JP2001252596A - Electrostatic coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elecrostatic coating device, in which time for continuous use can be prolonged by reducing dirt caused by mists of coating. SOLUTION: A first air ring 30 is arranged so as to surround the periphery of a rotary atomization head on the rear side of the rotary atomization head 14 in the electrostatic coating device 10A. A second air ring 40 is arranged so as to surround the periphery of the first air ring and an air jetting port 51 for jetting shaping air between the first and second air rings is formed. The rotary atomization head and the first and second air rings are formed of an electric insulating material. A discharge electrode 16A is arranged in an air flow region caused in accordance with jetting of shaping air and also the tip of the discharge electrode is positioned on the outside of the first air ring and on the rear side from the tip side of the first air ring.

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, and more particularly, to a rotary atomization method using a so-called external electrode system suitable for a coating material having an extremely low electric resistance represented by a water-based coating material. The present invention relates to a head type electrostatic coating device.

[0002]

2. Description of the Related Art An electrostatic coating apparatus having a rotary atomizing head, also called a bell cup, is known. The rotary atomizing head type electrostatic coating device sprays paint by atomizing and spraying the paint by rotating the rotary atomizing head at high speed, and also applies a high voltage to the object to be coated and forms it with the object to be coated. The charged paint particles fly along the applied electrostatic field and are applied to the object to be coated.

[0003] In the case of low-resistance paints such as water-based paints and metallic paints, the electrical conductivity of the paint liquid is extremely higher than that of solvent-based paints. High voltage cannot be applied directly. For this reason, a rotary atomizing head type electrostatic coating device using an external electrode system in which a discharge electrode to which a high voltage is applied from the outside is arranged around the coating machine body and the discharge electrode is separated from the tip of the coating machine. It has become mainstream (for example, see Japanese Unexamined Patent Application Publication No. 8-332
No. 418).

A conventional rotary atomizing head type electrostatic coating apparatus using an external electrode system comprises a coating machine main body, a metal rotary atomizing head disposed on the tip side of the coating machine main body, and a back surface of the rotary atomizing head. It has a shaping air ring provided so as to cover the side, and a discharge electrode which is arranged at a position radially outward of the coating machine main body and charges paint particles sprayed from the rotary atomizing head. An air ejection port is formed in the shaping air ring, and shaping air is ejected from the air ejection port.

[0005]

In the external electrode type electrostatic coating apparatus, there is a problem that the coating machine body and the shaping air ring are easily stained by the mist of the coating. As a result, the time during which the coating apparatus can be used continuously becomes short, and the coating operation must often be interrupted in order to clean the main body of the coating machine. Therefore, the problem of easy soiling substantially causes an increase in the cost of the painting operation. Moreover, if the cleaning cycle is incorrectly set to be longer, mist stains adhering to the main body of the coating machine or the like may fall on the object to be coated.
There is a possibility that the painting operation needs to be repeated.

As described above, dirt on the coating machine body or the like is not preferable. However, the dirt is caused by arranging a member having a complicated shape such as a discharge electrode around the shaping air ring. This is also an essential disadvantage of the conventional external electrode type electrostatic coating apparatus.

The inventor of the present invention has conducted intensive studies in order to solve the problems associated with the above-mentioned prior art. As a result, the discharge electrodes are arranged in an air flow region generated by the ejection of shaping air, and the rotary atomizing head is electrically insulated. It has been found that by providing a partition wall formed of a material and an electrically insulating material between the air motor and the air motor, contamination by paint mist is significantly reduced, and the present invention has been completed.

Accordingly, an object of the present invention is to provide an electrostatic coating apparatus capable of reducing the stain caused by paint mist and extending the continuous use time.

[0009]

According to the first aspect of the present invention, there is provided a rotary shaft rotated by an air motor, and a sprayer provided at a tip end of the rotary shaft and spraying paint from a front side. A rotary atomizing head, and a discharge electrode to which a high voltage is externally applied to charge paint particles sprayed from the rotary atomizing head, A first partition wall disposed so as to surround the periphery of the rotary atomizing head, a second partition wall disposed so as to surround the periphery of the first partition wall, and the first partition wall. An air ejection port formed between the second partition and the second partition, and configured to eject shaping air, wherein the rotary atomizing head, the first partition, and the second partition are formed of an electrically insulating material. Formed and generated with the ejection of the shaping air Wherein the discharge electrode is arranged in the arc flow region, and the tip of the discharge electrode is located outside the first partition and behind the tip of the first partition. Device.

[0010] The invention according to claim 2 is characterized in that the air flow region is either a region where the ejected shaping air flows directly or a region where the air induced by the ejected shaping air flows. The electrostatic coating apparatus according to claim 1, wherein

According to a third aspect of the present invention, the discharge electrode is formed of a thin film formed by applying a conductive paint or a metal material. Device.

According to a fourth aspect of the present invention, there is provided the electrostatic coating apparatus according to the first aspect, wherein a tip of the discharge electrode has a wave-like tip shape.

According to a fifth aspect of the present invention, the tip of the discharge electrode is located on the front side of the tip of the second partition, and the distance from the tip of the second partition to the tip of the discharge electrode is smaller. 2. The size of the gap between the first partition and the tip of the second partition is within 12 times the gap between the first partition and the tip of the second partition.
It is an electrostatic coating apparatus described in 1.

According to a sixth aspect of the present invention, there is provided the electrostatic coating apparatus according to the first aspect, wherein the air motor is formed of a metal material and held at a ground potential.

According to a seventh aspect of the present invention, at least one of the outer peripheral portion of the air motor and the rotating shaft is formed of an electrically insulating material. It is an electrocoating device.

[0016]

The present invention configured as described above has the following effects.

According to the first or second aspect of the present invention, the discharge electrode is not disposed around the outer periphery of the first and second partition walls, but the air flow region generated by the ejection of the shaping air. , The rear side of the rotary atomizing head can be finished in a substantially streamlined shape, dirt due to paint mist can be reduced, and the continuous use time of the electrostatic coating device can be extended. Furthermore, since the rotary atomizing head and the first and second partition walls are formed of an electrically insulating material, air ions generated by corona discharge at the tip of the discharge electrode may flow to the rotary atomizing head and the air motor. Is suppressed. In addition, the generated ions are carried away sequentially by the air flow generated by the ejection of the shaping air,
The generation of new ions is promoted, and the discharge current amount increases. As a result, the coating efficiency of the paint can be increased by effectively utilizing the generated ions, and stable electrostatic coating can be performed over a long period of time.

According to the third aspect of the present invention, since the discharge electrode is formed of the conductive coating film, a stable corona discharge can be obtained, and the generation of a spark due to the abnormal approach of the object to be coated can be suppressed. Can be.

According to the fourth aspect of the present invention, since the tip of the discharge electrode is formed in a waveform, the potential gradient at the tip becomes steep, and the corona discharge current amount can be further increased.

According to the fifth aspect of the present invention, the distance from the tip of the second partition to the tip of the discharge electrode is within 12 times the gap between the first partition and the tip of the second partition. Since the dimensions are set, it is possible to obtain an air flow velocity sufficient to carry away ions generated in the vicinity of the discharge electrode, and maintain the effect of increasing the discharge current amount.

According to the sixth aspect of the present invention, the first and second electrically insulating partition walls are interposed between the discharge electrode and the air motor made of a metal material. The flow is suppressed, and the generated ions can be effectively used to increase the coating efficiency of the paint.

According to the seventh aspect of the invention, the generated ions are suppressed from flowing to the air motor, and the generated ions can be effectively used to increase the coating efficiency of the paint.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a cross-sectional view showing a structure of a tip portion of an electrostatic coating apparatus according to Embodiment 1 of the present invention.
FIG. 2 is an external view of a tip portion of the electrostatic coating device according to the first embodiment.

As shown in FIG. 1, the electrostatic coating apparatus 10A
A hollow shaft 12 serving as a rotating shaft rotated by an air motor 11, a shaping air ring 13 through which the hollow shaft 12 is inserted, and a front end of the hollow shaft 12 which is screwed to the tip of the hollow shaft 12 protruding from the shaping air ring 13. Atomizing head 14 spraying paint from
A feed tube 15 disposed in a central hole of the hollow shaft 12; and a discharge electrode 1 to which a high voltage is externally applied to charge paint particles sprayed from the rotary atomizing head 14.
6A.

The outer periphery of the air motor 11 is formed of a metal material, and the outer periphery of the air motor 11 is covered by a housing 17 formed of an electrically insulating material. Further, the air motor 11 is grounded to the ground via the cable 18 and is kept at the ground potential.

The hollow shaft 12 is formed from an electrically insulating material. The hollow shaft 12 is rotatably supported in the air motor 11 via an air bearing (not shown), and is rotationally driven by a driving unit (not shown).

The feed tube 15 is a conduit for supplying the paint, and its tip extends toward the inside of the rotary atomizing head 14. A paint valve is provided on the base end side of the feed tube 15, and the paint valve communicates with a paint tank (neither is shown) through a paint pipe.

The rotary atomizing head 14 has a substantially cup shape,
A cup-shaped outer peripheral surface 20, an inner peripheral paint smooth surface 21,
And a paint discharge edge 22 on the tip side. The rotary atomizing head 14 is formed from an electrically insulating material. A paint inflow chamber 24 is defined inside the rotary atomization head 14 by a dividing wall 23, and the paint inflow chamber 24 communicates with a tip opening of a feed tube 15. The divided wall 23 is formed with a central opening 25 located at a central portion and a number of paint outlet holes 26 located at a peripheral portion. A large number of paint outlet holes 26 are circumferentially arranged at predetermined intervals.

The shaping air ring 13 is located at the tip of the air motor 11 and is screwed to the tip of the housing 17. The shaping air ring 13 in the illustrated example is located on the rear side of the rotary atomizing head 14 and is disposed so as to surround the outer peripheral surface 20 of the rotary atomizing head 14 (first partition 30). And a second air ring 30 arranged to surround the first air ring 30.
An air ring 40 (corresponding to a second partition) is provided. Both the first air ring 30 and the second air ring 40 are formed from an electrically insulating material.

The first air ring 30 includes the hollow shaft 1
2 and a central hole 31 through which the rotary atomizing head 14 is inserted, a large-diameter portion 34 in which screw portions 32 and 33 are formed on the outer peripheral surface, and a flange 35 projecting radially outward from the large-diameter portion 34.
And a small-diameter portion 36 that extends from the large-diameter portion 34 with a reduced diameter so as to surround the outer peripheral surface 20 of the rotary atomizing head 14. A smooth radius surface 37 is formed from the large diameter portion 34 to the small diameter portion 36.

The second air ring 40 has a threaded portion 41 formed on the inner peripheral surface of a threaded portion 41 fixed to the threaded portion 32 of the first air ring 30. And a tongue portion 43 that performs the operation. Tongue 43
Extend so as to form a space 50 between the first air ring 30. The tip of the tongue 43 is smoothly curved toward the front. Thereby, an annular gap is formed between the outer peripheral surface of the first air ring 30 and the tip of the second air ring 40, and the shaping air is indicated by arrow A.
An air ejection port 51 ejecting in the direction is formed.

The shaping air ring 13 is formed by connecting the ring portion 42 of the second air ring 40 to the first air ring 30.
Is formed by fastening to the screw portion 32 of The second air ring 40 is screwed in until the rear end of the ring portion 42 contacts the front surface of the flange 35. The shaping air ring 13 is attached to the housing 17 by fastening the large-diameter portion 34 of the first air ring 30 to a screw portion 52 formed on the inner peripheral surface at the distal end of the housing 17. The shaping air ring 13 is screwed in until the flange 35 comes into contact with the tip of the housing 17. Shaping air ring 13 to housing 1
7, the first air ring 30 is fixed in a state where the rear end of the small diameter portion 36 is in contact with the front surface of the air motor 11.

The large diameter portion 34 of the first air ring 30 includes
Air inlet 3 communicating with air supply pump (not shown)
8 are formed through. In the space 50 formed between the first air ring 30 and the second air ring 40,
Shaping air is introduced through the air introduction hole 38 and an air pipe (not shown), and the introduced shaping air is ejected through the air ejection port 51.

The discharge electrode 16A is connected to the first air ring 30
Of the discharge electrode 16A is provided from the round surface 37 to the small diameter portion 36 of the outer surface of the first air ring 30.
It extends to a position behind the tip of the. That is, the discharge electrode 16A is disposed in an air flow region generated by the ejection of the shaping air, and
The tip of A is outside the first air ring 30 and
The air ring 30 is disposed so as to be located rearward of the front end.

Here, the air flow region generated by the ejection of the shaping air is a concept including both an area in which the ejected shaping air flows directly and an area in which the air induced by the ejected shaping air flows. However, in the first embodiment, the discharge electrode 16A is disposed in a region where the jetted shaping air flows directly.

The first air ring 30 has the discharge electrode 16
A metal plate 53 electrically connected to A is insert-molded. The metal plate 53 is exposed to the outside on the back side of the flange 35, and is further electrically connected to an external high voltage generator 55 via a metal plate 54 inserted into the housing 17 or a cable (not shown). ing. A predetermined applied voltage is applied to the discharge electrode 16A via the metal plates 53 and 54 and a cable in order to generate a corona discharge between the discharge electrode 16A and the object to be coated.

The discharge electrode 16A of the first embodiment is composed of a thin film formed by applying a conductive paint to the surface of the base material of the first air ring 30 formed of an electrically insulating material. When the discharge electrode 16A is formed from a conductive coating film, an electrode having a predetermined shape can be formed at a low cost and with easy workability.

The tip of the discharge electrode 16A is located on the front side of the tip of the second air ring 40. Further, as shown in FIG. 2, the tip of the discharge electrode 16A has a wave-like tip shape. If the discharge electrode 16A is tapered toward the tip, the electric field concentration at the tip tends to occur more stably. In order to form a uniform discharge electric field centered on the rotation axis of the rotary atomizing head 14, the distal ends of the discharge electrodes 16A are provided at equal intervals along the circumferential direction.

The electrically insulating material which is the base material of the rotary atomizing head 14 is not particularly limited as long as it has sufficient resistance to the coating composition used, especially a solvent and the like, and is insulative. It is not something to be done. Although it depends on the type of the coating composition used, for example, polycarbonate; polyamide such as nylon; polyolefin such as polypropylene and polyethylene; polystyrene;
Polyethylene terephthalate; Polybutylene terephthalate; Hard vinyl chloride resin; Poly (meth) acrylic resin; Polyacetal; Modified polyphenylene oxide; Polyphenylene sulfide; Polysulfone; Polyether sulfone; Polyimide;
Ketone polymers such as polyetheretherketone;
Fluoropolymers such as polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, and polyvinylidene fluoride; epoxy resins; unsaturated polyester resins; phenolic resins; various synthetic resins such as melamine resins; Reinforcements with insulating fillers such as fibers, and polymer alloys and laminates thereof.) Alternatively, it may be made of ceramics such as alumina, beryllia, zircon, mullite, steatite, forsterite, silicon oxide, silicon nitride, and boron nitride; and insulating inorganic materials such as quartz glass. Of course, it is also possible to form a composite or a laminate of these synthetic resins and inorganic materials, and furthermore, as long as the electrical insulation on the outer surface side is sufficiently maintained, metal or metal inside for the purpose of reinforcement, etc. It is also possible to use a conductive material such as carbon. Among these electrically insulating materials, for example, PEEK (polyetheretherketone) is a particularly preferable material in consideration of durability, mechanical strength, economy, and the like.

The first and second air rings 30, 40
Considering the ease of processing and sufficient electrical insulation, the electrically insulating material which is the base material of PEM (polyacetal), PF,
A (perfluoroalkoxy fluororesin) is a particularly preferred material. The same thing is used for the electrically insulating material which is the base material of the housing 17.

As the conductive filler in the conductive coating composition constituting the discharge electrode 16A, silver particles, carbon black, or the like is used. As a resin component, that is, a binder, of the conductive coating film, an organic coating film having a baking temperature of 200 ° C. or less, such as an epoxy resin or a phenol resin, can be used. The baking temperature may be lower than the heat-resistant temperature of the base material. For example, in the case of the rotary atomizing head 14 using PEEK resin as the base material, it can be used without any problem if the temperature is 240 ° C. or lower.

When the discharge electrode 16A is formed by applying a conductive paint, a thin film having a thickness of about several tens of μm can be obtained, and the weight of the discharge electrode 16A can be reduced. Furthermore, since the conductive paint imparts conductivity by dispersing a conductive filler or a semiconductive filler in a resin serving as a binder, by selecting the type and amount of the filler to be dispersed, the There is also an advantage that the resistance value can be adjusted relatively easily. Note that the term “semi-conductive” refers to a material that has conductivity but does not have an electrical resistance that is as high as an electrical insulation, but is slightly larger.

Next, the operation will be described.

The hollow shaft 1 is driven by the air motor 11.
2 and the rotary atomizing head 14 are rotated at high speed. The paint is guided to the paint inflow chamber 24 through the feed tube 15, and is supplied to the front surface of the rotary atomizing head 14 from the central opening 25 and the paint outlet hole 26. The supplied paint is thinly stretched along the paint smooth surface 21 by centrifugal force due to the rotation of the rotary atomizing head 14, and is atomized and atomized from the paint discharge edge 22 and discharged.

The released paint particles try to fly radially outward due to centrifugal force. However, air spout 5
The discharged paint particles are controlled or shaped into a desired pattern so as to be squeezed forward by the shaping air ejected from 1 in the direction of arrow A, and are carried toward the object to be coated. The surrounding air is also attracted and flows by the shaping air ejected in the direction of arrow A as shown by arrow B.

On the other hand, a high voltage is applied to the discharge electrode 16A from the outside, and corona discharge is performed from the electrode tip toward the object to be coated. The discharge electrode 16A has, for example, -60 to
A high voltage of -90 kV is applied, and the vicinity of the tip is a negative ionization zone. The paint particles are charged by corona discharge, and the charged paint particles fly toward the object connected to the ground, and efficiently adhere to the surface of the object by Coulomb force.

In the electrostatic coating apparatus 10 A of the first embodiment, the discharge electrodes having a complicated shape are arranged around the shaping air ring 13, particularly, around the outer side in the radial direction behind the shaping air ring 13. Instead, it is arranged in the air flow region generated by the ejection of the shaping air, so that the shape from the rotary atomizing head 14 to the housing 17 can be finished in a streamlined manner. This allows
It is possible to extremely lengthen the time until partial stains due to paint mist occur.

This effect is obtained because the discharge electrode 16A
Is located in the air flow area generated by the ejection of shaping air, but in conjunction with this, it is a form that can effectively use the ions of the air generated by corona discharge, so conventionally, It is considered that the contribution of arranging the discharge electrode 16A at a position that has been considered to be ineffective is large.

That is, in the conventional electrostatic coating apparatus having a metal rotary atomizing head, a configuration in which a discharge electrode is provided around the outer periphery of the coating machine and the discharge electrode is separated from the tip of the coating machine is mainly used. Even if such a configuration is adopted, more than half of the generated ions flow into the metal rotary atomizing head which is maintained at a substantially ground potential. The ions that have flowed into the rotary atomizing head cannot contribute to improving the coating efficiency, which is the purpose of applying a high voltage.

On the other hand, in the first embodiment, since the rotary atomizing head 14 is formed of an electrically insulating material, almost no ion flow to the rotary atomizing head 14 occurs.

Further, the air motor 11 is generally formed of a metal material.
In addition, since the second air ring 40 is formed from an electrically insulating material, an electrically insulating partition is interposed between the discharge electrode 16A and the air motor 11, and flows from the discharge electrode 16A to the air motor 11. The number of ions can be extremely reduced. Most of the air ions generated by the corona discharge near the tip of the discharge electrode 16A are carried away in the direction of the object to be coated by the shaping air flowing therearound.
The number of ions flowing to the space is further reduced.

The flow of a large amount of air through the corona discharge portion has another effect of increasing the discharge current. As a result, it is possible to obtain a practically desirable effect that the same amount of ions as in the related art can be obtained at a lower voltage. The reason for the increase in the amount of discharge current is that the ion generation region by corona discharge is limited,
This is considered to be because ions generated in the area are rapidly and sequentially carried away by the air flow generated by the ejection of the shaping air, so that generation of new ions is promoted.

Further, since the discharge electrode 16A is formed of a conductive coating film, a stable corona discharge can be obtained, and the effect of suppressing the generation of spark due to the abnormal approach of the object to be coated can be obtained.

Further, since the tip of the discharge electrode 16A is formed in a waveform, the effect of increasing the corona discharge current can be increased. This effect is caused by a steep potential gradient at the tip of the discharge electrode 16A.

The ions generated in this way come into contact with the paint particles emitted from the rotary atomizing head 14 and have a function of increasing the coating efficiency of the paint by giving a charge to the particles.

The distance L from the tip of the second air ring 40 to the tip of the discharge electrode 16A is determined by the clearance d of the air outlet 51 (the first air ring 30 and the second air ring 40).
It is preferable to set the dimension to 12 times or less the dimension (dimension along the radial direction of the gap between the tip). As described above, it is recommended that the tip position of the discharge electrode 16A be set to be within 12 times the gap dimension d of the air outlet 51 in front of the air outlet 51 because ions generated in the vicinity of the discharge electrode 16A are This is for obtaining an air flow velocity sufficient to carry away. If the dimension is longer than 12 times, the air flow moves away from the wall surface, so that the air flow velocity in the ion generation region decreases.

As described above, according to the first embodiment, the discharge electrode 16A is disposed in the area where the shaping air flows directly, and the rotary atomizing head 14 is formed from an electrically insulating material, and is maintained at a substantially ground potential. By providing the electrically insulating shaping air ring 13 between the air motor 11 and the air motor 11, contamination by paint mist is significantly reduced, and the continuous use time of the electrostatic coating apparatus 10A can be extended. In addition, the coating efficiency of the paint can be increased by effectively utilizing the ions of the air generated by the corona discharge at the tip of the discharge electrode 16A, and stable electrostatic coating can be performed over a long period of time.

Embodiment 2 FIG. 3 is a cross-sectional view showing the structure of the tip portion of an electrostatic coating apparatus according to Embodiment 2 of the present invention. The same members as those in Embodiment 1 are denoted by the same reference numerals. The description is omitted.

As in the first embodiment, the discharge electrode 16B of the second embodiment is disposed in an air flow area generated by the ejection of the shaping air,
The tip of B is outside the first air ring 30 and
The air ring 30 is disposed so as to be located rearward of the front end. However, the second embodiment is different from the first embodiment in a specific position where the discharge electrode 16B is provided.

That is, the discharge electrode 16B of the second embodiment is
From the inner surface of the tongue 43 of the second air ring 40, the tongue 43
And is provided over the outer surface of the tongue 43. A conductive member 60 made of a conductive material is provided between the tongue 43 and the first air ring 30, and a metal plate insert-molded into the discharge electrode 16B and the first air ring 30 via the conductive member 60. 53 are electrically connected. The conductive member 60 is preferably made of an elastic body such as a spring or a spring formed of a conductive material. According to such a conductive elastic body, the electrical connection between the discharge electrode 16B and the metal plate 53 becomes reliable and stable for a long time.

The point that the discharge electrode 16B is formed of a thin film obtained by applying a conductive paint to the surface of the base material of the second air ring 40, and that the tip of the discharge electrode 16B is on the front side of the tip of the second air ring 40 , The discharge electrode 16
The point that the tip of B has a waveform tip shape is the same as in the first embodiment.

According to the electrostatic coating apparatus 10B of the second embodiment, similarly to the first embodiment, the stain due to the mist of the paint is significantly reduced, and the continuous use time of the electrostatic coating apparatus 10B can be extended. The application efficiency of the paint can be increased by effectively utilizing the generated air ions, and stable electrostatic coating can be performed over a long period of time.

Embodiment 3 FIG. 4 is a cross-sectional view showing a structure of a tip portion of an electrostatic coating apparatus according to Embodiment 3 of the present invention.
FIG. 5 is an external view of the distal end portion of the electrostatic coating device according to the third embodiment. The same members as those in the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted.

As in the first and second embodiments, the discharge electrode 16C of the third embodiment is disposed in an air flow area generated by the ejection of the shaping air, and the tip of the discharge electrode 16C is connected to the first air ring 30. Outside of and
The first air ring 30 is disposed so as to be located rearward of the front end. However, the third embodiment is different from the first embodiment in that the discharge electrode 16C is arranged in a region where the air induced by the ejected shaping air flows, and the discharge electrodes 16A and 16B are arranged in a region where the ejected shaping air flows directly. , 2.

That is, the discharge electrode 16C of the third embodiment is
From the outer surface of the ring portion 42 of the second air ring 40 to the tongue portion 4
3 is provided over the outer surface. First air ring 3
A metal plate 70 is insert-molded on the zero flange 35, and the discharge electrode 16C and the metal plate 54 insert-molded in the housing 17 are electrically connected via the metal plate 70. Since the induced air flows as indicated by the arrow B due to the shaping air ejected in the direction of the arrow A, the discharge electrode 16C is disposed in a region where the induced air flows.

The point that the discharge electrode 16C is formed of a thin film obtained by applying a conductive paint to the surface of the base material of the second air ring 40, and the tip of the discharge electrode 16C has a wave-like tip shape as shown in FIG. Is the same as the first and second embodiments.

According to the electrostatic coating apparatus 10C of the third embodiment, similarly to the first and second embodiments, dirt due to paint mist can be significantly reduced, and the continuous use time of the electrostatic coating apparatus 10C can be extended. Moreover, the efficiency of the paint application can be increased by effectively utilizing the generated air ions.
It is possible to perform stable electrostatic coating over a long period of time.

In the first to third embodiments, the discharge electrodes 16A to 16A constituted by a thin film formed by applying a conductive paint are used.
Although C is illustrated, the present invention is not limited to this. Even if the discharge electrode is formed from a metal plate, there is no problem in reducing stains due to paint mist.

The generated ions are supplied to the air motor 11.
From the viewpoint of further suppressing the flow to the outside and increasing the coating efficiency of the paint by effectively utilizing the generated ions, at least one of the outer peripheral portion of the air motor 11 and the hollow shaft 12 is formed of an electrically insulating material. May be.

The present invention is not limited to water-based paints, but can be applied in principle to solvent-based paints without any problem.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of a distal end portion of an electrostatic coating device according to a first embodiment of the present invention.

FIG. 2 is an external view of a tip portion of the electrostatic coating device according to the first embodiment.

FIG. 3 is a cross-sectional view illustrating a structure of a tip portion of the electrostatic coating device according to the second embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a structure of a tip portion of an electrostatic coating device according to a third embodiment of the present invention.

FIG. 5 is an external view of a tip portion of an electrostatic coating device according to a third embodiment.

[Explanation of symbols]

10A, 10B, 10C Electrostatic coating device 11 Air motor 12 Hollow shaft (rotating shaft) 13 Shaping air ring 14 Rotary atomizing head 16A, 16B, 16C Discharge electrode 30 First air ring (first 40: second air ring (second partition) 51: air outlet arrow A, arrow B: air flow generated due to ejection of shaping air L: from the tip of the second partition to the tip of the discharge electrode Distance

Claims (7)

[Claims] 1. A rotary shaft rotated by an air motor, a rotary atomizing head provided at a tip end side of the rotary shaft and spraying paint from a front side, and paint particles sprayed from the rotary atomizing head are charged. A discharge electrode to which a high voltage is applied from the outside, wherein the first electrode is located behind the rotary atomizing head and is arranged to surround the rotary atomizing head. A second partition disposed so as to surround the periphery of the first partition; and an air jet formed between the first partition and the second partition and configured to discharge shaping air. An outlet, wherein the rotary atomizing head, the first partition and the second partition are formed of an electrically insulating material, and the discharge electrode is formed in an air flow region generated by the ejection of the shaping air. With the arrangement, the discharge electrode Electrostatic coating apparatus characterized by an end was positioned rearward from the front end of the outer a and the first partition wall of the first partition wall. 2. The air flow area according to claim 1, wherein the air flow area is an area in which the jetted shaping air flows directly or an air flow area in which the air drawn by the jetted shaping air flows. Electrostatic coating equipment. 3. The discharge electrode according to claim 1, wherein the discharge electrode comprises a thin film formed by applying a conductive paint.
An electrostatic coating device according to item 1. 4. The electrostatic coating apparatus according to claim 1, wherein a tip of the discharge electrode has a waveform tip shape. 5. A tip of the discharge electrode is located forward of a tip of the second partition, and a distance from a tip of the second partition to a tip of the discharge electrode is equal to a distance between the first partition and the first partition. 2. The electrostatic coating apparatus according to claim 1, wherein a size of the gap is equal to or less than 12 times a gap between the second partition and a tip of the second partition. 3. 6. The electrostatic coating apparatus according to claim 1, wherein the air motor is formed of a metal material and is kept at a ground potential. 7. The electrostatic coating apparatus according to claim 1, wherein at least one of an outer peripheral portion of the air motor and the rotating shaft is formed of an electrically insulating material.