JP5342600B2 - Rotary atomization coating equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary atomizing coating device in which the generation of a negative pressure in front of a rotary atomizing head is suppressed and good atomization of a coating material can be obtained. <P>SOLUTION: In the rotary atomizing coating device P having the rotary atomizing head 3 for straying the coating material forward and radially outward and forming the coating pattern by spraying shaping air from a plurality of shaping air discharging holes 13 arranged around the back of the rotary atomizing head 3 to the vicinity of the front end fringe of the rotary atomizing head 3, the shaping air is discharged as a helical flow S from each of the shaping air discharging holes 13. A manifold 7 communicating to a shaping air supplying channel 8, a helical flow forming chamber 9 communicating with the manifold 7 via inclined supplying holes 12 and generating the helical flow S by air flowing in from the inclining supplying holes 12 colliding to the inner peripheral surface of the same, and the shaping air discharging hole 13 communicating with each of the helical flow forming chamber 9 are formed in a shaping ring 5. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  The present invention relates to a rotary atomizing coating apparatus.

  As an example of the rotary coating apparatus, a rotary atomizing head (bell cup) provided rotatably at the tip of the main body of the coating machine can be cited. The paint supplied into the rotary atomizing head from the paint supply pipe spreads in a thin film on the inner surface of the rotary atomizing head due to the centrifugal force generated by the high speed rotation of the rotary atomizing head, and the high voltage disposed in the rotary coating device. A high voltage is applied by the cable. The coating material is changed from a thin film shape to fine particles by the centrifugal force and discharged from the coating discharge end at the tip of the rotary atomizing head, and the atomized coating material is charged by the applied high voltage, so that the particles They repel each other and the atomization of the paint is further promoted. The atomized paint is applied with a force that scatters in the radial direction due to the centrifugal force. However, the paint is sprayed from the shaping air outlet of the coating machine body so that the paint is scattered in front of the rotary atomizing head. In this way, a paint pattern is formed. The paint is further atomized by collision with shaping air.

  However, since a negative pressure is generated in front of the rotary atomizing head as the amount of the shaping air or the flow velocity increases, the shaping air is attracted in the direction of the rotational axis of the rotary atomizing head by this negative pressure, and the paint Insufficient atomization is likely to cause paint sagging after application to the workpiece.

  In order to solve such a problem, the shaping air is made to flow in a spiral path by inclining the shaping air outlet in the direction opposite to the rotation direction of the rotary atomizing head, and the centrifugal force generated by the spiral path causes the negative pressure to flow. A technique is known that suppresses the convergence of the paint fine particles in the direction of the rotational axis of the rotary atomizing head and promotes the atomization of the paint by setting so as to overcome the suction force based on 1 and 2).

  Further, Patent Document 3 discloses a configuration in which assist air is blown out to narrow a coating pattern width when painting a lattice part or a molding part of a bumper to cope with a complicated shape such as a bumper. ing.

Japanese Patent Laid-Open No. 7-24367 JP-A-8-229445 JP-A-10-71363

  With the techniques described in Patent Documents 1 and 2, in which the shaping air jetting port is inclined in the direction opposite to the rotation direction of the rotary atomizing head, the coating pattern cannot be narrowed even if the amount of shaping air or the flow velocity is increased. Therefore, for example, when a narrow and deep recess is formed in a workpiece having a complicated shape such as a bumper, a sufficient amount of atomized paint can be applied to the bottom of the recess in a short time (a predetermined cycle time). It will be difficult to reach. In such a case, conventionally, measures have been taken such as an operator performing supplementary work separately with a hand gun in a later process.

  In particular, recent bumpers often employ narrower and deeper recesses in order to improve design. In order to reach a sufficient amount of atomized paint to the bottom surface of such a recess, it is necessary to increase the amount or flow velocity of shaping air. However, if the amount or flow velocity of shaping air is increased, rotational atomization Since the negative pressure generated in front of the head is also increased, the shaping air is attracted in the direction of the rotational axis of the rotary atomizing head, and the atomization of the paint is insufficient, and the paint sagging easily occurs on the workpiece. This problem is difficult to cope with even the technique described in Patent Document 3.

  The present invention was created in order to solve the above-described problems, and a rotary atomizing coating apparatus capable of suppressing the generation of negative pressure in front of the rotary atomizing head and obtaining good atomization of the paint. The purpose is to provide.

In order to solve the above-mentioned problems, the present invention comprises a rotary atomizing head that sprays paint in a forward and radially outward direction, and a rotary atomizing head from a plurality of shaping air ejection holes arranged around the rear of the rotary atomizing head. In a rotary atomizing coating apparatus that forms a paint coating pattern by ejecting shaping air toward the vicinity of the front edge of the apparatus main body in which a shaping air supply path is formed, and a shaping ring attached to the front end of the apparatus main body, The shaping ring is formed in an annular shape around the axis of the rotary atomizing head, a manifold communicating with the shaping air supply path, and a plurality of the shaping rings are arranged around the axis in front of the manifold, Communicating with the manifold through the inclined supply holes, and the air flowing from the inclined supply holes collides with the inner peripheral surface, generating a spiral flow. A spiral flow forming chamber that has, said shaping air outlet holes communicating with the respective spiral flow forming chamber, said shaping air from each of the respective shaping air outlet holes, characterized in that the ejected as helical flow.

  Since the spiral flow has a swirl component, it has high straightness. In addition, a large negative pressure is hardly generated in front of the rotary atomizing head by this spiral flow. Even if the amount or flow velocity of the shaping air is increased, the spiral flow itself acts so as to be restrained from spreading in the radial direction, so that the rotational atomizing head increases with the increase in the amount or flow velocity of the shaping air. There is no problem that the negative pressure generated in front of is increased. Therefore, the inconvenience that the shaping air is attracted in the axial direction of the rotary atomizing head and as a result, the atomization of the paint becomes insufficient and the paint sagging easily occurs on the workpiece.

And according to this rotary atomizing coating apparatus, air is supplied to each spiral flow formation chamber after the pressure is made uniform by the manifold. Therefore, a uniform spiral flow is ejected from each shaping air ejection hole. Further, the spiral flow can be easily generated by the spiral flow forming chamber. Therefore, it is possible to realize a rotary atomizing coating apparatus that can easily generate a spiral flow using a general-purpose apparatus main body.

  Further, according to the present invention, the spiral flow forming chamber has a cylindrical portion in which the inclined supply hole is formed at a rear end, a diameter thereof is reduced from the front end of the cylindrical portion toward the front, and the shaping air ejection hole is formed at the front end. And an established conical section.

  According to this rotary atomizing coating apparatus, the spiral flow generated in the cylindrical portion can be ejected from the shaping air ejection hole at high speed and high rotation by the conical portion.

  According to the present invention, even when the amount of shaping air or the flow velocity is not increased as in the prior art, when a narrow and deep recess is formed in a workpiece having a complicated shape such as a bumper, a predetermined cycle time is determined. Thus, a sufficient amount of atomized paint can reach the bottom surface of the recess. Therefore, automatic painting of only the rotary atomizing coating apparatus is possible without requiring supplementary work by an operator in a subsequent process.

It is a front view of the rotary atomization coating apparatus which concerns on 1st Embodiment of this invention. It is a partial side view of the rotary atomization coating apparatus which concerns on 1st Embodiment of this invention. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG. It is EE sectional drawing in FIG. FIG. 4 is an enlarged view around a spiral flow forming chamber in FIG. 3. It is a front view of the rotary atomization coating apparatus which concerns on 2nd Embodiment of this invention. It is FF sectional drawing in FIG. It is GG sectional drawing in FIG. It is HH sectional drawing in FIG. It is a front view of the rotary atomization coating apparatus which shows a mode that the rotation direction of a spiral flow is the same direction as the rotation direction of a rotary atomization head. (A) is an enlarged view of the spiral flow forming chamber in FIG. 4, and (b) is an enlarged view of the spiral flow forming chamber when the rotational direction of the spiral flow is set to be opposite to (a).

“First Embodiment”
Hereinafter, the vertical direction in FIG. 3 will be described as the front-back direction. In FIG. 3, the rotary atomizing coating apparatus P of the present invention includes a cylindrical apparatus body 1 in which a rotary shaft 2 is coaxially supported. Around the front end of the rotary shaft 2 protrudes from the front end surface of the apparatus main body 1, and a rotary atomizing head (bell cup) 3 is attached to the tip. The rotary atomizing head 3 has a truncated cone shape whose diameter increases toward the front. A paint supply path 4 is formed in the rotary shaft 2, and the front end side of the paint supply path 4 communicates with the rotary atomizing head 3.

  A shaping ring 5 is attached to the front end surface of the apparatus main body 1. A central aperture 6 is formed through the shaping ring 5, and the front end side of the central aperture 6 is formed as a conical space following the outer peripheral conical surface of the rotary atomizing head 3. The rotary shaft 2 is inserted through the central aperture 6, and the rotary atomizing head 3 has a conical shape of the central aperture 6 around its rear end so that the outer peripheral conical surface is spaced from the conical surface of the central aperture 6. Located in space. The circumference of the front end of the rotary atomizing head 3 protrudes forward from the conical space of the central aperture 6 and protrudes from the front end surface of the shaping ring 5.

  On the rear end surface of the shaping ring 5 (surface in contact with the front end surface of the apparatus main body 1), a manifold 7 having an annular shape and a rectangular groove shape is formed around the axis O of the rotary atomizing head 3. The manifold 7 communicates with a plurality of shaping air supply paths 8 formed in the apparatus main body 1. In the shaping ring 5, a plurality of spiral flow forming chambers 9 are formed at equal intervals around the axis O as shown in FIG. Each spiral flow forming chamber 9 includes a cylindrical portion 10 forming a cylindrical space, and a conical portion 11 forming a conical space whose diameter decreases from the front end of the cylindrical portion 10 toward the front.

  The spiral flow forming chamber 9 is formed, for example, on the annular center circumferential line D1 (see FIG. 4) of the manifold 7 as the chamber center X1 (see FIG. 12), and the diameter of the cylindrical portion 10 which is the maximum diameter of the chamber. The dimensions are, for example, the same as the radial width dimensions of the manifold 7. A shaping air ejection hole 13 is opened from the front end of the conical portion 11 to the front end surface of the shaping ring 5 in parallel with the axis O. As shown in FIG. 1, the shaping air ejection hole 13 rotates around the hole centered on a circumferential line (annular center circumferential line D1) slightly larger than the front end diameter of the rotary atomizing head 3. The hole diameter is such that it is positioned outside the front end diameter of the atomizing head 3 and is formed at equal intervals in the circumferential direction.

  In FIG. 3, the cylindrical portion 10 of each spiral flow forming chamber 9 and the manifold 7 communicate with each other through inclined supply holes 12 formed around the axis O at equal intervals. As can be seen from FIG. 3, the inclined supply hole 12 is a hole that forms an inclination angle with respect to the axis O in a side view. The inclined supply hole 12 faces the front end face of the manifold 7 through the opening 12a, and faces the rear end face of the cylindrical portion 10 through the opening 12b. The inclined supply hole 12 has a constant hole diameter from the opening 12a to the opening 12b as shown by a dotted line in FIG. 3, and FIG. 3 is a view taken along the line AA in FIG. A solid line indicates that the hole diameter changes from the hole 12a to the opening 12b.

  The inclined supply hole 12 is drilled in such a direction that air flowing into the spiral flow forming chamber 9 from the opening 12b of the inclined supply hole 12 can collide with the inner peripheral surface of the spiral flow forming chamber 9 to generate a spiral flow. Yes. FIG. 12A is an enlarged view of one spiral flow forming chamber 9 in FIG. The opening 12a is formed with the hole center X2 on the circumferential line D2 having a smaller diameter than the annular center circumferential line D1 and a larger diameter than the inner circumferential surface 7a (FIG. 4) of the manifold 7. The opening 12b is formed with a hole center X3 on a circumferential line D3 having a diameter larger than that of the annular center circumferential line D1 and smaller than that of the outer peripheral surface 7b of the manifold 7 (FIG. 4).

  When the hole center X3 of the opening 12b is positioned on one side with respect to a line passing through the hole center X2 and the chamber center X1 of the opening 12a in a plan view state, the opening 12b extends to the cylindrical portion 10. The air that has flowed in strikes the inner peripheral surface of the cylindrical portion 10 at an angle, and then flows in the counterclockwise direction in FIG. 12A along the inner peripheral surface. Thereby, as shown in FIG. 1, the spiral flow S which rotates in the direction opposite to the rotation direction K of the rotary atomizing head 3 is generated.

  If the spiral flow S rotating in the same direction as the rotation direction K of the rotary atomizing head 3 is generated as shown in FIG. 11, the hole center of the opening 12a is shown in FIG. The inclined supply hole 12 is drilled so that the hole center X3 of the opening 12b is positioned on the other side with respect to a line passing through X2 and the chamber center X1. As a result, the air flowing into the cylindrical portion 10 from the opening 12b collides with the inner peripheral surface of the cylindrical portion 10 obliquely in the direction opposite to that in FIG. 12A, and then along the inner peripheral surface in FIG. As shown in FIG. 11, a spiral flow S that rotates in the same direction as the rotation direction K of the rotary atomizing head 3 is generated.

The effect | action of the rotary atomization coating apparatus P which consists of the above structure is demonstrated.
The pressure of the air supplied to the manifold 7 via the shaping air supply path 8 is equalized in the manifold 7 which is this annular space. Next, air is supplied from the manifold 7 to the cylindrical portion 10 of each spiral flow forming chamber 9 via the inclined supply hole 12. At this time, the air obliquely collides with the inner peripheral surface of the cylindrical portion 10 depending on the direction of the inclined supply hole 12. As a result, a spiral flow S is generated in the cylindrical portion 10 that runs forward along the inner peripheral surface thereof and that rotates in the direction opposite to the rotation direction K of the rotary atomizing head 3 in the present embodiment. In this case, “rotate in the opposite direction” means that the spiral flow S rotates clockwise when the rotary atomizing head 3 rotates, for example, counterclockwise in a plan view seen from one direction as shown in FIG. It means to do.

  Then, the spiral flow S that rises forward along the inner peripheral surface of the cylindrical portion 10 is gradually reduced in diameter by the conical portion 11 as shown in FIG. As a result, the shaping air becomes a high-speed and high-rotation spiral flow S, and is ejected from the small-diameter shaping air ejection hole 13 so as to pass slightly outside the front end edge of the rotary atomizing head 3.

  On the other hand, the paint supplied to the rotary atomizing head 3 through the paint supply path 4 in the rotary shaft 2 spreads in a thin film on the inner surface of the rotary atomizing head 3 by the centrifugal force generated by the high speed rotation of the rotary atomizing head 3. After the high voltage is applied, the centrifugal force causes the atomization head 3 to spray from the front edge of the rotary atomizing head 3. At this time, the paint tends to scatter in the rotational direction K of the rotary atomizing head 3 and outward in the radial direction by the centrifugal force.

  However, scattering of the paint in the radially outward direction is suppressed by the spiral flow S. That is, as shown in FIG. 1, the shaping air ejection hole 13 is located on the periphery of the rotary atomizing head 3 in a plan view, that is, on a circumferential line slightly larger than the front end diameter of the rotary atomizing head 3. In addition, since the entire hole is located outside the front end diameter of the rotary atomizing head 3 and the direction of the hole is parallel to the axis of the rotary shaft 2, the spiral flow ejected from the shaping air ejection hole 13 S is formed linearly along the axial center of the rotary shaft 2 so as to pass a little around the front end edge of the rotary atomizing head 3. The paint to be scattered in the outward radial direction is blocked by the plurality of spiral flows S, narrowed down to an appropriate coating pattern diameter, and sprayed toward the workpiece. Further, the flow of the spiral flow S in the direction opposite to the rotational direction K of the rotary atomizing head 3 further promotes the atomization of the coating material, thereby obtaining good coating.

  Since the spiral flow S has a swirling component, it has high straightness. Further, the spiral flow S hardly generates a large negative pressure in front of the rotary atomizing head 3. Even if the amount or the flow velocity of the shaping air is increased, the spiral flow S itself acts so as to be prevented from spreading in the radial direction, so that the rotation atomization is performed as the amount of the shaping air or the flow velocity is increased. There is no problem that the negative pressure generated in front of the head 3 is increased. Therefore, the inconvenience that the shaping air is attracted in the direction of the rotational axis of the rotary atomizing head 3 and as a result, the atomization of the paint becomes insufficient and the paint sagging easily occurs on the workpiece.

  According to the present invention, the shaping air composed of the spiral flow S is kept highly straight along the axis of the rotary shaft 2. Therefore, even if the amount of shaping air or the flow velocity is not increased as in the conventional case, a narrow and deep concave portion is formed in a workpiece having a complicated shape such as a bumper, for example, a short time (predetermined cycle time). Thus, a sufficient amount of atomized paint can be made to reach the bottom surface of the recess, and only the rotary atomizing coating apparatus P can be automatically coated without requiring supplementary work by an operator in a subsequent process.

  A shaping ring 5 attached to the front end of the apparatus main body 1 is formed in an annular shape around the axis O of the rotary atomizing head 3 and communicates with the shaping air supply path 8 of the apparatus main body 1. Are arranged around the axis O in front of each other, communicate with the manifold 7 via the inclined supply holes 12, respectively, and the spiral flowing in from the inclined supply holes 12 collides with the inner peripheral surface of the spiral. If the flow forming chambers 9 and the shaping air ejection holes 13 communicating with the spiral flow forming chambers 9 are used, the air is supplied to the spiral flow forming chambers 9 after the pressure is made uniform by the manifold 7. The Therefore, a uniform spiral flow S is ejected from each shaping air ejection hole 13. Further, the spiral flow S can be easily generated by the spiral flow forming chamber 9. Therefore, the rotary atomizing coating apparatus P which can generate | occur | produce the spiral flow S easily using the general purpose apparatus main body 1 is realizable.

  Furthermore, the diameter of the spiral flow forming chamber 9 was reduced from the front end of the cylindrical portion 10 to the front, and a shaping air ejection hole 13 was formed at the front end. With the conical portion 11, the spiral flow S generated in the cylindrical portion 10 can be ejected from the shaping air ejection hole 13 at a high speed and a high rotation speed by the conical portion 11.

“Second Embodiment”
Next, a second embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same component as 1st Embodiment, and the description is abbreviate | omitted. The second embodiment is mainly characterized in that a plurality of second shaping air ejection holes 14 are provided in the circumferential direction in the shaping ring 5 so as to be concentric with the shaping air ejection holes 13 on the inner diameter side. .

  A second manifold 15 having an annular shape and a rectangular groove shape is formed in the rear end surface of the shaping ring 5, and a plurality of second shaping air supply passages 16 are opened in the apparatus main body 1 so as to communicate with the second manifold 15. Has been. At the rear end of the conical space in the central opening 6 of the shaping ring 5, an annular step surface 17 that forms a plane orthogonal to the axis O is formed. The second shaping air ejection hole 14 is opened so that the rear end thereof communicates with the second manifold 15 and the front end faces the front end edge of the rotary atomizing head 3 on the stepped surface 17.

  The second shaping air ejected from the second shaping air ejection hole 14 is supplied to the front end edge of the rotary atomizing head 3 along the outer peripheral conical surface of the rotating rotary atomizing head 3. The paint is further atomized by this second shaping air. Since the second shaping air is interposed between the paint sprayed from the front end edge of the rotary atomizing head 3 and the spiral flow S, the coating pattern of the paint is controlled by controlling the amount or flow velocity of the second shaping air. Can be controlled with higher accuracy.

  The preferred embodiment of the present invention has been described above. In the described embodiment, the shaping ring 5 is a single member, but may be divided into a plurality of members. Further, the rotation direction of the spiral flow S is not limited to the direction opposite to the rotation direction K of the rotary atomizing head 3, and as described in FIG. 11 and FIG. The rotation direction K may be the same direction.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Rotating shaft 3 Rotating atomization head 5 Shaping ring 7 Manifold 8 Shaping air supply path 9 Spiral flow formation chamber 10 Cylindrical part 11 Conical part 12 Inclined supply hole 13 Shaping air ejection hole P Rotating atomization coating apparatus

Claims (2)

A rotary atomizing head that sprays the paint forward and radially outward is provided, and shaping air is ejected from the plurality of shaping air ejection holes arranged around the rear of the rotary atomizing head toward the front edge of the rotary atomizing head. In a rotary atomizing coating device that forms a paint coating pattern,
An apparatus main body in which a shaping air supply path is formed, and a shaping ring attached to the front end of the apparatus main body,
The shaping ring is
A manifold formed in an annular shape around the axis of the rotary atomizing head and communicating with the shaping air supply path;
A plurality of spirals arranged around the shaft center in front of the manifold, communicated with the manifold via respective inclined supply holes, and generate a spiral flow when air flowing from the inclined supply holes collides with the inner peripheral surface thereof. A flow forming chamber;
The shaping air ejection holes communicating with the spiral flow forming chambers;
Have
A rotary atomizing coating apparatus, wherein shaping air is ejected as a spiral flow from each of the shaping air ejection holes. The spiral flow forming chamber is
A cylindrical portion in which the inclined supply hole is opened at the rear end;
The diameter of the cylindrical portion decreases from the front end toward the front, and the conical portion in which the shaping air ejection hole is opened at the front end;
The rotary atomizing coating apparatus according to claim 1 , comprising:

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