JP7628060B2 - Painting System - Google Patents

Description

The present invention relates to a painting system that paints the exterior surface of an object while transporting the object along a predetermined transport path.

Conventionally, in painting systems for painting objects such as automobiles, railway vehicles, and aircraft, the object is transported along a predetermined transport path in a painting room, and the object is painted using spray mechanisms supported by multiple robot arms arranged along the transport path.

The robot arm in question may be an orthogonal two-axis type, an orthogonal three-axis type, or a multi-joint six-axis type (see Patent Document 1).

Special Publication No. 2012-506305

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 painted. Furthermore, conventional painting systems were configured to install multiple robot arms along the transport path, which tended to make the painting booth long.

The present invention was made in consideration of the above situation, and aims to provide a painting system that can improve the coating efficiency and shorten the length of the painting booth when painting the workpiece while transporting it.

a gate mechanism having a pair of pillars arranged at a position straddling 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 a row on the pillars and the through portion; and a plurality of shaft mechanisms arranged in a row on the pillars and the through portion and individually supporting each of the electrostatic atomization coating mechanisms, each of which has a nozzle head formed of a non-conductive or weakly conductive material, each of the shaft mechanisms is configured to be able to adjust the coating distance of the electrostatic atomization coating mechanism that it supports from the exterior panel surface, and each of the electrostatic atomization coating mechanisms is configured to be able to be positioned so that, when the gate mechanism is viewed along the transport path, the electrostatic atomization coating mechanisms can be painted all or part of the exterior panel surface, and the row of shaft mechanisms at the pillars and the through portion are shifted forwards and backwards along the transport path .

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.

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

The electrostatic atomizing nozzle of the electrostatic atomizing coating mechanism does not use compressed air to atomize the paint, and therefore paint is less likely to splash around due to the lack of air currents generated by the electrostatic atomizing nozzle around the workpiece. This results in better coating efficiency than electrostatic atomizing nozzles such as rotary atomizing nozzles. However, as the amount of paint discharged per given time is small, the electrostatic atomizing nozzle has been limited in its application to painting small parts, etc.

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 and to install multiple robot arms along the transport direction, which increases the time and transport distance required for painting.

The optimal painting distance for the electrostatic atomization painting mechanism from the exterior panel surface is close to 50 to 120 mm, and in order to achieve a uniform coating thickness, the electrostatic atomization painting mechanism must be positioned at an appropriate painting distance from the exterior panel surface. For example, if the exterior panel surface of the workpiece has a complex shape, the position of the electrostatic atomization painting mechanism must be changed to match the changes in the shape of the exterior panel surface as it passes through the gate mechanism.

With the above-mentioned configuration, each electrostatic atomization painting mechanism is 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 painted, i.e., any desired location, from an appropriate painting distance that provides good coating efficiency. This means that the entire surface can be painted with high quality by simply passing the workpiece through the gate mechanism once, thereby shortening the length of the painting booth.

According to the present invention, it is possible to reduce the length of the painting booth to up to 1/15 compared to conventional painting systems that use rotary atomizing nozzles supported by a robot arm for painting.

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 amount of intake and exhaust required for the coating can be reduced to a maximum of 1/150 of the amount of intake and exhaust required for coating using a rotary atomizing nozzle attached to an articulated robot. This simplifies the need for the large-scale intake and exhaust equipment required in conventional coating systems to exhaust paint mist that has not been applied to the workpiece from the coating room, as well as the recovery equipment for recovering the exhausted paint mist.

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

Each electrostatic atomization coating mechanism may have the same configuration or different configurations. For example, if each electrostatic atomization coating mechanism has a different configuration, it is possible to vary the number of electrostatic atomization nozzles and the arrangement pattern of each electrostatic atomization coating mechanism. 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.

For example, if the object to be coated is the body of an automobile, a greater number of electrostatic atomization nozzles may be configured in an electrostatic atomization coating mechanism that corresponds to areas of the exterior coating surface with a smaller curvature (e.g., the bonnet or roof), while a smaller number of electrostatic atomization nozzles may be configured in an electrostatic atomization coating mechanism that corresponds to areas with a larger curvature (e.g., the fenders).

In other words, when the surface of the exterior panel to be painted is curved, if there are too many electrostatic atomizing nozzles arranged, all of the electrostatic atomizing nozzles cannot simultaneously maintain the optimal painting distance from the exterior panel surface, so in this type of electrostatic atomizing painting mechanism, the number of electrostatic atomizing nozzles arranged in the direction along the conveying direction is set to be small, and painting quality can be ensured. Note that when the surface of the exterior panel to be painted is inclined, the actual painting area is large compared to the projected painting area, meaning that the apparent painting capacity per unit time is relatively low, so in this type of 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 painting quality can be ensured.

In the present invention, the gate mechanism includes a pair of pillars arranged on either side of the transport path and a through portion provided across the pair of pillars, and the shaft mechanisms are preferably arranged so that they form a single row when the gate mechanism is viewed in a direction perpendicular to the transport path at each of the pillars and the through portion, or are arranged in multiple rows in the front-to-rear direction of the transport path, with the pitches of adjacent rows matching or shifting.

For example, if each shaft mechanism is arranged in a row, the dimensions of the gate mechanism in the transport direction of the workpiece can be made compact.

In addition, if the shaft mechanisms are arranged in multiple rows in the forward and backward directions of the transport path, the entire surface of the workpiece can be painted multiple times by simply passing the workpiece through the gate mechanism once.

In addition, 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 to prevent the adjacent electrostatic atomization spray mechanisms from coming into contact with each other.

In the present invention, it is preferable that the shaft mechanisms are arranged in multiple rows in the front-to-rear direction of the transport path in each of the pillars and the through-holes, with adjacent rows offset by a half-pitch, and that the ends of the multiple electrostatic atomization nozzles of adjacent electrostatic atomization coating mechanisms overlap when the gate mechanism is viewed along the transport path.

Since each shaft mechanism is arranged in multiple rows with a half-pitch offset between adjacent rows, there is ample space between 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, since the ends of the multiple electrostatic atomization nozzles of adjacent electrostatic atomization coating mechanisms are arranged so that they partially overlap when the gate mechanism is viewed along the transport path, there is no area between 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 pillar section and the electrostatic atomization coating mechanism located closest to the pillar section in the cross section where painting cannot be performed. It is preferable that the row in the pillar section and the row in the cross section are offset from each other in the front-to-rear direction of the transport path.

In the present invention, it is preferable that the shaft mechanism supports the electrostatic atomization coating mechanism so that it can rotate at least around an axis that is aligned with the transport path, or around an axis that is perpendicular to the transport path.

To achieve a uniform coating thickness, the electrostatic atomization coating mechanism must be positioned directly opposite the exterior panel surface. For example, if the exterior panel surface of the workpiece has a complex shape, the position of the electrostatic atomization coating mechanism must be changed to match the change in shape of the exterior panel surface as it passes through the gate mechanism. With the above-mentioned configuration, in an electrostatic atomization coating mechanism that does not face the exterior panel surface, the shaft mechanism can rotate the electrostatic atomization coating mechanism about an axis that runs along the transport path or about an axis that is perpendicular to the transport path, thereby ensuring coating quality.

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 coating surface.

When the object to be painted is, for example, the body of an automobile, it is necessary to paint the front and rear. Even if the movable range for rotating the electrostatic atomization painting mechanism by the shaft mechanism is not large, 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.

In the present invention, a control mechanism is provided to control the painting system, and the control mechanism is preferably configured to be able to individually control each of the shaft mechanisms based on shape data of the exterior surface of the workpiece at the time of design, shape data of the exterior surface of the workpiece measured before the workpiece is transported, or shape data of the exterior surface of the workpiece measured immediately before painting while the workpiece is being transported.

Depending on the shape of the exterior panel surface of the workpiece, the optimal painting distance and painting posture differs even for adjacent electrostatic atomization painting mechanisms, so as described above, the control mechanism 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.

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.

In the present invention, a control mechanism is provided for controlling the painting system, and the control mechanism is preferably configured to be capable of controlling the discharge of paint from each of the electrostatic atomizing nozzles or each of the electrostatic atomizing painting 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.

Each electrostatic atomizing nozzle and each electrostatic atomizing coating mechanism can control the discharge, so the coating thickness can be made uniform or uneven, and the spray pattern can be freely changed.

For example, when the electrostatic atomization coating mechanism is rotated when the shape of the exterior panel surface to be coated is not flat, the coating areas of adjacent electrostatic atomization coating mechanisms may overlap, and if paint is sprayed 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 sprayed from the electrostatic atomization nozzle or electrostatic atomization coating mechanism that sprays paint to the overlapping areas among the electrostatic atomization nozzles of at least one of the electrostatic atomization coating mechanisms can be reduced or stopped, or the coating area can be controlled by controlling the voltage applied by the needle electrode, thereby making the coating thickness uniform even in the overlapping areas, and maintaining the coating quality.

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. Note that 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.

In addition, 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 amount of paint discharged from the electrostatic atomization nozzle or electrostatic atomization painting mechanism in the direction along the conveying direction can be increased to ensure painting quality.

At the edge of the exterior panel of the workpiece, there may be no exterior panel surface to be painted by the electrostatic atomizing nozzle or electrostatic atomizing coating mechanism. In such cases, the electrostatic atomizing nozzle or electrostatic atomizing coating mechanism can be put into a non-discharge state to avoid wasting paint.

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

In the present invention, a control mechanism is provided to control 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.

The above-mentioned configuration allows the actual position and orientation of the workpiece on the transport path to be identified, allowing the shaft mechanism to be controlled with high precision.

FIG. 1 is a front view of a painting system according to the present invention. FIG. 2 is a side view of the painting system shown in FIG. 1 . FIG. 2 is a plan view of the painting system shown in FIG. 1 . An explanatory diagram of the front of the body and painting. 5 is an explanatory diagram of the extension and contraction of the shaft mechanism and the rotation of the electrostatic atomization coating mechanism. FIG. 5 is an explanatory diagram of the extension and contraction of the shaft mechanism and the rotation of the electrostatic atomization coating mechanism. FIG. FIG. 2 is an explanatory diagram of an electrostatic atomization coating mechanism. FIG. 11 is an explanatory diagram of an electrostatic atomization coating mechanism according to another embodiment. FIG. 11 is an explanatory diagram of a gate mechanism according to another embodiment.

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 direction in which the body 100 is transported is defined as the X direction, the direction perpendicular to the transport direction of the body 100 in a horizontal plane is defined as the Y direction, and the direction perpendicular to the transport direction of the body 100 in a vertical plane is defined as the Z direction.

The painting system 10 includes a conveyor mechanism 20 that transports the 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 number of shaft mechanisms 40 that are arranged on the gate mechanism 30, a number of electrostatic atomization painting mechanisms 50 that are supported by each shaft mechanism 40, and a control mechanism that controls the painting system 10.

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 through 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). The gate mechanism 30 may be configured to be rotatable around the lower ends of the pillars 31, or the through portion 32 may be configured to be movable up and down along the pillars 31.

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 looking at the gate mechanism 30 along the transport path of the conveyor mechanism 20.

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

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 also 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.

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 exterior coating surface of the body 100 by moving the rod 42 forward and backward relative to the cylinder 41.

This allows each electrostatic atomization coating mechanism 50 to paint from an appropriate distance for good coating efficiency, for example, from a position 50 to 120 mm from the exterior panel surface to be coated.

Furthermore, the shaft mechanism 40 has 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.

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 around an axis along the X direction (see FIG. 5) and around 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.

This allows the shaft mechanism 40 to place the electrostatic atomization coating mechanism 50 in an appropriate painting 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 is not directly facing the exterior panel surface of the body 100, so that it can be rotated to face the exterior panel surface.

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

The electrostatic atomization coating mechanism 50 includes a nozzle head 51, a number of electrostatic atomization nozzles 52 arranged in a line on the nozzle head 51, a paint supply mechanism that supplies paint to each electrostatic atomization nozzle 52, the voltage application mechanism that applies a potential difference between each nozzle head 51 and the exterior panel surface to be painted, the switching mechanism that 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.

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

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

The nozzle head 51 is made of a non-conductive or weakly conductive material, which prevents discharge between the nozzle head 51 and other objects even if the nozzle head 51, to which a high voltage is applied by the voltage application mechanism, unexpectedly comes close to another object.

The paint supply mechanism is configured to include 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 the electrostatic atomization nozzle 52. The supply pump supplies paint from the storage tank through the supply hose to the electrostatic atomization nozzle 52. The supply pump is configured to be able to adjust the amount of paint supplied.

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

By applying a high voltage (positive or negative voltage of 5 to 60 kV) using the voltage application mechanism, an electric field is formed around each electrostatic atomizer nozzle 52, and the charged paint ejected from each electrostatic atomizer nozzle 52 is atomized by the action of the electric field formed around each electrostatic atomizer nozzle 52 as a so-called 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.

In the electrostatic atomization coating mechanism 50, the paint ejected from the electrostatic atomization nozzle 52 flies along the electric field lines. By controlling the voltage applied by the needle electrode 53, the spray pattern can be controlled, making it possible to control the coating area.

The nozzle head 51 has 100 electrostatic atomizing nozzles 52 arranged at a pitch of 3 mm. Even if mutual interference of electric fields occurs between adjacent electrostatic atomizing nozzles 52, the electric field is formed uniformly without bias around the electrostatic atomizing nozzles 52. This results in uniform atomization of the charged paint sprayed from the electrostatic atomizing nozzles 52, improving the coating quality of the workpiece.

In addition, it effectively prevents the paint from adhering 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.

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

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

In addition, in three-dimensional measurement, it is possible to measure characteristic points of the coated exterior surface of the body 100 and reference points defined on the transport path, 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, so that the shaft mechanism 40 can be controlled with high accuracy. 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.

For example, when the electrostatic atomization coating mechanism 50 is 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 electrode 53, thereby making the coating thickness uniform even in the overlapping areas, and maintaining the coating quality.

In addition, at the end of the exterior panel surface of the body 100, there may be no exterior panel surface to be painted by the electrostatic atomizing nozzle 52 of the electrostatic atomizing coating mechanism 50. In such a case, the electrostatic atomizing nozzle 52 is put into a non-discharge state to avoid unnecessary consumption of paint.

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

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 the body 100 is being transported. 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.

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

As shown in FIG. 9, if the shaft mechanisms 40 are arranged in multiple rows back and forth in the X direction, multiple coatings can be applied to the same exterior panel surface.

In addition, as shown in FIG. 9, if the shaft mechanisms 40 are arranged in multiple rows with a half-pitch offset between adjacent rows, there is sufficient space between 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 transport path, the ends of the multiple electrostatic atomization nozzles 52 of the adjacent electrostatic atomization coating mechanisms 50 are arranged so that they overlap, 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 cross section 32 in the column section 31 and the electrostatic atomization coating mechanism 50 located closest to the column section 31 in the cross section 32.

In addition, the multiple shaft mechanisms 40 may be arranged in a row along the Z direction in the column 31, and the multiple 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 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 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 multiple shaft mechanisms 40 may be arranged in two rows along the Z direction in the column 31, and the multiple 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.

In the above embodiment, the electrostatic atomization coating mechanisms 50 are described as having the same configuration, but this is not limited to the above. The electrostatic atomization coating mechanisms 50 may have different configurations. For example, the electrostatic atomization coating mechanisms 50 may have different numbers of electrostatic atomization nozzles 52 or different arrangement patterns.

For example, in an electrostatic atomization coating mechanism 50 that paints exterior panel surfaces with small curvatures of the body 100 such as the hood and roof, it is possible to configure a large number of electrostatic atomization nozzles 52, and in an electrostatic atomization coating mechanism 50 that paints exterior panel surfaces with large curvatures of the body 100 such as the fenders, it is possible to configure a small number of electrostatic atomization nozzles 52.

When the exterior panel surface to be painted is curved as viewed from the transport direction of the body 100, the actual paint area is larger than the projected paint area, meaning that the apparent painting capacity per unit time is relatively low, so in such an electrostatic atomization painting 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 painting mechanisms 50 are arranged in the gate mechanism 30 along the transport direction.

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.

The coating system of the present invention can be particularly useful in technical fields such as painting the bodies of automobiles, railway vehicles, and aircraft, and in general industry.

10: Painting system 20: Conveyor mechanism 30: Gate mechanism 31: Pillar section 32: Through section 40: Shaft mechanism 41: Cylinder 42: Rod 43: Support mechanism 50: Electrostatic atomization painting mechanism 51: Nozzle head 52: Electrostatic atomization nozzle 53: Needle electrode 100: Body (subject to be painted)

Claims (8)

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 . 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 at each of the pillar portions and the through portions, or in multiple rows in the front-to-rear direction of the conveying path, with the pitch of adjacent rows being the same or shifted. The coating system according to claim 2, characterized in that the shaft mechanisms are arranged in multiple rows in the front-rear direction of the transport path in each of the pillars and the through-holes, with adjacent rows shifted by a half pitch, and are arranged such that, when the gate mechanism is viewed along the transport path, a portion of the ends of the multiple electrostatic atomization nozzles of each of the adjacent electrostatic atomization coating mechanisms overlap. 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 that it can rotate at least around an axis along the transport path or around an axis perpendicular to the transport path. 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. 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. 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. 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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