JP3131717B2 - Painting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for painting a work having a mainly irregular cross-sectional shape, such as a door sash of an automobile.

[0002]

2. Description of the Related Art In order to paint a work as described above, it is necessary to sufficiently reach and adhere the paint to a portion that is difficult to paint, such as an inner peripheral surface of a concave portion formed on the surface of the work. In such a case, for example, Japanese Utility Model Laid-Open No. 63-69
No. 580, using a ring-shaped coating gun having a plurality of nozzles arranged radially toward the center, paint is simultaneously sprayed from the periphery of the work, and the paint sprayed from each nozzle near the work is sprayed. If they interfere with each other, the flight direction of the paint near the work becomes random, so that the paint can be applied to the above-mentioned difficult-to-paint portion, and the work surface can be painted uniformly.

In order to make the paint sprayed from each nozzle interfere more effectively, the paint sprayed from the nozzle is atomized by air sprayed from the vicinity of the nozzle.
A so-called air atomization type nozzle may be used, and the atomized paint reaches the workpiece together with the atomizing air, and the air interference is added compared to the case where only the paint is sprayed. Paint can be applied to every detail.

[0004]

In the above-mentioned conventional coating method, there is no problem when the entire surface of the work is coated.
For example, when painting only half of the work surface,
It is necessary to stop the operation of the nozzle facing the unpainted part. However, when the operation of some nozzles is stopped in this way, the mist paint may sneak around and adhere to unpainted parts, and the direction in which the paint splatters from the paint gun will stop operating the nozzles. Therefore, there is a possibility that the paint may be scattered on the unnecessary parts other than the work.

In view of the above problems, the present invention has been made in consideration of the above problems, and when the coating is performed using an annular coating gun having an air atomizing type nozzle, even if the operation of some nozzles is stopped, the work surface It is an object of the present invention to provide a coating method in which the paint does not flow into a portion facing the nozzle whose operation has been stopped, and the scattering direction of the paint from the coating gun does not change.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for disposing a work near the center of an annular coating gun having a plurality of nozzles radially arranged toward the center. In a coating method for individually controlling the injection of paint from each nozzle according to a coating portion, each of the nozzles is an air atomization type for atomizing paint by air injected from the vicinity of the nozzle, and the work It is characterized in that the injection of the atomizing air is continued even when the injection of the paint from any of the nozzles is stopped according to the painted portion.

[0007]

When stopping the operation of some of the nozzles, the atomizing air is continuously sprayed even if the spraying of the paint is stopped. As a result, the atomizing air is continuously blown to the part of the work surface facing the nozzle where the paint is not sprayed, so that even if the paint sprayed from another nozzle tries to flow around, the atomizing air is sprayed. The paint does not adhere to parts that do not require painting because they are pushed back by the air.

[0008] Further, the atomized paint scatters on the atomizing air, but the direction of the air blown out from the coating gun does not change unless the spraying state of the atomizing air changes.
The paint scattering direction does not change.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 1 denotes a ring-shaped coating gun used for carrying out the present invention, which surrounds a work W having an irregular cross-sectional shape such as a door sash of an automobile. And is attached via a joint block 41 to the tip of an arm 4 of a painting robot (not shown). The coating gun 1 is formed by joining annular blocks 2 and 3 partially provided with notches 11 for allowing a workpiece W to enter and exit therein so that their central axes coincide with each other. A gasket 30 is sandwiched between the two and three joining surfaces. Along the circumferential direction, a paint supply path 22 and an atomizing air supply path 23 are engraved on the joint surface on the block 2 side, and an exhaust passage 32 is engraved on the joint surface on the block 3 side. 22 ・ 23 ・ 32 is gasket 3
0 to form a mutually independent passage,
Each independent passage 22a provided in the arm 4
23a and 32a.

[0010] By the way, paint is applied to the work W on the block 2.
Nozzles 21 are arranged radially at regular intervals. The nozzle 21 is a so-called air atomization type nozzle that sprays air from around the nozzle 21 onto the paint sprayed from the nozzle 21 to form a mist, and sprays paint mist onto the work W together with the atomizing air. The paint was sprayed to spread the paint even to the recessed portion of the surface of the work W so that uniform painting could be performed.

As shown in FIG. 2, the nozzle 21 communicates with a paint supply passage 22 via a passage 22b. A cover plate 24 containing the nozzle 21 is attached to each nozzle 21, a flange 21 a is provided around the nozzle 21, and the nozzle 21 is set in the cover plate 24, whereby the buffer chamber is placed in the cover plate 24. 25 was formed. The buffer chamber 25 communicates with the atomizing air supply passage 23 through a passage 23 b formed in the block 2.
The atomizing air supplied from 3 passes through a hole 21b penetrated by the flange 21a, reaches the buffer chamber 25, is further sprayed from an air nozzle 24a provided through the cover plate 24, and sprays the paint sprayed from the nozzle 21. It was made to be. Since the paint atomized in this way is uniformly dispersed in each direction and is sprayed in a circular area, the paint is sprayed from the air port 24b toward the atomized paint so that the paint is sprayed in a range of a desired shape. Air is sprayed, and the spray pattern of the paint is adjusted so that the paint is sprayed in, for example, an elliptical range.

By the way, in block 3, the block 3
Needle valve 3 which is opened and closed by a cylinder 34 formed in
3 are buried. The needle valve 33 is normally urged in a closing direction by a spring 35 in a cylinder 34 to close the gap between the paint supply passage 22 and the passage 22b, thereby restricting the ejection of the paint from the nozzle 21. When compressed air, which is a working fluid, is supplied into the cylinder chamber 34 through the passage 31, the needle valve 33 retreats due to the pressure of the compressed air, thereby opening the passage 22 b to the paint supply passage 22. Then, the paint is sprayed from the nozzle 21. By the way, a band-shaped block 5 is fitted on the outer periphery of the block 3, and cylinders provided with air pressure supply passages 51 to 56 respectively provided on the inner peripheral surface of the block 5 for each nozzle 21. 34 are individually and independently communicated with each other via the passage 31. In addition, these air pressure supply paths 51 to 5
Numerals 6 are connected to the respective passages 51a to 56a in the arm 4 via the manifold block 41, and are configured to receive the supply of compressed air individually and independently. Therefore, when the compressed air is supplied to all or any of the air pressure supply paths 51 to 56 in a state where the paint is supplied to the paint supply path 22, the needle connected to the ventilation pressure supply path to which the compressed air is supplied is supplied. The valve 33 is retracted, and the paint is injected only from the nozzle 21 corresponding to the retracted needle valve 33.
The blocks 2 and 3 are mutually fastened by bolts 37, and the blocks 3 and 5 are mutually fastened by bolts 57. 32a is the needle valve 3
3 is a passage through which the back chamber 36 is evacuated when retracted, and communicates with the exhaust passage 32.

In the present embodiment, the direction of spraying the paint from the nozzle 21 is inclined at a predetermined angle θ (for example, approximately 30 degrees). By inclining the paint spraying direction by the predetermined angle θ in this manner, the air containing the mist paint becomes easier to flow in the groove-shaped concave portion of the work, and is more uniform than when the paint is sprayed from the direction perpendicular to the work surface. Paint can be forcibly maintained in one direction, and the paint spraying direction from the paint gun 1 can be forcibly maintained in one direction. Also, the paint gun itself can be prevented from being stained by the paint, and the distance between the work and the nozzle can be reduced. And the coating gun can be further miniaturized.

According to the above configuration, for example, when the entire outer peripheral surface of the work W is being coated, when switching is performed so that only the area Wa is coated, the nozzle facing the uncoated surface, that is, the right side in FIG. Three nozzles 2 located at
Therefore, the supply of compressed air to the air pressure supply passages 51 to 53 must be stopped. Thus, the injection of the paint from the nozzle 21 located on the right side is stopped. However, the atomizing air applied to the nozzles 21 whose operation has been stopped continues to be jetted. Therefore, the paint sprayed from the nozzle 21 located on the left side is pushed back by the air sprayed from the vicinity of the nozzle 21 on the right side even if the paint sprayed from the vicinity of the nozzle 21 on the right side attempts to go around the unnecessary area beyond the area Wa. The paint scattering direction does not change.

[0015]

As is apparent from the above description, according to the present invention, when coating is performed using an annular coating gun having an air atomizing type nozzle, only a part of the work surface is coated. However, even when painting, the paint does not flow around unpainted parts, and the direction of paint splash from the paint gun is constant regardless of the increase or decrease of the painted part on the work surface. It is possible to prevent the paint from being accidentally scattered to other parts than the above.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II.

[Fig. 3] III-III sectional view

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paint gun 2 block 3 block 5 block 21 nozzle 22 paint supply path 23 atomization air supply path 33 needle valve 24a air nozzle (of atomization air)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B05D 1/00-7/26

Claims (1)

(57) [Claims] 1. A work is arranged near the center of an annular coating gun having a plurality of nozzles radially arranged toward the center, and the spray of paint from each nozzle is individually performed in accordance with a coated portion of the work. In the controlling coating method, each of the nozzles is an air atomization type in which the paint is atomized by air injected from the vicinity of the nozzle, and the paint is sprayed from any of the nozzles in accordance with a coating portion of the work. A spraying method characterized in that spraying of atomizing air is continued even when stopping.