WO2008093866A1

WO2008093866A1 - Rotary spray coating apparatus and method

Info

Publication number: WO2008093866A1
Application number: PCT/JP2008/051718
Authority: WO
Inventors: Kenyu Hoshino; Yoshiharu Komatsu; Yukihiko Shinbo; Takayuki Tahara
Original assignee: Honda Motor Co., Ltd.
Priority date: 2007-02-01
Filing date: 2008-01-29
Publication date: 2008-08-07
Also published as: JP2008188505A

Abstract

A rotary spray coating apparatus having an atomizer head (25) for discharging particulate paint and adapted to adjust the coating shape of the paint is disclosed. A first shaping air outlet (35) in the form of a ring is disposed on an external periphery of the atomizer head. At least one pair of second shaping air outlets (39) is provided in opposed relation to and near the first shaping air outlet. The shaping air discharged from the second shaping air outlets modifies the ring-shaped shaping air discharged from the first shaping air outlet into an elliptical shape.

Description

DESCRIPTION

ROTARY SPRAY COATING APPARATUS AND METHOD

Technical Field

The present invention relates to an improvement in a rotary spray coating apparatus wherein particulate paint is discharged from an atomizer head and the coating shape of the particulate paint is adjusted by using shaping air. The invention also relates to a rotary spray coating method using the apparatus.

Background Art

Rotary spray coating apparatuses that use shaping air to adjust the coating shape of atomized paint are often used for applying auto body paint. Minor adjustments to the coating shape can be made using this rotary spray coating apparatus, but major shape changes are difficult. In view of this situation, a rotary spray coating method that allows major shape changes to be made is disclosed in Japanese Patent No. 3254828 (JP 3254828 B).

The rotary spray coating apparatus of JP 3254828 B will be described below with reference to FIGS. 6A to 6C hereof. The rotary spray coating apparatus 100 shown in FIG. 6A is composed of an air motor 102 that is accommodated in a plastic housing 101, a cup-shaped atomizer head 104 that is mounted at the distal end of a rotating shaft 103 of the air motor 102, a shaping air nozzle 105 that is mounted at the end of the plastic housing 101 so as to surround the outer periphery of the atomizer head 104, a plurality of first air outlets 107 formed on the shaping air nozzle 105 so as to be connected to a first air channel 106 formed in the peripheral direction of the shaping air nozzle 105, and a plurality of second air outlets 109 formed on the shaping air nozzle 105 so as to be connected to a second air channel 108 that is disposed further on the external periphery away from the first air outlets 107 and is provided in the peripheral direction of the shaping air nozzle 105.

Shaping air 112 is emitted only from the first air outlets 107 when the coating object 111 is wide, as shown in FIG. 6B. Since the shaping air 112 is set in the torsional direction with respect to the axial center 113 of the rotating shaft 103, the diameter of the annular pattern of the shaping air 112 increases in relation to the distance from the first air outlets 107. As a result, a large-diameter coating shape 114 that matches the width of the coating object 111 can be obtained. Shaping air 116 is discharged from the second air outlets 109 in addition to the discharge of the shaping air 112 when the coating object 115 is narrow, as shown in FIG. 6C. Since the shaping air 116 is set to be parallel or cross- directional to the axial center 113 of the rotating shaft 103, the torsional direction of shaping air 112 is changed when the shaping air 116 collides with shaping air 112. Therefore, a small- diameter coating shape 117 that matches the width of the coating object 115 can be obtained because the diameter of the annular pattern of the shaping air 112 can be varied.

When a narrow coating object 115 such as that shown in FIG. 6C is coated with a large-diameter coating shape 114 shown in FIG. 6B, a large amount of paint is wasted and the coating efficiency is reduced. When the narrow coating object 115 is coated with a small-diameter coating shape 117 such as that shown in FIG. 6C, there is no loss of paint and coating efficiency is increased. However, time that is commensurate with the small diameter is required for the coating work when a coating is applied as the small- diameter coating shape 117 is moved from the top of the drawing to the bottom on the narrow coating object 115, and work efficiency is therefore reduced.

The development of a rotary spray coating method capable of efficiently forming a coating on a long, narrow coating object is needed because of the above-stated problems.

Disclosure of the Invention

According to a first aspect of the present invention, there is provided a rotary spray coating apparatus having an atomizer head for discharging particulate paint and adapted to adjust the coating shape of the particulate paint with shaping air, the apparatus comprising: first shaping air outlet means in the form of a ring disposed on an external periphery of the atomizer head; and second shaping air outlet means positioned rearwardly of the first shaping air outlet means and formed at a predetermined angle, wherein at least a pair of the second shaping air outlet means is disposed in opposed relation to and in a vicinity of the first shaping air outlet means.

In this arrangement, at least a pair of the outlets acting as the second shaping air outlet means is disposed in opposed relation to the outlets of the first shaping air outlet means in the vicinity thereof. Thus, the ring-shaped shaping air discharged from the first shaping air outlets can be sandwiched by the pair of shaping airs discharged from the second shaping air outlets. For this reason, the coating shape of the particulate paint can be modified from a circle to an oval or another shape. In other words, the length of the coating can be increased. It is consequently possible to obtain a rotary spray coating apparatus capable of efficiently forming a coating on long thin coating objects.

Preferably, each of the second shaping air outlet means comprises an air outlet section having a plurality of holes disposed in a row. In this arrangement, the flow of air is less likely to concentrate in specific locations because shaping air is discharged from a plurality of holes. For this reason, a contribution is made to the stability of the coating shape because the shaping air is dispersed and discharged as ring-shaped shaping air.

Desirably, the second shaping air outlet means comprises a plurality of pairs of air outlet sections, each being independent. With this arrangement, the coating shape of the particulate paint can be varied in a simple manner in accordance with the shape to be applied to the coating object, even when the shape to be applied to the coating the object changes. A rotary spray coating apparatus having improved work efficiency can therefore be obtained.

According to a second aspect of the present invention, there is provided a coating method by using a rotary spray coating apparatus having an atomizer head for discharging particulate paint and adapted to adjust the coating shape of the particulate paint with shaping air, which method comprising the steps of- causing ring-shaped first shaping air outlet means, disposed on an external periphery of the atomizer head, and at least a pair of second shaping air outlet means, disposed in a vicinity of the first shaping air outlet means, to discharge shaping air in accordance with a shape to be coated on a coating object, varying the coating shape of the particulate paint in accordance with the shape to be coated on the coating object. In this arrangement, shaping air is discharged from an air outlet, which is ring-shaped first shaping air outlet means, and is also discharged from an air outlet, which is second shaping air outlet means, in accordance with a shape to be coated on a coating object when a coating object is coated by a rotary spray coating apparatus; and the coating shape of the particulate paint is varied in accordance with the shape to be coated on the coating object. A rotary spray coating method that can coat long, thin coating objects with good efficiency can therefore be obtained.

In a preferred form, the second shaping air outlet means comprises a plurality of opposed pairs of air outlet sections each having a plurality of holes disposed in a row, each unit being independent, and the method comprises the step of causing the shaping air to be discharged from one unit of one of the opposed pairs of air outlet sections having plural holes. Thus, the rotary spray coating apparatus is not required to be rotated even when the shape to be applied to a coating object is horizontally long, vertically long, or another shape. A rotary spray coating method that further improves work efficiency can therefore be obtained.

For coating a narrow section of the coating object, the method preferably comprises the step of adjusting the coating shape of the particulate paint to an elliptical shape or a rectangular shape along a length of the narrow section. With this arrangement, the coating shape of the particulate paint can be easily made to match the shape to be coated on a coating object. As a result, a rotary spray coating method that improves work efficiency is provided.

Brief Description of the Drawings FIG. 1 is a cross-sectional view illustrating a rotary spray coating apparatus according to a first embodiment of the present invention; FIG. 2 is a view as seen in the direction of arrow 2 of FIG. Il FIGS. 3A to 3C are schematic views illustrating an operation of the rotary coating spray apparatus as a narrow section of a coating object is long and narrow in a horizontal direction, FIG. 3C being a cross-sectional view taken along line 3O3C of FIG. 3B;

FIGS. 4A to 4C are schematic views illustrating an operation of the rotary coating spray apparatus as the narrow section of the coating object is long and narrow in a vertical direction, FIG. 4C being a cross-sectional view taken along line 4C-4C of FIG. 4B;

FIG. 5 is a schematic view illustrating a rotary spray coating apparatus according to a second embodiment of the present invention; and

FIGS. 6A to 6C are schematic views illustrating a conventional rotary spray coating apparatus. Best Mode for Carrying out the Invention

The rotary spray coating apparatus 10 of the first embodiment shown in FIG. 1 is composed of a casing 13 having a cone section 11 formed at the distal end, and a cylinder 12 integrally formed with the cone section 11," a column- shaped housing block 16 provided with a male screw 15 that can be threaded into a female screw 14 formed on the inner periphery of the posterior end of the casing 13, and accommodated in the case 13 (described in detail below); a power air chamber block 18 fitted into a fitting hole 17 that is provided to the housing block 16; a slide bearing 21 that is fitted into the fitted hole 17 so as to be adjacent to the power air chamber block 18 and fixed to the housing block 16 using a plurality of hexagon socket-head bolts 19; a hollow rotary shaft 23 which is inserted into the slide bearing 21 and in which a vane 22 is formed at the posterior end; an atomizer head 25 mounted using a plurality of hexagon socket-head bolts 24 at the distal end of the rotary shaft 23; a sleeve 29 having a flange 28 at the posterior end for accommodating and mounting the atomizer head 25 to the distal end surface 26 of the slide bearing 21 using a plurality of cross-recessed flathead machine screws 27; a cover 34 having a cone section 33 at the distal end and a male screw 32 at the posterior end that can be threaded into a female screw 31 formed in the internal peripheral surface of the distal end of the cone section 11 in order to cover the sleeve 29; a toroidal first shaping air outlet 35 formed between the distal end of the cover 34 and the distal end of the sleeve 29; a toroidal manifold 36 mounted on the external peripheral surface of the casing 13 (described in detail below); a second shaping air feed port 38 formed by mounting a second shaping air pipe 37 to the rear of the manifold 36; and a second shaping air outlet 39 (described in detail below) that is composed of four air outlet sections (described in detail below) and that is formed at an angle θ of 20° from the manifold 36 to the forward horizontal line in a case in which the distance from the coating surface of a coating object is, for example, 200 mm. The mounting angle of the second shaping air outlet 39 was described as being 20°, but the mounting angle may be modified in accordance with the distance from the coating surface of a coating object.

In the description below, shaping air discharged from the toroidal first shaping air outlet 35 is first shaping air, and shaping air discharged from the second shaping air outlet 39 is second shaping air.

The internal block 16 has a first shaping air supply opening 41 formed in the axial direction; a power air feed pipe 42 mounted parallel to the first shaping air supply opening 41; a housing tube 44 mounted parallel to the power air feed pipe 42 via a support tube 43; a valve rod 45 housed parallel to the housing tube 44; a piston stop 48 and cylinder 47 that houses a piston 46 provided to the posterior end of the valve rod 45; a paint introduction section 49 formed on the front side of the piston stop 48; and a depression 52 that accommodates a high -voltage generator 51 on the lower side of the paint introduction section 49 in the drawing.

A first shaping air passage 53 is formed between the internal surface of the case 13 and cover 34, and the external surface of the housing block 16, slide bearing 21, and sleeve 29 so as to continue from the first shaping air feed outlet 41; and the first shaping air outlet 35 is provided to the front of the first shaping air passage 53.

A power air chamber 55 is formed between the vane 22 of the rotary shaft 23 and the power air chamber block 18 so as to be in communication with a power air supply opening 54. The power air supply opening 54 is formed in the power air chamber block 18 so as to be in communication with the power air feed pipe 42.

A paint channel 56 is formed between the housing tube 44 and the valve rod 45. The paint channel 56 is in communication with the paint feed section 49, and the paint feed section 49 is in communication with a paint supply channel 57 that is formed at the posterior end of the housing block 16.

A piston actuator air supply channel 58 is formed in the internal block 16 so as to be in communication with the interior of the cylinder 47.

The piston 46 is pneumatic, but a hydraulic [piston] may be used or changed to another actuating type. In the diagram, 59 is a U-bolt, 61 is a nut, 62 is a piping support, 63 is an O-ring, 64 is an O-ring groove, 65 is a pin, 66 is a compression coil spring, and 67 is a pipe joint.

The rotary shaft 23 is rotatably supported by the slide bearing 21, and is therefore rotated together with the atomizer head 25 by spraying power air on the vane 22. At this point, the housing tube 44 does not rotate because a gap 68 is provided between the rotary shaft 23 and the housing tube 44.

The second shaping air outlet 39 is composed of two pairs of air outlet sections, and the air outlet sections are independent from each other, as shown in FIG. 2. One pair of the air outlet sections of the second shaping air outlet 39 is composed of a first air outlet section 69 mounted on the upper part of the manifold 36, and a second air outlet section 71 disposed parallel to the first air outlet section 69 and mounted on the lower part of the manifold 36. The other pair of air outlet sections is disposed so as to be orthogonal to the second air outlet section 71, and is composed of a third air outlet section 72 mounted on the left side of the manifold 36 in the diagram, and a fourth air outlet section 73 mounted parallel to the third air outlet section 72 and mounted on the right side of the manifold 36 in the diagram. The first air outlet section 69, second air outlet section 71, third air outlet section 72, and fourth air outlet section 73 are set at 0°, 90°, 180°, and 270°, respectively, with respect to the toroidal manifold 36, case 13, and cover 34. However, the mounting angle of the air outlet sections is arbitrary because the mounting angle can be changed to, e.g., 45°, 135°, 225°, and 315° while keeping the angle between the assembles at 90°.

Six second shaping air outlet holes 74 are disposed in a row in the first air outlet section 69, second air outlet section 71, third air outlet section 72, and fourth air outlet section 73, respectively; and six second shaping air junction ports 75 are opened so as to be connected to the second shaping air outlet holes 74. The second shaping air outlet holes 74 and the interior of the manifold 36 are connected by these six second shaping air junction ports 75.

In this example, the six second shaping air outlet holes 74 and six second shaping air junction ports 75 are provided to the first air outlet section 69, second air outlet section 71, third air outlet section 72, and fourth air outlet section 73. However, the number of holes can be varied because the number can be increased or reduced in accordance with the dimensions of the rotary spray coating apparatus.

The second shaping air outlet 39 is composed of a first air outlet section 69 and second air outlet section 71 as a pair, or a third air outlet section 72 and a fourth air outlet section 73 as a pair, in which six second shaping air outlet holes 74 are disposed in a row. The flow of air is less likely to come together in a specific area because shaping air is discharged from the shaping air outlet holes 74. It is therefore possible to discharge and disperse the above shaping air as toroidal shaping air, thereby making a contribution to the stability of the coating shape.

Returning to FIG. 1, a strike plate 77, with which a valve plug 76 makes contact so as to block six second shaping air junction ports 75 provided in the front/back direction of the diagram, and which seats the valve plug 76, is provided to the internal wall of the toroidal manifold 36. The valve plug 76 is disposed at the distal end of a cylinder rod 78, and an air cylinder 79 is provided for moving the valve plug in the vertical direction in the diagram. The first air outlet section 69, second air outlet section 71, third air outlet section 72 (FIG. 2), and fourth air outlet section 73 (FIG. 2) are each provided with a valve plug 76, a strike plate 77, and an air cylinder 79 for a total of four sets.

Also, in FIG. 2, four air pipes 91 are connected to the four air cylinders 79. A first solenoid valve 92, a second solenoid valve 93, a third solenoid valve 94, and a fourth solenoid valve 95 are connected to the upstream side of the air pipes 91. A compressor 96 is connected to the upstream side of the first solenoid valve 92, second solenoid valve 93, third solenoid valve 94, and fourth solenoid valve 95 via the four air pipes 91

The operation of the first solenoid valve 92, second solenoid valve 93, third solenoid valve 94, and fourth solenoid valve 95 is performed by sending signals from the controller 97 to each of the solenoid valves in the manner indicated by the dashed lines.

First, the second shaping air is made to pass from the second shaping air pipe 37 (FIG. l), through the second shaping air feed port 38 (FIG. l), and into the toroidal manifold 36 in order to be discharged from the second shaping air outlet holes 74.

Next, the first solenoid valve 92 and the second solenoid valve 93, for example, are operated using the controller 97, and cylinder actuating air is fed to the two air cylinders 79, whereby the two valve plugs 76 (FIG. l) move so as to open the second shaping air junction ports 75. The inside of the manifold 36 is thereby connected to the second shaping air outlet holes 74 of the first air outlet section 69 and the second air outlet section 71.

In the description above, the number of solenoid valves that are operated at one time by the controller 97 is two, but since it is possible to operate one, three, or four [solenoid valves], the number of solenoid valves that can be operated at one time may be arbitrarily selected.

The controller 97 can arbitrarily select and operate the air cylinders 79, and can therefore arbitrarily select or combine air outlet sections from among the first air outlet section 69, second air outlet section 71, third air outlet section 72, and fourth air outlet section 73 as the air outlet sections from which the discharge of second shaping air is desired.

A circular coating shape can be modified by discharging second shaping air from the second shaping air outlet holes 74 of the first air outlet section 69 and second air outlet section 71 toward the particulate paint discharged from the twelve holes 81 of the rotating atomizer head 25 and the toroidal first shaping air discharged from the first shaping air outlet 35 toward the particulate paint, in a state in which the manifold 36 described above is connected to the second shaping air outlet holes of the first air outlet section 69 and the second air outlet section 71.

The operation of the rotary spray coating apparatus 10 constituted in the manner described above will be described next.

FIGS. 3A to 3C show the operation of a rotary spray coating device when a narrow section of a coating object is horizontally long and slender. In FIG. 3A, second shaping air 82 is discharged from the second shaping air outlet holes 74 of the first air outlet section 69 and the second air outlet section 71. At this point, the second shaping air outlet holes 74 of the third air outlet section 72 and the fourth air outlet section 73 are configured so that the second shaping air is not discharged from the second shaping air outlet holes 74 of the third air outlet section 72 and the fourth air outlet section 73 because the second shaping air junction ports 75 (FIG. 2) are closed by the valve plug 76 (FIG. 1).

In FIG. 3B, the toroidal first shaping air that contains particulate paint is modified by the second shaping air 82 shown in FIG. 3A to a horizontally long and narrow shape, and the particulate paint 83 is discharged toward a horizontally long narrow section 84 of the coating object 83.

As shown in FIG. 30, a horizontally long elliptical coating shape 85 can be obtained in accordance with the shape to be applied to the horizontally long narrow section 84 of the coating object. The horizontally elliptical coating shape 85 may also be a horizontally long rectangular shape along the lengthwise direction of the horizontally long narrow section 84 of the coating object.

FIGS. 4A to 4C show the operation of the rotary spray coating apparatus when the narrow section of the coating object is vertically long and slender.

In FIG. 4A, second shaping air 86 is discharged from the second shaping air outlet holes 74 of the third air outlet section 72 and the fourth air outlet section 73. At this point, the second shaping air outlet holes 74 of the first air outlet section 69 and the second air outlet section 71 is configured so that the second shaping air is not discharged from the second shaping air outlet holes 74 of the first air outlet section 69 and the second air outlet section 71 because the second shaping air junction ports 75 (FIG. 2) are closed by the valve plug 76 (FIG. 1).

In FIG. 4B, the toroidal first shaping air that contains particulate paint is modified by the second shaping air 86 shown in FIG. 4A to a vertically long and narrow shape, and the particulate paint 87 is discharged toward a vertically long narrow section 88 of the coating object.

As shown in FIG. 4C, a vertically long elliptical coating shape 89 can be obtained in accordance with the shape to be applied to the vertically long narrow section 88 of the coating object.

The vertically elliptical coating shape 89 may also be a vertically long rectangular shape along the lengthwise direction of the vertically long narrow section 88 of the coating object.

When a horizontally long narrow section 84 of a coating object or a vertically long narrow section 88 of a coating object is coated using the rotary spray coating apparatus 10, the coating shape of particulate paint can be made to match the shape to be applied to a coating object because the coating shape of particulate paint is set to an elliptical or rectangular shape along the lengthwise direction of the narrow section. Work efficiency can therefore be improved.

When paint is applied to a coating object by the rotary spray coating apparatus 10, shaping air is discharged from the toroidal first shaping air outlet 35 and the second shaping air outlets 39 in accordance with the shape to be applied to a coating object, and the coating shape of particulate paint can be varied so as to match the shape to be applied to a coating object. Paint can therefore be applied with good efficiency to a long slender coating object.

The rotary spray coating apparatus is not required to be rotated when the shape to be applied to a coating object is horizontally long, vertically long, or another shape because, when the rotary spray coating apparatus 10 is used, shaping air is discharged from one of two pairs of opposed air outlet sections, i.e., the first air outlet section 69 and the second air outlet section 71, or the third air outlet section 72 and the fourth air outlet section 73. It is therefore possible to further enhance work efficiency. Further, the second shaping air outlets 39 are comprised of two pairs of air outlet sections, each being independent. Specifically, the second shaping air outlets 39 are composed of a pair of air outlet sections, i.e., the first air outlet section 69 and the second air outlet section 71, and is composed of another pair of air outlet sections, i.e., the third air outlet section 72 and the fourth air outlet section 73. Thus, the coating shape of the particulate paint can be readily modified to match the shape to be applied to a coating object, even if the shape to be applied to a coating object is varied. It is therefore possible to provide a rotary spray coating apparatus in which work efficiency is improved.

The rotary spray coating apparatus 10 described to this point is provided with four air outlet sections, but there are cases in which at least one pair of air outlet sections, i.e., two air outlet sections are sufficient depending on the application. Also, fewer air outlet sections are more desirable from considerations related, to cost.

A second embodiment in which at least one pair of second shaping air outlets is disposed near the first shaping air outlet will be described next with reference to FIG. 5, whereupon the same reference numerals will be used to describe the structures that are the same as those in the second embodiment of FIG. 2.

Second shaping air outlets 39B are composed of a first air outlet section 69B and a second air outlet section 7 IB in a rotary spray coating apparatus 1OB. The first air outlet section 69B and the second air outlet section 71B are disposed as at least a pair at the top and bottom of the diagram, which is in the vicinity of the first shaping air outlets 35.

For this reason, the toroidal shaping air discharged from the first shaping air outlets 35 in the rotary spray coating apparatus 1OB can be placed between the pair of shaping air streams discharged from the second shaping air outlets 39. The coating shape of the particulate paint can thereby be modified from a circle to an oval or another shape. In other words, paint can be applied with good efficiency to a long slender coating object because the length of the coating can be increased.

The number of air outlet sections used in the embodiments in the present invention was described as four or two. However, eight air outlet sections can be provided by changing the angle between the air outlet sections to 45°, disposing the air outlet sections at, e.g., 0°, 45°, 90°, 135°, 180°, 225°, 270°, 315°, and 360°, and modifying the dimensions of the air outlet sections.

Industrial Applicability The rotary spray coating apparatus and rotary spray coating method of the present invention are suitable for applying paint to an auto body.

Claims

1. A rotary spray coating apparatus having an atomizer head for discharging particulate paint and adapted to adjust the coating shape of the particulate paint with shaping air, the apparatus comprising- first shaping air outlet means in the form of a ring disposed on an external periphery of the atomizer head; and second shaping air outlet means positioned rearwardly of the first shaping air outlet means and formed at a predetermined angle, wherein at least a pair of the second shaping air outlet means is disposed in opposed relation to and in a vicinity of the first shaping air outlet means.

2. The apparatus of claim 1, wherein each of the second shaping air outlet means comprises an air outlet section having a plurality of holes disposed in a row.

3. The apparatus of claim 2, wherein the second shaping air outlet means comprises a plurality of pairs of the air outlet sections each being independent.

4. A coating method by using a rotary spray coating apparatus having an atomizer head for discharging particulate paint and adapted to adjust the coating shape of the particulate paint with shaping air, the method comprising the steps of: causing ring-shaped first shaping air outlet means, disposed on an external periphery of the atomizer head, and at least a pair of second shaping air outlet means, disposed in a vicinity of the first shaping air outlet means, to discharge shaping air in accordance with a shape to be coated on a coating object, varying the coating shape of the particulate paint in accordance with the shape to be coated on the coating object.

5. The method of claim 4, wherein the second shaping air outlet means comprises a plurality of opposed pairs of air outlet sections each having a plurality of holes disposed in a row, each air outlet section being independent, and the method comprises the step of causing the shaping air to be discharged from one air outlet section of one of the opposed pairs of the air outlet sections.

6. The method of claim 5, further comprising the step of adjusting, for coating a narrow section of the coating object, the coating shape of the particulate paint to an elliptical shape or a rectangular shape along a length of the narrow section.