JPH06226151A - Bell-shaped electrostatic coating device - Google Patents

Abstract

PURPOSE:To suppress the adhesion of the coating particles discharged from an atomizing head to the resin cover of an air motor to a large extent. CONSTITUTION:In a bell-shaped electrostatic coating device 11 wherein a plurality of external electrodes 15 negatively charging the coating particles 20 discharged from an atomizing head 14 are arranged to the outer periphery of the atomizing head 14 rotated at a high speed, the external electrodes 15 are integrated with the resin cover 16 of the air motor 13 rotating the atomizing head 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bell-type electrostatic coating device for suppressing stains on the electrostatic coating device due to adhesion of paint.

[0002]

2. Description of the Related Art Since a water-based paint has a small electric resistance value, when a high voltage is directly applied to an electrostatic coating device, electricity leaks through the paint tank. Therefore, in electrostatic coating work using a water-based paint, a plurality of external electrodes are provided on the outer periphery of the atomizing head rotated at high speed, and a negative electric charge is given to the paint particles by the electrostatic field generated by these external electrodes. ing. As prior art related to this, for example, JP-A-55-39205 and JP-A-61-78452.
The publication is known.

FIG. 4 and FIG. 5 show an example of a conventional bell type electrostatic coating device. In FIGS. 4 and 5, 1
Indicates a resin plate. An air motor 2 is attached to the resin plate 1 via a resin cover 3. Air motor 2
The atomizing head 4 is connected to the output shaft of the. A plurality of external electrodes 5 are arranged on the outer periphery of the resin cover 3. The outer periphery of each external electrode 5 is covered with resin,
The root portion of is fixed to the resin plate 1.

The air motor 2 and the atomizing head 4 are grounded. The external electrode 5 is connected to the negative side of the high voltage generator 6. The positive side of the high voltage generator 6 is grounded. At the position opposite to the atomizing head 4, the atomizing head 4
The object 7 to be coated is arranged at a predetermined interval. The object to be coated 7 is grounded similarly to the positive side of the air motor 2, the atomizing head 4 and the high voltage generator 6. The paint particles 8 are emitted from the atomizing head 4 toward the object 7 to be coated.

[0005]

However, the bell-type electrostatic coating apparatus shown in FIGS. 4 and 5 has the following problems.

As shown in FIGS. 4 and 5, the external electrode 5
And the resin cover 3 of the air motor 2 is short,
Moreover, between the external electrode 5 and the resin cover 3 is -30 to-.
Since a potential difference of 60 kv occurs, the external electrode 5
A stronger electrostatic field is formed between the target and the object 7 to be coated. Therefore, when the negatively charged paint particles 8 enter between the external electrode 5 and the resin cover 3, the paint particles 8 are attracted to the grounded resin cover 3 side by electrostatic force, as shown in FIG. Due to the adhesion of the particles 8, the electrostatic coating device is significantly soiled in a short period of time.

When the amount of paint particles attached to the electrostatic coating device increases, the deposited paint easily separates, and the separated paint pieces adhere to the object to be coated, degrading the coating quality of the object to be coated. The problem arises. In addition, if the amount of paint particles attached to the resin cover becomes too large, a problem such as high voltage abnormality may occur.

In view of the above problems, the present invention provides a bell-type electrostatic coating device capable of greatly suppressing the adhesion of paint particles discharged from the atomizing head to the resin cover of the air motor. The purpose is to

[0009]

A bell-type electrostatic coating apparatus according to the present invention for achieving the above object is provided on the outer periphery of an atomizing head rotating at a high speed with a negative effect on paint particles discharged from the atomizing head. In a bell-type electrostatic coating device in which a plurality of external electrodes for charging electric charges are arranged, the external electrodes are integrated with a resin cover of an air motor for rotating the atomizing head.

[0010]

In the bell-type electrostatic coating device constructed as described above, the coating particles discharged from the atomizing head are charged with a negative electric charge by the electrostatic field generated by the external electrodes. Here, since the resin cover for the air motor and the external electrode are integrated, there is no place where a large potential difference occurs on the outer circumference of the atomizing head, and the concentration of electrostatic field is avoided. Further, on the outer peripheral surface of the resin cover, it becomes possible to apply a repulsive force to the negatively charged paint particles by the electrostatic field from the external electrode. Thus, by avoiding the concentration of the electrostatic field and repelling the paint particles on the outer peripheral surface of the resin cover, the adhesion of the paint particles to the resin cover is significantly suppressed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a bell type electrostatic coating device according to the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the present invention. In FIGS. 1 and 2, reference numeral 11 denotes a bell-type electrostatic coating device. The bell-type electrostatic coating device 11 includes a disc-shaped resin plate 12. An air motor 13 is attached to the center of the resin plate 12. Air motor 1
An atomizing head 14 is attached to the output shaft of the No. 3. The water-based paint is supplied to the inner peripheral surface of the atomizing head 14 through a passage (not shown).

A plurality of external electrodes 15 made of metal are arranged on the outer periphery of the air motor 13. In this embodiment, six external electrodes 15 are arranged. The root portion of the external electrode 15 is fixed to the resin plate 12. Air motor 13
The outer periphery of is covered with a resin cover 16. Each external electrode 15 is embedded in a resin cover 16, and a tip portion 15 a thereof projects slightly from the tip surface of the resin cover 16. The metal external electrode 15 is integrally molded with the resin cover 16 when the resin cover 16 is molded.

The vicinity of the resin cover 16 where the tip portion 15a of the external electrode 15 is located is formed as a conical portion 16a which tapers toward the tip. In this embodiment, the resin cover 16 has a substantially L-shaped cross section for weight reduction. As a result, most of the inside of the external electrode 15 is the hollow portion 17, but the hollow portion 17 may be entirely resinized.

It is desirable that the radius of the conical portion 16a of the resin cover 16 where the tip portion 15a of the external electrode 15 is located is twice the radius of the atomizing head 14 or less so that the charging rate is high. Further, in the present embodiment, the number of the external electrodes 15 is 6, but the atomizing head 14
It is desirable to provide about 4 to 10 rotation centers with the rotation center of (1) as axial symmetry. The air motor 13 is grounded. The external electrode 15 is connected to the negative side of the high voltage generator 18. The positive side of the high voltage generator 18 is grounded.

At the position facing the atomizing head 14, the atomizing head 1
4 and the object 19 to be coated are arranged at a predetermined interval. The object to be coated 19 is grounded. From the atomizing head 14, paint particles 20 of a water-based paint are discharged toward the object to be coated 19. A high voltage of −30 to −60 kv is applied to each external electrode 15 by a high voltage generator 18. The paint particles 20 discharged from the atomizing head 14 are negatively charged by the external electrode 15.

Next, the operation of the bell-type electrostatic coating device will be described. When the object to be coated 19 is positioned at a predetermined position, the water paint (not shown) is supplied toward the atomizing head 14 that rotates at a high speed by the air motor 13. When the water-based paint is supplied to the atomizing head 14, the water-based paint separates from the atomizing head 14 by the high speed rotation of the atomizing head 14,
The paint particles 20 are released into the air.

A plurality of external electrodes 15 are provided on the outer circumference of the atomizing head 14.
Are disposed, the paint particles 20 emitted from the atomizing head 14 are negatively charged by the ions (electrons) from the external electrode 15, and the negatively charged paint particles 20 are charged to the external electrode 15 and the object to be coated 19. To be coated 1 by the electrostatic field between
9 will be attached. Therefore, most of the paint particles 20 discharged from the atomizing head 14 can be attached to the object to be coated 19, and the coating efficiency can be improved.

Here, of the paint particles 20 emitted from the atomizing head 14, the paint particles 20 do not adhere to the object to be coated 19 and the electrostatic coating device 1
There are paint particles 20 flying to 1. As shown in FIG. 3, since the external electrode 15 and the resin cover 16 are integrated into the negatively charged paint particles 20 flying toward the electrostatic coating device 11, the negatively charged paint particles 18 are Resin cover 16
Then, the paint particles 20 are suppressed from adhering to the resin cover 16.

[0020]

According to the present invention, since the resin cover of the air motor for rotating the atomizing head at a high speed is integrated with the external electrode, the electrostatic field is prevented from concentrating on the outer periphery of the atomizing head due to a large potential difference. At the same time, it becomes possible to electrically repel the paint particles flying toward the electrostatic coating device side, out of the paint particles emitted from the atomizing head, with the resin cover of the air motor.

Therefore, it is possible to prevent the paint particles from adhering to the electrostatic coating device side, and to prevent the coating quality from deteriorating due to the paint adhering to the electrostatic coating device coming off and adhering to the object to be coated. be able to. Further, it is possible to eliminate the occurrence of defects such as high voltage abnormality due to an increase in the amount of paint particles attached to the resin cover.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a bell-type electrostatic coating device according to an embodiment of the present invention.

FIG. 2 is a front view of FIG.

3 is a schematic diagram showing a moving state of paint particles discharged from the atomizing head of the apparatus of FIG. 1. FIG.

FIG. 4 is a schematic configuration diagram of a conventional bell-type electrostatic coating device.

FIG. 5 is a front view of FIG.

6 is a schematic diagram showing a moving state of paint particles discharged from the atomizing head of the apparatus of FIG.

[Explanation of symbols]

 11 Bell-type Electrostatic Coating Device 13 Air Motor 14 Atomizing Head 15 External Electrode 16 Resin Cover 18 High Voltage Generator 19 Painted Object 20 Paint Particles

Claims (1)

[Claims] 1. A bell-type electrostatic coating apparatus in which a plurality of external electrodes for charging coating particles discharged from the atomizing head with negative charges are arranged around the outer periphery of the atomizing head rotating at high speed. A bell-type electrostatic coating device characterized by being integrated with a resin cover of an air motor for rotating the atomizing head.