JP2013071050A - Coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily wash a coating material spray member and a coating material supply means.SOLUTION: A coating apparatus 10 includes a hollow rotary shaft 14 rotated at a high speed by an air motor 12, a rotary atomizing head 16 provided on the distal end of the rotary shaft 14, and a pipe member 18 inserted into the inside of the rotary shaft 14. To a small diameter part 24 of the pipe member 18, an outer pipe forming member 28 is externally fitted. The distal end of the outer pipe forming member 28 is inserted to a housing hole 46 formed at the rotary atomizing head 16. The outer peripheral wall of the distal end of the outer pipe forming member 28 and the inner wall of the housing hole 46 are separated at a prescribed interval, and thus an annular clearance (a gap 52 for coating material distribution) is formed. Openings (coating material supply ports) of a plurality of coating material discharge holes 38 formed in the outer peripheral wall of the outer pipe forming member 28 face the inner wall of the housing hole 46.

Description

  The present invention relates to a coating apparatus that performs coating by spraying a paint on an object to be coated.

  As a coating apparatus for coating an object to be painted such as an automobile body, a rotary atomization type apparatus has been widely used.

  The rotary atomizing type coating apparatus includes a housing and a rotary atomizing head as a paint spraying member exposed from the housing (see, for example, Patent Document 1). A rotation shaft for rotating the rotary atomizing head is accommodated in the housing, and a paint supply passage for supplying paint to the rotary atomizing head is formed on the rotary shaft. The paint supply passage is opened at the approximate center of the front end surface along the surface of the rotary atomizing head.

  When painting, the rotating shaft starts rotating under the action of a rotation urging means such as an air motor, and the rotating atomizing head rotates accordingly. Next, the paint supplied from the paint supply source is sent to the creeping surface of the rotary atomizing head via the paint supply passage.

  On the creeping surface of the rotary atomizing head, the paint derived from substantially the center is directed outward by centrifugal force. That is, it moves to the edge. After that, the paint becomes a so-called liquid thread state, jumps out from the edge, is atomized by the air discharged from the housing toward the object to be coated, becomes a mist (mist), and in this state, Along with the air, it flies toward the object to be painted. That is, the paint is sprayed. The paint is electrically negatively charged, while the object to be painted is grounded. Therefore, the paint can easily fly toward the object to be coated.

  Finally, the paint adheres to the object to be coated. Thereby, painting is performed.

JP 2005-118710 A

  When performing coating by switching from an arbitrary color paint to another color paint, that is, so-called color change, it is necessary to clean the path through which the paint flowed in order to avoid color mixing. In the above-described coating apparatus according to the prior art, when changing the color of paint with high viscosity or paint that is not easy to clean, in some cases, the rotary atomizing head is removed from the housing, cleaned, and then reinstalled. Although it may be performed, it is complicated to perform such an operation.

  However, it is difficult to clean the inner wall facing the paint reservoir space formed in the rotary atomizing head and the paint discharge hole without removing the rotary atomizing head from the housing. For these reasons, it is necessary to remove the rotary atomizing head and replace it with a new rotary atomizing head that has been cleaned in advance.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a coating apparatus that can be easily cleaned without removing a paint spraying member at the time of cleaning.

In order to achieve the above-mentioned object, the present invention is a coating apparatus for performing coating by spraying a paint on an object to be coated,
A paint spraying member for spraying from the edge the paint supplied to the creeping surface facing the object while rotating by the rotation urging means,
Paint supply means for supplying paint to the paint spraying member;
Have
The paint spraying member is formed with an accommodation hole for inserting and accommodating the paint supply means,
And the clearance opened by the creeping surface of the said coating material spray member is formed between the inner wall of the said accommodation hole, and the said coating material supply means, It is characterized by the above-mentioned.

  When the paint cannot be sufficiently removed only by distributing the cleaning agent, cleaning may be performed by inserting a cleaning tool such as a cleaning brush into the clearance. For this reason, the paint spray member and the paint supply means can be easily cleaned without removing the paint spray member.

  Further, since it is not particularly necessary to perform complicated removal / reinstallation work, the efficiency of the cleaning work is also improved.

  In this configuration, a plurality of paint supply ports may be formed at a portion facing the inner wall of the housing hole in the paint supply means. In this case, when coating is performed, the paint is supplied to the inner wall of the accommodation hole of the rotating paint spray member and collides with the inner wall. The paint is then subjected to a shearing force, resulting in a decrease in viscosity.

  Since the paint having such a reduced viscosity easily flows along the creeping surface of the paint spraying member, the thickness of the coating film flowing along the creeping surface is reduced. Therefore, when the coating material that has flowed along the creeping surface becomes a coating particle and diffuses by a conveying gas (for example, compressed air), it becomes extremely fine. For this reason, it is possible to avoid the occurrence of uneven coating and the occurrence of variations in the thickness of the coating film. Thereby, it becomes possible to obtain a high-quality coating film.

  It is preferable that the paint supply ports are spaced apart at equal angles in the circumferential direction, and the opening areas of the paint supply ports are all set to be the same. In this case, since the cleaning agent is evenly distributed to each paint supply port, the cleaning proceeds evenly. Accordingly, it is possible to avoid that the amount of the cleaning agent distributed to the coating material supply port becomes insufficient and that the coating material remains for this reason.

  The paint supply means may be configured to include a hub in addition to the paint supply pipe.

  By the way, when spraying the paint from the edge of the creeping surface facing the object to be coated of the paint spraying member, the air in the vicinity of the center of the creeping surface may be caught in the coating grain in some cases. In this case, there is a concern that a negative pressure region is generated and the coated grains are attracted to cause convection. If such a situation occurs, the spray pattern may be disturbed, or the paint may adhere to the tip of the paint supply pipe and cause contamination.

  Therefore, it is preferable to open a gas discharge port on the creeping surface of the paint spraying member and discharge gas (for example, compressed air) from the approximate center of the creeping surface of the paint spraying member. As a result, a large amount of gas is present in the vicinity of the discharge location. For this reason, since it is prevented that a negative pressure area | region generate | occur | produces, it can avoid that the above malfunctions are induced.

  According to the present invention, the clearance is formed by separating the inner wall of the accommodation hole formed in the paint spraying member and the paint supply means inserted / accommodated in the accommodation hole at a predetermined interval. It is possible to easily insert a cleaning tool into the clearance. For this reason, the inner wall of the accommodation hole and the paint supply means can be easily cleaned without removing the paint spraying member.

  Therefore, since the cleaning efficiency is improved, for example, it is possible to shorten the time from the end of painting with an arbitrary color paint to the start of painting with another color paint. That is, color change can be performed quickly.

It is a principal part schematic sectional drawing of the coating device which concerns on 1st Embodiment of this invention. It is a whole schematic perspective view of the outer tube formation member which constitutes the above-mentioned painting device. It is a principal part schematic sectional drawing of the coating device which concerns on 2nd Embodiment of this invention. It is a whole schematic perspective view of the hub which comprises the said coating apparatus. It is a principal part schematic sectional drawing of the coating device in which the cyclic | annular recessed part was formed in the rotary atomization head.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a coating apparatus according to the present invention will be given and described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view of a main part of a coating apparatus 10 according to the first embodiment of the present invention. The coating apparatus 10 is provided, for example, on the tip arm of an articulated robot (not shown). The articulated robot is, for example, a 5-axis or 6-axis robot.

  The coating apparatus 10 has a casing (not shown), and an air motor 12 and a rotating shaft 14 that rotates at high speed under the action of the air motor 12 are accommodated in the casing. That is, the air motor 12 is a rotation urging unit that rotates the rotating shaft 14 at a high speed when compressed air is supplied from a compressed air supply source (not shown).

  The rotating shaft 14 is electrically connected to a high voltage generator (not shown) that generates a high voltage. Therefore, a negative high voltage is applied to the bell cup-shaped rotary atomizing head 16 (paint spray member) provided at the tip of the rotary shaft 14 via the rotary shaft 14.

  Moreover, the rotating shaft 14 is a hollow member opened at both ends, and a pipe member 18 (paint supply pipe) is inserted therein.

  The tube member 18 is fixed to the casing via a fixed support member 20. Therefore, the pipe member 18 does not rotate.

  The tube member 18 includes a large diameter portion 22 supported by the fixed support member 20 and a small diameter portion 24 which is located on the X1 direction side and is smaller in diameter than the large diameter portion 22. The small-diameter portion 24 therein is a hollow portion whose end portion in the X1 direction is opened as the air discharge port 26, and most of the small-diameter portion 24 protrudes from the opening of the rotating shaft 14. An outer pipe forming member 28 (paint supply pipe) is fitted on the outer peripheral wall of the protruding portion. In the first embodiment, the paint supply means is configured to include two paint supply pipes of the pipe member 18 and the outer pipe forming member 28. Since the tube member 18 does not rotate, the outer tube forming member 28 also does not rotate. That is, the paint supply means is a non-rotating body.

  A large-diameter insertion port 30 into which the small-diameter portion 24 is inserted is formed at the end portion of the outer tube forming member 28 in the X2 direction. On the other hand, an opening 32 that faces the air discharge port 26 formed at the X1 direction end of the small diameter portion 24 is formed at the X1 direction end. The diameter of the opening 32 substantially matches the outer diameter of the small diameter portion 24. In addition, the periphery of the opening 32 (and the air discharge port 26) is surrounded by a tapered surface 34 whose diameter is increased in a tapered shape. The insertion port 30 is reduced in diameter toward the opening 32 (and the air discharge port 26).

  The outer tube forming member 28 further includes an annular communication passage 36 that communicates with the insertion port 30 and extends in the longitudinal direction of the outer tube formation member 28, and a plurality of paint discharge holes ( A paint discharge passage 38) is formed. The paint discharge hole 38 extends in a direction substantially orthogonal to the communication path 36 and opens at the outer peripheral wall of the outer tube forming member 28 as shown in FIG. Accordingly, the plurality of paint discharge holes 38 are formed radially from the approximate center in the diameter direction of the outer tube forming member 28 toward the outer peripheral wall.

  The paint discharge holes 38 are preferably spaced apart from each other at equal intervals along the circumferential direction of the outer tube forming member 28. Furthermore, the hole diameters and opening diameters of all the paint discharge holes 38, and thus the cross-sectional areas and the opening areas. Are preferably identical to each other. By being spaced apart from each other at equal intervals and having the same cross-sectional area and opening area, the paint introduced into the insertion port 30 is evenly distributed to the paint discharge holes 38. Accordingly, the paint is uniformly led out from each paint discharge hole 38.

  The inner walls of the insertion port 30 and the communication path 36 of the outer tube forming member 28 formed in this way are separated from the outer peripheral wall of the small diameter portion 24 by a predetermined distance. That is, a clearance is formed in an annular shape between the outer peripheral wall of the small diameter portion 24 and the inner wall of the outer tube forming member 28. Therefore, the small diameter portion 24 of the tube member 18 functions as an inner tube, while the outer tube forming member 28 whose inner wall is separated from the outer peripheral wall of the small diameter portion 24 functions as an outer tube.

  More specifically, an air passage 40 and a paint passage 42 are formed from the fixed support member 20 to the pipe member 18. The air passage 40 therein extends to the end of the small diameter portion 24 in the X1 direction and opens. On the other hand, the paint passage 42 opens near the boundary between the large diameter portion 22 and the small diameter portion 24 (not shown) and communicates with the insertion port 30. Of course, the opening of the paint passage 42 is covered with the outer tube forming member 28, so that the paint does not leak into the rotary shaft 14.

  The paint passage 42 is connected to a paint supply source (not shown) such as a paint filling cylinder and a cleaning liquid supply source, while the air passage 40 is connected to a compressed air supply source (such as an industrial air line). .

  An engagement hole 44 with which the rotary shaft 14 is engaged is formed at the end of the rotary atomizing head 16 in the X2 direction. The end of the X1 direction communicates with the engagement hole 44 and extends from the X1 direction to the X2 direction. An accommodation hole 46 that is tapered in a tapered shape is formed. A portion of the outer tube forming member 28 that protrudes from the engagement hole 44 is inserted into the accommodation hole 46. Accordingly, the end portion in the X1 direction of the outer tube forming member 28 is surrounded by the rotary atomizing head 16, and the opening (paint supply port) of the paint discharge hole 38 faces the inner wall of the accommodation hole 46.

  Here, an annular recess 48 is formed around the portion of the inner wall of the accommodation hole 46 that faces the opening of the paint discharge hole 38. As will be described later, the paint discharged from the opening of the paint discharge hole 38 is temporarily stored in the annular recess 48.

  The accommodation hole 46 extends while expanding in a tapered shape toward the rotary atomizing head 16, and opens at a creeping surface 50 that is a front end surface of the rotary atomizing head 16. The paint discharged from the opening of the paint discharge hole 38 circulates toward the creepage surface 50 along the inner wall of the accommodation hole 46. That is, the clearance between the outer peripheral wall of the outer tube forming member 28 and the inner wall of the accommodation hole 46 becomes a flow path for the paint. Hereinafter, this clearance is referred to as a paint distribution gap, and its reference numeral is 52.

  The creeping surface 50 is slightly inclined so as to be directed toward the arrow X1 direction as it becomes radially outward. When the rotary atomizing head 16 rotates following the rotation of the rotating shaft 14, the coating material flowing on the creeping surface 50 is thinned by centrifugal force to be in a so-called liquid yarn state.

  The coating material in the liquid yarn state becomes mist by compressed air discharged from an air outlet (not shown) provided in the casing, and in this state, is sprayed on an object not shown.

  The coating apparatus 10 according to the first embodiment is basically configured as described above. Next, the operation and effect will be described in relation to a coating method.

  The object to be coated moves gently along the transfer line and is carried into a painting booth (not shown). The object to be painted is grounded in advance.

  When the object to be coated is carried into the painting booth in this way, the articulated robot performs an appropriate operation to move the coating apparatus 10 so as to face the object to be coated.

  In this state, the air motor 12 is energized and the rotating shaft 14 starts high-speed rotation. Accordingly, the rotary atomizing head 16 attached to the rotary shaft 14 also rotates at a high speed. Further, the high voltage generator is energized, and the rotary atomizing head 16 is negatively charged. Further, compressed air is discharged from the air jet outlet.

  Next, the paint is sent out from the paint supply source (paint filling cylinder or the like) and introduced between the inner wall of the insertion port 30 of the outer tube forming member 28 and the tube member 18 through the paint passage 42. The paint further passes through the insertion port 30 and the communication path 36 and flows through a plurality of paint discharge holes 38 communicating with the communication path 36. The paint is discharged from the opening (paint supply port) of the paint discharge hole 38.

  As described above, the coating material discharge holes 38 are spaced apart from each other at equal intervals along the circumferential direction of the outer tube forming member 28 and the cross-sectional area and the opening area of the coating material discharge hole 38 are all the same. Is evenly distributed to each of the paint discharge holes 38. Accordingly, the paint is uniformly led out from each paint discharge hole 38.

  The discharged paint travels toward the accommodation hole 46 formed in the rotary atomizing head 16 rotating at high speed. And it is once stored by the annular recessed part 48 formed in the inner wall of the accommodation hole 46. FIG. That is, the annular recess 48 functions as a paint reservoir. The coating material stored in the annular recess 48 then overflows from the annular recess 48 and then flows along the inner wall of the accommodation hole 46.

  When the annular recess 48 does not exist, there is a concern that the paint discharged from the paint discharge hole 38 rebounds from the inner wall of the accommodation hole 46 and falls as a spit without passing through the inner wall. When such a situation occurs, it causes a coating film defect.

  On the other hand, in the first embodiment, since the paint is temporarily stored in the annular recess 48 as described above, the paint flows along the inner wall of the accommodation hole 46 after overflowing from the annular recess 48. Easily flows. For this reason, it can avoid that a coating material falls as a spit.

  As described above, once the paint is temporarily stored in the annular recess 48 that is a paint reservoir, the paint is easily transmitted through the inner wall of the accommodation hole 46. Thereby, it can avoid that a coating-film defect arises.

  Further, in the first embodiment, the paint discharge hole 38 of the outer tube forming member 28 that is stationary without rotating with respect to the inner wall (the bottom wall of the annular recess 48) of the receiving hole 46 of the rotary atomizing head 16 that rotates. The paint supplied from the opening collides. The paint receives a shearing force in this collision. As a result, the viscosity of the paint decreases.

  That is, the paint is discharged from the accommodation hole 46 to the creeping surface 50 of the rotary atomizing head 16 in a state where the viscosity is lowered. The paint that has reached the creeping surface 50 flows toward the outside in the diameter direction (outer peripheral edge) of the creeping surface 50 by the action of centrifugal force. Here, since the rotary atomizing head 16 is in a negatively charged state, the paint is negatively charged in the process of flowing on the inner wall and the creeping surface 50 of the accommodation hole 46 as described above.

  In the process of flowing along the creeping surface 50 toward the outer peripheral edge, the coating material is thinned by centrifugal force to be in a liquid yarn state. As described above, since the viscosity of the paint is lowered, the paint easily flows along the creeping surface 50. Accordingly, the thickness of the liquid yarn (paint thin film) is reduced.

  The liquid yarn is spread as a coating grain under the action of the compressed air discharged from the air outlet and becomes a mist state. Since the thickness of the liquid yarn is small, the coating particles are formed in a general prior art coating apparatus in which a coating material supply pipe is opened at the creeping surface 50 of the rotary atomizing head 16 and the coating material is discharged from the opening. It is remarkably fine compared to.

  The coated grains are sprayed from the outer peripheral edge of the creeping surface 50 toward the object to be coated. As described above, since the object to be coated is grounded and the paint is negatively charged, most of the coated particles fly while being attracted to the object to be coated, and finally are applied to the object to be coated. Thereby, painting is implemented. At this time, the spray pattern of the coated particles, and thus the coating pattern, is adjusted by controlling the discharge amount of the compressed air from the air ejection port.

  In the first embodiment, since the coating material is subjected to a shearing force when discharged from the coating material discharge hole 38, the coating grains are extremely fine. For this reason, it is possible to avoid the occurrence of uneven coating and the occurrence of variations in the thickness of the coating film. Thereby, the quality improvement of a coating film can be aimed at.

  When spraying the coating particles as described above, depending on the case, the atmosphere is involved in the spray flow of the coating particles in the approximate center of the front end surface of the creeping surface 50, that is, in the vicinity of the air discharge port 26 of the pipe member 18. As a result, a negative pressure region may be easily generated. If a negative pressure region is generated, coating particles are attracted to the negative pressure region and convection occurs. This convection causes the spray pattern to be disturbed, or the coating particles to adhere to the distal end portion of the tube member 18 (small diameter portion 24), resulting in contamination.

  Therefore, it is preferable to discharge air through the air discharge port 26 and the opening 32 of the outer tube forming member 28. This air prevents a negative pressure region from being generated in the vicinity of the air discharge port 26. Therefore, the concern that the above-described problems are caused is eliminated.

  After the spraying of the coating particles is finished, any remaining paint is discharged and washed. That is, the supply of the paint from the paint supply source is stopped and the paint supply valve (not shown) is closed, the supply of the cleaning liquid from the cleaning liquid supply source is started, and the cleaning liquid supply valve (not shown) is opened. As a result, the cleaning liquid starts to flow through the paint passage 42.

  The cleaning fluid flows in the same path as the paint. That is, the tube member 18 reaches the paint discharge hole 38 via the insertion port 30 and the communication path 36 of the outer tube forming member 28. Here, if the cross-sectional areas and the opening areas of the paint discharge holes 38 are all equal, the cleaning liquid is evenly distributed to the paint discharge holes 38. Therefore, it is easy to clean all the paint discharge holes 38.

  After the paint is discharged from the opening of the paint discharge hole 38, it is guided from the front end face of the creeping surface 50 of the rotary atomizing head 16 through the inner wall of the receiving hole 46 of the rotary atomizing head 16.

  The rotary atomizing head 16 is preferably rotated in the same manner as when painting. In this case, because the cleaning agent diffuses over substantially the entire creepage surface 50 by centrifugal force, the entire creepage surface 50 can be efficiently cleaned.

  In this way, since the coating material distribution gap 52, that is, the clearance is formed between the outer peripheral wall of the outer tube forming member 28 and the inner wall of the receiving hole 46, the outer peripheral wall of the outer tube forming member 28 and the receiving hole 46 are formed. It is easy to clean the inner wall. In addition, in this case, it is not particularly necessary to remove the rotary atomizing head 16. Therefore, cleaning can be performed efficiently.

  Next, a coating apparatus according to a second embodiment of the present invention will be described. In addition, about the component same as the coating device 10 which concerns on 1st Embodiment, the same referential mark is attached | subjected and the detailed description is abbreviate | omitted. However, even when the components are the same, they may be described with different reference numerals attached if necessary.

  FIG. 3 is a schematic cross-sectional view of a main part of a coating apparatus 70 according to the second embodiment. The coating apparatus 70 is different from the coating apparatus 10 according to the first embodiment in that a hub 72 is provided on the distal end side of the pipe member 18.

  The air motor 12 and the rotating shaft 14 are accommodated in a casing (not shown) constituting the coating apparatus 70. Of course, the rotating shaft 14 rotates at high speed under the action of the air motor 12.

  A tube member 18 having a large diameter portion 22 fixed to the casing is inserted into the hollow rotary shaft 14 via a fixed support member 20. In this case, most of the small diameter portion 24 of the tube member 18 protrudes from the opening of the rotating shaft 14. On the other hand, the outer tube forming member 73 has a small-diameter tip portion 74 extending in the X1 direction side, and a portion of the small-diameter tip portion 74 protruding from the opening of the rotating shaft 14 is surrounded by the small-diameter tip portion 74. The remaining portion is further exposed from the small diameter tip portion 74.

  In the second embodiment, an annular clearance formed between the outer peripheral wall of the small diameter portion 24 and the inner wall of the small diameter distal end portion 74 of the outer tube forming member 73 becomes the communication path 36. That is, in this case, the hollow small-diameter portion 24 of the tube member 18 functions as an inner tube, while the small-diameter tip portion 74 that forms the communication path 36 between the tube member 18 functions as an outer tube.

  The hub 72 is fitted to the small diameter portion 24 and the small diameter tip portion 74. That is, the hub 72 is formed with an insertion hole 76 extending along the axial direction thereof, and the distal end portions of the small diameter portion 24 and the outer tube forming member 73 are fitted into the insertion hole 76. The hub 72 has a substantially frustoconical shape, and the diameter decreases in a taper shape from the X1 direction toward the X2 direction.

  An engagement convex portion 78 is formed on the small-diameter distal end portion 74 of the outer tube forming member 73 so as to protrude in an annular shape along the circumferential direction. On the other hand, at the end of the hub 72 with the smallest diameter in the X2 direction, an engagement recess 80 that is depressed in an annular shape along the circumferential direction is formed. The engagement protrusion 78 is engaged with the engagement recess 80. Match. By this engagement, the hub 72 is positioned and fixed with respect to the outer tube forming member 73.

  Here, at least a portion of the hub 72 where the engagement recess 80 is formed is made of an elastic material such as rubber or resin. Therefore, this part is easily elastically deformed (expanded) when the engaging convex part 78 is passed through the insertion hole 76, and when the positions of the engaging convex part 78 and the engaging concave part 80 are matched, the elastic recovery is performed. It returns to its original shape by force. Thereby, the engagement convex part 78 and the engagement recessed part 80 mutually engage.

  As in the first embodiment, the tube member 18 does not rotate. Therefore, the outer tube forming member 73 and the hub 72 do not rotate.

  As shown in FIG. 4, the hub 72 is formed with a plurality of paint discharge holes (paint supply passages) 82 extending radially from the center in the diameter direction of the insertion hole 76 toward the outer wall. The opening provided at the tip of the outer tube forming member 73 faces the paint discharge hole 82. In other words, the communication passage 36 formed between the outer peripheral wall of the small-diameter portion 24 and the inner wall of the small-diameter tip portion 74 serves as a paint passage 42 that communicates with the paint discharge hole 82 and sends the paint to the paint discharge hole 82. Function.

  The paint discharge hole 82 opens at the side wall of the hub 72. This opening functions as a paint supply port. Also in this case, for the reasons described above, the paint discharge holes 82 are spaced apart from each other at equal intervals along the circumferential direction of the hub 72, and the cross-sectional area and the opening area of the paint discharge holes 82 are all the same. preferable.

  Further, the air passage 40 formed in the small diameter portion 24 opens at the front end surface of the hub 72 (see FIG. 3). In other words, the position of the opening of the air passage 40 and the position of the opening of the insertion hole 76 match each other.

  An engagement hole 44 with which the rotary shaft 14 is engaged is formed at the end of the rotary atomizing head 16 in the X2 direction, and the end of the X1 direction communicates with the engagement hole 44 and extends from the X1 direction to the X2 direction. An accommodation hole 46 that is tapered in a tapered shape is formed. The hub 72 is accommodated in the accommodation hole 46. Accordingly, the hub 72 is surrounded by the rotary atomizing head 16, and the paint supply port (opening of the paint discharge hole 82) formed in the hub 72 faces the inner wall of the accommodation hole 46.

  An annular paint distribution gap 84 is formed between the outer wall of the hub 72 and the inner wall of the accommodation hole 46. The coating material distribution gap 84 extends toward the rotary atomizing head 16 and opens at a creeping surface 50 that is a front end surface of the rotary atomizing head 16. The paint discharged from the opening (paint supply port) of the paint discharge hole 82 circulates toward the creeping surface 50 while traveling along the inner wall of the accommodation hole 46. That is, the coating material distribution gap 84 is a coating material flow path through which the coating material flows.

  As can be understood from the above, in the second embodiment, the pipe member 18, the outer pipe forming member 73, and the hub 72 constitute the paint supply means.

  Next, the effect of the coating apparatus 70 according to the second embodiment will be described in relation to a coating method.

  As in the first embodiment, the articulated robot performs an appropriate operation so that the coating apparatus 70 faces the object to be coated that has been moved gently along the transfer line and carried into the painting booth, as in the first embodiment. Run. Furthermore, as the air motor 12 is energized and the rotary shaft 14 starts to rotate at a high speed and the high voltage generator is energized, the rotary atomizing head 16 rotates at a high speed and becomes negatively charged. . Moreover, compressed air is discharged from the air outlet.

  Next, the paint is sent out from the paint supply source (paint filling cylinder or the like) and introduced between the inner wall of the insertion port 30 of the outer tube forming member 73 and the tube member 18 through the paint passage 42. The paint further passes through the insertion port 30 and the communication passage 36, flows into the paint discharge hole 82 formed in the hub 72, and is then discharged from the opening (paint supply port) of the paint discharge hole 82. When the paint discharge holes 82 are spaced apart from each other at equal intervals along the circumferential direction of the hub 72, and the cross-sectional area and the opening area of the paint discharge holes 82 are all the same, the paint is applied to each of the paint discharge holes 82. Are evenly distributed and are evenly led out from the openings of the paint discharge holes 82.

  The paint discharged from the paint discharge hole 82 of the hub 72 that is stationary without rotating collides with the inner wall of the accommodation hole 46 formed in the rotary atomizing head 16 rotating at high speed. Accordingly, in this case as well, the coating is subjected to shearing force, and as a result, the viscosity of the coating is lowered.

  The paint whose viscosity has been lowered is transmitted along the inner wall of the accommodation hole 46 by the action of centrifugal force, and the paint distribution gap 84 formed by the side wall of the hub 72 and the inner wall of the accommodation hole 46 is directed toward the creeping surface 50 side. Moving. The paint is then led out from an opening formed in the creeping surface 50.

  Thereafter, the object to be coated is applied in the same manner as in the first embodiment. Since the viscosity of the coating is reduced due to the shearing force, the thickness of the liquid yarn flowing on the creeping surface 50 of the rotary atomizing head 16 is sufficiently reduced. Becomes extremely fine. Accordingly, it is possible to avoid the occurrence of uneven coating and the variation in the thickness of the coating film, so that the coating quality can be improved.

  Of course, as in the first embodiment, air may be discharged through the air discharge port 26 and the opening of the front end surface of the hub 72 while spraying the coating grains. This air prevents the negative pressure region from being generated in the vicinity of the air discharge port 26, in other words, at the approximate center of the front surface of the creeping surface 50. Therefore, the occurrence of convection of the coated particles is avoided, and as a result, the spray pattern is disturbed and the coated particles are prevented from adhering to the distal end portion of the tube member 18 (small diameter portion 24).

  The cleaning may be performed in the same manner as in the first embodiment. That is, the supply of the paint from the paint supply source is stopped and the paint supply valve (not shown) is closed, the supply of the cleaning liquid from the cleaning liquid supply source is started, and the cleaning liquid supply valve (not shown) is opened. As a result, the cleaning liquid flows through the paint passage 42, the insertion port 30 of the outer tube forming member 73, the communication passage 36, and the paint discharge hole 82. When the cross-sectional area and the opening area of the paint discharge holes 82 are all equal, the cleaning liquid is evenly distributed to each paint discharge hole 82, so that it is easy to clean all the paint discharge holes 82.

  After the paint is discharged from the paint discharge hole 82, it is guided from the front end face of the creeping surface 50 of the rotary atomizing head 16 along the paint distribution gap 84 along the inner wall of the receiving hole 46 of the rotary atomizing head 16. Is done. If the rotary atomizing head 16 is rotated, the cleaning agent diffuses over substantially the entire creeping surface 50 by centrifugal force, so that the entire creeping surface 50 can be efficiently cleaned.

  If the outer wall of the hub 72 and the inner wall of the accommodation hole 46 are not sufficiently cleaned only by circulating the cleaning liquid, cleaning may be performed by inserting a cleaning brush or the like into the paint distribution gap 84. . As described above, in the second embodiment, since the coating material flow gap 84, that is, the clearance is formed between the outer wall of the hub 72 and the inner wall of the receiving hole 46, the outer wall of the hub 72 and the receiving hole 46 are formed. It is easy to clean the inner wall.

  In some cases, the hub 72 may be removed for cleaning. As described above, since at least the portion of the hub 72 where the engagement recess 80 is formed is made of an elastic material such as rubber or resin, when the hub 72 is removed, this portion is easily elastically deformed (expanded). Therefore, the hub 72 can be easily removed. Of course, as described above, when the hub 72 is attached, the engaging convex portion 78 and the engaging concave portion 80 can be easily engaged with each other.

  Thus, it is not particularly necessary to remove the rotary atomizing head 16 also in the second embodiment. Therefore, cleaning can be performed efficiently.

  The coating apparatuses 10 and 70 that are easy to clean as described above are particularly advantageous when spraying a paint of another color after spraying a paint of an arbitrary color and so-called color change.

  The present invention is not particularly limited to the first and second embodiments described above, and various modifications can be made without departing from the scope of the present invention.

  For example, also in the second embodiment, as shown in FIG. 5, an annular recess 90 that functions as a paint reservoir may be formed on the inner wall of the accommodation hole 46 that faces the opening of the paint discharge hole 82. In the first embodiment, the rotary atomizing head 16 may be configured without forming the annular recess 48.

DESCRIPTION OF SYMBOLS 10,70 ... Coating apparatus 12 ... Air motor 14 ... Rotating shaft 16 ... Rotating atomizing head 18 ... Pipe member 26 ... Air discharge port 28, 73 ... Outer tube formation member 30 ... Insertion port 36 ... Communication path 38, 82 ... Paint discharge Hole 40 ... Air passage 42 ... Paint passage 44 ... Engagement hole 46 ... Accommodating hole 48, 90 ... Annular recess 50 ... Creeping surface 52, 84 ... Paint distribution gap 72 ... Hub 78 ... Engagement projection 80 ... Engagement recess

Claims (5)

A coating device for spraying paint on an object to be coated.
A paint spraying member for spraying from the edge the paint supplied to the creeping surface facing the object while rotating by the rotation urging means,
Paint supply means for supplying paint to the paint spraying member;
Have
The paint spraying member is formed with an accommodation hole for inserting and accommodating the paint supply means,
In addition, the coating apparatus is characterized in that a clearance opened at the creeping surface of the paint spraying member is formed between the inner wall of the housing hole and the paint supply means.   2. The coating apparatus according to claim 1, wherein a plurality of paint supply ports are formed in a portion of the paint supply means facing the inner wall of the accommodation hole.   The coating apparatus according to claim 1 or 2, wherein the plurality of coating material supply ports are spaced apart from each other at an equal angle in the circumferential direction, and the total opening areas are equal to each other.   The coating apparatus of any one of Claims 1-3 WHEREIN: The said coating material supply means contains a hub, The coating apparatus characterized by the above-mentioned.   The coating apparatus according to any one of claims 1 to 4, wherein a gas discharge port that is open on a creeping surface of the paint spraying member is formed.

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