JP2012180585A - Electrodeposition coating method, method for manufacturing coated part, and workpiece conveyance device for electrodeposition coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an electrodeposition coating method capable of suppressing generation of seeds and surely removing bubbles attached to a workpiece; a method for manufacturing a coated part; and a workpiece conveyance device for electrodeposition coating.SOLUTION: In the workpiece conveyance device 55, workpieces W are intermittently progressed in order at a constant conveyance pitch while the workpieces W are received/delivered between a placing part 40 and workpiece lift parts 51, 52, the placing part 40 retaining the workpieces W while the workpieces W are immersed in an electrodeposition paint liquid. Each of the workpiece lift parts 51, 52 includes two types of an immersion maintaining workpiece lift part 51 and a drawing workpiece lift part 52, the immersion maintaining workpiece lift part 51 conveying the workpieces W while the workpieces W are immersed in the electrodeposition paint liquid as a progress of a conveyance base member 50, and the drawing workpiece lift part 52 conveying the workpieces W while the workpieces W are taken out from the electrodeposition paint liquid as the progress of the conveyance base member 50. The immersion maintaining workpiece lift parts 51 are arranged so that a number of the immersion maintaining workpiece lift parts 51 disposed continuously is larger on the downstream side than on the upstream side in the workpiece conveyance direction.

Description

  The present invention relates to an electrodeposition coating method, a method for manufacturing a coated part, and a workpiece conveying apparatus for electrodeposition coating.

  In general, in electrodeposition coating, hydrogen gas is generated by electrolysis of water during the process of forming an electrodeposition coating. If bubbles of this hydrogen gas or other gas enter the electrodeposition coating, they may cause a so-called “gas pinhole”, and therefore it is essential to remove the bubbles attached to the workpiece. On the other hand, as a conventional electrodeposition coating method, the electrodeposition treatment liquid was allowed to flow in one direction inside the electrodeposition treatment tank, and bubbles attached to the workpiece were removed by the flow of the electrodeposition treatment liquid. Those are known (for example, see Patent Document 1).

JP 2001-20094 (paragraph [0005], FIG. 1)

  However, although the conventional electrodeposition coating method described above can remove the bubbles in the portion opposite to the flow direction of the electrodeposition treatment liquid, it is difficult to remove the bubbles on the back side. Further, when the bubbles are removed by increasing the flow rate of the processing liquid, impurities rise and cause a so-called “poor” coating failure.

  The present invention has been made in view of the above circumstances, and is an electrodeposition coating method capable of suppressing the generation of blisters and reliably removing bubbles adhering to a workpiece, a method for manufacturing a coated component, and electrodeposition The purpose is to provide a workpiece transfer device for painting.

  The electrodeposition coating method according to the first aspect of the invention, which has been made to achieve the above object, removes the bubbles adhering to the workpiece by removing the workpiece from the electrodeposition treatment solution a plurality of times during the electrodeposition coating process. An electrodeposition coating method for performing electrodeposition coating, characterized in that the continuous immersion time in which the workpiece is immersed without being taken out from the electrodeposition treatment liquid is increased with the passage of time from the start of the electrodeposition coating process. .

  An electrodeposition coating method according to a second aspect of the present invention is a workpiece electrodeposition coating method in which a plurality of workpieces are intermittently fed in the workpiece transfer direction at a fixed transfer pitch while performing an electrodeposition process, and the upper end of each workpiece. A pair of side projections projecting from both sides to be placed on both sides of the workpiece conveyance area, and a workpiece conveyance direction for holding the workpiece immersed in the electrodeposition treatment liquid A plurality of work lift portions arranged at the same interval as the transport pitch are fixed to a common transport base member, and all the work lift portions are lifted and come into contact with a part of each work. After that, the first operation for lifting the workpiece, the second operation for all workpiece lift sections to move forward and transport each workpiece, and all the workpiece lift sections descend to place each workpiece on the placement section. After the third movement away from a part of the workpiece And a fourth operation in which all the work lift parts move backward and move to a lower position of a part of the next work. In the work electrodeposition coating method to be performed, a plurality of work lift parts are arranged at positions that come into contact with a part of the work at a relatively initial stage of the first operation in order to transport the work in a state of being extracted from the electrodeposition treatment liquid. The workpiece lift unit for extracting the workpiece from the electrodeposition treatment liquid in the first operation, and the workpiece at a relatively final stage of the first operation for transporting the workpiece while being immersed in the electrodeposition treatment liquid. Two types of work lifts, which are arranged at a position where they come into contact with the part, and a work lifting part for maintaining immersion that separates the side protrusion upward from the mounting part without removing the work from the electrodeposition treatment liquid in the first operation Have a department In the middle of the electrodeposition coating process, it is possible to remove the workpiece from the electrodeposition treatment liquid and remove bubbles adhering to the workpiece. It is characterized in that the continuous soaking time that the work is immersed without taking it out from the electrodeposition treatment liquid becomes longer with the passage of time from the start of the electrodeposition coating process by arranging it so that the number of lines is increased. Have

  The invention of claim 3 is characterized in that in the electrodeposition coating method according to claim 1 or 2, vibration is imparted to the workpiece during the continuous immersion time.

  The invention of claim 4 is characterized in that, in the electrodeposition coating method according to claim 3, the frequency or amplitude of vibration applied to the workpiece is reduced with the passage of time from the start of the electrodeposition coating process.

  According to a fifth aspect of the present invention, there is provided a method for manufacturing a coated part, wherein the electrodeposition coating method according to any one of the first to fourth aspects is used to manufacture a part having a surface electrodeposited with a paint. Has characteristics.

  According to a sixth aspect of the present invention, there is provided a workpiece transfer apparatus for electrodeposition coating, in which a plurality of workpieces are intermittently fed in the workpiece transfer direction at a fixed transfer pitch while performing an electrodeposition process. A pair of side projections projecting in the direction is placed on both sides of the workpiece conveyance area for holding the workpiece immersed in the electrodeposition treatment liquid, and the conveyance pitch in the workpiece conveyance direction. A plurality of work lift parts arranged at the same interval are fixed to a common transport base member, and all work lift parts are lifted and contacted with a part of each work, and then the work lift part is lifted. Part of the workpiece after one operation, the second operation in which all the work lift units move forward and transport each work, and all the work lift units descend and place each work on the placement unit The third movement away from the Electrodeposition coating that causes the transport base member to perform a cycle operation consisting of ascending, advancing, descending, and retreating so that the lift part performs the fourth operation of retreating and moving to a lower position of a part of the next workpiece. In the work transfer device for work, as a plurality of work lift units, arranged to be in contact with a part of the work at a relatively initial stage of the first operation in order to transport the work in a state of being extracted from the electrodeposition treatment liquid, A workpiece lift unit for extracting the workpiece from the electrodeposition treatment liquid in the first operation, and a part of the workpiece at a relatively final stage of the first operation for transporting the workpiece immersed in the electrodeposition treatment liquid. Provided with two types of work lift parts that are arranged in contact with each other and a work lifting part for maintaining immersion that separates the side protrusions upward from the placement part without removing the work from the electrodeposition treatment liquid in the first operation. In the workpiece transfer direction Towards the Chi downstream has characterized in that the work lifting unit for dipping maintained upstream side is arranged such that the number of continuously arranged increases.

  A seventh aspect of the invention is characterized in that in the electrodeposition coating work transfer apparatus according to the sixth aspect of the invention, a vibration source for applying vibration to the work by vibrating the mounting portion is provided.

  An eighth aspect of the present invention is the electrodeposition coating work transfer device according to the seventh aspect, wherein the mounting portion is divided into a plurality of parts in the work transfer direction, and the vibration received by the mounting portion downstream in the work transfer direction. It has a feature in that a plurality of vibration sources are provided so that the frequency or amplitude is smaller than the frequency or amplitude of vibration received by the upstream mounting portion.

[Inventions of Claims 1, 2, 5, and 6]
In general, the hydrogen gas generated during the formation of the electrodeposition coating is generated more as the beginning of the electrodeposition coating process, and gradually decreases toward the end of the electrodeposition coating process. On the other hand, according to the invention of claim 1, the length of the continuous immersion period is increased with the passage of time from the start of the electrodeposition coating process. That is, in the early stage of the electrodeposition coating process in which a relatively large number of bubbles can be generated, the continuous immersion period was relatively shortened, and the continuous immersion period was lengthened toward the final stage where the generation of bubbles was reduced.

  Thus, according to the inventions of claims 1 and 5, the work is taken out of the electrodeposition treatment liquid during the electrodeposition coating process, and the entire surface of the work or the electrodeposition coating is exposed to the atmosphere. Regardless of the part of the workpiece, the attached bubbles can be reliably removed (defoamed). Thereby, it is possible to manufacture a high-quality painted part that prevents the irregularity and the gas pinhole. Moreover, since the workpiece is taken out from the electrodeposition treatment liquid at a timing according to the amount of bubbles generated, it is possible to prevent the time for taking out from the electrodeposition treatment liquid with respect to the amount of bubbles attached is prevented and efficient. Air bubbles can be removed.

  Here, in the electrodeposition coating process, only the insertion / extraction of the workpiece with respect to the electrodeposition treatment liquid may be repeated, or a plurality of workpieces are conveyed at a constant conveyance pitch as in the inventions of claims 2 and 6. You may make it repeat insertion / extraction with respect to an electrodeposition process liquid, feeding it forward in the direction intermittently.

  The work taken out from the electrodeposition treatment liquid may be left as it is, or the work taken out from the electrodeposition treatment liquid may be vibrated, or air bubbles may be applied to remove bubbles.

[Inventions of Claims 3 and 7]
According to the third and seventh aspects of the present invention, the bubbles adhering to the workpiece can be removed even in a state where the bubbles are immersed in the electrodeposition treatment liquid.

[Inventions of Claims 4 and 8]
According to invention of Claim 4 and 8, a bubble can be removed by the vibration according to the generation amount (bubble adhesion amount) of a bubble.

Front sectional view of an electrodeposition coating apparatus in a state in which a work lift for maintaining immersion of the electrodeposition coating work transfer device according to the first embodiment of the present invention is lowered. Front sectional view of the electrodeposition coating device with the work lift for extraction lowered Front cross-sectional view of the electrodeposition coating device with the work lift for dipping maintenance raised Front sectional view of the electrodeposition coating device with the work lift for extraction raised Perspective view of workpiece transfer device for electrodeposition coating and workpiece Side cross-sectional view of the electrodeposition coating device with the work lift part retracted Side cross-sectional view of the electrodeposition coating device with the workpiece lift raised Side cross-sectional view of the electrodeposition coating device with the work lift part advanced Side sectional view of the electrodeposition coating device with the work lift part lowered Side sectional view of the electrodeposition coating apparatus according to the second embodiment Side sectional view of an electrodeposition coating apparatus according to the third embodiment Conceptual diagram of a workpiece transfer device for electrodeposition coating according to a modified example

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 6, the electrodeposition coating apparatus 10 includes an electrodeposition bath 11 extending in the horizontal direction, and an electrodeposition treatment liquid is stored in the electrodeposition bath 11. The workpiece W, which is a part to be coated, is inserted in and removed from the electrodeposition treatment liquid by the electrodeposition coating work transfer device 55 (hereinafter referred to as “work transfer device 55”) according to the present invention, and the longitudinal direction of the electrodeposition bath 11 Are intermittently transported at a constant transport pitch from one end to the other end (from left to right in FIG. 6). And while being immersed in an electrodeposition processing liquid, electricity supply is performed between the electrode (not shown) arrange | positioned in an electrodeposition processing liquid and the workpiece | work W, and the electrodeposition coating material is applied to the surface of the workpiece | work W A film is formed. Further, the electrodeposition treatment liquid is circulated by the pump 15, and in the electrodeposition bath 11, for example, the flow is opposite to the direction in which the workpiece W is conveyed (opposite flow). In the following description, “one end side in the longitudinal direction of the electrodeposition bath 11” is referred to as “upstream side in the workpiece conveyance direction”, and “the other end side in the longitudinal direction of the electrodeposition bath 11” is referred to as “downstream side in the workpiece conveyance direction”. "

  FIG. 5 shows an electromagnetic coil for a motor as an example of the workpiece W. As shown in the figure, the electromagnetic coil is wound so that a copper wire having a flat cross section is square when viewed from the winding axis direction, and a pair of terminal portions Wb and Wb are formed in a rectangular shape of the winding portion Wa. It has a structure that protrudes linearly in the same direction from one side. And the whole winding part Wa in this electromagnetic coil is immersed in an electrodeposition process liquid, and coating (for example, insulation coating) is performed. In the present embodiment, only the electromagnetic coil is illustrated as the workpiece W, but the workpiece W is not limited to the electromagnetic coil. For example, a body or a building material of an automobile or other parts not illustrated here may be used as the workpiece W.

  As shown in FIG. 5, the workpiece W is held by a workpiece holder 30. The work holder 30 includes a holder main body 31 and a pair of side protrusions 32 and 32 that protrude laterally from the holder main body 31. The holder main body 31 is formed with a pair of holding holes 31A, 31A penetratingly formed so that the holder main body 31 can be prevented from coming off while the pair of terminal portions Wb, Wb of the workpiece W are inserted into the holding holes 31A, 31A. . Moreover, the side protrusions 32 and 32 protrude from the holder main body 31 in directions opposite to each other, and have, for example, a quadrangular prism shape.

  As shown in FIG. 6, a placement unit 40 is provided above the electrodeposition bathtub 11. The mounting portion 40 is composed of a pair of band-like members 41 and 41 extending in parallel with each other along both sides of the workpiece transfer area by the workpiece transfer device 55 (see FIG. 5). On the upper surface, a plurality of mounting grooves 42 and 42 are formed in a recessed manner with an interval of a constant conveyance pitch P1 in the longitudinal direction. The mounting grooves 42, 42 are V-shaped according to the shape of the side protrusions 32, 32, and the side protrusions 32, 32 can be fitted into the mounting grooves 42, 42. In addition, the workpiece | work W mounted in the mounting part 40 is stabilized by making the side protrusions 32 and 32 and the mounting grooves 42 and 42 into the said shape.

  The work transfer device 55 includes a transfer base member 50 that performs a cycle operation, which will be described later, with the power of a drive source (not shown), and a plurality of work lift portions 51 and 52 fixed to the transfer base member 50.

  The conveyance base member 50 is disposed above the placement unit 40 and has a vertically long structure extending in the longitudinal direction of the electrodeposition bathtub 11, that is, in the workpiece conveyance direction. The conveyance base member 50 moves vertically upward by a predetermined lifting stroke S1 toward the upper side of the electrodeposition bathtub 11, and moves forward by a fixed conveyance pitch P1 toward the downstream side in the workpiece conveyance direction. ”,“ Descent ”that moves vertically toward the electrodeposition bathtub 11 by a predetermined lifting stroke S1 and“ Reverse ”that moves horizontally by a certain conveying pitch P1 toward the upstream side in the workpiece conveying direction. One cycle operation is performed, and this one cycle operation is repeated (see FIGS. 6 to 9).

  The plurality of work lift portions 51 and 52 are arranged in a line at intervals of a certain conveyance pitch P1 in the workpiece conveyance direction, and are integrated with the conveyance base member 50 to “rise”, “forward”, Perform “descent” and “backward” cycle operations. The cycle operation of the transport base member 50 and the work lift parts 51 and 52 is performed outside the electrodeposition bath 11, and the transport base 50 and the work lift parts 51 and 52 are not immersed in the electrodeposition treatment liquid (FIG. 1). To FIG. 4).

  Each work lift part 51, 52 is configured by a pair of hanger arms 53, 53 facing each other in the width direction of the electrodeposition bathtub 11. The pair of hanger arms 53, 53 has a hook shape that hangs down from the conveyance base member 50 and has a lower end bent inward at right angles, and on the upper surface of the hook portions 53F, 53F, V-shaped protrusion receiving grooves 54 are respectively formed in accordance with the shapes of the protrusions 32 and 32 (see FIG. 5). The side protrusions 32 and 32 can be engaged with the protrusion receiving grooves 54 and 54, respectively. Since the side protrusions 32 and 32 and the protrusion receiving grooves 54 and 54 have the above shapes, the workpiece W is stabilized when the workpiece W is lifted by the workpiece lift portions 51 and 52 as described later.

  The plurality of work lift parts 51 and 52 are composed of two types, that is, a work lift part 51 for maintaining immersion and a work lift part 52 for extracting, and maintaining the immersion as compared with the work lift part 52 for extracting. The work lift portion 51 for use protrudes downward (on the electrodeposition bathtub 11 side). That is, in the work lift part 51 for maintaining immersion, the hook parts 53F and 53F are positioned below the work lift part 52 for extraction. This is the only difference between the work lifting parts 51 and 52 for maintaining immersion and for extracting.

  The arrangement of the work lift parts 51 and 52 is as follows. That is, on the upstream side (the left side in FIG. 6) in the workpiece conveyance direction, the work lifting portions 51 and 52 for immersion maintenance and extraction are alternately arranged one by one. On the other hand, a plurality of (for example, two) work lift portions 51 for maintaining immersion are continuously arranged on the downstream side in the workpiece conveyance direction (the right side in FIG. 6). The configuration of the present embodiment is as described above.

  Next, the operation of this embodiment will be described. When performing electrodeposition coating on the workpiece W, the workpiece W that has been subjected to a pre-process such as a degreasing process is placed at the upstream end position in the workpiece conveyance direction in the placement portion 40 via the workpiece holder 30. Immerse in the electrodeposition solution. When the workpiece transfer device 55 is activated, the workpiece W placed on the placement unit 40 is intermittently transferred by a fixed transfer pitch P1 toward the downstream side in the workpiece transfer direction. In the conveyance process, electricity is applied between an electrode (not shown) in the electrodeposition bath 11 and the work W, and an electrodeposition film is generated on the surface of the work W. The workpiece | work W which reached | attained the downstream end of a workpiece | work conveyance direction is pulled up from the electrodeposition bathtub 11, and is conveyed by a post process (for example, a washing process, a baking process, etc.).

  By the way, in the formation process of an electrodeposition film, hydrogen gas is generated by electrolysis of water, and it can adhere to the surface of the workpiece W or the electrodeposition film as bubbles. In order to remove the bubbles, the workpiece transfer device 55 takes out the workpiece W from the electrodeposition treatment liquid a plurality of times during the electrodeposition coating process (while the workpiece W is being transferred).

  Further, the hydrogen gas generated during the formation of the electrodeposition coating is generated more in the early stage of the electrodeposition coating process, and gradually decreases toward the end of the electrodeposition coating process. Therefore, the workpiece transfer device 55 according to the present embodiment operates with long and short changes in a period during which the workpiece W is immersed without being taken out from the electrodeposition treatment liquid (hereinafter referred to as “continuous immersion period”). Specifically, the early stage of the electrodeposition coating process operates so as to shorten the continuous soaking period and lengthen the continuous soaking period at the end.

  Specifically, as shown in FIG. 6, when the conveyance base member 50 of the workpiece conveyance device 55 is disposed at the rear end position of the conveyance pitch and at the lower end position of the lifting stroke, all the workpieces W are workpiece holders. It is mounted on the mounting part 40 via 30 and is maintained in a state immersed in the electrodeposition treatment liquid (see FIGS. 1 and 2).

  From this state, when the transport base member 50 is “raised” by a predetermined lift stroke S1, the hook portions 53F and 53F of the work lift portions 51 and 52 and the placement portion 40 pass each other during the raising process. In addition, each of the workpiece lifts 51 and 52 receives the workpiece W from the placement unit 40 and all the workpieces W are lifted from the placement unit 40 (corresponding to the “first operation” of the present invention). Specifically, at a relatively early stage of the ascending process, the extraction work lift 52 receives the work W from the mounting part 40, and at a relatively final stage of the ascending process, the work lifting part 51 for maintaining immersion is placed. The workpiece W is received from the placement unit 40.

  Then, as shown in FIG. 7, when the transport base member 50 reaches the upper end position of the lifting / lowering stroke, the workpiece W (winding portion Wa) lifted by the workpiece lifting portion 51 for maintaining immersion is used as the electrodeposition treatment liquid. While being immersed, the workpiece W lifted by the workpiece lifting unit 52 for extraction is completely extracted from the electrodeposition treatment liquid (see FIGS. 3 and 4).

  Subsequently, the conveyance base member 50 “advances” by a certain conveyance pitch P1 in the workpiece conveyance direction. Then, as shown in FIG. 8, all the workpieces W lifted to the workpiece lifting portions 51 and 52 are also advanced by a certain conveying pitch P1 (corresponding to the “second operation” of the present invention). To do). At this time, the work W lifted by the work lifting part 51 for maintaining immersion advances while being immersed in the electrodeposition treatment liquid, and the work W lifted by the work lifting part 52 for extraction is subjected to the electrodeposition process. Advances while being removed from the liquid. And while the workpiece | work W is taken out from an electrodeposition process liquid and is touching air | atmosphere, the bubble adhering to the surface of the workpiece | work W or an electrodeposition film | membrane disappears naturally.

  When the transport base member 50 reaches the front end position of the transport pitch, the transport base member 50 then “lowers” by a predetermined lift stroke S1. In the descending process, the hook portions 53F, 53F of the work lift portions 51, 52 and the placement portion 40 pass each other, and the workpiece W is transferred from the work lift portions 51, 52 to the placement portion 40 at that time. (This corresponds to the “third operation” of the present invention). Specifically, at a relatively initial stage of the lowering process, the work W is transferred from the work lifting section 51 for maintaining immersion to the placement section 40, and the work lifting section for extraction at a relatively final stage of the lowering process. The workpiece W is delivered from 52 to the placement unit 40. As shown in FIG. 9, when the transport base member 50 reaches the lower end position of the lifting / lowering stroke, all the workpieces W are held in a state of being immersed in the electrodeposition treatment liquid. Thereafter, when the transport base member 50 “retreats” by a certain transport pitch P1 in the work transport direction, the hook parts 53F, 53F of all the work lift parts 51, 52 are moved to the next work W (specifically, the work holder 30 side protrusions 32 and 32) (corresponding to the “fourth operation” of the present invention), and thereafter, “up”, “forward”, “down”, and “reverse” operations are repeated. Thus, the plurality of workpieces W are intermittently conveyed by a certain conveyance pitch P1.

  Here, in the work transfer device 55, work lift parts 51 and 52 for immersion maintenance and extraction are alternately arranged one by one on the upstream side in the work transfer direction, while on the downstream side in the work transfer direction. In addition, a plurality of (for example, two) work lift parts 51 for maintaining immersion are arranged to be continuous. As described above, since the workpiece W is taken out from the electrodeposition treatment liquid only when the workpiece W is lifted by the workpiece lifting portion 52 for extraction, in the early stage of the electrodeposition coating process, the continuation of the workpiece W is performed. The immersion period is relatively short, and the continuous immersion period of the workpiece W is relatively long at the end of the electrodeposition coating process.

  In other words, the beginning of the electrodeposition coating process, in which a relatively large number of bubbles can be generated, has a short time interval for taking out the workpiece W from the electrodeposition treatment liquid, and the last stage of the electrodeposition coating process in which the generation of bubbles is reduced is electrodeposition. The time interval for taking out the workpiece W from the processing liquid is relatively long.

  As described above, according to the present embodiment, the workpiece W is taken out from the electrodeposition treatment liquid during the electrodeposition coating process, and the entire surface of the workpiece W or the electrodeposition coating is exposed to the atmosphere. Regardless of the region, air bubbles can be reliably removed (defoamed). As a result, a high-quality painted part (in this embodiment, an electromagnetic coil) can be manufactured in which flaws and gas pinholes are prevented. In addition, since the workpiece W is taken out from the electrodeposition treatment liquid at a timing according to the amount of bubbles generated, it is possible to prevent the time for taking out the electrodeposition treatment liquid from the amount of bubbles attached from being excessive and insufficient. Thus, bubbles can be removed (defoamed).

[Second Embodiment]
This embodiment is shown in FIG. As shown in the figure, a vibration source 60 that generates, for example, ultrasonic vibration is connected to the mounting unit 40, and the mounting unit 40 (band-like members 41, 41) is vibrated to thereby mount the mounting unit 40. The work W placed on the portion 40 is vibrated. That is, it is possible to separate and remove bubbles adhering to the workpiece W by vibrating the workpiece W immersed in the electrodeposition treatment liquid. Note that the vibration of the vibration source 60 may be input at any position on the upstream side, the downstream side, or the intermediate position in the workpiece conveyance direction in the placement unit 40. Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and redundant description is omitted. According to the present embodiment, the same effect as that of the first embodiment can be obtained, and air bubbles can be removed while the workpiece W is immersed in the electrodeposition treatment liquid. Generation of gas pinholes) can be prevented more reliably.

[Third Embodiment]
This embodiment is shown in FIG. As shown in the figure, the mounting unit 40 is divided into a plurality of parts in the workpiece conveyance direction, and the vibration sources 60 and 60 are provided for the mounting units 40 and 40, respectively. Different from the second embodiment. In the present embodiment, the frequency or amplitude of vibration received by the placement unit 40 on the downstream side in the workpiece conveyance direction is configured to be smaller than the frequency or amplitude of vibration received by the placement unit 40 on the upstream side, The bubbles can be separated and removed with the strength of vibration corresponding to the amount of bubbles generated (the amount of bubbles attached). Since other configurations are the same as those of the second embodiment, a duplicate description is omitted. Also according to the present embodiment, the same effects as those of the second embodiment can be obtained.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) In the first to third embodiments, the work W is taken out from the electrodeposition treatment liquid and the bubbles adhering to the work W are naturally eliminated in the atmosphere. For example, the viscosity of the electrodeposition treatment liquid is high. In such a case, vibrations, wind, and liquid may be applied to the workpiece W taken out from the electrodeposition treatment liquid to forcibly remove (defoam) bubbles. What is necessary is just to vibrate the work lift parts 51 and 52 when providing a vibration. Moreover, when applying a liquid, it is preferable to use the electrodeposition processing liquid of the same component as the inside of the electrodeposition bathtub 11 (for example, pumping up and using the electrodeposition processing liquid in the electrodeposition bathtub 11).

  (2) In the first to third embodiments, the workpiece transfer device 55 is configured to repeat insertion and removal with respect to the electrodeposition treatment liquid while transferring the workpiece W in order, but the workpiece W is not transferred without being transferred. It is good also as a structure which repeats only insertion / extraction with respect to a process liquid.

  (3) The number and arrangement of the work lift portions 51 and 52 for maintaining immersion and for extracting are not limited to those exemplified in the first to third embodiments, and do not depart from the gist of the present invention. The number and arrangement may be changed with.

  (4) The workpiece transfer device does not have to repeat the operation of one cycle of forward movement, lowering, backward movement, and upward as in the first to third embodiments. For example, as shown in FIG. A structure in which a plurality of work lift portions 56, 56 capable of suspending and holding the workpiece W move up and down by the up and down of the guide rail 57 in the process of moving from one end of the electrodeposition bath 11 to the other end on the guide rail 57 It is good.

  (5) In the second embodiment, the vibration of the vibration source 60 is input to the upstream end of the placement unit 40 in the workpiece conveyance direction, and as the vibration is attenuated, the vibration is attenuated toward the downstream side in the workpiece conveyance direction. It is good also as a structure where the vibration which the workpiece | work W receives becomes gentle.

  (6) In the second and third embodiments, the workpiece W is vibrated. However, a vibration source is arranged in the electrodeposition treatment liquid to vibrate the electrodeposition treatment liquid (for example, ultrasonic vibration). Thus, the bubbles may be removed.

  (7) In the first to third embodiments, the workpiece W is held by the workpiece holder 30 in order to allow the workpiece W to be exchanged between the workpiece lift portions 51 and 52 and the placement portion 40. When the workpiece W itself has a portion corresponding to the pair of side protrusions 32, 32 in the workpiece holder 30, the workpiece holder 30 is unnecessary.

  (8) In the first embodiment, the placement unit 40 is provided separately from the electrodeposition bath 11, but the placement unit may be integrated with the electrodeposition bath 11. That is, it is good also considering the upper end part of the width direction of the electrodeposition bathtub 11 as a mounting part.

DESCRIPTION OF SYMBOLS 10 Electrodeposition coating apparatus 11 Electrodeposition bath 30 Work holder 32 Side protrusion 40 Placement part 50 Conveyance base member 51 Work lift part for immersion maintenance 52 Work lift part for extraction 55 Work conveyance part for electrodeposition coating 60 Vibration Source W Work

Claims (8)

An electrodeposition coating method in which electrodeposition coating is performed while taking out a work piece from an electrodeposition treatment solution a plurality of times during the electrodeposition coating process and removing bubbles adhering to the work,
An electrodeposition coating method characterized in that a continuous immersion time in which the workpiece is immersed without being removed from the electrodeposition treatment liquid is lengthened with the passage of time from the start of the electrodeposition coating process. A workpiece electrodeposition coating method in which a plurality of workpieces are intermittently fed in the workpiece conveyance direction at a certain conveyance pitch while performing electrodeposition treatment,
A pair of side projections projecting from the upper end of each workpiece to both sides are placed, and a placement portion for holding the workpiece immersed in the electrodeposition treatment liquid is provided on both sides of the workpiece transfer area. And a plurality of work lift portions arranged at the same interval as the conveyance pitch in the workpiece conveyance direction, and fixed to a common conveyance base member.
After all the work lift parts are lifted and come into contact with a part of each work, the first operation to lift the work and all the work lift parts move forward to convey each work. A second operation, a third operation in which all the work lift parts are lowered and each work is placed on the placement part, and then separated from a part of the work, and all the work lift parts are provided. The workpiece electrodeposition coating that causes the transport base member to perform a cycle operation consisting of ascending, advancing, descending, and retreating so as to perform a fourth operation of retreating and moving to a lower position of the next part of the workpiece. In the method
As the plurality of work lift parts, the work lift parts are disposed at positions that come into contact with a part of the work at a relatively initial stage of the first operation in order to transport the work in a state of being extracted from the electrodeposition treatment liquid, In a first operation, the workpiece lift unit for extracting the workpiece from the electrodeposition treatment liquid, and the work in a relatively final stage of the first operation for transporting the workpiece immersed in the electrodeposition treatment liquid. An immersion maintaining work lift that is disposed at a position in contact with a part of the work and separates the side protrusion upward from the placement part without removing the work from the electrodeposition treatment liquid in the first operation. By providing two types of work lift parts with the part, it is possible to remove the air bubbles attached to the work by taking out the work from the electrodeposition treatment liquid during the electrodeposition coating process,
By arranging the number of work lift parts for immersion maintenance to be continuously arranged in the downstream side of the workpiece transfer direction from the upstream side, the workpiece is not taken out from the electrodeposition treatment liquid. The electrodeposition coating method is characterized in that the continuous immersion time immersed in is increased with the passage of time from the start of the electrodeposition coating process.   The electrodeposition coating method according to claim 1 or 2, wherein vibration is applied to the workpiece during the continuous immersion time.   4. The electrodeposition coating method according to claim 3, wherein the frequency or amplitude of vibration applied to the workpiece is reduced as time elapses from the start of the electrodeposition coating process.   A method for producing a coated part, wherein a part having a surface coated with a paint is produced by using the electrodeposition coating method according to any one of claims 1 to 4. In order to intermittently advance a plurality of workpieces in the workpiece conveyance direction at a constant conveyance pitch while performing an electrodeposition process, a pair of side projections projecting from the upper end of each workpiece to both sides are placed. A plurality of workpieces that are provided on both sides of the workpiece conveyance area and are arranged at the same interval as the conveyance pitch in the workpiece conveyance region, and are provided with holding portions for holding the workpiece in a state of being immersed in the electrodeposition treatment liquid. The lift part is fixed to a common transport base member,
After all the work lift parts are lifted and come into contact with a part of each work, the first operation to lift the work and all the work lift parts move forward to convey each work. A second operation, a third operation in which all the work lift parts are lowered and each work is placed on the placement part, and then separated from a part of the work, and all the work lift parts are provided. For the electrodeposition coating that causes the transport base member to perform a cycle operation consisting of ascending, advancing, descending, and retreating so as to perform the fourth operation of retreating and moving to the lower position of the next part of the workpiece. In workpiece transfer equipment,
As the plurality of work lift parts, the work lift parts are disposed at positions that come into contact with a part of the work at a relatively initial stage of the first operation in order to transport the work in a state of being extracted from the electrodeposition treatment liquid, In a first operation, the workpiece lift unit for extracting the workpiece from the electrodeposition treatment liquid, and the work in a relatively final stage of the first operation for transporting the workpiece immersed in the electrodeposition treatment liquid. An immersion maintaining work lift that is disposed at a position in contact with a part of the work and separates the side protrusion upward from the placement part without removing the work from the electrodeposition treatment liquid in the first operation. Two kinds of work lift parts with the part,
The electrodeposition coating work transfer apparatus, wherein the number of the work-lifting parts for maintaining immersion is continuously increased in the downstream side of the work transfer direction from the upstream side.   The work conveying apparatus for electrodeposition coating according to claim 6, further comprising a vibration source that imparts vibration to the work by vibrating the mounting portion.   The placement unit is divided into a plurality of parts in the workpiece conveyance direction, and the frequency or amplitude of vibration received by the previous placement unit on the downstream side in the workpiece conveyance direction is the frequency of vibration received by the upstream placement unit or The work conveying apparatus for electrodeposition coating according to claim 7, wherein a plurality of the vibration sources are provided so as to be smaller than the amplitude.

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