Coating temperature control device

Abstract

To provide a paint temperature control device that can stably adjust the paint temperature even in explosion-proof zones. [Solution] The paint temperature control device 50 comprises a paint head 32 that discharges paint onto an object to be painted, a supply pipe 33 provided in an explosion-proof zone that supplies paint to the paint head 32, a multi-layered pipe 51 interposed in the middle of the supply pipe 33 and consisting of an inner pipe 51a and an outer pipe 51b, the inner pipe 51a being connected to the supply pipe 33, and air or an inert fluid flowing through the outer pipe flow path 51c, which is the gap between the inner pipe 51a and the outer pipe 51b, and a control unit 100 that controls at least one of the temperature and flow rate of the air or inert fluid flowing through the outer pipe flow path 51c.

Description

Technical Field

[0001] The present invention relates to a paint temperature control device.

Background Art

[0002] In a coating apparatus having a coating head, the discharge performance of the paint from the coating head varies depending on the paint temperature. Therefore, it is required to stably maintain the paint temperature. However, since the paint temperature is almost the same as the ambient temperature in the coating booth, it is difficult to set the paint temperature higher or lower than the ambient temperature in the coating booth.

[0003] Patent Document 1 discloses that in a coating apparatus having a coating head, a heater for heating the paint is provided in a flow path constituting a paint circulation mechanism for sending the paint to the coating head, and it is assumed that an electric heater is used as the heater.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the inside of the coating booth is an explosion-proof zone, the use of an electric heater in that explosion-proof zone is not possible, and it is difficult to stably adjust the paint temperature.

[0006] Therefore, an object of the present invention is to provide a paint temperature control device capable of stably adjusting the paint temperature even in an explosion-proof zone.

Means for Solving the Problems

[0007] A paint temperature control device according to one aspect of the present invention comprises a paint head for dispensing paint onto an object to be painted, a supply pipe provided in an explosion-proof zone for supplying paint to the paint head, a multi-layered pipe interposed in the middle of the supply pipe and consisting of an inner pipe and an outer pipe, the inner pipe being connected to the supply pipe, and air or an inert fluid flowing through the outer pipe passage which is the gap between the inner pipe and the outer pipe, and a control unit for controlling at least one of the temperature and flow rate of the air or inert fluid flowing through the outer pipe passage. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a paint temperature control device that can stably adjust the paint temperature even in an explosion-proof zone. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing a painting robot for a vehicle painting machine equipped with a paint temperature control device according to this embodiment. [Figure 2] Figure 2 is a circuit diagram showing a paint circulation path with a paint temperature control device according to this embodiment. [Figure 3] Figure 3 is a circuit diagram showing the paint temperature control device according to this embodiment. [Figure 4] Figure 4 is a cross-sectional view showing the double tube in the circuit diagram of Figure 3 cut along the plane of the paper. [Figure 5] Figure 5 is a flowchart showing the control flow of the control unit of the paint temperature control device according to this embodiment. [Figure 6] Figure 6 shows the relationship between the paint temperature and the supply air temperature before and after the double-walled pipe in the supply line. [Modes for carrying out the invention]

[0010] The paint temperature control device 50 according to this embodiment will be described below with reference to the drawings.

[0011] Figure 1 is a schematic diagram showing the painting robot 11 of the vehicle painting machine 10 according to this embodiment. The painting robot 11 is positioned near the painting line in an automobile manufacturing plant and paints the vehicle body FR as it is transported along the painting line. In this embodiment, the object to be painted is an automobile vehicle body FR, but it may be something other than an automobile vehicle body FR.

[0012] [Painting robot] The painting robot 11 paints the vehicle body FR as it is transported from the upstream side of the painting line. The painting process may be carried out by painting the vehicle body FR while it is moving along the painting line, or by stopping the flow of the line at a predetermined position to perform the painting. The vehicle body FR that has been painted by the painting robot 11 is transported downstream of the painting line.

[0013] In this embodiment, a painting robot 11 is exemplified as a device for painting the vehicle body FR, but any device having a paint circulation path 30, as described later, may be used instead of a painting robot 11. Furthermore, while the painting robot 11 is exemplified as having a painting head unit 24 that can rotate around three axes, the X axis, the Y axis, and the Z axis, the painting head unit 24 may rotate around one of the X, Y, or Z axes, or around two axes.

[0014] Painting is performed with the purpose of forming a paint film on the surface of an object to be painted, thereby protecting the surface and providing an aesthetically pleasing appearance. The painting process may involve simply applying paint of a specific color or paint with a specific function, or it may involve applying multiple colors of paint or paints with specific functions in sequence.

[0015] The painting robot 11 is exemplified as an articulated robot, but a SCARA robot may also be used as long as it is capable of painting. As shown in Figure 1, the painting robot 11 comprises a base 20, legs 21, a rotary drive unit 22, a robot arm 23, and a painting head unit 24.

[0016] The base 20 is a fixing member that fixes the painting robot 11 to the floor surface of the painting line and supports the painting robot 11. The base 20 may be movable on the floor surface of the painting line.

[0017] The leg portion 21 has a lower part fixed to the base 20, an upper part connected to the rotation drive portion 22, and extends to a vertical height suitable for performing painting by the painting robot 11.

[0018] The rotation drive portion 22 is connected to the upper end of the leg portion 21 and has a rotation shaft portion 25 and a rotation arm 26. The rotation shaft portion 25 rotates the rotation arm 26 about a direction parallel to the floor surface (the X-axis direction shown in FIG. 1) by a motor (not shown). The rotation arm 26 rotates a robot arm 23 connected to the rotation arm 26 about a straight line orthogonal to the rotation center of the rotation shaft portion 25 (the Z-axis direction shown in FIG. 1).

[0019] The robot arm 23 has a first rotating arm 27 and a second rotating arm 28. One end of the first rotating arm 27 is connected to the rotation arm 26, and the other end is connected to the second rotating arm 28. The first rotating arm 27 rotates about the Z-axis direction shown in FIG. 1 by a motor (not shown) mounted on the rotation arm 26. One end of the second rotating arm 28 is connected to the first rotating arm 27, and the other end has a wrist portion 29 described later. The second rotating arm 28 rotates about the Z-axis direction shown in FIG. 1 by a motor (not shown).

[0020] The painting head unit 24 is disposed at the most distal end side of the painting robot 11 and injects paint onto the vehicle body FR of the automobile. A wrist portion 29 is held between the painting head unit 24 and the second rotating arm 28. The wrist portion 29 rotates the painting head unit 24 about at least one of the three axes (X-axis, Y-axis, and Z-axis) shown in FIG. 1.

[0021] The painting head unit 24 has a paint circulation path 30 inside for injecting paint from the painting head 32, and injects paint onto the vehicle body FR flowing on the painting line at an appropriate timing.

[0022] [Paint circulation path 30] Next, the paint circulation path 30 of the vehicle painting machine 10 will be described with reference to Figure 2. Figure 2 is a circuit diagram showing the paint circulation path 30 of the vehicle painting machine 10 equipped with a paint temperature control device 50 according to this embodiment.

[0023] The paint circulation path 30 includes a paint tank 31, a paint head 32, a supply path 33, a return path 34, a bypass path 44, and a paint temperature control device 50. The paint circulation path 30 is located in an explosion-proof zone, which is an area where flammable gases are generated, either entirely or in part.

[0024] The paint circulation path 30 is a circulation circuit that, when painting the vehicle body FR, supplies paint stored in the paint tank 31 to the paint head 32 via the supply path 33, and returns any paint not used by the paint head 32 to the paint tank 31 via the return path 34. The paint circulation path 30 also functions as a circulation circuit that returns paint stored in the paint tank 31 from the supply path 33, via the bypass path 44, to the paint tank 31 via the return path 34 when the vehicle body FR is not being painted.

[0025] Here, in the supply channel 33, the direction of paint supply is referred to as the upstream side towards the paint tank 31 and the downstream side towards the paint head 32. Similarly, in the return channel 34, the side towards the paint head 32 is referred to as the upstream side and the side towards the paint tank 31 is referred to as the downstream side.

[0026] The paint tank 31 stores the paint used when painting the vehicle body FR with the painting head 32. The paint tank 31 is located outside the painting robot 11 (for example, on the floor of the painting room) or on the robot arm 23. Paint is replenished from the outside as needed during the process of painting the vehicle body FR with the painting head 32.

[0027] The paint head 32 is an inkjet type head that has a nozzle forming surface 32b on which a plurality of nozzles 32a are arranged, and ejects paint supplied via a supply passage 33 from each of the plurality of nozzles 32a to form a paint film on the surface of the vehicle body FR. A predetermined number of nozzles 32a constitute a nozzle row (not shown), and this nozzle row is arranged diagonally with respect to the scanning direction, which is the direction in which the paint head 32 moves, but the nozzle row may also be arranged along or perpendicular to the scanning direction. The detailed configuration of the paint head 32 is omitted.

[0028] The supply channel 33 is a flow path that supplies paint stored in the paint tank 31 to the paint head 32. The supply channel 33 includes, in order from upstream, a flow meter 35, a first gear pump 36, a first pressure sensor (PS1) 37, a paint temperature control device 50, a first three-way valve 38, and a second pressure sensor (PS2) 39. The flow meter 35 measures the flow rate of paint flowing through the supply channel 33. The first gear pump 36 pumps paint from the paint tank 31 along the supply channel 33 to the paint head 32. The first pressure sensor (PS1) 37 measures the pressure of the paint downstream of the first gear pump 36 in the supply channel 33. The paint temperature control device 50 adjusts the temperature of the paint flowing through the supply channel 33. The paint temperature control device 50 will be described later.

[0029] The first three-way valve 38 maintains a state in which the supply passage 33 and the first head passage 33a provided by the painting head 32 are in communication when the vehicle body FR is being painted by the painting head 32. When the vehicle body FR is not being painted by the painting head 32, the first three-way valve 38 switches to a state in which the supply passage 33 and the bypass passage 44 are in communication. The second pressure sensor (PS2) 39 measures the pressure of the paint in the first head passage 33a downstream of the first three-way valve 38.

[0030] The bypass channel 44 connects the first three-way valve 38 and the second three-way valve 41 (described later), and when painting is not performed by the painting head 32, the paint supplied from the supply channel 33 is recirculated to the return channel 34, bypassing the painting head 32.

[0031] The return channel 34 is a channel that directs paint that was not used by the painting head 32 downstream of the supply channel 33 to the paint tank 31. The return channel 34 includes, in order from upstream, a third pressure sensor (PS3) 40, a second three-way valve 41, a fourth pressure sensor (PS4) 42, and a second gear pump 43.

[0032] The third pressure sensor (PS3) 40 measures the pressure of the paint in the second head passage 34a upstream of the second three-way valve 41. The second three-way valve 41 is connected to the downstream end of the second head passage 34a. The second three-way valve 41 maintains a state in which the second head passage 34a and the return passage 34 are in communication when the vehicle body FR is being painted by the painting head 32. The second three-way valve 41 switches to a state in which the bypass passage 44 and the return passage 34 are in communication when the vehicle body FR is not being painted by the painting head 32.

[0033] The fourth pressure sensor (PS4) 42 measures the pressure of the paint upstream of the second gear pump 43 in the return passage 34. The second gear pump 43 sucks and pumps the paint along the return passage 34 toward the paint tank 31.

[0034] The paint circulation path 30 is configured as described above. Paint stored in the paint tank 31 is pumped along the supply path 33 by the first gear pump 36, and any paint remaining after painting at the paint head 32, or paint that has passed through the bypass path 44, is pumped back to the paint tank 31 along the return path 34 by the second gear pump 43.

[0035] [Paint temperature control device 50] The paint temperature control device 50 will be described with reference to Figures 3 and 4. Figure 3 is a circuit diagram showing the paint temperature control device 50, and Figure 4 is a cross-sectional view showing the double pipe 51 in the circuit diagram of Figure 3 cut along the plane of the paper. As described above, since the paint circulation path 30 is installed in the explosion-proof zone, the paint temperature control device 50 is also placed in the explosion-proof zone.

[0036] Furthermore, the viscosity of paint changes with temperature; the higher the temperature, the lower the viscosity, and the lower the temperature, the higher the viscosity. This depends on the change in shear stress of the paint with temperature, and from the viewpoint of preventing clogging in the nozzle 32a of the painting head 32, it is preferable to maintain the temperature at a predetermined level or higher, but not too high. In addition, in order to maintain the desired painting quality, it is necessary to keep the paint temperature stable and constant. Therefore, in this embodiment, a paint temperature control device 50 is provided to stably maintain the paint temperature, as will be explained below.

[0037] The paint temperature control device 50 comprises a double pipe 51, an air supply pipe 52, an air return pipe 53, and a control unit 100.

[0038] As shown in Figure 4, the double-walled pipe 51 is a double-walled pipe composed of an inner pipe 51a with a circular cross-section and an outer pipe 51b with a circular cross-section that houses the inner pipe 51a. The double-walled pipe 51 is composed of an inner pipe 51a connected to the supply passage 33 at both ends, and an outer pipe 51b that extends parallel to the inner pipe 51a, with the inner pipe 51a housed in the center of the inside and a cylindrical space, the outer pipe flow path 51c, secured between the inner pipe 51a and the outer pipe 51b. The outer pipe 51b is connected to joints 54 at the left and right ends of the paper, and the outer pipe flow path 51c inside the outer pipe 51b and the space 54a inside the joints 54 are in communication. That is, in Figure 4, the lower end of the joint 54 at the left end of the paper and the lower end of the joint 54 at the right end of the paper are in communication via the outer pipe 51b.

[0039] The inner tube 51a is supported by joints 54 on the left and right sides of the paper, and normally the outer surface of the inner tube 51a and the inner surface of the outer tube 51b do not come into contact. However, since the inner tube 51a is made of fluororesin and the outer tube 51b is made of nylon, when the inner tube 51a and the outer tube 51b are bent between the joints 54, they will curve according to their respective bending properties. Even if the outer surface of the inner tube 51a and the inner surface of the outer tube 51b come into contact, there is no problem as long as there is enough space between the outer surface of the inner tube 51a and the inner surface of the outer tube 51b for air to flow.

[0040] Returning to Figures 2 and 3, the double pipe 51 is connected between the first pressure sensor (PS1) 37 and the first three-way valve 38 of the supply passage 33, such that the inner pipe 51a of the double pipe 51 is interposed in the middle of the supply passage 33. That is, paint that has passed through the first pressure sensor (PS1) 37 flows into the inner pipe 51a of the double pipe 51, and the paint that flows out of the inner pipe 51a flows toward the first three-way valve 38.

[0041] The air supply pipe 52 is a pipe that supplies air to the outer pipe flow path 51c of the double pipe 51 by a pump (not shown). The air return pipe 53 is a pipe that discharges air from the outer pipe flow path 51c. The upstream side of the outer pipe flow path 51c is connected to the air supply pipe 52 and the downstream side is connected to the air return pipe 53. This allows air to flow through the outer pipe flow path 51c while paint flows through the inner pipe 51a in the double pipe 51. At this time, the paint temperature can be increased by heat exchange between the low-temperature paint and the heated, high-temperature air.

[0042] Furthermore, the air supply pipe 52 includes, in order from upstream, a regulator 55, an air heater 56, an air flow meter 57, and an air temperature sensor 58. The regulator 55 adjusts the pressure and flow rate of compressed air flowing through the air supply pipe 52 based on a command from the control unit 100. The air heater 56 heats the air using the compressed air supplied from the regulator 55 based on a command from the control unit 100. The air heater 56 used here is a device that supplies compressed and heated air without using electricity or fire, but other devices may also be used. In addition, when the air heater 56 is operating, it may have a function to lower the temperature of the paint by supplying only the cold air that is discharged to the outside separately from the hot air to the air supply pipe 52, i.e., by using it as an air cooler. The air flow meter 57 measures the flow rate of air flowing through the air supply pipe 52. The air temperature sensor 58 measures the temperature of the air flowing through the air supply pipe 52.

[0043] Furthermore, the supply line 33 is equipped with a first temperature sensor 59 and a second temperature sensor 60. The first temperature sensor 59 measures the temperature of the paint flowing upstream of the double pipe 51. The second temperature sensor 60 measures the temperature of the paint flowing downstream of the double pipe 51.

[0044] The control unit 100 controls the temperature and flow rate of the air supplied to the double pipe 51 using a regulator 55 and an air heater 56, based on the measured values ​​of the first temperature sensor 59, the second temperature sensor 60, the air temperature sensor 58, and the air flow meter 57. This controls the temperature or amount of air supplied to the outer pipe flow path 51c of the double pipe 51.

[0045] [control] The control flow of the control unit 100 of the paint temperature control device 50 will be explained with reference to the flowchart in Figure 5. The following control is performed when it is desired to heat the paint.

[0046] In step S1, the control unit 100 determines whether the paint temperature is lower than the target temperature. If the paint temperature is lower than the target temperature, the process proceeds to step S2; if it is at or above the target temperature, the process proceeds to step S5.

[0047] In step S2, the control unit 100 increases the output of the regulator 55 and the air heater 56. When the output is increased, the regulator 55 generates higher compressed air, and the air heater 56 generates air at a higher temperature by increasing the pressure of the compressed air.

[0048] In step S3, the control unit 100 determines whether the temperature of the air flowing through the air supply pipe 52 is above the set temperature. If the air temperature is above the set temperature, the process proceeds to step S4; if it is below the set temperature, the process returns to step S2. The set temperature is a value used to calculate the output of the air heater 56 necessary to efficiently heat the paint based on the temperature difference of the paint between the inlet and outlet of the double pipe 51, and is determined in advance through experiments or other means. For example, the set temperature is set so as not to cause the paint temperature to overshoot the target temperature by increasing the output of the air heater 56 too much when the temperature difference of the paint between the inlet and outlet of the double pipe 51 is small.

[0049] In step S4, the control unit 100 determines whether the air flow rate through the air supply pipe 52 is equal to or greater than the set flow rate. If the air flow rate is equal to or greater than the set flow rate, the process returns to step S1; if it is less than the set flow rate, the process returns to step S2. The set flow rate is a value used to calculate the output of the regulator 55 necessary to efficiently heat the paint based on the temperature difference of the paint between the inlet and outlet of the double pipe 51, and is determined in advance by experimentation or other means. For example, the set flow rate is defined so as to prevent the paint temperature from overshooting the target temperature by increasing the output of the regulator 55 too much when the temperature difference of the paint between the inlet and outlet of the double pipe 51 is small.

[0050] In step S5, the control unit 100 stabilizes the outputs of the regulator 55 and the air heater 56 to a steady output. Once the output is stabilized, the temperature of the paint in the supply path 33 is stably maintained by the supply of air heated by the regulator 55 and the air heater 56.

[0051] [Temperature changes in paint] The relationship between the paint temperature and the supply air temperature before and after the double pipe 51 in the supply path 33 will be explained with reference to Figure 6.

[0052] In Figure 6, the horizontal axis represents time, and the vertical axis represents temperature. The left axis of the vertical line represents the paint temperature, and the right axis represents the air temperature. Furthermore, the paint inlet temperature is the value measured by the first temperature sensor 59, and the paint outlet temperature is the value measured by the second temperature sensor 60.

[0053] As shown in the figure, when the paint temperature at the inlet of the double-walled pipe 51 is approximately 25°C, air at approximately 26.5°C before heating is supplied from the air supply pipe 52. From this state, when the air heater 56 and regulator 55 are activated to heat the air supplied from the air supply pipe 52, the temperature difference between the paint temperature at the inlet and the paint temperature at the outlet of the double-walled pipe 51 increases as the temperature of the heated air rises. In other words, the paint temperature at the outlet of the double-walled pipe 51 rises in accordance with the temperature of the air flowing through the outer tube flow path 51c of the double-walled pipe 51.

[0054] In this way, by pre-mapping the target temperature of the paint at the outlet after it has passed through the inner tube 51a of the double tube 51 with the temperature and flow rate of the heated air to be flowed through the outer tube flow path 51c of the double tube 51, the paint temperature can be stably maintained at the desired temperature.

[0055] [Differentiation] In the above embodiment, an example of a vehicle painting machine 10 having an inkjet type painting head 32 was provided, but similar effects can be obtained even if a painting head of a type other than inkjet type is used for the painting head 32.

[0056] Furthermore, although air is flowed through the air supply pipe 52 in the above embodiment, an inert fluid that is safe in the explosion-proof zone may be used instead of air.

[0057] Furthermore, in the above embodiment, the outer pipe flow path 51c is connected to the air supply pipe 52 on its upstream side and to the air return pipe 53 on its downstream side. However, the outer pipe flow path 51c may be arranged so that its downstream side is connected to the air supply pipe 52 and its upstream side is connected to the air return pipe 53.

[0058] Furthermore, although the above embodiment illustrates the case where the paint temperature control device 50 raises the paint temperature, it can also be applied when lowering the paint temperature. In this case, air at a temperature lower than the paint temperature should be supplied from the air supply pipe 52.

[0059] Furthermore, in the above embodiment, only one inner pipe 51a is provided inside the outer pipe 51b, but multiple inner pipes 51a may be provided in parallel. In this case, simply by connecting all the inner pipes 51a to the supply passage 33, the overall surface area of ​​the inner pipes 51a increases, thereby increasing the heat exchange efficiency.

[0060] Furthermore, in the above embodiment, the inner tube 51a is provided substantially parallel to the outer tube 51b, but the inner tube 51a may be made into a continuous curved shape such as a helical shape inside the outer tube 51b. In this case, the overall surface area of ​​the inner tube 51a increases, so the heat exchange efficiency can be increased.

[0061] Furthermore, in the above embodiment, the inner tube 51a is made of fluororesin and the outer tube 51b is made of nylon as an example, but both the inner tube 51a and the outer tube 51b may be made of other resins. Also, in the structure of a paint head where the bendability of the supply passage 33 does not need to be considered, the inner tube 51a and the outer tube 51b may be made of metal in order to improve the heat exchange efficiency.

[0062] Furthermore, although the above embodiment illustrates a structure in which the outer tube 51b houses the inner tube 51a at its internal center, the inner tube 51a may be provided radially eccentrically from the center inside the outer tube 51b.

[0063] Furthermore, although the above embodiment illustrates the case in which an air heater 56 that supplies compressed and heated air is used without using electricity or fire, an electric heater or the like may be installed outside the explosion-proof zone to heat the air, and the heated air may be flowed to the supply passage 33 via the air supply pipe 52.

[0064] Furthermore, in the above embodiment, the paint temperature control device 50 is installed between the first pressure sensor (PS1) 37 and the first three-way valve 38 of the supply passage 33, but it may be installed in any other location as long as it is in a position where the paint can be heated.

[0065] Furthermore, in the above embodiment, heat exchange between paint and air is performed by a double-walled pipe 51 consisting of an inner pipe 51a and an outer pipe 51b. However, a multi-layered pipe with a multi-layered structure in which the inner pipe 51a and outer pipe 51b are arranged in three or more layers in the radial direction may also be used. In this case, the inner and outer pipes of the multi-layered pipe are arranged alternately in the radial direction, and the passages in contact with the inner surface of the inner pipes are connected to the supply passage 33. This increases the contact area between the inner and outer pipes, thereby further improving the heat exchange efficiency.

[0066] Furthermore, in the above embodiment, the inner tube 51a and outer tube 51b are exemplified as having a circular cross-section, but they may have shapes other than circular.

[0067] [Supplementary explanation of the embodiment] The embodiments described above are all preferred examples of the present invention. The numerical values, components, arrangement positions of components, and connection configurations shown in the embodiments above are examples only and are not intended to limit the present invention. Furthermore, the figures are not necessarily strictly illustrative.

[0068] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0069] The series of processes described above can be executed by hardware or by software. When the series of processes are executed by software, the programs that make up the software are installed from a program storage medium on a computer that is built into dedicated hardware, or on a general-purpose computer that can perform various functions by installing various programs.

[0070] The programs executed by the computer may be programs that are processed chronologically in the order described herein, or they may be programs that are processed in parallel or at necessary times, such as when a call is made.

[0071] [Note] The contents described in some of the embodiments above can be understood, for example, as follows:

[0072] (1) Multiple tubes The system includes a paint head 32 that discharges paint onto an object to be painted, a supply passage 33 located in an explosion-proof zone that supplies paint to the paint head 32, a double pipe 51 interposed in the middle of the supply passage 33 and having a double structure consisting of an inner pipe 51a and an outer pipe 51b, with the inner pipe 51a connected to the supply passage 33 and air flowing through the outer pipe passage 51c, which is the gap between the inner pipe 51a and the outer pipe 51b, and a control unit 100 that controls at least one of the temperature and flow rate of the air flowing through the outer pipe passage 51c.

[0073] As a result, the paint heading towards the paint head 32 undergoes temperature control through heat exchange with air in the supply path 33, allowing the paint temperature to be controlled even in explosion-proof zones, thus maintaining stable paint discharge performance. Furthermore, since air is used for heat exchange, expensive control equipment for explosion-proof environments is not required, thus reducing costs. In addition, by controlling the paint temperature, it is possible to maintain the appropriate viscosity of the paint, improving the paint quality when painting objects such as vehicles.

[0074] Air or an inert fluid may flow through the outer tube passage 51c of the double-walled pipe 51.

[0075] As a result, in addition to having high explosion-proof performance, the weight of the fluid flowing through the outer pipe passage 51c is reduced, which reduces the weight of the double pipe 51 during painting and improves the flexibility of its placement in the supply passage 33. Also, because air is lightweight, the pump load when flowing it through the outer pipe passage 51c is reduced, allowing the use of a smaller pump. Furthermore, if air is partially introduced into the air supply pipe 52 from the device that supplies air to the paint circulation path 30 for cleaning, air can be supplied to the air supply pipe 52 without installing a new pump. Thus, the overall weight of the paint temperature control device 50 can be reduced.

[0076] (2) Heating or cooling The control unit 100 may control the air temperature to be different from the paint temperature in the supply passage 33.

[0077] This allows for improved discharge performance from the paint head 32 by raising the paint temperature and lowering its viscosity. Furthermore, since air is used to raise the paint temperature, the paint can be safely heated even in explosion-proof zones.

[0078] Furthermore, the paint temperature can be lowered by setting the air temperature lower than the paint temperature in the supply passage 33. When the temperature inside the paint booth is high, the paint temperature will be almost the same as the ambient temperature, causing the paint temperature to rise. In such cases, the paint can be cooled to maintain the desired viscosity.

[0079] (3)Outer tube material The outer tube 51b may be made of resin.

[0080] This ensures the thermal insulation of the outer pipe 51b, and even in areas where the supply passage 33 is bent or where bending loads are applied during painting, the flexibility of the outer pipe 51b allows it to adapt to changes in shape, thus improving the degree of freedom in the placement of the double pipe 51.

[0081] (4) Multiple internal pipes Multiple inner pipes 51a may be provided inside the outer pipe 51b, and each of the multiple inner pipes 51a may be connected to the supply line 33.

[0082] This increases the overall surface area of ​​the inner tubes 51a, thereby improving the heat exchange efficiency between the paint flowing through each inner tube 51a and the air flowing through the outer tube channel 51c, and allowing for more efficient control of the paint temperature.

[0083] (5 joints) At least one end of the inner pipe 51a may be connected to the supply line 33 via a joint 54 supported by the outer pipe 51b.

[0084] As a result, the inner pipe 51a can be supported by the outer pipe 51b via the joint 54, thereby suppressing radial displacement of the inner pipe 51a within the outer pipe 51b and preventing a portion of the outer pipe flow path 51c from being blocked by deformation of the inner pipe 51a. Therefore, a decrease in heat exchange efficiency between the paint flowing through the inner pipe 51a and the air flowing through the outer pipe flow path 51c can be prevented, and the paint temperature can be controlled more efficiently. [Explanation of Symbols]

[0085] 10 Vehicle painting machines 32 Painting Heads 33 Supply path (supply pipe) 50 Paint temperature control device 51 Double pipe 51a Inner tube 51c Outer tube flow path 54 Fittings 100 Control Unit

Claims

1. A paint head that dispenses paint onto the object to be painted, A supply pipe provided in the explosion-proof zone to supply the paint to the painting head, Interposed in the middle of the supply pipe is a multi-layered structure consisting of an inner pipe and an outer pipe, wherein the inner pipe is connected to the supply pipe, and air or an inert fluid flows through the outer pipe passage, which is the gap between the inner pipe and the outer pipe. A control unit that controls the temperature and flow rate of at least one of the air or inert fluid flowing through the outer tube passage, A paint temperature control device characterized by comprising the following features.

2. A paint temperature control device according to claim 1, The control unit controls the temperature of the air or the inert fluid so that it is different from the temperature of the paint in the supply pipe. A paint temperature control device characterized by the following features.

3. A paint temperature control device according to claim 1, The outer tube is formed from resin. A paint temperature control device characterized by the following features.

4. A paint temperature control device according to claim 1, Multiple inner tubes are provided within the outer tube, and each of the multiple inner tubes is connected to the supply pipe. A paint temperature control device characterized by the following features.

5. A paint temperature control device according to claim 1, At least one end of the inner pipe is connected to the supply pipe via a joint supported by the outer pipe. A paint temperature control device characterized by the following features.

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