JPH07116559A - Electrostatic coater - Google Patents

Abstract

PURPOSE:To reduce a coating material cost by optionally supplying various colored coating materials to a rotary atomizing head without making the inside diameter of a tubular rotary shaft of an air motor large, and simultaneously decreasing the loss of the coating material by wash and the loss of the washing solvent even though color change is carried out each time. CONSTITUTION:Ports P1-P12 supplying the various colored coating materials, washing solvent, and washing air respectively are formed by opening at the back side of the machine body 2 with a specified interval along the circumference and a check valve 11 forced to the closing direction is formed at an opening part 8 of each port P1-P12, and a coating material flow passage 7 feeding the coating material to a rotary atmizing head 5 and a rotary joint R which atternotively communicates with the each port P1-P12, are rotationally driven so as to enable positioning to the each port P1-P12. Also a needle 17 releasing the check valve 11 is arranged movably forwards and backwards on a connector 14 attached or detached to the each port P1-P12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint in a rotary atomizing head attached to the tip of the tubular rotary shaft from the tip opening of a paint pipe inserted into the tubular rotary shaft of an air motor built into the machine body. The present invention relates to a center-feed type electrostatic coating machine that supplies a liquid.

[0002]

2. Description of the Related Art A center-feed type electrostatic coating machine includes an electrostatic coating machine 41 and a color changing device 42 as shown in FIG.
Are connected via a paint hose 43, and the paint hose 4
3 is connected to a thin tubular nozzle 46 inserted through a tubular rotary shaft 45 of an air motor 44, and the paint supplied from the paint hose 43 is atomized by rotation when a needle valve formed in the nozzle 46 is opened. The head 47 is electrostatically atomized for coating (see Japanese Utility Model Laid-Open No. 2-112353 and Japanese Utility Model Laid-Open No. 4-91754), and a vehicle body or the like that is successively conveyed by a conveyor is coated. When an object is to be painted with a paint of a predetermined color, the paint of a desired color is supplied from the color changing device 42 to the rotary atomizing head 47 for painting.

When changing the color from the previous color paint to the next color paint, the cleaning air supply valve 48 and the cleaning solvent supply valve 49 provided in the color changing device 42 are alternately opened and closed to wash the cleaning solvent and the cleaning solvent. By supplying air intermittently, the color changing device 42, the paint hose 43, the thin tubular nozzle 46
In addition, the previous color paint remaining and adhering to the rotary atomizing head 47 is washed and removed to prevent color mixture of the previous color paint and the next color paint.

By the way, in a coating line such as an automobile body, since the objects to be coated are not conveyed in the order of the coating colors, the objects to be continuously conveyed are coated with the same color. In most cases, the color change is performed at a rate of about 8 to 9 times while coating 10 objects to be coated. For example, when the white coating is 50%, the red coating is 25%, and the blue coating is 25%, the colors are grouped as white-white-white-white-red-red-blue-blue. Although it is sufficient to change the color twice if it is transported, it is extremely rare that it is actually transported in this way, and it is usually white-red-white-blue-white-red-white-blue. In many cases, they are transported in any order, and in this case, the color must be changed every time the article to be coated arrives.

[0005]

However, when changing colors, the paint hose 43 and the paint of the previous color remaining in the painting machine 41 are always discarded to wash the inside in order to prevent color mixing, so that a huge amount of paint is required. In addition to the loss, a large amount of cleaning solvent is required to clean the inside of the long paint hose 43, and tens of millions of yen worth of paint and solvent must be discarded per year in one stage, which reduces the coating cost. There was a problem of being bulky.

In this case, if a plurality of thin tubular nozzles 46 can be inserted and arranged in the tubular rotary shaft 45, it is possible to reduce paint loss and washing solvent loss, but the thin tubular nozzle 46 with a needle valve is provided. Even if you try to insert multiple
The inner diameter of the tubular rotary shaft 45 is limited, and there is also a limit to downsizing the opening / closing drive mechanism that individually opens and closes each needle valve. Therefore, in the end, a plurality of thin tubular nozzles 46 are installed in the tubular rotary shaft 45. It could not be inserted and arranged. Therefore, according to the present invention, each color paint can be arbitrarily supplied into the rotary shaft of the air motor without increasing the inner diameter of the tubular rotary shaft of the air motor. A technical issue is to reduce paint loss and cleaning solvent loss to reduce paint costs.

[0007]

In order to solve this problem, the present invention relates to a tip end of a tubular rotary shaft from a tip opening portion of a paint pipe inserted through a tubular rotary shaft of an air motor incorporated in a machine body. In an electrostatic coating machine that supplies paint to the installed rotary atomizing head, a paint flow path communicating with the paint pipe is formed on the back side of the machine body, and paint of each color, cleaning solvent and cleaning air Are formed at predetermined intervals along the circumference, and a check valve having a valve body biased in a direction to close the opening is formed at the opening of each port. Is connected to the paint flow channel and the other end is selectively communicated to each port. A rotary joint having a connection flow channel can position the other end side to each port centering on one end side of the connection flow channel. Is driven to rotate At the same time, a connector that is engaged with and disengaged from each of the ports is formed at the other end of the connection flow path, and the valve body of the check valve formed at each port is pressed to open the check valve. It is characterized in that the needle is arranged so as to be able to move forward and backward.

[0008]

According to the present invention, a port for supplying paint, cleaning solvent, and cleaning air is formed on the rear side of the machine body, and each port selectively communicates with the paint flow path via the rotary joint. By advancing the needle with the connector formed on the rotary joint connected to the desired port, the paint is supplied from the port into the rotary atomizing head through the tubular rotary shaft. It is possible to paint with a desired color without inserting a large number of thin tubular nozzles in the rotating shaft.

Further, since the paint flow path for feeding the paint to the tubular rotary shaft is selectively connected to each port through the connection flow path of the rotary joint, the paint is provided on the downstream side of the connector of the rotary joint. Since only the remaining amount and the remaining amount are small, it is sufficient to wash only the downstream side of the connector at the time of color change washing, the paint loss and the washing solvent loss at the time of washing are small, and the washing time is shortened.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on the embodiments shown in the drawings. FIG. 1 is a sectional view showing an electrostatic coating machine according to the present invention, and FIG. 2 is a rear view thereof.

In the figure, reference numeral 1 denotes a rotary mist attached to the tip of the tubular rotary shaft 4 from a tip opening portion of a paint pipe 6 which is inserted in a non-contact state into the tubular rotary shaft 4 of an air motor 3 incorporated in the machine body 2. This is an electrostatic coating machine for supplying paint into the chemical conversion head 5, and a paint flow path 7 communicating with the paint pipe 6 is formed on the back side of the machine body 2, and each color paint, cleaning solvent, and Ports P _{1 to} P to which cleaning air is supplied respectively
₁₂ are formed along the circumference around the opening of the paint flow path 7, and each of the ports P _{1 to} P ₁₂ has a spherical valve in the opening 8 due to the elastic force of the spring 9. A check valve 11 is provided that urges the body 10 to close the opening 8.

One end of R is connected to the paint flow path 7 and the other.
The end is each port P₁~ P₁₂Connection channel that is communicated alternatively
It is a rotary joint equipped with 12,
With the data 13, the center of one end of the connection flow path 12
End side of each port P₁~ P₁₂Is driven to rotate so that
It is arranged to be. The connection channel 12 has one end
The side is in non-contact with the tubular rotary shaft 13a of the indexing motor 13.
And is communicated with the paint flow path 7, and the other end side is
Each port P₁~ P ₁₂Forming a connector 14 that is disengaged from
Has been done.

The connector 14 is composed of a pipe 16 which is advanced and retracted by a cylinder 15 with respect to the opening 8 of each of the ports P _{1 to} P ₁₂ , and an opening is formed at the tip and side surface of the pipe 16 to connect to the opening 8. A needle 17 protruding from its tip is integrally provided in the pipe 16 so as to communicate with the flow path 12. When the pipe 16 is advanced, the tip of the pipe 16 is fitted into the opening 8, and at the same time, the needle 17 presses the valve body 10 to open the check valve 11, and when the pipe is retracted, the tip of the needle 17 is a rotary joint. It is designed to be stored in R.

In the cylinder 15, when the plunger 18 to which the pipe 16 is attached is urged by the spring 19 in the direction of retracting the pipe 16, compressed air is supplied from the air supply port 20 into the cylinder 15. The plunger 18 slides against the elastic force of the spring 19 and the pipe 16 advances. Also, each port P _{1 to} P
_A hose connection port 21 is formed on the outer peripheral side of each of the ports ₁₂ , and the ports P _{1 to} P ₁₁ are connected to paint supply sources of respective colors via paint hoses, and the port P ₁₂ is a cleaning solvent supply valve V.
s and a cleaning air supply valve Va are connected to the cleaning manifold 22. When there are many colors to be used, the paint supply sources of colors that are rarely used may be collectively connected to a color change valve device (not shown), and the color change valve device may be connected to an arbitrary port. .

The above is an example of the configuration of the present invention, and its operation will be described below. For example, a case will be described in which the white paint supplied from the port P ₁ is applied and then the color is changed to the red paint supplied from the port P ₂ . First, when painting with white paint, the indexing motor 13 is driven to rotate, the connector 14 of the rotary joint R is indexed to the port P ₁ , compressed air is supplied to the cylinder 15 and the pipe 16 is advanced, Port P ₁ opening 8
Fit inside.

At this time, the needle 17 formed integrally with the pipe 16 presses the valve body 10 to check the valve 11.
Is opened, the white paint flows out from the port P ₁ , is fed to the rotary atomizing head 5 through the connection flow path 12, the paint flow path 7, and the paint pipe 6, and is electrostatically atomized to be covered with the target material. It is applied to a paint (not shown).

When the white paint finishes and the supply of compressed air to the cylinder 15 is stopped, the pipe 1
6 and needle 17 are retracted so check valve 1
1 is closed and the supply of paint is stopped. Next, the indexing motor 13 is driven to rotate again, the connector 14 of the rotary joint R is indexed to the port P ₁₂ , compressed air is supplied to the cylinder 15 to advance the pipe 16, and the opening 8 of the port P ₁₂ is opened. At the same time as it is inserted into the inside, the solvent supply valve Vs and the air supply valve Va of the cleaning manifold 22 are alternately opened and closed to intermittently supply the cleaning solvent and the cleaning air through the port P ₁₂ and remain on the downstream side of the connector 14. Wash off the white paint.

At this time, since the white paint remains only between the connector 14 and the rotary atomizing head 5, the paint loss at the time of color change is extremely small and the cleaning time can be shortened. When the cleaning is completed, the supply of compressed air to the cylinder 15 is stopped, the pipe 16 is retracted, the indexing motor 13 is driven to rotate again, and this time, the connector 14 of the rotary joint R is connected to the port P _2. And wait until the object to be coated arrives, and when the object to be coated arrives, compressed air is supplied to the cylinder 15, the pipe 16 advances, and the rotary atomizing head 2 is red from the port P ₂ Paint is supplied.

The number of ports is not limited to 12 and can be arbitrarily selected as needed, and one port P
Not only when ₁₂ is connected to the cleaning device 22, for example, if every other port P ₁ , P ₄ , P ₇ , P ₁₀ is connected to the cleaning device, which other ports P ₂ , P ₃ , P _{5 are connected.} , P ₆ ,
P _8, P _9, also be coated with P _11, P _12, it is possible to wash next to the port, the rotary joint R
It is possible to shorten the moving time of the cleaning machine and shorten the entire cleaning time.

The means for moving the pipe 16 back and forth is not limited to the case of using the cylinder 15, and any means can be adopted as long as it can be reciprocally driven by fluid pressure such as a diaphragm or a bellows. . further,
The needle 17 is not limited to being integrally attached to the pipe 16, but may be reciprocally driven by separate cylinders, or may be omitted by forming the needle 17 itself into a tubular shape and also serving as the pipe 16. May be.

FIG. 3 is a sectional view showing a main part of another electrostatic coating machine according to the present invention. In this example, each color paint is applied to each of the ports P _{1 to} P ₁₂ formed in the coating machine 1. Is supplied and is connected to the cleaning manifold 22 provided with the cleaning solvent supply valve Vs and the cleaning air supply valve Va.
Is formed on the rotary joint R. The cleaning port Pc is communicated with the inside of the connector 14 through the cleaning flow path 23, and the pipe 16 is retracted to cause the paint supply port Pc.
_When the check valves 11 of _{1 to} P ₁₂ are closed, they are opened in the connector 14, and a needle valve 26 that is opened and closed by a needle 25 advanced and retracted by a cylinder 24 is provided in the middle of the cleaning flow path 23. Has been formed.

When the pipes 16 and 17 are retracted by the cylinder 15 after the coating is completed, the check valve 11 formed in the coating machine 1 is closed and, at the same time, the cleaning port Pc and the connector are connected via the cleaning flow path 23. 14 communicate with each other, and the needle 24 is retracted by the cylinder 24 to open the cleaning flow path 23. In this state, by alternately opening and closing the cleaning solvent supply valve Vs and the cleaning air supply valve Va, the cleaning solvent and the air are supplied into the connector 14, so that the rotary joint R is moved according to this example. Without the need for cleaning the downstream side of the connector 14 on the spot.

[0023]

As described above, according to the present invention, by rotating the rotary joint to index the connector and connect it to an arbitrary port, the inner diameter of the tubular rotary shaft of the air motor is increased and a large number of thin tubes are provided. It is possible to paint with a paint of any color without inserting the nozzle in the rotary shaft, and at the same time, even if the color is changed every time, a small amount of paint that remains only on the downstream side of the connector can be removed. It can be discarded, and the amount of paint that must be discarded by cleaning and the amount of cleaning solvent used for cleaning can be reduced, reducing the coating cost and at the same time the cleaning time can be shortened. Have.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an electrostatic coating machine according to the present invention.

FIG. 2 is a rear view thereof.

FIG. 3 is a sectional view showing a main part of another electrostatic coating machine according to the present invention.

FIG. 4 is a flow sheet showing a conventional device.

[Explanation of symbols]

1 ... electrostatic coating machine 2 ... body 3 ... air motor 4 ... tubular rotary shaft 5 ... rotary atomizing head 6 ... paint pipe 7 ... paint passage P ₁ to P ₁₂ ... Port 8 ... Port opening 10 ... Valve body 11 ... Check valve R ... Rotary joint 12 ... Connection flow path 14 ... Connector 15 ... Cylinder 17 ... ..Needle Pc ... Washing port

Claims (2)

[Claims] 1. A rotary mist attached to the tip of the tubular rotary shaft (4) from a paint pipe (6) inserted through a tubular rotary shaft (4) of an air motor (3) built into the machine body (2). In the electrostatic coating machine for supplying the paint into the chemical head (5), the paint pipe (6) is provided on the back side of the machine body (2).
A paint flow path (7) communicating with the opening is formed, and a port for supplying paint of each color, cleaning solvent and cleaning air, respectively.
(P _{1 to} P ₁₂ ) are formed at predetermined intervals along the circumference, and the openings (8) of the respective ports (P _{1 to} P ₁₂ ) are formed in a direction to close the opening (8). A check valve (11) having a biased valve body (10) is formed, one end of which communicates with the paint passage (7) and the other end of which selectively communicates with each port (P _{1 to} P ₁₂ ). rotary joint having a connecting channel (12) which is (R) is positionable rotating the other end around one end of the connecting channel (12) in each port (P ₁ to P _{1 2)} A connector (14) that is driven and is engaged with and disengaged from each of the ports (P _{1 to} P ₁₂ ) is formed on the other end side of the connection flow path (12). Patent that the port needle for opening the valve body (10) to press the with check valve (11) of (P ₁ to P ₁₂₎ which is formed in the check valve (11) (17) in such a manner that it can advance and retreat Electrostatic coating machine to be. 2. A rotary mist attached to the tip of the tubular rotary shaft (4) from a paint pipe (6) inserted through the tubular rotary shaft (4) of an air motor (3) built into the machine body (2). In the electrostatic coating machine for supplying the paint into the chemical head (5), the paint pipe (6) is provided on the back side of the machine body (2).
A paint flow path (7) communicating with the above is formed, and ports (P _{1 to} P ₁₂ ) for supplying paint of each color are formed along the circumference at predetermined intervals, and each of the ports (P ₁ to P ₁₂ ) is formed. A check valve (11) having a valve body (10) biased in a direction of closing the opening (8) is formed in the opening (8) of P ₁₂ ), and one end of the check valve (11) has the paint flow path ( 7) and a rotary joint (R) provided with a connection channel (12) which is communicated with the other ends of the ports (P _{1 to} P ₁₂ ) as an alternative. On the other side of each port (P ₁ ~ P
₁₂ ) is rotationally driven so that it can be positioned in the connection channel (1
On the other end side of 2), a connector (14) that is engaged with and disengaged from each of the ports (P _{1 to} P ₁₂ ) is formed, and the connector (14) includes
Check valve (11) formed on each port (P _{1 to} P ₁₂ ).
A needle (17) for pressing the valve body (10) to open the check valve (11) is arranged so as to be movable back and forth, and the needle (17) is retracted to close the check valve (11). In the electrostatic coating machine, a cleaning port (Pc) for supplying a cleaning solvent and cleaning air into the connector (14) is formed in the rotary joint (R).