Patent Publication Number: US-2019176181-A1

Title: Painting booth

Description:
TECHNICAL FIELD 
     The present invention relates to a painting booth which has, in the inside thereof, a painting treatment area where a workpiece is coated with atomized paint, and in which air flows down from an air supply unit provided at the upper part of the inside so as to remove atomized paint not attached to the workpiece. 
     BACKGROUND ART 
     As a painting booth of this type, there is conventionally known a painting booth in which an entire ceiling is configured with a mesh and a filter mat stacked on the mesh, and air flows downward in the vertical direction from the entire ceiling while the ceiling space is pressurized (for example, see Patent Document 1). 
     RELATED ART DOCUMENTS 
     Patent Documents 
     Patent Document 1: Japanese Patent Application Laid-Open No. H8-266988 (FIGS. 1 to 3) 
     SUMMARY OF INVENTION 
     Problems to be Solved by the Invention 
     Meanwhile, a coating gun used in a painting booth has a structure in which air called shaping air is blown out so as to atomize paint. In recent years, electrostatic coating guns have been improved to reduce a blowing pressure of the shaping air. In contrast, if a flowing speed of the air flowing down in the painting booth is the same as before, the atomized paint sprayed from the coating gun is blown away downward before attaching to a workpiece. To address this issue, the flow rate of the air flowing down in the painting booth is also reduced in order to reduce the flowing speed of the air. However, there is a problem that when the flow rate of the air is simply reduced in the conventional painting booth, an internal pressure in the ceiling space becomes too low to stably control the flow rate of the air flowing down in the painting booth. 
     The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a painting booth in which the flow rate of air flowing down in a painting booth can be stably controlled. 
     Means of Solving the Problems 
     In order to achieve the above object, a painting booth according to the present invention is a painting booth having therein a painting treatment area where a workpiece is painted with atomized paint, in which air flows down from an upper part of an inside of the painting booth to remove the atomized paint that is not attached to the workpiece. The painting booth includes a pair of first inner surfaces facing each other in a first horizontal direction with the painting treatment area therebetween, an air supply unit arranged at a center, in the first horizontal direction, of the upper part of the inside, and an air blow-out unit which is formed ranging from a central part to both side parts, in the first horizontal direction, of the air supply unit and which blows out air right downward at the central part and blows out the air in an obliquely downward direction of each of the first inner surfaces on the both side parts. 
     Further, a painting booth according to the present invention is a painting booth having therein a painting treatment area where a workpiece is painted with atomized paint, in which air flows down from an upper part of an inside of the painting booth to remove the atomized paint that is not attached to the workpiece. The painting booth includes: a side-part surrounding wall which has a cylindrical shape and laterally surrounds the painting treatment area; an air supply unit arranged at a central part of the upper part of the inside; and an air blow-out unit which is formed on the air supply unit and blows out air right downward at a center of the air supply unit, a blowing direction of air being more inclined toward a side of the side-part surrounding wall as being more distant sideward from the center of the air supply unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a painting booth according to a first embodiment of the present invention; 
         FIG. 2  is a sectional side view of the painting booth at an intermediate position in a longitudinal direction; 
         FIG. 3  is a sectional side view of the painting booth at an intermediate position in a transverse direction; 
         FIG. 4  is a perspective view of an air supply duct; 
         FIG. 5  is a partially enlarged sectional side view of an air supply unit; 
         FIG. 6  is a perspective view of a painting booth according to a second embodiment; 
         FIG. 7  is a sectional side view of a painting booth according to a modified example of the present invention; 
         FIG. 8  is a partially enlarged sectional side view of an air supply unit according to a modified example of the present invention; and 
         FIG. 9  is a sectional side view of a painting booth according to a modified example of the present invention. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     First Embodiment 
     Hereinafter, an embodiment of the present invention will be described with reference to  FIGS. 1 to 5 . As shown in  FIG. 1 , a painting booth  10  of the present embodiment has a rectangular planar shape. The transverse direction of the rectangle is a first horizontal direction H 1  according to the present invention, and the longitudinal direction of the rectangle is a second horizontal direction H 2  according to the present invention. In each of a pair of shorter-side side walls  11  facing each other in the second horizontal direction H 2  (longitudinal direction) in the painting booth  10 , each of carry-in/out ports  11 A and  11 A is formed. Further, a conveyance passage  12  shown in  FIG. 2  passes through the both carry-in/out ports  11 A and  11 A, and a conveyor carriage  13  carrying a workpiece W such as a vehicle body moves in one direction on the conveyance passage  12  and passes inside the painting booth  10 . 
     On an upper opening edge of each carry-in/out port  11 A in the painting booth  10 , an air curtain generator  11 B (see  FIG. 3 ) having, for example, a plurality of air nozzles laterally arranged is attached, so that the carry-in/out port  11 A is covered by an air curtain. 
     As shown in  FIG. 2 , duckboards  20  are provided on the both sides of the conveyance passage  12  in the painting booth  10 . On the duckboards  20 , a plurality of support platforms  14 A,  14 B, and  14 C having different sizes of large, medium, and small are provided as shown in  FIG. 3 . A coating robot  15  is mounted on each of the support platforms  14 A,  14 B, and  14 C, and the workpiece W is painted in a painting treatment area R 1  surrounded by the group of coating robots  15 . 
     Specifically, the support platforms  14 A,  14 B, and  14 C each have, for example, a pillar shape extending straight in the vertical direction, and are arranged at intervals in the second horizontal direction H 2  while being adjacent to a pair of longer-side side walls  30  and  30  of the painting booth  10  in the first horizontal direction H 1  as shown in  FIG. 2 . Further, each coating robot  15  is a so-called vertical articulated robot and is serially equipped with a first arm, a second arm, and a wrist on a horizontally rotatable pivot base. An electrostatic coating gun  16  is mounted on the top end part of the wrist. The coating gun  16  has the same structure as, for example, one disclosed in Japanese Patent Application Laid-Open No. 2013-166113 and sprays atomized paint in a charged state so that the atomized paint is attached to the workpiece W by using attraction force of static electricity. 
     An underfloor room  21  is formed below the duckboards  20 , and further below the underfloor room  21 , a suction room  23  which is separated from the underfloor room  21  by an underfloor separation plate  22  is formed. Further, a plurality of communication holes  24  are formed in the both side parts, in the first horizontal direction H 1 , of the underfloor separation plate  22 , and an annular ridge  24 A protrudes upward from the opening edge of each of the communication holes  24 . Then, air is suctioned through an exhaust duct  25  communicated to the suction room  23  while water is reserved on the upper surface of the underfloor separation plate  22 , up to the height of the annular ridge  24 A. A flow rate of the air being suctioned is approximately the same as the flow rate of air blown out into the painting booth  10  from an air supply duct  32  which will be described later. 
     As shown in  FIG. 2 , an upper part of the inside of the painting booth  10  is configured to have the air supply duct  32 , which corresponds to an “air supply unit” of the present invention, between a pair of inclined roofs  31  and  31 . The pair of inclined roofs  31  and  31  each have a flat plate shape and are inclined such that the inclined roofs  31  and  31  are raised from the upper end parts of the pair of longer-side side walls  30  and  30  toward the position close to the center, in the first horizontal direction H 1 , of the painting booth  10 . Further, a pair of first inclined ceiling surfaces  31 A and  31 A of the present invention and a pair of first inner surfaces  30 A and  30 A of the present invention intersect each other at an angle of, for example, approximately 45 degrees. The first inclined ceiling surfaces  31 A and  31 A are inner surfaces of the pair of inclined roofs  31  and  31 , and the first inner surfaces  30 A and  30 A are inner surfaces of the pair of longer-side side walls  30  and  30 . 
     A cross-section of the air supply duct  32  has a shape in which the lower side of a horizontally elongated rectangle is swollen downward in a semicircular shape. That is, the air supply duct  32  is structured to have a semicircular arc part  33  (corresponding to a “bay-shaped duct wall” of the present invention) under the rectangular part  34  of a horizontally elongated rectangular shape. Further, a boundary part between the rectangular part  34  and the semicircular arc part  33  is just positioned at, for example, the upper end parts of the inclined roofs  31  and  31 . The semicircular arc part  33  is projected downward in the painting booth  10 , and the rectangular part  34  is projected above the painting booth  10 . 
     As shown in  FIG. 4 , a plurality of communication ports  33 A are formed in an entire part of the semicircular arc part  33 . Specifically, for example, the semicircular arc part  33  is provided with the rectangular communication ports  33 A formed arranged in the circumferential direction of the semicircular arc part  33  and the longitudinal direction of the semicircular arc part  33 . Thus, the entire semicircular arc part  33  has a structure in which a plurality of longitudinal belt parts  33 B extending in the second horizontal direction H 2  are arranged in the circumferential direction of the semicircular arc part  33  and are connected by a plurality of lateral belt parts  33 C extending in the circumferential direction of the semicircular arc part  33 . Further, as shown in  FIG. 5 , a mesh  38  is laid on the entire part of the inner surface of the semicircular arc part  33 , and on the inside of the mesh  38 , a filter mat  39  is laid in an overlapping manner, so that approximately whole of the semicircular arc part  33  serves as an air blow-out unit  36  according to the present invention. 
     In the present embodiment, an “air-permeable pressure reduction member” according to the present invention is configured with the mesh  38  and the filter mat  39 . 
     Further, as shown in  FIG. 1 , an introduction part  35  is provided approximately at the center, in the longitudinal direction, of one side surface of the rectangular part  34 , and an air conditioner (not shown) is connected to the introduction part  35 . The air conditioner conditions air, in which external air is mixed with air suctioned through the exhaust duct  25  described above, to a predetermined humidity and temperature through heating, cooling, humidifying, or other treatments, and then feeds the air to the rectangular part  34 . 
     The configuration of the painting booth  10  of the present embodiment is described above. Next, an operation and effect of the painting booth  10  will be described. When the painting booth  10  is made to operate, compressed air is fed from the air conditioner to the air supply duct  32  corresponding to an “air supply unit” of the present invention, and thus an internal pressure of the air supply duct  32  is increased, whereby air is blown out from the entire air blow-out unit  36 , which is a lower side semicircular part of the air supply duct  32 , at a flow rate corresponding to the internal pressure. 
     In this operation, the air is blown out in the direction where the air blow-out unit  36  receives the internal pressure, in other words, in the normal vector direction at each position of the air blow-out unit  36 . Further, since the air blow-out unit  36  has a circular arc shape, a blowing direction of the air is vertically downward at the center, in the width direction, of the air blow-out unit  36  (also at the center, in the width direction, of the air supply duct  32 ), and the angle, in the blowing direction, of the air becomes gradually larger as being more distant from the center in the width direction toward the side. This enables the air to flow down from the air blow-out unit  36  in a radial manner, and it is possible to prevent or reduce generation of a windless area in the painting treatment area R 1 . The air is eventually suctioned down below the duckboards  20 . 
     Further, the air blown out sideward from the both side parts of the air blow-out unit  36  flows obliquely downward while being guided by the first inclined ceiling surfaces  31 A as shown in  FIG. 5 , and reaches the first inner surfaces  30 A, which are the inner surfaces of the longer-side side walls  30 , as shown in  FIG. 2  to be directed downward in the vertical direction. Then, the air passes around the coating robots  15  and the support platforms  14 A,  14 B, and  14 C, and is suctioned down below the duckboards  20 . By this operation, the atomized paint around the coating robots  15  and the support platforms  14 A,  14 B, and  14 C is reliably suctioned down below the duckboards  20 , and the paint is prevented from attaching to the first inner surfaces  30 A. 
     In the painting booth  10  of the present embodiment, the air supply duct  32  corresponding to the “air supply unit” of the present invention is arranged on a part (center) of the upper part of the inside, not on the entire upper part of the inside. Thus, the air supply unit, in other words, the capacity of the inside of the air supply duct  32  can be smaller than the conventional painting booth in which the entire upper part of the inside is the air supply unit. With this, even if the flow rate of the air flowing down in the painting booth  10  from the air blow-out unit  36  is made smaller, the internal pressure in the air supply duct  32  does not excessively decrease like before, whereby it is possible to stably control the flow rate of air. That is, it is possible to make air stably flow at such a flow speed that the air flow does not prevent atomized paint from attaching to a workpiece, and high-quality painting can be achieved by a coating gun  16  having a relatively low blowing pressure of shaping air. 
     Second Embodiment 
     A painting booth  10 V of the present embodiment is shown in  FIG. 6  and is configured to be equipped with a conical ceiling wall  41  of a conical shape on the upper side of a side-part surrounding wall  40  of a cylindrical shape, and is equipped with an air supply duct  42  at the central part of the conical ceiling wall  41 . The air supply duct  42  is configured such that a hemispherical body  43  (corresponding to a “container-shaped curved wall” of the present invention) is connected to the lower end part of a cylindrical body  44 . For example, a boundary part between the cylindrical body  44  and the hemispherical body  43  is fit in the upper end part of the conical ceiling wall  41 . An introduction part  45  is formed in the cylindrical body  44 , and an air conditioner (not shown) is connected to the introduction part  45 . In the hemispherical body  43 , a plurality of communication ports  43 A are perforated. The communication ports  43 A are covered by a mesh and filter mat (not shown), so that the whole of the hemispherical body  43  serves as an air blow-out unit  46  according to the present invention, and air flows down in a radial manner. 
     Also in the painting booth  10 V of the present embodiment, the air supply duct  42  serving as the “air supply unit” of the present invention is arranged on a part of the upper part of the inside. Thus, the capacity of the inside of the air supply unit can be smaller than the conventional painting booth in which the entire upper part of the inside serves as the air supply unit. With this arrangement, even if the flow rate of the air flowing down in the painting booth  10 V from the air blow-out unit  46  is made smaller, the internal pressure of the air supply duct  42  does not excessively decrease like before, whereby it is possible to stably control the flow rate of air. That is, it is possible to make air stably flow at such a flow speed that the air flow does not prevent atomized paint from attaching to a workpiece, and high-quality painting can be achieved by a coating gun  16  having a relatively low blowing pressure of shaping air. Further, since the conical ceiling wall  41  is provided on a surrounding area of the air blow-out unit  46  in the upper part of the inside of the painting booth  10 V, air flows down smoothly on the side-part surrounding wall  40  while being guided by the conical ceiling wall  41 , so that the air flow can prevent paint from attaching to the side-part surrounding wall  40  and a coating robot (not shown) adjacent to the inner side of the side-part surrounding wall  40 . 
     Other Embodiments 
     The present invention is not limited to the above embodiments, and, for example, embodiments described below are also included in the technical scope of the present invention. Further besides the embodiments below, the present invention can be variously modified and practiced without departing from the spirit of the invention. 
     (1) In the painting booth  10  of the first embodiment, a part of the air supply duct  32  corresponding to the “air supply unit” is arranged between the upper end parts of the inclined roofs  31  and  31 . However, as the painting booth  10 W shown in  FIG. 7 , an air supply duct  48  having a rectangular cross-section may be provided as the “air supply unit” above the inclined roofs  31  and  31 , and the entire part of the flat lower surface of the air supply duct  48  may be used as an aeration part  49  made up of a mesh and a filter mat. In addition, below the aeration part  49 , a plurality of air vent deflectors  47 Z extending in the longitudinal direction of the air supply duct  48  may be arranged in the width direction of the air supply duct  48 . Even with this configuration, if the inclination angles of the plurality of air vent deflectors  47 Z are made different such that the direction of wind is directed more sideward as being more distant sideward from the center of the air supply duct  48 , the same advantageous effects can be obtained as in the first embodiment. 
     (2) Further, in the painting booth  10 V of the second embodiment shown in  FIG. 6 , the lower part of the air supply duct  42  corresponding to the “air supply unit” is the hemispherical body  43 . However, without providing the hemispherical body  43 , the flat lower surface of the cylindrical body  44  may serve as an aeration part (not shown) made up of a mesh and a filter, and a plurality of annular air vent deflectors  47 A to  47 D shown in  FIG. 8  may be concentrically arranged below the aeration part. Even with this configuration, if the inclination angles of the plurality of air vent deflectors  47 A to  47 D are made different such that the direction of wind is directed more sideward as being more distant sideward from the center of the cylindrical body  44 , the same advantageous effects can be obtained as in the second embodiment. 
     (3) Inside the air supply duct  32  of the first embodiment, an air passing part may be provided in which a mesh is stretched to separate the semicircular arc part  33  from the rectangular part  34  and in which a filter mat is stacked on the mesh. With this configuration, in the entire inside of the semicircular arc part  33 , the internal pressure is more uniform, and the flow rate of the air blown out from the air blow-out unit  36  is stable. 
     (4) In the first and second embodiments, the side parts of the air supply ducts  32  and  42  in the upper part of the inside of the painting booths  10  and  10 V are inclined as the inclined roof  31  and the conical ceiling wall  41 . However, the side parts of the air supply ducts  32  and  42  in the upper part of the inside may be horizontal as the painting booth  10 X shown in  FIG. 9 . 
     (5) The air blow-out units  36  and  46  of the first and second embodiments are configured such that air passes through at any positions on the air blow-out units  36  and  46  at the same pressure loss. However, for example, the air blow-out units  36  and  46  may be configured such that the pressure loss is greater at the central part than at the side part, and air may be blown out at different flow rates depending on the position on the air blow-out units  36  and  46 . 
     (6) In each of the above embodiments, an air-permeable pressure reduction member according to the present invention is configured with a mesh and a filter mat. However, only a mesh or a filter mat can be used, and anything other than a mesh and a filter mat can also be used if air can pass therethrough while losing pressure. 
     DESCRIPTION OF THE REFERENCE NUMERAL 
     
         
         
           
               10 ,  10 V,  10 W,  10 X: Painting booth 
               30 A: First inner surface 
               31 : Inclined roof 
               31 A: First inclined ceiling surface 
               32 ,  42 ,  48 : Air supply duct (air supply unit) 
               33 : Semicircular arc part 
               36 ,  46 : Air blow-out unit 
               38 : Mesh (air-permeable pressure reduction member) 
               39 : Filter mat (air-permeable pressure reduction member) 
               40 : Side-part surrounding wall 
               41 : Conical ceiling wall 
               47 A to  47 D,  47 Z: Air vent deflector 
             H 1 : First horizontal direction 
             H 2 : Second horizontal direction 
             R 1 : Painting treatment area 
             W: Workpiece