JPH07213957A - Electrostatic coater - Google Patents

Abstract

PURPOSE:To lessen the loss of a coating compound due to washing and the cleaning solvent loss and to lessen the coating cost even in the case color is changed and washing is carried out every time by installing a plurality of coating compound supplying valves, which are opened and closed individually, in a device. CONSTITUTION:A circular flow route 7 whose one end is connected with a rear end side of a coating compound supplying pipe 5 inserted into a tubular rotary axle 4 and the other end is connected with a cleaning valve to supply a cleaning solvent and cleaning air is formed in the back side of an air motor 3 built in this electrostatic coater 2 along the circumferential direction and coating compound supplying valves V1-V7 connected with supplying sources of respective color coating compounds are installed along the circular flow route 7 and are connected with the flow route 6 from the back side of the coater 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center feed type electrostatic coating for supplying paint from a tip opening portion of a tubular rotary shaft of an air motor incorporated in a machine body into a rotary atomizing head attached to the tip thereof. Regarding the machine.

[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 the color change from the previous color paint to the next color paint is performed, the cleaning solvent supply valve 48 and the cleaning air supply valve 49 provided in the color changing device 42 are alternately opened and closed to clean 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 an automobile body coating line, since the automobile bodies to be coated are not conveyed in a group in the order of the coating colors, the same is continuously applied to the continuously conveyed substrates. There is almost no case where color coating is performed, and in the present situation, the color is changed at a rate of 8 to 9 times while coating 10 objects to be coated. For example, 50% white paint, 25% red paint, 25% blue paint
In the case of being transported at a ratio of, if the colors are collectively transported such as white-white-white-white-red-red-blue-blue, it is sufficient to change the color twice. It is extremely rare to be transported, and normally, white-red-white-blue-
Since they are conveyed in any order such as white-red-white-blue, the color is changed every time the coated object arrives.

[0005]

However, in order to prevent color mixing when changing colors, the previous color paint remaining in the paint hose 43 or the like is discarded every time cleaning is performed. As a result, not only does a huge paint loss occur, but also a large amount of cleaning solvent is required to clean the interior of the long paint hose 43, and tens of millions of yen of paint and solvent are thrown away in one stage per year. However, there is a problem that the coating cost increases.

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. It was difficult to insert and arrange. In view of this, the present invention reduces the paint loss due to washing and the loss of washing solvent even when a plurality of paint supply valves that are individually driven to open and close are provided in the machine to perform color change washing every time, thus reducing the paint cost. The technical challenge is to be able to mitigate.

[0007]

In order to solve this problem, the present invention is directed to a tip of the tubular rotary shaft through a paint supply pipe inserted into the shaft of the tubular rotary shaft of an air motor incorporated in the machine body. In an electrostatic coating machine that supplies paint to the attached rotary atomizing head, on the back side of the air motor,
Along the circumferential direction, an annular flow path is formed in which one end is connected to the rear end side of the paint supply pipe, and the other end is connected to a cleaning valve that supplies cleaning solvent and cleaning air. A paint supply valve connected to a paint supply source is arranged along the annular flow path, and is connected to the flow path from the back side of the machine body.

[0008]

According to the present invention, since each paint supply valve is connected to the annular flow path connected to the paint supply pipe inserted into the shaft of the tubular rotary shaft of the air motor, the paint supply valves are dispersed in an annular shape. Therefore, it can be arranged on the circumferential portion of the machine body with a sufficient space. Then, when the desired paint supply valve is opened, the paint of the desired color supplied from the valve is supplied into the rotary atomizing head from the paint supply pipe communicating with the annular flow path. Also, since each paint supply valve is connected to the annular flow path formed inside the fuselage, at the end of painting, the paint remains only in the annular flow path and the paint supply pipe, and the remaining amount is very small. At the time of replacement cleaning, it suffices to clean only the inside of the annular flow path and the inside of the paint supply pipe, the paint loss and the cleaning solvent loss at the time of cleaning are small, and the cleaning time is shortened.

[0009]

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 FIG. 1, reference numeral 1 denotes a rotary atomizing head 6 attached to the tip of the tubular rotary shaft 4 from the tip opening portion of a paint supply pipe 5 inserted into the tubular rotary shaft 4 of an air motor 3 incorporated in the machine body 2. An electrostatic coating machine for supplying paint into the interior, wherein one end 7a is connected to the rear end side of the paint supply pipe 5 on the back side of the air motor 3, and the other end 7b is supplied with cleaning solvent and cleaning air. Annular flow path 7 to which the cleaning valve V _{0 to} be supplied is connected
Are formed.

Inside the machine body 2, paint supply valves V _{1 to} V ₆ for independently supplying paints of frequently used colors such as white, red, gray and blue, and paints of rarely used colors are selected. A paint supply valve V ₇ connected to a color changing device (not shown) that is electrically supplied is disposed along the annular flow path 7 and is connected to the annular flow path 7 from the back side of the machine body 2. Each of the paint supply valves V _{1 to} V ₇ and the cleaning valve V ₀ is formed as a needle valve that opens and closes the nozzle hole 8 with a needle 9, and is annularly arranged along the flow path 7 on the back side of the machine body 2. It is opened and closed by cylinders (valve drive parts) S _{1 to} S ₇ and S ₀ . Each of the cylinders S _{0 to} S ₇ biases the needle 9 connected to the plunger 10 in the direction of closing the nozzle hole 8 by the spring 11, and the cylinders S _{0 to} S _{7 are} supplied from the air supply port 12.
When compressed air is supplied inside, the plunger 10 slides against the elastic force of the spring 11, the needle 9 retracts, and the nozzle hole 8 opens.

Further, in the present embodiment, the tip of the paint supply pipe 5 is formed into a needle shape and is inserted into the waste liquid pipe 13 which is inserted into the tubular rotary shaft 4 of the air motor 3, and the center of the rear side of the machine body 2 is inserted. The needle valve 1 is configured to open and close the paint discharge port 14 formed at the tip of the waste liquid pipe 13 by the cylinder Sp arranged in
5, the waste liquid outlet 1 formed at the rear end of the waste liquid pipe 13
6 is opened and closed. The paint supplied from the paint supply pipe 5 is supplied to the rotary atomizing head 6 by opening the paint discharge port 14 during coating, and the paint supply port 5 is closed by closing the paint discharge port 14 during cleaning. The waste liquid to be fed passes through the waste liquid pipe 13 and is discharged to a waste liquid tank (not shown).

The above is an example of the configuration of the present invention, and its operation will be described below. For example, the case where the white paint supplied by the paint supply valve V ₁ is changed to the red paint supplied by the paint supply valve V ₂ will be described. First, when painting with white paint, compressed air is supplied to the cylinder S ₁ to slide the plunger 10 backwards against the elastic force of the spring 11, and the needle 9 is pulled to move the paint supply valve V ₁ At the same time when the nozzle hole 8 is opened, compressed air is supplied to the cylinder Sp to pull the paint supply pipe 5 and open the paint discharge port 14. As a result, the white paint is supplied from the paint supply valve V ₁ to the rotary atomizing head 6 via the annular flow path 7 and the paint supply pipe 5, electrostatically atomized, and applied to an object to be coated (not shown). Be worn.

When the white paint is finished,
The supply of compressed air to the cylinders S ₁ and Sp is stopped, the paint discharge port 14 and the paint supply valve V ₁ are closed, and this time,
Open the flush valve V ₀ and waste outlet 16 to supply compressed air to the cylinder S ₀ and 17, the cleaning solvent and wash air which is delivered from the flush valve V _0, the flow path 7 and the paint supply tube 5 The remaining white paint is washed off and discharged from the waste liquid outlet 16.

At this time, since the cleaning valve V ₀ is connected to the end of the annular flow path 7, the paint remaining in the annular flow path 7 can be cleaned cleanly and no color remains. Further, since it is sufficient to wash the inside of the annular flow path 7 and the paint supply pipe 5, the amount of washing solvent required for washing is small, the washing time is short, and the loss of white paint remains in these. Since it is only, there is very little paint loss when changing colors.

Next, the supply of the compressed air to the cylinder 17 is stopped and the waste liquid outlet 16 is closed. At the same time, the compressed air is supplied to the cylinder Sp to open the paint discharge port 14 and wash the rotary atomizing head 6. To do. When cleaning is completed, cylinder S
The supply of compressed air to ₀ and Sp is stopped and the cleaning valve V
₀ and the paint discharge port 14 are closed, and when the object to be coated arrives, this time, the paint supply valve V ₂ and the paint discharge port 14 that supply compressed air to the cylinders S ₂ and Sp to supply the red paint are opened. Then apply the next color paint.

The paint supply valves V _{1 to} V ₇ are not limited to the case of being formed in the direction perpendicular to the tubular rotary shaft 4, but may be formed in a radial shape by arranging them on a conical surface with a slight inclination. Good. Also, the cylinder S ₁
Not limited to the case of using ~ S ₇ , if it is reciprocally driven by fluid pressure, such as a diaphragm or bellows,
Any means can be adopted.

Further, the case has been described in which the cleaning solvent and cleaning air are supplied from the cleaning valve V ₀ connected to the end of the annular flow path 7 and the color changing device is connected to the coating material supply valve V _7. Other paint supply valve V _{1 for} V ₇
~V ₆ and supplied solely similarly frequently used paint, connect the color change device to the cleaning valve V _0, when supplying the low color of the paint used frequently from the valve V ₀ at the same time, the color change The inside of the annular flow path 7 and the paint supply pipe 5 may be cleaned with the cleaning solvent and the cleaning air supplied to the apparatus.

[0019]

As described above, according to the present invention, an annular flow passage is connected to a paint supply pipe inserted into the tubular rotary shaft of an air motor, and each paint supply valve is connected to the annular flow passage. Since it is provided, it is possible to disperse the paint supply valve in an annular shape and arrange it in the circumferential portion of the machine body with space, and since the annular flow path is formed in the machine body, color change cleaning is possible. This has a very excellent effect that the amount of the paint to be discarded when performing the cleaning and the amount of the cleaning solvent used for cleaning can be reduced to reduce the coating cost.

[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 of the main part.

FIG. 3 is a flow sheet showing a conventional device.

[Explanation of Codes] 1 ... Electrostatic coating machine 2 ... Machine body 3 ... Air motor 4 ... Tubular rotating shaft 5 ... Paint supply pipe 6 ... Rotating atomizing head 7 ... Ring Flow path V ₀ ··· Wash valve V _{1 to} V ₇ ··· Paint supply valve 8 ··· Nozzle hole 9 · Needle

Claims (1)

[Claims] 1. Attached to the tip of the tubular rotary shaft (4) through a paint supply pipe (5) inserted into 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 rotary atomizing head (6), one end (7a) is provided on the back side of the air motor (3) along the circumferential direction of the paint supply pipe (5). An annular flow path (7) is formed which is connected to the rear end side of the same and is connected to the other end (7b) of a cleaning valve (V ₀ ) for supplying a cleaning solvent and cleaning air. Paint supply valves (V _{1 to} V ₆ ) connected to the flow path (7) are arranged along the annular flow path (7) and are connected to the flow path (7) from the back side of the machine body (2). An electrostatic coating machine characterized by.