Electrodeposition coating apparatus and electrodeposition coating method

Abstract

To provide an electrodeposition coating apparatus and an electrodeposition coating method with improved productivity.SOLUTION: The electrodeposition coating device includes a first temperature adjustment unit configured to adjust a temperature of the electrodeposition paint in the electrodeposition tank to a first temperature, a second temperature adjustment unit configured to adjust the temperature of the electrodeposition paint to a second temperature higher than the first temperature, and a control device configured to control opening and closing of a plurality of valves provided in a plurality of pipes connecting the first and second temperature adjustment units and the electrodeposition tank based on a specification of the object to be coated. The electrodeposition coating material whose temperature is adjusted to each of the first and second temperatures is jetted into the electrodeposition bath from each of a plurality of nozzles provided corresponding to each of the plurality of valves, when the object to be coated includes a first portion and a second portion having different electric resistances when viewed from the power supply device, and the electric resistance of the first portion is higher than the electric resistance of the second portion, the nozzle selected to jet the electrodeposition paint at the second temperature is arranged closer to the first portion than the nozzle selected to jet the electrodeposition paint at the first temperature.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to an electrodeposition coating apparatus and an electrodeposition coating method. [Background technology]

[0002] Electrodeposition coating is a coating method in which the object to be coated is immersed in paint, and a voltage is applied between the object and the other electrode in the paint, electrochemically depositing a coating film. The bag-like structure enclosed on both sides is called the "bag structure," and the ease with which a coating film adheres to the inside of this intricate bag structure is called throwing power. Because the entire object comes into contact with the paint, electrodeposition coating has the advantage of superior throwing power compared to other coating methods such as solvent coating and powder coating. Furthermore, because the film thickness is controlled by controlling the voltage or current, it is easy to achieve a uniform film thickness, and automation is also easy, making it commonly used for painting large, complex objects such as automobile bodies.

[0003] While electrodeposition coating excels in film thickness uniformity, it may not be possible to achieve a uniform coating depending on the specifications and shape of the object being coated. For example, in the case of an object having a pocket structure, such as a switchboard housing, the film thickness tends to be thinner on the inside than on the outside of the pocket structure. A thin film thickness can lead to reduced corrosion resistance and insufficient performance. A conventional electrodeposition coating method and coating device that addresses this problem describes a method in which an auxiliary electrode is provided near the area where a thick film is desired (see, for example, Patent Document 1). Another conventional electrodeposition coating method that addresses a similar problem describes a method in which the area of ​​the object to be coated where a thick film is desired is preheated before electrodeposition coating (see, for example, Patent Document 2). Furthermore, in production sites, for objects that have a bag structure, where the film thickness is uneven within the same object, the problem is addressed by repairing it in a post-process, such as by hand painting after electrodeposition coating. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 163297 / 1983 [Patent Document 2] Japanese Unexamined Patent Publication No. 63-199898 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the conventional electrodeposition coating method and coating device disclosed in the aforementioned Patent Document 1, when applied to, for example, multi-product production, it is practically difficult to position the auxiliary electrodes in accordance with the shapes of all of the objects to be coated so that they do not interfere with each other, taking into account the interference between the objects to be coated and the electrodes.Furthermore, with the conventional electrodeposition coating method disclosed in the aforementioned Patent Document 2, when it is desired to create a temperature difference between the front and back of a single plate such as a bag structure, it is difficult to suppress heat conduction, and this is not practical. Furthermore, conventional production site solutions have had the problem of adding an additional repair process after electrodeposition coating, which increases the number of processes compared to coating items that do not require a repair process, thereby reducing productivity. Possible methods for further increasing the film thickness include increasing the applied voltage or extending the coating time, but it is difficult to increase the film thickness locally, and in areas where the film is prone to deposition, there is a possibility of pinhole defects due to the generation of excessive electrolytic gas.

[0006] The present disclosure discloses a technology for solving the above-mentioned problems, and aims to provide an electrodeposition coating apparatus and an electrodeposition coating method that can obtain a coating film with a uniform thickness and improve productivity. [Means for solving the problem]

[0007] The electrodeposition coating apparatus of the present disclosure comprises an electrodeposition tank containing an electrodeposition paint, an electrode disposed in the electrodeposition tank, a power supply unit that applies a voltage between the electrode and an object to be coated immersed in the electrodeposition paint, a first temperature adjustment unit that adjusts the temperature of the electrodeposition paint to a first temperature, a second temperature adjustment unit that adjusts the temperature of the electrodeposition paint to a second temperature higher than the first temperature, a plurality of pipes that connect the first and second temperature adjustment units to the electrodeposition tank, and a control device that controls opening and closing of a plurality of valves provided in a plurality of the pipes based on the specifications of the object to be coated. The electrodeposition paint, the temperature of which is adjusted each time, is sprayed into the electrodeposition tank from a plurality of nozzles provided corresponding to each of the plurality of valves, and when the object to be coated has a first portion and a second portion which have different electrical resistances as viewed from the power supply unit, and the electrical resistance of the first portion is higher than the electrical resistance of the second portion, the nozzle selected to spray the electrodeposition paint at the second temperature is positioned closer to the first portion than the nozzle selected to spray the electrodeposition paint at the first temperature. The electrodeposition coating apparatus of the present disclosure comprises an electrodeposition tank containing an electrodeposition paint, an electrode disposed in the electrodeposition tank, a power supply unit that applies a voltage between the electrode and an object to be coated immersed in the electrodeposition paint, a first temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a first temperature, a second temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a second temperature higher than the first temperature, a plurality of pipes that connect the first and second temperature adjusting units to the electrodeposition tank, and a control unit that controls opening and closing of a plurality of valves provided in a plurality of the pipes based on the specifications of the object to be coated, and The electrocoating paint is configured to be sprayed into the electrocoating tank from a plurality of nozzles each provided corresponding to a plurality of the valves, the object to be coated has a bag structure surrounded on the sides and top, the object to be coated has a first portion which is inside the bag structure and a second portion which is outside the bag structure, the electrode is arranged on the outside of the bag structure of the object to be coated, and the nozzle selected to spray the electrocoating paint at the second temperature is positioned closer to the first portion than the nozzle selected to spray the electrocoating paint at the first temperature. The electrodeposition coating method of the present disclosure is an electrodeposition coating method in which a voltage is applied by a power supply device between an object to be coated immersed in an electrodeposition tank containing an electrodeposition paint and an electrode disposed in the electrodeposition tank to form a coating film, the method comprising the steps of: immersing the object to be coated in the electrodeposition paint; adjusting the temperature of the electrodeposition paint to a first temperature by a first temperature adjusting unit; adjusting the temperature of the electrodeposition paint to a second temperature higher than the first temperature by a second temperature adjusting unit; and controlling the opening and closing of a plurality of valves provided in a plurality of pipes connecting the first and second temperature adjusting units to the electrodeposition tank based on the specifications of the object to be coated. and a step of spraying the electrodeposition paint, the temperatures of which have been adjusted to the first and second temperatures, into the electrodeposition tank from a plurality of nozzles provided corresponding to each of the plurality of valves, wherein, when the object to be coated has a first portion and a second portion having different electrical resistances as viewed from the power supply unit, and the electrical resistance of the first portion is higher than the electrical resistance of the second portion, the step of bringing the nozzle selected to spray the electrodeposition paint at the second temperature closer to the first portion than the nozzle selected to spray the electrodeposition paint at the first temperature. Furthermore, the electrodeposition coating method of the present disclosure is an electrodeposition coating method in which a voltage is applied by a power supply device between an object to be coated immersed in an electrodeposition tank containing an electrodeposition paint and an electrode disposed in the electrodeposition tank to form a coating film, the method comprising the steps of: immersing the object to be coated in the electrodeposition paint; adjusting the temperature of the electrodeposition paint to a first temperature by a first temperature adjustment unit; adjusting the temperature of the electrodeposition paint to a second temperature higher than the first temperature by a second temperature adjustment unit; controlling, by a control device, the opening and closing of a plurality of valves provided in a plurality of pipes connecting the first and second temperature adjustment units to the electrodeposition tank based on the specifications of the object to be coated; The method includes a step of spraying the electrodeposition paint, each adjusted to the second temperature, into the electrodeposition tank from a plurality of nozzles provided corresponding to each of the plurality of valves, wherein the object to be coated has a bag structure surrounded on the sides and top, the object to be coated has a first portion which is inside the bag structure and a second portion which is outside the bag structure, the electrode is arranged on the outside of the bag structure of the object to be coated, and an electrodeposition coating device is used in which the nozzle selected to spray the electrodeposition paint at the second temperature is positioned closer to the first portion than the nozzle selected to spray the electrodeposition paint at the first temperature. [Effects of the Invention]

[0008] According to the electrodeposition coating apparatus and electrodeposition coating method of the present disclosure, a coating film with a uniform thickness can be obtained, and an electrodeposition coating apparatus and electrodeposition coating method with improved productivity can be obtained. [Brief explanation of the drawings]

[0009] [Figure 1A] 1 is an overall configuration diagram showing an electrodeposition coating apparatus according to a first embodiment. [Figure 1B] 1 is a flowchart showing an electrodeposition coating method according to the first embodiment. [Figure 2] 4 is a graph showing the change in film thickness with respect to the paint temperature and current application time of the electrodeposition coating device according to the first embodiment. [Figure 3A]FIG. 10 is a diagram showing a part of the overall configuration of an electrodeposition coating apparatus according to a second embodiment. [Figure 3B] FIG. 10 is a diagram showing a part of the overall configuration of an electrodeposition coating apparatus according to a second embodiment. [Figure 3C] FIG. 10 is a diagram showing a part of the overall configuration of an electrodeposition coating apparatus according to a second embodiment. [Figure 4] FIG. 10 is an overall configuration diagram showing an electrodeposition coating apparatus according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the first embodiment will be described with reference to the drawings. In each drawing, the same reference numerals indicate the same or corresponding parts.

[0011] Embodiment 1 1A is an overall configuration diagram showing an electrodeposition coating apparatus according to embodiment 1. As shown in Fig. 1A, the electrodeposition coating apparatus 100 according to embodiment 1 includes an electrodeposition tank 2 containing an electrodeposition paint 1, an electrode 4 disposed in the electrodeposition tank 2, a power supply 5 for applying a voltage between the electrode 4 and an object 3 to be coated immersed in the electrodeposition paint 1, a heat exchanger 6a serving as a first temperature adjusting unit for adjusting the temperature of the electrodeposition paint 1 to a first temperature, which is a temperature of standard processing conditions, a heat exchanger 6b serving as a second temperature adjusting unit for adjusting the temperature of the electrodeposition paint 1 to a second temperature higher than the first temperature, which is a temperature about 10°C higher than the standard processing conditions, a first pipe 17a, a second pipe 17b, and a third pipe 17 serving as a plurality of pipes connecting the first and second temperature adjusting units to the electrodeposition tank 2, and a plurality of pipes provided in the first pipe 17a, the second pipe 17b, and the third pipe 17 based on the specifications of the object 3 to be coated. The apparatus is equipped with a control device 10 that controls the opening and closing of valve 9, a first valve 9a, and a second valve 9b, and is configured so that standard temperature paint 19, which is an electrocoating paint adjusted to the first and second temperatures, and heated paint 18, are sprayed into the electrocoating tank 2 from each of a plurality of nozzles 7 provided corresponding to each of the plurality of valves 9.The object to be coated 3 has a first portion and a second portion which have different electrical resistances as seen from the power supply 5, and when the electrical resistance of the first portion is higher than the electrical resistance of the second portion, the nozzle 7 selected to spray heated paint 18, which is an electrocoating paint at the second temperature, is positioned closer to the first portion than the nozzle 7 selected to spray standard temperature paint 19, which is an electrocoating paint at the first temperature.

[0012] 1A, an electrodeposition tank 2 is filled with electrodeposition paint 1, and an electrodeposition coating apparatus 100 is equipped with a temperature control system 8a that sets the temperature to standard processing conditions, and a temperature control system 8b that sets the temperature to about 10°C higher than the standard processing conditions. The electrodeposition paint 1, whose temperature has been controlled by each temperature control system, is sprayed from a nozzle 7 disposed at the bottom of the electrodeposition tank 2 during electrodeposition coating of an object 3 to be coated. In the electrodeposition coating apparatus 100 of embodiment 1, heated paint 18, which is electrodeposition paint 1 whose temperature is controlled by a temperature control system 8b that sets the temperature about 10°C higher than the standard processing conditions, is sprayed onto areas of the object 3 where a coating film is difficult to deposit, thereby adjusting the reaction temperature during electrodeposition coating, and, for example, it is possible to obtain a coating film of uniform thickness without any film thickness variation within the same object 3 to be coated.

[0013] Electrodeposition coating is a coating method in which the workpiece 3 is immersed in electrodeposition paint 1, and a voltage is applied between the workpiece 3 as one electrode and the other electrode 4 in the electrodeposition paint 1, electrochemically depositing a coating film. Coating deposition occurs preferentially in areas with low electrical resistance as seen from the power supply 5. However, the deposition rate of the coating film slows in areas far from the electrode 4, where the solution resistance of the electrodeposition paint 1 is high, where low-conductivity materials are used, or where contact resistance occurs due to fastening parts, etc. For example, in a workpiece 3 with a pouch structure such as a switchboard housing, the charge must circulate inside the pouch structure, which increases the solution resistance of the electrodeposition paint 1 and results in a thin coating film.

[0014] In the first embodiment, the object 3 to be coated is described as a switchboard housing having a bag structure that is enclosed on the sides and top. In the electrodeposition coating apparatus 100 in the first embodiment, the electrodeposition tank 2 is disposed below a conveying device 12 that conveys the object 3 to be coated while suspended by a hanger 11a. The object 3 to be coated is immersed while suspended by the hanger 11a from the conveying device 12 disposed above the electrodeposition tank 2. The electrodeposition tank 2 is large enough to contain the entire object 3 to be coated, and its top is open so that the object 3 can be loaded and unloaded. Within the electrodeposition tank 2, an electrode 4 that pairs with the object 3 to be coated is disposed along the wall of the electrodeposition tank 2, and the electrodeposition tank 2 contains an amount of electrodeposition paint 1 that can completely immerse the object 3 to be coated.

[0015] A diaphragm electrode is provided as electrode 4 to collect the acid generated as the coating film is deposited. A power supply 5 capable of supplying direct current is provided in the electrical circuit between the workpiece 3 and electrode 4, and a voltage is applied for a fixed period of time by controlling the voltage or current, with the workpiece 3 acting as the cathode and the electrode 4 acting as the anode. Electrodeposition paint 1 overflows from above electrodeposition tank 2, and overflow tank 13, which receives the overflow, is located adjacent to electrodeposition tank 2. Electrodeposition paint 1 received in overflow tank 13 is sucked by pump 15 outside the tank through suction port 14 on the bottom of overflow tank 13. After dust particles are removed by filter 16, the temperature is adjusted to the standard processing conditions in heat exchanger 6a, and the paint passes through first pipe 17a and third pipe 17 and is sprayed into electrodeposition tank 2 from nozzle 7 at the bottom as standard-temperature paint 19. This is temperature control system 8a, which sets the temperature for the standard processing conditions. Temperature control system 8a, which sets the temperature for the standard processing conditions, is equipped with dedicated pump 15, filter 16, heat exchanger 6a, and first pipe 17a. First pipe 17a is also equipped with first valve 9a.

[0016] The electrodeposition coating apparatus 100 according to the first embodiment is also provided with a temperature control system 8b that sets the temperature about 10°C higher than the standard processing conditions, separate from the temperature control system 8a that sets the temperature for the standard processing conditions. The temperature control system 8b that sets the temperature about 10°C higher than the standard processing conditions is provided with a dedicated pump 15, filter 16, heat exchanger 6b, and second piping 17b that are separate from the temperature control system 8a that sets the temperature for the standard processing conditions. The second piping 17b is also provided with a second valve 9b. The electrodeposition paint 1 received in the overflow tank 13 is sucked in by a pump 15 outside the tank through a suction port 14 provided on the bottom of the overflow tank 13, and after dust particles are removed by a filter 16, the temperature is adjusted in a heat exchanger 6b to a temperature about 10°C higher than the standard processing conditions, and the paint passes through a second pipe 17b and a third pipe 17 and is sprayed as heated paint 18 into the electrodeposition tank 2 from a nozzle 7 provided on the bottom of the electrodeposition tank 2. The supply of the standard temperature paint 19 and the heated paint 18 is adjusted by a control device 10 controlling the opening and closing of a first valve 9a and a second valve 9b, for example, with a time difference. The electrodeposition coating apparatus 100 according to embodiment 1 includes an overflow tank 13 arranged adjacent to the electrodeposition tank 2, and the electrodeposition paint 1 is supplied to the heat exchanger 6a, which is the first temperature adjustment unit, and the heat exchanger 6b, which is the second temperature adjustment unit, via an intake port 14 provided in the overflow tank 13.

[0017] Temperature control system 8b, which sets the temperature approximately 10°C higher than the standard processing conditions, shares an overflow tank 13 with temperature control system 8a, which sets the temperature for the standard processing conditions. Multiple nozzles 7, which spray electrodeposition paint 1 from each temperature control system into electrodeposition tank 2, are located on the bottom of electrodeposition tank 2. The spray of electrodeposition paint 1 is switched on and off by opening and closing valves 9 directly below nozzles 7. The opening and closing of valves 9 is controlled by control device 10, which selects a nozzle 7 at an appropriate position based on the specifications of the workpiece 3. Furthermore, control device 10 controls the spray range of electrodeposition paint 1, adjusted to a first temperature (standard processing conditions) or a second temperature (approximately 10°C higher than the first temperature) for the standard processing conditions, i.e., the spray range of standard-temperature paint 19 or heated paint 18, by opening and closing valves 9 and selecting nozzles 7. The flow rate and flow velocity of these paints are also controlled. The specifications of workpiece 3 include its shape, structure, components, dimensions, etc.

[0018] The configuration of the electrodeposition coating apparatus 100 according to the first embodiment makes it possible to perform electrodeposition coating by jetting heated paint 18 onto areas of the workpiece 3 where a coating film is difficult to deposit. Generally, in electrodeposition coating, the electrodeposition paint 1 is constantly stirred in the electrodeposition tank 2 to prevent paint pigment settling, to disperse uniformly, and to bring fresh electrodeposition paint 1 into contact with the workpiece 3 during coating, and these temperature control systems also play a role in stirring the paint. Furthermore, the nozzle 7 is shared between the temperature control system 8a, which sets the temperature at standard processing conditions, and the temperature control system 8b, which sets the temperature at a temperature approximately 10°C higher than the standard processing conditions.

[0019] The temperature-controlled electrodeposition paint 1 is sprayed in the area that matches the specifications of the workpiece 3, with heated paint 18 being selected by the control device 10 for each temperature control system, and standard temperature paint 19 being sprayed in other areas. This makes it possible to accommodate a variety of specifications for workpieces 3 with the same number of nozzles, compared to using dedicated nozzles 7 for each temperature control system.

[0020] As described above, in the electrodeposition coating apparatus 100 according to embodiment 1, the multiple pipes include the first pipe 17a and the second pipe 17b connected to the heat exchanger 6a, which is the first temperature adjustment unit, and the heat exchanger 6b, which is the second temperature adjustment unit, respectively, and the third pipe 17 branched from the first pipe 17a and the second pipe 17b and connected to the electrodeposition tank 2, and the multiple nozzles 7 are shared by the electrodeposition paint adjusted to a first temperature by the heat exchanger 6a, which is the first temperature adjustment unit, i.e., standard temperature paint 19, and the electrodeposition paint adjusted to a second temperature by the heat exchanger 6b, which is the second temperature adjustment unit, i.e., heated paint 18.

[0021] Next, an electrodeposition coating method using the electrodeposition coating apparatus 100 described above will be described. FIG. 1B is a flowchart showing the electrodeposition coating method according to the first embodiment. The electrodeposition coating method according to the first embodiment is characterized in that, in the electrodeposition coating process in which a voltage is applied between an object 3 to be coated immersed in an electrodeposition coating material 1 and an electrode 4 also immersed in the electrodeposition coating material 1 to form a coating film, when there are areas within the same object 3 where the electrical resistance as seen from the power supply 5 varies, the areas with higher electrical resistance are coated while being brought into contact with the electrodeposition coating material 1 at a higher temperature. In the first embodiment, a tactile conveying device 12 is used as the conveying device 12, and the following description will be given assuming the use of a tactile conveying device 12, but this is not limited to this. Rails 11b of the conveying device 12 are provided above the electrodeposition tank 2, and the object 3 to be coated, such as a switchboard housing, is hung from a hanger 11a and transported to each process by the conveying device 12 with the open side facing downward.

[0022] First, as shown in FIG. 1B, before the workpiece 3 is immersed in the electrodeposition paint 1, in the first step, the specifications of the workpiece 3 are input into the control device 10 (S101). After the workpiece 3 has been subjected to pretreatments such as degreasing, washing with water, and chemical conversion treatment, it is carried to above the electrodeposition tank 2. In the second step, the workpiece 3 is immersed in the electrodeposition paint 1 together with the hanger 11a (S102). After the entire workpiece 3 is immersed in the electrodeposition paint 1, in the third step, electricity is turned on, and simultaneously, the heated paint 18 and the standard-temperature paint 19 are started to be sprayed (S103). As mentioned above, the specifications of the workpiece 3 are input into the control device 10 before the electrodeposition coating, and the electrodeposition paint 1 is sprayed in an area appropriate for the specifications of the workpiece 3. The heated paint 18 is sprayed on areas with high electrical resistance that make it difficult for a paint film to deposit, and the standard-temperature paint 19 is sprayed on areas with low electrical resistance that make it easy for a paint film to deposit. In the switchboard housing, the area where the paint film is difficult to deposit is the inside of the bag structure. Heated paint 18 is sprayed onto the inside of the bag structure, while standard temperature paint 19 is sprayed onto other areas, such as the outside of the bag structure.

[0023] This promotes localized deposition of the coating film in areas where deposition is difficult, thereby suppressing uneven film thickness within the same object 3. After a predetermined time has elapsed, in the fourth step, the current is stopped and, at the same time, the jet of heated paint 18 is stopped (S104), and in the fifth step, the object 3 is removed from the electrodeposition paint 1 (S105). By minimizing the jet of heated paint 18, the temperature of the electrodeposition paint 1 throughout the electrodeposition tank 2 is prevented from rising more than necessary. Then, in the sixth step, excess electrodeposition paint 1 adhering to the object 3 is washed away using water washing equipment, and the coating is baked and hardened (S106), completing the electrodeposition coating process.

[0024] FIG. 2 is a graph showing the change in film thickness versus paint temperature and current application time in the electrodeposition coating apparatus according to the first embodiment. The significance of spraying temperature-controlled electrodeposition paint 1 in the first embodiment will be explained below with reference to FIG. 2. Generally, electrodeposition paint 1 is typically processed at a standard temperature of 28°C. For example, in an actual production line for a distribution board enclosure, the temperature is controlled within a range of ±1°C. Electrodeposition coating is a coating method in which a coating film is deposited through a chemical reaction. Temperature significantly affects the reaction rate, i.e., the deposition properties of the coating film, and therefore strict control is required to maintain consistent quality. FIG. 2 shows the change in film thickness versus current application time when painting is performed at paint temperatures of 24°C and 15°C, with the exception of the temperature of the electrodeposition paint 1. The longer the current application time, the greater the difference in film thickness between the two. After 120 seconds of painting, the film thickness at a paint temperature of 24°C was 14 μm, while the film thickness at a paint temperature of 15°C was 7 μm, approximately double the difference.

[0025] Furthermore, no significant difference in the appearance of the coating was observed. A temperature difference greater than this is expected to affect the appearance, such as the occurrence of pinholes, so by controlling the reaction temperature during electrodeposition coating using temperature control system 8b, which sets the temperature about 10°C higher than the standard processing conditions, it is possible to promote or suppress the deposition of the coating while maintaining smoothness and control the film thickness. The electrodeposition coating apparatus 100 may have a configuration other than that described above. For example, the electrode 4 may be disposed on the bottom surface of the electrodeposition tank 2, not necessarily on the wall surface, or on both the wall surface and the bottom surface. The overflow tank 13 may be disposed on any of the inlet side, outlet side, or side of the electrodeposition tank 2, and the nozzle 7 may be disposed on the wall surface, not necessarily on the bottom of the electrodeposition tank 2. Furthermore, the temperature adjustment unit that adjusts the temperature is not limited to a heat exchanger, and may be anything that can heat the paint, such as a heater.

[0026] In the first embodiment, the electrodeposition coating apparatus 100 is described as having a common nozzle 7 regardless of the temperature control system, but a configuration having an individual nozzle 7 for each temperature control system is also possible. Also, in the first embodiment, cationic electrodeposition coating is described, but anionic electrodeposition coating is also applicable. Also, in the first embodiment, the object to be coated 3 is described as being the same, but it does not necessarily have to be the same and may be different.

[0027] As described above, the electrodeposition coating method according to the first embodiment is an electrodeposition coating method in which a voltage is applied by a power supply 5 between an object to be coated immersed in an electrodeposition tank 2 containing an electrodeposition paint 1 and an electrode 4 disposed in the electrodeposition tank 2 to form a coating film, and includes the steps of: immersing the object to be coated 3 in the electrodeposition paint 1; adjusting the temperature of the electrodeposition paint 1 to a first temperature, which is a temperature of standard processing conditions, by a heat exchanger 6a, which is a first temperature adjusting unit; adjusting the temperature of the electrodeposition paint 1 to a second temperature, which is higher than the first temperature, by a heat exchanger 6b, which is a second temperature adjusting unit, to a temperature about 10°C higher than the standard processing conditions; the step of controlling the opening and closing of valves 9, first valve 9a, and second valve 9b, which are a plurality of valves connected to a control device 10; the step of spraying standard temperature paint 19, which is an electrodeposition paint adjusted to a first temperature, and heated paint 18, which is an electrodeposition paint adjusted to a second temperature, into electrodeposition tank 2 from a plurality of nozzles 7 provided corresponding to each of the plurality of valves 9; and when the object to be coated 3 has a first portion and a second portion which have different electrical resistances as viewed from power supply 5, and the electrical resistance of the first portion is higher than the electrical resistance of the second portion, the step of bringing nozzle 7 selected to spray heated paint 18, which is an electrodeposition paint at the second temperature, closer to the first portion than nozzle 7 selected to spray standard temperature paint 19, which is an electrodeposition paint at the first temperature.

[0028] In addition, the electrodeposition coating method according to embodiment 1 includes, after the step of immersing the object to be coated 3 in the electrodeposition paint 1, a step of spraying the electrodeposition paint heated to a second temperature, i.e., the paint 18 heated to the second temperature, toward the first part, and after the object to be coated 3 is removed from the tank, a step of stopping the spraying of the electrodeposition paint heated to the second temperature, i.e., the heated paint 18.

[0029] Furthermore, the electrodeposition coating method according to embodiment 1 includes a step of inputting the specifications of the object to be coated 3 into the control device 10 before the step of immersing the object to be coated 3 in the electrodeposition paint 1, and after the object to be coated 3 is placed in the tank, electrodeposition paint heated to a second temperature, i.e., heated paint 18, is sprayed from a plurality of nozzles 7 selected according to the specifications of the object to be coated 3, i.e., arranged within the spray range of the electrodeposition paint 1. As described above, according to the electrodeposition coating method of the first embodiment, heated paint 18 is sprayed from the nozzle 7 at a suitable position according to the specifications and shape of the workpiece 3, thereby promoting localized deposition of the coating film in areas where deposition is difficult. This makes it possible to obtain a coating film of uniform thickness regardless of the specifications and shape of the workpiece 3, without increasing the number of steps and reducing productivity, and while maintaining the smoothness of the coating film.

[0030] Embodiment 2 3A to 3C are diagrams showing a part of the overall configuration of an electrodeposition coating apparatus according to embodiment 2, with FIG. 3A showing the state when the inner wall surface of the bag structure portion of the switchboard housing is transported above nozzle 7a, and FIG. 3B showing the overflow tank of the electrodeposition coating apparatus of FIG. 3A. Also, FIG. 3C shows the state when the inner wall surface of the bag structure portion of the switchboard housing is transported above nozzle 7b. The overflow tank corresponding to the electrodeposition coating apparatus of FIG. 3C has the same configuration as that of FIG. 3B, and is therefore not shown. 3A to 3C, the same reference numerals as those used in the description of embodiment 1 indicate the same configurations, and the description thereof will be omitted. The electrodeposition coating apparatus 100 according to embodiment 2 will be described below, focusing on the configurations different from embodiment 1. In the electrodeposition coating apparatus 100 according to the first embodiment, the case where the transport device 12 is of the tactile type has been described, but in the second embodiment, a case where a trolley-type transport device 12 is used will be described. Furthermore, with the tactile type transport device 12, the workpiece 3 does not move during coating, but when the trolley-type transport device 12 is used, the workpiece 3 moves within the electrodeposition tank 2 during coating, as shown in Figures 3A to 3C.

[0031] The difference between embodiment 2 and embodiment 1 is that embodiment 1 uses a tactile electrodeposition tank 2, while embodiment 2 uses a trolley electrodeposition tank 2. Also, embodiment 1 differs in that the spray range of the electrodeposition paint 1 is fixed during coating, whereas embodiment 2 differs in that the spray range of the electrodeposition paint 1 moves in accordance with the movement of the workpiece 3. In embodiment 2, the workpiece 3 will be described as a switchboard housing having a bag structure that is enclosed on the sides and top. In the first embodiment, the electrodeposition tank 2 is large enough to accommodate the entire workpiece 3, and has an open top to allow the workpiece 3 to enter and exit the tank. However, in the second embodiment, in addition to the above, the electrodeposition tank 2 is extended in the direction in which the workpiece 3 is transported, and is designed to be energized for a predetermined period of time while it is transported through the electrodeposition tank 2. Furthermore, the rails 11b of the transport device 12 are inclined downward on the entry side and upward on the exit side. The workpiece 3 enters and leaves the electrodeposition tank 2 using these rails 11b, and to prevent contact between the workpiece 3 and the electrodeposition tank 2, the entry side is inclined downward at an angle of 20 to 40 degrees, and the exit side is inclined upward at an angle of 20 to 40 degrees.

[0032] If the workpiece 3 moves during painting, the temperature-controlled paint's spray range must also change accordingly to achieve the desired effect. In the first embodiment, information about the specifications and shape of the workpiece 3 is input to the control device 10 before electrodeposition painting, and the paint is sprayed in an area appropriate for the specifications and shape of the workpiece 3. In the second embodiment, in addition to the above, the spraying nozzle 7 is changed successively as the workpiece 3 moves, thereby shifting the spray range. As the workpiece 3 (distribution board housing) enters the electrodeposition tank 2 and is transported, heated paint 18 is sprayed from nozzle 7a when the inner wall surface of the bag-shaped portion is above nozzle 7a. Further transport occurs, and when the inner wall surface of the bag-shaped portion is above nozzle 7b, heated paint 18 is sprayed from nozzle 7b. Nozzle 7a stops spraying heated paint 18 and sprays standard-temperature paint 19.

[0033] In other words, when there is a location nearby where the paint film is difficult to deposit, heated paint 18 is sprayed from the nozzle, and at other times standard temperature paint 19 is sprayed. By performing this process with each nozzle until the workpiece 3 is removed from the tank, the spray range of heated paint 18 follows the transport of the workpiece 3, and the effect of promoting paint film deposition can be obtained at all times during painting in locations where the paint film is difficult to deposit.

[0034] In the electrodeposition coating method according to embodiment 2, the control device 10 controls the selection of multiple nozzles 7 from which the paint 18 heated to the second temperature is sprayed, i.e., the spray range of the paint 18 heated to the second temperature, in accordance with the movement of the object 3 to be coated inside the electrodeposition tank 2. As described above, according to the electrodeposition coating method of the second embodiment, heated paint 18 is jetted from a nozzle at a suitable position according to the specifications and shape of the workpiece 3 and its movement within the electrodeposition tank 2, thereby promoting localized deposition of the coating film in areas where deposition is difficult, thereby making it possible to obtain a coating film of uniform thickness regardless of the specifications and shape of the workpiece 3, while maintaining the smoothness of the coating film, without increasing the number of processes and reducing productivity. Furthermore, the electrodeposition coating method of the second embodiment enables continuous assembly line work of the workpiece 3.

[0035] Embodiment 3 FIG. 4 is an overall configuration diagram showing an electrodeposition coating apparatus according to a third embodiment. In FIG. 4, components with the same reference numerals as those used in the description of the first embodiment indicate the same configuration, and their description will be omitted. In the first and second embodiments, two types of paint were used: heated paint 18 and standard temperature paint 19. However, in the third embodiment, as shown in FIG. 4, a cooled paint 20 is added, and electrodeposition coating paints 1 of three different temperatures are used. As shown in FIG. 4, the electrodeposition coating apparatus 100 in the third embodiment is characterized by including, in addition to the configuration of the first or second embodiment, another nozzle 7d from which cooled paint 20 is sprayed near the electrode 4.

[0036] In the electrodeposition coating apparatus 100 according to the third embodiment, the workpiece 3 is a switchboard housing having a bag structure enclosed on the sides and top, and the conveying device 12 is of a tactile type. The electrodeposition coating apparatus 100 according to the third embodiment is configured by adding a temperature control system 8c that sets the temperature approximately 10°C lower than the standard processing conditions to the electrodeposition coating apparatus 100 according to the first embodiment. The temperature control system 8c, which sets the temperature approximately 10°C lower than the standard processing conditions, is equipped with a dedicated pump 15, filter 16, heat exchanger 6c, and fourth pipe 17c, just like the other temperature control systems. The fourth pipe 17c is also equipped with a third valve 9c. The electrocoating paint 1 received in the overflow tank 13 is sucked in by a pump 15 outside the tank through an inlet 14 provided on the bottom of the overflow tank 13, and after debris is removed by a filter 16, the temperature is adjusted to a temperature about 10°C lower than the standard processing conditions in a heat exchanger 6c, and the cooled paint 20 is sprayed into the electrocoating tank 2 from another nozzle 7d provided on the side of the electrocoating tank 2 through a fourth pipe 17c and a fifth pipe 17d.

[0037] At this time, another nozzle 7d of the temperature control system 8c, which sets the temperature about 10°C lower than the standard processing conditions, is arranged near the electrode 4, for example, facing the electrode 4, and cooled paint 20 is sprayed onto the outside of the bag structure part of the distribution board housing. The electrodeposition coating apparatus 100 according to the third embodiment includes a heat exchanger 6c, which is a third temperature adjusting unit that adjusts the temperature of the electrodeposition paint 1 to a third temperature that is approximately 10°C lower than the standard processing temperature, which is a first temperature, a fourth pipe 17c connected to the third temperature adjusting unit, and a fifth pipe 17d that branches off from the fourth pipe 17c and is connected to the electrodeposition tank 2. The control device 10 controls the opening and closing of a third valve 9c on the fourth pipe 17c and a fourth valve 9d on the fifth pipe 17d based on the specifications of the workpiece 3. The electrodeposition paint 1 adjusted to the third temperature, i.e., the cooled paint 20, is sprayed into the electrodeposition tank 2 from another nozzle 7d provided corresponding to the fourth valve 9d. The other nozzle 7d is also provided opposite the electrode 4. The electrodeposition coating apparatus 100 according to the third embodiment has the above-described configuration, which makes it possible to apply coating while suppressing deposition of a coating film in areas near the electrode 4 where electrical resistance is low and where a coating film is likely to deposit.

[0038] Next, an electrodeposition coating method using the above-described electrodeposition coating apparatus 100 will be described with reference to FIG. 4. The electrodeposition coating method in the third embodiment is characterized by spraying cooled paint 20 onto a portion of the workpiece 3 that has low electrical resistance relative to the power supply 5. As in the first embodiment, the workpiece 3, a distribution board housing, is hung from a hanger 11a with its open side facing downward and transported to each process by a transport device 12. After pretreatments such as degreasing, water washing, and chemical conversion treatment are completed, the workpiece 3 is transported above the electrodeposition tank 2 and immersed, along with the hanger 11a, in the electrodeposition paint 1. After the entire workpiece 3 is immersed in the electrodeposition paint 1, electricity is turned on, and simultaneously, the heated paint 18, the standard temperature paint 19, and the cooled paint 20 begin to be sprayed. The spray range of each paint is determined based on the specifications of the workpiece 3 input into the control device 10 before electrodeposition coating, and the paints are sprayed in areas appropriate for the specifications and shape of the workpiece 3.

[0039] Heated paint 18 is sprayed onto areas with high electrical resistance where a coating film is difficult to deposit, cooled paint 20 onto areas with low electrical resistance where a coating film is easy to deposit, and standard temperature paint 19 onto other areas. In the switchboard housing, heated paint 18 is sprayed onto areas inside the pocket structure where a coating film is difficult to deposit, cooled paint 20 is sprayed onto areas outside the pocket structure where a coating film is easy to deposit, and standard temperature paint 19 is sprayed onto other areas. This locally promotes coating film deposition in areas where a coating film is difficult to deposit and locally suppresses coating film deposition in areas where a coating film is easy to deposit, thereby preventing uneven coating thickness within the same coated object 3. After a predetermined time has elapsed, the current is turned off, and at the same time, the spraying of heated paint 18 and cooled paint 20 is stopped, and the coated object 3 is removed from the electrodeposition paint 1. Minimizing the jet of heated paint 18 prevents the temperature of the electrodeposition paint 1 throughout the electrodeposition tank 2 from rising or falling more than necessary. After that, excess electrodeposition paint 1 adhering to the object 3 is washed away with water washing equipment, and the electrodeposition coating process is completed by baking and hardening the coating film.

[0040] Although the third embodiment has been described above with reference to the case where the tactile transport device 12 is used, a trolley transport device 12 may also be used. As described above, the electrodeposition coating method in embodiment 3 includes a step of adjusting the temperature of the electrodeposition paint 1 to a third temperature, which is lower than the first temperature, which is the temperature under the standard processing conditions, by using the heat exchanger 6c, which is the third temperature adjustment unit, to a temperature approximately 10°C lower than the standard processing conditions, and the electrodeposition paint 1 cooled to the third temperature, i.e., the cooled paint 20, is sprayed from another nozzle 7d provided opposite the electrode 4 through the fourth pipe 17c connected to the third temperature adjustment unit and the fifth pipe 17d branching off from the fourth pipe 17c and connected to the electrodeposition tank 2 onto the second part, which has low electrical resistance.

[0041] In addition, in the electrodeposition coating method of embodiment 3, electrodeposition paint cooled to a third temperature, i.e., cooled paint 20, is sprayed toward the second part, which is a part with low electrical resistance, and after the object to be coated 3 is removed from the tank, the spraying of cooled paint 20, which is electrodeposition paint cooled to the third temperature, is stopped. Furthermore, in the electrodeposition coating method of embodiment 3, the specifications of the object 3 to be coated are input into the control device 10, and after the object 3 to be coated is placed in the tank, cooled paint 20, which is an electrodeposition paint cooled to a third temperature, is sprayed from another nozzle 7d selected according to the specifications of the object 3 to be coated. As described above, according to the electrodeposition coating method of the third embodiment, heated paint 18 or cooled paint 20 is sprayed from the nozzle 7 at a suitable position according to the specifications and shape of the workpiece 3, thereby promoting localized deposition of the paint film in areas where it is difficult to deposit, and locally suppressing deposition of the paint film in areas where it is easy to deposit. This makes it possible to obtain a paint film of uniform thickness regardless of the specifications and shape of the workpiece 3, without increasing the number of steps and reducing productivity, and while maintaining the smoothness of the paint film.

[0042] The above describes in detail preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0043] Various aspects of the present disclosure are summarized below as appendices.

[0044] (Appendix 1) an electrodeposition tank containing electrodeposition paint; an electrode disposed in the electrodeposition tank; a power supply device that applies a voltage between the electrode and the object to be coated immersed in the electrodeposition paint; a first temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a first temperature; a second temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a second temperature higher than the first temperature; a plurality of pipes connecting the first and second temperature adjustment units and the electrodeposition tank; a control device that controls opening and closing of a plurality of valves provided in a plurality of the pipes based on the specifications of the object to be coated; the electrodeposition paints adjusted to the first and second temperatures are sprayed into the electrodeposition tank from a plurality of nozzles provided corresponding to the plurality of valves, An electrocoating device in which, when the object to be coated has a first portion and a second portion which have different electrical resistances as viewed from the power supply, and the electrical resistance of the first portion is higher than the electrical resistance of the second portion, the nozzle selected to spray the electrocoating paint at the second temperature is positioned closer to the first portion than the nozzle selected to spray the electrocoating paint at the first temperature. (Appendix 2) an electrodeposition tank containing electrodeposition paint; an electrode disposed in the electrodeposition tank; a power supply device that applies a voltage between the electrode and the object to be coated immersed in the electrodeposition paint; a first temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a first temperature; a second temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a second temperature higher than the first temperature; a plurality of pipes connecting the first and second temperature adjustment units and the electrodeposition tank; a control device that controls opening and closing of a plurality of valves provided in a plurality of the pipes based on the specifications of the object to be coated; the electrodeposition paints adjusted to the first and second temperatures are sprayed into the electrodeposition tank from a plurality of nozzles provided corresponding to the plurality of valves, The object to be coated has a bag structure surrounded by a side surface and a top surface, and the object to be coated has a first portion that is inside the bag structure and a second portion that is outside the bag structure, the electrode is disposed on the outside of the bag structure of the object to be coated, An electrocoating apparatus in which the nozzle selected to spray the electrocoating paint at the second temperature is positioned closer to the first portion than the nozzle selected to spray the electrocoating paint at the first temperature. (Appendix 3) an overflow tank disposed adjacent to the electrodeposition tank; 3. An electrodeposition coating apparatus according to claim 1, wherein the electrodeposition paint is supplied to the first temperature adjustment unit and the second temperature adjustment unit, respectively, through an inlet provided in the overflow tank. (Appendix 4) 4. An electrodeposition coating apparatus according to any one of claims 1 to 3, wherein the object to be coated is immersed in the electrodeposition tank while being suspended by a hanger from a conveying device provided above the electrodeposition tank. (Appendix 5) the plurality of pipes include first and second pipes connected to the first and second temperature adjustment units, respectively, and a third pipe branched from the first and second pipes and connected to the electrodeposition tank; 5. The electrodeposition coating apparatus according to claim 1, wherein the plurality of nozzles are shared by the electrodeposition paint adjusted to the first temperature by the first temperature adjustment unit and the electrodeposition paint adjusted to the second temperature by the second temperature adjustment unit. (Appendix 6) a third temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a third temperature that is lower than the first temperature; a fourth pipe connected to the third temperature adjustment unit; a fifth pipe branched from the fourth pipe and connected to the electrodeposition tank; the control device controls opening and closing of a third valve provided in the fourth pipe and a fourth valve provided in the fifth pipe based on specifications of the object to be coated; An electrodeposition coating apparatus according to any one of appendices 1 to 5, wherein the electrodeposition paint whose temperature has been adjusted to the third temperature is sprayed into the electrodeposition tank from another nozzle provided corresponding to the fourth valve. (Appendix 7) 7. The electrodeposition coating apparatus according to claim 6, wherein the other nozzle is provided opposite the electrode. (Appendix 8) An electrodeposition coating method for forming a coating film by applying a voltage from a power supply between an object to be coated immersed in an electrodeposition tank containing an electrodeposition paint and an electrode disposed in the electrodeposition tank, immersing the object to be coated in the electrodeposition paint; a step of adjusting the temperature of the electrodeposition paint to a first temperature by a first temperature adjusting unit; a step of adjusting the temperature of the electrodeposition paint to a second temperature higher than the first temperature by a second temperature adjusting unit; a step of controlling, by a control device, the opening and closing of a plurality of valves provided in a plurality of pipes connecting the first and second temperature adjustment units and the electrodeposition tank based on the specifications of the object to be coated; a step of spraying the electrodeposition paint, the temperature of which has been adjusted to the first and second temperatures, into the electrodeposition tank from a plurality of nozzles provided corresponding to each of the plurality of valves, an electrodeposition coating method comprising the steps of: when the object to be coated has a first portion and a second portion having different electrical resistances as viewed from the power supply device, and the electrical resistance of the first portion is higher than the electrical resistance of the second portion, bringing the nozzle selected to spray the electrodeposition paint at the second temperature closer to the first portion than the nozzle selected to spray the electrodeposition paint at the first temperature. (Appendix 9) An electrodeposition coating method for forming a coating film by applying a voltage from a power supply between an object to be coated immersed in an electrodeposition tank containing an electrodeposition paint and an electrode disposed in the electrodeposition tank, immersing the object to be coated in the electrodeposition paint; a step of adjusting the temperature of the electrodeposition paint to a first temperature by a first temperature adjusting unit; a step of adjusting the temperature of the electrodeposition paint to a second temperature higher than the first temperature by a second temperature adjusting unit; a step of controlling, by a control device, the opening and closing of a plurality of valves provided in a plurality of pipes connecting the first and second temperature adjustment units and the electrodeposition tank based on the specifications of the object to be coated; a step of spraying the electrodeposition paint, the temperature of which has been adjusted to the first and second temperatures, into the electrodeposition tank from a plurality of nozzles provided corresponding to each of the plurality of valves, The object to be coated has a bag structure surrounded by a side surface and a top surface, and the object to be coated has a first portion that is inside the bag structure and a second portion that is outside the bag structure, the electrode is disposed on the outside of the bag structure of the object to be coated, An electrodeposition coating method using an electrodeposition coating device, in which the nozzle selected to spray the electrodeposition paint at the second temperature is positioned closer to the first part than the nozzle selected to spray the electrodeposition paint at the first temperature. (Appendix 10) 10. An electrodeposition coating method according to claim 8 or 9, comprising the steps of: after the step of immersing the object to be coated in the electrodeposition paint, spraying the electrodeposition paint heated to the second temperature toward the first portion; and, after the object to be coated is removed from the tank, stopping the spraying of the electrodeposition paint heated to the second temperature. (Appendix 11) a step of inputting specifications of the object to be coated into the control device before the step of immersing the object to be coated in the electrodeposition paint; 11. The electrodeposition coating method according to any one of claims 8 to 10, wherein after the object to be coated is placed in the tank, the electrodeposition paint heated to the second temperature is sprayed from a plurality of nozzles selected according to the specifications of the object to be coated. (Appendix 12) An electrodeposition coating method according to any one of claims 8 to 11, wherein the control device controls the selection of the plurality of nozzles from which the electrodeposition paint heated to the second temperature is sprayed in accordance with the movement of the object to be coated inside the electrodeposition tank. (Appendix 13) a step of adjusting the temperature of the electrodeposition paint to a third temperature lower than the first temperature by a third temperature adjusting unit; The electrodeposition coating method according to any one of appendices 8 to 12, wherein the electrodeposition paint cooled to the third temperature is sprayed onto the second portion from another nozzle provided opposite the electrode through a fourth pipe connected to the third temperature adjustment unit and a fifth pipe branching from the fourth pipe and connected to the electrodeposition tank. (Appendix 14) 14. The electrodeposition coating method according to claim 13, wherein the electrodeposition paint cooled to the third temperature is sprayed toward the second portion, and after the object to be coated is removed from the tank, the spraying of the electrodeposition paint cooled to the third temperature is stopped. (Appendix 15) 15. An electrodeposition coating method according to claim 13 or 14, wherein specifications of the object to be coated are input into the control device, and after the object to be coated is placed in the tank, the electrodeposition paint cooled to the third temperature is sprayed from another nozzle selected in accordance with the specifications of the object to be coated.

[0045] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not exemplified are conceivable within the scope of the technology disclosed in this specification, including, for example, cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of another embodiment. [Explanation of symbols]

[0046] 1 Electrodeposition paint, 2 Electrodeposition tank, 3 Workpiece, 4 Electrode, 5 Power supply, 6a, 6b, 6c Heat exchanger, 7, 7a, 7b Nozzle, 7d Another nozzle, 8a Temperature control system for setting the temperature under standard processing conditions, 8b Temperature control system for setting the temperature about 10°C higher than the standard processing conditions, 8c Temperature control system for setting the temperature about 10°C lower than the standard processing conditions, 9 Valve, 9a First valve, 9b Second valve, 9c Third valve, 9d Fourth valve, 10 Control device, 11a Hanger, 11b Rail, 12 Conveyor device, 13 Overflow tank, 14 Suction port, 15 Pump, 16 Filter, 17 Third pipe, 17a First pipe, 17b Second pipe, 17c Fourth pipe, 17d Fifth pipe, 18 Heated paint, 19 Standard temperature paint, 20 Cooled paint, 100 electrocoating equipment

Claims

1. an electrodeposition tank containing electrodeposition paint; an electrode disposed in the electrodeposition tank; a power supply device that applies a voltage between the electrode and the object to be coated immersed in the electrodeposition paint; a first temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a first temperature; a second temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a second temperature higher than the first temperature; a plurality of pipes connecting the first and second temperature adjustment units and the electrodeposition tank; a control device that controls opening and closing of a plurality of valves provided in a plurality of the pipes based on the specifications of the object to be coated; the electrodeposition paints adjusted to the first and second temperatures are sprayed into the electrodeposition tank from a plurality of nozzles provided corresponding to the plurality of valves, An electrocoating device in which, when the object to be coated has a first portion and a second portion which have different electrical resistances as viewed from the power supply, and the electrical resistance of the first portion is higher than the electrical resistance of the second portion, the nozzle selected to spray the electrocoating paint at the second temperature is positioned closer to the first portion than the nozzle selected to spray the electrocoating paint at the first temperature.

2. an electrodeposition tank containing electrodeposition paint; an electrode disposed in the electrodeposition tank; a power supply device that applies a voltage between the electrode and the object to be coated immersed in the electrodeposition paint; a first temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a first temperature; a second temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a second temperature higher than the first temperature; a plurality of pipes connecting the first and second temperature adjustment units and the electrodeposition tank; a control device that controls opening and closing of a plurality of valves provided in a plurality of the pipes based on the specifications of the object to be coated; the electrodeposition paints adjusted to the first and second temperatures are sprayed into the electrodeposition tank from a plurality of nozzles provided corresponding to the plurality of valves, The object to be coated has a bag structure surrounded on the side and top, and the object to be coated has a first portion which is inside the bag structure and a second portion which is outside the bag structure, the electrode is disposed on the outside of the bag structure of the object to be coated, An electrocoating apparatus in which the nozzle selected to spray the electrocoating paint at the second temperature is positioned closer to the first portion than the nozzle selected to spray the electrocoating paint at the first temperature.

3. an overflow tank disposed adjacent to the electrodeposition tank; 3. The electrodeposition coating apparatus according to claim 1, wherein the electrodeposition paint is supplied to the first temperature adjusting section and the second temperature adjusting section through suction ports provided in the overflow tank.

4. 3. An electrodeposition coating apparatus according to claim 1, wherein the object to be coated is immersed in the electrodeposition tank while being suspended by a hanger from a conveying device provided above the electrodeposition tank.

5. the plurality of pipes include first and second pipes connected to the first and second temperature adjustment units, respectively, and a third pipe branched from the first and second pipes and connected to the electrodeposition tank; 3. An electrocoating apparatus as described in claim 1 or claim 2, wherein the plurality of nozzles are shared by the electrocoating paint adjusted to the first temperature by the first temperature adjustment unit and the electrocoating paint adjusted to the second temperature by the second temperature adjustment unit.

6. a third temperature adjusting unit that adjusts the temperature of the electrodeposition paint to a third temperature that is lower than the first temperature; a fourth pipe connected to the third temperature adjustment unit; a fifth pipe branched from the fourth pipe and connected to the electrodeposition tank; the control device controls opening and closing of a third valve provided in the fourth pipe and a fourth valve provided in the fifth pipe based on specifications of the object to be coated; 3. An electrocoating apparatus as described in claim 1 or claim 2, wherein the electrocoating paint whose temperature has been adjusted to the third temperature is sprayed into the electrocoating tank from another nozzle provided corresponding to the fourth valve.

7. 7. An electrodeposition coating apparatus according to claim 6, wherein the other nozzle is provided opposite to the electrode.

8. An electrodeposition coating method for forming a coating film by applying a voltage from a power supply between an object to be coated immersed in an electrodeposition tank containing an electrodeposition paint and an electrode disposed in the electrodeposition tank, immersing the object to be coated in the electrodeposition paint; a step of adjusting the temperature of the electrodeposition paint to a first temperature by a first temperature adjusting unit; a step of adjusting the temperature of the electrodeposition paint to a second temperature higher than the first temperature by a second temperature adjusting unit; a step of controlling, by a control device, the opening and closing of a plurality of valves provided in a plurality of pipes connecting the first and second temperature adjustment units and the electrodeposition tank based on the specifications of the object to be coated; a step of spraying the electrodeposition paint, the temperature of which has been adjusted to the first and second temperatures, into the electrodeposition tank from a plurality of nozzles provided corresponding to each of the plurality of valves, an electrodeposition coating method comprising: when the object to be coated has a first portion and a second portion which have different electrical resistances as viewed from the power supply device, and the electrical resistance of the first portion is higher than the electrical resistance of the second portion, bringing the nozzle selected to spray the electrodeposition paint at the second temperature closer to the first portion than the nozzle selected to spray the electrodeposition paint at the first temperature.

9. An electrodeposition coating method for forming a coating film by applying a voltage from a power supply between an object to be coated immersed in an electrodeposition tank containing an electrodeposition paint and an electrode disposed in the electrodeposition tank, immersing the object to be coated in the electrodeposition paint; a step of adjusting the temperature of the electrodeposition paint to a first temperature by a first temperature adjusting unit; a step of adjusting the temperature of the electrodeposition paint to a second temperature higher than the first temperature by a second temperature adjusting unit; a step of controlling, by a control device, the opening and closing of a plurality of valves provided in a plurality of pipes connecting the first and second temperature adjustment units and the electrodeposition tank based on the specifications of the object to be coated; a step of spraying the electrodeposition paint, the temperature of which has been adjusted to the first and second temperatures, into the electrodeposition tank from a plurality of nozzles provided corresponding to each of the plurality of valves, The object to be coated has a bag structure surrounded on the side and top, and the object to be coated has a first portion which is inside the bag structure and a second portion which is outside the bag structure, the electrode is disposed on the outside of the bag structure of the object to be coated, An electrodeposition coating method using an electrodeposition coating device, in which the nozzle selected to spray the electrodeposition paint at the second temperature is positioned closer to the first portion than the nozzle selected to spray the electrodeposition paint at the first temperature.

10. 10. An electrodeposition coating method as described in claim 8 or claim 9, further comprising the steps of: after the step of immersing the object to be coated in the electrodeposition paint, spraying the electrodeposition paint heated to the second temperature toward the first portion; and, after the object to be coated is removed from the tank, stopping the spraying of the electrodeposition paint heated to the second temperature.

11. a step of inputting specifications of the object to be coated into the control device before the step of immersing the object to be coated in the electrodeposition paint; 10. An electrodeposition coating method according to claim 8 or claim 9, wherein after the object to be coated is placed in the tank, the electrodeposition paint heated to the second temperature is sprayed from a plurality of nozzles selected according to the specifications of the object to be coated.

12. An electrocoating method as described in claim 8 or claim 9, wherein the control device controls the selection of the plurality of nozzles from which the electrocoating paint heated to the second temperature is sprayed in accordance with the movement of the object to be coated inside the electrocoating tank.

13. and a step of adjusting the temperature of the electrodeposition paint to a third temperature lower than the first temperature by a third temperature adjusting unit; 10. An electrocoating method as described in claim 8 or claim 9, wherein the electrocoating paint cooled to the third temperature is sprayed onto the second portion from another nozzle provided opposite the electrode through a fourth pipe connected to the third temperature adjustment unit and a fifth pipe branching off from the fourth pipe and connected to the electrocoating tank.

14. 14. An electrodeposition coating method according to claim 13, wherein the electrodeposition paint cooled to the third temperature is sprayed toward the second portion, and after the object to be coated is removed from the tank, the spraying of the electrodeposition paint cooled to the third temperature is stopped.

15. 14. An electrocoating method as described in claim 13, wherein specifications of the object to be coated are input into the control device, and after the object to be coated is placed in the tank, the electrocoating paint cooled to the third temperature is sprayed from another nozzle selected in accordance with the specifications of the object to be coated.

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