The present invention relates to a painting device that applies paint to a workpiece by spraying the paint by jetting out shaping air.
When a workpiece such as a body of an automobile is painted, a painting device (a rotary atomization painting device) as disclosed in Japanese Patent No. 2600390, for example, is used. By rotating a bell-shaped cup to thereby discharge paint, and jetting shaping air toward the distal-end-side outer peripheral edge of the cup, this painting device atomizes the discharged paint and applies the paint to a workpiece. Moreover, the jet direction of the shaping air of the painting device is directed along a tangent to the outer peripheral edge of the cup when viewed in a front view (see FIG. 2 of Japanese Patent No. 2600390).
Incidentally, in this type of painting device, due to the spread of the jetted shaping air, the paint discharged from the cup is easily scattered in the radially outward direction of the painting device, and the application area of the paint on the workpiece tends to be large. As a result, for example, in the case of a workpiece with a narrow application range, the paint is not concentrated in an intended range, which undesirably reduces application efficiency and results in waste of paint.
The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a painting device that can improve the efficiency of application of paint to a workpiece by satisfactorily preventing the spread of the paint caused by shaping air with a simple configuration.
To attain the above-described object, the present invention is a painting device including: a bell-shaped cup configured to discharge paint; a housing configured to rotatably hold the cup; and a jetting port that is provided in the housing and located on a radially outward side and a proximal end side of a distal-end-side outer peripheral edge of the cup, the jetting port being configured to jet out shaping air in a distal-end direction to thereby spray the discharged paint toward a workpiece, wherein, if a circumscribed tangent which is tangent to the distal-end-side outer peripheral edge of the cup is drawn from the jetting port when viewed in a front view of the painting device, the shaping air is jetted out from the jetting port in a direction inclined radially inwardly of the cup with respect to the circumscribed tangent.
In accordance with the above, the painting device can satisfactorily prevent the paint from being spread by the shaping air with a simple configuration including the jetting port from which shaping air is jetted out in a direction inclined radially inwardly of the cup with respect to the circumscribed tangent. That is, by inclining the jet direction of the shaping air toward the inside with respect to the circumscribed tangent, the jetting port can cause the paint flying off by a centrifugal force associated with the rotation of the cup to be sprayed on a small area in the distal-end direction of the painting device, by the shaping air. As a result, the painting device achieves an improvement in the efficiency of application of the paint to a workpiece, and consequently applies the paint to, for example, a workpiece with a narrow application area in a concentrated manner. Therefore, it is possible to achieve a significant reduction in waste of paint.
In this case, when viewed in the front view, in the jetting port, the angle of inclination of the jet direction of the shaping air with respect to an intersection-point tangent that is tangent to the distal-end-side outer peripheral edge at an intersection point of the jet direction of the shaping air and the distal-end-side outer peripheral edge of the cup may be set so as to be smaller than or equal to 30°.
As described above, as a result of the angle of inclination of the jet direction of the shaping air being set so as to be smaller than or equal to 30°, the jetting port can satisfactorily narrow the range of the direction in which the paint actually flies.
Moreover, it is preferable that, within an area from the jetting port to the distal-end-side outer peripheral edge when viewed in a side view of the painting device, the jet direction of the shaping air in the jetting port is set so as to lie outside the distal-end-side outer peripheral edge when viewed in the front view.
As described above, by setting the jet direction of the shaping air so as to lie outside the distal-end-side outer peripheral edge in an area from the jetting port to the distal-end-side outer peripheral edge, the jetting port can make the shaping air sufficiently flow to a distal-end side beyond the distal-end-side outer peripheral edge of the cup. Therefore, the painting device can more satisfactorily narrow the range of the direction in which the paint flies.
Furthermore, it is preferable that the housing includes a regulating jetting port configured to jet out regulating air which regulates a spraying state of the paint, the regulating jetting port being disposed on a radially inward side and a proximal end side of the distal-end-side outer peripheral edge when viewed in the front view.
As described above, by producing a jet of regulating air from the regulating jetting port, the painting device can also spray the paint in such a way as to spread the paint radially outwardly of the cup, and thus it is possible to increase the flexibility of the application range of the paint.
According to the present invention, the painting device can satisfactorily prevent the paint from being spread by the shaping air with a simple configuration and improve the efficiency of application of the paint to a workpiece.
Hereinafter, a preferred embodiment of a painting device according to the present invention will be described in detail with reference to the attached drawings.
As depicted in
Specifically, the painting device 10 includes the above-described housing 14, an air motor 16 provided in the housing 14, a shaft 18 that is rotated by the air motor 16, the above-described cup 12 provided at a distal end of the shaft 18, and an air jetting unit 20 that jets shaping air.
The housing 14 forms a main exterior appearance of the painting device 10 and is formed so as to have a cylindrical shape as a whole. This housing 14 is formed so as to taper in a distal-end direction when viewed in a side sectional view, and an application unit that applies paint is provided on a distal-end side thereof. The application unit forms the air jetting unit 20 as a result of a plurality of structural members being assembled together, and further houses the air motor 16 and the shaft 18 therein.
The air motor 16 is provided so as to surround the radial outside of the shaft 18 and rotates the shaft 18, which is rotatably attached to the housing 14, at high speed by supply of compressed air from an unillustrated compressed air source. The shaft 18 is formed in the shape of a hollow cylinder and extends in the housing 14 in an axial direction, and an unillustrated high-voltage generating device is connected to a proximal end side thereof. A negative high voltage which is supplied from the high-voltage generating device is applied to the cup 12 on the distal-end side through the shaft 18 to thereby electrify the paint, whereby electrostatic painting is performed. In the shaft 18, a tube member 22 is provided.
The tube member 22 is a hollow tube extending in the central axis of the shaft 18 in the axial direction and has inside a paint supply channel 24 and a cleaning liquid supply channel 26. The paint supply channel 24 is connected, at a proximal end side thereof, to an unillustrated paint supply source, and allows the paint supplied from the paint supply source to flow therethrough in the distal-end direction. The cleaning liquid supply channel 26 is connected, at a proximal end side thereof, to an unillustrated cleaning liquid supply source, and allows a cleaning liquid supplied from the cleaning liquid supply source to flow therethrough in the distal-end direction. The paint supply channel 24 and the cleaning liquid supply channel 26 extend in parallel with each other to some midpoint of the tube member 22 in the distal-end direction, and then form a coaxial double-layer structure on the distal-end side of the tube member 22. On the distal-end side of the tube member 22, a paint supply nozzle 25 that discharges the paint is provided, and a cleaning liquid supply nozzle 27 that discharges the cleaning liquid is provided so as to surround the periphery of the paint supply nozzle 25.
The cup 12 that forms the application unit of the painting device 10 is fixed to the distal end of the shaft 18, and, when the shaft 18 is rotated by driving of the air motor 16, the cup 12 rotates integrally with the shaft 18. When viewed in a side sectional view, the cup 12 includes an inner member 28 that surrounds the perimeter of the paint supply nozzle 25 and the cleaning liquid supply nozzle 27 of the shaft 18, and an outer member 30 that houses the inner member 28 and is formed so as to widen (in the shape of a bell) in the distal-end direction.
The inner member 28 is formed into a substantially disc shape, and disposed closer to the proximal end side than a distal-end surface 46a of the housing 14 as viewed in a side sectional view. In the inner member 28, a reservoir portion 32 that temporarily stores the paint or the cleaning liquid which is supplied from the paint supply channel 24 or the cleaning liquid supply channel 26 is provided. The reservoir portion 32 is formed as a circular space when viewed in a front sectional view, and, in a wall portion of the inner member 28 forming the reservoir portion 32, a plurality of discharge holes 34 that discharge the paint are provided. These discharge holes 34 are formed in the front surface and the side circumferential surface of the inner member 28 so as to pass therethrough from the reservoir portion 32 and allow the paint supplied to the reservoir portion 32 to flow out.
The outer member 30 is formed so as to spread radially outwardly from the inner member 28 in the distal-end direction, and has inside a hollow portion 36 that allows the paint to flow therethrough. At the distal end of the outer member 30, an opening 36a that communicates with the hollow portion 36 and allows the paint to be discharged is formed. A distal-end-side outer peripheral edge 38 of the outer member 30 which surrounds the opening 36a is located closer to the distal-end side than the distal-end surface 46a of the housing 14.
The inner surface of the outer member 30 forming the hollow portion 36 is formed as a smooth surface that allows the paint to flow radially outwardly when viewed in a side sectional view. Moreover, part of the inner face near the opening 36a is a curved face that curves at a steep angle toward the outside of the outer member 30 in the radial direction thereof. As a result, the paint discharged from the discharge holes 34 of the inner member 28 flows on the inner surface by a centrifugal force generated by the rotation of the cup 12, and flies off from the opening 36a of the cup 12 in the direction of rotation of the cup 12 and in a radial outward flying-off direction (see
The air jetting unit 20 of the painting device 10 is provided in the housing 14 surrounding the cup 12. As depicted in
As depicted in
The first air chamber 48 is formed as a ring-shaped space provided in the circumferential direction on the proximal-end surface side of the end wall 46 of the housing 14. This first air chamber 48 temporarily stores air which is supplied from the first air supply channel 50, and makes the air flow into the plurality of first jet holes 42. The second air chamber 52 is formed as a ring-shaped space provided in the circumferential direction of the housing 14 on the proximal-end surface side of the end wall 46 of the housing 14 and inside the first air chamber 48. This second air chamber 52 temporarily stores air which is supplied from the second air supply channel 54, and makes the air flow into the plurality of second jet holes 44.
The first and second air supply channels 50, 54 are connected respectively to unillustrated air supply sources, and allow air, whose supply amount is controlled by each air supply source, to flow into the first and second air chambers 48 and 52, respectively. Here, the air jetting unit 20 has the function of spraying the paint toward the workpiece by the shaping air jetted from the first jet hole group 43 and regulating the application state of the paint by the shaping air jetted from the second jet hole group 45. Hereinafter, to make distinction between shaping airs, the shaping air from the second jet hole group 45 is referred to as regulating air.
That is, at the time of application of the paint, the air jetting unit 20 produces a high-speed jet of a large volume of shaping air ejected from the first distal-end openings 42a via the first air chamber 48 and the first jet holes 42 by supplying a large volume of air from the first air supply channel 50. On the other hand, the air jetting unit 20 produces a jet of a proper amount of regulating air from the second distal-end openings 44a via the second air chamber 52 and the second jet holes 44 by supplying, to the second air supply channel 54, the air whose supply amount is appropriately set in accordance with necessity such as the necessity to apply the paint while spreading the paint.
Moreover, the painting device 10 according to the present embodiment sets the jet direction of shaping air which is jetted out from the first distal-end openings 42a, by means of the first jet holes 42. That is, the first jet holes 42 extending through the end wall 46 are inclined from the radially outer side toward the radially inner side in the distal-end direction when viewed in the side sectional view shown in
Incidentally, in a manner opposite to the first jet holes 42, the second jet holes 44 are slightly inclined in the end wall 46 from the radially inner side toward the radially outer side in the distal-end direction. As a result, an extension line L2 (the jet direction of the shaping air) of the axis of each second jet hole 44 also passes through an area that is located slightly radially outwardly of the distal-end-side outer peripheral edge 38 of the cup 12.
Furthermore, the first jet holes 42 are diagonally inclined in the end wall 46 so that the first distal-end openings 42a and the first proximal-end openings 42b are out of phase with each other by a few degrees (do not overlap one another in the radial direction) in the circumferential direction when viewed in the front views shown in
As depicted in
Furthermore, when viewed in a side view shown in
The angle of inclination β of the jet direction with respect to the axial direction of the housing 14 is preferably set within a range of 30°≤α≤70°, for example. If the angle of inclination β is set in this way, even when shaping air is jetted out so as to be inclined toward the inside with respect to the circumscribed tangent T as viewed in a front view, the jet direction of the shaping air in the first jet hole 42 can be set so as to pass through an area that is located radially outwardly of the distal-end-side outer peripheral edge 38, at a position P at which the jet direction and the distal-end-side outer peripheral edge 38 of the cup 12 overlap each other as viewed in a side view. This makes it possible for the first jet hole 42 to produce a jet of shaping air in such a way that the shaping air enters the inside of the distal-end-side outer peripheral edge 38 of the cup 12 after passing a position near the distal-end-side outer peripheral edge 38 of the cup 12. Alternatively, the first distal-end opening 42a may produce a jet of shaping air in a jet direction such that the shaping air enters the inside of the distal-end-side outer peripheral edge 38 as viewed in a front view before passing the distal-end-side outer peripheral edge 38. In this case, although the force of flow of the shaping air on the distal-end side of the cup 12 is reduced, since part of the shaping air flows without interfering with the cup 12, it is possible to spray the paint on an inwardly-narrowed area in a manner similar to that described above.
The painting device 10 according to the present embodiment is basically configured as described above, and the operation and effect thereof will be described below.
When performing painting of a workpiece, the painting device 10 applies a high voltage to the shaft 18 and rotates the shaft 18 at high speed by supplying compressed air to the air motor 16, whereby the cup 12 is rotated in a counterclockwise direction as viewed in the front view shown in
After being discharged from the discharge holes 34, the paint flies in the distal-end direction by the negative pressure of the jet of shaping air therearound, and also flows on the inner surface of the outer member 30 toward the outside in the radial direction (the centrifugal direction). Then, as indicated by a vector shown by a dot and dash line of
On the one hand, the air jetting unit 20 of the painting device 10 supplies air from the air supply source and jets out shaping air from the first distal-end openings 42a of the first jet holes 42 via the first air supply channel 50 and the first air chamber 48. As described above, each first distal-end opening 42a jets shaping air toward the inside with respect to the circumscribed tangent T which extends from the first distal-end opening 42a so as to be tangent to the distal-end-side outer peripheral edge 38 of the cup 12 as viewed in a front view (see
On the other hand, a conventional painting device 100 has a configuration (the angle of inclination α=0°) in which the jet direction of shaping air coincides with a circumscribed tangent T which extends from a jetting port 102 so as to circumscribe (be tangent to) a distal-end-side outer peripheral edge 106 of a cup 104, as indicated by a vector shown by a tow-dot chain line depicted in
In contrast, by producing a jet of shaping air in the manner described above, the painting device 10 can cause the paint flying off from the distal-end-side outer peripheral edge 38 of the outer member 30 in the centrifugal direction to get closer to the inside. That is, as depicted in
Moreover, for coating a wider area with the paint, in the painting device 10, regulating air is jetted out from the second distal-end openings 44a of the second jet holes 44 in the distal-end direction and in the radially outward direction. As a result, a vector is added to the vector of the shaping air ejected from each of the first distal-end openings 42a so that the direction of the vector of the shaping air is shifted radially outwardly. Thus, it is possible to apply the paint to the workpiece while satisfactorily spreading the paint radially outwardly of the cup 12.
As described above, since the painting device 10 according to the present embodiment has the first distal-end openings 42a from which shaping air is jetted out in a direction inclined radially inwardly with respect to the circumscribed tangent T, it is possible to satisfactorily prevent the paint from being scattered by the shaping air. That is, with a simple configuration in which the jet direction of the shaping air is inclined toward the inside with respect to the circumscribed tangent T, a jet of shaping air which is jetted out from the first distal-end openings 42a can blow off the paint, which is discharged by the centrifugal force associated with the rotation of the cup 12, in the distal-end direction while preventing the paint from being spread over a wide area. As a result, the painting device 10 can achieve an improvement in the efficiency of application of the paint and apply the paint to, for example, a workpiece with a narrow application range in a concentrated manner.
In this case, as a result of the angle of inclination α of the jet direction of the shaping air being set so as to be smaller than or equal to 30°, the painting device 10 can further lessen the range of the direction in which the paint actually flies. Moreover, by setting the jet direction of the shaping air so as to lie outside the distal-end-side outer peripheral edge 38 within an area to the distal-end-side outer peripheral edge 38 when viewed in a side view, the first distal-end openings 42a can make the shaping air sufficiently flow to a distal-end side beyond the distal-end-side outer peripheral edge 38 of the cup 12. Therefore, the painting device 10 can lessen the range of the direction in which the paint flies more satisfactorily. Furthermore, by jetting out regulating air from the second distal-end openings 44a, the painting device 10 can also spray the paint in such a way as to spread the paint radially outwardly of the cup 12, and thus it is possible to increase the flexibility of the application range of the paint.
In the above description, the preferred embodiment of the present invention has been described, but it goes without saying that the present invention is not limited to the above-described embodiment and various changes and modifications are possible within the scope of the present invention. For example, the painting device 10 sets the jet direction of the shaping air based on the shape of the first jet hole 42, but the invention is not limited thereto; the jet direction of the shaping air from a jetting port may be set in various ways. Examples include a configuration in which a ring-shaped jetting port is formed in the circumferential direction of the housing 14 and the shaping air is made to flow in a spiral fashion in the housing 14, whereby the flow of the shaping air regulated so as to be inclined in the distal-end direction and in the radially inward direction of the cup 12 is jetted out from the jetting port.
Number | Date | Country | Kind |
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2015-112988 | Jun 2015 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2016/066494 | 6/2/2016 | WO | 00 |