JP2988318B2 - Rotary atomizing electrostatic coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary atomizing electrostatic coating apparatus capable of switching a coating color, and more particularly to a rotary atomizing electrostatic coating apparatus capable of preventing the occurrence of color mixing during upward coating. Related to a coating device.

[0002]

2. Description of the Related Art Since the paint color of a vehicle body varies depending on specifications,
In the body painting line, the color of the paint is automatically switched. In the painting line, painting work is performed using a rotary atomizing electrostatic coating device to increase the efficiency of applying paint to the car body.This rotary atomizing electrostatic coating device also has a color change function. ing.

[0003] In a rotary atomizing electrostatic coating apparatus, paint is supplied to an atomizing head attached to the tip of a rotating shaft, and the paint is atomized by centrifugal force due to high-speed rotation of the atomizing head. The fine particles of the coating material are applied to the object to be coated by a suction force caused by an electrostatic field between the object and the object to be coated. Japanese Patent Application Laid-Open No. 6-134354 discloses a rotary atomizing electrostatic coating apparatus in which a plurality of paint nozzles are arranged in a hollow portion of a rotating shaft in order to save paint and cleaning agents when changing paint colors. I have.

FIGS. 7 to 10 show an example of a conventional rotary atomizing electrostatic coating apparatus. As shown in FIG. 7, an outer tube 3 is disposed in the hollow portion 2 of the rotating shaft 1. Outer tube 3
The paint nozzles 4, 5, 6, and 7 are arranged inside. Each paint nozzle 4, 5, 6, 7 projects a predetermined amount from the downstream end surface of the outer tube 3. At the downstream end of the outer tube 3, an introduction guide 8 for positioning each of the paint nozzles 4, 5, 6, 7 is provided.
Is provided. The paints 11 and 12 of different colors can be supplied to the paint nozzles 4 and 6, and when the paint is supplied to one paint nozzle 4, the supply of the paint by the other paint nozzle 6 is stopped. Outer tube 3 and paint nozzles 4, 5,
The space between 6 and 7 is formed in a cleaning agent passage 10 to which the cleaning agent is supplied.

Since the rotary atomizing electrostatic coating apparatus shown in FIG. 7 has a plurality of paint nozzles, it is only necessary to supply paint from a paint nozzle corresponding to a specific paint color. There is no need to extrude and discharge the paint in the paint nozzle. In addition, the paint adhered to the atomizing head attached to the tip of the rotating shaft is washed by the cleaning agent discharged from the end of the outer tube through the cleaning agent passage.

[0006]

However, in the rotary atomizing electrostatic coating apparatus shown in FIG. 7, it is difficult to provide a valve for supplying and stopping paint at the tip side of the paint nozzle. The following problems occur when the paint is poorly cut at the time of stopping and is applied upward. FIG. 9 shows a state in which the rotary atomizing electrostatic coating apparatus of FIG. 7 is used to perform upward coating. When the supply of the paint 11 is stopped in the upward painting state, the paint 11 drips from the tip of the paint nozzle 4 toward the introduction guide 8 as shown in FIG. Paint 11
The amount of dripping becomes particularly large when the number of supply of the paint 11 is large or when the paint runs out poorly. Dripping paint 1
1 flows back into the cleaning agent passage 10 through the introduction guide 8 due to the influence of gravity, and causes color mixing. Also,
The dripping paint 11 adheres also to the end face of the introduction guide 8, but the cleaning agent does not sufficiently contact the end face of the introduction guide 8, so that the paint adhered to the end face cannot be cleaned, and other colors of other colors cannot be washed. When the paint 12 is supplied, the paint 11 attached to the end face of the introduction guide 8 mixes with other paints 12 and color mixing occurs.

Conventionally, in order to prevent color mixing due to paint dripping, when starting upward painting, the paint is discharged in a state where the apparatus is in a downward attitude in advance, and after the upward painting is completed, the painting is performed. It was necessary to stop the supply of the paint by changing the posture downward. Therefore, it is necessary to supply useless paint, and there is a problem that the amount of paint used increases. Further, in order to prevent the paint from dripping toward the introduction guide side in the upward painting, it is necessary to limit the upward angle to within a predetermined value, and there has been a restriction on the painting operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotary atomizing electrostatic coating apparatus capable of preventing the occurrence of color mixing due to the supply and stop of the paint during upward coating.

[0009]

The rotary atomizing electrostatic coating apparatus according to the present invention that achieves this object is as follows. An outer tube is arranged in the hollow portion of the rotary shaft to which the atomizing head is attached, and a plurality of paint nozzles are provided inside the outer tube, the tips of which protrude from the downstream end of the outer tube. Between
A cleaning agent passage for supplying compressed air except when the atomizing head is cleaned by supplying a cleaning agent, and a plurality of paint nozzles are respectively inserted inside the outer tube and function as a part of the cleaning agent passage. A rotary atomizer having a hole, and an introduction guide for positioning the paint nozzle substantially at the center of the hole, and disposing the introduction guide at a position away from the downstream end of the outer tube to the upstream side. Electrostatic coating equipment.

[0010]

In the rotary atomizing electrostatic coating apparatus according to the present invention, compressed air is supplied to the cleaning agent passage except when the atomizing head is cleaned, so that the pressure in the cleaning agent passage can be increased, It is possible to push back the paint from the paint nozzle which tends to flow into the cleaning agent passage at the time of the upward coating, so that the color mixture caused by the flowing of the paint into the cleaning agent passage is eliminated. Since the introduction guide is located at a position away from the downstream end of the outer pipe to the upstream side, even if the paint drips from the paint nozzle when the supply of paint is stopped, the paint should adhere to the introduction guide. And the dripping paint is discharged to the outside by compressed air from the cleaning agent passage. Since the introduction guide positions the paint nozzle substantially at the center of the hole functioning as a part of the cleaning agent passage, a circumferentially uniform gap is formed on the outer periphery of the paint nozzle of the introduction guide. Therefore, the compressed air flowing through the hole of the introduction guide has a uniform distribution, and a stable compressed air flow can be formed at the tip of the paint nozzle.

[0011]

1 to 6 show an embodiment of the present invention. In FIG. 3, reference numeral 20 denotes a rotary atomizing electrostatic coating apparatus. The rotary atomizing electrostatic coating apparatus 20 has an air motor 22 for rotating a hollow rotary shaft 21 at high speed. An atomizing head 23 for scattering paint by rotation is attached to the tip of the rotating shaft 21. An outer tube 24 extending along the center of rotation of the rotating shaft 21 is provided in the hollow portion 21 a of the rotating shaft 21. One of the outer tubes 24 is fixed to a case (not shown) that holds the air motor 22 and the like. Four paint nozzles 26 are provided inside the outer tube 24. Each paint nozzle 26 extends along the outer tube 24, and has a distal end projecting from the downstream end of the outer tube 24. The other of the paint nozzles 26 is fixed to the case.

At the upstream end of each paint nozzle 26, a dedicated paint hose 30a, 30b, 30c, 30d is connected. Each paint hose 30a, 30b, 30c, 30d
Is connected to a paint valve 31 for supplying and stopping the paint, and a suction valve 32 for pulling back the paint supplied to each paint nozzle 26 by a certain amount. Outer tube 2
A hose 33 is connected to an upstream end of the hose 4. The upstream end of the hose 33 is connected to a cleaning valve 35 for supplying and stopping the cleaning agent 40 and an air valve 36 for supplying and stopping the compressed air 41. In the present embodiment, as shown in FIG. 1, paints 45 and 46 having different colors are supplied to two paint nozzles 26 among the four paint nozzles 26.

The space between the outer tube 24 and each paint nozzle 26 is connected to a cleaning agent passage 37 through which a cleaning agent 40 supplied through a cleaning valve 35 and a compressed air 41 supplied through an air valve 36 flow. Is formed. Cleaning agent passage 37
, Only the compressed air 41 is supplied except when cleaning the atomizing head 23 and the tip of each paint nozzle 26 by the supply of the cleaning agent 40. In this embodiment, the rotating shaft 21 and the outer tube 2
The compressed air 42 is also supplied from a gap between the compressed air 42 and the compressed air 42.

An introduction guide 50 is provided inside the outer tube 24. The introduction guide 50 is fixed to the outer tube 24. The introduction guide 50 may be configured to be integrally formed with the outer tube 24 or may be configured to be pressed into the outer tube 24 from one side. Further, an attachment structure shown in a modified example described later may be used. The introduction guide 50 includes each paint nozzle 2
A hole 51 into which each 6 is inserted is formed. Hole 5
1 is in communication with the cleaning agent passage 37,
Functioning as part of A plurality of positioning projections 52 projecting inward in the radial direction are formed on the periphery of the hole 51. In this embodiment, the number of the positioning projections 52 is three, and each of the positioning projections 52 is disposed at a position equally divided into three in the circumferential direction. The sectional area of the positioning projection 52 is
It is desirable that the size be as small as possible from the viewpoint of securing the flow path cross-sectional area. The paint nozzle 26 is positioned by each positioning protrusion 52 such that the center in the radial direction substantially matches the center of the hole 51. The introduction guide 50 is disposed at a position away from the downstream end of the outer tube 24 by a distance X toward the upstream side.

FIGS. 4 to 6 show modifications of the introduction guide of FIG. As shown in FIG.
Holes 61 into which the seven paint nozzles 26 are inserted respectively
Are formed. One of the holes 61 is formed at the radial center of the introduction guide 60. The other six holes 61 are located on the outer periphery of the one hole 61, and are arranged at positions equally divided into six in the circumferential direction. At the periphery of the hole 61, a positioning projection 62 projecting inward in the radial direction is formed by machining using an end mill or the like. Each paint nozzle 26 is positioned by each positioning protrusion 62 such that the center in the radial direction substantially coincides with the center of the hole 61. At both ends in the axial direction of the introduction guide 60,
4 are formed. As shown in FIG.
0 is provided in the middle of the outer tube 24 and the introduction guide 6
The outer tube 24 is fitted into each of the 0 spigot portions 64.

Next, the operation of the above-mentioned rotary atomizing electrostatic coating apparatus will be described. When the object to be coated is positioned at a predetermined position, a coating operation by the rotary atomizing electrostatic coating device 20 is started. In this case, a coating color based on the specification of the object to be coated is selected, and only the corresponding coating valve 31 is opened. When a specific paint valve 31 opens,
A paint 45 is pumped from a paint supply source (not shown) to a specific paint nozzle 26, and is sprayed from the tip of the paint nozzle 26 to the atomizing head 2.
The paint 45 is supplied to the inner surface side of 3. Since the atomizing head 23 is rotated at a high speed by the air motor 22, the paint 45 attached to the inner wall surface of the atomizing head 23 is scattered radially outward as particles.

The lower surface side of the object to be coated is coated by upward coating as shown in FIG. Since the compressed air 41 is supplied to the cleaning agent passage 37 except when the atomizing head 23 is cleaned, the pressure in the cleaning agent passage 37 can be increased,
It is possible to push back the paint 45 from the paint nozzle 26 that is going to flow into the cleaning agent passage 37 during upward painting. Therefore, the cleaning agent passage 37 at the time of upward painting is used.
The paint 45 is prevented from flowing into the paint 45, and the color mixture due to the flow of the paint 45 is eliminated.

When the painting operation is completed, the paint valve 3
1 is closed, and the supply of the paint 45 to the paint nozzle 26 is stopped. In this case, since the paint valve 31 is disposed at a position away from the tip of the paint nozzle 26, even when the supply of the paint 45 is stopped by closing the paint valve 31, the paint runs out poorly. The paint 45 drips from the tip of the paint nozzle 26 toward the introduction guide 50. Since the introduction guide 50 is disposed at a position away from the downstream end of the outer tube 24 by the distance X on the upstream side, even when the paint 45 drips from the paint nozzle 26 when the supply of the paint 45 is stopped, the The paint 45 does not adhere to the introduction guide 50, and the dripping paint 45 is discharged to the outside by the compressed air 41 from the cleaning agent passage 37.

The introduction guide 50 has three positioning projections 52 for positioning the paint nozzle 26 substantially at the center of the hole 51 functioning as a part of the cleaning agent passage 37. A gap is formed on the outer periphery of the outer peripheral surface of the outer peripheral surface, which extends uniformly in the circumferential direction. Therefore, the compressed air 41 flowing through the hole 51 of the introduction guide 50 has a substantially uniform distribution in the circumferential direction, and is located on the outer periphery of the tip end of the paint nozzle 26 as compared with the conventional positioning of the paint nozzle by the introduction guide 8 shown in FIG. , A stable flow of the compressed air 41 is formed. Therefore, even when the paint 45 drips from the paint nozzle 26 toward the introduction guide 50, the paint 45 can be reliably discharged by the compressed air 41.

When the supply of the paint 45 is stopped by the paint valve 31, the suction valve 32 is operated and the paint 45 supplied to the paint nozzle 26 is pulled back by a certain amount. The amount of 45 is also suppressed. After the supply of the paint 45 is stopped, the cleaning valve 35 is opened and the air valve 36 is closed. As a result, the cleaning agent 40 is supplied to the cleaning agent passage 37, and the inner peripheral surface of the atomizing head 23 is discharged from the downstream end of the outer tube 24.
Is washed by. Since the tip of each paint nozzle 26 slightly protrudes from the downstream end of the outer pipe 24, the tip of the paint nozzle 26 is also cleaned by the cleaning agent 40 discharged from the outer pipe 24. Even if the paint 45 adheres to the introduction guide 50, the attached paint 45 can be washed away by the detergent 40 because the introduction guide 50 is disposed in the middle of the detergent passage 37.

When the object to be coated is coated with the paint 46 of a different color, a specific paint valve 31 corresponding to the paint 46 is opened, and the paint 46 is supplied to another paint nozzle 26. Here, the compressed air 41 is supplied to the cleaning agent passage 37 except when the atomizing head 23 is washed, so that the coating material 46 discharged from the coating nozzle 26 does not flow into the cleaning agent passage 37 side. Further, since the paint 45 at the time of the previous coating does not adhere to the introduction guide 50, the occurrence of color mixing is reliably prevented. Therefore, even when the paint is supplied and stopped in the upward posture, the occurrence of the color mixture is eliminated, and the upward painting operation can be improved.

[0022]

According to the rotary atomizing electrostatic coating apparatus according to the present invention, cleaning between the outer tube and each coating nozzle is performed by supplying compressed air except when cleaning the atomizing head by supplying a cleaning agent. With the agent passage, inside the outer tube, each paint nozzle is inserted and has a plurality of holes that function as a part of the cleaning agent passage, and an introduction guide that positions the paint nozzle at the center of this hole is provided,
Since the introduction guide is located at a position away from the downstream end of the outer tube to the upstream side, even if the paint is supplied and stopped during upward coating, the paint flows into the cleaning agent passage and to the paint introduction guide. Can be prevented, and the occurrence of color mixture can be prevented. Therefore, as in the past, when starting upward painting, it is necessary to discharge the paint while the apparatus is in a downward position in advance, and after the upward painting is completed, change the painting position to downward and stop the supply of paint. Is also gone. Therefore, unnecessary supply (overspray) of paint can be eliminated, and the amount of paint used can be reduced. Further, since the upward angle in the upward coating is not limited, the restrictions on the coating operation are reduced, and the coating operation efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part of a rotary atomizing electrostatic coating apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a schematic configuration diagram of the rotary atomizing electrostatic coating device of FIG. 1;

FIG. 4 is a front view showing a modification of the introduction guide of FIG. 2;

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a partially enlarged front view of FIG. 4;

FIG. 7 is an enlarged sectional view of a main part of a conventional rotary atomizing electrostatic coating apparatus.

FIG. 8 is a sectional view taken along line CC of FIG. 7;

FIG. 9 is a cross-sectional view showing a state of upward painting by the apparatus of FIG. 7;

FIG. 10 is an enlarged sectional view taken along line DD of FIG. 9;

[Explanation of symbols]

 Reference Signs List 20 rotary atomizing electrostatic coating device 21 rotating shaft 23 atomizing head 24 outer tube 26 paint nozzle 37 cleaning agent passage 50 introduction guide 51 hole 60 introduction guide 61 hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B05B 5/04 B05B 5/08

Claims (1)

(57) [Claims] 1. An outer tube is disposed in a hollow portion of a rotary shaft to which an atomizing head is attached, and a plurality of paint nozzles having a tip end projecting from a downstream end of the outer tube are provided inside the outer tube. A space between the pipe and each paint nozzle is a cleaning agent passage for supplying compressed air except when the atomizing head is cleaned by supplying a cleaning agent, and each paint nozzle is inserted inside the outer pipe, and the cleaning is performed. A plurality of holes functioning as part of the agent passage are provided, and an introduction guide for positioning the paint nozzle is provided substantially at the center of the hole. A rotary atomizing electrostatic coating device, which is arranged.