JP2009291674A - Glaze application method, and glaze application apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glaze application method and a glaze application apparatus capable of applying a glaze with a uniform film thickness onto an object to be coated. <P>SOLUTION: The glaze application method includes an immersion process of immersing a part 12 to be coated of an object 1 to be coated having a rotationally symmetrical external shape in a glaze 3 while holding the object 1 by its non-coated part 11 and rotating it on its axis at a prescribed rotation speed and a pull-up process of pulling up the immersed object 1 out of the glaze 3 while rotating the object 1 on its axis at a prescribed rotation speed. Since the viscosity of the glaze 3 in the vicinity of the surface of the object 1 is reduced, the glaze 3 can be applied with a uniform film thickness. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a glaze application method and a glaze application apparatus for uniformly applying glaze to a coating object such as a spark plug with a predetermined film thickness.

  Conventionally, as a method for applying glaze to the insulator surface of the spark plug, for example, a method using a roller 91 is known as shown in FIG. In this method, the roller 91 has an outer surface shape that matches the surface of the insulator 92 (application object), and while the glaze is being supplied, the roller 91 is brought into contact with the insulator 92 and rotated, whereby the glaze is applied to the surface of the insulator 92. Transcript. As shown in FIG. 10B, a method is also known in which the non-application part is covered with a masking jig 93 and the glaze is sprayed onto the insulator 92 by the injection nozzle 94 (see Patent Documents 1 and 2).

Japanese Laid-Open Patent Publication No. 11-273486 JP 2002-326885 PR

  However, since the glaze contains fine particles such as hard glass, there is a problem that the surface of the roller 91 is worn by use. As a result, a contact failure between the roller 91 and the insulator 92 occurs, and there is a problem that a region where no glaze is applied is formed or a film thickness failure occurs.

  Further, the method using the injection nozzle 94 has a problem that the glaze is clogged in the injection port. As a result, there was a problem that the glaze was not sufficiently sprayed, and the uncoated portion of the glaze was formed, or a film thickness defect occurred.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a glaze application method and a glaze application apparatus capable of applying glaze to a coating object with a uniform film thickness.

1st invention is the method of apply | coating a glaze on the surface of the application target object which has the external shape which is rotation object,
Immersion step of holding the non-application part of the application object and immersing the application part in the glaze while rotating the shaft at a predetermined rotation speed;
A pulling-up step of pulling up the immersed coating object from the glaze while rotating the shaft at a predetermined rotational speed;
(1).

Next, the function and effect of the first invention will be described.
In the first invention, by utilizing the thixotropy of the glaze, the viscosity of the glaze on the surface of the application object can be locally lowered, and as a result, the glaze can be applied to the application object with a uniform film thickness. It becomes possible to apply.
That is, the glaze has a property (thixotropic property) in which the viscosity is low in a flowing state and the viscosity is high in a stationary state. Therefore, when the coating object is immersed in the glaze while rotating the axis, the flow rate of the glaze increases only near the surface of the coating object, and the viscosity is locally lowered. Thereby, it becomes possible to apply the glaze to the application object with a uniform film thickness.

  Here, if the coating object is immersed in the glaze without rotating the shaft, the viscosity of the glaze is relatively high, so the film thickness may not be uniform or the glaze may be too thick. In addition, when the outer surface shape is complicated, such as when uneven portions are formed on the surface of the application object, it is difficult to uniformly apply the glaze to fine gaps.

On the other hand, in the first invention, since the application object is immersed in the glaze while rotating around the axis and pulled up, the flow rate of the glaze on the surface of the application object can be increased, and the viscosity can be lowered locally. Therefore, the coating film thickness of the glaze can be made uniform, and even if the object to be coated has a complicated outer shape, it is possible to apply the glaze with a uniform thickness up to a fine gap.
Moreover, the viscosity of the glaze on the surface of the application target can be adjusted to a desired value by adjusting the rotation speed of the application target.

  As described above, according to the first aspect of the present invention, it is possible to provide a glaze application method capable of applying a glaze to a coating object with a uniform film thickness.

Further, the second invention is a glaze application device for applying glaze to the surface of an application object having an outer shape to be rotated,
A glaze tank for storing the glaze,
The non-immersion position is configured such that the non-application portion of the application object is held and the shaft is rotatable, and the application object is positioned vertically above the liquid surface of the glaze, and the application portion of the application object is A workpiece holding mechanism capable of moving up and down between the immersion positions immersed in the glaze,
In the glaze application device (claim 9), comprising:

Next, the function and effect of the second invention will be described.
In the second invention, by using the work holding mechanism, it is possible to apply the object to the glaze while rotating the application object and pull it up. Therefore, the glaze can be applied to the surface of the object to be coated with a uniform film thickness by the same effect as the first invention.

In addition, the second invention is also excellent in maintainability as compared with the conventional example. For example, in the conventional example shown in FIG. 10 (A), since the glaze contains particles such as hard glass, the roller 91 may be worn out. As a result, an uncoated region is formed or the film thickness is not good. There was a problem of becoming uniform. Therefore, it was necessary to replace the worn roller 91.
In the conventional example shown in FIG. 10B, the spray nozzle 94 may be clogged with the glaze. As a result, there is a problem that an uncoated area of the glaze is formed or the film thickness is not uniform. Therefore, it is necessary to periodically check the injection nozzle 94. Furthermore, in FIG. 10 (B), even if sprayed, there is a glaze that is not applied to the insulator 92 and adheres to the wall surface or the like of the glaze application device, so it has to be cleaned regularly. Further, since the glaze is injected at a high pressure, it is necessary to provide a high-pressure system, and there is a problem that the glaze application apparatus is expensive.

  On the other hand, since the glaze application device of the present invention does not use the roller 91 or the injection nozzle 94, the above problem does not occur and the maintainability is excellent. Moreover, since a high-pressure system for injecting the glaze as shown in FIG. 10B is not necessary, there is an advantage that an inexpensive device can be obtained.

  As described above, according to the second aspect of the present invention, it is possible to provide a glaze application apparatus that can apply glaze to a coating object with a uniform film thickness.

A preferred embodiment in each invention described above will be described.
1st invention WHEREIN: An uneven | corrugated | grooved part is formed in the said application part of the said application target object, and it adheres to the said uneven | corrugated | grooved part by sending the liquid flow of the said glaze with respect to the said uneven | corrugated part immersed in the said glaze. It is preferable to perform an air venting process for removing the generated bubbles.
In this case, since the air venting process is performed, the bubbles adhering to the concavo-convex portion can be removed. Thereby, it can prevent effectively that the uncoated part of the glaze to an application target object is formed, and the film thickness of the glaze applied to an application target object can be made uniform.

Moreover, in the state where all the areas of the application part are immersed in the glaze, it is preferable to stop sending the liquid flow of the glaze.
In this case, the liquid surface of the glaze can be made stationary while all areas of the application portion are immersed in the glaze. For this reason, it is possible to prevent the glaze from adhering to the portion of the application object where the glaze should not be originally applied because the liquid level of the glaze is shaken.

Moreover, the application | coating lower side area | region containing the said uneven | corrugated | grooved part among the said application parts is immersed in the said glaze, and the application | coating upper area | region which exists above the said application | coating lower area | region among the said application parts is not immersed in the said glaze. Perform the air bleeding step at the first immersion position,
It is preferable to perform a delivery stop step of lowering the application object to the second immersion position where all areas of the application part are immersed in the glaze in a state where the delivery of the liquid flow of the glaze is stopped (Claim 4). .
In this case, it is possible to prevent bubbles from adhering to the concavo-convex portion and to prevent glaze from adhering to the non-application portion.
That is, since the liquid level of the glaze is shaken when the air venting process is performed, the air venting process is performed in a state where the application object is held at the first immersion position. Therefore, even if the liquid level of the glaze is slightly shaken, the glaze only adheres to the application upper region and does not adhere to the non-applied portion.
In addition, when the entire area of the application portion is immersed in the glaze, the glaze liquid level does not shake because the glaze delivery is stopped (delivery stop process). Thereby, it can prevent that a glaze adheres to the part which should not apply | coat a glaze originally in a coating target object.

Preferably, the first air bleeding step is performed before the delivery stop step, and the second air bleeding step is performed after the delivery stop step.
In this case, since the air venting process is performed before and after the delivery stop process, the bubbles adhering to the concavo-convex part can be reliably removed.

Further, in a state where at least a part of the application part is immersed in the glaze, the application object is axially rotated at a first rotation speed,
After the pulling-up step, it is preferable to perform a high-speed rotation step in which the application object is rotated at a second rotation speed that is faster than the first rotation speed.
In this case, by performing a high-speed rotation process, the excess glaze applied to the application target can be removed using centrifugal force.
The first rotation speed and the second rotation speed do not necessarily have to be constant.

Further, the application object is configured in a cylindrical shape having both axial ends open, and the application part can be immersed in the glaze in a state where the upper opening of the application object is hermetically sealed. Preferred (claim 7).
In this case, since the upper opening of the object to be applied is hermetically sealed, even if the lower (application part side) opening is immersed in the glaze, the glaze is not removed from the lower opening. It will not enter. Thereby, it can prevent that a glaze adheres to the inner side of a coating target object.

Further, it is preferable that the application object is an insulator of a spark plug.
In this case, the effect of the first invention can be sufficiently exerted. In other words, since the insulator of a spark plug is generally formed with uneven portions (corrugation portions) and has a relatively complicated shape, it is difficult to uniformly apply the glaze, and bubbles are attached to the uneven portions. There is a problem that it is easy. In addition, in order to ensure insulation between the inner side and the outer side of the insulator of the spark plug, glaze is applied to the outer surface, but if this glaze is not uniformly applied, sufficient insulation resistance cannot be secured. There's a problem. By using said 1st invention, a glaze can be apply | coated to the surface of an insulator with uniform thickness, and the function can fully be exhibited.

Further, in the second invention, it is preferable to provide a glaze jet nozzle for sending a liquid flow of the glaze to the application part immersed in the glaze.
In this case, it is possible to prevent bubbles from adhering to the application part immersed in the glaze.

Further, it is preferable that a stirring device for stirring the glaze is provided in the glaze tank.
In this case, precipitation of the solid content of the glaze can be prevented and the temperature of the glaze in the glaze tank can be kept constant.

Moreover, it is preferable that the application object is formed in a cylindrical shape having both ends in the axial direction open, and includes a seal portion that hermetically seals the upper opening of the application object.
In this case, the upper opening of the object to be coated can be hermetically sealed, so that even if the lower (application portion side) opening is immersed in the glaze, the glaze does not enter from the lower opening. . Thereby, it can prevent that a glaze adheres to the inner side of a coating target object.

In addition, an overflow tank surrounding the glaze tank, and the glaze overflowing from the upper edge of the glaze tank to the overflow tank by sending the glaze to the inside of the glaze tank, and the overflowing glaze It is preferable to provide a glaze circulation mechanism that collects and circulates (claim 13).
In this case, since the glaze always overflows from the upper edge of the glaze tank, the liquid level of the glaze can be kept at a constant height. Thereby, the depth of the part immersed in a glaze can be controlled accurately. Therefore, the glaze can be applied only to a desired site in the application object.

Further, the work holding mechanism includes a first immersion position in which the application lower region is immersed in the glaze, and the application upper region existing above the application lower region in the application portion is not immersed in the glaze. And in a state where the application object can be immersed in two stages of the second immersion position where all of the application part is immersed in the glaze, and the delivery of the glaze from the glaze ejection nozzle is stopped, It is preferable to include a control unit that immerses the application object to the second immersion position (claim 14).
In this case, by sending the glaze at the first immersion position, air bubbles adhering to the application target can be removed, and at the second immersion position, the glaze delivery is stopped. Can be prevented. Thereby, it can prevent that a glaze adheres to a non-application part.

(Example 1)
The glaze application method according to the embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 to 3, the glaze 3 is applied to the surface of the coating object 1 by immersing and lifting the coating object 1 (insulator of the spark plug) in the glaze 3 while rotating the shaft.

  As shown in FIG. 4B, the application object 1 has an outer shape to be rotated. In the glaze application method of this example, the glaze 3 is applied to the surface of the application object 1 having the outer shape to be rotated in this way. First, as shown in FIG. 1, the non-application | coating part 11 of the application target object 1 is hold | maintained, and the immersion process which immerses the application part 12 in the glaze 3 is performed, rotating axially with a predetermined | prescribed rotational speed. Next, as shown in FIG. 3, a pulling process of pulling up the immersed coating object 1 from the glaze 3 while rotating the shaft at a predetermined rotational speed is performed.

Moreover, as shown in FIG. 1, the uneven | corrugated | grooved part 13 is formed in the application part 12 of the application target object 1. As shown in FIG. By sending a liquid flow 32 of the glaze 3 to the uneven portion 13 immersed in the glaze 3, an air venting process for removing the bubbles 4 attached to the uneven portion 13 is performed.
Further, as shown in FIG. 2, in the state where all areas of the application portion 12 are immersed in the glaze 3, the delivery of the liquid flow 32 of the glaze 3 is stopped.

  More specifically, as shown in FIG. 1, the application lower region 121 including the concavo-convex portion 13 in the application portion 12 is immersed in the glaze 3, and the application upper side existing above the application lower region 121 in the application portion 12. An air bleeding step is performed at the first immersion position where the region 122 is not immersed in the glaze 3. Then, as shown in FIG. 2, in the state where the delivery of the liquid flow 32 of the glaze 3 is stopped, a delivery stop step of lowering the application target 1 to the second immersion position where all the areas of the application part 12 are immersed in the glaze 3 is performed. Do.

  Further, as shown in FIG. 4A, the application object 1 is formed in a cylindrical shape having both ends in the axial direction opened, and the upper opening 15 of the application object 1 is airtight as shown in FIG. The coated portion 12 is dipped in the glaze 3 in a state where it is sealed.

  Next, the overall flow of the glaze application method will be described with reference to FIG. First, in the setting process, the non-application part 11 of the application object 1 is held and conveyed onto the liquid surface of the glaze 3 (step S1). Until the setting process is completed, the application target 1 does not rotate as shown by L1. Further, the glaze ejection nozzle 23 is attached to a stirring device 24 (not shown) which will be described later. As indicated by L2, the glaze is accompanied by the stirring operation of the stirring device 24 until the setting process is completed. The ejection nozzle 23 moves up and down. Further, as indicated by L3 and L4, the glaze 3 is delivered from the glaze jet nozzle 23 and the lower nozzle 29 (not shown).

  Next, as indicated by L1, the application object 1 begins to rotate at a low speed (300 rpm), and the glaze jet nozzle 23 is stopped below the liquid surface 31 of the glaze 3 as indicated by L2. In the descending step, the application object 1 is lowered, and the application portion 12 is immersed in the glaze 3 (step S2).

  Next, in the first air bleeding step, the application target 1 is lowered to the first immersion position (step S3).

  Next, as indicated by L3 and L4, the delivery of the glaze 3 is stopped from the glaze jet nozzle 23 and the lower nozzle 29. Thereafter, in the delivery stop step, the application target 1 is lowered to the second immersion position (step S4).

  Next, in the second air bleeding process, the application target 1 is pulled up to the first process (step S5). In the second air venting process, the glaze 3 is restarted from the glaze jet nozzle 23 and the lower nozzle 29 as indicated by L3 and L4.

  Thus, the glaze application method of the present example performs the first air venting process (step S3) before the delivery stop process (step S4), and the second air venting process (step S5) after the delivery stop process. It is carried out.

  Next, in the pulling-up process, the coating object 1 is pulled up from the glaze 3 (step S6). Next, after the pulling-up process, a high-speed rotation process is performed in which the coating object 1 is rotated at a second rotation speed that is faster than the first rotation speed (step S7). At this time, as indicated by L1, the rotation speed of the coating object 1 is set to 1600 rpm.

As described above, in a state where at least a part of the application portion 12 is immersed in the glaze 3 (steps S1 to S6), the application target 1 is axially rotated at the first rotation speed (low speed).
In this example, the first rotation speed (low-speed rotation) is 300 rpm, and the second rotation speed (high-speed rotation) is 1600 rpm. Moreover, after starting a high-speed rotation process, as shown to L2, the vertical motion of the glaze ejection nozzle 23 is restarted.
The first rotation speed and the second rotation speed do not necessarily have to be constant speeds. For example, the rotation speed can be gradually increased or gradually decreased.

  When the high-speed rotation process ends, the stirring operation of the stirring device 24 (not shown) is started, and accordingly, the vertical operation of the glaze jet nozzle 23 is started as indicated by L2.

Next, a glaze application apparatus according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 6 to 9, the glaze application apparatus 2 of this example applies the glaze 3 to the surface of the application object 1 having an outer shape to be rotated. The glaze application device 2 includes a glaze tank 21 for storing the glaze 3. The non-immersion position (FIG. 5: step S1) is configured such that the non-application portion 11 of the application object 1 is held and the shaft is rotatable, and the application object 1 is positioned above the liquid surface 31 of the glaze 3 in the vertical direction. (See FIG. 5: Steps S3 to S5) and a workpiece holding mechanism 22 that can move up and down between the application portion 12 and the application portion 12 of the application object 1 is immersed in the glaze 3.
7 to 9, the work holding mechanism 22, a seal portion 25 and a glaze circulation mechanism 27 described later are omitted.

Next, as shown in FIGS. 6, 8, and 9, the glaze application device 2 of this example includes a glaze ejection nozzle 23 that sends a liquid flow 32 of the glaze 3 to the application portion 12 immersed in the glaze 3. Prepare.
As shown in FIG. 6, the glaze delivery nozzle 23 discharges the glaze 3 sent from the pump 55 of the glaze circulation mechanism 27, and bubbles 4 attached to the application object 1 by the liquid flow of this glaze 3 (see FIG. 2). Has been removed. A lower nozzle 29 is provided at the bottom of the glaze tank 4, and the glaze 3 is also sent to the lower nozzle 29.
As shown in FIGS. 7 to 9, the glaze application device 2 is configured to be able to process a plurality (10 in this example) of application objects 1 at a time. One glaze jet nozzle 23 is arranged for one application object 1.

A stirring device 24 for stirring the glaze 3 is provided in the glaze tank 21.
More specifically, as shown in FIG. 8, the stirring device 24 is made of a wire mesh, and is stirred up and down in the glaze tank 21 so that the solid content of the glaze 3 does not precipitate. The above-described glaze ejection nozzle 23 is attached to the stirring device 24.

  Next, as shown in FIG. 6, the application target 1 is configured in a cylindrical shape having both ends in the axial direction open, and includes a seal portion 25 that hermetically seals the upper opening 15 of the application target 1. .

  Moreover, the glaze application apparatus 2 of this example is provided with the overflow tank 26 surrounding the glaze tank 21, as shown in FIG. Then, by sending the glaze 3 to the inside of the glaze tank 21, the glaze 3 overflows from the upper end edge 211 of the glaze tank 21 to the overflow tank 26, and the glaze circulation mechanism that collects and circulates the overflowing glaze 3 27.

  More specifically, the glaze circulation mechanism 27 includes a glaze discharge pipe 261 connected to the bottom of the overflow tank 26, a glaze tank 5 connected to the glaze discharge pipe 261, a pump 55 for sending the glaze 3, a pump The delivery pipe 262 is connected to 55, and the glaze ejection nozzle 23 and the lower nozzle 29 that serve as the outlet of the glaze 3 are configured.

  Next, the glaze application device 2 of this example includes a control device 28 connected to the workpiece holding mechanism 22, the stirring device 24, the pump 55, and the like, and the control device 28 performs each step shown in FIG. Control.

  Further, as shown in FIG. 6, the work holding mechanism 22 has the coating lower region 121 immersed in the glaze 3, and the coating upper region 122 existing above the coating lower region 121 in the coating portion 12 is the glaze 3. The object 1 can be immersed in two stages: a first immersion position (see FIG. 1) that is not immersed and a second immersion position (see FIG. 2) in which the coating portion 12 is all immersed in the glaze 3. Is done. And the control part 28 is controlled in the state which stopped sending out the glaze 3 from the glaze ejection nozzle 23 so that the application target object 1 may be immersed to the 2nd immersion position.

  The glaze tank 5 is provided with an in-tank stirring device 51, a temperature sensor 52, a viscosity sensor 53, and a cooler 54. These are connected to the control unit 28, and the control unit 28 controls the temperature and viscosity of the glaze 3 in the glaze tank 5 to be in a certain range.

Next, the effect of the glaze application method of this example will be described.
As shown in FIG. 1, in the glaze application method of this example, an immersion process of immersing the coating object 1 in the glaze 3 while rotating the axis, and a pulling process of pulling up from the glaze 3 while rotating the axis are performed.
Thereby, the viscosity of the glaze 3 on the surface of the application target object 1 can be locally lowered, and as a result, the glaze 3 can be applied to the application target object 1 with a uniform film thickness.
That is, the glaze 3 has a property (thixotropic property) in which the viscosity is low in a flowing state and the viscosity is high in a stationary state. Therefore, when the coating object 1 is immersed in the glaze 3 while rotating the axis, the flow rate of the glaze 3 is increased only near the surface of the coating object 1, and the viscosity is locally reduced. Thereby, it becomes possible to apply the glaze 3 to the application object 1 with a uniform film thickness.

  Here, if the coating object 1 is immersed in the glaze 3 without rotating the axis, the viscosity of the glaze 3 is relatively high, so the film thickness may not be uniform or the glaze 3 may be too thick. is there. In addition, when the outer surface shape is complicated, such as when the uneven portion 13 is formed on the surface of the application object 1, it is difficult to uniformly apply the glaze 3 to the fine gaps.

On the other hand, in this example, since the application target 1 is immersed in the glaze 3 while rotating the shaft, the flow rate of the glaze 3 on the surface of the application target 1 can be increased, and the viscosity can be locally reduced. it can. Therefore, the coating film thickness of the glaze 3 can be made uniform, and even if the coating object 1 has a complicated outer shape, it is possible to apply the glaze 3 with a uniform thickness up to a fine gap.
Moreover, the viscosity of the glaze 3 on the surface of the application target 1 can be adjusted to a desired value by adjusting the rotation speed of the application target 1.

  Next, as shown in FIGS. 1 and 2, in the glaze application method of this example, an air bleeding step is performed. Thereby, the bubble 4 adhering to the uneven part 13 can be removed. Therefore, the film thickness of the glaze 3 applied to the application target 1 can be made uniform.

Further, in the glaze application method of this example, as shown in FIG. 2, in the state where all areas of the application portion 12 are immersed in the glaze 3, the sending of the liquid flow 32 of the glaze 3 is stopped.
In this case, the liquid surface 31 of the glaze 3 can be made still in a state where all the areas of the application portion 12 are immersed in the glaze 3. Therefore, it is possible to prevent the glaze 3 from adhering to the portion (non-application portion 11) that should not be applied with the glaze because the liquid surface 31 of the glaze 3 shakes.

More specifically, as shown in FIGS. 1 and 2, the glaze application method of this example performs the air venting process at the first immersion position and stops the delivery of the liquid flow 32 of the glaze 3 as described above. (2) A delivery stop process for lowering the application target 1 to the immersion position is performed.
In this case, it is possible to prevent the bubbles 4 from adhering to the concavo-convex portion 13 and to prevent the glaze 3 from adhering to a portion where the glaze should not be originally applied (non-application portion 11).
That is, since the liquid level 31 of the glaze 3 is shaken when the air venting process is performed, the air venting process is performed in a state where the coating object 1 is held at the first immersion position. Therefore, even if the liquid surface 31 of the glaze 3 slightly fluctuates, the glaze 3 only adheres to the application upper region 122 and does not adhere to the non-application part 11.
In addition, when the entire area of the application portion 12 is immersed in the glaze 3, the liquid surface 31 of the glaze 3 does not shake because the delivery of the glaze 3 is stopped (delivery stop process). Thereby, it can prevent that the glaze 3 adheres to the non-application part 11. FIG.

More specifically, as shown in FIG. 5, the glaze application method of the present example performs the first air venting process before the delivery stop process, and performs the second air vent process after the delivery stop process.
In this case, since the air venting process is performed before and after the delivery stopping process, the bubbles 4 attached to the uneven portion 13 can be reliably removed.

Next, as shown in FIG. 5, the glaze application method of this example rotates the shaft at the first rotational speed from the setting step (step S 1) to the lifting step (step S 6). A high-speed rotation process (step S7) for rotating the shaft at a second rotation speed higher than the rotation speed of 1 is performed.
In this case, by performing a high-speed rotation process, the excess glaze 3 applied to the application target 1 can be removed using centrifugal force.
Further, the first rotation speed and the second rotation speed can be appropriately adjusted according to the composition and viscosity of the glaze 3. If the first rotational speed is too high, the glaze 3 will adhere to the non-application portion 11. On the other hand, if the first rotational speed is too slow, it is difficult to make the film thickness of the glaze 3 uniform. Furthermore, if the second rotational speed is too fast, the film thickness of the glaze 3 becomes too thin, and if it is too slow, the film thickness of the glaze 3 becomes too thick.

Moreover, the glaze application | coating method of this example immerses the application part 12 in the glaze 3 in the state which airtightly sealed the opening part 15 of the upper side of the application target object 1 as shown in FIG. 1, FIG.
In this case, since the upper opening 15 of the application object 1 is hermetically sealed, even if the lower (application part 12 side) opening 14 is immersed in the glaze 3, The glaze 3 does not enter from the opening 14. Thereby, it can prevent that the glaze 3 adheres to the inner side of the application target object 1. FIG.

Moreover, as shown in FIG. 1, the application target object 1 is an insulator of a spark plug.
In this case, the effect of the glaze application method according to this example can be sufficiently exerted. That is, since the insulator of the spark plug has a concavo-convex portion 13 (corrugation portion) and has a relatively complicated shape, it is difficult to apply the glaze 3 uniformly, and air bubbles are formed in the concavo-convex portion 13. There is a problem that 4 is easily attached. Furthermore, the insulator is configured in a cylindrical shape, and there are certain restrictions such as that the glaze 3 should not be applied to the inside. When the glaze 3 adheres to the inside, it becomes impossible to attach a center electrode (not shown) in a later process. Moreover, if the glaze 3 adheres to the outer portion where the glaze 3 should not be applied, it becomes impossible to mount a housing (not shown) in a later process. Therefore, it is necessary to apply the glaze 3 precisely only to the application part.
By using the glaze application method of this example, the glaze 3 can be applied to the surface of the insulator with a uniform thickness even when there are these problems and restrictions.

Next, the effect of the glaze application apparatus 2 of this example is demonstrated.
As shown in FIG. 6, the glaze application device 2 of this example includes a glaze tank 21 and a work holding mechanism 22.
By this work holding mechanism 22, the application object 1 can be applied to the glaze 3 while being pivoted and pulled up. When the shaft rotates, the flow rate of the glaze 3 on the surface of the application target 1 increases, and the viscosity of the glaze 3 locally decreases. Therefore, the glaze 3 can be applied to the surface of the application object 1 with a uniform film thickness.

Moreover, the glaze application apparatus 2 of this example is excellent also in maintainability compared with a prior art example. For example, in the conventional example shown in FIG. 10 (A), since the glaze contains particles such as hard glass, the roller 91 may be worn out. As a result, an uncoated region is formed or the film thickness is not good. There was a problem of becoming uniform. Therefore, it was necessary to replace the worn roller 91.
In the conventional example shown in FIG. 10B, the spray nozzle 94 may be clogged with the glaze. As a result, there is a problem that an uncoated area of the glaze is formed or the film thickness is not uniform. Therefore, it is necessary to periodically check the injection nozzle 94. Furthermore, in FIG. 10 (B), even if sprayed, there is a glaze that is not applied to the insulator 92 and adheres to the wall surface or the like of the glaze application device, so it has to be cleaned regularly. Further, since the glaze is injected at a high pressure, it is necessary to provide a high-pressure system, and there is a problem that the glaze application apparatus is expensive.

  On the other hand, in the glaze coating device 2 of this example, since the roller 91 and the injection nozzle 94 are not used, the said problem does not generate | occur | produce and it is excellent in maintainability. Moreover, since a high-pressure system for injecting the glaze as shown in FIG. 10B is not necessary, there is an advantage that an inexpensive device can be obtained.

Moreover, the glaze application apparatus 2 of this example is provided with the glaze jet nozzle 23 which sends out the liquid flow 32 of the glaze 3 with respect to the application part 12 immersed in the glaze 3, as shown in FIGS.
In this case, it is possible to prevent the bubbles 4 from adhering to the application portion 12 immersed in the glaze 3.

Next, as shown in FIGS. 6 to 9, the glaze application device 2 of this example is provided with a stirring device 24 for stirring the glaze 3 in the glaze tank 21.
In this case, precipitation of the solid content of the glaze 3 can be prevented, and the temperature of the glaze 3 in the glaze tank 21 can be kept constant.

Moreover, the glaze application apparatus 2 of this example is provided with the seal part 25 which airtightly seals the opening 15 on the upper side of the application target 1 as shown in FIG.
In this case, since the upper opening 15 of the application target 1 can be hermetically sealed, even if the lower (application part 12 side) opening 14 is immersed in the glaze 3, the lower opening The glaze 3 will not enter from 14. Thereby, it can prevent that the glaze 3 adheres to the inner side of the application target object 1. FIG.

Further, as shown in FIG. 6, the glaze application apparatus 2 of this example includes an overflow tank 26, and the glaze 3 overflows from the upper end edge 211 of the glaze tank 21 into the overflow tank 26.
In this case, the liquid surface 31 of the glaze 3 can be kept at a constant height. Thereby, the depth of the part immersed in the glaze 3 can be controlled accurately. Therefore, the length of the glaze 3 to be applied can be made constant.

Moreover, as shown in FIG. 6, the glaze application apparatus 2 of this example can immerse the application target object 1 in two stages (see FIG. 1 and FIG. 2) of the first immersion position and the second immersion position. The control part 28 comprised is comprised, and the application target object 1 is immersed in a 2nd immersion position in the state which stopped sending out the glaze 3 from the glaze ejection nozzle 23.
In this case, by sending the glaze 3 at the first soaking position, the bubbles 4 attached to the application target 1 can be removed, and at the second soaking position, the sending of the glaze 3 is stopped. The surface 31 can be prevented from shaking. Thereby, it can prevent that the glaze 3 adheres to the non-application part 11. FIG.

  As described above, according to this example, it is possible to provide the glaze application method and the glaze application apparatus 2 that can apply the glaze 3 to the application target 1 with a uniform film thickness.

The enlarged view of the immersion process (a 1st air bleeding process, a 2nd air bleeding process) in Example 1. FIG. The enlarged view of the immersion process (delivery stop process) in Example 1. FIG. The enlarged view of the pulling-up process in Example 1. FIG. In Example 1, (A) Longitudinal sectional view of an object to be coated (B) A sectional view taken along the line aa in FIG. The whole process figure of the glaze application method in Example 1. FIG. The conceptual diagram of the glaze application apparatus in Example 1. FIG. It is detail drawing of the glaze application apparatus in Example 1, Comprising: CC sectional view taken on the line of FIG. AA arrow sectional drawing of FIG. BB arrow sectional drawing of FIG. A method of applying glaze to an insulator in a conventional example, wherein (A) an application method using a roller (B) an application method using an injection nozzle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Application | coating object 11 Non-application | coating part 12 Application | coating part 121 Application | coating lower side area | region 122 Application | coating upper part area | region 13 Uneven part 2 Glaze application apparatus 21 Glaze tank 211 Upper edge of a glaze tank 22 Work holding mechanism 23 Glaze ejection nozzle 25 Seal part 26 Overflow tank 3 Glaze 4 Bubble

Claims (14)

A method of applying glaze to the surface of an application object having an outer shape to be rotated,
Immersion step of holding the non-application part of the application object and immersing the application part in the glaze while rotating the shaft at a predetermined rotation speed;
A pulling-up step of pulling up the immersed coating object from the glaze while rotating the shaft at a predetermined rotational speed;
The glaze application method characterized by performing.   In Claim 1, the uneven | corrugated | grooved part is formed in the said application part of the said application | coating target object, and it adhered to the said uneven | corrugated | grooved part by sending the liquid flow of the said glaze with respect to the said uneven | corrugated part immersed in the said glaze. A glaze application method comprising performing an air venting process for removing bubbles.   3. The glaze application method according to claim 2, wherein in the state where all the areas of the application part are immersed in the glaze, the liquid flow of the glaze is stopped. In Claim 2, the application | coating lower side area | region containing the said uneven | corrugated | grooved part among the said application parts is immersed in the said glaze, and the application | coating upper area | region which exists above the said application | coating lower side area | region among the said application parts is immersed in the said glaze. Perform the air venting step at the first dipping position,
A glaze application method comprising performing a delivery stop step of lowering the object to be applied to a second immersion position where all areas of the application part are immersed in the glaze in a state where the delivery of the liquid flow of the glaze is stopped .   5. The glaze application method according to claim 4, wherein the first air bleeding step is performed before the delivery stop step, and the second air bleeding step is performed after the delivery stop step. In any one of Claims 1 thru | or 5, in the state in which at least one part of the said application part was immersed in the said glaze, the said application target object is axially rotated at the 1st rotational speed,
After the pulling-up step, the glaze application method is characterized in that a high-speed rotation step of rotating the application object at a second rotation speed faster than the first rotation speed is performed.   In any 1 item | term of the Claims 1 thru | or 6, the said application target object is comprised in the cylinder shape which the axial direction both ends opened, The state which airtightly sealed the upper opening part of this application target object The glaze application method is characterized in that the application part is immersed in the glaze.   8. The glaze application method according to claim 1, wherein the application object is an insulator of a spark plug. A glaze application device for applying glaze to the surface of a coating object having an outer shape to be rotated,
A glaze tank for storing the glaze,
The non-immersion position is configured such that the non-application portion of the application object is held and the shaft is rotatable, and the application object is positioned vertically above the liquid surface of the glaze, and the application portion of the application object is A workpiece holding mechanism capable of moving up and down between the immersion positions immersed in the glaze,
A glaze application device comprising:   The glaze application device according to claim 9, further comprising a glaze ejection nozzle that sends a liquid flow of the glaze to the application portion immersed in the glaze.   11. The glaze application apparatus according to claim 9 or 10, wherein a stirring device for stirring the glaze is provided in the glaze tank.   12. The seal according to claim 9, wherein the application object is formed in a cylindrical shape having both axial ends opened, and the opening on the upper side of the application object is hermetically sealed. A glaze application device comprising a portion.   In any one of Claims 9-12, the said glaze is sent to the said overflow tank from the upper end edge of the said glaze tank by sending out the said glaze to the overflow tank which surrounds the said glaze tank, and the said glaze tank inside A glaze application apparatus comprising: a glaze circulation mechanism that causes the glaze to overflow and collect and circulate the overflowing glaze.   11. The work holding mechanism according to claim 10, wherein the application lower region of the application portion is immersed in the glaze, and the application upper region existing above the application lower region of the application portion is the glaze. The glaze from the glaze jet nozzle is configured so that the coating object can be dipped in two stages of a first dipping position that is not dipped and a second dipping position in which the application part is all dipped in the glaze. A glaze application device comprising: a control unit that immerses the application object to the second immersion position in a state where the feeding of the liquid is stopped.

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