JP2021006336A - Rotary atomizing coating device - Google Patents

Abstract

To form shaping air with a uniform pressure in the periphery of a bell cup without densely arranging air outlets of air for forming the shaping air in shaping airing, and to improve control accuracy of a coating pattern.SOLUTION: A shaping airing 2 jets shaping air SA from the periphery of a bell cup 1 toward an outside peripheral edge of the bell cup, and a reflection surface 1b2 on which the shaping air jetted from the shaping airing directs abuts is formed in a circumferential direction on the outside peripheral edge of the bell cup.SELECTED DRAWING: Figure 6

Description

The present invention relates to a rotary atomization coating apparatus, for example, in a two-color coating (referred to as two-tone coating), a rotary atomization coating apparatus capable of improving the control accuracy of a coating pattern and forming a uniform coating pattern. Regarding.

In the manufacturing process of an automobile, for example, when two-tone painting is applied to the surface of a car body, the paint is sprayed in the form of mist when painting with a spray gun, so the car body is masked and then painted with a spray gun. I did it and put out the border.

However, there is a problem that the work of masking the vehicle body and removing it after painting is troublesome and the work efficiency is lowered.
As a solution to such a problem, for example, in Patent Document 1 (Patent No. 5552537), a bell cup for atomizing a paint and a paint atomized by the bell cup are sprayed in a desired direction. A coating apparatus is disclosed that includes a shaping air ring that forms shaping air to allow the sprayed paint to spread out and control the coating pattern.

As shown in FIG. 7, the coating apparatus disclosed in Patent Document 1 includes a bell cup 61 whose diameter increases toward the tip (spraying direction) and shaping that rotatably accommodates the bell cup 61 around the axis P. It has an air ring 62 and a main body 63 to which the shaping air ring 62 is connected.

The main body 63 is supported by a robot arm (not shown), and is provided with a bell cup 61 and a shaping air ring 62.
An air motor 64 is built in the main body 63, a rotation shaft 65 for outputting rotation is provided in the front portion of the air motor 64, and a bell cup 61 is attached to the tip portion thereof.

The main body 63 is provided with a paint supply pipe 66 for supplying paint to the bell cup 61. Inside the bell cup 61, a paint buffer chamber 68 to which paint is supplied from the tip of the paint supply pipe 66 is formed. The paint buffer chamber 68 is formed in an annular shape so as to surround the rotation shaft 65, and the bottom portion thereof is an annular opening 68a. The tip of the paint supply pipe 66 is inserted into the opening 68a upward so that the paint supply pipe 66 does not interfere with the rotation of the bell cup 61.

Further, a plurality of paint supply holes 68b are formed in the ceiling of the paint buffer chamber 68, and the paint supplied from the paint supply pipe 66 to the paint buffer chamber 68 passes through the plurality of paint supply holes 68b and bells. It is supplied to the inner peripheral surface 61a side of the cup 61.
The paint supplied to the inner peripheral surface 61a side of the bell cup 61 is configured so that centrifugal force acts due to the high-speed rotation of the bell cup 61 to make fine particles and spray them forward.
The main body 63 is provided with a high voltage generator (not shown) so that a high voltage can be applied to the bell cup 61 (paint) to perform electrostatic coating.

Further, the main body 63 is provided with an air supply pipe 67 for supplying air to the shaping air ring 62.
The shaping air ring 62 is formed in a substantially ring shape, and is provided to form a shaping air SA around the bell cup 61 with respect to the paint sprayed from the bell cup 61 to regulate the spraying direction of the paint. ing.
As shown in the plan view of FIG. 8, the shaping air SA is ejected from a plurality of outlets 62a formed at equal intervals along the circumferential direction. As shown in FIG. 7, the ejected shaping air SA hits the outer peripheral side surface of the bell cup 61 and forms a flow along the outer peripheral surface shape toward the cup tip (outer peripheral edge portion 61A).

It should be noted that the ejection direction of the air ejected from the plurality of outlets 62a is inclined in the direction opposite to the rotation direction of the bell cup 61, and by colliding with the paint sprayed from the bell cup 61, the particles are finer. It is designed to be used.

Here, as shown in a partially enlarged view of FIG. 7, a straight portion 61A1 parallel to the direction of the axis P is formed in the outer peripheral edge portion 61A of the bell cup 61 with a predetermined width along the circumferential direction. , The shaping air SA forms a flow along the straight portion 61A1.
That is, since the straight portion 61A1 suppresses the radial spread of the shaping air SA to be smaller and the diffusion spread of the paint sprayed from the bell cup 61 is suppressed, the coating pattern is suppressed at the boundary line portion of the two-tone coating. Formation control is easy.

Japanese Patent No. 5552537

By the way, in the shaping air ring 62, as shown in the plan view of FIG. 8, in a plurality of outlets 62a arranged in the circumferential direction, a predetermined interval is provided between adjacent outlets 62a. Therefore, there is a problem that the air pressure drops near the midpoint of the adjacent outlets 62a, and shaping air SA having a uniform pressure in the circumferential direction cannot be formed. Therefore, there is a problem that the uniformity of the paint to be sprayed is impaired and the accuracy in controlling the coating pattern is lowered.

Further, in order to solve the above problem, there is also a method of making the arrangement interval of the plurality of outlets 62a arranged along the circumferential direction of the shaping air ring 62 smaller and arranging them densely, but the shaping air ring 62 There is a problem that the cost increases because the internal piping structure becomes more complicated.

The present invention has been made by paying attention to the above points, and in shaping air ring, even if air outlets for forming shaping air are not densely arranged, a uniform pressure is applied around the bell cup. It is an object of the present invention to provide a rotary atomizing coating apparatus capable of forming shaping air and improving the control accuracy of a coating pattern.

In order to solve the above-mentioned problems, the rotary atomizing coating apparatus according to the present invention includes a rotary shaft that is rotationally driven by a drive source and a bell-shaped enlarged diameter portion, and is an axial center of the enlarged diameter portion. Are arranged so as to coincide with the axis of the rotation shaft, and a bell cup that stretches and atomizes and sprays the paint on the inner peripheral surface of the enlarged diameter portion by the centrifugal force when rotating by the rotation shaft. A shaping air ring that rotatably accommodates the bell cup, ejects shaping air from around the bell cup, and guides the paint sprayed from the peripheral edge of the bell cup along the flow of the shaping air. A rotary atomization coating apparatus to which the shaping air ring is attached, a coating machine main body that supplies paint to the bell cup and air is supplied to the shaping air ring, and the shaping air ring is provided. Shaped air is ejected from the periphery of the bell cup toward the outer peripheral edge of the bell cup, and a reflective surface directly hit by the shaping air ejected from the shaping air ring surrounds the outer peripheral edge of the bell cup. It is characterized by being formed along the direction.

The reflective surface formed on the outer peripheral edge of the bell cup is formed so as to be inclined outward by 0 ° or more with respect to the axis of rotation of the bell cup with the tip of the bell cup as a base point. It is desirable to have.
Further, in the shaping air ring, the ejection angle of the shaping air ejected toward the outer peripheral edge of the bell cup is outside the axis of the rotation axis of the bell cup with the tip of the bell cup as a base point. In addition, it is desirable that it is larger than the inclination angle of the reflecting surface.

As described above, according to the present invention, the shaping air ring is formed so that the shaping air is ejected toward the outer peripheral edge of the bell cup, and the shaping air directly hits the outer peripheral edge of the bell cup. Formed a face.
As a result, the shaping air that hits the reflective surface of the bell cup generates a turbulent flow, and the shaping air forms an air flow having a uniform pressure along the circumferential direction due to the mixing action. On the other hand, the paint immediately after being atomized by the bell cup collides with the paint and is further atomized.
As a result, the atomized paint can be uniformly sprayed on the flow of shaping air. That is, the control accuracy of the coating pattern can be improved without increasing the number of outlets.

According to the present invention, shaping air having a uniform pressure is formed around the bell cup without densely arranging the air outlets for forming the shaping air in the shaping air ring, and the control accuracy of the coating pattern can be improved. It is possible to provide a rotary atomizing coating apparatus that can be improved.

FIG. 1 is a cross-sectional view showing a schematic configuration of a coating machine as a rotary atomization coating apparatus according to the present embodiment. FIG. 2 is an enlarged cross-sectional view showing a tip portion of the coating machine of FIG. FIG. 3 is a perspective view of the bell cup and shaping air ring included in the coating machine of FIG. FIG. 4 is a perspective view showing the bell cup and shaping air ring of FIG. 3 in a separated state. FIG. 5 is a partially enlarged perspective view of the inner peripheral edge of the tip of the bell cup. FIG. 6 is a partially enlarged cross-sectional view of the outer peripheral edge of the tip of the bell cup. FIG. 7 is a cross-sectional view for explaining a painting method using a conventional bell cup and shaping air ring. FIG. 8 is a plan view of a conventional shaping air ring.

Hereinafter, embodiments of the rotary atomization coating apparatus according to the present invention will be described with reference to the drawings. The rotary atomization coating apparatus according to the present embodiment is used, for example, in a coating process in an automobile production line, and sprays a paint for two-tone coating (having a boundary line with coating of another color).

FIG. 1 is a sectional view showing a schematic configuration of a coating machine 100 as a rotary atomizing coating apparatus according to the present embodiment, and FIG. 2 is a sectional view showing an enlarged tip portion of the coating machine 100 of FIG. Is. This painting machine 100 is used by being attached to the tip of an arm of a painting robot, for example, in a painting line in a car manufacturing factory.

The coating machine 100 shown in FIGS. 1 and 2 is a device for spraying paint onto an object to be coated. The coating machine 100 includes a coating machine main body 3, a shaping air ring 2 connected to the coating machine main body 3, and a bell cup 1 rotatably housed in the shaping air ring 2.

The coating machine main body 3 is supported by a robot arm (not shown) for displacing the coating machine 100 at a desired position and posture, and a portion to which a bell cup 1 and a shaping air ring 2 are attached as described above. The air motor 3a is built in. From the front surface of the air motor 3a, a rotation shaft 3b that outputs rotation is projected forward. A bell cup 1 is attached to the tip of the rotating shaft 3b, and the bell cup 1 is configured to rotate at high speed around the rotating shaft 3b by driving the air motor 3a.

Further, paint is supplied to the coating machine main body 3 from a paint supplying means (not shown), and a feed tube (not shown) provided along the center of the shaft for supplying the paint to the bell cup 1 and a shaping air ring. An air supply pipe 3d for supplying air to 2 and a high voltage generator 3e for applying a high voltage to the paint are built-in.
The high voltage generated by the high voltage generator 3e is supplied to the bell cup 1 through the case of the air motor 3a. Then, an electric field is generated between the bell cup 1 to which a high voltage is applied and the object to be coated (work).

Here, the configurations of the bell cup 1 and the shaping air ring 2 will be described in detail. FIG. 3 is a perspective view of the bell cup 1 and the shaping air ring 2 included in the coating machine 100, and FIG. 4 is a perspective view of the bell cup 1 and the shaping air ring 2 of FIG. 3 in a separated state.

The shaping air ring 2 is a member for ejecting shaping air SA for regulating the spraying direction of the paint sprayed from the bell cup 1. That is, the paint sprayed from the peripheral edge of the bell cup 1 is guided along the flow of the shaping air SA to regulate the spraying direction and facilitate the formation of a desired coating pattern.

As shown in FIG. 4, the shaping air ring 2 is formed in a ring shape, and an opening 2b for rotatably accommodating the bell cup 1 is formed in the center, and as shown in FIG. 2, in the direction of spraying the paint. On the other hand, at the rear of the bell cup 1, it is attached to the coating machine main body 3 in a state where the axis thereof coincides with the axis P of the bell cup 1.

Further, as shown in FIG. 1, air having a predetermined pressure is supplied from the pressure air source to the air supply pipe 3d of the shaping air ring 2 via the valve 4. As shown in FIGS. 3 and 4, a large number of outlets 2a are arranged in a circular shape on the shaping air ring 2 so as to surround the bell cup 1, and the shaping air ring 2 is supplied to the air supply pipe 3d shown in FIG. The shaped air SA is formed by blowing out the generated air from the outlet 2a. The shaping air SA controls the spraying direction of the paint sprayed from the bell cup 1.
In the present embodiment, each shaping air SA from the plurality of outlets 2a is configured to be ejected toward the outer peripheral edge of the bell cup 1.

As shown in FIG. 4, the bell cup 1 has a straight body portion 1a having a constant outer diameter and a diameter-expanded portion 1b whose diameter is expanded in a bell shape from the straight body portion 1a. The straight body portion 1a is formed in a tubular shape as shown in FIGS. 1 and 2, and a rotating shaft 3b projecting from the air motor 3a is inserted into the inner surface 1a1 side thereof, and the tip portion of the rotating shaft 3b is inserted. , It is adapted to fit into the through hole 1c1 formed in the center of the partition plate 1c that separates the straight body portion 1a and the enlarged diameter portion 1b.
As a result, the axis of the bell cup 1 is aligned with the axis P of the rotating shaft 3b, and the bell cup 1 is rotatably supported by the rotating shaft 3b at the frontmost portion in the spray direction of the paint.

Further, in the bell-shaped enlarged diameter portion 1b, a feed tube (shown) provided along the axial center of the coating machine main body 3 on the rear end side (partition plate 1c side) of the inner peripheral surface 1b1 thereof. A paint supply hole (not shown) for supplying the paint from the cup to the inside of the cup is formed. Further, a disk-shaped hub (not shown) formed of resin is detachably attached to the rear end side of the inner peripheral surface 1b1, and a large number of hubs formed around the hub are detachably attached. The paint flowing out from the paint outflow hole is supplied to the inner peripheral surface 1b1 of the bell cup 1.
Further, in the diameter-expanded portion 1b, the inner peripheral surface 1b1 thereof is tapered toward the tip side, and has a predetermined angle (for example, 29 °) with respect to the axis P (the axis of the rotating shaft 3b). ) It is tilted. As a result, when the bell cup 1 rotates around the axis P, the paint supplied from the paint supply hole is thinly stretched on the inner peripheral surface of the cup toward the peripheral portion of the cup.

Further, as shown in FIG. 5 with a partially enlarged perspective view of the inner peripheral edge portion of the tip of the bell cup, a plurality of groove portions 10 for atomizing the paint are formed on the peripheral edge portion of the tip of the inner peripheral surface 1b1 in the circumferential direction. The groove portions 10 are formed in a slope shape in the diameter-expanding direction toward the tip of the cup. By these groove portions 10, the paint thinly stretched on the inner peripheral surface 1b1 is atomized and atomized.

Further, as shown in FIG. 6 which is a partially enlarged cross-sectional view of the outer peripheral edge of the tip of the bell cup 1, the reflecting surface 1b2 of the shaping air SA is formed on the outer peripheral edge of the tip of the bell cup 1.
The reflecting surface 1b2 is formed so that the shaping air SA injected from the shaping air ring 2 directly hits the reflecting surface 1b2. Therefore, the reflecting surface 1b2 is inclined outward by a predetermined angle θ1 with respect to the axial center P of the bell cup 1 with the tip of the bell cup 1 as a base point. It is desirable that the angle θ1 is 0 ° or more. This is because if θ1 is less than 0 °, the shaping air SA does not directly hit the reflecting surface 1b2.

Further, in order to directly hit the reflecting surface 1b2 of the bell cup 1 with the shaping air SA, the shaping air SA ejected from the outlet 2a of the shaping air ring 2 as described above is the outer peripheral edge of the bell cup 1. It is ejected toward.
Specifically, the ejection angle θ2 of the shaving air SA is larger than the inclination angle θ1 of the reflecting surface 1b2 outward with respect to the axial center P of the bell cup 1 with the tip of the bell cup 1 as a base point. Has been made.

As a result, the shaping air SA that hits the reflecting surface 1b2 generates a turbulent flow T near the reflecting surface 1b2, and due to the mixing action, the shaping air SA has a uniform pressure along the circumferential direction near the peripheral edge of the bell cup 1. It becomes. Immediately after being atomized in the bell cup 1, the paint collides with the paint, and the paint is further atomized and sprayed forward along with the flow of shaping air SA. The spray range of the sprayed paint is regulated by shaping air SA having a uniform pressure in the circumferential direction.

In the coating machine 100 configured in this way, a high voltage is applied to the bell cup 1 by the high voltage generator 3e in the coating machine main body 3. Further, the air motor 3a is driven, and the rotation of the rotation shaft 3b causes the bell cup 1 to rotate in a predetermined direction at a predetermined rotation speed (for example, 25,000 rpm).
Further, a state in which high-pressure air is supplied to the air supply pipe 3d of the coating machine 100, and the shaping air SA is ejected from the outlet 2a of the shaping air ring 2 toward the outer outer peripheral edge of the bell cup 1 at a predetermined flow rate. Will be done.

Here, the shaping air SA injected from the shaping air ring 2 directly hits the reflecting surface 1b2 formed on the outer peripheral edge of the bell cup 1.
Then, the shaping air SA that hits the reflecting surface 1b2 generates a turbulent flow T in the vicinity of the reflecting surface 1b2. Due to the mixing action of the turbulent flow T, the pressure of the shaping air SA becomes uniform along the circumferential direction of the tip of the bell cup 1.

On the other hand, the coating machine 100 supported by the robot arm (not shown) is moved so as to be close to the coating surface (not shown), and the bell cup 1 is arranged in a predetermined posture with respect to the coating surface.

Further, the paint supplied from the paint supply pipe of the coating machine main body 3 is stretched toward the cup tip (peripheral portion) on the inner peripheral surface 1b1 of the rotating bell cup 1 and atomized by the plurality of groove portions 10. Sprayed forward.
Here, an air flow having a uniform pressure is formed in the vicinity of the outer peripheral edge of the tip of the bell cup 1, and the paint immediately after being atomized from the bell cup 1 collides with the air flow. .. As a result, the paint is further atomized and sprayed uniformly forward along the flow of shaping air SA.

As described above, according to the embodiment of the present invention, the shaping air ring 2 is formed so that the shaping air SA is injected toward the outer peripheral edge portion of the bell cup 1, and the outer peripheral edge portion of the bell cup 1 is formed. A reflective surface 1b2 to which the shaping air SA directly hits was formed.
As a result, the shaping air SA that hits the reflecting surface 1b2 of the bell cup 1 generates a turbulent flow T, and the shaping air SA forms an air flow having a uniform pressure along the circumferential direction due to the mixing action thereof. On the other hand, the paint immediately after being atomized by the bell cup 1 collides with the paint and is further atomized.
As a result, the atomized paint can be uniformly sprayed on the flow of shaping air SA. That is, the control accuracy of the coating pattern can be improved without increasing the number of outlets 2a.

The rotary atomization coating apparatus according to the present invention will be further described based on examples. In this example, the following experiments were performed based on the above-described embodiment.
In Examples 1 to 9, a reflective surface is formed on the outer peripheral edge of the bell cup as shown in FIG. 6 of the present embodiment, the inclination angle of the reflective surface with respect to the center of the rotation axis, and the shaping with respect to the center of the rotation axis of the bell cup. Spraying was performed on the painted surface on the condition of the air ejection angle (the film thickness standard to be formed was 15 μm or more and less than 20 μm).

Table 1 shows the conditions and results of Examples 1 to 9.
Under the conditions shown in Table 1, the air reflecting surface inclination angle indicates an angle at which the tip of the bell cup is used as a base point and is inclined outward with respect to the center of the rotation axis of the bell cup. Further, the air ejection direction angle indicates an angle in which the tip of the bell cup is used as a base point and is inclined outward with respect to the center of the rotation axis of the bell cup.
Further, in the results shown in Table 1, ◯ indicates that the atomization was good and uniform coating was possible, and × indicates that the atomization was poor and uniform coating was not possible.

As shown in Examples 6 and 9, when the reflection surface angle was 0 ° or more and the ejection angle of the shaping air was larger than the reflection surface angle, the particles were sufficiently atomized and uniformly applied.

As a result of the above, a turbulent flow is generated by forming a reflective surface on the outer peripheral edge of the bell cup as in the embodiment in which the shaping air directly hits, and the air pressure in the circumferential direction is made uniform by the mixing action. It was confirmed that the paint could be further atomized and the paint to be sprayed could be made uniform.

1 Bell cup 1a Straight body 1b Expanded diameter 1b2 Reflective surface 2 Shaping air ring 3 Coating machine body 3a Air motor (drive source)
10 Groove 100 Rotating atomizing coating device SA shaping air

Claims (3)

A rotating shaft that is driven to rotate by a drive source,
A bell-shaped enlarged diameter portion is provided, and the axis of the enlarged diameter portion is arranged so as to coincide with the axial center of the rotating shaft, and the enlarged diameter portion is generated by centrifugal force when rotating by the rotating shaft. A bell cup that stretches and atomizes the paint on the inner peripheral surface of the
A shaping air ring that rotatably accommodates the bell cup, ejects shaping air from the periphery of the bell cup, and guides the paint sprayed from the peripheral edge of the bell cup along the flow of the shaping air.
A coating machine body to which the shaping air ring is attached, which supplies paint to the bell cup and also supplies air to the shaping air ring,
It is a rotary atomization coating device equipped with
The shaping air ring ejects shaping air from the periphery of the bell cup toward the outer peripheral edge of the bell cup.
A rotary atomization coating apparatus characterized in that a reflecting surface directly hit by shaping air ejected from the shaping air ring is formed on the outer peripheral edge of the bell cup along the circumferential direction. The reflective surface formed on the outer peripheral edge of the bell cup
The rotary atomization according to claim 1, wherein the bell cup is formed so as to be inclined outward by 0 ° or more with respect to the axis of rotation of the bell cup with the tip of the bell cup as a base point. Painting equipment. In the shaping air ring
The ejection angle of the shaping air ejected toward the outer peripheral edge of the bell cup is
The rotary atomization coating apparatus according to claim 2, wherein the tip of the bell cup is used as a base point and is larger than the inclination angle of the reflective surface on the outside with respect to the axis of rotation of the bell cup. ..

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