JP6044774B2 - Electrostatic coating machine - Google Patents

Description

  The present invention relates to an electrostatic coating machine, and more specifically, an internal paint path that guides paint supplied to the machine body through an external paint path to a spray part at the tip of the machine body is provided inside the machine body, and paint that is sprayed from the spray part to the outside is provided. The present invention relates to an electrostatic coating machine provided with charging means for making a charged state by a voltage generated by a high voltage generator.

  Electrostatic coating machines have a direct charging method and an indirect charging method. In the direct charging method, a conductive electrode is provided inside the machine as a charging means, and a high voltage generated by a high voltage generator is applied to this conductive electrode. In this state, the paint before spraying is directly brought into contact with the conductive electrode to charge the paint before spraying, and the charged paint is sprayed from the spraying portion (see Patent Document 1).

  On the other hand, in the indirect charging method, an external electrode is arranged in the vicinity of the spraying part outside the coating machine main body as a charging means, and a high voltage generated by a high voltage generator is applied to the external electrode so that the corona discharge region is near the spraying part. By spraying the coating material from the spraying portion in a state where is formed, the coating material immediately after spraying is charged in a non-contact state with the external electrode by corona discharge (see Patent Document 2).

JP 2006-346596 A JP-A-4-215864

  However, when the paint used is a solvent-based paint, there is no particular problem because the electrical resistance value of the solvent-based paint is high, but when using a paint with a low electrical resistance value such as a water-based paint or metallic paint, The electric charge applied to the paint due to contact with the conductive electrode in the high voltage application state leaks to the ground through the subsequent paint in the internal paint path and the external paint path, which makes electrostatic painting impossible.

  For this reason, when using paints with low electrical resistance such as water-based paints and metallic paints by the direct charging method, the paint that is charged by contact with the conductive electrode and sent to the spray section and the subsequent paints are continuous. Therefore, there is a problem in that an insulating means for electrically insulating is required, and the structure of the coating machine and the surroundings of the coating machine becomes complicated, which increases the cost of the apparatus and increases the burden of apparatus maintenance.

  In addition, since the continuity of the paint is cut off, continuous coating over a long period of time cannot be performed, which causes a problem that the workability of the coating is restricted.

  On the other hand, in the indirect charging method, the paint after spraying is charged, so the charge applied to the paint does not leak to the ground through the subsequent paint, but the paint is indirectly in contact with the external electrode by corona discharge. Therefore, the charging voltage of the paint is lower than that of the direct charging method, and therefore, there is a problem that the coating efficiency with respect to the object to be coated is limited as compared with the direct charging method.

In addition, since the external electrode is disposed in the vicinity of the spraying portion outside the machine body, the spray paint is often attached to the external electrode, which causes a problem of increasing the burden of cleaning maintenance for removing the attached paint.

  In view of this situation, the main problem of the present invention is to effectively solve the above problems by adopting a rational charging method.

The first characteristic configuration of the present invention relates to an electrostatic coating machine,
An internal paint path is installed inside the fuselage to guide the paint supplied to the fuselage through the external paint path to the spray section at the tip of the fuselage.
An electrostatic coating machine provided with charging means for charging the paint sprayed to the outside from the spraying portion with a voltage generated by a high voltage generator,
As the charging means, an induction electrode portion for applying a voltage generated by the high voltage generator is placed in the vicinity of the internal paint path inside the fuselage in a state where it is not in electrical contact with the paint passing through the internal paint path. Place and
By charging the induction electrode part with a voltage applied by the high voltage generator, the paint passing through the internal paint path is charged to a polarity opposite to the polarity of the applied voltage to the induction electrode part by electrostatic induction. , The charging paint is sprayed from the spraying part,
As the spraying section, a rotary atomizing head that disperses the paint supplied from the internal paint path from the outer peripheral edge by centrifugal force accompanying rotation,
A rotary output shaft of an air motor provided inside the machine body is connected to the rotary atomizing head, and the rotary atomizing head is rotated by the air motor,
A paint supply tube forming the internal paint path is inserted through a central hole in the rotation output shaft of the air motor and passed to the rotary atomizing head;
The paint supply tube and the rotation output shaft of the air motor are formed of an electrical insulating material,
The turbine section of the air motor surrounds the rotation output shaft and the paint supply tube inside the entire circumference of the rotary output shaft and the paint supply tube in a state of being in non-contact with the passing paint of the internal paint path inside the airframe. Placed in a state,
The voltage output terminal of the high voltage generator is electrically connected to the turbine unit, whereby the turbine unit is used as the induction electrode unit .

  In the electrostatic coating machine having this configuration, electrostatic polarization is caused in the paint passing through the internal paint path by electrostatic induction by the induction electrode unit, and the subsequent charge is applied to the polarization charge having the same polarity as the voltage applied to the induction electrode unit. In addition, the passing paint is charged in such a manner that the polarization charge having the opposite polarity to the polarity of the voltage applied to the induction electrode part is retained in the passing paint while leaking to the ground part through the contact conductive part. Even when a paint having a low electric resistance value is used, the charged charge (polarized charge having the reverse polarity) applied to the paint does not leak to the ground portion through the subsequent paint.

  Therefore, even when using paints with low electrical resistance, such as water-based paints and metallic paints, charging paints can be used while eliminating the need for insulating means that break the continuity of paints that have been added to conventional direct-charging coating machines. It can be sprayed from the spraying part and electrostatic coating can be performed on the object to be coated, which makes the structure of the coating machine and the coating machine simpler than the direct charging type coating machine equipped with insulating means. Equipment costs and equipment maintenance burdens can be effectively reduced.

  In addition, since there is no need to break the continuity of the paint, even when using paints with low electrical resistance, such as water-based paints and metallic paints, continuous painting over a long period of time is possible, thereby improving the workability of painting. be able to.

  In addition, while the dielectric electrode part is for charging the paint indirectly in an electrically non-contact state, the charge is charged by electrostatic induction from the induction electrode part arranged in the vicinity of the internal paint path. As a result, the charging voltage of the paint can be increased to the same level as the voltage applied to the induction electrode, and this also improves the coating efficiency for the object to be coated compared to the indirect charging type coating machine with external electrodes. Can be enhanced.

  In addition, since the induction electrode part is arranged inside the machine body, there is no adhesion of spray paint to the induction electrode part, and this also imposes a burden on cleaning maintenance that removes the adhesion paint compared to an indirect charging type coating machine equipped with external electrodes. It can be effectively reduced.

And, in the above first feature configuration,
As the spraying section, a rotary atomizing head that disperses the paint supplied from the internal paint path from the outer peripheral edge by centrifugal force accompanying rotation,
A rotary output shaft of an air motor provided inside the airframe is connected to the rotary atomizing head, and the rotary atomizing head is rotated by the air motor,
A paint supply tube forming the internal paint path is inserted through a central hole in the rotation output shaft of the air motor and passed to the rotary atomizing head;
The paint supply tube and the rotation output shaft of the air motor are formed of an electrical insulating material ,
The turbine section of the air motor surrounds the rotation output shaft and the paint supply tube inside the entire circumference of the rotary output shaft and the paint supply tube in a state of being in non-contact with the passing paint of the internal paint path inside the airframe. Placed in a state,
Since the turbine part is made the induction electrode part by electrically connecting the voltage output terminal of the high voltage generator to the turbine part, the following effects are also achieved.

In other words, in the electrostatic coating machine having this configuration, the metal paint supply tube and the metal air motor rotation output shaft used in the direct charging type electrostatic coating machine having the rotary atomizing head are electrically insulated. The above-described electrostatic coating machine that charges the paint passing through the internal paint path by electrostatic induction can be easily manufactured with only a very simple specification change.

That is, in a direct charging type electrostatic coating machine having a rotary atomizing head, generally, the rotary atomizing head, the rotation output shaft of an air motor connected to the rotary atomizing head, and the paint supply tube to be passed to the rotary atomizing head, respectively. Is made of a metal material, and the voltage output terminal of the high voltage generator is electrically connected to the turbine section of the same metal air motor, so that the metal rotary atomizing head and the paint supply tube can be connected to a high voltage. As the applied conductive electrode, a configuration is adopted in which the paint before spraying is charged by contact of the paint with the rotary atomizing head and the paint supply tube.

Therefore, as a specification change for the electrostatic charging machine of the direct charging method, at least a metal-made air motor rotating output shaft that connects the air motor and the rotating atomizing head, and the rotating fog that is inserted through the air motor rotating output shaft. By changing the metal paint supply tube that is passed to the control head to one made of electrical insulating material, there is no conductive electrode in the direct charging method, and instead, the voltage output terminal of the high voltage generator is electrically The turbine part of the air motor connected to the inside shall be a dielectric electrode part located in the vicinity of the internal paint path (paint supply tube) in an electrically non-contact state with the paint passing through the internal paint path inside the fuselage It can be, thereby, be able to charge the passing paint by electrostatic induction by the turbine section of the air motor of the high-voltage applied state, water-based paint or methallyl Even electrostatic coating machine described above can be easily manufactured which are suitable for use electric resistance value smaller paint such as click paints also be inexpensive to its manufacturing cost.

The second characteristic configuration of the present invention specifies an embodiment suitable for the implementation of the electrostatic coating machine of the first characteristic configuration,
The rotary atomizing head is configured to have an electrical insulation property against the charged paint supplied from the paint supply tube.

  In the electrostatic coating machine having this configuration, even if the paint charged by electrostatic induction is supplied to the rotary atomizing head through the paint supply tube and comes into contact with the rotary atomizing head, the rotational atomization of the charged paint is performed. The charged paint can be atomized by the rotation of the rotary atomizing head while the charged charge of the charged paint is securely held by the electrical insulation of the head, thereby further increasing the coating efficiency on the object to be coated. Can be effectively increased.

  In addition, the electric conduction from the charged paint that contacts the rotary atomizing head may cause a spark between the rotary atomizing head and another object or worker in the ground state. It can also be prevented by insulation, which can improve the safety against a spark accident as compared with a direct charging type or indirect charging type coating machine.

  In order to make the rotary atomizing head electrically insulating with respect to the charged paint in the electrostatic coating machine of this configuration, the entire rotary atomizing head is made of an electrical insulating material, An electrical insulating coating layer may be provided on the conversion head.

The third characteristic configuration of the present invention specifies an embodiment suitable for the implementation of the electrostatic coating machine of the first or second characteristic configuration,
An air nozzle forming cover is provided that forms an outline of the front end of the airframe that is the housing portion of the air motor and forms a shaving air ejection portion between the outer periphery of the rotary atomizing head exposed to the outside through the front end opening,
This air nozzle forming cover is formed of an electrically insulating material.

According to the electrostatic coating machine of this configuration, dielectric polarization occurs also in the outer periphery of the airframe tip portion that is the housing portion of the air motor due to electrostatic induction by the turbine portion of the air motor that is charged as a high voltage application as the induction electrode portion, As a result, it is possible to prevent the occurrence of a spark between the outer shell of the airframe tip and other objects or workers in the ground state by the air nozzle forming cover made of an electrical insulating material, thereby preventing a spark accident. Safety can be further enhanced.

Longitudinal sectional view of the electrostatic charging machine of the induction charging system according to the present invention

  Fig. 1 shows an electrostatic charging machine with an induction charging system installed at the tip of the arm of a painting robot. At the tip of a shell-shaped body 1 (the main body of the coating machine), a bell-shaped rotary atomizer as a spraying part is shown. Head 2 is equipped.

  In this rotary atomizing head 2, a high voltage charged paint T (in this example, a paint having a small electrical resistance value such as a water-based paint or a metallic paint) is applied from the paint supply hole 2 a formed at the center thereof. By discharging to the inner surface side of the rotary atomizing head 2, the discharged paint T is scattered in the radial direction of the rotary atomizing head 2 in a state where it is made finer from the outer peripheral edge of the rotary atomizing head 2 by the centrifugal force generated by the rotation of the rotary atomizing head 2. The spray paint T (specifically, a dispersion group of paint particles) is redirected by the shaping air A ejected from the rear of the peripheral edge of the rotary atomizing head 2, whereby the spray pattern P of the spray paint T is sprayed. Is formed into a cylindrical shape or an inverted conical shape facing the front of the body 1.

Then, in the state of the spray pattern P, the spray paint T is applied by electrical attraction to an object (not shown) such as an automobile body to which a voltage having a polarity opposite to the charged polarity is applied. The object to be coated is applied by a so-called electrostatic coating method.

  An air nozzle forming cover 3 that forms an outline of the front end of the airframe and exposes the rotary atomizing head 2 forward from the airframe 1 through the front end opening 3a is attached to the front end of the airframe 1. By attaching the forming cover 3, a shaping air ejection part 4 is formed over the entire circumference of the front end opening 3 a in the gap between the front opening edge of the air nozzle forming cover 3 and the back surface of the rotary atomizing head 2. The shaping air A is ejected from the portion 4 toward the front of the body 1.

  More specifically, the nozzle forming cylinder 5 in which a large number of concave grooves are formed on the outer peripheral surface is fitted into the air nozzle forming cover 3 so that each concave groove of the nozzle forming cylinder 5 is covered with the air nozzle forming cover 3. Thus, each of the concave grooves is used as an air passage, and the opening on the leading end side of each concave groove is formed as an air outlet arranged along the entire circumference of the tip opening 3a in the air nozzle forming cover 3, and the annular group of these air outlets is used. The shaping air ejection part 4 is formed.

A turbine part 6a of a turbine type air motor 6 for rotating the rotary atomizing head 2 is built in the front end of the machine body 1 to which the air nozzle forming cover 3 is attached, and the turbine part 6a is supplied from the outside of the machine body 1 through a hose. By rotating with the compressed air, the rotary output shaft 6b of the air motor 6 connected to the rotary atomizing head 2 is driven to rotate, and the rotary atomizing head 2 is rotated.

  Inside the machine body 1, there is provided an internal paint path 8 that guides the paint T supplied to the machine body 1 through the external paint path 7 to the paint supply hole 2 a of the rotary atomizing head 2. The part after the paint injection nozzle 9 interposed in the internal paint path 8 is inserted by a paint supply tube 10 which is inserted into the central hole of the rotation output shaft 6b of the air motor 6 which is a hollow shaft and passed to the rotary atomizing head 2. It is formed.

  In addition, a high voltage generator 11 that generates a high voltage for charging the paint is built in the machine body 1, and a voltage output terminal 11 a of the high voltage generator 11 is connected to the turbine section 6 a of the air motor 6. It is electrically connected.

  The structure up to this point is almost the same as that of a conventional direct charging type electrostatic coating machine. In general, the direct charging type electrostatic coating machine generally has an air motor 6 for electrically connecting the voltage output terminal 11a of the high voltage generator 11. The turbine part 6a, the rotary output shaft 6b of the air motor 6 mechanically connected to the turbine part 6a, the rotary atomizing head 2 connecting the rotary output shaft 6b, and the rotary atomizing head 2 Each of the paint supply tubes 10 is made of metal, and the high voltage generator 11 applies a high voltage to the turbine section 6a, so that the rotation output shaft 6b, the rotary atomizing head 2, and the paint supply tube 10 made of metal are also high. A voltage is applied so that the rotary atomizing head 2 made of metal and the paint supply tube 10 are used as conductive electrodes for charging the paint, and the rotary atomizing head 2 and the paint supply tube are charged. And so as to charge the paint T prior to spray by contact with paint T for 0.

  On the other hand, in the electrostatic charging machine of the inductive charging type of this example, the rotation output shaft 6 b of the air motor 6, the rotary atomizing head 2, and the paint supply tube 10 are changed as specifications of the above-described direct charging type electrostatic coating machine. Each of these is formed of an electrically insulating resin material.

That is, by forming each of the rotation output shaft 6b, the rotary atomizing head 2 and the paint supply tube 10 of the air motor 6 from an electrically insulating resin material, the conductive electrode in the direct charging method is eliminated, and instead. The turbine section 6a of the air motor 6 to which the voltage output terminal 11a of the high voltage generator 11 is electrically connected is electrically in contact with the passing paint T of the internal paint path 8 inside the machine body 1. As shown in FIG. 1, the rotary output shaft 6b and the paint supply tube 10 inside the rotary output shaft 6b are made to function as a dielectric electrode portion X for charging the paint that surrounds the entire circumference in a close state.

Then, the turbine portion 6a as the dielectric electrode portion X is charged to a high voltage state by applying a high voltage by the high voltage generator 11, so that the paint T passing through the portion of the paint supply tube 10 in the internal paint path 8 can be applied. In the passing process, the high-voltage charged state of the turbine unit 6a is electrostatically induced to efficiently charge the opposite polarity to the polarity of the voltage applied to the turbine 6a , and the charged paint T is applied to the object to be coated in the rotary atomizing head 2. In contrast, it is sprayed.

  On the other hand, the air nozzle forming cover 3 that forms the outline of the front end portion of the airframe incorporating the turbine portion 6a is formed of an electrically insulating resin material together with the rotary atomizing head 2, so that the rotary atomizing head 2 and The air nozzle forming cover 3 is prevented from being in a state of being charged with a high voltage due to contact with the charged paint T or electrostatic induction by the turbine section 6a, and the rotary atomizing head 2 and the air nozzle forming cover 3 and other objects or workers. Prevent sparks from occurring between

[Another embodiment]
Next, other embodiments of the present invention will be listed.

In the above-described embodiment, an example in which the turbine portion 6a of the air motor 6 is the induction electrode portion X has been described.

In the above-described embodiment, the example in which the rotary atomizing head 2 is used as the spray unit has been described.

  In the above-described embodiment, the example in which the high voltage generator 11 is built in the airframe 1 has been described, but the high voltage generator 11 may be disposed outside the airframe 1.

  Further, in the implementation of the present invention, the polarization charge having the same polarity as the applied voltage of the induction electrode part X out of the polarization charge generated in the paint T by electrostatic induction by the induction electrode part X is guided to the ground part and removed from the paint T. An earth electrode may be additionally provided.

  The electrostatic coating machine according to the present invention is particularly suitable when using a paint having a low electrical resistance value such as a water-based paint or a metallic paint, but the paint T used is not limited to a paint having a low electrical resistance value. It may be a paint having a high electric resistance value such as a solvent-based paint.

  If the electrostatic coating machine according to the present invention, even when using a paint having a low electrical resistance value such as a water-based paint or a metallic paint, an insulating means for cutting off the continuity of the supplied paint T can be made unnecessary. This insulating means is not necessarily omitted in the implementation of the electrostatic coating machine of the present invention, and the electrostatic coating machine according to the present invention may be implemented with the insulating means.

  The object to be coated by the electrostatic coating machine according to the present invention may be any object that can be electrostatically coated, such as an automobile body, a body of a track vehicle, a casing of an electric product, and various articles. It may be.

  The electrostatic coating machine according to the present invention can be used for electrostatic coating of various articles in various fields.

7 External paint path 1 Machine T Paint 2 Spraying section, rotary atomizing head 8 Internal paint path 11 High voltage generator X Induction electrode section (charging means)
6 Air motor 6b Rotation output shaft 10 Paint supply tube 4 Shaping air ejection part 3 Air nozzle formation cover

Claims (3)

An internal paint path is installed inside the fuselage to guide the paint supplied to the fuselage through the external paint path to the spray section at the tip of the fuselage.
An electrostatic coating machine provided with charging means for charging the paint sprayed to the outside from the spraying portion with a voltage generated by a high voltage generator,
As the charging means, an induction electrode portion for applying a voltage generated by the high voltage generator is placed in the vicinity of the internal paint path inside the fuselage in a state where it is not in electrical contact with the paint passing through the internal paint path. Place and
By charging the induction electrode part with a voltage applied by the high voltage generator, the paint passing through the internal paint path is charged to a polarity opposite to the polarity of the applied voltage to the induction electrode part by electrostatic induction. , The charging paint is sprayed from the spraying part ,
As the spraying section, a rotary atomizing head that disperses the paint supplied from the internal paint path from the outer peripheral edge by centrifugal force accompanying rotation,
A rotary output shaft of an air motor provided inside the machine body is connected to the rotary atomizing head, and the rotary atomizing head is rotated by the air motor,
A paint supply tube forming the internal paint path is inserted through a central hole in the rotation output shaft of the air motor and passed to the rotary atomizing head;
The paint supply tube and the rotation output shaft of the air motor are formed of an electrical insulating material,
The turbine section of the air motor surrounds the rotation output shaft and the paint supply tube inside the entire circumference of the rotary output shaft and the paint supply tube in a state of being in non-contact with the passing paint of the internal paint path inside the airframe. Placed in a state,
An electrostatic coating machine in which a voltage output terminal of the high voltage generator is electrically connected to the turbine unit, whereby the turbine unit is used as the induction electrode unit . The electrostatic coating machine according to claim 1, wherein the rotary atomizing head is configured to have electrical insulation against charged paint supplied from the paint supply tube . An air nozzle forming cover is provided that forms an outline of the front end of the airframe that is the housing portion of the air motor and forms a shaving air ejection portion between the outer periphery of the rotary atomizing head exposed to the outside through the front end opening,
The electrostatic coating machine according to claim 1 or 2, wherein the air nozzle forming cover is formed of an electrical insulating material .

Images