Paint chamber unit and nozzle head for electrostatic atomizing paint machine

Abstract

The present invention is provided with: a plurality of nozzles 5; a paint chamber 4 extending from an outflow port row, in which a plurality of outflow ports respectively connected to the plurality of nozzles 5 are disposed in a row, to an inflow port into which paint flows; and an open / close valve 3 which opens / closes the inflow port, wherein the width of the paint chamber 4 along the outflow port row gradually increases from the inflow port toward the outflow port row.

Description

Technical Field

[0001] The present invention relates to Paint chamber unit for electrostatic atomizing paint machine and a nozzle head for an electrostatic atomization painting machine.

Background Art

[0002] To automate the painting of automobile bodies and the like, painting robots are widely used. As one aspect of a general painting robot, a robot in which a painting nozzle is attached to the tip of an industrial robot is widely used. As such nozzles, those having various structures according to the painting method are used.

[0003] For example, Japanese Unexamined Patent Application Publication No. 2018-8253 (Patent Document 1) discloses an electrostatic spraying device used when performing electrostatic painting. The electrostatic spraying device of Patent Document 1 includes a nozzle head in which a plurality of nozzles are arranged in an annular shape.

[0004] In this type of nozzle head, when spraying paint with the nozzles facing horizontally, problems may occur due to the head difference between the upper nozzles and the lower nozzles. In the nozzle head described in Patent Document 1, a resistance portion is provided in the paint flow path, and the head difference between the upper and lower nozzles is alleviated.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In a third embodiment of the invention described in Patent Document 1, the nozzle head has a first head portion and a second head portion, and a space is formed between the tip of the first head portion and the base end of the nozzle provided on the second head portion. This space serves to distribute the paint to each nozzle. However, when such a space is provided, the volume of the paint flow path inside the nozzle head becomes relatively large, which tends to result in a large amount of paint being discarded when changing the type of paint (commonly referred to as "changing colors").

[0007] Therefore, it is possible to suppress the volume of the paint flow path within the nozzle head while avoiding problems caused by differences in water head between nozzles. Paint chamber unit for electrostatic atomizing paint machine and There is a need to develop a nozzle head for electrostatic atomizing paint machines. [Means for solving the problem]

[0008] The paint chamber unit for an electrostatic atomizing coating machine according to the first invention of the present invention comprises a paint chamber extending across a plurality of nozzles, a row of outlets connected to each of the plurality of nozzles arranged in a line, and an inlet into which paint flows, and an on / off valve for switching whether or not paint can flow into the inlet, wherein the width of the paint chamber along the row of outlets gradually increases from the inlet toward the row of outlets Furthermore, the width along the direction perpendicular to the extending direction of the paint chamber gradually decreases from the inlet to the outlet row. The nozzle head for an electrostatic atomizing paint machine of the second invention according to the present invention comprises a plurality of nozzles, a row of outlets connected to each of the plurality of nozzles arranged in a line, an inlet into which paint flows, a paint chamber extending from the inlet, and an on / off valve for switching whether or not paint flows into the inlet, wherein the width of the paint chamber along the row of outlets gradually increases from the inlet towards the row of outlets. Furthermore, the width along the direction perpendicular to the extending direction of the paint chamber gradually decreases from the inlet to the outlet row. It is characterized by having multiple paint chamber units.

[0009] These This configuration allows for a reduced width of the paint chamber at the inlet, making it easier to control the volume of the paint chamber. Furthermore, because the width of the paint chamber gradually increases from the inlet to the outlet row, the paint flow velocity towards each outlet (nozzle) tends to become more uniform, thus reducing the likelihood of problems caused by differences in hydrostatic head.

[0010] Further features and advantages of the present invention will become clearer through the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0011] [Figure 1] This is a side view of the nozzle head according to the embodiment. [Figure 2] This is a front view of the nozzle head according to the embodiment. [Figure 3] This is a schematic cross-sectional view of the paint chamber according to the embodiment. [Figure 4] This is a view of the paint chamber according to the embodiment, seen from the direction of the nozzle head tip. [Figure 5] This is a schematic cross-sectional view of the paint chamber according to the embodiment. [Figure 6] These are a side view and a front view of the nozzle head according to a modified example. [Modes for carrying out the invention]

[0012] Embodiments of the nozzle head for electrostatic atomizing paint machines according to the present invention will be described with reference to the drawings. Below, an example will be described in which the nozzle head for electrostatic atomizing paint machines according to the present invention is applied to a nozzle head 1 for an electrostatic atomizing paint machine that paints an object to be coated by spraying paint.

[0013] [Nozzle head configuration] In this embodiment, the nozzle head 1 is attached to the opposite side of the main body B, which is connected to the work arm of a painting robot (not shown), when in use (Figures 1 and 2).

[0014] The nozzle head 1 comprises a distribution passage 2, an on-off valve 3, a paint chamber 4, and a nozzle 5. More specifically, there is one annular distribution passage 2 that is in fluid communication with a paint source (not shown), and this distribution passage 2 is connected to four paint chambers 4. The on-off valves 3 are provided to open and close the connections from the distribution passage 2 to each paint chamber 4, and therefore four on-off valves 3 are provided. Multiple nozzles 5 are connected to each paint chamber 4. The nozzles 5 are also arranged in an annular shape at the tip of the nozzle head 1 (Figure 2). In other words, in this embodiment, four paint chamber units are provided, each containing multiple nozzles 5, paint chambers 4, and on-off valves 3.

[0015] The electrostatic atomizing paint machine is equipped with a voltage application device (not shown) that applies a potential difference between the object to be coated and the nozzle head 1. The paint discharged from the nozzle 5 becomes charged by the high voltage applied by this voltage application device. Furthermore, the high voltage applied by this voltage application device creates an electric field around the opening of the nozzle 5. The charged paint ejected from each nozzle 5 is atomized as so-called electrostatic spray by the action of the electric field formed around the opening of each nozzle 5. The atomized charged paint is then electrostatically attracted to the object to be coated due to the potential difference between the nozzle head 1 and the object to be coated, and flies towards the object, adhering to its surface.

[0016] The paint chamber 4 has an inlet 41 into which paint flows, and multiple outlets 42 connected to each of the multiple nozzles 5 (Figures 3 and 4). The multiple outlets 42 form an outlet row 43 arranged in a line, and the paint chamber 4 extends from the inlet 41 to the outlet row 43. Corresponding to the annular arrangement of the nozzles 5 as described above, the outlet row 43 is curved (arc-shaped). Therefore, the paint chamber 4 has a curved shape at the tip of the nozzle head 1. For convenience, the paint chamber 4 is shown in a planar view in Figure 3.

[0017] The width along the outlet row 43 of the paint chamber 4 (hereinafter simply referred to as "the width of the paint chamber 4") gradually increases from the inlet 41 toward the outlet row 43. The width of the paint chamber 4 is the width along the direction (circumferential direction) along the curve of the outlet row 43, and this direction is indicated by reference symbol C in FIGS. 3 and 4. Specifically, the width of the paint chamber 4 is substantially the same as the inner diameter of the inlet 41 on the proximal end side (the side of the distribution path 2, which is the left side in FIG. 3), and is substantially the same as the length of the outlet row 43 on the distal end side (the side of the nozzle 5, which is the right side in FIG. 3), and the width increases substantially linearly from the proximal end side toward the distal end side in the region therebetween.

[0018] Also, the width along the direction orthogonal to the extending direction of the paint chamber 4 (hereinafter referred to as "the thickness of the paint chamber 4") gradually decreases from the inlet 41 toward the outlet row 43 (FIG. 5). The extending direction of the paint chamber 4 is the direction from the proximal end side toward the distal end side, and this direction is indicated by reference symbol L (the left - right direction of the paper surface) in FIG. 3. The direction R orthogonal to the direction L is the direction orthogonal to the paper surface of FIG. 3 and is the radial direction of the curve of the outlet row 43. The thickness of the paint chamber 4 is substantially the same as the inner diameter of the inlet 41 on the proximal end side, and is substantially the same as the inner diameter of the outlet 42 on the distal end side, and the thickness decreases substantially linearly from the proximal end side toward the distal end side in the region therebetween.

[0019] Drawing A in FIG. 3 is an enlarged view of the end of the outlet row 43. At the end of the outlet row 43, the inner surface 44 of the paint chamber 4 extending along the extending direction (direction L) of the paint chamber 4 is flush with the inner surface 51 of the nozzle 5a connected to the outlet 42a located at the end of the outlet row 43. Thereby, the resistance when the paint flows into the nozzle 5a at the end can be suppressed, and it is easy to realize a uniform flow of the paint to the nozzle 5a.

[0020] The distribution channel 2 is an annular pipe that communicates fluidly with the paint source via the main body B. The distribution channel 2 is connected to the inlets 41 of the paint chambers 4 at four locations and plays the role of distributing the paint supplied from the paint source to four sets of paint chamber units. Preferably, the inner diameter of the distribution channel 2 is selected such that the flow velocity of the paint in the distribution channel 2 is slower than the flow velocity of the paint in the paint chambers 4 and nozzles 5. In this embodiment, the distribution channel 2 and the inlets 41 are connected via a short pipe. The on-off valve 3 is provided at the connection point from the distribution channel 2 to the inlets 41 and switches whether or not paint can flow into the inlets 41 by opening and closing this connection point. The on-off valve 3 can be powered by any power source such as electricity, pneumatics, or hydraulics.

[0021] In this embodiment, 100 nozzles 5 are provided at equal intervals. Therefore, 25 nozzles 5 are connected to each paint chamber 4. The distance between adjacent nozzles 5 is 3 mm. These values ​​are merely examples to aid in understanding this embodiment and do not limit the present invention.

[0022] In this embodiment, each nozzle 5 is implemented as a straight tube with an outer diameter of 0.8 mm, an inner diameter of 0.3 mm, a wall thickness of 0.25 mm, and a length of 60 mm. The dimensions of the nozzle 5 are appropriately selected according to the properties of the paint used (type of solvent, viscosity, solid content concentration, etc.) and the size of the object to be coated. In particular, it is preferable to set the dimensions with consideration for suppressing variations in the discharge amount between nozzles 5 and preventing paint dripping from the tip of the nozzle 5 by utilizing capillary action. For example, an inner diameter of 0.2 mm or more and 1.0 mm or less is preferable because it makes it easier to achieve uniform discharge amounts from multiple nozzles 5. In addition, the length of the nozzle 5 is preferably 5 mm or more and 100 mm.

[0023] Furthermore, it is preferable that the inner diameter of the tip of the nozzle 5 is between 0.2 mm and 0.7 mm, as this makes it easier to avoid problems caused by differences in water head between nozzles (such as dripping and air inflow). As can be seen from the fact that a preferred dimension for the inner diameter of the tip is specified here, the inner diameter of the nozzle 5 may be uniform throughout its entire length, or it may have different inner diameters in different parts.

[0024] In addition, when the nozzle head 1 is positioned so that the nozzle 5 extends horizontally, it is preferable that the head difference, which is the difference between the head pressure at the highest position of the nozzle 5 and the head pressure at the lowest position of the nozzle 5, is within 10% of the head pressure at the lowest position of the nozzle 5.

[0025] Furthermore, the dimensions of the nozzle 5 and the dimensions of the paint chamber 4 can be determined in conjunction with each other. Directly, since the outlet 42 of the paint chamber 4 is connected to the nozzle 5, the inner diameter of the outlet 42 can match the inner diameter of the nozzle 5. In this embodiment, the inner diameter of the outlet 42 is set to 0.3 mm. Also, the inner diameter of the inlet 41 is determined to a level that can achieve a supply capacity that can uniformly supply paint to all nozzles 5. In this embodiment, the inner diameter of the inlet 41 is set to 3 mm. Therefore, in this embodiment, the cross-sectional area of ​​the flow path in the nozzle 5 is smaller than the cross-sectional area of ​​the inlet 41.

[0026] [Effects of the nozzle head] In the nozzle head 1 according to this embodiment, the width of the paint chamber 4 gradually increases from the inlet 41 to the outlet row 43, making it easier to achieve a uniform paint flow velocity toward each outlet 42 (nozzle 5). Furthermore, the structure is designed to minimize steps around the inlet 41 and each outlet 42, thus reducing paint stagnation. In addition, since there is no need to provide an on-off valve to open and close each nozzle inside the paint chamber 4, the volume of the paint chamber 4 can be reduced compared to conventional nozzle heads of the same type. This reduces the amount of paint discarded when changing colors. Moreover, the absence of an on-off valve simplifies the structure inside the paint chamber compared to conventional designs, making it easier to clean the nozzle head when changing colors. The ability to reduce the width of the paint chamber on the inlet 41 side also contributes to reducing the volume of the paint chamber 4.

[0027] [Variation] In the nozzle head 6 shown in Figure 6, the nozzle 5 is arranged linearly at the tip of the nozzle head 6. In this case as well, a paint chamber 4 with the same configuration as in the above embodiment can be provided. In the present invention, the arrangement of the nozzles is not limited to the above embodiments (Figures 1-5) and modified examples (Figure 6).

[0028] [Other Embodiments] Finally, other embodiments of the nozzle head for electrostatic atomizing coating machine according to the present invention will be described. Note that the configurations disclosed in each of the following embodiments can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise.

[0029] In the above embodiment, a configuration in which an on-off valve 3 is provided at the connection between the inlet 41 and the distribution path 2 was described as an example. However, the position of the on-off valve in the present invention is not limited as long as it can switch whether or not paint flows into the inlet.

[0030] In the above embodiment, a configuration in which the nozzle head 1 has multiple paint chambers 4 was described as an example. However, in the present invention, there may be one paint chamber or multiple paint chambers.

[0031] In the above embodiment, the cross-sectional area of ​​the flow path in the nozzle 5 is smaller than the cross-sectional area of ​​the inlet 41. i structure The example given was used for this explanation. However, in the present invention, the relationship between the cross-sectional area of ​​the flow path and the cross-sectional area of ​​the inlet in the nozzle is not limited.

[0032] Other embodiments of the present invention include the following aspects (1) to (7).

[0033] (1) The present invention is Multiple nozzles, A paint chamber extending across a row of outlets, each of which is connected to one of the multiple nozzles, and an inlet into which the paint flows, and The system includes an on / off valve that switches whether or not paint can flow into the inlet, The nozzle head for the electrostatic atomizing paint machine may have a width along the row of outlets in the paint chamber that gradually increases from the inlet to the row of outlets.

[0034] (2) The present invention is The system comprises multiple paint chamber units, each including multiple nozzles, paint chambers, and on / off valves. It includes a distribution path that distributes paint supplied from a paint source to a plurality of paint chamber units, The nozzle head for an electrostatic atomizing paint machine described in (1) is such that the inlet of each paint chamber unit is connected to the distribution passage, and the on / off valve of each paint chamber unit opens and closes the connection between the distribution passage and the inlet of the paint chamber unit.

[0035] (3) The present invention is The nozzle head for the electrostatic atomizing coating machine described in (1) or (2) is such that the width along a direction perpendicular to the extending direction of the paint chamber gradually decreases from the inlet to the outlet row.

[0036] (4) The present invention is The nozzle head for an electrostatic atomizing coating machine according to (1) or (2) is such that the inner surface of the paint chamber extending along the direction of extension of the paint chamber is formed flush with the inner surface of the nozzle connected to the outlet located at the end of the outlet row.

[0037] (5) The present invention is The nozzle head for the electrostatic atomizing coating machine described in (1) or (2) is such that the inner diameter of the tip of the nozzle is 0.2 mm or more and 0.7 mm or less.

[0038] (6) The present invention is The nozzle head for the electrostatic atomizing coating machine described in (1) or (2) is such that the inner diameter of the nozzle is 0.2 mm or more and 1.0 mm or less.

[0039] (7) The present invention is The nozzle head for the electrostatic atomizing paint machine described in (1) or (2) is such that the length of the nozzle is 5 mm or more and 100 mm or less.

[0040] With regard to other configurations, the embodiments disclosed herein are illustrative in all respects, and it should be understood that the scope of the present invention is not limited thereto. Those skilled in the art will readily understand that modifications can be made as appropriate without departing from the spirit of the invention. Therefore, other embodiments modified without departing from the spirit of the invention are naturally included within the scope of the present invention. [Explanation of Symbols]

[0041] 1: Nozzle head 2: Distribution path 3: Shut-off valve 4:Paint room 41:Inlet 42: Outlet 43: Outlet row 44: Inner self 5: Nozzle 51: Inner self 6: Nozzle head (modified version)

Claims

1. Multiple nozzles, A paint chamber extending across a row of outlets, each of which is connected to one of the multiple nozzles, and an inlet into which the paint flows, and The system includes an on / off valve that switches whether or not paint can flow into the inlet, A paint chamber unit for an electrostatic atomizing coating machine, wherein the width of the paint chamber along the row of outlets gradually increases from the inlet towards the row of outlets, and the width along a direction perpendicular to the extending direction of the paint chamber gradually decreases from the inlet towards the row of outlets.

2. Multiple nozzles, A paint chamber extending across a row of outlets, each of which is connected to one of the multiple nozzles, and an inlet into which the paint flows, and The system includes an on / off valve that switches whether or not paint can flow into the inlet, A nozzle head for an electrostatic atomizing coating machine comprising a plurality of paint chamber units, wherein the width of the paint chamber along the row of outlets gradually increases from the inlet to the row of outlets, and the width along a direction perpendicular to the extending direction of the paint chamber gradually decreases from the inlet to the row of outlets.

3. The system further includes a distribution path for distributing paint supplied from a paint source to a plurality of paint chamber units. The nozzle head for an electrostatic atomizing painter according to claim 2, wherein the inlet of each paint chamber unit is connected to the distribution path, and the on / off valve of each paint chamber unit opens and closes the connection between the distribution path and the inlet of the paint chamber unit.

4. The nozzle head for an electrostatic atomizing coating machine according to claim 2 or 3, wherein the inner surface of the paint chamber extending along the extending direction of the paint chamber is formed flush with the inner surface of the nozzle connected to the outlet located at the end of the outlet row.

5. The nozzle head for an electrostatic atomizing coating machine according to claim 2 or 3, wherein the inner diameter of the tip of the nozzle is 0.2 mm or more and 0.7 mm or less.

6. The nozzle head for an electrostatic atomizing coating machine according to claim 2 or 3, wherein the inner diameter of the nozzle is 0.2 mm or more and 1.0 mm or less.

7. The nozzle head for an electrostatic atomizing painter according to claim 2 or 3, wherein the length of the nozzle is 5 mm or more and 100 mm or less.

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