Painting System

Abstract

To provide a coating system capable of improving coating deposition efficiency and shortening a coating booth length in simultaneously coating and conveying a coating object material.SOLUTION: A coating system 10 for coating a body 100 while conveying the body 100 along a prescribed conveyance route includes: a gate mechanism 30 arranged over the conveyance route; a plurality of electrostatic atomization coating mechanisms 50 in which a plurality of electrostatic atomization nozzles 52 are arranged; and a plurality of shaft mechanisms 40 arranged in the gate mechanism 30 and individually supporting the electrostatic atomization coating mechanisms 50. Each of the shaft mechanisms 40 is constituted so as to adjust a distance of the electrostatic atomization coating mechanism 50 supported thereby from an outside plate coated surface of the body 100, and is constituted in a way that each of the electrostatic atomization coating mechanisms 50 can be arranged so that the whole or a part of the outside plate coated surface of the body 100 can be coated, when the gate mechanism 30 is viewed along the conveyance route.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a coating system that paints an exterior panel surface of an object to be coated while transporting the object along a predetermined transport path. [Background technology]

[0002] Conventionally, in a painting system for painting objects such as automobiles, railway cars, and aircraft, the object is transported along a predetermined transport path within a painting chamber, and the object is painted using spray mechanisms supported by multiple robot arms arranged along the transport path.

[0003] The robot arm may be an orthogonal two-axis type, an orthogonal three-axis type, or an articulated six-axis type (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2012-506305 Summary of the Invention [Problem to be solved by the invention]

[0005] However, such conventional painting systems required space to allow the spray mechanism supported by the robot arm to move freely along the outer panel surface of the object to be coated. Furthermore, conventional painting systems were configured to install multiple robot arms along the transport path, which tended to make the painting booth long.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a coating system that can improve coating efficiency and shorten the length of the coating booth when coating an object while transporting it. [Means for solving the problem]

[0007] The characteristic configuration of the coating system according to the present invention for achieving the above object is a coating system which paints an outer panel coating surface of an object to be coated while conveying the object along a predetermined conveying path, In the right position Placed The housing has a pair of pillars and a through portion provided across the pillars. a gate mechanism, a plurality of electrostatic atomization coating mechanisms each having a plurality of electrostatic atomization nozzles arranged in parallel; Pillar and crosspiece To In a row and a plurality of shaft mechanisms for individually supporting the electrostatic atomization coating mechanisms. The electrostatic atomization coating mechanism has a nozzle head made of a non-conductive material or a weakly conductive material, Each of the shaft mechanisms is configured to be capable of adjusting the coating distance of the electrostatic atomization coating mechanism supported by each of the shaft mechanisms from the exterior panel surface to be coated, and is configured to be capable of disposing each of the electrostatic atomization coating mechanisms so as to coat the entire or part of the exterior panel surface when the gate mechanism is viewed along the transport path. The row of shaft mechanisms in the column portion and the row of shaft mechanisms in the through portion are shifted forward and backward along the conveying path. The point is that...

[0008] The electrostatic atomization coating mechanism is configured to atomize the electrically charged paint discharged from the electrostatic atomization nozzle by the action of an electric field formed around the electrostatic atomization nozzle. The atomized electrically charged paint is electrostatically attracted to the object to be coated by the potential difference between the object to be coated and the electrostatic atomization coating mechanism, and flies and is applied to the exterior coating surface of the object to be coated.

[0009] In the electrostatic atomization coating mechanism, the paint flies along the electric field lines, but by providing needle electrodes around a group of electrostatic atomization nozzles and controlling the voltage applied by the needle electrodes, the spray pattern and coating area can be controlled, making it possible to adjust or avoid overlapping of coating areas of adjacent electrostatic atomization coating mechanisms.

[0010] The electrostatic atomizing nozzle of the electrostatic atomizing coating mechanism does not use compressed air to atomize the paint, so the paint is less likely to splash around because there is no air current generated by the electrostatic atomizing nozzle around the workpiece. Therefore, the coating efficiency is better than that of electrostatic atomizing nozzles such as rotary atomizing nozzles. However, the electrostatic atomizing nozzle has a limited application to painting small parts, etc., because the amount of paint discharged per given time is small.

[0011] When painting using such an electrostatic atomization coating mechanism supported by a robot arm, it is necessary to slow down the transport speed of the workpiece or to install multiple robot arms along the transport direction, which increases the time and transport distance required for painting.

[0012] The optimal painting distance for the electrostatic atomization coating mechanism is close to 50 to 120 mm from the exterior surface of the coating, and in order to achieve a uniform coating thickness, it is necessary to position the electrostatic atomization coating mechanism at an appropriate painting distance from the exterior surface of the coating. For example, if the exterior surface of the coating object has a complex shape, it is necessary to change the position of the electrostatic atomization coating mechanism according to the change in shape of the exterior surface passing through the gate mechanism.

[0013] According to the above-mentioned configuration, each electrostatic atomization coating mechanism can be positioned so that, when viewed from the gate mechanism along the transport path, it can paint the entire surface or part of the exterior panel to be coated, i.e., any desired location, from an appropriate coating distance that provides good coating efficiency. Therefore, the entire surface can be coated with high quality by simply passing the object through the gate mechanism once, thereby shortening the length of the coating booth.

[0014] According to the present invention, the length of the painting booth can be reduced to a maximum of 1 / 15 compared to a conventional painting system in which painting is performed using a rotary atomizing nozzle supported by a robot arm.

[0015] The electrostatic atomizing nozzle of the electrostatic atomizing coating mechanism has a coating efficiency of nearly 100%, and because the length of the coating booth can be shortened, the intake and exhaust volume required for coating can be reduced to a maximum of 1 / 150 of the intake and exhaust volume required for coating with a rotary atomizing nozzle attached to an articulated robot. Therefore, it is possible to simplify the large-scale intake and exhaust equipment required in conventional coating systems to exhaust the paint mist that has not been applied to the workpiece from the coating room, and the recovery equipment for recovering the exhausted paint mist.

[0016] When the transport direction of the workpiece is the X-direction, the more electrostatic atomization nozzles are arranged in the X-direction, the more difficult it is to maintain coating quality in terms of coating thickness and smoothness when the exterior panel surface has a curved surface, since the distance between each electrostatic atomization nozzle and the exterior panel surface becomes non-uniform. For this reason, the number of electrostatic atomization nozzles is determined based on the allowable range of coating thickness so as to ensure coating quality according to the shape of the exterior panel surface.

[0017] Each electrostatic atomization coating mechanism may have the same configuration or different configurations. For example, when each electrostatic atomization coating mechanism has a different configuration, it is possible to make the number of electrostatic atomization nozzles in each electrostatic atomization coating mechanism and the arrangement pattern different. The number of electrostatic atomization nozzles in the X direction and the number of electrostatic atomization coating mechanisms are designed based on the target coating thickness, the transport speed of the workpiece, and the coating capacity of the electrostatic atomization nozzles.

[0018] For example, if the object to be coated is the body of an automobile, it is conceivable that a large number of electrostatic atomization nozzles would be configured in an electrostatic atomization coating mechanism that corresponds to areas of the exterior panel surface with small curvature (e.g., the bonnet or roof), and a smaller number of electrostatic atomization nozzles would be configured in an electrostatic atomization coating mechanism that corresponds to areas with large curvature (e.g., fenders).

[0019] That is, when the surface of the exterior panel to be coated is curved, if there are too many electrostatic atomizing nozzles arranged, all of the electrostatic atomizing nozzles cannot simultaneously maintain the optimal coating distance from the surface of the exterior panel to be coated, so in such an electrostatic atomizing coating mechanism, the number of electrostatic atomizing nozzles arranged in the direction along the conveying direction is set to be small, and therefore, when the surface of the exterior panel to be coated is inclined, the actual coating area is large compared to the projected coating area, that is, the apparent coating capacity per unit time is relatively low, so in such an electrostatic atomizing spray mechanism, the number of electrostatic atomizing nozzles arranged in the direction along the conveying direction is set to be large, or multiple rows of electrostatic atomizing spray mechanisms are arranged along the conveying direction, and therefore, the coating quality can be ensured.

[0020] In the present invention, the gate mechanism comprises a pair of pillars arranged on either side of the conveying path and a through portion provided across the pair of pillars, and each of the shaft mechanisms is preferably arranged so as to form a single row at each of the pillars and the through portion when the gate mechanism is viewed along a direction perpendicular to the conveying path, or is preferably arranged in a plurality of rows in the front-to-rear direction of the conveying path, with the pitch of adjacent rows being the same or shifted.

[0021] For example, if the shaft mechanisms are arranged in a line, the dimensions of the gate mechanism in the transport direction of the workpiece can be made compact.

[0022] Furthermore, if the shaft mechanisms are arranged in multiple rows in the front-to-rear direction of the conveying path, the entire surface of the workpiece can be coated multiple times by simply passing the workpiece through the gate mechanism once.

[0023] Furthermore, if each shaft mechanism is arranged in multiple rows with the pitch shifted between adjacent rows, there is sufficient space between adjacent electrostatic atomization spray mechanisms, thereby avoiding the risk of the adjacent electrostatic atomization spray mechanisms coming into contact with each other.

[0024] In the present invention, it is preferable that each of the shaft mechanisms is arranged in multiple rows in the fore-and-aft direction of the transport path in each of the column portions and the through portions, with the pitch of adjacent rows being shifted by half a pitch, and that when the gate mechanism is viewed along the transport path, portions of the ends of the multiple electrostatic atomization nozzles possessed by each of adjacent electrostatic atomization painting mechanisms overlap.

[0025] Since each shaft mechanism is arranged in a plurality of rows, with the adjacent rows being shifted by half a pitch, there is a margin in the arrangement of adjacent electrostatic atomization coating mechanisms, and the risk of the adjacent electrostatic atomization coating mechanisms coming into contact with each other can be avoided. In this case, when the gate mechanism is viewed along the transport path, the ends of the electrostatic atomization nozzles of the adjacent electrostatic atomization coating mechanisms are arranged so as to overlap, so that there is no area between the adjacent electrostatic atomization coating mechanisms where painting cannot be performed. There is also no area between the electrostatic atomization coating mechanism located closest to the cross section in the column section and the electrostatic atomization coating mechanism located closest to the column section in the cross section where painting cannot be performed. It is preferable that the row in the column section and the row in the cross section are shifted from each other in the front-rear direction of the transport path.

[0026] In the present invention, it is preferable that the shaft mechanism supports the electrostatic atomization coating mechanism so as to be rotatable at least about an axis along the transport path, or about an axis perpendicular to the transport path.

[0027] In order to achieve a uniform coating thickness, the electrostatic atomization coating mechanism needs to be directly opposed to the surface of the exterior panel to be coated. For example, when the surface of the exterior panel to be coated has a complex shape, the position of the electrostatic atomization coating mechanism needs to be changed in accordance with the change in shape of the exterior panel surface passing through the gate mechanism. According to the above-mentioned configuration, in an electrostatic atomization coating mechanism that does not directly face the surface of the exterior panel to be coated, the shaft mechanism can ensure coating quality by rotating the electrostatic atomization coating mechanism about an axis that is aligned with the transport path or about an axis that is perpendicular to the transport path.

[0028] In the present invention, it is preferable that the gate mechanism is configured to be at least movable along the conveying direction, or to be capable of changing its position relative to the outer panel surface to be coated.

[0029] For example, when the object to be painted is the body of an automobile, and it is necessary to paint the front and rear of the automobile, the electrostatic atomization painting mechanism can be set to an appropriate painting distance and painting posture by changing the position of the gate mechanism relative to the transport path and the posture of the gate mechanism itself, without having to configure a large movable range for rotating the electrostatic atomization painting mechanism by the shaft mechanism.

[0030] In the present invention, a control mechanism is provided for controlling the painting system, and it is preferable that the control mechanism is configured to be able to individually control each shaft mechanism based on shape data of the exterior panel surface of the object to be coated at the time of design, shape data of the exterior panel surface of the object to be coated measured before the object to be coated is transported, or shape data of the exterior panel surface of the object to be coated measured immediately before painting while the object to be coated is being transported.

[0031] Since the optimal painting distance and painting posture for adjacent electrostatic atomization painting mechanisms differ depending on the shape of the exterior panel surface of the object to be coated, the control mechanism, as described above, can individually position each electrostatic atomization painting mechanism at the optimal painting distance from the exterior panel surface and place it in the optimal painting posture relative to the exterior panel surface, thereby maintaining painting quality.

[0032] The control of each shaft mechanism may be performed for each shaft mechanism, or for each group of a predetermined number of adjacent shaft mechanisms.

[0033] In the present invention, a control mechanism is provided for controlling the painting system, and it is preferable that the control mechanism is configured to be able to control the discharge of paint from each of the electrostatic atomization nozzles or each of the electrostatic atomization painting mechanisms based on shape data of the exterior panel surface of the object to be coated at the time of design, shape data of the exterior panel surface of the object to be coated measured before the object to be coated is transported, or shape data of the exterior panel surface of the object to be coated measured immediately before painting while the object to be coated is being transported.

[0034] Since the discharge of each electrostatic atomizing nozzle and each electrostatic atomizing coating mechanism can be controlled, it is possible to freely change the spray pattern and make the coating thickness uniform or non-uniform.

[0035] For example, when the electrostatic atomization coating mechanism is rotated when the shape of the surface to be coated of the exterior panel is not flat, the coating areas of adjacent electrostatic atomization coating mechanisms may overlap, and if paint is discharged from both of the adjacent electrostatic atomization coating mechanisms, the coating film will be thick in the overlapping areas. In both electrostatic atomization coating mechanisms with overlapping coating areas, the amount of paint discharged from the electrostatic atomization nozzle or electrostatic atomization coating mechanism that discharges paint to the overlapping areas, among the electrostatic atomization nozzles of at least one of the electrostatic atomization coating mechanisms, is reduced or stopped, or the coating area is controlled by controlling the voltage applied by the needle electrode, thereby making it possible to make the coating film thickness uniform even in the overlapping areas, and thus maintaining the coating quality.

[0036] In addition, if the amount of paint discharged from the electrostatic atomizing nozzle or electrostatic atomizing coating mechanism is constant, the coating thickness will be thin when the transport speed of the workpiece is fast, and the coating thickness will be thick when the transport speed of the workpiece is slow. The desired coating thickness can be obtained by controlling the amount of paint discharged from the electrostatic atomizing nozzle or electrostatic atomizing coating mechanism according to the transport speed of the workpiece. In order to obtain the required coating thickness, multiple rows of electrostatic atomizing nozzles may be arranged in the electrostatic atomizing coating mechanism, or multiple rows of electrostatic atomizing coating mechanisms may be provided in the coating area.

[0037] Furthermore, when the exterior panel surface to be painted is curved, the actual painting area is larger than the projected painting area, meaning that the apparent painting capacity per unit time is relatively low. Therefore, in such an electrostatic atomization painting mechanism, the painting quality can be ensured by increasing the amount of paint discharged from the electrostatic atomization nozzle or electrostatic atomization painting mechanism in the direction along the transport direction.

[0038] In some cases, there may be no outer panel surface to be painted by the electrostatic atomizing nozzle or electrostatic atomizing coating mechanism at the edge of the outer panel surface of the workpiece. In such cases, the electrostatic atomizing nozzle or electrostatic atomizing coating mechanism can be put into a non-discharge state to avoid unnecessary consumption of paint.

[0039] The discharge of paint from the electrostatic atomizing nozzles or electrostatic atomizing coating mechanisms may be controlled for each electrostatic atomizing nozzle or each electrostatic atomizing coating mechanism, or may be controlled for each group of a predetermined number of adjacent electrostatic atomizing nozzles or each group of a predetermined number of adjacent electrostatic atomizing coating mechanisms. Also, for example, when multiple rows of electrostatic atomizing nozzles are arranged in the electrostatic atomizing coating mechanism, the discharge of paint from the electrostatic atomizing nozzles or the electrostatic atomizing coating mechanism may be controlled for each row of the electrostatic atomizing nozzles, or when multiple rows of electrostatic atomizing coating mechanisms are arranged, the discharge of paint from the electrostatic atomizing coating mechanism may be controlled for each row of the electrostatic atomizing coating mechanisms.

[0040] In the present invention, a control mechanism is provided for controlling the painting system, and it is preferable that the control mechanism is configured to be able to identify the position and orientation of the workpiece on the transport path based on characteristic points of the outer panel coating surface of the workpiece and reference points defined on the transport path.

[0041] According to the above-mentioned configuration, the actual position and orientation of the workpiece on the transport path can be identified, so that the shaft mechanism can be controlled with high accuracy. [Brief description of the drawings]

[0042] [Figure 1] FIG. 1 is a front view of a painting system according to the present invention. [Diagram 2] FIG. 2 is a side view of the painting system shown in FIG. [Diagram 3] FIG. 2 is a plan view of the painting system shown in FIG. [Figure 4] An explanatory diagram of the front of the body and painting. [Diagram 5] 5 is an explanatory diagram of the extension and contraction of the shaft mechanism and the rotation of the electrostatic atomization coating mechanism. FIG. [Figure 6] 5 is an explanatory diagram of the extension and contraction of the shaft mechanism and the rotation of the electrostatic atomization coating mechanism. FIG. [Figure 7] FIG. 2 is an explanatory diagram of an electrostatic atomization coating mechanism. [Figure 8] FIG. 11 is an explanatory diagram of an electrostatic atomization coating mechanism according to another embodiment. [Figure 9] FIG. 11 is an explanatory diagram of a gate mechanism according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] An embodiment of the painting system according to the present invention will be described with reference to the drawings. Figures 1, 2, 3 and 4 show a painting system 10 for painting an automobile body 100 as an object to be painted. In Figures 1, 2, 3 and 4, the conveying direction of the body 100 is defined as the X direction, the direction perpendicular to the conveying direction of the body 100 in a horizontal plane is defined as the Y direction, and the direction perpendicular to the conveying direction of the body 100 in a vertical plane is defined as the Z direction.

[0044] The painting system 10 includes a conveyor mechanism 20 that transports a body 100 along a predetermined transport path inside the painting booth, a gate mechanism 30 that is arranged across the body 100 transported by the conveyor mechanism 20, a plurality of shaft mechanisms 40 that are arranged on the gate mechanism 30, a plurality of electrostatic atomization painting mechanisms 50 supported by each shaft mechanism 40, and a control mechanism that controls the painting system 10.

[0045] The gate mechanism 30 includes a pair of pillars 31 arranged at a position straddling the transport path of the conveyor mechanism 20, and a penetrating portion 32 provided across the pillars 31, and is movable along the transport path of the conveyor mechanism 20 by a moving mechanism (not shown). Note that the gate mechanism 30 may be configured to be rotatable around the lower ends of the pillars 31, or the penetrating portion 32 may be configured to be movable up and down along the pillars 31.

[0046] Each shaft mechanism 40 is configured to be able to adjust the painting distance of the electrostatic atomization painting mechanism 50 it supports relative to the exterior panel surface of the body 100, and is configured to be able to position each electrostatic atomization painting mechanism 50 so that it can paint the entire or part of the exterior panel surface when viewed from the gate mechanism 30 along the transport path of the conveyor mechanism 20.

[0047] In this embodiment, the shaft mechanisms 40 are arranged in two rows in the X direction along the Z direction in the pillar portion 31, and the shaft mechanisms 40 are arranged in two rows in the X direction along the Y direction in the penetrating portion 32. In this case, the shaft mechanisms 40 are arranged so as to be shifted by half a pitch between adjacent rows, and are arranged so that the ends of the electrostatic atomization nozzles 52 of adjacent electrostatic atomization coating mechanisms 50 overlap when the gate mechanism 30 is viewed along the X direction. In addition, the row of the shaft mechanisms 40 in the pillar portion 31 and the row of the shaft mechanisms 40 in the penetrating portion 32 are shifted forward and backward along the X direction.

[0048] The shaft mechanism 40 is composed of a double-acting actuator having a cylinder 41 and a rod 42 that is electromagnetically controlled to move forward and backward relative to the cylinder 41. However, the shaft mechanism 40 may be composed of a double-acting actuator having a cylinder 41 and a rod 42 that is hydraulically or pneumatically controlled to move forward and backward relative to the cylinder 41.

[0049] Each shaft mechanism 40 can move the electrostatic atomization coating mechanism 50 supported at the tip of the rod 42 closer to or farther away from the outer panel surface of the body 100 to be coated by moving the rod 42 forward and backward relative to the cylinder 41.

[0050] This allows each electrostatic atomization coating mechanism 50 to perform coating from an appropriate coating distance that provides good coating efficiency, for example, from a position of 50 to 120 mm from the exterior panel surface to be coated.

[0051] Furthermore, the shaft mechanism 40 is provided with a support mechanism 43 at the tip of the rod 42 , and the electrostatic atomization coating mechanism 50 is supported by the shaft mechanism 40 via the support mechanism 43 .

[0052] The support mechanism 43 has an electrically controlled servo motor or the like, and is configured to support the electrostatic atomization coating mechanism 50 so that it can rotate about an axis along the X direction (see FIG. 5) and about an axis along the Y direction or Z direction (see FIG. 6). The rotation angle is set to about ±20 degrees in the X direction and about ±90 degrees in the Y direction and Z direction, centered on the forward / backward direction of the support mechanism 43. However, the rotation angle is not limited to this.

[0053] As a result, the shaft mechanism 40 can place the electrostatic atomization coating mechanism 50 in an appropriate coating position relative to the exterior panel surface of the body 100. For example, when viewed from the X direction, the electrostatic atomization coating mechanism 50 does not face the exterior panel surface of the body 100, by rotating the electrostatic atomization coating mechanism 50, it can be made to face the exterior panel surface.

[0054] Furthermore, the shaft mechanism 40 rotates the electrostatic atomization painting mechanism 50 around an axis along the X direction, or supports and rotates the electrostatic atomization painting mechanism 50 around an axis along the Y direction or the Z direction, so that painting can be performed at the same location on the exterior panel surface of the body 100 being transported, and painting can be performed even if the shape of the exterior panel surface is not flat, thereby ensuring painting quality.

[0055] The electrostatic atomization coating mechanism 50 comprises a nozzle head 51, a plurality of electrostatic atomization nozzles 52 arranged in a line on the nozzle head 51, a paint supply mechanism which supplies paint to each electrostatic atomization nozzle 52, the voltage application mechanism which imparts a potential difference between each nozzle head 51 and the exterior panel surface to be coated, the switching mechanism which switches between a paint ejection state and a non-ejection state of a predetermined number of electrostatic atomization nozzles 52, and a needle electrode 53 provided on the nozzle head 51.

[0056] 7, the nozzle head 51 has 100 electrostatic atomization nozzles 52 arranged in a line with a pitch of 3 mm between adjacent nozzles along the Y direction in the electrostatic atomization coating mechanism 50 supported by the shaft mechanism 40 provided on the through section 32, and along the Z direction in the electrostatic atomization coating mechanism 50 supported by the shaft mechanism 40 provided on the pillar section 31. The amount of paint discharged from the electrostatic atomization coating mechanism 50 is set to 100 cc / min. Since the electrostatic atomization nozzle 52 does not use compressed air to atomize the paint, there is no air current generated by the electrostatic atomization nozzle 52 around the body 100, and as a result, the paint is less likely to scatter, resulting in good coating efficiency.

[0057] The arrangement of the electrostatic atomization nozzles 52 in the nozzle head 51 is not limited to the above-mentioned configuration. The electrostatic atomization nozzles 52 may be arranged in two rows of a dot matrix as shown in Fig. 8. As long as a uniform coating distribution is obtained, this can be changed as appropriate depending on the shape of the exterior coating surface of the body 100, the coating specifications, etc.

[0058] Furthermore, the nozzle head 51 is formed from a non-conductive material or a weakly conductive material, so that even if the nozzle head 51 to which a high voltage is applied by the voltage application mechanism unexpectedly comes close to another object, discharge between the nozzle head 51 and the other object is prevented.

[0059] The paint supply mechanism includes a storage tank for storing paint, a supply pump for supplying paint from the storage tank, and a supply hose for supplying paint from the storage tank to electrostatic atomization nozzle 52. The supply pump supplies paint from the storage tank through the supply hose to electrostatic atomization nozzle 52. The supply pump is configured to be able to adjust the amount of paint supplied.

[0060] The voltage application mechanism applies a potential difference between the nozzle head 51 and the surface of the outer panel to be coated. The paint used has an electrical resistance of about 1 to 20 MΩcm.

[0061] An electric field is formed around each electrostatic atomizing nozzle 52 by applying a high voltage (a positive or negative voltage of 5 to 60 kV) by the voltage application mechanism, and the charged paint ejected from each electrostatic atomizing nozzle 52 is atomized by the action of the electric field formed around each electrostatic atomizing nozzle 52, in what is known as electrostatic spray. The atomized charged paint is electrostatically attracted to the exterior panel surface due to the potential difference between the nozzle head 51 and the exterior panel surface, and flies and is applied to the exterior panel surface.

[0062] In electrostatic atomization coating mechanism 50, paint ejected from electrostatic atomization nozzle 52 flies along electric field lines. By controlling the voltage applied by needle electrode 53, the spray pattern can be controlled, and the coating area can be controlled.

[0063] Since the 100 electrostatic atomization nozzles 52 are arranged in the nozzle head 51 at a pitch of 3 mm, even if mutual electric field interference occurs between adjacent electrostatic atomization nozzles 52 around the electrostatic atomization nozzles 52, the electric field is formed uniformly without bias. As a result, the atomization of the charged paint sprayed from the electrostatic atomization nozzles 52 is uniform, improving the coating quality of the object to be coated.

[0064] In addition, it is also possible to effectively prevent a situation in which insufficiently atomized paint adheres to the nozzle head 51 due to insufficient atomization of the charged paint sprayed from some of the electrostatic atomization nozzles 52 caused by an imbalance in the electric field, thereby reducing the burden of cleaning and maintaining the nozzle head 51.

[0065] The switching mechanism is composed of an opening / closing valve that switches each group of a predetermined number of electrostatic atomizing nozzles 52 between a paint discharging state and a paint non-discharging state.

[0066] The control mechanism is composed of a control panel, etc., and is configured to control the transportation and transport speed of the body 100 by the conveyor mechanism 20, control the movement of the gate mechanism 30, control the advance and retreat of the rod 42 of the shaft mechanism 40, control the rotation of the support mechanism 43, and control the paint supply mechanism, the voltage application mechanism, the switching mechanism and the needle electrode 53 of the electrostatic atomization painting mechanism 50, based on shape data of the outer panel coating surface of the body 100 measured by so-called three-dimensional measurement before the body 100 is transported.

[0067] In the three-dimensional measurement, characteristic points of the coated exterior surface of the body 100 and reference points defined on the transport path can be measured, and the control mechanism is configured to be able to identify the position and orientation of the body 100 on the transport path based on the characteristic points and the reference points. This makes it possible to identify the actual position and orientation of the body 100 on the transport path, and therefore allows for accurate control of the shaft mechanism 40. However, the shape data of the coated exterior surface of the body 100 may be measured by other measurement methods instead of the above measurement methods.

[0068] For example, when the electrostatic atomization coating mechanisms 50 are rotated when the shape of the exterior panel surface to be coated is not flat, the coating areas of adjacent electrostatic atomization coating mechanisms 50 may overlap, and if paint is discharged from both of the adjacent electrostatic atomization coating mechanisms 50, the coating film will be thick in the overlapping areas. In both electrostatic atomization coating mechanisms 50 with overlapping coating areas, the amount of paint discharged from the electrostatic atomization nozzles 52 or electrostatic atomization coating mechanisms 50 that discharge paint to the overlapping areas among the electrostatic atomization nozzles 52 possessed by at least one of the electrostatic atomization coating mechanisms 50 can be reduced or stopped, or the coating area can be controlled by controlling the voltage applied by the needle electrodes 53, thereby making it possible to maintain the coating quality even in the overlapping areas.

[0069] Also, at the end of the outer panel surface to be coated of the body 100, there may be no outer panel surface to be coated by the electrostatic atomization nozzle 52 of the electrostatic atomization coating mechanism 50. In such a case, the electrostatic atomization nozzle 52 is put into a non-discharge state to avoid unnecessary consumption of paint.

[0070] Furthermore, when the exterior panel surface to be painted is curved as viewed from the transport direction of the body 100, the actual painting area is larger than the projected painting area, meaning that the apparent painting capacity per unit time is relatively low. Therefore, in this type of electrostatic atomization painting mechanism 50, the amount of paint discharged from the electrostatic atomization nozzle 52 is increased to obtain the desired coating thickness.

[0071] The control mechanism may be configured to perform the above-mentioned control based on shape data of the exterior panel surface measured immediately before painting while transporting the body 100. The control mechanism may be configured to perform the above-mentioned control based on shape data of the exterior panel surface measured at the time of designing the body 100.

[0072] The control mechanism may perform each control for each shaft mechanism 40 or each electrostatic atomization nozzle 52, or may perform each control for each group of a predetermined number of adjacent shaft mechanisms 40 or for each group of electrostatic atomization nozzles 52. Furthermore, when multiple rows of electrostatic atomization nozzles 52 are arranged in the electrostatic atomization coating mechanism 50, the control mechanism may perform each control for each row of the electrostatic atomization nozzles 52, or when multiple rows of electrostatic atomization coating mechanisms 50 are arranged, the control mechanism may perform each control for each row of the electrostatic atomization coating mechanisms 50.

[0073] As shown in FIG. 9, when the shaft mechanisms 40 are arranged in multiple rows back and forth in the X direction, it becomes possible to paint the same exterior panel surface multiple times.

[0074] In addition, as shown in FIG. 9, when the shaft mechanisms 40 are arranged in a plurality of rows with a half-pitch shift between adjacent rows, there is a margin for arranging adjacent electrostatic atomization coating mechanisms 50, and the risk of the adjacent electrostatic atomization coating mechanisms 50 coming into contact with each other when the electrostatic atomization coating mechanisms 50 are rotated can be avoided. In this case, when the gate mechanism is viewed along the conveying path, the ends of the electrostatic atomization nozzles 52 of the adjacent electrostatic atomization coating mechanisms 50 are arranged so as to overlap with each other, so that there is no area between the adjacent electrostatic atomization coating mechanisms 50 where painting cannot be performed. For example, there is no area between the electrostatic atomization coating mechanism 50 located closest to the penetrating portion 32 in the column portion 31 and the electrostatic atomization coating mechanism 50 located closest to the penetrating portion 32 in the penetrating portion 32 where painting cannot be performed.

[0075] Alternatively, the shaft mechanisms 40 may be arranged in a row along the Z direction in the column portion 31, and the shaft mechanisms 40 may be arranged in a row along the Y direction in the through portion 32. In this case, the row of the shaft mechanisms 40 in the column portion 31 and the row of the shaft mechanisms 40 in the through portion 32 may be arranged so as to coincide with each other. The row of the shaft mechanisms 40 in the column portion 31 and the row of the shaft mechanisms 40 in the through portion 32 may be arranged so as to be shifted in the X direction. Furthermore, the shaft mechanisms 40 may be arranged in two rows along the Z direction in the column portion 31, and the shaft mechanisms 40 may be arranged in two rows along the Y direction in the through portion 32. In this case, the shaft mechanisms 40 may be arranged so that the pitches of adjacent rows are the same, or so that the pitches are shifted.

[0076] In the above embodiment, the electrostatic atomization coating mechanisms 50 are identical in configuration, but this is not limited thereto. The electrostatic atomization coating mechanisms 50 may be different in configuration. For example, the electrostatic atomization coating mechanisms 50 may differ in the number of electrostatic atomization nozzles 52 or in the arrangement pattern.

[0077] For example, in an electrostatic atomization coating mechanism 50 that paints exterior panel surfaces of the body 100 with small curvatures, such as the hood or roof, it is considered that a large number of electrostatic atomization nozzles 52 are arranged, whereas in an electrostatic atomization coating mechanism 50 that paints exterior panel surfaces of the body 100 with large curvatures, such as the fenders, it is considered that a small number of electrostatic atomization nozzles 52 are arranged.

[0078] When the exterior panel surface to be coated is curved as viewed from the transport direction of the body 100, the actual coating area is larger than the projected coating area, i.e., the apparent coating capacity per unit time is relatively low, so that in such an electrostatic atomization coating mechanism 50, a large number of electrostatic atomization nozzles 52 are arranged in the direction along the transport direction. Alternatively, multiple rows of electrostatic atomization coating mechanisms 50 are arranged in the gate mechanism 30 along the transport direction.

[0079] Although the present invention has been described above with reference to the drawings, the present invention is not limited to the configurations shown in the drawings. Furthermore, it goes without saying that the present invention can be embodied in various forms without departing from the spirit and scope of the present invention. [Industrial Applicability]

[0080] The coating system according to the present invention can be particularly suitably used in technical fields in which painting is performed on the bodies of automobiles, railway vehicles, aircraft, etc., or in general industry. [Explanation of symbols]

[0081] 10:Painting system 20: Conveyor mechanism 30: Gate mechanism 31:Column part 32: Kanbe 40: Shaft mechanism 41: Cylinder 42: Rod 43:Support mechanism 50: Electrostatic atomization painting mechanism 51: Nozzle head 52: Electrostatic atomizing nozzle 53: Needle electrode 100: Body (substrate)

Claims

1. A coating system for coating an exterior surface of an object to be coated while conveying the object along a predetermined conveying path, comprising: a gate mechanism including a pair of pillars arranged across the transport path and a through portion provided across the pillars; A plurality of electrostatic atomization coating mechanisms, each of which has a plurality of electrostatic atomization nozzles arranged in parallel; a plurality of shaft mechanisms arranged in a row on the column portion and the through portion and supporting each of the electrostatic atomization coating mechanisms individually; The electrostatic atomization coating mechanism has a nozzle head made of a non-conductive material or a weakly conductive material, Each of the shaft mechanisms is configured to be capable of adjusting the coating distance of the electrostatic atomization coating mechanism supported by each of the shaft mechanisms from the surface of the exterior panel to be coated, and is configured to be capable of disposing each of the electrostatic atomization coating mechanisms so as to coat the entire surface or a part of the surface of the exterior panel to be coated when the gate mechanism is viewed along the transport path; A painting system characterized in that the row of shaft mechanisms in the column portion and the row of shaft mechanisms in the through portion are shifted forward and backward along the conveying path.

2. The painting system described in Claim 1, characterized in that each shaft mechanism is arranged in a single row when the gate mechanism is viewed in a direction perpendicular to the conveying path in each of the column portions and the through portions, or in multiple rows in the fore-and-aft direction of the conveying path, with the pitch of adjacent rows being the same or shifted.

3. The coating system according to claim 2, characterized in that each of the shaft mechanisms is arranged in multiple rows in the front-to-rear direction of the transport path in each of the column portions and the through portions, with adjacent rows being shifted by a half pitch, and is arranged such that portions of the ends of the multiple electrostatic atomization nozzles possessed by each of adjacent electrostatic atomization coating mechanisms overlap when the gate mechanism is viewed along the transport path.

4. The coating system according to any one of claims 1 to 3, characterized in that the shaft mechanism supports the electrostatic atomization coating mechanism so as to be rotatable at least around an axis along the conveying path or around an axis perpendicular to the conveying path.

5. The coating system according to any one of claims 1 to 4, characterized in that the gate mechanism is configured to be at least movable along the transport path or to be able to change its posture with respect to the exterior panel surface to be coated.

6. A control mechanism is provided for controlling the coating system; The painting system described in any one of claims 1 to 5, characterized in that the control mechanism is configured to be able to individually control each of the shaft mechanisms based on shape data of the exterior panel surface of the workpiece at the time of design, shape data of the exterior panel surface of the workpiece measured before the workpiece is transported, or shape data of the exterior panel surface of the workpiece measured immediately before painting while the workpiece is being transported.

7. A control mechanism is provided for controlling the coating system; 7. The coating system according to claim 1, wherein the control mechanism is configured to be capable of controlling the discharge of paint from each of the electrostatic atomization nozzles or each of the electrostatic atomization coating mechanisms based on shape data of the exterior panel surface of the object to be coated at the time of design, shape data of the exterior panel surface of the object to be coated measured before the object to be coated is transported, or shape data of the exterior panel surface of the object to be coated measured immediately before painting while the object to be coated is being transported.

8. A control mechanism is provided for controlling the coating system; The painting system described in any one of claims 1 to 7, characterized in that the control mechanism is configured to be able to identify the position and orientation of the workpiece on the transport path based on characteristic points of the outer panel coating surface of the workpiece and reference points defined on the transport path.

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