JPH06134352A - Electrostatic coater - Google Patents

Abstract

PURPOSE:To improve the working efficiency of coating operation, coating quality, etc., by preventing the adhesion of the coating materials sprayed from a rotary atomizing head to a casing. CONSTITUTION:This electrostatic coater is constituted by disposing L-shaped electrode supporting arms 22 of one piece each in an up direction and down direction, respectively along the forward and backward moving directions of a coating machine 21 consisting of a vertically moving reciprocator 11, disposing the remaining electrode supporting arms 22 apart 30 deg. each circumferentially between the respective electrode supporting arms in the forward and backward moving directions and providing the respective electrode supporting arms 22 with external electrodes 24 via supporters 23. As a result, the coating materials splashing in a vertical direction among the coating materials sprayed toward the outer side in the diametral direction from the rotary atomizing head are effectively electrified by the respective external electrodes 24 disposed in the up direction and the down direction and the influence of the inertial force according to the forward and backward movement of the coating machine 21 on these materials is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic coating apparatus suitable for coating an object to be coated such as a car body, and in particular, a plurality of external electrodes are provided outside a rotary atomizing head. Electrostatic coating equipment.

[0002]

2. Description of the Related Art Generally, there are two types of paints used for painting objects to be coated, such as vehicle bodies, such as solvent-based paints having high electric resistance, and water-based paints and metallic paints having low electric resistance. In the case of an electrostatic coating device using a system-based paint, a high voltage cannot be directly applied to the rotary atomizing head, so a plurality of external electrodes are arranged on the outer side in the radial direction of the rotary atomizing head so as to be spaced apart in the circumferential direction. By indirectly charging the paint particles atomized by the rotary atomizing head by each external electrode, the paint particles are caused to fly toward the object to be coated, which is the ground potential.

Therefore, as an electrostatic coating apparatus according to the prior art, an electrostatic coating apparatus in which a vertically moving reciprocator is provided with a rotary atomizing type coating machine is shown in FIGS.

In the drawing, 1 is a rotary atomizing type coating machine, and 2 is
Indicates respective casings constituting the coating machine 1, and the casing 2 is formed in a cylindrical shape from an insulating resin material such as polytetrafluoroethylene, and has a rotary atomizing head 3 to be described later on its tip side. A shaping ring 2A for ejecting shaping air for pushing the atomized paint forward is provided. Further, inside the casing 2, an air motor having an air bearing, a rotary shaft rotatably driven by the air motor, and a paint pipe line for supplying paint from the color changing valve device to the rotary atomizing head 3. , And an air conduit (not shown) for supplying air to the shaping ring 2A.

Reference numeral 3 denotes a cup-shaped rotary atomizing head rotatably provided on the tip side of the casing 2, and the rotary atomizing head 3
Is connected to the rotating shaft in the casing 2. And
The rotary atomizing head 3 is rotated at a high speed by the rotating force of the rotating shaft to atomize the water-based paint and the metallic paint supplied through the paint pipe and spray them in the radial direction by centrifugal force. .

[0006] The electrodes 4, 4, ... are arranged on the base end side of the casing 2 at intervals of 60 degrees in the circumferential direction, and are formed into six L-shaped electrodes made of the same insulating resin material as the casing 2. As shown in FIG. 6, each electrode support arm 4 extends from the base end side of the casing 2 toward the outer side in the radial direction.
Each of the electrode support arms 4 is composed of a fixed portion 4A fixed to the casing 2 by mounting bolts 5 and 5, and a holding portion 4B extending from the tip side of the fixed portion 4A toward the rotary atomizing head 3 side. A high-voltage connecting portion (not shown) made of a metal wire or the like for supplying a predetermined high voltage supplied from the high-voltage generating device via the connector 6 to each external electrode 8 described later is arranged therein. It is set up.

.. are holding portions 4B of the electrode supporting arms 4.
The supporters 8, 8, ..., Which are respectively fitted to the tip side and formed in the shape of a small-diameter cylinder from an insulating resin material, are the supporters 7.
Each of the external electrodes 8 is embedded in the center of the axis, and each of the external electrodes 8 is connected at its base end side to a high voltage generator through a high voltage connecting portion in each electrode support arm 4 and a connector 6,
The tip side thereof slightly projects from the tip side of each supporter 7. Then, a high voltage of −50 to −90 kV is applied to each of the external electrodes 8 by the high voltage generator,
A corona discharge region is formed in front of the tip side of the rotary atomizing head 3 to charge the paint particles that are traced in amount.

Reference numeral 9 denotes an object to be coated such as an iron plate movably provided in front of the coating machine 1. The object 9 to be coated is shown in FIG. 5 by a hanger 10 connected to a conveyor (not shown). It is moved at a predetermined speed in the direction perpendicular to the paper surface and is at the ground potential.

Reference numeral 11 denotes a vertically moving reciprocator as a reciprocating means for reciprocating the coating machine 1 in the vertical direction. The reciprocator 11 has a support portion 11A fixed to the floor.
The movable portion 11C is generally constituted by a movable portion 11C that is vertically movable in a guide groove 11B of the support portion 11A.
A mounting bracket 11D that is mounted on the base end side of the coating machine 1 via the insulating support portion 12 is provided on the tip end side of the. The vertical reciprocating locator 11 is used in the coating machine 1.
By reciprocating up and down while supporting, the surface of the article to be coated 9 that moves perpendicular to the paper surface is painted.

The electrostatic coating device according to the prior art has the above-described structure. First, the rotary atomizing head 3 is rotated at a high speed of about 40,000 to 60,000 rpm by the rotation of the air motor, and the high voltage generator is connected to the connector 6 or the like. A predetermined high voltage is applied to each of the external electrodes 8 via the electrodes to form a corona discharge region in front of each of the external electrodes 8. Next, when the paint is supplied from the color changing valve device to the rotary atomizing head 3 through the paint conduit, the paint is atomized by the rotary atomizing head 3 and a predetermined height is reached while passing through the corona discharge region. By being charged with a voltage, it flies along the lines of electric force between the article 9 to be coated and adheres to the surface of the article 9 to be coated. On the other hand, the vertical reciprocator 11 causes the coating machine 1 to reciprocate up and down according to the conveying speed of the article 9 to be coated, the coating thickness, etc., and the surface of the article 9 to be coated is coated by the coating machine 1.

[0011]

By the way, in the electrostatic coating apparatus according to the above-mentioned prior art, by disposing the six external electrodes 8 at the base end side of the casing 2 in the circumferential direction, the centrifugal force is increased. The paint particles sprayed in the radial direction from the rotary atomizing head 3 are indirectly charged and fly along the lines of electric force.

However, as shown in FIG. 6, although the paint flying toward each external electrode 8 is immediately charged and flies toward the article 9 to be coated, the space between each external electrode 8 is charged with a low voltage. Since it is difficult to do so, the paint sprayed between the external electrodes 8 is not sufficiently charged and is strongly affected by the centrifugal force and spreads outward in the radial direction. Therefore, the spray pattern of the paint is indicated by a chain double-dashed line in FIG. As shown, it becomes petal-shaped with irregularities in the circumferential direction. In particular,
Since the coating machine 1 is reciprocated up and down by the vertical reciprocating device 11, the spray pattern of the paint is disturbed by the inertial force and the like accompanying the reciprocating motion, and the coating pattern is moved along the moving direction of the coating machine 1. Easy to spread upward and downward.

For this reason, in the above-mentioned prior art, not only the paint particles flying between the external electrodes 8 float on the tip side of the casing 2 to lower the coating efficiency, but also the casing as shown in FIG. 2 is gradually adhered and accumulated along the movement direction (vertical direction) of the coating machine 1 to the adhered paints P, P, and the adhered paint P adheres to the object 9 to be coated during the coating and the coating quality. There is a problem in that Further, in order to prevent the deterioration of the coating quality, it is necessary to frequently clean the coating machine 1 to remove the adhering coating material P, so that the work efficiency of the coating work, the productivity, etc. are significantly lowered. There's a problem.

On the other hand, in order to solve such a problem, the number of external electrodes is increased to, for example, about 20 to 30 to eliminate the strength of the electric power due to each external electrode and to apply the atomized paint. A method of causing an object to fly is also conceivable.
However, in this case, not only is the overall structure complicated and maintenance is poor, but since the voltage from the high-voltage generator is distributed to each external electrode, the electrification power per external electrode decreases and charging There is a problem that efficiency is significantly reduced.

The present invention has been made in view of the above-mentioned problems of the prior art. It is possible to effectively prevent the paint sprayed from the rotary atomizing head from adhering to the casing. An object of the present invention is to provide an electrostatic coating device capable of improving coating quality and the like.

[0016]

In order to solve the above-mentioned problems, the structure adopted by the present invention has a cylindrical casing and a rotatably provided at the tip end side of the casing, and is supplied through the casing. A rotary atomizing head for atomizing the formed paint, and a radial outer side of the rotary atomizing head, which is provided on the base end side of the casing and is circumferentially separated from the rotary atomizing head. A plurality of external electrodes that charge the converted paint,
Reciprocating means for coating the article by reciprocating the casing in a predetermined direction with respect to the article to be coated, wherein each of the external electrodes is a forward or backward direction of the casing by the reciprocating means. One for each,
The remaining external electrodes are located between the pair of external electrodes in the reciprocating direction and are arranged at a predetermined angle in the circumferential direction.

[0017]

When the paint is sprayed from the rotary atomizing head to the outside in the radial direction, the paint sprayed along the reciprocating direction of the casing is disposed in the forward and backward directions of the casing. The paint charged by the external electrodes and sprayed in a direction other than the reciprocating direction of the casing is charged by other electrodes, which reduces the influence of the inertial force that accompanies the reciprocating movement of the casing, resulting in a spray pattern of the paint. Be homogenized.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the conventional technique shown in FIGS. 5 and 6 described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 21 denotes a coating machine according to this embodiment, which is composed of a casing 2, a rotary atomizing head 3 and the like, and is moved up and down in the same manner as the coating machine 1 described in the prior art. Although being supported by the reciprocator 11, the coating machine 21 includes an external electrode 24, which will be described later.
1 is arranged along the reciprocating direction.

Reference numerals 22, 22, ... Denote electrode support arms made of an insulating resin applied to this embodiment in place of the electrode support arms 4 described in the prior art. The electrode support arms 22 are described in the prior art. Similar to each of the electrode support arms 4, a total of 6 are arranged on the base end side of the casing 2 at intervals of 60 degrees in the circumferential direction, and are formed in an L shape from the fixing portion 22A and the holding portion 22B. There is. However, each electrode support arm 22 is
Along the reciprocating direction of the coating machine 21 by the up-and-down motion reciprocator 11, one is provided in each of the upward direction as the forward path and the downward direction as the return path, and the remaining four are between the electrode support arms 22 in the reciprocating direction. It is different from each electrode supporting arm 4 according to the conventional technique in that it is located at a distance of 30 degrees in the circumferential direction.

, 23, 23, ... Supporters 24, 2 made of insulating resin fitted to the holding portions 22B of the electrode supporting arms 22.
4, external electrodes embedded in the axial center of each supporter 23 are respectively formed, and each external electrode 24 is configured in the same manner as each external electrode 8 described in the prior art and is connected to a high voltage generator. There is.

The electrostatic coating apparatus according to this embodiment has the above-mentioned structure, and its basic operation is not different from that of the prior art.

However, in this embodiment, one L-shaped electrode support arm 22 is provided in each of the upward and downward directions along the reciprocating direction of the coating machine 21 by the vertically moving reciprocator 11.
And the remaining electrode support arms 22 are arranged at intervals of 30 degrees in the circumferential direction between the electrode support arms 22 in the reciprocating direction.
The external electrodes 2 are attached to the respective electrode support arms 22 via the supporters 23.
4 is provided, the vertical reciprocator 11
Each external electrode 24 along the reciprocating direction of the coating machine 21 by
Of the paint sprayed from the rotary atomizing head 3 toward the outer side in the radial direction, the paint splashed in the vertical direction is effectively provided by the external electrodes 24 arranged in the upward and downward directions. Can be charged to.

As a result, it is possible to effectively prevent the paint sprayed in the reciprocating direction of the coating machine 21 from spreading outward under the influence of the inertial force caused by the reciprocating movement of the coating machine 21. The spray pattern can be made uniform as indicated by the chain double-dashed line in the inside, and the sprayed paint from the rotary atomizing head 3 is prevented from floating and adhering to the tip side of the casing 2. It is possible to significantly improve the work efficiency and the like.

In the above embodiment, the vertical reciprocator 1 for moving the coating machine 21 up and down as the reciprocating means.
However, the present invention is not limited to this, and a pair of support portions 32A and 32A that are erected on both sides of the conveyor 31 are provided, for example, as in the first modification shown in FIG.
And a guide portion 3 provided on the upper end side of each support portion 32A.
By reciprocating the coating machine 21 in the left-right direction in FIG. 3 using the gate type reciprocator 32 composed of 2B and the like,
You may coat the to-be-coated material 33, such as a vehicle body, conveyed by the conveyance conveyor 31 in a direction perpendicular to the paper surface. In this case, six external electrodes 24 are arranged along the left and right reciprocating directions, that is, one external electrode 24 is arranged in each of the left and right directions, and the remaining four external electrodes 24 are arranged in the left and right directions. Direction external electrode 2
It suffices that they are located between the four and are spaced apart by about 30 degrees in the circumferential direction.

Further, as another modification shown in FIG. 4, as a reciprocating means, for example, a base 41A, a swivel base 41B provided on the base 41A so as to swivel horizontally, and the swivel base. 41B provided on the first arm portion 41C, a second arm portion 41D rotatably provided on the tip end side of the first arm portion 41C, and a tip end side of the second arm portion 41D. A support unit (not shown) is reciprocated in a desired direction by using a robot 41 including a wrist unit 41E that is provided so as to be rotatable in a horizontal direction orthogonal to the axis of the second arm unit 41D. The coating object 42, such as an iron plate, supported via the may be applied. In this case, according to the painting direction or the like predetermined by the painting program, the wrist 41
By rotating E by a predetermined angle, the external electrodes 24 are positioned one by one at both ends of the diagonal direction when the coating machine 21 moves in the diagonal direction along the reciprocating direction of the coating machine 21. The wrist portion 41E may be rotated in this manner.

Further, in the above embodiment, the case where six external electrodes 24 are used has been described as an example, but the present invention is not limited to this, and for example, four or eight or more external electrodes may be used. Good.

On the other hand, in the above-mentioned embodiment, the external electrode 24 is attached via the L-shaped electrode support arm 22 arranged on the base end side of the casing 2. However, instead of this,
A ring-shaped electrode mounting portion may be provided outside the casing, and the external electrode may be disposed via the electrode mounting portion.

[0029]

As described above in detail, according to the present invention, one external electrode is provided in each of the forward and backward directions of the casing by the reciprocating means, and the remaining external electrodes are provided in the forward and backward directions. When the paint is sprayed radially outward from the rotary atomizing head, it is located between the pair of external electrodes and is spaced apart by a predetermined angle in the circumferential direction. The paint sprayed on the casing is charged by the external electrodes arranged in the forward and backward directions of the casing, and the paint sprayed in a direction other than the reciprocating direction of the casing is charged by the other external electrodes.

As a result, the influence of the inertial force associated with the reciprocating movement of the casing is reduced, the spray pattern of the paint is made uniform, and the paint sprayed from the rotary atomizing head floats and adheres to the tip side of the casing. Can be effectively prevented, and the painting quality and work efficiency of painting work can be improved.

[Brief description of drawings]

FIG. 1 is an external view showing an electrostatic coating apparatus according to an embodiment of the present invention.

FIG. 2 is a front view seen from the direction of arrows II-II in FIG.

FIG. 3 is an external view showing an electrostatic coating apparatus according to a first modified example of the present invention.

FIG. 4 is an external view showing an electrostatic coating device according to a second modification of the present invention.

FIG. 5 is an external view showing a conventional electrostatic coating device.

FIG. 6 is a front view seen from the direction of arrows VI-VI in FIG.

[Explanation of symbols]

 2 casing 3 rotary atomizing head 9, 33, 42 object to be coated 24 external electrode 11 vertical movement reciprocator (reciprocating means) 32 gate type reciprocator (reciprocating means) 41 robot (reciprocating means)

Claims (1)

[Claims] 1. A cylindrical casing, a rotary atomizing head that is rotatably provided at a tip end side of the casing and atomizes paint supplied through the casing, and a diameter that is larger than that of the rotary atomizing head. A plurality of external electrodes that are located on the outer side in the direction and are spaced apart in the circumferential direction on the base end side of the casing, and that electrify the paint atomized by the rotary atomizing head; and the casing with respect to the object to be coated. And a reciprocating means for coating the object by reciprocating in a predetermined direction. In the electrostatic coating apparatus, each of the external electrodes is provided in a forward direction and a backward direction of the casing by the reciprocating means. The electrostatic coating device is characterized in that the external electrodes are arranged one by one, and the remaining external electrodes are located between the pair of external electrodes in the reciprocating direction and are spaced apart by a predetermined angle in the circumferential direction.