JP4672872B2 - Non-electrostatic rotary coating equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-electrostatic rotary coating apparatus that is suitable for thin coating of a coating film, and particularly capable of suitably coating the inner peripheral surface of an elongated hole.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a coating apparatus that applies a paint using a rotational force without using hydraulic pressure or air pressure, there is an electrostatic coating apparatus that applies static electricity to a rotating body such as a cup shape.
[0003]
[Problems to be solved by the invention]
However, such an electrostatic coating apparatus has a problem that if the thickness of the coating film is reduced, the supply of the coating becomes unstable and coating unevenness is likely to occur.
[0004]
[Means, actions and effects for solving the problems]
As a means for solving such a problem, the non-electrostatic rotary coating apparatus according to the first aspect of the present invention is such that the paint supplied from the upper end flows down along the inner peripheral surface by gravity and centrifugal force. A paint supply pipe having an open lower end arranged in a vertical or inclined posture, a circular edge at the lower end of the outer peripheral surface formed by tapering the inner peripheral surface to the outer peripheral surface of the lower end of the paint supply pipe, and the paint supply pipe Ri Do a drive device for rotation about the central axis, the ratio D / d between the outer diameter d of the diameter D and the paint supply tube edge a to shall and characterized in that it is a 1, gravity The paint flowing down as a thin film on the inner surface of the paint supply pipe due to the centrifugal force is discharged from the circular edge at the lower end of the paint supply pipe in the radial direction by the centrifugal force, and is atomized by collision with air and coated. It can be applied to objects, and a certain amount of paint can be supplied. Since that, thin coating, and can perform coating with a uniform thickness, in particular, it is suitable for coating the inner circumferential surface of the hole.
In addition, since the ratio D / d between the diameter D of the edge and the outer diameter d of the paint supply pipe is 1, the lower end of the paint supply pipe is tapered from the inner peripheral surface, and the lower end of the outer peripheral surface is cut. The edge is formed, the structure is simple, and the inner peripheral surface of the extremely small-diameter hole can be coated.
[0007]
In the invention of claim 2 , since the ratio L / D of the distance L from the center of the bearing at the lowest end of the paint supply pipe to the center of the edge is 1 to 20, it is possible to paint the inner peripheral surface of the elongated hole. Suitable.
[0008]
A third aspect of the present invention, a L / D is 5-15, bending from a relatively high rigidity, can be suppressed relatively small deflection of the edge by a dynamic unbalance.
[0009]
In the invention of claim 4 , since the coating is applied in the vicinity of the edge with a material having a low affinity for the paint, the paint is repelled from the outer periphery of the edge, so that it accumulates on the outer periphery of the edge and is discharged intermittently, resulting in uneven coating. Is prevented from occurring.
[0010]
According to the invention of claim 5 , an outer cylinder is arranged concentrically with a small gap in a portion excluding a portion close to the edge of the paint supply pipe, and an air flow from between the outer cylinder and the paint supply pipe flows toward the tip. When painting a blind hole, when the edge approaches the abutting surface, the air is allowed to flow forward against the centrifugal force to paint the abutting surface. In addition, by constantly flowing air, the outer peripheral surface and flat surface of the article can be uniformly coated with a relatively narrow width and a thin film thickness.
[0011]
According to the sixth aspect of the present invention, since the recess is formed in the outer periphery of the lower end of the paint supply pipe and the angle of the edge is sharpened, the atomization of the paint can be promoted.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In FIG. 1, reference numeral 1 denotes a three-way switching valve that allows the paint inflow pipe 2 and the cleaning liquid inflow pipe 3 to communicate with the discharge pipe 4 alternately.
[0013]
The paint inflow pipe 2 is provided with a throttle valve (not shown) so that the flow rate can be adjusted.
[0014]
Reference numeral 5 denotes a drive device main body, and a paint supply pipe 6 is vertically supported by two upper and lower bearings 8 at the center thereof.
[0015]
A sharp edge 7 is formed at the lower end of the paint supply pipe 6 by providing an inclined surface 15 of approximately 45 ° on the inner surface.
[0016]
The rotor 10 of the air turbine 9 is fixed to the upper end of the paint supply pipe 6, and the air ejected from the jet nozzle 11 hits the blades of the rotor 10 and then is discharged from the exhaust port 12 to be fixed to the rotor 10. The paint supply pipe 6 rotates at a high speed.
[0017]
A cover 13 is fixed to the upper surface of the drive device body 5, and a pipe 14 fixed downward to the cover 13 is fitted in the center hole of the paint supply pipe 6 tightly and relatively freely rotatably. This pipe 14 communicates with the discharge pipe 4 of the three-way switching valve 1.
[0018]
In this embodiment, in order to coat the inner peripheral surface of the hollow body a, the paint supply pipe 6 is rotated by the air turbine 9 and the paint inflow pipe 2 of the three-way switching valve 1 is connected to the discharge pipe 4. When communicating, the paint flows down as a thin film on the inner surface of the paint supply pipe 6 due to gravity and centrifugal force. When reaching the lower end, the paint spreads on the slope 15 and is then discharged radially from the edge 7 to collide with air. And is applied to the inner peripheral surface of the hollow body a. By moving the hollow body a at a constant speed in the axial direction, a uniform coating film is formed on the inner peripheral surface.
[0019]
When the object to be coated is heavy, the coating apparatus may be moved.
[0020]
After coating is completed or when the color is changed, the interior is cleaned by supplying a cleaning liquid to the coating apparatus by switching the three-way switching valve 1.
[0021]
In the present embodiment, as shown in FIG. 2, a recess 16 is formed on the outer periphery of the lower end of the paint supply pipe 6 to sharpen the angle of the edge 7, thereby facilitating the atomization of the paint. .
[0022]
In addition, by coating the outer peripheral surface near the tip of the coating material supply pipe 6 with a material such as Teflon (registered trademark) having a low affinity for the coating material, the coating material is repelled from the outer periphery of the edge 7 so that the coating material becomes the edge. 7 is prevented from being unevenly generated after being accumulated on the outer periphery of 7.
[0023]
Further, as shown in FIG. 3, an outer cylinder 17 is arranged concentrically with a small gap in a portion excluding the vicinity of the edge 7 of the paint supply pipe 6, and between the outer cylinder 17 and the paint supply pipe 6 to the tip. Flowing air in a timely manner and flowing air when the edge 7 approaches the abutting surface c of the blind hole b, thereby causing the paint to flow forward against the centrifugal force and coating the abutting surface c. can do.
[0024]
In addition, it is possible to paint the outer peripheral surface and the flat surface of the article by constantly flowing the air, and it is particularly suitable for painting the flat plate into a strip with a constant width, and the coating film is thin and has a uniform thickness. Can be applied.
[0025]
In the present embodiment, as shown in FIG. 1, since the diameter D of the edge 7 and the outer diameter d of the paint supply pipe 6 are the same, that is, D / d is 1, the diameter into which the paint supply pipe 6 can be inserted. Can be applied to the inner peripheral surface of the hole slightly larger than d, but by increasing the D by forming a large diameter portion at the lower end of the paint supply pipe 6, the centrifugal force can be increased even at the same rotational speed. The atomization of the paint can be promoted.
[0026]
However, if D / d exceeds 3, not only is it difficult to paint small-diameter holes, but dynamic unbalance is likely to occur, so D / d is preferably 0.8 to 3.0.
[0027]
On the other hand, if the ratio L / D between the distance L from the center of the bearing 8 at the lowest end of the paint supply pipe 6 to the center of the edge 7 and the diameter D of the edge 7 is too small, it becomes impossible to paint a long hole. If it is too large, dynamic imbalance tends to occur, so 1 to 20 is preferable, and 5 to 15 is more preferable.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view of an embodiment of a non-electrostatic rotary coating apparatus of the present invention.
FIG. 2 is an enlarged sectional view of a lower end portion of another embodiment of the paint supply pipe.
FIG. 3 is an enlarged cross-sectional view of a lower end portion according to another embodiment of the present invention.
[Explanation of symbols]
6: Paint supply pipe 7: Edge 9: Air turbine (drive device)
15: Slope 17: Outer cylinder

Claims (6)

A paint supply pipe arranged lower opening in a vertical or inclined position as the paint supplied from the upper end flows down along the inner peripheral surface by gravity and centrifugal force, from the inner circumferential surface of the lower end of the paint supply tube a circular edge of the outer peripheral surface lower end formed denoted by the tapered toward the outer peripheral surface, Ri Do a drive device for rotating the paint supply pipe around the central axis,
Non-electrostatic rotary coating apparatus you and the ratio D / d between the outer diameter d of the paint supply pipe to the diameter D of the edge is one. 2. The non-electrostatic rotation according to claim 1, wherein a ratio L / D between a distance L from a center of a bearing at a lowermost end of the paint supply pipe to a center of the edge and the D is 1 to 20. Painting equipment.   The non-electrostatic rotary coating apparatus according to claim 2, wherein the L / D is 5 to 15. Non-electrostatic rotary coating apparatus according to claim 1, 2 or 3, characterized in that the coated material having a small affinity for paint around the edges. The outer cylinder is arranged concentrically with a small gap in the paint supply pipe except for the part close to the edge, and the air flow from between the outer cylinder and the paint supply pipe flows toward the tip. The non-electrostatic rotary coating apparatus according to claim 1, 2, 3, or 4 . The outer periphery of the lower end of the paint supply tube, to form a recess, non-electrostatic rotary coating apparatus according to claim 1, 2, 3, 4 or 5, characterized in that the sharp angle of the edge.

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