Electrostatic atomization head and electrostatic atomization coating device

Abstract

To provide an electrostatic atomizing head that can increase an amount of a coating material discharged from an existing electrostatic coating head and sufficiently achieve atomization of a droplet of coating material, and to provide an electrostatic atomizing coating applying device.SOLUTION: An electrostatic atomizing head 1 includes: a bowl-like body part 2 having conductivity; and a plurality of flow passage parts 3 provided while projecting from an outer edge part 24 of the body part 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electrostatic atomization head and an electrostatic atomization coating device. [Background technology]

[0002] Painting robots are widely used to automate painting of automobile bodies and the like. As one type of general painting robot, an industrial robot equipped with a painting nozzle at its tip is widely used. Such nozzles have various structures according to the painting method.

[0003] For example, JP 2018-8253 A (Patent Document 1) discloses an electrostatic spraying device used when performing electrostatic coating. The electrostatic spraying device of Patent Document 1 is equipped with a nozzle head in which multiple nozzles are arranged in a circular ring. In addition, JP 2019-55345 A (Patent Document 2) discloses an electrostatic atomizing head that releases paint by centrifugal force. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-8253 A [Patent Document 2] JP 2019-55345 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the electrostatic spraying device as in Patent Document 1 may discharge a small amount of paint per unit time, resulting in low painting efficiency.Also, with the rotary head as in Patent Document 2, the electric field strength at the edge of the rotary head may be low, resulting in insufficient atomization of paint droplets by the electrostatic effect.

[0006] Therefore, there is a need to realize an electrostatic atomization head and electrostatic atomization coating device that can discharge a larger amount of paint than conventional electrostatic coating heads and can sufficiently achieve fine paint droplets. [Means for solving the problem]

[0007] The electrostatic atomization head according to the present invention is a head for electrostatic atomization that is used by rotating, and includes a conductive, cup-shaped main body and a plurality of flow passages protruding from an outer edge portion of the main body. The equivalent diameter of the tip of the flow path in the flow path portion is 0.11 mm or more and 0.50 mm or less. It is characterized by the above.

[0008] The electrostatic atomization coating device according to the present invention includes an electrostatic atomization head, a paint supply source capable of supplying paint to the electrostatic atomization head, a drive device capable of rotating the electrostatic atomization head, and a power supply device capable of applying a voltage to the electrostatic atomization head, and the electrostatic atomization head includes a conductive, cup-shaped main body portion, and a plurality of flow passage portions provided protruding from an outer edge portion of the main body portion. The equivalent diameter of the tip of the flow path in the flow path portion is 0.11 mm or more and 0.50 mm or less. It is characterized by the above.

[0009] According to these configurations, the flow path protruding from the outer edge of the main body allows the electric field to concentrate at the tip of the flow path, which makes it easier to atomize the paint compared to conventional rotary heads that do not have a flow path. Also, since the rotary head mechanism is provided, it is easier to increase the amount of paint discharged compared to conventional electrostatic spray heads. In addition, by providing a flow path that is wider than in conventional technology, it is possible to effectively prevent the flow path from being blocked by paint, and since the electric field tends to concentrate at the tip of the flow path, the paint droplets ejected tend to be small.

[0010] Preferred embodiments of the present invention will be described below. However, the scope of the present invention is not limited to the preferred embodiments described below.

[0011] In one aspect, the electrostatic atomization head according to the present invention preferably further includes a guide member that guides the paint flowing toward the outer edge portion of the main body portion to the flow path portion.

[0012] According to this configuration, almost all of the paint discharged from the electrostatic atomization head can be discharged via the flow path portion.

[0013] In one aspect of the electrostatic atomization head according to the present invention, the flow path portions are preferably provided at equal intervals along the outer edge portion of the main body portion.

[0014] This configuration makes it easier for the electric field formed around each flow path to be uniform, which in turn makes it easier for the paint to be discharged from each flow path (such as the size and flight direction of the paint droplets) to be uniform, facilitating stable coating quality.

[0017] In one aspect of the electrostatic atomization head according to the present invention, the length by which the flow path portion protrudes from the outer edge portion of the main body portion is preferably 1 mm or more and 20 mm or less.

[0018] According to this configuration, a large electric field strength can be easily obtained at the tip of the flow path portion.

[0019] Further features and advantages of the present invention will become more apparent from the following description of exemplary and non-limiting embodiments, which are given with reference to the drawings. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic diagram of an electrostatic atomization coating device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a perspective view of the electrostatic atomization head according to the embodiment. [Diagram 3] 3 is an enlarged view of a portion III in FIG. 2 surrounded by a dashed dotted line. [Figure 4] 3 is a cross-sectional view of a flow path of the electrostatic atomization head according to the embodiment. FIG. [Diagram 5] FIG. 13 is a schematic diagram of an electrostatic atomization coating device according to a modified example. [Figure 6] FIG. 13 is a perspective view of an electrostatic atomization head according to a modified example. [Figure 7] FIG. 7 is an enlarged view of a portion VII enclosed by a dashed dotted line in FIG. [Figure 8] 13 is a cross-sectional view of a flow path of an electrostatic atomization head according to a modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] An embodiment of the electrostatic atomization head and electrostatic atomization coating device according to the present invention will be described with reference to the drawings. In the following, an example in which the electrostatic atomization head and electrostatic atomization coating device according to the present invention are applied to an electrostatic atomization coating device 100 used for coating automobile bodies and the like, and an electrostatic atomization head 1 provided therein will be described. As will be described in detail later, the electrostatic atomization coating device 100 is provided with an electrostatic atomization head 1, a paint supply source 11, a drive device 12, and a power supply device 13, and is a device that atomizes and discharges paint supplied from the paint supply source 11 to the electrostatic atomization head 1.

[0022] [Configuration of electrostatic atomization head] The electrostatic atomization head 1 according to this embodiment includes a main body portion 2, a flow path portion 3, and a guide member 4 (FIG. 1).

[0023] The main body 2 is formed in a bowl shape. The main body 2 has a bowl-shaped body 21 and a diffusion plate 22 provided in the center part of the bowl-shaped body 21 (corresponding to the bottom part of the bowl). A gap 23 is provided between the bowl-shaped body 21 and the diffusion plate 22. The main body 2 is configured to be rotatable around an axis X, and a driving force for the rotation can be supplied by a driving device 12.

[0024] The main body 2 is conductive. More specifically, in the main body 2, at least the cup-shaped body 21 is made of a conductive material. Here, the conductive material is a material having a volume resistivity of 10 12 The volume resistivity of a conductive material is, for example, 10 Ω·cm or less, and examples of the material include, but are not limited to, metals and conductive grade resin materials. The lower limit of the volume resistivity of a conductive material is not particularly limited, and the volume resistivity is, for example, 10 8 It can be more than Ω·cm.

[0025] The flow path section 3 is a tubular member protruding from the outer edge portion 24 of the main body section 2 (bowl-shaped body 21), and multiple flow path sections 3 are provided (FIGS. 1 to 3). Since the flow path section 3 protrudes from the outer edge portion 24 of the main body section 2, an electric field is concentrated at the tip of the flow path section 3. This makes it easier to atomize the paint compared to a conventional rotary head that does not have a flow path section 3.

[0026] The flow path sections 3 are provided at equal intervals (2 mm intervals in this embodiment) along the outer edge portion 24 of the main body section 2. When the flow path sections 3 are provided at equal intervals, the relative positional relationships of the multiple flow path sections 3 become uniform, and therefore the electric field formed around each flow path section 3 tends to become uniform. This tends to make the manner in which the paint is discharged from each flow path section 3 (the size of the paint droplets, the flight direction, etc.) uniform, and tends to stabilize the coating quality.

[0027] In this embodiment, the inner diameter W of the flow path 31 is 0.15 mm, and the inner diameter W is constant from the base end to the tip of the flow path section 3. In particular, if the inner diameter W at the tip of the flow path 31 is 0.11 mm or more, a flow path with a wider width can be provided compared to the conventional technology, and the flow path 31 is less likely to be clogged with paint, which is preferable. The inner diameter W at the tip of the flow path 31 is more preferably 0.15 mm or more. Also, if the inner diameter W at the tip of the flow path 31 is 0.50 mm or less, an electric field is likely to concentrate at the tip of the flow path 31, which makes it easier for the paint droplets discharged from the electrostatic atomization head 1 to become smaller, which is preferable. The inner diameter W at the tip of the flow path 31 is more preferably 0.20 mm or less.

[0028] The flow path section 3 is provided so as to protrude 5 mm from the outer edge portion 24. When the length L by which the flow path section 3 protrudes from the outer edge portion 24 (hereinafter referred to as "protrusion length L of the flow path section 3") is 1 mm or more, a large electric field strength is likely to be obtained at the tip of the flow path section 3. It is more preferable that the protrusion length L of the flow path section 3 is 3 mm or more. Furthermore, from the viewpoint of ensuring that the strength of the flow path section 3 is at a certain level or higher, it is preferable that the protrusion length L of the flow path section 3 is 20 mm or less. It is more preferable that the protrusion length L of the flow path section 3 is 10 mm or less.

[0029] In this embodiment, the protruding length L (5 mm) of the flow path section 3 is 33 times the inner diameter W (0.15 mm) at the tip of the flow path 31. The protruding length L of the flow path section 3 is preferably 10 to 40 times the inner diameter W at the tip of the flow path 31.

[0030] The flow path section 3 according to this embodiment is conductive. More specifically, the flow path section 3 is formed of a conductive material. Here, the definition of the conductive material is as described above. The conductive material may be the same material as the conductive material forming the bowl-shaped body 21, or may be a different material. Note that it is preferable for the flow path section 3 to be conductive, since a voltage drop in the paint is unlikely to occur from the base end to the tip end of the flow path section 3.

[0031] In this case, it is preferable that the tip portion of the flow path section 3 is made of an insulating material. When the tip portion of the flow path section 3 is made of an insulating material, a voltage is applied only to the portion (flow path 31) at the tip portion of the flow path section 3 through which the paint flows. This causes a non-uniform electric field to concentrate only on the paint droplets, and the paint droplets are efficiently charged, which can improve the ability to finely divide the paint droplets compared to conventional nozzle heads. The length of the portion made of the insulating material can be, for example, 1.0 to 3.0 mm.

[0032] The guide member 4 is a member that guides the paint flowing along the main body 2 (the inner surface of the bowl-shaped body 21) toward the outer edge portion 24 to the flow path portion 3. Specifically, the guide member 4 is provided as a weir-like structure near the outer edge portion 24 of the inner surface of the bowl-shaped body 21 (FIGS. 1 to 3). As shown by the arrow in FIG. 3, the paint flowing toward the outer edge portion 24 is guided by the guide member 4 to reach the flow path portion 3, and so almost no paint reaches the portion of the outer edge portion 24 where the flow path portion 3 is not provided. As a result, almost all of the paint discharged from the electrostatic atomization head 1 passes through the flow path portion 3.

[0033] [Configuration of electrostatic atomization coating device] The electrostatic atomization coating device 100 according to this embodiment includes an electrostatic atomization head 1, a paint supply source 11, a driving device 12, and a power supply device 13 (FIG. 1). The configuration of the electrostatic atomization head 1 is as described above.

[0034] The paint supply source 11 is a device capable of supplying paint to the electrostatic atomization head 1, and may be a known device capable of supplying paint to a head portion in a coating device. The paint supply source 11 may include, for example, a paint tank, a pump, a flow rate control valve, a paint supply pipe, and the like. In this embodiment, only the paint supply pipe 11a is illustrated as a part of the paint supply source 11 (FIG. 1). The tip portion of the paint supply pipe 11a is inserted into the center portion of the main body 2 (the bowl-shaped body 21) from the base end side of the bowl-shaped body 21, and the paint discharged from the paint supply pipe 11a is configured to hit the diffusion plate 22 from the base end side.

[0035] The driving device 12 is a device that can rotate the electrostatic atomization head 1 around the axis X. In this embodiment, the driving device 12 is implemented as a known air motor, and is operated using compressed air supplied from a compressor (not shown) as a driving force, for example.

[0036] The power supply device 13 is a device that can apply a voltage to the electrostatic atomization head 1. In this embodiment, the power supply device 13 is implemented as a known power supply device.

[0037] When paint is supplied from the paint supply source 11 to the electrostatic atomization head 1 in a rotating state, the paint hits the diffusion plate 22 and is diffused, and reaches the inner surface of the bowl-shaped body 21 through the gap 23. The paint is further guided outward along the inner surface of the bowl-shaped body 21 by centrifugal force, and reaches the flow path section 3 provided on the outer edge portion 24 of the main body 2 (bowl-shaped body 21).

[0038] [Modification of the flow path section] In the above embodiment, the flow path portion 3 is provided as a tubular member. However, in the electrostatic atomization head and electrostatic atomization coating device according to the present invention, the shape of the flow path portion is not particularly limited. For example, the flow path portion may be a gutter-shaped member (FIGS. 5 to 8).

[0039] The flow path section 5 according to the modified example is configured as a gutter-shaped member. In the flow path section 5, a flow path 51 having a rectangular cross section is formed, and the width Wa thereof is constant (FIGS. 5 to 8).

[0040] In the flow path section 5, a cross section perpendicular to the flow path 51 opens on the axis X side (FIGS. 6 and 8). As the main body 2 rotates around the axis X when the paint flows through the flow path section 5, the paint receives a force (centrifugal force) in a direction away from the axis X. Therefore, the paint flowing through the flow path section 5 flows along the radially outer surface 52 of the electrostatic atomization head 1. Therefore, even if the flow path section 5 has an opening on the axis X side, the paint can flow to the tip of the flow path section 5 (flow path 51).

[0041] 5 to 8 show an example in which the cross-sectional shape of the flow path 51 is rectangular, but when the flow path portion is formed in a gutter shape, the shape of the flow path is not particularly limited as long as the opening of the flow path is provided on the axial center side of the main body portion. For example, the cross-sectional shape of the flow path may be semicircular or trapezoidal.

[0042] Also, in the case where the flow path section 3 is provided as a tubular member like the flow path section 3 in the above embodiment, the shape of the tubular member and the shape of the flow path are not particularly limited. When the flow path section is formed in a tubular shape, the tubular member may be cylindrical, conical, elliptical cylinder, elliptical cone, prism, pyramid, etc. The cross-sectional shape of the flow path may be circular, elliptical, polygonal, etc. The equivalent diameter of the tip of the flow path is determined as the diameter of a circle having the same area as the cross-sectional area at the tip of the flow path, regardless of the shape of the cross section. When the cross section is circular like the flow path 31 in the above embodiment, the equivalent diameter coincides with the diameter of the cross-sectional circle.

[0043] Other embodiments Finally, other embodiments of the electrostatic atomization head and electrostatic atomization coating device according to the present invention will be described. Note that the configurations disclosed in the following embodiments can be combined with the configurations disclosed in other embodiments as long as no contradiction occurs.

[0044] In the above embodiment, an example has been described in which the guide member 4 is provided. However, the electrostatic atomization head and electrostatic atomization coating device according to the present invention do not necessarily have to be provided with a guide member.

[0045] In the above embodiment, the flow path portions 3 are provided at equal intervals (2 mm intervals) along the outer edge portion 24 of the main body portion 2. However, in the electrostatic atomization head and electrostatic atomization coating device according to the present invention, the flow path portions do not have to be provided at equal intervals. In addition, when the flow path portions are provided at equal intervals, the intervals are not limited.

[0046] In the above embodiment, the inner diameter W (0.15 mm) at the tip of the flow path 31 and the protruding length L (5 mm) of the flow path portion 3 are both examples, and the dimensions of each part of the electrostatic atomization head and electrostatic atomization coating device of the present invention are not limited.

[0047] Regarding other configurations, it should be understood that the embodiments disclosed in this specification are illustrative in all respects and that the scope of the present invention is not limited thereto. A person skilled in the art would easily understand that appropriate modifications are possible without departing from the spirit of the present invention. Therefore, other embodiments modified without departing from the spirit of the present invention are naturally included in the scope of the present invention. [Industrial Applicability]

[0048] The present invention can be used in an electrostatic atomization coating device used, for example, for painting automobile bodies and the like. [Explanation of symbols]

[0049] 1: Electrostatic atomization head 2: Main body 21: Bowl-shaped body 22: Diffuser 23: Gap 24: Outer edge 3: Flow path section 31: Flow path 4: Guide member 5: Flow path section (modified example) 51: Flow path (variant) 52: Radial outer surface 11:Paint supply source 11a: Paint supply pipe 12: Drive unit 13: Power supply 100: Electrostatic atomizing coating device X: Axial center

Claims

1. An electrostatic atomization head that is rotated and used, A conductive bowl-shaped main body; A plurality of flow path portions protruding from an outer edge portion of the main body portion, The equivalent diameter of the tip of the flow path in the flow path portion is 0.11 mm or more and 0.50 mm or less.

2. The electrostatic atomization head according to claim 1 , further comprising a guide member that guides the paint flowing toward the outer edge portion of the main body to the flow path portion.

3. The electrostatic atomization head according to claim 1 , wherein the flow passages are provided at equal intervals along the outer edge of the main body.

4. 4. The electrostatic atomization head according to claim 1, wherein the length of the flow passage portion protruding from the outer edge portion of the main body portion is 1 mm or more and 20 mm or less.

5. An electrostatic atomization head; A paint supply source capable of supplying paint to the electrostatic atomization head; A drive device capable of rotating the electrostatic atomization head; A power supply device capable of applying a voltage to the electrostatic atomization head, The electrostatic atomization head includes: A conductive bowl-shaped main body; A plurality of flow path portions protruding from an outer edge portion of the main body portion, The electrostatic atomization coating device, wherein the equivalent diameter of the tip of the flow path in the flow path portion is 0.11 mm or more and 0.50 mm or less.

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