JP6815478B2 - Rotary atomization type coating machine - Google Patents

Description

The present invention relates to a rotary atomization type coating machine provided with a rotary atomizing head on the tip side of the main body of the coating machine, and particularly cleans the back surface of the rotary atomizing head by ejecting a cleaning agent and air from a cleaning nozzle. It relates to a rotary atomizing type coating machine having a function.

Since strict coating quality is required for coating automobile bodies and automobile parts, a rotary atomization type coating machine capable of performing uniform and high quality coating is used. This coating machine is equipped with a rotary atomizing head, and atomizes and sprays paint by the centrifugal force generated by rotating the rotary atomizing head.

By the way, in the painting line of the automobile body, automobile bodies having different painting colors are mixed and transported. Therefore, the rotary atomization type coating machine is configured so that color change coating can be performed according to the automobile body. Then, in the coating machine, when the color is changed from the previous color paint to the next color paint, color mixing is prevented by cleaning the paint remaining in the paint supply path in the coating machine with a cleaning agent. In that case, since the paint adheres not only to the front side of the rotary atomizing head to which the paint is supplied but also to the back side, it is required to clean the back side as well.

Under such circumstances, several structures for cleaning the back surface side of the rotary atomizing head have been conventionally proposed (for example, Patent Documents 1 and 2). For example, Patent Document 1 discloses a coating machine including a cleaning nozzle provided on the tip side of the coating machine main body and at a position eccentric from the central axis, and a cleaning solvent supply device for supplying the cleaning solvent to the cleaning nozzle. ing. In this coating machine, the cleaning nozzle is arranged on the tip side of the main body of the coating machine and at a position eccentric from the central axis. At the time of cleaning, the cleaning solvent is supplied from the cleaning solvent supply device to the cleaning nozzle, and the cleaning solvent is sprayed toward the back side of the rotary atomizing head. Further, Patent Document 2 discloses a coating machine in which shaping air having a predetermined pressure is ejected while the back surface side of the rotary atomizing head is being cleaned with a cleaning agent.

By the way, in a coating machine having such a cleaning structure, for example, cleaning agent and air are pressure-fed to a cleaning nozzle via a cleaning fluid supply path, and on the way, a path is blocked on the upstream side immediately near the cleaning nozzle. A valve may be provided. Such a valve plays a role of blocking the cleaning fluid supply path during non-cleaning to prevent the cleaning agent remaining in the path from leaking during painting. However, there is usually not enough space for arranging such a valve on the tip side of the coating machine body and at a position eccentric from the central axis. Therefore, it is necessary to use a valve having a small and simple structure. Specifically, a mode in which a check valve (check valve) having a valve body, a valve seat, and a urging means is used to urge the valve body toward the valve seat side against the forward flow of the cleaning fluid. It is considered suitable to install in.

Jitsukaisho 62-48458 Japanese Patent No. 3346146

However, when the cleaning fluid supply path is blocked by such a check valve, the cleaning agent and air remain in the area upstream of the check valve in the cleaning fluid supply path in a somewhat pressurized state. .. Moreover, when the check valve is installed in the above-described manner, the urging force of the urging means cannot be set so large in order to allow the cleaning fluid to flow smoothly during cleaning. Therefore, due to the structure, it is difficult to seal the cleaning fluid supply path with high sealing properties. Therefore, if the residual pressure in the cleaning fluid supply path is high, the cleaning agent and air in the upstream region of the check valve are released to the downstream side when the sealability of the check valve deteriorates due to vibration or the like. Then, due to the influence, the cleaning agent remaining in the path leaks from the cleaning nozzle. As a result, there is a problem that the risk of the cleaning agent falling on the surface of the object to be coated increases, and coating defects are likely to occur.

The present invention has been made in view of the above problems, and an object of the present invention is to surely prevent leakage of a cleaning agent from a cleaning nozzle during painting, and to prevent the occurrence of painting defects caused by the leakage. The purpose is to provide a rotary atomizing coating machine that can.

In order to solve the above problems, the invention described in the means 1 is applied to the main body of the coating machine, the rotary atomizing head provided on the tip side and the central axis of the main body of the painting machine, and the back surface of the rotary atomizing head. A cleaning nozzle arranged at the tip side of the coating machine main body and at a position eccentric from the central axis in order to eject cleaning agent and air as a cleaning fluid toward the cleaning fluid, and a cleaning agent supply path and air at the start of the path. The supply path is connected, and the cleaning fluid supply path for supplying the cleaning agent and the air to the cleaning nozzle located at the end of the path and the cleaning fluid supply path in the middle of the cleaning fluid supply path in order to block the cleaning fluid supply path during non-cleaning. A rotary atomization type coating machine equipped with a check valve arranged separately from the cleaning nozzle on the upstream side immediately above the cleaning nozzle, wherein the check valve has a valve body, a valve seat, and an urging. The urging means is configured to urge the valve body to the valve seat side against the forward flow of the cleaning fluid, and the urging force of the urging means is the cleaning at the time of cleaning. It is characterized in that it is preset to be smaller than the fluid supply pressure and is provided with a residual pressure reduction mechanism that reduces the residual pressure in the upstream region of the check valve in the cleaning fluid supply path. The gist is a rotary atomizing type coating machine.

Therefore, according to the invention described in the means 1, as a result of the residual pressure in the upstream region of the check valve in the cleaning fluid supply path being reduced by the residual pressure reducing mechanism, the urging force of the urging means is higher than the pressure in the upstream region. Is relatively large. Therefore, even if a check valve having a low sealing property is used, the cleaning fluid supply path is surely sealed. Therefore, the leakage of the cleaning agent from the cleaning nozzle during painting is surely prevented, and the occurrence of painting defects caused by the leakage is prevented.

According to the invention described in the means 2, in the means 1, the residual pressure reducing mechanism is connected to the upstream region of the check valve in the cleaning fluid supply path, and the cleaning remaining in the upstream region of the check valve. The gist is that the structure includes a relief path for releasing the fluid from the cleaning fluid supply path and releasing the fluid at a position away from the main body of the coating machine.

Therefore, according to the invention described in the means 2, as a result of the cleaning fluid remaining in the upstream region of the check valve being released via the escape path, the residual pressure is released at a position away from the main body of the coating machine. Therefore, the residual pressure in the upstream region can be reliably released. Further, since the remaining cleaning fluid is released to a position away from the object to be coated, the risk of the cleaning agent adhering to the object to be coated can be minimized.

According to the invention described in the means 3, in the means 2, the residual pressure reducing mechanism further includes a residual pressure reducing valve provided at a connection portion between the relief path and the cleaning fluid supply path. The summary is.

Therefore, according to the invention described in the means 3, when the residual pressure reduction valve is in the closed state, the relief path and the cleaning fluid supply path are cut off. On the other hand, when the residual pressure reduction valve is in the open state, the relief path and the cleaning fluid supply path are communicated with each other, and the cleaning fluid remaining in the upstream region of the check valve is released via the release path. Therefore, the residual pressure can be released in a timely manner by controlling the valve.

According to the invention described in the means 4, in the means 3, a cleaning agent supply valve is provided at a connection portion between the cleaning agent supply path and the cleaning fluid supply path, and the air supply path and the cleaning fluid supply path are provided. The gist is that an air supply valve is provided at the connection portion, and the cleaning agent supply valve, the air supply valve, and the residual pressure reduction valve are installed on a common manifold block.

Therefore, according to the invention described in the means 4, when the cleaning agent supply valve is in the open state, the cleaning agent supply path and the cleaning fluid supply path are communicated with each other, and the cleaning agent is supplied into the cleaning fluid supply path. As a result, the cleaning agent is ejected from the cleaning nozzle, and the back side of the rotary atomizing head is cleaned. On the other hand, when the air supply valve is in the open state, the air supply path and the cleaning fluid supply path are communicated with each other, and air is supplied into the cleaning fluid supply path. As a result, the cleaning agent remaining in the cleaning fluid supply path is blown off and ejected from the cleaning nozzle together with air. Further, since the cleaning agent supply valve, the air supply valve, and the residual pressure reduction valve are installed on the common manifold block, the piping for connecting these valves to each other can be omitted. Therefore, the device can be configured compactly.

According to the invention described in the means 5, in the means 3, a cleaning agent supply valve is provided at a connection portion between the cleaning agent supply path and the cleaning fluid supply path, and the cleaning agent supply valve is provided in the cleaning fluid supply path. An air supply valve is provided on the upstream side portion, and the air supply path and the relief path are connected to the air supply valve, and the cleaning agent supply valve and the air supply valve are the residual pressure reduction valve. The gist is that it also functions as a valve.

Therefore, according to the invention described in the means 5, it is not necessary to provide a residual pressure reduction valve separately from the cleaning agent supply valve and the air supply valve, so that the device can be compactly configured.

The gist of the invention described in the means 6 is that, in any one of the means 2 to 5, the cleaning agent in the relief path is pumped by using the air from the air supply path.

If the cleaning agent accumulates in the relief path, the passage resistance when the cleaning agent escapes increases, and the accumulated cleaning agent may flow back to the cleaning fluid supply path side, so the efficiency of releasing the residual pressure May decrease. In that respect, according to the invention described in the means 6, since the cleaning agent in the relief path is pumped and discharged using the air from the air supply path, the cleaning agent is less likely to accumulate in the relief path. Therefore, it is possible to prevent an increase in the passage resistance of the cleaning agent and prevent the backflow of the accumulated cleaning agent. Therefore, the residual pressure can be reliably released for a long period of time.

The invention described in the means 7 includes a control device for driving and controlling valves in the means 4 or 5, and the control device is used for a predetermined time during the period from immediately before the end of the cleaning period to the start of the painting period. The gist is to perform residual pressure reduction control that opens the residual pressure reduction valve.

Therefore, according to the invention described in the means 7, the residual pressure reduction valve of the control means is opened for a predetermined time during the period from the end of the cleaning period to the start of the painting period. Therefore, the residual pressure is reduced at that timing.

The invention described in the means 8 includes a control device for driving and controlling valves in the means 4 or 5, and the cleaning agent in the relief path is pressure-fed using the air from the air supply path. The control device is in the path of keeping the cleaning agent supply valve in the closed state, opening the air supply valve for a predetermined time, and opening the residual pressure reducing valve during the period excluding the coating period. The gist is to control the discharge of cleaning agents.

Therefore, according to the invention described in the means 8, the cleaning agent discharge control in the path of the control means opens the air supply valve for a predetermined time while keeping the cleaning agent supply valve closed during the period excluding the painting period. The state is set and the residual pressure reduction valve is opened. Then, as a result of air being supplied from the air supply valve to the residual pressure reduction valve at that timing, the cleaning agent in the relief path is pressure-fed using the air and discharged.

The gist of the invention described in the means 9 is that, in any one of the means 1 to 8, the coating machine main body is supported by the tip of the robot arm.

When the coating machine body is supported by the robot arm and used, the vibration generated by the movement of the arm is likely to be applied to the coating machine body, so that the sealability of the check valve is usually likely to deteriorate, and the residual cleaning agent. Increases the risk of leaking out of the cleaning nozzle. In that respect, according to the invention described in the means 9 provided with the residual pressure reducing mechanism, even when the coating machine main body is supported by the robot arm and used, the cleaning agent leak from the cleaning nozzle is surely prevented, which is the cause. The occurrence of painting defects is prevented.

As described in detail above, according to the inventions of claims 1 to 9, it is possible to reliably prevent the cleaning agent from leaking from the cleaning nozzle during painting, and prevent the occurrence of painting defects caused by the leakage. A rotary atomizing type coating machine capable of being provided can be provided.

The schematic diagram which shows the rotary atomization type coating machine of 1st Embodiment which embodied this invention. The main part enlarged sectional view which shows the coating machine main body of the rotary atomization type coating machine of 1st Embodiment. The schematic diagram for demonstrating the valves constituting the residual pressure reduction mechanism in the rotary atomization type coating machine of 1st Embodiment. The figure for demonstrating the timing of performing the residual pressure reduction control. The figure for demonstrating the timing of performing the residual pressure reduction control. The figure for demonstrating the timing which performs the residual pressure reduction control and the cleaning agent discharge control in a path. The figure for demonstrating the timing which performs the residual pressure reduction control and the cleaning agent discharge control in a path. The figure for demonstrating the timing which performs the residual pressure reduction control and the cleaning agent discharge control in a path. The schematic diagram for demonstrating the valves constituting the residual pressure reduction mechanism in the rotary atomization type coating machine of 2nd Embodiment.

[First Embodiment]
Hereinafter, an embodiment in which the present invention is embodied in a rotary atomization type coating machine will be described in detail with reference to FIGS. 1 to 8.

As shown in FIG. 1, the rotary atomization type coating machine 1 of the present embodiment is, for example, an electrostatic coating machine for painting an automobile body, and a coating machine main body 11 is supported by the tip of a robot arm 2. It has a structure. In the rotary atomization type coating machine 1, the control device 3 drives and controls the robot arm 2, so that the spraying direction and position of the paint sprayed from the tip side of the coating machine main body 11 are changed.

As shown in FIGS. 1 and 2, the rotary atomization type coating machine 1 includes a tubular coating machine main body 11 and a hollow tubular portion 13 rotated by an air motor 12 provided in the coating machine main body 11. A rotary atomizing head 14 (bell cup) provided at the tip of the tubular portion 13 and a metal feed tube 15 extending in the tubular portion 13 in the axial direction thereof are provided. The tubular portion 13 is formed in a cylindrical shape, and the feed tube 15 is arranged in the tubular portion 13 so as not to come into contact with the inner surface thereof. Further, the rotary atomizing head 14 is a cup-shaped member, and is provided on the tip end side of the coating machine main body 11 and on the central shaft 16.

The feed tube 15 is formed with a common supply path for selectively supplying the paint and the cleaning agent to the front surface 18 of the rotary atomizing head 14. A paint supply device 17 is connected to the base end side of the feed tube 15. The paint supply device 17 is housed behind the air motor 12 in the coating machine main body 11. The paint supply device 17 is configured to discharge a predetermined amount of paint or cleaning agent to the supply path of the feed tube 15 based on the control signal of the control device 3. Specifically, the paint supply device 17 includes valves, pipes, and the like for switching the supplied paint to a different color paint or switching from the paint to a cleaning agent. Further, the paint supply device 17 includes a pump or the like for adjusting the discharge amount of the paint or the cleaning agent. Further, the coating machine main body 11 is provided with a high voltage generator (not shown) as a voltage applying means for generating a high voltage (for example, −90 kV) for applying to the rotary atomizing head 14. A high voltage is applied to the rotary atomizing head 14 by this high voltage generator, and the paint particles atomized by the rotary atomizing head 14 are sprayed in a charged state.

Next, the cleaning structure on the back surface 18 side of the rotary atomizing head and the residual pressure reducing mechanism Z1 in the present embodiment will be described.

As shown in FIG. 1 and the like, the rotary atomization type coating machine 1 basically includes a cleaning fluid supply path 21, a cleaning agent supply path 22, and an air supply path 23. The cleaning fluid supply path 21 extends from the side surface of the forearm portion of the robot arm 2 to the inside of the coating machine main body 11 at the tip end portion. On the other hand, the cleaning agent supply path 22 is a path for supplying cleaning agent such as thinner to the cleaning fluid supply path 21, and extends from the base end side of the robot arm 2 to the side surface of the forearm portion. There is. The air supply path 23 is a path for supplying pressurized air to the cleaning fluid supply path 21, and similarly extends from the base end side of the robot arm 2 to the side surface of the forearm portion. .. At the position of the side surface of the forearm, the cleaning agent supply path 22 and the air supply path 23 are connected to the path start end E2 of the cleaning fluid supply path 21 in a flow path.

As shown in FIGS. 1 and 2, the cleaning nozzle 26 is arranged on the tip side of the coating machine main body 11 and at a position eccentric from the central axis 16 with the tip facing the back surface 18 of the rotary atomizing head 14. Has been done. The cleaning nozzle 26 is located at the path end E1 of the cleaning fluid supply path 21, and ejects a cleaning agent and air as a cleaning fluid toward the back surface 18 of the rotary atomizing head 14 for cleaning. A small check valve 31 is provided on the upstream side of the cleaning nozzle 26 in the middle of the cleaning fluid supply path 21.

As shown in FIG. 2, the check valve 31 of the present embodiment includes a valve body 32, a valve seat 33, and an urging means 34. The ball as the valve body 32 is housed in a state where it can move up and down in the internal space of the housing constituting the check valve 31. The valve seat 33 has a substantially conical shape and is formed on the inner wall surface on the upper side of the housing. The coil spring as the urging means 34 is housed under the valve body 32 in the internal space of the housing so as to urge the valve body 32 toward the valve seat 33 side against the positive flow of the cleaning fluid. It is configured. The urging force of the urging means 34 is set in advance so as to be smaller than the supply pressure of the cleaning fluid at the time of cleaning. Therefore, the cleaning fluid supply path 21 is blocked during non-cleaning when it is not necessary to supply the cleaning fluid. On the other hand, at the time of cleaning when it is necessary to supply the cleaning fluid, the cleaning fluid supply path 21 is opened, and the cleaning fluid and air which are the cleaning fluids are ejected from the cleaning nozzle 26.

Next, the residual pressure reduction mechanism Z1 of the present embodiment will be described. As shown in FIG. 3 and the like, the residual pressure reduction mechanism Z1 includes a cleaning agent supply valve 51, an air supply valve 61, a residual pressure reduction valve 71, a manifold block 81, a relief path 24, and the like. The cleaning agent supply valve 51, the air supply valve 61, and the residual pressure reduction valve 71 are installed on a common manifold block 81 provided on the side surface of the forearm portion of the robot arm 2.

The cleaning agent supply valve 51 of the present embodiment is a so-called normally closed type two-way valve, and is driven by the pilot air PA1. In the housing 52 constituting the cleaning agent supply valve 51, the valve body accommodating chamber 53 and the piston accommodating chamber 54 are formed in a state of communicating with each other through a communicating space. A piston 55 is housed in the valve body accommodating chamber 53 so as to be vertically movable, and the valve body accommodating chamber 53 is divided into two regions by the piston 55. The upper compartment region in FIG. 3 houses the coil spring 57 and communicates with the atmospheric pressure region. On the other hand, the lower compartment area in FIG. 3 communicates with the pilot port 41C provided on the side surface of the housing 52. A rod 56 is inserted and fixed in the center of the piston 55. The rod 56 passes through the communication space and reaches the valve body accommodating chamber 53, and the valve body 58 is integrally formed at the lower end portion thereof. An O-ring-shaped seal member 62 is provided on the upper side of the communication space, and a rod seal 60 is provided on the lower side of the communication space. The seal member 62 prevents the pilot air PA1 from leaking from the piston accommodating chamber 54 side to the valve body accommodating chamber 53 side via the communication space. The rod seal 60 prevents the cleaning agent and air introduced into the valve body accommodating chamber 53 side from leaking to the piston accommodating chamber 54 side through the communication space. The valve body accommodating chamber 53 communicates with the first port 41A provided on the side surface of the housing 52 and the second port 41B provided on the bottom surface of the housing 52, respectively. A ring-shaped valve seat 59 is provided on the lower side surface of the valve body accommodating chamber 53, and the lower end portion of the valve body 58 is brought into contact with and separated from the valve seat 59.

Then, in the cleaning agent supply valve 51 configured in this way, when the pilot air PA1 is not introduced into the pilot port 41C, the piston 55, the rod 56, and the valve body 58 move downward due to the urging force of the coil spring 57. As a result, the valve body 58 comes into contact with the valve seat 59, and the first port 41A and the second port 41B are blocked from each other in a closed state. On the other hand, when the pilot air PA1 is introduced into the pilot port 41C, the pilot air acts against the urging force of the coil spring 57, so that the piston 55, the rod 56, and the valve body 58 move upward. As a result, the valve body 58 is separated from the valve seat 59, and the first port 41A and the second port 41B are in an open state in which they communicate with each other.

The air supply valve 61 of the present embodiment is a normally closed type two-way valve including two ports 42A and 42B and one pilot port 42C, and is driven by the pilot air PA2. Further, the residual pressure reduction valve 71 of the present embodiment is a normally closed type two-way valve including two ports 43A and 43B and one pilot port 43C, and is driven by the pilot air PA3. There is. Since the air supply valve 61 and the residual pressure reduction valve 71 have basically the same structure as the cleaning agent supply valve 51, detailed description thereof will be omitted instead of assigning common member numbers to them.

A port 83 to which the cleaning fluid supply path 21 is connected is provided on the end surface of the manifold block 81. Inside the manifold block 81, a flow path 82 that communicates with the port 83 and branches in three directions is connected. The bottom side of the cleaning agent supply valve 51, the air supply valve 61, and the residual pressure reduction valve 71 are fixed on the manifold block 81, respectively. Then, the second port 41B at the bottom of the cleaning agent supply valve 51, the second port 42B at the bottom of the air supply valve 61, and the second port 43B at the bottom of the residual pressure reduction valve 71 are connected to the branched flow path 82, respectively. There is.

In the case of this residual pressure reduction mechanism Z1, the cleaning agent supply path 22 is connected to the first port 41A of the cleaning agent supply valve 51 via the check valve CK1, and the check valve is stopped at the first port 42A of the air supply valve 61. The air supply path 23 is connected via the valve CK1. Further, the relief path 24 is directly connected to the first port 43A of 81 of the residual pressure reduction valve 71.

Next, the operation of the residual pressure reduction mechanism Z1 configured in this way will be described.

FIG. 4 is a diagram showing a table for explaining the timing of performing residual pressure reduction control. In this table, P1 indicates the first coating period, P2 indicates the cleaning period, and P3 indicates the second coating period. In the table, the white part indicates that the valve is in the closed state, and the black part indicates that the valve is in the open state. In the first coating period P1, the cleaning agent supply valve 51, the air supply valve 61, and the residual pressure reduction valve 71 are all maintained in the closed state. Therefore, at this time, the cleaning agent is not supplied from the cleaning agent supply path 22, and the air is not supplied from the air supply path 23. Also, the escape route 24 does not communicate.

When the first coating period P1 is completed, the control device 3 outputs a signal to an electromagnetic valve (not shown) that controls the supply and discharge of pilot air, and first causes the pilot air PA1 to act on the pilot port 41C of the cleaning agent supply valve 51. .. Then, the cleaning agent supply valve 51 is switched from the closed state to the open state, and the cleaning agent is supplied from the cleaning agent supply path 22 to the cleaning fluid supply path 21 via the cleaning agent supply valve 51 and the manifold block 81. As a result, the cleaning agent is ejected from the cleaning nozzle 26, and cleaning of the back surface 18 side of the rotary atomizing head 14 is started.

After the elapse of a predetermined time, the control device 3 stops the supply of the pilot air PA1 to the pilot port 41C of the cleaning agent supply valve 51, and controls the pilot port 42C of the air supply valve 61 to act on the pilot air PA2. Then, the cleaning agent supply valve 51 switches from the open state to the closed state, and the supply of the cleaning agent from the cleaning agent supply path 22 is stopped. Instead, the air supply valve 61 is switched from the closed state to the open state, and air is supplied from the air supply path 23 to the cleaning fluid supply path 21 via the air supply valve 61 and the manifold block 81. As a result, the cleaning fluid in which the cleaning agent and air are mixed is discharged from the cleaning nozzle 26, the back surface 18 side of the rotary atomizing head 14 is cleaned, and the cleaning agent in the cleaning fluid supply path 21 is gradually aired. Is replaced with.

After the elapse of a predetermined time, the control device 3 stops the supply of the pilot air PA2 to the pilot port 42C of the air supply valve 61, and controls the pilot port 43C of the residual pressure reduction valve 71 to act on the pilot air PA3. Then, the air supply valve 61 is switched from the open state to the closed state, and the air supply from the air supply path 23 is stopped. Instead, the residual pressure reduction valve 71 switches from the closed state to the open state. As a result, in the cleaning fluid supply path 21, the upstream region of the check valve 31 and the residual pressure reduction path 24 are in a state of communicating with each other via the residual pressure reduction valve 71 and the manifold block 81. Therefore, the pressure remaining in the upstream region is released through the residual pressure reduction path 24.

After that, the control device 3 again controls to stop the supply of the pilot air PA3 to the pilot port 43C of the residual pressure reduction valve 71. Then, the residual pressure reduction valve 71 is switched from the open state to the closed state, and the cleaning period P2 ends. Then, after the lapse of such a cleaning period P2, the second coating period P3 is started.

The table of FIG. 5 is slightly different from the table of FIG. 4, and valve drive control may be performed at such a timing. Specifically, after the end of the first coating period P1, the control device 3 first controls the cleaning agent supply valve 51 to switch from the closed state to the open state. Then, as a result of the cleaning agent being supplied from the cleaning agent supply path 22 to the cleaning fluid supply path 21, the cleaning agent is ejected from the cleaning nozzle 26, and the back surface 18 side of the rotary atomizing head 14 is cleaned. After a lapse of a predetermined time, the control device 3 controls the air supply valve 61 to be switched from the closed state to the open state instead of switching the cleaning agent supply valve 51 from the open state to the closed state. As a result, the supply of the cleaning agent is stopped, and air is supplied to the cleaning fluid supply path 21. As a result, the cleaning fluid in which the cleaning agent and air are mixed is discharged from the cleaning nozzle 26, the back surface 18 side of the rotary atomizing head 14 is cleaned, and the cleaning agent in the cleaning fluid supply path 21 is gradually aired. Is replaced with. After that, the control device 3 controls to switch the air supply valve 61 from the open state to the closed state. As a result, the supply of air is stopped, and the cleaning period P2 ends. Then, after the lapse of such a cleaning period P2, the second coating period P3 starts. After a predetermined period has elapsed from the start of the second coating period P2, the control device 3 switches the residual pressure reduction valve 71 from the closed state to the open state. As a result, in the cleaning fluid supply path 21, the upstream region of the check valve 31 and the residual pressure reduction path 24 communicate with each other, and the pressure remaining there is released via the residual pressure reduction path 24. That is, the residual pressure reduction control may be performed immediately before the end of the cleaning period P2 (that is, by the start of the coating period P3) as in FIG. 4, and the cleaning period P2 is as in FIG. It may be done after finishing and entering the painting period P3.

Further, the residual pressure reduction operation and the in-path cleaning agent discharge operation may be realized by performing the valve drive control at the timing as shown in the table shown in FIG. Specifically, after the end of the first coating period P1, the control device 3 first controls the cleaning agent supply valve 51 to switch from the closed state to the open state to start the cleaning period. Then, as a result of the cleaning agent being supplied from the cleaning agent supply path 22 to the cleaning fluid supply path 21, the cleaning agent is ejected from the cleaning nozzle 26, and cleaning of the back surface 18 side of the rotary atomizing head 14 is started. After a lapse of a predetermined time, the control device 3 controls the cleaning agent supply valve 51 from the open state to the closed state, while the air supply valve 61 is switched from the closed state to the open state. As a result, the supply of the cleaning agent is stopped, and air is supplied to the cleaning fluid supply path 21. As a result, the cleaning fluid in which the cleaning agent and air are mixed is discharged from the cleaning nozzle 26, the back surface 18 side of the rotary atomizing head 14 is cleaned, and the cleaning agent in the cleaning fluid supply path 21 is gradually aired. Is replaced with. After that, the control device 3 controls to switch the residual pressure reduction valve 71 from the closed state to the open state while keeping the air supply valve 61 in the open state. As a result, the residual pressure is reduced while maintaining the supply of air to the cleaning fluid supply path 21. As a result, in the cleaning fluid supply path 21, the upstream region of the check valve 31 and the residual pressure reduction path 24 communicate with each other, and the pressure remaining there is released via the residual pressure reduction path 24. After that, the control device 3 controls to keep the residual pressure reduction valve 71 in the open state while switching the air supply valve 61 from the open state to the closed state. As a result, instead of stopping the supply of air to the cleaning fluid supply path 21, the air is introduced into the residual pressure reduction path 24. As a result, the cleaning agent remaining in the residual pressure reduction path 24 is blown off by the air, the cleaning agent is discharged from the residual pressure reduction path 24, and the cleaning period P2 ends. Then, after the lapse of such a cleaning period P2, the second coating period P3 starts.

Alternatively, the residual pressure reduction operation and the in-path cleaning agent discharge operation may be realized by performing the valve drive control at the timing as shown in the table shown in FIG. Specifically, after the end of the first coating period P1, the control device 3 first controls the cleaning agent supply valve 51 to switch from the closed state to the open state to start the cleaning period P2. Then, as a result of the cleaning agent being supplied from the cleaning agent supply path 22 to the cleaning fluid supply path 21, the cleaning agent is ejected from the cleaning nozzle 26, and cleaning of the back surface 18 side of the rotary atomizing head 14 is started. After a lapse of a predetermined time, the control device 3 controls to switch the air supply valve 61 and the residual pressure reduction valve 71 from the closed state to the open state instead of switching the cleaning agent supply valve 51 from the open state to the closed state. As a result, the supply of the cleaning agent is stopped, and air is supplied to the cleaning fluid supply path 21. As a result, the cleaning fluid in which the cleaning agent and air are mixed is discharged from the cleaning nozzle 26, the back surface 18 side of the rotary atomizing head 14 is cleaned, and the cleaning agent in the cleaning fluid supply path 21 is gradually aired. Is replaced with. At the same time, air is introduced into the residual pressure reduction path 24, the cleaning agent remaining there is blown off by the air, and the cleaning agent is discharged from the residual pressure reduction path 24. After that, the control device 3 controls to switch the residual pressure reduction valve 71 from the open state to the closed state while keeping the air supply valve 61 in the open state. As a result, the above-mentioned in-path cleaning agent discharging operation is stopped while maintaining the supply of air to the cleaning fluid supply path 21. At this time, as a result of the air being supplied to the cleaning fluid supply path 21, the air is mainly discharged from the cleaning nozzle 26. After that, the control device 3 controls the air supply valve 61 to be switched from the open state to the closed state and the residual pressure reduction valve 71 to be switched from the closed state to the open state. As a result, in the cleaning fluid supply path 21, the upstream region of the check valve 31 and the residual pressure reduction path 24 communicate with each other, and the pressure remaining there is released via the residual pressure reduction path 24 to reduce the residual pressure. .. After that, the control device 3 controls to switch the residual pressure reduction valve 71 from the open state to the closed state, stops the residual pressure reduction operation, and ends the cleaning period P2. Then, after the lapse of such a cleaning period P2, the second coating period P3 is started.

Alternatively, the residual pressure reduction operation and the in-path cleaning agent discharge operation may be realized by performing the valve drive control at the timing as shown in the table shown in FIG. Specifically, the residual pressure reduction operation is first performed at the timing as shown in the table of FIG. 4, and the cleaning period P2 is ended. Then, after the elapse of the cleaning period P2, the control device 3 then controls the air supply valve 61 and the residual pressure reduction valve 71 to be switched from the closed state to the open state while maintaining the cleaning agent supply valve 51 in the closed state. I do. As a result, air is introduced into the residual pressure reduction path 24, the cleaning agent remaining there is blown off by the air, and the cleaning agent is discharged from the residual pressure reduction path 24. After that, the control device 3 controls to switch the air supply valve 61 from the open state to the closed state while keeping the residual pressure reduction valve 71 in the open state. After the cleaning period P2 ends and a predetermined period elapses, the residual pressure reduction valve 71 is controlled to be switched from the open state to the closed state, and the in-path cleaning agent discharging operation is terminated. That is, the in-route cleaning agent discharge control can be performed at any timing during the period excluding the coating periods P1 and P2, and may be performed immediately before the end of the cleaning period P2 as in FIG. 6, for example. , It may be performed in the middle of the cleaning period P2 as in FIG. 7, or after the end of the cleaning period P2 as in FIG. 8 (that is, the interval period between the cleaning period P2 and the coating period P3). May be good.

Therefore, according to the present embodiment, the following effects can be obtained.

The rotary atomization type coating machine 1 of the present embodiment is provided with a residual pressure reducing mechanism Z1 for reducing the residual pressure in the upstream region of the check valve 31 in the cleaning fluid supply path 21. Therefore, the residual pressure reduction mechanism Z1 reduces the residual pressure in the upstream region of the check valve 31 in the cleaning fluid supply path 21. As a result, the urging force of the urging means 34 is relatively larger than the pressure in the upstream region. Therefore, even if the check valve 31 having a low sealing property is used, the cleaning fluid supply path 21 is surely sealed. Therefore, the leakage of the cleaning agent from the cleaning nozzle 26 during painting can be reliably prevented, and the occurrence of coating defects due to the leakage can be prevented.
(2) In the residual pressure reduction mechanism Z1 in the rotary atomization type coating machine 1 of the present embodiment, the cleaning fluid remaining in the upstream region of the check valve 31 is released via the escape path 24. As a result, the residual pressure is released at a position away from the coating machine main body 11. Therefore, the residual pressure in the upstream region can be reliably released. Further, since the remaining cleaning fluid is released to a position away from the object to be coated, the risk of the cleaning agent adhering to the object to be coated can be minimized.
(3) The residual pressure reducing mechanism Z1 is configured to include a residual pressure reducing valve 71 provided at a connection portion between the relief path 24 and the cleaning fluid supply path 21. Therefore, the residual pressure can be released in a timely manner by opening and closing the residual pressure reduction valve 71.
(4) In the above-mentioned residual pressure reduction mechanism Z1, since the cleaning agent supply valve 51, the air supply valve 61 and the residual pressure reduction valve 71 are installed on the common manifold block 81, these valves 51, 61 and 71 are used. The piping connecting to each other can be omitted. Therefore, the device can be configured compactly.
(5) In the present embodiment, since the cleaning agent in the relief path 24 is pressure-fed using the air from the air supply path 23, it is difficult for the cleaning agent to collect in the relief path 24. Therefore, it is possible to prevent an increase in the passage resistance of the cleaning agent and prevent the backflow of the accumulated cleaning agent. Therefore, the residual pressure can be reliably released for a long period of time.
(6) The rotary atomization type coating machine 1 of the present embodiment includes a control device for driving and controlling valves, and this control device performs residual pressure reduction control and in-path cleaning agent discharge control at a predetermined timing. It is configured as follows. Therefore, the residual pressure reduction control and the in-path cleaning agent discharge control can be reliably executed at appropriate timings.

[Second Embodiment]

Next, the rotary atomization type coating machine of the second embodiment will be described in detail with reference to FIG.

In the first embodiment, an example in which the residual pressure reduction mechanism Z1 is configured by using three valves 51, 61, and 71 is shown, but the present invention is of course not limited to this. Therefore, in the second embodiment, the residual pressure reduction mechanism Z2 is configured by using the two valves 91 and 101.

In the residual pressure reduction mechanism Z2, a cleaning agent supply valve 91 is provided at a connection portion between the cleaning agent supply path 22 and the cleaning fluid supply path 21. An air supply valve 101 is provided on the upstream side of the cleaning agent supply valve 91 in the cleaning fluid supply path 21, and the air supply path 23 and the relief path 24 are connected to the air supply valve 101. The cleaning agent supply valve 91 and the air supply valve 101 also function as residual pressure reduction valves.

The cleaning agent supply valve 91 of the present embodiment is a three-way valve driven by the pilot air PA1, and the air supply valve 101 is a three-way valve driven by the pilot air PA2. The cleaning agent supply valve 91 and the air supply valve 101 have the same structure in many parts as the cleaning agent supply valve 51 of the above embodiment. Therefore, here, the common parts will be assigned the same member number and detailed description thereof will be omitted, while different parts will be mainly described.

The cleaning agent supply valve 91 includes one pilot port 44C and three ports (first port 44A, second port 44B, third port 44D), and the valve body accommodating chamber 53 has ports 44A and 44B, respectively. It communicates with each of the 44Ds. The ring-shaped valve seat 59 is also provided on the upper side surface of the valve body accommodating chamber 53, and the upper end portion of the valve body 58 is brought into contact with and separated from the valve seat 59. Similarly, the air supply valve 101 includes one pilot port 45C and three ports (first port 45A, second port 45B, third port 45D), and the valve body accommodating chamber 53 has each port 45A, It communicates with 45B and 45D, respectively. The ring-shaped valve seat 59 is also provided on the upper side surface of the valve body accommodating chamber 53, and the upper end portion of the valve body 58 is brought into contact with and separated from the valve seat 59.

In the case of the cleaning agent supply valve 91, when the pilot air PA1 is not introduced into the pilot port 44C, the space between the first port 44A and the second port 44B is cut off and the valve is closed. On the other hand, the first port 44A and the third port 44D are in an open state in which they communicate with each other. On the other hand, when the pilot air PA1 is introduced, the first port 44A and the third port 44D are cut off from each other in a closed state. On the other hand, the first port 44A and the second port 44B are in an open state in which they communicate with each other. Further, in the case of the air supply valve 101, when the pilot air PA2 is not introduced into the pilot port 45C, the space between the first port 45A and the second port 45B is blocked and closed. On the other hand, the first port 45A and the third port 45D are in an open state in which they communicate with each other. On the other hand, when the pilot air PA2 is introduced, the first port 45A and the third port 45D are cut off from each other in a closed state. On the other hand, the first port 45A and the second port 45B are in an open state in which they communicate with each other.

The cleaning fluid supply path 21 is connected to the first port 44A of the cleaning agent supply valve 91, and the cleaning agent supply path 22 is connected to the second port 44B via the check valve CK1. Further, an air supply path 23 is connected to the second port 45B of the air supply valve 101 via a check valve CK1, and a relief path 24 is directly connected to the third port 45D.

Even when the residual pressure reduction mechanism Z2 of the second embodiment configured in this way is used, it is possible to perform the residual pressure reduction operation at the timings shown in the tables of FIGS. 4 and 5, for example. It becomes.

The embodiment of the present invention may be changed as follows.

-In the second embodiment, the air supply valve 101 uses a three-way valve driven by one type of pilot air PA2. For example, instead of this, a three-way valve driven by two types of pilot air is used. It is also possible to do. Specifically, in order to make the air supply valve 101 of FIG. 9 a normally open type three-way valve, two pilot ports are provided so that pilot air acts on both end faces of the piston 55. .. By using such a three-way valve, for example, it is possible to establish an open state in which the first port 45A, the second port 45B, and the third port 45D communicate with each other. Therefore, if the space between the first port 44A and the third port 44D of the cleaning agent supply valve 91 is closed in this open state, the cleaning agent supply valve 91 is maintained in the closed state and air is provided for a predetermined time. It is possible to supply air from the supply path 23 to the escape path 24. As a result, even when the residual pressure reducing mechanism configured as described above is used, it is possible to control the in-path cleaning agent discharge at the timings shown in the tables of FIGS. 6 to 8.

-In the first and second embodiments, the coating machine main body 11 is supported by the tip of the robot arm 2, but the present invention is not limited to this, and the coating machine main body 11 is supported by a support other than the robot arm 2. Good.

-In the first and second embodiments, a check valve 31 having a ball as the valve body 32, a valve seat 33, and a coil spring as the urging means 34 is used, but the present invention is not limited thereto. That is, as long as a passively operating type valve can be configured, a valve other than the ball may be used as the valve body 32, or a valve other than the coil spring may be used as the urging means 34.

In the first embodiment, the valves 51, 61, and 71 are installed on the common manifold block 81, but the present invention is not limited to this. For example, the valves 51, 61 are installed on the common manifold block 81 and the rest. The pressure reduction valve 71 may be installed at a different position. Further, of course, these three valves 51, 61, 71 may be connected to each other in a flow path by piping without using the manifold block 81. Further, of course, the valves 91 and 101 in the second embodiment may be installed and used on the common manifold block 81.

1 ... Rotary atomizing coating machine 2 ... Robot arm 3 ... Control device 11 ... Coating machine body 14 ... Rotary atomizing head 16 ... Central axis 17 ... Back surface (of rotating atomizing head) 21 ... Cleaning fluid supply path 22 ... Cleaning Agent supply path 23 ... Air supply path 24 ... Relief route 26 ... Cleaning nozzle 31 ... Check valve 32 ... Valve body 33 ... Valve seat 34 ... Energizing means 51 ... Cleaning agent supply valve 61 ... Air supply valve 71 ... Residual pressure reduction valve 81 ... Manifold block 91 ... Cleaning agent supply valve (having the function of a residual pressure reduction valve) 101 ... (Having the function of a residual pressure reduction valve) Air supply valve E1 ... Path end E2 ... Path start end Z1, Z2 ... Residual pressure reduction mechanism

Claims (9)

Cleaning is performed by ejecting a cleaning agent and air as a cleaning fluid toward the main body of the coating machine, the rotary atomizing head provided on the tip side and the central axis of the main body of the painting machine, and the back surface of the rotary atomizing head. Therefore, the cleaning nozzle arranged on the tip side of the main body of the coating machine and at a position eccentric from the central axis, and the cleaning agent supply path and the air supply path are connected to the start end of the path, and the cleaning nozzle located at the end of the path is connected to the cleaning nozzle. Separate from the cleaning nozzle on the upstream side of the cleaning fluid supply path in the middle of the cleaning fluid supply path so as to block the cleaning fluid supply path for supplying the cleaning agent and the air and the cleaning fluid supply path during non-cleaning. It is a rotary atomizing type coating machine equipped with a check valve arranged on the body .
The check valve has a valve body, a valve seat and an urging means, and the urging means is configured to urge the valve body toward the valve seat side against a normal flow of the cleaning fluid. The urging force of the urging means is preset so as to be smaller than the supply pressure of the cleaning fluid at the time of cleaning.
A rotary atomization type coating machine characterized in that a residual pressure reducing mechanism for reducing the residual pressure in the upstream region of the check valve in the cleaning fluid supply path is provided. The residual pressure reduction mechanism is connected to the upstream region of the check valve in the cleaning fluid supply path, and the cleaning fluid remaining in the upstream region of the check valve is released from the cleaning fluid supply path to allow the coating. The rotary atomization type coating machine according to claim 1, wherein the rotary atomization type coating machine is configured to include a relief path that is released at a position away from the machine body. The rotary atomization according to claim 2, wherein the residual pressure reduction mechanism further includes a residual pressure reduction valve provided at a connection portion between the relief path and the cleaning fluid supply path. Type painting machine. A cleaning agent supply valve is provided at a connection portion between the cleaning agent supply path and the cleaning fluid supply path.
An air supply valve is provided at the connection portion between the air supply path and the cleaning fluid supply path.
The rotary atomization type coating machine according to claim 3, wherein the cleaning agent supply valve, the air supply valve, and the residual pressure reduction valve are installed on a common manifold block. A cleaning agent supply valve is provided at a connection portion between the cleaning agent supply path and the cleaning fluid supply path.
An air supply valve is provided at a portion upstream of the cleaning agent supply valve in the cleaning fluid supply path, and the air supply path and the relief path are connected to the air supply valve.
The rotary atomization type coating machine according to claim 3, wherein the cleaning agent supply valve and the air supply valve also function as the residual pressure reducing valve. The rotary atomization type coating machine according to any one of claims 2 to 5, wherein the cleaning agent in the relief path is pumped using the air from the air supply path. It is equipped with a control device that drives and controls valves, as well as
According to claim 4 or 5, the control device performs residual pressure reduction control for opening the residual pressure reduction valve for a predetermined time during the period from immediately before the end of the cleaning period to the start of the coating period. The rotary atomization type coating machine described. It is equipped with a control device that drives and controls valves, as well as
The cleaning agent in the relief path is pumped using the air from the air supply path.
The control device is in the path for keeping the cleaning agent supply valve in the closed state, opening the air supply valve for a predetermined time, and opening the residual pressure reducing valve during the period excluding the painting period. The rotary atomization type coating machine according to claim 4 or 5 , wherein the cleaning agent discharge control is performed. The rotary atomization type coating machine according to any one of claims 1 to 8, wherein the coating machine main body is supported by the tip of a robot arm.

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