Coating temperature control device

Abstract

To provide a paint temperature adjusting device capable of stably adjusting paint temperature even in an explosion-proof zone. [Solution] The paint temperature adjustment device 50 comprises a paint head 32 that ejects paint onto an object to be painted, a supply pipe 33 located in an explosion-proof zone that supplies paint toward the paint head 32, a multiple-layer structure consisting of an inner pipe 51a and an outer pipe 51b interposed in the middle of the supply pipe 33, in which the inner pipe 51a is connected to the supply pipe 33, and air or an inert fluid flows through an 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 technology]

[0002] In a coating device with a coating head, the paint discharge performance from the coating head changes depending on the paint temperature, so it is necessary to maintain a stable paint temperature. However, since the paint temperature is almost the same as the environmental temperature inside the coating booth, it is difficult to set the paint temperature higher or lower than the environmental temperature inside the coating booth.

[0003] Patent document 1 discloses that in a painting device having a painting head, a heater for heating paint is provided in a flow path that constitutes a paint circulation mechanism that sends paint to the painting head, and it is assumed that an electric heater is used as the heater. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-055933 Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the inside of the paint booth is an explosion-proof zone, electric heaters cannot be used within the explosion-proof zone, making it difficult to stably adjust the paint temperature.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a paint temperature adjusting device that can stably adjust the paint temperature even in an explosion-proof zone. [Means for solving the problem]

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

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

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a coating robot of a vehicle coating machine having a paint temperature adjusting device according to this embodiment. [Figure 2] FIG. 2 is a circuit diagram showing a paint circulation path having a paint temperature adjusting device according to this embodiment. [Figure 3] FIG. 3 is a circuit diagram showing the paint temperature adjusting device according to this embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing the double pipe in the circuit diagram of FIG. 3 cut along the paper surface. [Figure 5] FIG. 5 is a flowchart showing the control flow of the control unit of the paint temperature adjusting device according to this embodiment. [Figure 6] FIG. 6 is a diagram showing the relationship between the paint temperature and the supply air temperature before and after the double pipe in the supply passage. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the paint temperature adjusting device 50 according to this embodiment will be described with reference to the drawings.

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

[0012] [Painting robot] The painting robot 11 paints the vehicle body FR that is transported from the upstream side of the painting line. In the painting process, the vehicle body FR may be painted while moving along the painting line, or the flow of the line may be stopped at a predetermined position and painting may be performed. The vehicle body FR that has been painted by the painting robot 11 is transported toward the downstream side 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 described below is not limited to the painting robot 11. Furthermore, the painting robot 11 is exemplified as a robot in which the painting head unit 24 can rotate around three axes, the X-axis, the Y-axis, and the Z-axis, but the painting head unit 24 may rotate around one of the X-axis, the Y-axis, or the Z-axis, or may rotate around two axes.

[0014] Painting is carried out for the purpose of forming a paint film on the surface of an object to be painted, for the purpose of protecting the surface and providing a beautiful appearance. The painting process may involve simply painting with a paint of a specific color or with a specific function, or it may involve sequentially applying paints of multiple colors or with specific functions.

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

[0016] The base 20 is a fixed 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 21 has a lower portion fixed to the base 20 and an upper portion connected to the rotation drive unit 22, and is extended to a vertical height suitable for painting by the painting robot 11.

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

[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 rotating arm 26, and the other end is connected to the second rotating arm 28. The first rotating arm 27 is rotated around the Z-axis direction shown in FIG. 1 by a motor (not shown) mounted on the rotating arm 26. The second rotating arm 28 has one end connected to the first rotating arm 27, and has a wrist unit 29 (described later) at the other end. The second rotating arm 28 is rotated around the Z-axis direction shown in FIG. 1 by a motor (not shown).

[0020] The painting head unit 24 is located at the very tip of the painting robot 11 and sprays paint onto the automobile body FR. A wrist unit 29 is held between the painting head unit 24 and the second rotating arm 28. The wrist unit 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 paint head unit 24 has a paint circulation path 30 therein for spraying paint from a paint head 32, and sprays paint at appropriate timing onto the vehicle body FR moving along the painting line.

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

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

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

[0025] In the supply path 33, the paint tank 31 side is referred to as the upstream side, and the paint head 32 side is referred to as the downstream side. In the return path 34, the paint head 32 side is referred to as the upstream side, and the paint tank 31 side is referred to as the downstream side.

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

[0027] The paint head 32 is an inkjet head having a nozzle forming surface 32b on which a plurality of nozzles 32a are arranged, and paint supplied via a supply path 33 is ejected 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 form a nozzle row (not shown), and the 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 the scanning direction or perpendicular to it. Note that a detailed description of the configuration of the paint head 32 will be omitted.

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

[0029] When the paint head 32 is painting the vehicle body FR, the first three-way valve 38 maintains a state in which the supply path 33 communicates with the first head flow path 33a of the paint head 32. When the paint head 32 is not painting the vehicle body FR, the first three-way valve 38 switches to a state in which the supply path 33 communicates with the bypass flow path 44. The second pressure sensor (PS2) 39 measures the pressure of the paint in the first head flow path 33a downstream of the first three-way valve 38.

[0030] The bypass flow path 44 connects the first three-way valve 38 to the second three-way valve 41 described later, and when painting is not being performed by the painting head 32, the paint supplied from the supply path 33 bypasses the painting head 32 and returns to the return flow path 34.

[0031] The return flow path 34 is a flow path that allows paint not used by the paint head 32 to flow toward the downstream side of the return flow path 34, which is the upstream side of the supply path 33, and return it to the paint tank 31. The return flow path 34 has, in order from the upstream side, 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 flow path 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 flow path 34a. The second three-way valve 41 maintains a state in which the second head flow path 34a and the return flow path 34 are in communication with each other when the paint head 32 is painting the vehicle body FR. Furthermore, the second three-way valve 41 switches to a state in which the bypass flow path 44 and the return flow path 34 are in communication with each other when the paint head 32 is not painting the vehicle body FR.

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

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

[0035] [Paint temperature control device 50] The paint temperature adjustment device 50 will be described with reference to Figures 3 and 4. Figure 3 is a circuit diagram showing the paint temperature adjustment 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 provided in the explosion-proof zone, the paint temperature adjustment device 50 is also placed in the explosion-proof zone.

[0036] The viscosity of paint changes with temperature, with higher temperatures resulting in lower viscosity and lower temperatures resulting in higher viscosity. This is due to the change in shear stress of the paint with temperature, and from the perspective of preventing clogging in the nozzle 32a of the paint head 32, it is preferable to maintain the paint at a temperature above a predetermined level but not too high. Furthermore, to maintain the desired painting quality, it is necessary to maintain a stable, constant paint temperature. Therefore, in this embodiment, a paint temperature adjustment device 50 is provided to maintain a stable paint temperature, as described below.

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

[0038] As shown in Fig. 4, the double pipe 51 is a pipe with a double structure 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 pipe 51 is composed of an inner pipe 51a connected to the supply path 33 at both ends and an outer pipe 51b that houses the inner pipe 51a in the center and extends parallel to the inner pipe 51a, with an outer pipe flow path 51c, which is a cylindrical space, between the inner pipe 51a and the inner pipe 51a. The outer pipe 51b is connected to fittings 54 at the left and right ends of the drawing, and the outer pipe flow path 51c in the outer pipe 51b is connected to a space 54a in the fitting 54. In other words, in Fig. 4, the lower end of the fitting 54 at the left end of the drawing and the lower end of the fitting 54 at the right end of the drawing are connected via the outer pipe 51b.

[0039] The inner pipe 51a is supported by joints 54 on the left and right sides of the drawing, and normally the outer surface of the inner pipe 51a does not come into contact with the inner surface of the outer pipe 51b. However, because the inner pipe 51a is made of fluororesin and the outer pipe 51b is made of nylon, when the inner pipe 51a and the outer pipe 51b are bent between the joints 54, they bend according to their respective bendability. Note that even if the outer surface of the inner pipe 51a comes into contact with the inner surface of the outer pipe 51b, there is no problem as long as there is a gap between the outer surface of the inner pipe 51a and the inner surface of the outer pipe 51b that is large enough to allow air to flow between them.

[0040] 2 and 3, the double pipe 51 is connected between the first pressure sensor (PS1) 37 of the supply path 33 and the first three-way valve 38, with the inner pipe 51a of the double pipe 51 interposed in the middle of the supply path 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 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 using a pump (not shown). The air return pipe 53 is a pipe that discharges air from the outer pipe flow path 51c. The outer pipe flow path 51c is connected to the air supply pipe 52 on the upstream side and to the air return pipe 53 on the downstream side. This makes it possible to flow air into the outer pipe flow path 51c while flowing paint into the inner pipe 51a in the double pipe 51. At this time, heat exchange occurs between the low-temperature paint and the heated, high-temperature air, thereby raising the temperature of the paint.

[0042] Furthermore, the air supply pipe 52 includes, from upstream to downstream, 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 the compressed air flowing through the air supply pipe 52 based on commands from the control unit 100. The air heater 56 uses the compressed air supplied from the regulator 55 to heat the air based on commands from the control unit 100. Note that the air heater 56 used here is a device that supplies heated air through compression without using electricity or fire, but other devices may also be used. Furthermore, when the air heater 56 is operating, it may supply only the cold air discharged to the outside separately from the hot air to the air supply pipe 52, i.e., function as an air cooler to lower the temperature of the paint. The air flow meter 57 measures the flow rate of the 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, a first temperature sensor 59 and a second temperature sensor 60 are provided in the supply path 33. 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 sent to the double pipe 51 using the regulator 55 and the 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 adjusting device 50 will be described with reference to the flowchart of Fig. 5. The following control is performed in a situation where 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, and if the paint temperature is equal to or higher than the target temperature, the process proceeds to step S5.

[0047] In step S2, the control unit 100 increases the outputs of the regulator 55 and the air heater 56. When the outputs are increased, the regulator 55 generates more highly 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 equal to or higher than the set temperature. If the air temperature is equal to or higher than the set temperature, the process proceeds to step S4; if the air temperature is lower than the set temperature, the process returns to step S2. The set temperature is a setting value used to calculate the output of the air heater 56 required to efficiently heat the paint based on the temperature difference between the paint's inlet and outlet of the double pipe 51, and is determined in advance by experiment or the like. For example, the set temperature is specified so as to prevent the paint's temperature from overshooting the target temperature by increasing the output of the air heater 56 too much when the temperature difference between the paint's inlet and outlet of the double pipe 51 is small.

[0049] In step S4, the control unit 100 determines whether the flow rate of air flowing 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 set value used to calculate the output of the regulator 55 required to efficiently heat the paint based on the temperature difference between the paint's inlet and outlet of the double pipe 51, and is determined in advance by experiment or the like. For example, the set flow rate is specified so as to prevent the paint's temperature from overshooting the target temperature by increasing the output of the regulator 55 too much when the temperature difference between the paint's 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 at steady outputs. When the outputs are stabilized, the temperature of the paint in the supply path 33 is maintained stable by the supply of air heated by the regulator 55 and the air heater 56.

[0051] [Temperature change of paint] The relationship between the paint temperature and the supply air temperature before and after the double pipe 51 in the supply passage 33 will be described with reference to FIG.

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

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

[0054] In this way, by mapping in advance the target temperature of the paint at the exit after passing through the inner tube 51a of the double tube 51 and the temperature and flow rate of the heated air to be flowed into the outer tube flow path 51c of the double tube 51, the paint temperature can be maintained stably at the desired temperature.

[0055] [Variations] In the above embodiment, the vehicle sprayer 10 having the inkjet type paint head 32 is exemplified, but the same effect can be obtained even if the paint head 32 is a paint head of a type other than the inkjet type.

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

[0057] Furthermore, in the above embodiment, the outer pipe flow path 51c is connected at its upstream side to the air supply pipe 52 and at its downstream side to the air return pipe 53, but the outer pipe flow path 51c may also 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] In the above embodiment, the paint temperature adjusting device 50 is used to increase the temperature of the paint, but it can also be used to decrease the temperature of the paint. In this case, air at a temperature lower than the temperature of the paint is supplied from the air supply pipe 52.

[0059] In addition, 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 connecting all the inner pipes 51a to the supply path 33 increases the overall surface area of ​​the inner pipes 51a, thereby improving the heat exchange efficiency.

[0060] In the above embodiment, the inner pipe 51a is disposed substantially parallel to the outer pipe 51b, but the inner pipe 51a may have a continuously curved shape such as a spiral shape inside the outer pipe 51b. In this case, the overall surface area of ​​the inner pipe 51a increases, thereby improving the heat exchange efficiency.

[0061] In the above embodiment, the inner tube 51a is made of fluororesin and the outer tube 51b is made of nylon, but both the inner tube 51a and the outer tube 51b may be made of other resins. In a coating head structure in which the bendability of the supply passage 33 does not need to be taken into consideration, the inner tube 51a and the outer tube 51b may be made of metal to increase heat exchange efficiency.

[0062] Furthermore, in the above embodiment, the outer tube 51b accommodates the inner tube 51a at its center, but the inner tube 51a may be provided radially eccentrically from the center of the outer tube 51b.

[0063] Furthermore, in the above embodiment, an example has been given of using the air heater 56 that supplies air heated by compression without using electricity or fire, but an electric heater or the like that heats the air may be provided outside the explosion-proof zone, and the heated air may be passed through the air supply pipe 52 into the supply path 33.

[0064] In addition, in the above embodiment, the paint temperature adjustment device 50 is provided between the first pressure sensor (PS1) 37 of the supply path 33 and the first three-way valve 38, but it may be provided at any other position as long as it is capable of heating the paint.

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

[0066] Furthermore, in the above embodiment, the inner tube 51a and the outer tube 51b have circular cross sections, but they may have shapes other than circular.

[0067] [Supplementary explanation of the embodiment] The above-described embodiments each show a preferred specific example of the present invention. The numerical values, components, arrangement positions of the components, order of connection, etc. shown in the above-described embodiments are merely examples and are not intended to limit the present invention. Furthermore, the drawings are not necessarily strict illustrations.

[0068] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0069] The above-described series of processes can be executed by hardware or software. When the series of processes are executed by software, the programs constituting the software are installed from a program recording medium into a computer incorporated in dedicated hardware, or into, for example, a general-purpose computer that can execute various functions by installing various programs.

[0070] The program executed by the computer may be a program that processes in chronological order according to the order described in this specification, or may be a program that processes in parallel or at the required timing, such as when called.

[0071] [Note] The contents of the above-described embodiments can be understood, for example, as follows.

[0072] (1) Multiple tubes The device comprises a paint head 32 that ejects paint onto an object to be painted, a supply path 33 that is provided in an explosion-proof zone and supplies paint toward the paint head 32, a double pipe 51 that is interposed midway along the supply path 33 and has a double structure consisting of an inner pipe 51a and an outer pipe 51b, the inner pipe 51a being connected to the supply path 33, and air flowing through an outer pipe flow path 51c that 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 flow path 51c.

[0073] As a result, the temperature of the paint heading to the paint head 32 is regulated by heat exchange with air along the supply path 33, making it possible to regulate the paint temperature even in explosion-proof zones and maintain stable paint discharge performance. Furthermore, because air is used for heat exchange, expensive control equipment for explosion-proof environments is not required, reducing costs. Furthermore, regulating the paint temperature makes it possible to maintain the paint's viscosity at an appropriate level, which enables improved paint quality when painting objects such as vehicles.

[0074] Air or an inert fluid may flow through the outer pipe flow path 51c of the double pipe 51.

[0075] This not only provides high explosion-proof performance, but also reduces the weight of the fluid flowing through the outer pipe flow path 51c, thereby reducing the weight of the double pipe 51 during painting and improving the flexibility of the position where it is installed in the supply path 33. Also, because air is lightweight, the pump load when flowing through the outer pipe flow path 51c is reduced, allowing the use of a smaller pump. Furthermore, if air is partially introduced into the air supply pipe 52 from a device that supplies air to the paint circulation path 30 for cleaning, air can be sent to the air supply pipe 52 without the need for a new pump. Therefore, the weight of the entire paint temperature adjustment device 50 can be reduced.

[0076] (2) Heating or cooling The control unit 100 may control the temperature of the air so that it is different from the temperature of the paint in the supply path 33 .

[0077] This increases the temperature of the paint and reduces its viscosity, improving the discharge performance from the paint head 32. In addition, because the paint is heated using air, the paint can be heated safely even in an explosion-proof zone.

[0078] The temperature of the paint can also be lowered by setting the air temperature lower than the temperature of the paint in the supply line 33. When the temperature inside the paint booth is high, the paint temperature becomes almost the same as the ambient temperature, causing the paint temperature to rise. In such cases, the paint can be kept at the desired viscosity by cooling it.

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

[0080] This ensures the heat insulating properties of the outer pipe 51b, and also allows the outer pipe 51b to follow shape changes due to its bendability, even in areas where the supply path 33 is bent or where bending loads are applied during painting, thereby improving the freedom of the location where the double pipe 51 is installed.

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

[0082] This increases the surface area of ​​the entire inner tube 51a, thereby improving the heat exchange efficiency between the paint flowing inside each inner tube 51a and the air flowing through the outer tube flow path 51c, and allowing the paint temperature to be adjusted more efficiently.

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

[0084] This allows the inner pipe 51a to 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 in the circumferential direction from being blocked by deformation of the inner pipe 51a. This prevents a decrease in the efficiency of heat exchange between the paint flowing inside the inner pipe 51a and the air flowing through the outer pipe flow path 51c, making it possible to more efficiently adjust the paint temperature. [Explanation of symbols]

[0085] 10 Vehicle painting machine 32 Painting head 33 Supply path (supply pipe) 50 Paint temperature control device 51 Double pipe 51a Inner tube 51c Outer tube flow path 54 Joint 100 control section

Claims

1. an inkjet type painting head that ejects paint onto the object to be painted; a supply pipe provided in an explosion-proof zone for supplying the paint toward the painting head; a multi-layer pipe interposed in the middle of the supply pipe and having a multiple structure 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 an outer pipe flow path which is a gap between the inner pipe and the outer pipe; a bypass flow path that allows the paint downstream of the multiple pipes in the supply pipe to bypass the paint head and flow to the downstream side of the paint head; a control unit for controlling the temperature and flow rate of the air or the inert fluid flowing through the outer pipe flow path, The flow rate is set based on a temperature difference of the air or the inert fluid between the inlet and the outlet of the multi-pipe. A paint temperature control device characterized by the above.

2. An inkjet type painting head that ejects paint onto an object to be painted; a supply pipe provided in an explosion-proof zone for supplying the paint toward the painting head; a multi-layer pipe interposed in the middle of the supply pipe and having a multiple structure 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 an outer pipe flow path which is a gap between the inner pipe and the outer pipe; an air supply pipe connected to the upstream side of the outer pipe flow path; an air heater that is disposed in the air supply pipe and heats the air or the inert fluid by the pressure of the air or the inert fluid that is pressure-fed from an upstream side; a control unit for controlling the temperature and flow rate of the air or the inert fluid flowing through the outer pipe flow path, The flow rate is set based on a temperature difference of the air or the inert fluid between the inlet and the outlet of the multi-pipe. A paint temperature control device characterized by the above.

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

4. The paint temperature control device according to claim 1 or 2, The outer tube is formed from a resin. A paint temperature control device characterized by the above.

5. The paint temperature control device according to claim 1 or 2, 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 above.

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