JP5829555B2 - Electrostatic coating apparatus and electrostatic coating method - Google Patents

Description

  The present invention relates to an electrostatic coating apparatus and an electrostatic coating method. Specifically, the present invention relates to a rotary atomizing electrostatic coating apparatus and an electrostatic coating method.

  2. Description of the Related Art Conventionally, a rotary atomizing electrostatic coating apparatus is known as a coating apparatus for coating a car body or the like. This electrostatic coating apparatus rotates at a high speed while applying a high voltage to the rotary atomizing head, and supplies a conductive liquid paint to the rotary atomizing head in this state. As a result, the liquid paint is charged and atomized, and sprayed from the leading edge of the rotary atomizing head to perform electrostatic coating.

  By the way, in order to direct the paint atomized by the rotary atomizing head in the direction of the object to be coated, a technique for ejecting shaping air from the rear of the rotary atomizing head toward the outer peripheral edge is known. However, this technique has a problem in that a negative pressure is generated at the front center of the rotary atomizing head by ejecting the shaping air, and the shaping air is sucked into the center by this negative pressure and the coating pattern becomes narrow.

  Therefore, a technique for ejecting shaping air in a twisting (twisting) direction with respect to the rotation axis of the rotary atomizing head has been disclosed (see Patent Document 1). According to this technique, the centrifugal force is generated by the shaping air flowing in a spiral shape, and the centrifugal force can be prevented from being drawn to the center and narrowing the coating pattern.

  Moreover, the technique which eliminates the negative pressure which generate | occur | produces in the front center of a rotation atomization head is disclosed by ejecting air toward the front from the center air ejection nozzle provided in the center part of a rotation atomization head. (See Patent Document 2). According to this technique, the negative pressure can be eliminated and the air flow velocity in the vicinity of the surface of the object can be made uniform. In addition, since the drying degree and the collision speed of the paint particles are equalized, the variation in brightness is reduced, and a good coating film is obtained.

JP-A-3-101858 JP 2000-5645 A

  However, in the current state of the art, the negative pressure generated at the front center of the rotary atomizing head cannot be sufficiently suppressed. Therefore, since shaping air is sucked into the negative pressure region and the paint is not sufficiently directed in the direction of the object to be coated, there is a problem that a desired coating pattern cannot be formed and the coating efficiency is lowered.

  The present invention has been made in view of the above, and an object thereof is to provide an electrostatic coating apparatus and an electrostatic coating method capable of forming a desired coating pattern and improving the coating efficiency.

In order to achieve the above object, the present invention comprises a rotary atomizing head (for example, a rotary atomizing head 22 to be described later) that charges and atomizes a paint by rotating in a state where a high voltage is applied, and the rotation. A static electricity provided with a shaping air ejection hole (for example, a shaping air ejection hole 41 to be described later) formed around the atomizing head and ejecting shaping air for directing the atomized paint in the direction of the object. A coating apparatus (for example, an electrostatic coating apparatus 1 described later) is provided. The electrostatic coating apparatus according to the present invention is provided in a central portion of the rotary atomizing head, and generates a plurality of air ejection holes (for example, air ejection holes 212 described later) that generate coating pattern forming air by ejecting air. ) And a plurality of air suction holes (for example, air suction holes 214 described later) that generate paint pattern forming air by sucking air, and air nozzles (for example, air nozzles 21, 21a described later) having at least one of them. The shaping air ejection hole is formed such that the ejection direction of the shaping air is a twist direction with respect to a rotation axis (for example, rotation axis X described later) of the rotary atomizing head, and the air nozzle includes the plurality of air nozzles The air ejection hole is formed so that the air ejection direction is a twist direction opposite to the twisting direction of the shaping air. And wherein the Rukoto.

In the present invention, an air nozzle is provided in the central portion of the rotary atomizing head, and a plurality of air ejection holes for generating coating pattern forming air by blowing air to the air nozzle, and a coating pattern forming by sucking the air At least one of the plurality of air suction holes that generate the working air is formed.
Thereby, by ejecting air from a plurality of air ejection holes, negative pressure generated at the front center of the rotary atomizing head due to ejection of shaping air can be sufficiently suppressed, and the size of the coating pattern is expanded to a desired size. be able to. Moreover, by sucking air from the plurality of air suction holes, the negative pressure can be increased, and the size of the coating pattern can be reduced to a desired size. As described above, according to the present invention, the coating pattern forming air can be generated by ejecting or sucking air from the air nozzle, and a desired coating pattern can be formed by controlling the flow rate. Can be improved.
The “coating pattern forming air” in this specification means an air flow suitable for forming a desired coating pattern, which is generated at the front center portion by ejecting or sucking air from an air nozzle.

In the present invention, further, the ejection direction of the air with respect to twisting direction of the shaping air, forming an air ejection hole such that the reverse twist direction. Here, even when air is ejected from the air ejection holes, some negative pressure remains due to the difference in wind speed from the shaping air. Therefore, according to the present invention, since air is ejected in the twist direction opposite to the twist direction of the shaping air, the collision energy with the shaping air drawn into the negative pressure region can be increased. Accordingly, the shaping air can be further suppressed from being drawn into the central negative pressure region, and the coating pattern can be further prevented from being narrowed.
The twist direction of the air ejected from the air ejection hole is also the reverse twist direction with respect to the rebound air generated when the shaping air collides with the object to be coated in the space surrounded by the shaping air. Therefore, the collision energy between the air ejected from the air ejection hole and the rebound air can be increased. Therefore, since the bounce air that is the cause of the negative pressure can be suppressed, the generation of the negative pressure itself can be suppressed. As a result, the shaping air can be further suppressed from being drawn into the central negative pressure region, and the coating pattern can be further suppressed from being narrowed.

  In this case, the air ejection hole is formed so as to eject air to a region (for example, a region T described later) having the largest pressure difference from the rotation shaft in front of the rotary atomizing head. preferable.

  In the present invention, air is ejected toward the region where the pressure difference between the rotary atomizing head and the rotational axis of the rotary atomizing head is greatest in front of the rotary atomizing head. In particular, in the vicinity of the shaping air ejection hole, the shaping air pressure is the highest and the pressure difference with the central portion on the rotating shaft is the largest, so that the force for drawing the shaping air into the central portion is the strongest. Therefore, according to the present invention, since air is ejected toward this region, the pressure difference can be suppressed. As a result, it can suppress that shaping air is drawn in to the center more, and can suppress that a coating pattern becomes narrower.

  In this case, the shaping air ejection hole is formed such that the ejection direction of the shaping air is a twist direction with respect to the rotation axis of the rotary atomizing head, and the air nozzle has the air suction hole, The suction hole is preferably formed so that the air suction direction is the same twist direction as the shaping air twist direction.

  In the present invention, the air suction hole is formed so that the air suction direction is the same twist direction as the shaping air twist direction. Thereby, the twist direction of the air sucked from the air suction hole becomes the twist direction in the same direction with respect to the rebound air generated when the shaping air collides with the object to be coated in the space surrounded by the shaping air. . Therefore, the rebound air can be sucked more smoothly and the negative pressure can be increased. Therefore, the shaping air can be drawn in from the center, and the coating pattern can be further narrowed.

  In this case, the air suction hole may be formed so as to suck air from a region (for example, a region T described later) having the largest pressure difference from the rotation shaft in front of the rotary atomizing head. preferable.

  In the present invention, air is sucked from a region having the largest pressure difference from the rotational axis of the rotary atomizing head in front of the rotary atomizing head. In particular, in the vicinity of the shaping air ejection hole, the shaping air pressure is the highest and the pressure difference with the central portion on the rotating shaft is the largest, so that the force for drawing the shaping air into the central portion is the strongest. Therefore, according to the present invention, since air is sucked toward this region, the pressure difference can be further increased. As a result, the shaping air can be drawn in from the center, and the coating pattern can be further narrowed.

  In this case, the air nozzle has both the air ejection hole and the air suction hole, and paints by controlling and combining the ejection of air from the air ejection hole and the suction of air from the air suction hole. It is preferable to further include air control means (for example, a control device described later) for deforming the pattern.

  In the present invention, the coating pattern is deformed by controlling and combining the ejection of air from the air ejection holes and the suction of air from the air suction holes. For example, by ejecting air from a part in the circumferential direction of the air nozzle and sucking air from the other part, the pressure difference can be unevenly distributed and an asymmetric coating pattern can be formed. Therefore, when coating the end of the article to be coated, a coating pattern corresponding to the shape of the article to be coated can be formed, so that overspray can be suppressed and the coating efficiency can be improved.

Moreover, the electrostatic coating method using an electrostatic coating apparatus provided with a rotary atomization head and the shaping air ejection hole formed surrounding the said rotation atomization head is provided. In the electrostatic coating method according to the present invention, a coating pattern forming air is generated by jetting or sucking air by an air nozzle provided in a central portion of the rotary atomizing head, thereby deforming the coating pattern , Shaping air is ejected in the twisting direction with respect to the rotational axis of the rotary atomizing head by the shaping air ejection hole, and air is ejected in the twisting direction opposite to the twisting direction of the shaping air by the air nozzle. It is characterized by.

  In this case, it is preferable that air is ejected by the air nozzle to a region where the pressure difference from the rotational axis is the largest in front of the rotary atomizing head.

  In this case, it is preferable that air is sucked by the air nozzle from a twist direction that is the same as the twist direction of the shaping air.

  In this case, it is preferable that air is sucked by the air nozzle from a region where the pressure difference from the rotation axis is the largest in front of the rotary atomizing head.

  In this case, it is preferable to deform the coating pattern by controlling and combining the ejection of air by the air nozzle and the suction of air.

  According to the invention of the electrostatic coating method, the same effects as the invention of the electrostatic coating apparatus described above are exhibited.

  ADVANTAGE OF THE INVENTION According to this invention, a desired coating pattern can be formed and the electrostatic coating apparatus and electrostatic coating method which can improve coating efficiency can be provided.

It is a perspective view which shows schematic structure of the electrostatic coating apparatus which concerns on 1st Embodiment. It is a side view of the electrostatic coating apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the structure of the front-end | tip part of the electrostatic coating apparatus which concerns on 1st Embodiment. It is a figure for demonstrating the structure of the electrostatic coating apparatus which concerns on 1st Embodiment, (A) is a perspective view of an air nozzle, (B) is the figure which looked at the head part from the front end side. It is a figure which shows the flow direction of shaping air, and the flow direction of rebound air. It is a figure for demonstrating the structure of the electrostatic coating apparatus which concerns on 2nd Embodiment, (A) is a perspective view of an air nozzle, (B) is the figure which looked at the head part from the front end side. It is the figure which looked at the head part of the electrostatic coating apparatus which concerns on 3rd Embodiment from the front end side. It is a figure which shows the coating pattern of the electrostatic coating apparatus which concerns on 3rd Embodiment, (A) is a coating pattern when only air ejection is performed over the perimeter, (B) is over the perimeter. A coating pattern when only air suction is performed, (C) is a diagram showing a coating pattern when air ejection and air suction are performed half a cycle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description after the first embodiment, the same reference numerals are given to the components common to the first embodiment, and the description thereof is omitted.

[First Embodiment]
The electrostatic coating apparatus 1 according to the first embodiment of the present invention is an electrostatic coating apparatus that can form a desired coating pattern and can improve the coating efficiency, and can perform the electrostatic coating method of the present invention. Yes. Here, in the present specification, the “coating pattern” means a coating film portion having a film thickness up to ½ of the maximum film thickness in the coating film.

FIG. 1 is a perspective view showing a schematic configuration of an electrostatic coating apparatus 1 according to the first embodiment of the present invention. FIG. 2 is a side view of the electrostatic coating apparatus 1.
The electrostatic coating apparatus 1 electrostatically coats a body 2 of an automobile, has a cylindrical body portion 10 attached to the tip of a robot arm 3, a substantially U-shape with a bent tip portion, and And a head portion 20 detachably provided at the tip of the body portion 10.

FIG. 3 is a cross-sectional view showing the configuration of the tip portion of the head unit 20.
The head unit 20 includes an air motor (not shown), a rotary atomizing head 22 that is rotationally driven by the air motor, an air nozzle 21 provided in the center of the rotary atomizing head 22, and paint and cleaning liquid on the rotary atomizing head 22. A supply pipe 11 that supplies air to the air nozzle 21, an air cap 40 that surrounds the rotary atomizing head 22, and a high voltage (not shown) that applies a high voltage to the rotary atomizing head 22 to charge the paint to a high voltage. A voltage generator.

  The rotary atomizing head 22 has a substantially conical shape having an inner diameter that increases toward the distal end side, and is provided at the distal end of the head portion 20. The rotary atomizing head 22 is rotatably provided with the rotation axis X as a rotation axis.

  The rotary atomizing head 22 is provided with a cylindrical rotating part 23 in which the supply pipe 11 is housed, and is provided at the tip of the rotating part 23 so as to surround the tip of the supply pipe 11 and expand in the injection direction. The expansion part 24 and the substantially disk-shaped obstruction | occlusion part 25 which is provided in the front end side of the supply pipe | tube 11 and block | closes the inner wall face of the expansion part 24 are provided.

  The rotating part 23 includes a cylindrical rotating part main body 231 and a substantially disk-shaped tip part 232 that closes the tip of the rotating part main body 231. An expanding portion 24 is screwed to the rotating portion 23. A through hole 233 into which an air supply pipe 111, a paint supply pipe 112, and a cleaning liquid supply pipe 113, which will be described later, are inserted, is formed substantially at the center of the distal end portion 232.

  The supply pipe 11 is inserted through the rotating portion 23, and the distal end of the supply pipe 11 is inserted through the through hole 233 of the distal end portion 232. The periphery of the through hole 233 of the distal end portion 232 is recessed, and this recessed portion is a paint reservoir 234 in which paint is accumulated. Moreover, the space obstruct | occluded by the inner wall face of the expansion part 24 and the obstruction | occlusion part 25 becomes the atomization chamber 26 for giving a centrifugal force to a coating material.

  A plurality of peripheral edge through-holes 252 that penetrate the front and back surfaces along the inner wall surface of the expanding portion 24 and communicate the inside and the outside of the atomizing chamber 26 are formed in the peripheral portion of the closing portion 25. . Further, a central portion through hole 251 is formed in the central portion of the closing portion 25 through which an air supply pipe 111 described later is inserted.

The supply pipe 11 has a triple pipe structure including an air supply pipe 111, a paint supply pipe 112, and a cleaning liquid supply pipe 113.
The base end of the air supply pipe 111 is connected to an air compressor as an air supply source (not shown) via a flow rate control valve (not shown). The tip of the air supply pipe 111 extends to an air nozzle 21 described later and faces the buffer chamber 213.
The base ends of the paint supply pipe 112 and the cleaning liquid supply pipe 113 are connected to a paint supply source and a cleaning liquid supply source (not shown), respectively. The tips of the paint supply pipe 112 and the cleaning liquid supply pipe 113 extend to the rotary atomizing head 22 and face the atomizing chamber 26.

  The air nozzle 21 is provided in the center of the rotary atomizing head 22. The air nozzle 21 is fixed to the air supply pipe 111 with a fastening member such as a screw. The air nozzle 21 has a substantially cylindrical shape, and is formed so that the outer diameter increases toward the tip side.

  A buffer chamber 213 is formed inside the air nozzle 21. In addition, a concave portion 211 that is recessed toward the proximal end is formed at the center of the distal end surface 210 of the air nozzle 21. Moreover, the outer peripheral part of the front end surface 210 of the air nozzle 21 is a flat surface, and a plurality of air ejection holes 212 are annularly formed in the outer peripheral part along the circumferential direction. From the plurality of air ejection holes 212, air is ejected in a twist direction opposite to the twist direction of the shaping air.

  The air cap 40 is attached to a housing (not shown). The air cap 40 is formed so as to surround the rotary atomizing head 22, and a front end surface 400 of the air cap 40 is behind the front end edge of the rotary atomizing head 22 with respect to the spray direction of the paint. It is located in the middle of the rotary atomizing head 22.

  The front end surface 400 of the air cap 40 is provided with a plurality of shaping air ejection holes 41 formed so as to surround the rotary atomizing head 22. From this shaping air ejection hole 41, shaping air is ejected in a twist direction opposite to the rotation direction of the rotary atomizing head 22.

  A plurality of shaping air passages 411 communicating with the shaping air ejection hole 41 are provided inside the air cap 40. The plurality of shaping air passages 411 are connected to an air compressor as an air supply source (not shown) via a flow rate control valve (not shown).

FIG. 4 is a view for explaining the configuration of the electrostatic coating apparatus 1 according to the present embodiment. FIG. 4A is a perspective view of the air nozzle 21. In FIG. 4A, the concave portion 211 is omitted for convenience.
As shown in FIG. 4A, each of the plurality of air ejection holes 212 formed in the air nozzle 21 extends from the buffer chamber 213 and reaches the tip surface 210 of the air nozzle 21. Each of the plurality of air ejection holes 212 is formed so as to be inclined in the circumferential direction, specifically, the rotational direction of the rotary atomizing head 22 (the direction of arrow R in FIG. 4). That is, each of the plurality of air ejection holes 212 is inclined in the rotational direction of the rotary atomizing head 22 toward the distal end side. Thereby, the air ejected from the plurality of air ejection holes 212 is ejected with respect to the rotational axis X in the twist direction in the same direction as the rotational direction of the rotary atomizing head 22.
In the present embodiment, the inclination angles in the rotational direction of the plurality of air ejection holes 212 are all the same, but are not limited thereto. Note that this inclination angle represents the twist (torsion) angle of air with respect to the rotation axis X.

Further, each of the plurality of air ejection holes 212 is formed to be inclined in the radial direction, specifically, radially outward. That is, each of the plurality of air ejection holes 212 is inclined outward in the radial direction toward the distal end side. As a result, air can be ejected toward the vicinity of a shaping air ejection hole (region T described later) having the largest pressure difference.
In the present embodiment, the radially outward inclination angles of the plurality of air ejection holes 212 are all the same, but are not limited thereto.

FIG. 4B is a view of the head unit 20 as viewed from the front end side. As shown in FIG. 4B, in this embodiment, the shaping air ejected from the shaping air ejection hole 41 is ejected in a twist direction opposite to the rotation direction R of the rotary atomizing head 22. Further, the air ejected from the air ejection holes 212 is ejected in the twist direction opposite to the twist direction of the shaping air.
In the present embodiment, the twisting angle of the shaping air ejected from the shaping air ejection hole 41 and the twisting angle of the air ejected from the air ejection hole 212 are set to be the same.

Here, the ejection direction of air from the air ejection holes 212 will be described in more detail.
FIG. 5 is a diagram illustrating the flow direction of the shaping air A1 and the flow direction of the rebound air A2. More specifically, FIG. 5 shows the shaping air when the shaping air A1 is ejected from the shaping air ejection hole 41c to the paint atomized from the rotary atomizing head 22c included in the head portion 20c of the conventional electrostatic coating apparatus. The flow direction of A1 and the flow direction of the rebound air A2 are shown.
The rebound air A2 is air that is generated when the shaping air A1 collides with the workpiece W as the object to be coated in the space surrounded by the shaping air A1, and flows from the front end side toward the base end side.

  Thus, the rebound air A2 is generated by the ejection of the shaping air A1, and the rebound air A2 generates a negative pressure, which causes the coating pattern to narrow. Therefore, in the present embodiment, air that cancels the rebound air A <b> 2 is ejected from the air ejection hole 212.

  Further, as shown in FIG. 5, in the region T in the vicinity of the shaping air ejection hole 41c, the shaping air pressure is the highest and the pressure difference with the central portion on the rotation axis X is the largest. The power to pull in is the strongest. In the region T, it is known that the swirl velocity component is the largest and the flow in the direction of the rotation axis X is a vortex. Therefore, in the present embodiment, air is ejected toward the region T where the pressure difference between the rotary atomizing head 22c and the rotation axis X is the largest, in order to reduce the pressure difference.

The electrostatic coating apparatus 1 according to the present embodiment operates as follows.
First, the paint is discharged from the paint supply pipe 112 to the atomization chamber 26 while the rotary atomizing head 22 is rotated at a high speed. Then, since the rotary atomizing head 22 is rotating at high speed, a centrifugal force acts on the discharged paint and moves toward the peripheral portion of the closed portion 25 along the inner surface of the closed portion 25. .

  The paint that has reached the peripheral edge of the blocking portion 25 passes through the peripheral edge through hole 252 and moves to the outside of the atomization chamber 26. Further, it moves along the inner wall surface of the expanded portion 24 toward the outer edge at the tip of the expanded portion 24. As the outer edge portion of the spreading portion 24 approaches, the centrifugal force acting on the paint increases, and the paint is separated into a large number of fine droplets and forms a mist. This mist-like paint scatters from the outer edge part of the expansion part 24.

  At this time, shaping air is ejected from the shaping air ejection hole 41 toward the outer edge of the rotary atomizing head 22. More specifically, the shaping air is ejected in the twist direction opposite to the rotation direction of the rotary atomizing head 22 with respect to the rotation axis X. As a result, the atomized paint is directed in the direction of the object.

  At this time, air is ejected from the air nozzle 21 in a twist direction opposite to the twist direction of the shaping air. Thereby, it is suppressed that shaping air is drawn in to a center part, and a desired painting pattern is secured.

According to the electrostatic coating apparatus 1 according to the present embodiment, the following effects are exhibited.
In the present embodiment, an air nozzle 21 is provided in the central portion of the rotary atomizing head 22, and a plurality of air ejection holes 212 that generate coating pattern forming air by ejecting air are formed in the air nozzle 21. Thereby, by ejecting air from the plurality of air ejection holes 212, the negative pressure generated at the front center of the rotary atomizing head 22 due to the ejection of shaping air can be sufficiently suppressed, and the size of the coating pattern can be set to a desired size. Can be spread. As described above, according to the present embodiment, the coating pattern forming air can be generated by ejecting or sucking air from the central portion of the rotary atomizing head 22, and the desired coating pattern can be controlled by controlling the flow rate thereof. Therefore, the coating efficiency can be improved.

In the present embodiment, the air ejection holes 212 are formed so that the air ejection direction is the reverse twist direction of the shaping air. Here, even when air is ejected from the air ejection holes 212, some negative pressure remains due to the difference in wind speed with the shaping air. Therefore, according to the present embodiment, since air is ejected in the twist direction opposite to the twist direction of the shaping air, the collision energy with the shaping air drawn into the negative pressure region can be increased. Accordingly, the shaping air can be further suppressed from being drawn into the central negative pressure region, and the coating pattern can be further prevented from being narrowed.
Further, the twist direction of the air ejected from the air ejection hole 212 is the reverse twist direction with respect to the rebound air generated when the shaping air collides with the object to be coated in the space surrounded by the shaping air. . Therefore, the collision energy between the air ejected from the air ejection hole 212 and the rebound air can be increased. Therefore, since the bounce air that is the cause of the negative pressure can be suppressed, the generation of the negative pressure itself can be suppressed. As a result, the shaping air can be further suppressed from being drawn into the central negative pressure region, and the coating pattern can be further suppressed from being narrowed.

  Further, in the present embodiment, air is ejected toward the region T where the pressure difference between the rotary atomizing head 22 and the rotation axis X is the largest in front of the rotary atomizing head 22. In particular, in the vicinity of the shaping air ejection hole 41, the shaping air pressure is the highest and the pressure difference with the central portion on the rotation axis X is the largest, so that the force for drawing the shaping air into the central portion is the strongest. Therefore, according to the present embodiment, since air is ejected toward the region T, the pressure difference can be suppressed. As a result, it can suppress that shaping air is drawn in to the center more, and can suppress that a coating pattern becomes narrower.

[Second Embodiment]
The present embodiment is different from the first embodiment in that a plurality of air suction holes 214 are provided instead of the plurality of air ejection holes 212, and a suction pump is connected to the plurality of air suction holes 214 instead of the air compressor. Other than that, the configuration is the same as that of the first embodiment.
6A and 6B are diagrams for explaining the configuration of the electrostatic coating apparatus according to the second embodiment. FIG. 6A is a perspective view of an air nozzle, and FIG. It is a figure.

As shown in FIG. 6A, each of the plurality of air suction holes 214 formed in the air nozzle 21a extends from the buffer chamber 213 and reaches the tip surface 210 of the air nozzle 21a. Further, each of the plurality of air suction holes 214 is formed to be inclined in the opposite direction with respect to the circumferential direction, specifically, the rotation direction of the rotary atomizing head 22 (the direction of arrow R in FIG. 4). . That is, each of the plurality of air suction holes 214 is inclined in a direction opposite to the rotation direction of the rotary atomizing head 22 toward the distal end side. Thereby, the air sucked from the plurality of air suction holes 214 is sucked from the twist direction opposite to the rotation direction of the rotary atomizing head 22 with respect to the rotation axis X.
In the present embodiment, the inclination angles in the rotation direction of the plurality of air suction holes 214 are all the same, but are not limited thereto.

The plurality of air suction holes 214 are formed to be inclined in the radial direction, specifically, radially outward. That is, each of the plurality of air suction holes 214 is inclined outward in the radial direction toward the distal end side. Thereby, air can be sucked from the vicinity of the shaping air ejection hole 41 having the largest pressure difference.
In the present embodiment, the radially outward inclination angles of the plurality of air suction holes 214 have the same magnitude, but are not limited thereto.

FIG. 6B is a view of the head portion 20a as viewed from the front end side. As shown in FIG. 6B, in this embodiment, the shaping air ejected from the shaping air ejection hole 41 is ejected in a twist direction opposite to the rotation direction R of the rotary atomizing head 22. Further, the air sucked from the air suction hole 214 is sucked from the twist direction that is the same as the twist direction of the shaping air.
In the present embodiment, the twisting angle of the shaping air ejected from the shaping air ejection hole 41 and the twisting angle of the air sucked from the air suction hole 214 are set to be the same.

According to the electrostatic coating apparatus according to the present embodiment, the following effects are exhibited.
In the present embodiment, the air suction hole 214 is formed so that the air suction direction is the same twist direction as the shaping air twist direction. Thus, the twist direction of the air sucked from the air suction hole 214 is the same as the twist direction in the space surrounded by the shaping air with respect to the rebound air generated when the shaping air collides with the object to be coated. Become. Therefore, the rebound air can be sucked more smoothly and the negative pressure can be increased. Therefore, the shaping air can be drawn in from the center, and the coating pattern can be further narrowed.

  In the present embodiment, air is sucked from a region where the pressure difference between the rotary atomizing head 22 and the rotation axis X is the largest in front of the rotary atomizing head 22. In particular, in the vicinity of the shaping air ejection hole 41, the shaping air pressure is the highest and the pressure difference with the central portion on the rotation axis X is the largest, so that the force for drawing the shaping air into the central portion is the strongest. Therefore, according to the present embodiment, since air is sucked toward this region, the pressure difference can be further increased. As a result, the shaping air can be drawn in from the center, and the coating pattern can be further narrowed. Therefore, the electrostatic coating apparatus according to the present embodiment is particularly preferably used when coating an elongated work such as a pillar.

[Third Embodiment]
In the present embodiment, in addition to the plurality of air ejection holes 212b, a plurality of air suction holes 214b and suction pumps connected thereto are provided, and the air ejection from the air ejection holes 212b and the air suction holes 214b are provided. The point which provided the air control apparatus which controls the attraction | suction of this air is different from 1st Embodiment, and it is the structure similar to 1st Embodiment other than that.
FIG. 7 is a view of the head portion 20b of the electrostatic coating apparatus according to the third embodiment as viewed from the front end side.

As shown in FIG. 7, a plurality of air ejection holes 212b are formed along the circumferential direction at the peripheral edge of the air nozzle 21b. A plurality of air suction holes 214b are formed inside the plurality of air ejection holes 212b. The configuration of the plurality of air ejection holes 212b is the same as the plurality of air ejection holes 212 of the first embodiment, and the configuration of the plurality of air suction holes 214b is the same as the plurality of air suction holes 214 of the second embodiment. is there.
Thereby, the air ejected from the plurality of air ejection holes 212b is ejected in a twist direction opposite to the twist direction of the shaping air. In addition, the air sucked from the air suction hole 214b is sucked from the twist direction that is the same as the twist direction of the shaping air.

  An air control device (not shown) controls the ejection of air from the air ejection holes 212b and the suction of air from the air suction holes 214b. For example, as shown in FIG. 7, in the half circumferential portion in the circumferential direction, air is ejected from the air ejection hole 212b, while the control valve provided between the suction pump and the air suction hole 214b is shut off. Stop air suction. Further, in the remaining half-circumferential portion, air is sucked from the air suction hole 214b, while the control valve provided between the air compressor and the air compressor is shut off to stop the air ejection from the air ejection hole 212b.

According to the electrostatic coating apparatus according to the present embodiment, the following effects are exhibited.
In the present embodiment, the coating pattern is deformed by controlling and combining the ejection of air from the air ejection holes 212b and the suction of air from the air suction holes 214b. For example, by ejecting air from a part of the air nozzle 21b in the circumferential direction and sucking air from the other part, the pressure difference can be unevenly distributed and an asymmetric coating pattern can be formed.

Here, FIG. 8 is a figure which shows the coating pattern of the electrostatic coating apparatus which concerns on this embodiment, (A) is a coating pattern when performing only air ejection over the perimeter, (B) is The coating pattern when only air suction is performed over the entire circumference, (C) is a diagram showing the coating pattern when air ejection and air suction are performed half a cycle at a time.
As shown in FIG. 8, a large coating pattern is obtained as in the first embodiment by performing only air ejection over the entire circumference, and the second implementation is performed by performing only air suction over the entire circumference. A small paint pattern like a form is obtained. Moreover, an asymmetric coating pattern can be obtained by performing air ejection and air suction for each half circumference. Therefore, the present embodiment is preferably used because a coating pattern corresponding to the shape of the object to be coated can be formed particularly when the end portion of the object to be coated is painted. Thereby, overspray can be suppressed and the coating efficiency can be improved.

  The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

DESCRIPTION OF SYMBOLS 1 ... Electrostatic coating apparatus 21 ... Air nozzle 22 ... Rotary atomization head 41 ... Shaping air ejection hole 212 ... Air ejection hole 214 ... Air suction hole X ... Rotating shaft

Claims (10)

A rotating atomizing head that charges and atomizes the paint by rotating in a state where a high voltage is applied,
An electrostatic coating apparatus comprising: a shaping air ejection hole that is formed surrounding the rotary atomizing head and ejects shaping air that directs the atomized paint in a direction of an object to be coated,
A plurality of air ejection holes that are provided in the center of the rotary atomizing head and that generate paint pattern forming air by blowing air and a plurality of air suctions that generate paint pattern forming air by sucking the air An air nozzle having at least one of the holes ;
The shaping air ejection hole is formed such that the ejection direction of the shaping air is a twist direction with respect to the rotation axis of the rotary atomizing head,
The air nozzle has the plurality of air ejection holes,
The electrostatic spraying device is characterized in that the air ejection hole is formed so that an air ejection direction is a twist direction opposite to a twist direction of the shaping air . The electrostatic coating apparatus according to claim 1 ,
The electrostatic coating apparatus, wherein the air ejection hole is formed so that air is ejected to a region where the pressure difference with the rotation axis is the largest in front of the rotary atomizing head. In the electrostatic coating apparatus according to claim 1 or 2 ,
The shaping air ejection hole is formed such that the ejection direction of the shaping air is a twist direction with respect to the rotation axis of the rotary atomizing head,
The air nozzle has the plurality of air suction holes,
The electrostatic coating apparatus is characterized in that the air suction hole is formed so that the air suction direction is the same twist direction as the shaping air twist direction. In the electrostatic coating apparatus according to claim 3 ,
The electrostatic coating apparatus, wherein the air suction hole is formed so as to suck air from a region having a largest pressure difference from the rotary shaft in front of the rotary atomizing head. In the electrostatic coating apparatus in any one of Claim 1 to 4 ,
The air nozzle has both the plurality of air ejection holes and the plurality of air suction holes,
An electrostatic coating apparatus, further comprising air control means for deforming a coating pattern by controlling and combining the ejection of air from the air ejection holes and the suction of air from the air suction holes. An electrostatic coating method using an electrostatic coating apparatus comprising: a rotary atomizing head; and a shaping air ejection hole formed surrounding the rotary atomizing head,
The air nozzle provided in the central portion of the rotary atomizing head generates the paint pattern forming air by ejecting or sucking air, thereby deforming the paint pattern ,
With the shaping air ejection hole, shaping air is ejected in a twisting direction with respect to the rotation axis of the rotary atomizing head,
An electrostatic coating method characterized in that air is ejected in a twist direction opposite to a twist direction of shaping air by the air nozzle. In the electrostatic coating method of Claim 6 ,
An electrostatic coating method characterized in that air is ejected to a region having the largest pressure difference with respect to the rotary shaft in front of the rotary atomizing head by the air nozzle. In the electrostatic coating method according to claim 6 or 7 ,
An electrostatic coating method comprising sucking air from a twist direction that is the same as a twist direction of shaping air by the air nozzle. In the electrostatic coating method of Claim 8 ,
An electrostatic coating method, wherein air is sucked from an area where the pressure difference from the rotation axis is the largest in front of the rotary atomizing head by the air nozzle. In the electrostatic coating method in any one of Claim 6 to 9 ,
An electrostatic coating method, wherein a coating pattern is deformed by controlling and combining air ejection and air suction by the air nozzle.

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