JP5736273B2 - Coating method and coating apparatus - Google Patents

Description

  The present invention relates to a coating method and a coating apparatus that perform electrostatic coating by spraying a liquid paint from a rotary atomizing head.

  2. Description of the Related Art A rotary atomizing coating device is known as a coating device for painting a car body and the like. The rotary atomizing coating apparatus rotates while applying a high voltage to the rotary atomizing head, and supplies a conductive paint (liquid paint) to the rotary atomizing head in this state. As a result, the liquid paint is charged and atomized, and sprayed from the leading edge of the rotary atomizing head to perform electrostatic coating.

  Moreover, in the rotary atomization type coating apparatus according to a conventional example, in order to reliably apply a paint to a workpiece (object to be coated) having a complicated shape, the rotary atomization is performed on the outer rear side of the rotary atomization head. An annular air outlet is provided concentrically with the rotational axis of the head, and the coating pattern diameter is changed by controlling the amount of air injection from the air outlet (see, for example, Patent Document 1 below). .

JP 2009-72703 A

  By the way, in carrying out the coating by the rotary atomizing type coating device, in general, in consideration of the coating efficiency, the coating gun is made to face the part to be coated of the work, that is, the rotary atomizing head constituting the coating gun is used. The paint is sprayed in a state where the rotation axis is arranged substantially perpendicular to the part to be coated.

  However, in the case of automobile inner panel coating, etc., in order to avoid the coating gun from interfering with the workpiece, the coating gun may be applied in a state where it is arranged not diagonally with respect to the part to be coated. is there. In this case, there is a problem that the coating efficiency is lowered because the end portion of the coating pattern with a small coating amount is used for overcoating.

  The present invention has been made in consideration of such problems, and even when coating is performed in a state where the coating gun is disposed obliquely with respect to the portion to be coated, a coating method and a coating that can be efficiently applied An object is to provide an apparatus.

In order to achieve the above object, the present invention provides a coating method for coating the workpiece by directing paint discharged from a rotating rotary atomizing head to the workpiece side with annular shaping air, wherein the shaping air A portion constituting a predetermined area in the circumferential direction is set as the first air, and is ejected at a relatively high wind speed, and in parallel with the ejection of the first air, another area in the circumferential direction is formed in the shaping air. The portion to be used is the second air, and is ejected at a wind speed relatively lower than that of the first air. The first air and the second air form the annular shaping air, and the first air side has the first air. by pulling the second air, said position displaced from the axis of rotation of the rotary atomizing head to form a coating pattern centered, the first air wind speed, 140% with respect to the second air wind speed It characterized in that it is a below.

  According to the above application method, the application pattern can be displaced toward the first air side of the early part by making the flow rate of a part of the shaping air ejected in an annular shape faster than the flow rate of the other part. As a result, it is possible to form a coating pattern centered on a position shifted from the rotational axis of the rotary atomizing head. Therefore, even when applying in a state where the rotation axis of the rotary atomizing head is not perpendicular to the part to be coated but inclined, it can be applied using a portion with a large amount of application in the application pattern, so it is efficient. Can be painted.

Further, by setting the wind speed as described above , the coating pattern can be uniformly applied without being broken.

In the above-described coating method, inner shaping air is jetted toward the outer peripheral edge of the rotary atomizing head inside the first air and the second air, and the wind speed of the first air is It should be faster than the speed of the shaping air . In this way, in addition to the ejection of the first air and the second air for controlling the center position of the coating pattern, the inside shaping toward the outer peripheral edge of the bell cup in the first air and the second air. Since air is ejected, the control of the center position of the coating pattern and the atomization of the paint can be carried out reliably and effectively.

In addition, the present invention is a coating apparatus including a rotary atomizing head that discharges paint to a workpiece, and an air ejection mechanism that ejects annular shaping air toward the outer peripheral edge of the rotary atomizing head. The air ejection mechanism includes a first air outlet that is a portion of the shaping air that constitutes a predetermined area in the circumferential direction and ejects a relatively high wind speed of the first air, and a peripheral portion of the shaping air. a portion constituting the other areas of direction have a second air ejection outlet for ejecting the second air relatively high wind speed, the annular of the shaping air by the second air and the first air Forming the second air to the first air side to form a coating pattern centered on a position shifted from the rotational axis of the rotary atomizing head, and the wind speed of the first air is For wind speed of 2 air Characterized in der Rukoto 140% or less.

According to the above coating apparatus, a coating pattern centered on a position deviated from the rotation axis of the rotary atomizing head can be formed, so that the axis of the rotary atomizing head is inclined rather than perpendicular to the portion to be coated. Even when applied, it can be applied efficiently. Further, by setting the wind speed as described above, the coating pattern can be uniformly applied without being broken.

  In the coating apparatus, the air ejection mechanism includes a plurality of buffer chambers divided in the circumferential direction, a first air supply hole that communicates at least one of the buffer chambers and the first air ejection port, and the remaining It is good to have the 2nd air supply hole which connects the said buffer chamber and the said 2nd air ejection port.

  With the above configuration, a relatively large flow rate of air is supplied to the buffer chamber corresponding to the first air ejection port, and a relatively small flow rate of air is supplied to the other buffer chamber corresponding to the second air ejection port. By doing so, it is possible to reliably eject shaping air having different wind speeds.

In the coating apparatus, the air ejection mechanism is configured to eject inner shaping air toward the outer peripheral edge of the rotary atomizing head inward of the first air ejection port and the second air ejection port. A jet port may be further provided , and the wind speed of the first air may be faster than the wind speed of the inner shaping air .

  According to the above configuration, in addition to the ejection of the first air and the second air for controlling the center position of the coating pattern, the outer periphery of the bell cup is inward of the first air and the second air. Since the inner shaping air is ejected toward the inside, the control of the center position of the coating pattern and the atomization of the paint can be carried out reliably and effectively.

  According to the coating method and the coating apparatus of the present invention, even when coating is performed in a state where the coating gun is disposed obliquely with respect to the portion to be coated, the coating can be efficiently performed.

1 is a schematic configuration diagram of a coating apparatus according to a first embodiment of the present invention. It is a perspective view which shows the back surface of the ring member of the coating device shown in FIG. FIG. 3A is a perspective view showing a body and a door of an automobile, and FIG. 3B is a schematic diagram showing the relationship between the position of the painting gun of the painting apparatus and the angle of the painting gun with respect to the part to be painted. It is a schematic diagram which shows the application pattern of the coating material discharged from the coating gun. FIG. 5A is a rear view of the ring member according to the first modification, and FIG. 5B is a rear view of the ring member according to the second modification. It is a schematic block diagram of the coating device which concerns on 2nd Embodiment of this invention. It is a cross-sectional view along the VII-VII line in FIG.

  Hereinafter, preferred embodiments of the coating method and the coating apparatus according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of a coating apparatus 10 according to the first embodiment of the present invention. As shown in FIG. 1, the coating apparatus 10 includes at least a coating gun 12 that constitutes the apparatus main body and an air supply system 14 that supplies air for shaping air 17 to the coating gun 12.

  The coating gun 12 includes a casing (housing) 16, an air motor 18 provided in the casing 16, a rotary shaft 20 having a hollow structure that is rotated at high speed by the air motor 18, and a pipe member 22 inserted through a hollow portion of the rotary shaft 20. And a bell-shaped rotary atomizing head 24 provided at the tip of the rotary shaft 20, and an air jet mechanism 26 that jets the shaping air 17 toward the outer periphery of the tip of the rotary atomizing head 24.

  The air motor 18 is configured to be supplied with compressed air from a compressed air source (not shown) and to rotate the rotating shaft 20 at a high speed. The rotary shaft 20 is connected to a high voltage generator (not shown) that generates a high voltage. Accordingly, a negative high voltage is applied to the rotary atomizing head 24 via the rotary shaft 20. The rotating shaft 20 is a member formed in a hollow cylindrical shape, and a tube member 22 is disposed in the hollow portion.

  A paint supply path 28 for flowing paint and a cleaning liquid supply path 30 for flowing cleaning liquid are formed in the tube member 22. The distal end portion of the tube member 22 is a double tube, and a paint supply nozzle 32 that discharges the paint and a cleaning liquid supply nozzle 34 that discharges the cleaning liquid are formed concentrically.

  The rotary atomizing head 24 is fixed to the tip of the rotary shaft 20, and when the rotary shaft 20 rotates under the action of the air motor 18, the rotary atomizing head 24 rotates together with the rotary shaft 20. In the rotary atomizing head 24, a paint reservoir 36 for temporarily storing the paint supplied via the pipe member 22 is formed. The paint reservoir 36 is a circular space. The paint supply nozzle 32 faces the center of the paint reservoir 36.

  The rotary atomizing head 24 is composed of an inner member 38 fixed to the rotary shaft 20 and a bell cup 40 fixed to the outer peripheral portion of the inner member 38, and between the inner member 38 and the bell cup 40. A paint reservoir 36 is formed. The inner member 38 is formed with a recess 38 a into which the tip of the rotary shaft 20 is fitted, and an opening through which the tip of the tube member 22 is inserted is formed at the center of the front surface of the inner member 38.

  The bell cup 40 is formed in a circular cup shape spreading outward in the radial direction toward the front. A paint discharge creeping surface 42 is formed on the front face of the bell cup 40 to thin the paint supplied to the front face. The coating material discharge creeping surface 42 is inclined forwardly outward in the radial direction, and is a donut-shaped surface in a front view. The coating material from the coating material reservoir 36 is thinned by a centrifugal force generated by the rotation of the bell cup 40.

  The bell cup 40 is provided with a plurality of paint supply holes 44 for supplying paint to the paint discharge creeping surface 42 at equal intervals in the circumferential direction around the rotation axis a of the rotary atomizing head 24. Each paint supply hole 44 is inclined toward the front of the rotary atomizing head 24 so as to be away from the axis a of the rotary atomizing head 24, and one end (inner end) is opened at the paint reservoir 36 and the other end ( The outer end) is open at the front surface of the bell cup 40.

  The central portion on the back side of the bell cup 40 protrudes toward the inside (the pipe member 22 side) of the paint reservoir 36 and distributes the supplied paint and cleaning liquid to the outside in the radial direction.

  A plurality of grooves 46 are formed at equal intervals in the circumferential direction on the front outer peripheral edge of the bell cup 40 (that is, the outer peripheral edge of the paint discharge creeping surface 42). The grooves 46 are provided at equal intervals in the circumferential direction over the entire circumference of the outer peripheral edge of the coating material discharge creeping surface 42, and extend along the radial direction of the rotary atomizing head 24. The thin film paint that has flowed radially outward is subdivided. Thereby, from the outer peripheral end of the bell cup 40, the paint (liquid yarn) in the form of a fine thread is released.

  Between the casing 16 and the air motor 18, a plurality (three in the illustrated example) of ring-shaped flow path forming members 50, 52 and 54 are arranged. Hereinafter, the flow path forming members 50, 52, and 54 are referred to as “first flow path forming member 50”, “second flow path forming member 52”, and “third flow path forming member 54”, respectively. The first flow path forming member 50 is disposed outside the air motor 18, and an annular recess 50 a is formed on the outer periphery thereof, and a plurality of flow paths 50 b penetrating in the axial direction are spaced apart in the circumferential direction. Formed.

  The second flow path forming member 52 is disposed between the first flow path forming member 50 and the casing 16, and a flow path 52a penetrating in the axial direction is formed. An annular space 51 is formed by the first flow path forming member 50, the second flow path forming member 52, and the casing 16. The third flow path forming member 54 is disposed between the casing 16 and the first flow path forming member 50 and in front of the first flow path forming member 50 and the second flow path forming member 52. In the third flow path forming member 54, a flow path 54a communicating with the flow path 52a of the second flow path forming member 52 and a flow path 54b communicating with the flow path 50b of the first flow path forming member 50 are formed. ing.

  A ring member 27 constituting the air ejection mechanism 26 is fixed to the tip of the third flow path forming member 54 concentrically with the bell cup 40 so as to surround the bell cup 40 on the back side of the bell cup 40. The shaping air 17 is ejected from the rear of the outer peripheral edge of the bell cup 40 toward the outer peripheral edge.

  FIG. 2 is a perspective view of the ring member 27 as seen from the back side. As shown in FIGS. 1 and 2, a first arcuate recess 60 and a second arcuate recess 62 are formed on the back surface of the ring member 27. The first arcuate recess 60 and the second arcuate recess 62 are partitioned by partition walls 64a and 64b and have substantially the same volume. An arc-shaped first buffer chamber 64 is formed by the first arc-shaped recess 60 and the front surface of the third flow path forming member 54. An arc-shaped second buffer chamber 66 is formed by the second arc-shaped recess 62 and the front surface of the third flow path forming member 54.

  The ring member 27 further includes a plurality of first air supply holes 68 that communicate between the first buffer chamber 64 and the front surface of the ring member 27, and a plurality of second air chambers that communicate between the second buffer chamber 66 and the front surface of the ring member 27. An air supply hole 70 is formed. The first air supply hole 68 has one end (rear end) opened at the first buffer chamber 64 and the other end (front end) opened as a first air jet outlet 68a on the front surface. The second air supply hole 70 has one end (rear end) opened at the second buffer chamber 66, and the other end (front end) opened as a second air jet outlet 70a on the front surface.

  The first air supply hole 68 and the second air supply hole 70 are provided at equal intervals in the circumferential direction centering on the axis a, and are inclined so as to approach the axis a of the rotary atomizing head 24 toward the front. And it opens toward the outer peripheral edge of the bell cup 40. Further, the first air supply hole 68 and the second air supply hole 70 are arranged at a predetermined angle (for example, 30 degrees to 50 degrees) with respect to the direction of the axis a in the circumferential direction around the axis a of the rotary atomizing head 24. ) Inclined.

  In the coating gun 12 shown in FIG. 1, the annular space 51, the flow path 52a of the second flow path forming member 52, the flow path 54a of the third flow path forming member 54, the first buffer chamber 64, and the first air supply hole. 68 constitutes a first air supply path 72. The second air supply path 74 is configured by the flow path 50b of the first flow path forming member 50, the flow path 54b of the third flow path forming member 54, the second buffer chamber 66, and the second air supply hole 70 described above. Has been.

  As shown in FIG. 1, the air supply system 14 includes an air source 80, and a first air line 82 and a second air line 84 that guide the compressed air from the air source 80 to the coating gun 12. The air source 80 is an air pump, for example, and sends out compressed air. The first air line 82 supplies compressed air to the annular space 51.

  A first flow meter 88 and a first electropneumatic converter 86 are disposed on the first air line 82. The first air control unit 90 uses the flow value detected by the first flow meter 88 as a feedback value, and the flow rate of air supplied to the first air supply path 72 is a predetermined flow rate (hereinafter referred to as “first flow rate”). The 1st electropneumatic converter 86 is controlled so that it may become.

  A second flow meter 94 and a second electropneumatic converter 92 are disposed on the second air line 84. The second air control unit 96 uses the flow rate value detected by the second flow meter 94 as a feedback value, and the flow rate of air supplied to the second air supply path 74 is a predetermined flow rate (hereinafter referred to as “second flow rate”). The 2nd electropneumatic converter 92 is controlled so that it may become.

  The compressed air supplied to the coating gun 12 by the first air line 82 of the air supply system 14 passes through the annular space 51, the flow path 52a, the flow path 54a, the first buffer chamber 64, and the first air supply hole 68 in this order. The first air 17a is ejected from the first air ejection port 68a. The compressed air supplied to the coating gun 12 by the second air line 84 of the air supply system 14 passes through the flow path 50b, the flow path 54b, the second buffer chamber 66, and the second air supply hole 70 in order, It is ejected as the second air 17b from the 2-air jet outlet 70a.

  In the coating apparatus 10, the first air 17 a ejected from the first air ejection port 68 a is a portion constituting a predetermined area in the circumferential direction of the shaping air 17 and has a relatively high wind speed. The 2nd air 17b ejected from the 2nd air ejection port 70a is a part which comprises the other area of the circumferential direction among the shaping air 17, Comprising: It is a relatively low wind speed. That is, the wind speed (flow velocity) of the first air 17a is higher than the wind speed (flow velocity) of the second air 17b. For this reason, the first flow rate controlled by the first electropneumatic converter 86 is set larger than the second flow rate controlled by the second electropneumatic converter 92.

  The coating apparatus 10 according to the present embodiment is basically configured as described above, and the operation and effect thereof will be described below.

  When painting, the rotary shaft 20 is rotated at high speed by the air motor 18. Then, the paint is discharged from the paint supply nozzle 32 toward the paint reservoir 36 of the rotary atomizing head 24. As a result, the paint that has flowed into the paint reservoir 36 flows into the paint supply hole 44. In this case, the paint that has passed through the paint supply hole 44 flows out to the paint discharge creeping surface 42, where it is thinned and then subdivided by the groove 46 and jumps out from the outer peripheral end of the bell cup 40 as liquid yarn. The liquid yarn discharged from the outer peripheral end of the bell cup 40 is atomized as paint particles.

  At this time, since a high voltage is applied between the rotary atomizing head 24 and the work (object to be coated), the charged paint particles atomized by the rotary atomizing head 24 fly toward the work. Apply to work. The spray pattern of the paint at this time is shaped by the shaping air 17 (first air 17a and second air 17b) ejected from the first air ejection port 68a and the second air ejection port 70a.

  By the way, for example, as shown in FIG. 3A, a case is assumed in which painting is performed on a door inner plate 104 in the vicinity of a connecting portion between a body 100 and a door 102 of an automobile. In this case, as shown in FIG. 3B, the coating gun 12 interferes with the door 102 even if the coating gun 12 is arranged in a plane with respect to the portion to be painted (door inner plate 104) in order to efficiently paint. Therefore, the paint gun 12 cannot be arranged in that way. For this reason, it may be necessary to apply the paint gun 12 in an obliquely arranged state, like the paint gun 12 shown by a solid line in FIG. 3B.

  In this case, in the coating apparatus 10 according to the present invention, the first air 17a having a relatively high wind speed is ejected from the first air ejection port 68a, and the second air having a relatively low wind speed is ejected from the second air ejection port 70a. 17b is ejected. As described above, when the flow velocity of a part (first air 17a) of the shaping air 17 ejected in an annular shape is made faster than the flow velocity of the other part (second air 17b), the pressure of the first air 17a is changed to the second air 17b. Therefore, as shown in FIG. 4, the second air 17b is attracted to the first air 17a side. As a result, it is possible to form a coating pattern having a center c at a position shifted from the axis a of the rotary atomizing head 24. Therefore, even when applying in a state where the axis a of the rotary atomizing head 24 is inclined rather than perpendicular to the part to be coated, it can be applied using a portion with a large amount of application in the application pattern. It can be painted efficiently.

  Table 1 below shows the test results on how the coating pattern is formed when the wind speed ratio between the first air 17a and the second air 17b is changed under the following coating conditions. . In Table 1, “first air wind speed” and “second air wind speed” are the wind speeds of the first air 17 a and the second air 17 b at the outer peripheral edge of the bell cup 40. The “wind speed ratio” is a percentage of the wind speed of the first air 17a with respect to the wind speed of the second air 17b. The “deviation amount from the center” is the deviation amount of the center c of the coating pattern from the axis a of the rotary atomizing head 24.

(Painting conditions)
Number of revolutions (rpm): 35000
Discharge amount (cc / min): 290
Discharge time (sec): 0.6
Painting distance (mm): 250
Applied voltage (kV): -60

  From Table 1, it can be seen that as the wind speed of the first air 17a with respect to the second air 17b is increased, the deviation amount of the center of the coating pattern is increased. On the other hand, it was found that if the wind speed ratio is increased too much, dividing lines (parts where no paint is applied) are formed in a part of the application pattern. In the results shown in Table 1, no split line was generated when the wind speed ratio was 137%, and split lines were generated when the wind speed ratio was 179%. Therefore, the wind speed of the first air 17a may be 140% or less with respect to the wind speed of the second air 17b. By setting the wind speed in this way, the coating pattern can be uniformly applied without being broken.

  The first air jet port 68a described above is configured by a large number of holes arranged at intervals in the circumferential direction in the ring member 27. Instead of such a configuration, an arc shape extending in the circumferential direction is formed. It may be constituted by a hole (slit). Similarly, the second air ejection port 70a is configured by a large number of holes arranged at intervals in the circumferential direction in the ring member 27, but instead of such a configuration, a circle extending in the circumferential direction is formed. You may be comprised by the arc-shaped hole (slit).

  The ring member 27 described above has a configuration in which two arc-shaped concave portions (the first arc-shaped concave portion 60 and the second arc-shaped concave portion 62) are provided, but a configuration in which three or more arc-shaped concave portions are provided is adopted. Also good. For example, in the coating apparatus 10 described above, instead of the ring member 27 having the first arc-shaped recess 60 and the second arc-shaped recess 62, the ring member 110 having four arc-shaped recesses 112a to 112d (see FIG. 5A). Or the ring member 120 (refer FIG. 5B) which has eight circular arc-shaped recessed parts 122a-122h may be employ | adopted.

  When the ring member 110 shown in FIG. 5A is used, the first air 17a (see FIG. 1) having a relatively high wind speed is ejected from the plurality of air supply holes 113a provided in the arc-shaped recess 112a, and the other arc-shaped The relatively low wind speed second air 17b (see FIG. 1) is ejected from the plurality of air supply holes 113b to 113d provided in the recesses 112b to 112d. Thereby, the shift | offset | difference direction of the center c of an application | coating pattern can be controlled more correctly.

  The first air 17a is ejected from any two of the four arcuate recesses 112a to 112d, for example, the air supply holes 113a and 113b provided in the arcuate recesses 112a and 112b, and the other arcuate recesses 112c, The second air 17b may be ejected from the air supply holes 113c and 113d provided in 112d. In this case, a coating pattern similar to that when the ring member 27 shown in FIGS. 1 and 2 is employed is formed.

  When the ring member 120 shown in FIG. 5B is used, the first air 17a having a relatively high wind speed is ejected from the air supply hole 123a provided in the arc-shaped recess 122a, and is provided in the other arc-shaped recesses 122b to 122h. The second air 17b having a relatively low wind speed is ejected from the air supply holes 123b to 123h. Thereby, the shift | offset | difference direction of the center c of an application | coating pattern can be controlled more correctly.

  The first air 17a is ejected from any two to four of the eight arcuate recesses 122a to 122h, for example, the air supply holes 123a to 123c provided in the arcuate recesses 122a to 122c, and the other arcuate shapes. The second air 17b may be ejected from the air supply holes 123d to 123h provided in the recesses 122d to 122h. When the first air 17a is ejected from the air supply holes 123a to 123d of the arc-shaped recesses 122a to 122d, a coating pattern similar to that when the ring member 27 shown in FIGS. 1 and 2 is employed is formed.

  FIG. 6 is a schematic configuration diagram of a coating apparatus 10a according to the second embodiment of the present invention. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6 (however, illustration of the rotary atomizing head 24 is omitted). In addition, in the coating apparatus 10a which concerns on 2nd Embodiment, the same referential mark is attached | subjected to the element which show | plays the same or similar function and effect as the coating apparatus 10 which concerns on 1st Embodiment, and detailed description is abbreviate | omitted.

  In the coating gun 130 constituting the main body of the coating apparatus 10a, a plurality (three in the illustrated example) of ring-shaped flow path forming members 132, 134, 136 are disposed between the casing 16 and the air motor 18. . Hereinafter, the flow path forming members 132, 134, and 136 are referred to as “first flow path forming member 132”, “second flow path forming member 134”, and “third flow path forming member 136”, respectively.

  The first flow path forming member 132 is disposed outside the air motor 18, and concave portions 132 a and 132 b are formed in the outer peripheral portion thereof, and a plurality of flow paths 132 c penetrating in the axial direction are spaced apart in the circumferential direction. Formed. The second flow path forming member 134 is disposed between the first flow path forming member 132 and the casing 16, and a plurality of flow paths 134a and 134b penetrating in the axial direction are formed. The first flow path forming member 132, the second flow path forming member 134, and the casing 16 form mutually independent spaces 131a and 131b.

  The third flow path forming member 136 is disposed between the casing 16 and the first flow path forming member 132 and in front of the first flow path forming member 132 and the second flow path forming member 134. The third flow path forming member 136 includes a flow path 136a communicating with one flow path 134a of the second flow path forming member 134 and a flow path 136b communicating with the other flow path 134b of the second flow path forming member 134. In addition, a plurality of flow paths 136c communicating with the flow path 132b of the first flow path forming member 132 are formed. Between the second flow path forming member 134 and the third flow path forming member 136, two spaces 133a and 133b that are airtightly partitioned by a partition wall (not shown) are formed.

  A ring member 140 constituting the air ejection mechanism 138 is fixed to the tip of the third flow path forming member 136 concentrically with the rotary atomizing head 24 so as to surround the bell cup 40 on the back side of the bell cup 40. The annular shaping air 17 is ejected from the rear of the outer peripheral edge of the bell cup 40 toward the outer peripheral edge.

  A first arc-shaped recess 142, a second arc-shaped recess 144, and an annular recess 146 are formed on the back surface of the ring member 140. The first arcuate recess 142 and the second arcuate recess 144 are partitioned by partition walls 148a and 148b (see FIG. 7) and have substantially the same volume. The annular recess 146 is formed radially inward of the first arc-shaped recess 142 and the second arc-shaped recess 144.

  An arc-shaped first buffer chamber 150 is formed by the first arc-shaped recess 142 and the front surface of the third flow path forming member 136. An arc-shaped second buffer chamber 152 is formed by the second arc-shaped recess 144 and the front surface of the third flow path forming member 136. An annular third buffer chamber 154 is formed by the annular recess 146 and the front surface of the third flow path forming member 136.

  The ring member 140 further includes a plurality of first air supply holes 156 that communicate between the first buffer chamber 150 and the front surface of the ring member 140, and a plurality of second air chambers that communicate between the second buffer chamber 152 and the front surface of the ring member 140. An air supply hole 158 and a plurality of third air supply holes 160 communicating with the third buffer chamber 154 and the front surface of the ring member 140 are formed.

  The first air supply holes 156 are provided at equal intervals in the circumferential direction around the axis a, one end (rear end) is opened in the first buffer chamber 150, and the other end (front end) is the front surface with the first air. It opens as a spout 156a. The second air supply holes 158 are provided at equal intervals in the circumferential direction around the axis a, one end (rear end) is opened in the second buffer chamber 152, and the other end (front end) is the front surface with the second air. It opens as a spout 158a. The third air supply holes 160 are provided at equal intervals in the circumferential direction about the axis a, one end (rear end) is opened by the third buffer chamber 154, and the other end (front end) is the front surface with the third air. It opens as a spout (inner air spout) 160a.

  The first air supply hole 156 and the second air supply hole 158 are provided on the same circumference, are provided at equal intervals in the circumferential direction, and approach the axis a of the rotary atomizing head 24 toward the front. Slightly tilted. The third air supply holes 160 are provided at equal intervals in the circumferential direction inside the first air supply holes 156 and the second air supply holes 158 so as to approach the axis a of the rotary atomizing head 24 toward the front. And is open toward the outer peripheral edge of the bell cup 40.

  The first air supply hole 156, the second air supply hole 158, and the third air supply hole 160 are arranged at a predetermined angle with respect to the axis a direction in the circumferential direction around the axis a of the rotary atomizing head 24 ( For example, it is inclined 30 to 50 degrees).

  In the coating gun 130 shown in FIG. 6, the above-described space 131a, one flow path 134a of the second flow path forming member 134, the flow path 136a of the third flow path forming member 136, the first buffer chamber 150, and the first air supply A first air supply path 162 is configured by the hole 156. The second air supply path 164 is configured by the other flow path 134b of the second flow path forming member 134, the flow path 136b of the third flow path forming member 136, the second buffer chamber 152, and the second air supply hole 158. Has been. A third air supply path 166 is formed by the flow path 132 c of the first flow path forming member 132, the flow path 136 c of the third flow path forming member 136, the third buffer chamber 154, and the third air supply hole 160.

  The air supply system 170 is obtained by adding a third air line 172, a third flow meter 176, a third electropneumatic converter 174, and a third air control unit 178 to the air supply system 14 shown in FIG. is there. The third flow meter 176 and the third electropneumatic converter 174 are disposed on the third air line 172, and the third air control unit 178 uses the flow value detected by the third flow meter 176 as a feedback value, The third electropneumatic converter 174 is controlled so that the flow rate of the air supplied to the air supply path 166 becomes a predetermined flow rate.

  The compressed air supplied to the coating gun 130 by the first air line 82 passes through the first air supply path 162 and is ejected from the first air ejection port 156a as the first air 17a. The compressed air supplied to the coating gun 130 by the second air line 84 passes through the second air supply path 164 and is ejected as the second air 17b from the second air ejection port 158a. The compressed air supplied to the coating gun 130 by the third air line 172 passes through the third air supply path 166 and is ejected as the annular inner shaping air 19 from the third air ejection port 160a.

  In the coating apparatus 10a, the first air 17a ejected from the first air ejection port 156a is a portion constituting a predetermined area in the circumferential direction of the shaping air 17, and has a relatively high wind speed. The second air 17b ejected from the second air ejection port 158a is a portion constituting another area in the circumferential direction of the shaping air 17 and has a relatively low wind speed. That is, the wind speed (flow velocity) of the first air 17a is higher than the wind speed (flow velocity) of the second air 17b. For this reason, the first flow rate controlled by the first electropneumatic converter 86 is set larger than the second flow rate controlled by the second electropneumatic converter 92.

  When coating is performed by the coating apparatus 10a configured as described above, the rotating shaft 20 is rotated at a high speed by the air motor 18, and the paint is applied from the paint supply nozzle 32 toward the paint reservoir 36 of the rotary atomizing head 24. Discharge. Then, after the coating material is thinned along the coating material discharge surface, the coating material is subdivided by the grooves 46 and ejected from the outer peripheral end of the bell cup 40 as a liquid thread to be atomized as coating particles. At this time, since the inner shaping air 19 is ejected from the third air ejection port 160 a toward the outer peripheral edge of the bell cup 40, atomization of the paint is promoted by the inner shaping air 19. The atomized charged paint particles fly toward the workpiece and are applied to the workpiece. The spray pattern of the paint at this time includes the inner shaping air 19 ejected from the third air ejection port 160a, and the shaping air 17 (first air 17a ejected from the first air ejection port 156a and the second air ejection port 158a. And the second air 17b).

  As described above, according to the coating apparatus 10a according to the present embodiment, the first air 17a having a relatively high wind speed is ejected from the first air ejection port 156a, and the first air ejection port 158a is relatively ejected. Since the second air 17b having a low wind speed is ejected, an application pattern having a center c as a position shifted from the axis a of the rotary atomizing head 24 can be formed, as in the coating apparatus 10 according to the first embodiment. Therefore, even when applying in a state where the axis a of the rotary atomizing head 24 is inclined rather than perpendicular to the part to be coated, it can be applied using a portion with a large amount of application in the application pattern. It can be painted efficiently.

  In the case of this embodiment, in addition to the first air 17a and the second air 17b for controlling the center position of the coating pattern, the outer peripheral edge of the bell cup 40 inside the first air 17a and the second air 17b. Since the inner shaping air 19 is ejected toward the portion, the control of the center position of the coating pattern and the atomization of the paint can be carried out reliably and effectively. That is, the inner shaping air 19 has a function of atomizing the paint, and the first air 17a and the second air 17b have a function of displacing the center c of the coating pattern, so that each function is effectively exhibited. be able to.

  In this case, by setting the wind speed of the first air 17a faster than the wind speed of the inner shaping air 19, the inner shaping air 19 is effectively moved toward the first air 17a by the first air 17a having a relatively high wind speed. As a result, the control of the center position of the coating pattern can be performed more reliably. For example, the wind speed of the first air 17 a is preferably 150% or more with respect to the wind speed of the inner shaping air 19.

  The first air outlet 156a in the illustrated example is configured by a large number of holes arranged at intervals in the circumferential direction in the ring member 140, but instead of such a configuration, a circle extending in the circumferential direction is formed. You may be comprised by the arc-shaped hole (slit). Similarly, the second air outlet 158a in the illustrated example is configured by a number of holes arranged at intervals in the circumferential direction in the ring member 140, but instead of such a configuration, it extends in the circumferential direction. It may be configured by existing arc-shaped holes (slits).

  The third air outlet 160a in the illustrated example is configured by a large number of holes arranged at intervals in the circumferential direction in the ring member 140, but instead of such a configuration, a ring extending in the circumferential direction is provided. It may be configured by a shape hole (slit).

  The ring member 140 described above has a configuration in which two arc-shaped concave portions (a first arc-shaped concave portion 142 and a second arc-shaped concave portion 144) are provided, and follows the ring members 110 and 120 shown in FIGS. 5A and 5B. A configuration in which three or more arc-shaped concave portions are provided may be employed.

  In addition, in the second embodiment, for each component common to the first embodiment, it is possible to obtain the same or similar operation and effect as the operation and effect brought about by the common component in the first embodiment. Of course.

  In the above description, the present invention has been described with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Yes.

DESCRIPTION OF SYMBOLS 10, 10a ... Coating apparatus 17 ... Shaping air 17a ... 1st air 17b ... 2nd air 19 ... Inner shaping air 24 ... Rotating atomizing head 26 ... Air jet mechanism 64, 150 ... 1st buffer chamber 66, 152 ... 2nd Buffer chambers 68, 156: first air supply holes 68a, 156a ... first air outlets 70, 158: second air supply holes 70a, 158a ... second air outlets 160a ... third air outlets

Claims (5)

A coating method of coating the workpiece by directing the paint discharged from the rotating rotary atomizing head to the workpiece side by annular shaping air,
A portion of the shaping air that constitutes a predetermined area in the circumferential direction is the first air, and is ejected at a relatively high wind speed.
In parallel with the ejection of the first air, the portion constituting the other area in the circumferential direction of the shaping air is used as the second air, and is ejected at a lower wind speed than the first air.
An annular shaping air is formed by the first air and the second air, and the second air is attracted to the first air side, thereby centering on a position shifted from the rotation axis of the rotary atomizing head. Form a coating pattern ,
The wind speed of the first air is 140% or less with respect to the wind speed of the second air.
A painting method characterized by that. In the coating method of claim 1 Symbol placement,
Inward of the first air and the second air, the inner shaping air is ejected toward the outer peripheral edge of the rotary atomizing head ,
The wind speed of the first air is faster than the wind speed of the inner shaping air.
A painting method characterized by that. A rotary atomizing head that discharges paint onto the workpiece;
A coating apparatus comprising an air ejection mechanism that ejects annular shaping air toward the outer peripheral edge of the rotary atomizing head,
The air ejection mechanism is
A first air outlet that is a portion of the shaping air that constitutes a predetermined area in the circumferential direction and that ejects a relatively high wind speed of the first air;
Wherein a portion constituting the other areas in the circumferential direction of the shaping air have a second air ejection outlet for ejecting the second air relatively high wind speed,
An annular shaping air is formed by the first air and the second air, and the second air is attracted to the first air side, thereby centering on a position shifted from the rotation axis of the rotary atomizing head. Form a coating pattern ,
The wind speed of the first air is 140% or less with respect to the wind speed of the second air .
A painting device characterized by that. The coating apparatus according to claim 3 ,
The air ejection mechanism, the inside of the first air ejection outlet and the second air ejection port, further Bei example inside air ejection ports for ejecting an inner shaping air toward the outer peripheral edge of said rotary atomizing head ,
The wind speed of the first air is faster than the wind speed of the inner shaping air.
A painting device characterized by that. In the coating device according to claim 3 or 4,
The air ejection mechanism includes a plurality of buffer chambers divided in a circumferential direction, a first air supply hole communicating at least one of the buffer chambers and the first air ejection port, the remaining buffer chambers, and the first A second air supply hole that communicates with the two air outlets;
A painting device characterized by that.

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