensor element 50, and the gas sensor element 50 is damaged. Or the inner electrode may be scraped. In particular, the inner electrode is often formed by plating or the like, and since the plating thickness is thin, the inner electrode is easily shaved.

  That is, an object of the present invention is to provide a method for manufacturing a gas sensor element in which damage to an inner electrode is suppressed when the gas sensor element is held and transported.

Method for manufacturing a gas sensor element of the present invention carries the gas sensor element the inner electrodes formed on the inner surface of the bottomed tubular solid electrolyte body extending in the axial direction, in the manufacturing method of the gas sensor element for performing predetermined processing, the The gas sensor element has a straight portion having a constant outer diameter from the opening toward the bottom , and the inner diameter of the gas sensor element is larger than the outer diameter of the gas sensor element in a state where the opening of the gas sensor element faces downward. Inside the cylindrical holding portion, the gas sensor element is accommodated and transported, and the straight portion can be gripped by a gripper in a process after transporting the gas sensor element, so that the straight portion can be gripped from the upper end of the holding portion. The length L in the axial direction up to the upper end is longer than the length C in the axial direction of the gripper .
According to this method of manufacturing a gas sensor element, the gas sensor element is housed and transported inside the cylindrical holding section, so that the holding section does not contact the inner electrode on the inner surface of the gas sensor element. Can be suppressed.
Further, the straight portion having a constant outer diameter and easy to grip can be reliably gripped by the gripper.

In the method for manufacturing a gas sensor element according to the present invention, the holding portion may be made of a synthetic resin.
According to this method for manufacturing a gas sensor element, it is possible to prevent the gas sensor element from being damaged even when the gas sensor element contacts the edge of the holding portion.

In the method for manufacturing a gas sensor element according to the aspect of the invention, it is preferable that the predetermined process is a drying process, and a heat resistant temperature of the holding unit is higher than an ambient temperature in the drying process.
According to this method for manufacturing a gas sensor element, when the holding portion is made of synthetic resin, the heat resistance of the holding portion can be ensured by the drying process.

In the method for manufacturing a gas sensor element according to the present invention, a gap G between the holding portion and the gas sensor element may be 0.3 to 0.5 mm.
According to the method for manufacturing a gas sensor element, when the gas sensor element is housed in the holding section, the gas sensor element contacts the holding section and is damaged or cannot be housed in the holding section due to a shake of a chuck or the like holding the gas sensor element. Can be suppressed. In addition, it is possible to prevent the gas sensor element from being blurred in the holding section due to the gap G being too wide, and the gas sensor element from being unable to be held by the holding section.

In the method for manufacturing a gas sensor element according to the present invention, the holding section may be placed on a transport path, and the gas sensor element may be accommodated and transported while the holding section is positioned on the transport path.
According to this method for manufacturing a gas sensor element, thereby, it is possible to suppress the holding unit from being shifted from the supply position of the gas sensor element due to a shift of the transport path or the like, and the gas sensor element falls off without being stored in the holding unit, It is also possible to prevent the gas sensor element from contacting the edge of the holding portion and being damaged.

  According to the present invention, when holding and transporting the gas sensor element, damage to the inner electrode can be suppressed.

FIG. 5 is a view showing a mode in which the gas sensor element is accommodated in the holding unit and transported in the method for manufacturing the gas sensor element according to the embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating a mode in which a gas sensor element housed in a holding unit is gripped by a gripping tool. It is a figure showing the conventional transportation method of the gas sensor element.

Hereinafter, a method for manufacturing a gas sensor element according to an embodiment of the present invention will be described with reference to FIGS.
In the present embodiment, as an example of carrying the gas sensor element 50 and performing a predetermined process, the gas sensor element 50 is immersed in the slurry for the protective layer, and then carried to the drying furnace 106 on the conveyor (crawler path) 102. The drying process is exemplified, but the drying process is not limited to this.
First, in FIG. 1, the rear end (opening side) of a cylindrical (cup-shaped) gas sensor element 50 is gripped by a jig 302, and the tip end (bottom part) of the gas sensor element 50 is placed in a dip tank 300 storing slurry. ) To form a slurry film. Next, the jig 302 is turned upside down so that the front end of the gas sensor element 50 faces upward and the opening at the rear end faces downward, and is conveyed to the drying furnace 106.

As shown in FIG. 2, the gas sensor element 50 has an inner electrode 51 and an outer electrode 53 formed on an inner surface and an outer surface of a bottomed solid electrolyte body extending in the direction of the axis O, respectively.
Further, the gas sensor element 50 includes a straight portion 55 having a constant outer diameter from the opening (lower side in FIG. 2) to the bottom (upper side in FIG. 2), and a flange portion 57 is provided on the bottom side of the straight portion 55. Is provided. The flange 57 engages with a step on the inner surface of the metal shell and is assembled as a gas sensor.

Returning to FIG. 1, a plurality of element transport units 110 are placed on a conveyor (crawler path) 102 having an oblong track, and the element transport units 110 are transported to the conveyor 102 without being fixed. It has become. Specifically, an elliptical guide 104 is provided upright along the inner periphery of the conveyor 102, and the element conveying unit 110 is pressed toward the guide 104 on the conveyor 102 by a pressing jig 220. The element transport section 110 can be positioned at a predetermined position on the conveyor 102 (a supply position P described later).
The pressing jig 220 has a bifurcated (Y-shaped) branch portion 222. Then, while holding the holding portion 114 on the inner surface of the branch portion 222, the holding portion 114 is pressed against the arc-shaped portion of the guide 104 and positioned at the supply position P.

The element transport section 110 has a substantially rectangular base 112 and a cylindrical holder 114 mounted on the base 112. The inner diameter of the holding part 114 is larger than the outer diameter of the gas sensor element 50, and the gas sensor element 50 is accommodated and held inside the holding part 114 with the opening of the gas sensor element 50 facing downward. (See FIG. 2).
The gas sensor element 50 is sequentially supplied from the supply position P on the conveyor 102 with the opening of the gas sensor element 50 facing down, and the holding unit of the element transfer unit 110 positioned and arranged on the conveyor 102 at the supply position P. After being accommodated in 114, the element transport section 110 is transported along the conveyor 102 to the inside of the drying furnace 106, and the slurry film is dried.
Thereafter, the gas sensor element 50 is carried out of the drying furnace 106 at the carry-out position Q, and moves to the next step. The empty element transport section 110 from which the gas sensor element 50 has been removed returns to the supply position P in sequence.

As described above, according to the present invention, since the gas sensor element 50 is accommodated and transported inside the cylindrical holding section 114, the holding section 114 does not contact the inner electrode 51 on the inner surface of the gas sensor element 50. The inner electrode 51 can be prevented from being scraped.
Note that the outer electrode 53 on the outer surface of the gas sensor element 50 may come into contact with the inner surface of the holder 114, but the outer electrode 53 is generally thicker than the inner electrode 51 because it is formed by printing or the like. However, the outer electrode 53 is hard to scrape.

  In the present embodiment, the gas sensor element 50 is housed inside the holding unit 114 after the (the holding unit 114 of) the element conveying unit 110 is positioned at the supply position P. Accordingly, the holding portion 114 is prevented from being shifted from the supply position P due to the shift of the conveyor 102 or the like. It can also be prevented from being damaged by contact with the surface.

As shown in FIG. 2, in the present embodiment, after the gas sensor element 50 is gripped by the gripper 70 at the carry-out position Q and carried out, the tip of the gas sensor element 50 faces downward and the opening faces upward. The slurry is held upside down by the jig 302 and immersed again in the dip tank 300 to increase the thickness of the slurry film. Then, after re-drying, in a later step, baking treatment or the like of the electrode and the slurry film is performed.
Here, the length L in the axis O direction from the upper end of the holding portion 114 to the upper end of the straight portion 55 is longer than the length C of the gripper 70 in the axis O direction. Thus, the straight portion 55 having a constant outer diameter and easy to grip can be reliably gripped by the gripper 70.

Further, when the holding section 114 is made of a synthetic resin, it is possible to prevent the gas sensor element 50 from being damaged even if the gas sensor element 50 contacts the edge of the holding section 114. When the holding section 114 is made of a synthetic resin, it is necessary that the heat resistant temperature of the holding section 114 be higher than the ambient temperature of the drying furnace 106 in the drying process.
Examples of the synthetic resin used for the holding unit 114 include PEEK (polyether ether ketone).

It is preferable that the gap G between the holding portion 114 and the gas sensor element 50 is 0.3 to 0.5 mm. When the gap G is less than 0.3 mm, when the gas sensor element 50 is housed in the holding unit 114, the gas sensor element 50 comes into contact with the holding unit 114 and is damaged by a shake of a chuck or the like holding the gas sensor element 50, It may be difficult to accommodate the holder 114.
If the gap G exceeds 0.5 mm, the gas sensor element 50 may be blurred in the holding unit 114, and it may be difficult to grip the gas sensor element 50 with the grip unit 70.

  The present invention is not limited to the above-described embodiment, but extends to various modifications and equivalents included in the spirit and scope of the present invention.

Reference Signs List 50 gas sensor element 51 inner electrode 55 straight part 70 gripper 102 transport path (conveyor)
114 Holder O axis

Claims (5)

In a method for manufacturing a gas sensor element in which a gas sensor element in which an inner electrode is formed on an inner surface of a bottomed cylindrical solid electrolyte body extending in an axial direction and a predetermined process is performed,
The gas sensor element includes a straight portion having a constant outer diameter from the opening toward the bottom,
With the opening of the gas sensor element facing downward, the inner diameter of the gas sensor element is accommodated and transported inside a cylindrical holding portion having a larger diameter than the outer diameter of the gas sensor element ,
The length L in the axial direction from the upper end of the holding portion to the upper end of the straight portion is set in the axial direction of the gripper so that the straight portion can be gripped by the gripper in a process after transporting the gas sensor element. A method for manufacturing a gas sensor element, wherein the length is longer than the length C of the gas sensor element. 2. The method according to claim 1, wherein the holding portion is made of a synthetic resin . 3. The method according to claim 1, wherein the predetermined process is a drying process, and a heat-resistant temperature of the holding unit is higher than an ambient temperature in the drying process . The method for manufacturing a gas sensor element according to any one of claims 1 to 3, wherein a gap G between the holding portion and the gas sensor element is 0.3 to 0.5 mm . The gas sensor element according to any one of claims 1 to 4 , wherein the holding unit is placed on a transport path, and the gas sensor element is accommodated and transported while the holding unit is positioned on the transport path. Manufacturing method.

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