JP3223028B2 - Electrostatic coating machine - Google Patents

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 feeder for supplying paint into a paint chamber of a rotary atomizing head attached to the end of a tubular rotary shaft of an air motor built in an airframe. Related to the coating machine.

[0002]

2. Description of the Related Art As shown in FIG. 5, a center feed type electrostatic coating machine is provided with a color changing device 42 as an electrostatic coating machine.
Is 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 rotationally atomizes the paint supplied from the paint hose 43 when a needle valve formed in the nozzle 46 is opened. The spraying is performed by electrostatic atomization with the head 47 (see Japanese Utility Model Application Laid-Open No. 2-112353 and Japanese Utility Model Application Laid-Open No. 4-91754). When an object is painted with a paint of a predetermined color, a paint of a desired color is supplied from the color changing device 42 to the rotary atomizing head 47 for painting.

When a color change is made from the previous color paint to the next color paint, 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, and the cleaning solvent and the cleaning By intermittently supplying air, the color changing device 42, the paint hose 43, and the capillary nozzle 46 are provided.
In addition, the previous color paint remaining and adhering to the rotary atomizing head 47 is washed and removed to prevent the color mixture of the previous color paint and the next color paint.

[0004] In an actual automobile body coating line, the objects to be coated are rarely transported collectively for each coating color. There is almost no case of painting with 10
At present, the color is changed at a rate of about 8 to 9 times during the coating of the object to be coated. For example, if the white paint is 5
In the case where 0%, red paint is 25%, and blue paint are 25%, if they are conveyed as a group for each color, such as white-white-white-white-red-red-blue-blue, Color change is 2
It suffices, but it is extremely rare that it is actually conveyed in this way, and usually it is conveyed in random order as white-red-white-blue-white-red-white-blue. The color is changed every time the object arrives.

[0005]

However, at the time of color change, cleaning must be performed to prevent color mixing.
Each time cleaning is performed, the pre-color paint remaining in the paint hose 43 or the like is discarded, so that not only enormous paint loss occurs but also a large amount of cleaning solvent is required to clean the long paint hose 43. It is necessary to throw away tens of millions of yen of paint and solvent per year in one stage, and there is a problem that the coating cost increases.

[0006] Therefore, even when the color change is performed every time, the present applicant has proposed a method of reducing a paint loss due to washing and a loss of a washing solvent to reduce paint cost by reducing a plurality of paints in a tubular rotary shaft. An electrostatic coating machine in which a thin tubular nozzle is inserted and arranged in a ring shape has been proposed (Japanese Patent Application Nos. 5-244164 to 244167).
No.), however, as a result of further experiments, it was difficult to wash the paint adhered to the tip of the thin-tube nozzle, and there was a new problem of causing color mixing if washed within a limited time. Therefore, the present invention is to reduce the paint loss and the washing solvent loss due to washing to reduce the paint cost, and at the same time to make it possible to wash the nozzle holes of each of the thin tubular nozzles that are difficult to wash in a short time. It is an issue.

[0007]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a paint chamber of a rotary atomizing head attached to the tip of a tubular rotary shaft of an air motor built in an airframe. In an electrostatic coating machine that supplies paint through a shaft, a plurality of thin tubular nozzles that open and close nozzle holes with wires or needles respectively connected to valve drive units provided on the machine body are provided in the shaft of the tubular rotary shaft. Are inserted in a non-contact state into the coating chamber of the rotary atomizing head, and are arranged annularly in the coating chamber, and the cleaning solvent and the cleaning air are directed toward the front side of the coating chamber at the center position of the annularly arranged thin tubular nozzle. A cleaning nozzle for spraying and spraying the nozzle toward the nozzle hole of each of the thin tubular nozzles formed therearound is provided.

[0008]

According to the present invention, at the time of coating, by opening the nozzle hole of a desired thin-tube nozzle, paint of a desired color is directly supplied from the nozzle hole of the thin-tube nozzle into the paint chamber of the rotary atomizing head. Therefore, at the end of the coating, the paint adheres to the inner wall of the paint chamber of the rotary atomizing head and the nozzle hole of the narrow nozzle.

Here, when the cleaning solvent and the cleaning air are alternately supplied from the cleaning nozzle located at the center of the annularly arranged thin tubular nozzle, the cleaning solvent and the cleaning air are jetted vigorously toward the front of the paint chamber. At the same time as the inside of the paint chamber is washed, the paint is sprayed toward the nozzle holes of the narrow tubular nozzles disposed therearound, and the paint attached to the nozzle holes is reliably washed and removed in a short time. At this time, the remaining amount of paint in the paint chamber is small, and it is sufficient to clean the paint chamber of the rotary atomizing head. Therefore, paint loss during cleaning, loss of the cleaning solvent is small, and the cleaning time is shortened. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments shown in the drawings. FIG. 1 is a sectional view showing an electrostatic coating machine according to the present invention, FIG. 2 is a rear view thereof, and FIG. 3 is a flow sheet thereof.

In the drawing, reference numeral 1 denotes an air motor built in a body 2
A rotary atomizing head 5 is attached to the tip of a tubular rotary shaft 4 of 3
An electrostatic coating machine, which rotates through the inside of the rotating shaft 4.
The paint is supplied into the paint chamber 6 of the atomizing head 5.
Have been. A cleaning solvent and cleaning air are provided in the tubular rotary shaft 4.
And a cleaning nozzle Nc for supplying white, red, gray, blue, etc.
Thin tubular nozzle N for supplying frequently used color paint₁~
N ₇And select a less frequently used color paint from the color changer 7.
Capillary nozzle N to selectively supply₈But said washing
The nozzles Nc are inserted in an annular arrangement around the center.

Each nozzle Nc, N₁~ N₈The tip of the rotation
Nozzle supported in the paint chamber 6 of the atomizing head 5 in a non-contact state
Connected to the head 8 at the same time,
Is formed with an opening at the center of the nozzle hole of the cleaning nozzle Nc.
And a narrow nozzle N₁~ N₈Nose
Hole is formed. And the cleaning nozzle Nc
The cleaning solvent and the cleaning air are
Spray toward the surface side, and each formed around
Thin tubular nozzle N₁~ N ₈To the nozzle hole of
Nozzle tip 9 is attached.

The nozzle tip 9 is, for example, an inner tube 9a
And an outer tube 9b. The inner pipe 9a has an opening 1 at its tip so that the cleaning solvent and the cleaning air are injected toward the front of the paint chamber 6.
0a is formed. Further, the outer tube 9b is formed shorter than the inner tube 9a, and a flange 11 is formed on an outer peripheral portion of the inner tube 9a at a predetermined interval from the distal end opening 10b.
The cleaning solvent and the cleaning air strike the flange 11 from the tip opening 10b and are jetted toward the periphery.

At the tips of the narrow nozzles N _{1 to} N ₈ ,
A gate valve 14 including a valve seat 12 formed in a nozzle hole and a poppet 13 for closing the valve seat 12 is formed, and a wire 15 connected to the poppet 13 is connected to a valve driving unit K ₁ to K ₁ attached to the back of the body 2. It is connected to the K _8. The valve drive units K _{1 to} K ₈ are plate spring pieces S _{1 to} S ₈ for urging the wire 15 in the valve closing direction with a force greater than the paint supply pressure.
And the cylinders C ₁ -C pulling the leaf spring pieces S ₁ -S ₈ in the valve opening direction of the gate valve 14 against the urging force.
_{Consists of eight} .

The leaf spring pieces S _{1 to} S ₈ are radially extended along the back surface of the body 2, and the periphery thereof is fixed to the body 2, and the center part is formed as a cantilever having a free end. Each wire 15 is connected to its free end, and each wire 15 is pulled in the valve closing direction. The cylinders C _{1 to} C ₈ are arranged in an annular arrangement on the back side of the body 2 and contract the piston rods against the urging forces of the leaf spring pieces S _{1 to} S ₈ by air pressure or hydraulic pressure. it allows have been made to open the gate valve 14 by loosening the tension on the wire 15 by bending the leaf spring pieces S ₁ to S _8.

Reference numeral 16 denotes a cleaning manifold connected to the cleaning nozzle Nc, to which a cleaning solvent valve Vs and a cleaning air valve Va are attached. Also, M ₁
~M ₇ is a fine tubular nozzle N ₁ to N ₇ paint supply manifold connected to the through air operated regulator R ₁ to R _7, respectively, are connected to the paint supply source frequently used color A paint supply valve Vn (n = 1 to 7), a cleaning solvent valve Vs, and a cleaning air valve Va are attached.

Further, the color changing device 7 is provided with a plurality of color changing valves Vp, a cleaning solvent valve Vs, and a cleaning air valve Va for supplying a paint of a color which is rarely used, and an air operating regulator R ₈ and a coating machine cleaning. is connected to the fine tubular nozzle N ₈ through the use manifold 17. The coating machine cleaning manifold 17 is provided with a soft thinner valve Vb and a soft air valve Vc for supplying a cleaning solvent and cleaning air at a low pressure, the color changing device 7 and the remaining coating material in a coating hose 18 connecting the manifold 17. A trigger dump valve Vt to be discarded in the waste liquid tank 19 at the time of washing is attached. Further, 20 is discharge pipe for discarding residual paint in the thin tube-like nozzle N ₈ in the waste liquid tank 19, 21 is a valve for opening and closing the discharge pipe 20.

The above is an example of the configuration of the present invention, and its operation will now be described. For example, a white paint supplied in fine tubular nozzle N _1, will be described in which color change to red paint supplied in fine tubular nozzle N _2. First, when painted with white paint is a cylinder C ₁ is contracted,
When the plate spring pieces S ₁ is to loosen the wire 15 flexes forward against its resilience, so Bopetto 13 by the supply pressure of the coating material gate valve 14 away from the valve seat 12 is opened, thin tube-like white paint from the nozzle N ₁ is supplied to the paint chamber 6 is Nurigi is atomized by the rotating force of the rotary atomizing head 5 in the object to be coated (not shown).

[0019] Then, when exiting the paint by white paint is to stop the supply of compressed air to the cylinder C _1, canalicular moved poppet 13 in the valve closing direction by the repulsive force of the plate spring piece S ₁ nozzle N ₁ is closed to stop the supply of the coating material. Next, while the rotary atomizing head 5 is being rotated, the cleaning solvent valve Vs and the cleaning air valve Va of the cleaning manifold 16 are alternately opened and closed, and the cleaning solvent and the cleaning air are supplied from the cleaning nozzle Nc to the paint chamber of the rotary atomizing head 5. 6. Spray into 6.

At this time, the cleaning solvent and the cleaning air are jetted through the nozzle tip 9 at the tip of the nozzle Nc, and the cleaning solvent and the like that have passed through the inner pipe 9a flow from the tip opening 10a to the front wall of the paint chamber 6. At the same time that the inside of the paint chamber 6 is washed vigorously, a cleaning solvent or the like that has passed through the flow path of the outer tube 9b is sprayed from the distal end opening 10b onto the flange 11 toward the nozzle hole around the flange 11 and the inside of the paint chamber 6 is opened. And the white paint adhering to the gate valve 14 is removed by washing.

Since the paint only adheres to the inner wall of the paint chamber 6 and the nozzle head 8 provided with the gate valve 14, it is sufficient to clean only the adhered portion, and the loss of the white paint is extremely small. Further, since the cleaning solvent is directly sprayed on the gate valve 14 which is difficult to wash, the amount of the cleaning solvent required for cleaning is small, and the cleaning time is short. When the cleaning is finished, close the cleaning solvent valve Vs and cleaning air valve Va washing manifold 16, when the object to be coated has been reached, the gate valve 14 of the capillary-like nozzles N ₂ and the cylinder C ₂ is contracted open To supply the red paint, and paint with the next color paint.

FIG. 4 is a sectional view showing another embodiment.
Therefore, in this example, each of the nozzles Nc, N ₁~ N₈The rotating fog
The paint supply port 30 is inserted into the paint chamber 6 of the chemical head 5 in a non-contact state.
From the back side of the manifold 31
Collectively connected to the tip of the centrally located cleaning nozzle Nc
Has the same nozzle tip 9 as in the previous embodiment.
ing.

Therefore, in the present embodiment, the paint remains in the manifold 31 and the paint chamber 6 of the rotary atomizing head 5 at the end of the coating, but the nozzle attached to the tip of the cleaning nozzle Nc The chip cleans the interior of the coating chamber 6 of the rotary atomizing head 5 mainly with a cleaning solvent or the like passing through the inner pipe 9a, and mainly cleans the inside of the manifold 31 with the cleaning solvent passing through the flow path of the outer pipe 9b. Also in this case, the cleaning solvent or the like is applied to each of the narrow tubular nozzles N _{1 to} N ₈ formed around the nozzle.
Therefore, the paint adhering to each gate valve 14 can be easily washed and removed.

It should be noted that the number of the narrow nozzles N _{1 to} N ₈ is arbitrary, and the annular arrangement is not to be understood in a strict sense, as long as it is disposed around the cleaning nozzle Nc.
The gate valve 1 of the tip of the capillary-like nozzles N ₁ to N ₈
The means for opening and closing 4 is not limited to using leaf spring pieces S _{1 to} S ₈ and cylinders C _{1 to} C ₈ , but any means such as lever cylinders can be used. it may be attached directly to the rear end of the thin tube-like nozzle N ₁ to N ₈ in. Further, the rear end of the wire 15 may be connected to a magnet arranged in the narrow nozzles N _{1 to} N ₈ , and may be opened and closed by using the magnetic force from the outside. Furthermore, the gate valve 14 is not limited to the one that is closed by pulling the poppet 13 with the wire 15, and the valve seat 11 is formed inside the narrow nozzles N _{1 to} N ₈ , and the needle is pressed against the valve seat 11. A closed needle valve may be used.

[0025]

As described above, according to the present invention, each color paint is supplied directly to the paint chamber of the rotary atomizing head from the individual thin tubular nozzle inserted through the tubular rotary shaft, and the paint at the end of painting is obtained. Since the remaining paint only adheres to the inner wall of the paint chamber and the nozzle hole of the thin tubular nozzle, it is sufficient to wash only that portion. There is no need to discard the paint remaining in the hose, and there is an extremely excellent effect that the paint cost and the washing cost can be reduced by greatly reducing paint loss and washing solvent loss. In addition, since the cleaning solvent and cleaning air sprayed from the cleaning nozzle are not only sprayed to the front side but also directly to the nozzle holes of each of the narrow tubular nozzles, paint adhered to the nozzle holes that are difficult to wash can be removed. It also has the effect that it can be washed and removed in a short time.

[Brief description of the drawings]

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

FIG. 2 is a rear view thereof.

FIG. 3 is a flow sheet thereof.

FIG. 4 is a sectional view showing another electrostatic coating machine according to the present invention.

FIG. 5 is a sectional view showing a conventional electrostatic coating machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electrostatic coating machine 2 ... Body 3 ... Air motor 4 ... Tubular rotary shaft 5 ... Rotary atomizing head 6 ... Paint room 8 ... Nozzle head 9 ... Nozzle chip N ₁ to N ₈ · · · fine tubular nozzle K ₁ ~K ₈ ·
..Valve drive unit 15 ・ ・ ・ Wire 30 ・ ・ ・ Paint supply port 31 ・ ・ ・ Manifold

Continuation of front page (56) References JP-A-7-96220 (JP, A) JP-A-7-96221 (JP, A) JP-A-7-96222 (JP, A) JP-A-7-96223 (JP) , A) Japanese Utility Model 2-112353 (JP, U) Japanese Utility Model 4-91754 (JP, U) Japanese Utility Model 4-106656 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB Name) B05B 5/00-5/16 B05B 15/02

Claims (2)

(57) [Claims] 1. A rotary atomizing head (5) attached to the tip of a tubular rotary shaft (4) of an air motor (3) built in a body (2). in electrostatic coating machine for supplying paint through the axis of 4), the machine body (2 each valve drive portion provided in) (K ₁ ~K ₈₎ respectively linked wire (15) or opening and closing the nozzle hole in the needle A plurality of thin tubular nozzles (N _{1 to} N ₈ ) are inserted in a non-contact state into the shaft of the tubular rotary shaft (4), and are arranged in a circle in the paint chamber of the rotary atomizing head (5). is, the center position of the thin tube-like nozzles arranged in a ring (N ₁ to N _8), a cleaning solvent and the cleaning air with is injected toward the front side of the coating material chamber, the fine tubular nozzle which is formed around ( electrostatic coating of cleaning nozzles for jetting toward the nozzle hole of the N ₁ ~N ₈₎ (Nc) is equal to or disposed . 2. A rotary atomizing head (5) attached to the tip of a tubular rotary shaft (4) of an air motor (3) built in a body (2). in electrostatic coating machine for supplying paint through the axis of 4), the machine body (2 each valve drive portion provided in) (K ₁ ~K ₈₎ respectively linked wire (15) or opening and closing the nozzle hole in the needle to plurality of capillary-like coating nozzles (N ₁ to N ₈₎ is, the tubular rotary shaft while being inserted in the shaft (4), the paint on the paint chamber of the rotary atomizing head (5) (6) in As is collectively connected by the sequence of the circular from the back side feed opening (30) to the manifold (31) inserted through a non-contact state, the said manifold (31) in the thin tube-like nozzles arranged in a ring (N ₁ ~ the center position of the N _8), a cleaning solvent and the cleaning air with is injected toward the front side, formed around Fine tubular nozzle (N ₁ ~
Cleaning nozzle (Nc) sprayed toward the nozzle hole of N ₈ )
An electrostatic coating machine characterized by having been disposed.