JP7259770B2 - Dip device - Google Patents

Description

The present invention relates to a dipping device for immersing a work in slurry and applying a slurry film to a predetermined portion of the work.

2. Description of the Related Art Conventionally, there has been known a dipping device for applying slurry to a gas sensor element used for combustion control of an internal combustion engine. A gas sensor element as a work has a cylindrical solid electrolyte body with a reference gas chamber inside, electrodes are provided on the inner and outer surfaces thereof, and the outer electrode is covered with a porous layer. When manufacturing the gas sensor element, the gas sensor element is immersed in slurry in a dip bath, the slurry is applied to a predetermined area of the element, and the slurry film having a predetermined thickness is baked to form a porous layer.

Patent Document 1 proposes a method of attaching a plurality of solid electrolyte bodies to a jig and immersing them in the slurry in a dip bath at the same time in order to efficiently apply slurry to a plurality of gas sensor elements. In addition, in Patent Document 2, in order to apply a slurry film uniformly, the slurry is stirred with a stirring blade provided at the bottom of a dipping tank, and while applying vibration to the slurry through the dipping tank, a gas sensor element is applied to the slurry. The technique of soaking in is described.

JP-A-2002-323471 Japanese Patent Application Laid-Open No. 2017-161342

However, the conventional dipping device is in an environment where the temperature around the dipping tank tends to vary and the humidity tends to change along with the temperature. Therefore, when the temperature of the slurry rises, the humidity around the dipping tank decreases, the slurry tends to dry up, and the free water surface of the slurry becomes unstable. If the gas sensor element is immersed in such a state, the slurry cannot be applied to the specified range, or the application amount varies due to non-uniform slurry concentration. As a result, when the coating weight was measured, there was a tendency to produce defective products whose measured values did not meet the standard values.

In order to stabilize the free water surface of the slurry, a method of blowing air whose temperature has been controlled in advance around the dip tank can be considered. However, according to this method, there is a possibility that the free water surface of the slurry may be undulated due to air blowing, the coating amount may vary, or the surrounding dust may be mixed. Similarly, when the slurry in the dipping tank is agitated, the free water surface of the slurry becomes turbulent, resulting in a longer waiting time until a calm state is reached, resulting in an increase in the cycle time of the dipping device.

Moreover, the slurry in which the gas sensor element is immersed is made of a powdery porous material, and precipitates or agglomerates easily at an early stage. For this reason, conventionally, at least once a day, a worker manually carries the dipping tank out of the apparatus, takes out the used slurry from the dipping tank, cleans the inside of the tank, and then puts in new slurry and dips. It was necessary to manually push the bath back into the apparatus. Therefore, the maintenance work of the dip bath takes time, which is also a factor in extending the cycle time.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a dipping apparatus capable of applying a slurry film to a workpiece with a uniform thickness. Another object of the present invention is to provide a dipping device that facilitates maintenance work of the dipping bath.

In order to solve the above problems, the dipping device (10) of the present invention comprises a dipping tank (13) for storing the slurry (2) and a liquid level sensor (19) for detecting the height of the liquid level (200) of the slurry. ), a loader (18) that ascends and descends with a stroke corresponding to the height of the liquid surface to immerse the workpiece in the slurry, a temperature and humidity chamber (14) that forms a temperature and humidity control chamber around the dipping chamber, and a temperature and humidity chamber. A shutter (36) that can open and close the liquid surface of the slurry from above, a stirring blade (20) that stirs the slurry in the dipping tank, a motor (32) that rotates the stirring blade, and when the dipping tank moves and a clutch (34) for disconnecting the stirring blade from the motor. When the shutter is closed, a moisturizing space (25) is formed between the shutter and the liquid surface of the slurry, and the temperature and humidity control chamber communicates with the moisturizing space. ing. In order to facilitate the maintenance work of the dipping tank, the dipping tank is provided so as to be movable into and out of the temperature/humidity control room from the entrance/exit (27) of the temperature/humidity tank.

In one embodiment of the dipping device , the dipping tank is further provided with a lid member, and when the dipping tank is positioned inside the temperature/humidity controlled chamber, the lid member closes the doorway of the temperature/humidity tank. In this way, when the shutter is closed, the airtightness of the temperature/humidity control room and the moisturizing space can be improved.

In addition, in order to dynamically manage the temperature and humidity of the moisturizing space, the dipping device of one embodiment includes a control air generator (23) that generates control air whose temperature and humidity are controlled, and a and a piping member (22) for circulation to the humidity control room. In this case, it is desirable to supply the control air as a gentle stream to the dipping tank so that the liquid surface of the slurry is not turbulent due to the blowing air. Specifically, an intermediate plate (42) is provided on the upper surface of the temperature/humidity bath, and the temperature/humidity control chamber is communicated with the moisturizing space through small holes (44) formed in the intermediate plate.

According to the dipping device of the present invention, when the work is dipped in the slurry, the shutter opens the liquid surface of the slurry and the liquid surface sensor detects the height of the liquid surface. Then, the loader moves up and down with a stroke corresponding to the height of the liquid surface, and the work is immersed in the slurry at an accurate depth to apply the slurry to a predetermined range. When the workpiece is lifted out of the slurry, the shutter closes, and the temperature and humidity control chamber around the dip tank communicates with the moisturizing space. Therefore, during the period in which the slurry is not applied, drying of the slurry can be prevented, the liquid surface can be maintained in a stable state, and a slurry film having a uniform thickness can be formed on the workpiece in the next application step.

1 is a general schematic diagram of a dipping apparatus showing one embodiment of the present invention; FIG. FIG. 3 is a cross-sectional view illustrating a gas sensor element as a work; A setter that is a jig for a gas sensor element is shown, (a) is a plan view of the setter, and (b) is a cross-sectional view of the setter. It is a cross-sectional view of a dipping device showing a dipping tank and a temperature/humidity tank. FIG. 4 is a plan view showing the dipping device with the shutter open; FIG. 4 is a side cross-sectional view showing the dipping device with the shutter closed; 4 is a flow chart showing a slurry coating method. It is a detailed view of the dipping step in the coating method.

(one embodiment)
An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a dipping device 10 that applies a slurry 2 to a gas sensor element 1 as a work. A dipping tank 13 and a temperature/humidity tank 14 are installed on a base 11 of the dipping device 10, and a column 15 is erected. An arm 16 is supported on the column 15 so as to move up and down along a rail 17 of the column 15 . The arm 16 is provided with a loader 18 for immersing the gas sensor element 1 in the slurry 2 and a liquid level sensor 19 consisting of a reflective laser sensor for detecting the height of the liquid level 200 of the slurry 2 .

The slurry 2 is an aqueous solution with a predetermined viscosity containing a powdery porous material as a main component, and is stored inside the dip tank 13 . A stirring blade 20 for stirring the slurry 2 is provided at the bottom of the dip tank 13 . The dip tank 13 is accommodated inside the temperature/humidity tank 14 , and the temperature/humidity control room 21 is formed around the dip tank 13 by the temperature/humidity tank 14 . The temperature/humidity control room 21 is connected to a control air generator 23 via a circulation pipe 22 . Control air generator 23 generates control air CA controlled to a predetermined temperature and humidity, and circulation pipe 22 circulates control air CA to temperature/humidity control chamber 21 .

As shown in FIG. 2, the gas sensor element 1 is composed of a cylindrical solid electrolyte body with one end closed, and has a predetermined range on the outer surface, that is, a range from the lower end to a predetermined height H in the figure (hereinafter referred to as coating range H ) is formed with a predetermined thickness. In the step of applying the slurry 2 , the plurality of gas sensor elements 1 are immersed in the slurry 2 in the dip tank 13 while being supported by the ceramic setter 4 . As shown in FIGS. 3A and 3B, the setter 4 is formed with a plurality of support holes 5 for inserting and supporting the gas sensor element 1, and the loader 18 is provided with a plurality of grips for releasably gripping the setter 4. A pawl 24 is provided.

As shown in FIGS. 4, 5, and 6, the dipping tank 13 is installed so as to be able to be pulled out in the lateral direction (direction of arrow X in FIG. 5) by means of a ball guide 26. As shown in FIG. The ball guide 26 is provided substantially horizontally on the base 11 , and the operator M moves the dip tank 13 to a dipping position inside the temperature/humidity control room 21 and a maintenance position outside the temperature/humidity control room 21 . A lid member 28 is provided on the front surface of the dipping tank 13, and a handle 29 to be gripped by the operator M is attached to the lid member 28. - 特許庁Then, when the dipping tank 13 is arranged at the dipping position, the cover member 28 closes the doorway 27 (see FIG. 6) of the temperature/humidity control chamber 21 .

A motor 32 (see FIG. 4) that rotates the stirring blades 20 is fixedly installed on the base 11 . A rotation transmission member 33 for transmitting the rotation of the motor 32 to the stirring blade 20 and a cover 35 are attached to the lower surface of the dip tank 13 . A clutch 34 is interposed between the rotation transmitting member 33 and the motor 32, and its meshing portion is protected by a cover 35. As shown in FIG. The clutch 34 connects the stirring blades 20 to the motor 32 when the dipping tank 13 is placed at the dipping position (see FIG. 1), and connects the stirring blades 20 when the dipping tank 13 moves to the maintenance position or the dipping position. 20 from the motor 32 (see FIG. 4).

A shutter 36 is provided above the dip tank 13 and the temperature/humidity tank 14 to cover the liquid surface 200 of the slurry 2 in an openable and closable manner. The shutter 36 is supported by a frame 38 erected on the base 11 via a linear guide 37 so as to be movable in the same direction as the dip tank 13 (X direction). A fluid pressure cylinder 39 is provided at the upper end of the frame 38, and the shutter 36 is moved by the fluid pressure cylinder 39 to a closed position (see FIG. 6) that covers the liquid surface 200 of the slurry 2 and an open position that opens the liquid surface 200 (see FIG. 6). 5).

When the shutter 36 is arranged at the closed position, a substantially closed moisturizing space 25 is formed between the shutter 36 and the liquid surface 200 of the slurry 2 . On the other hand, an intermediate plate 42 is attached to the upper surface of the temperature/humidity bath 14, and an opening 43 having the same size as the upper end open portion 130 (see FIG. 6) of the dipping bath 13 is formed in the intermediate plate 42. A plurality of small holes 44 (see FIG. 5) are formed in the intermediate plate 42 around the opening 43 , and the moisturizing space 25 communicates with the temperature/humidity control chamber 21 through the small holes 44 . Then, the controlled air CA in the temperature/humidity control chamber 21 is dispersed by the small holes 44, becomes a slow air current, flows into the moisturizing space 25, and is supplied from the moisturizing space 25 through the opening 43 into the dip tank 13. be.

A receiving pan 40 for receiving the gas sensor element 1 dropped from the setter 4 during transportation by the loader 18 is installed on the upper surface of the shutter 36, and a buffer sheet 45 is laid on the inner bottom surface. The shutter 36 is provided with a material inlet 41 and a door 46 for opening and closing the material inlet 41. With the shutter 36 positioned at the closed position, the powdery porous material, which is the slurry constituent material, is dipped. The slurry 2 in the tank 13 can be replenished.

An intake duct 47 and an exhaust duct 48 are provided at two opposing positions on the outer surface of the temperature/humidity chamber 14 . As shown in FIG. 1 , the control air CA generated by the control air generator 23 circulates to the temperature/humidity control chamber 21 through piping members including the circulation pipe 22 and ducts 47 and 48 . The control air generation unit 23 is provided with a heating unit 49 that heats the control air CA returned from the temperature/humidity control chamber 21, a humidification unit 50 that humidifies the air whose temperature has risen, and a blower 51. A controlled air CA is generated which is controlled within a temperature and humidity range (eg, temperature 25±5° C., humidity 62-68 RH).

Next, a method for applying the slurry 2 will be described. As shown in FIG. 7, first, a plurality of gas sensor elements 1 are set in the setter 4 (S1), and the setter 4 is mounted on the loader . Next, the shutter 36 is opened to open the upper surfaces of the dip tank 13 and the temperature/humidity tank 14 (S2). Subsequently, the loader 18 is lowered to immerse the gas sensor element 1 in the slurry 2 (S3). In this state, a slurry film 3 having a predetermined thickness is formed on a predetermined portion of the gas sensor element 1 over a predetermined time (S4). After that, the loader 18 is raised to the original position (S5), the shutter 36 is closed (S6), and the gas sensor element 1 is transported to the next process together with the setter 4 (S7).

In the coating step (S4) for forming the slurry film 3, the coating range of the gas sensor element 1 and the thickness of the slurry film 3 are controlled by the procedure (S41 to S46) shown in FIG. In step (S41), the liquid level sensor 19 detects the liquid level 200, which is the free water level of the slurry 2, and the controller 12 (see FIG. 1) feedback-controls the elevation of the loader 18 based on the detected value. In step (S42), the loader 18 descends at a constant speed and pauses just before the lower end of the gas sensor element 1 touches the liquid surface 200, and the immersion start time is set. Alternatively, the immersion start time is set without the loader 18 stopping just before the liquid surface.

In step (S43), the loader 18 resumes its descent, stops after a predetermined time has passed, and places the gas sensor element 1 at a position where the coating range H is immersed in the slurry 2. FIG. In step (S44), the immersion time is counted, and when a predetermined time has elapsed, the loader 18 is instantaneously raised, the gas sensor element 1 is slightly pulled up, and then stopped. After the waiting time for calming the liquid surface 200 has elapsed, the loader 18 rises at a constant speed in step (S45) and pauses at the liquid drain start position where the lower end of the gas sensor element 1 is slightly immersed in the liquid surface 200. In the procedure (S46), when the predetermined liquid draining time has elapsed, the loader 18 rises to the immersion completion position and stops, or conveys the gas sensor element 1 to the next step without stopping.

According to the dipping device 10 of the present embodiment, with the shutter 36 open, the loader 18 moves up and down with a stroke corresponding to the height of the liquid surface 200, and the gas sensor element 1 is immersed in the slurry 2 to a required depth. The slurry film 3 can be accurately applied to the predetermined application range H. When the coating process is completed, the shutter 36 is closed, the temperature/humidity control chamber 21 communicates with the sealed moisturizing space 25, and the control air CA is maintained within a predetermined temperature/humidity range while the ambient air is cut off. Therefore, during the period in which the slurry is not applied, the liquid surface 200 can be kept stable by preventing drying, and the slurry film 3 having a uniform thickness can be formed on the gas sensor element 1 in the next application step.

In addition, since the control air CA is forcibly circulated from the control air generator 23 to the temperature/humidity control room 21, the temperature and humidity of the moisturizing space 25 can be dynamically controlled to suppress humidity fluctuations due to temperature changes. is. Moreover, since the control air CA is supplied to the slurry liquid surface 200 as a slow air flow that is deactivated by the small holes 44 of the intermediate plate 42, there is no possibility that the liquid surface 200 will be undulated by the blowing air, and dust will be mixed into the slurry 2. Don't worry about it. Therefore, it is possible to continuously form slurry films 3 of the same thickness on a large number of gas sensor elements 1 and reduce the number of workpieces treated as defective products by weight measurement.

During maintenance of the dipping tank 13, the worker M can easily carry the dipping tank 13 into and out of the temperature/humidity control room 21 using the ball guide 26. - 特許庁Since the clutch 34 separates the stirring blades 20 from the motor 32 when the dipping tank 13 is carried in and out, the total weight of the dipping tank 13 is reduced. Further, by pulling out the dip tank 13 to the maintenance position outside the temperature/humidity tank 14, maintenance work such as slurry exchange and tank interior cleaning can be easily performed in an open space.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and as exemplified below, the shape and configuration of each part can be changed as appropriate without departing from the scope of the invention.
(1) In the above embodiment, the control air generator 23 is installed at a location away from the base 11 of the dipping device 10. However, in another embodiment, the control air generator is installed on the base of the dipping device. It can also be installed.

(2) In the above embodiment, a plurality of gas sensor elements 1 are supported by the setter 4 and immersed in the slurry 2 by the loader 18. It is not limited and can be increased or decreased as appropriate, and one element 1 can be immersed in the slurry in one stroke of the loader 18 .
(3) In the above embodiment, the gas sensor element 1 was used as an example of a work, but the dipping device of the present invention can also be applied to other articles, particularly various parts or products whose surface is processed with a porous material. be.

1... gas sensor element (workpiece), 2... slurry, 200... liquid level,
10... Dip device, 13... Dip bath, 14... Temperature and humidity bath,
18... Loader, 19... Liquid level sensor, 21... Temperature and humidity control room,
23... Controlled air generator, 25... Moisturizing space, 36... Shutter.

Claims (6)

a dip tank (13) for storing the slurry (2);
a liquid level sensor (19) for detecting the height of the liquid level (200) of the slurry;
a loader (18) that ascends and descends with a stroke corresponding to the height of the liquid surface and immerses the workpiece in the slurry;
A temperature and humidity bath (14) forming a temperature and humidity control room (21) around the dip bath;
a shutter (36) that opens and closes the liquid surface of the slurry from above the temperature and humidity bath;
a stirring blade (20) for stirring the slurry in the dip tank;
a motor (32) that rotates the stirring blade;
a clutch (34) that disconnects the stirring blade from the motor when the dipping tank moves,
When the shutter is closed, a moisturizing space (25) is formed between the shutter and the liquid surface of the slurry, and the temperature and humidity control chamber communicates with the moisturizing space ,
A dipping device, wherein the dipping bath is provided so as to be movable into and out of the temperature/humidity control room from an entrance (27) of the temperature/humidity bath . 2. The dipping device according to claim 1 , wherein the dipping bath is provided with a lid member (28) that closes the entrance of the temperature/humidity bath when the dipping bath is placed in the temperature/humidity controlled chamber. a controlled air generator (23) for generating controlled air (CA) with controlled temperature and humidity;
The dipping device according to claim 1 or 2 , further comprising a piping member (22) for circulating the controlled air to the temperature/humidity control chamber. A middle plate (42) is provided on the upper surface of the temperature and humidity bath, and a plurality of small holes ( 44 ) are formed in the middle plate for communicating the temperature and humidity control chamber with the moisturizing space. A dipping device according to any one of claims 1 to 3. The dipping device according to any one of claims 1 to 4 , wherein a tray (40) for receiving the work dropped from the loader is provided above the shutter. 6. The shutter according to any one of claims 1 to 5 , wherein the shutter is provided with a material input port (41) for inputting the slurry constituent material into the slurry in the dip tank, and a door (46) for opening and closing the material input port. or the dipping device according to item 1.

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