JP2020082039A - Masking jig and electrostatic atomizer - Google Patents

Abstract

To provide a masking jig which can improve masking workability for an object to be coated.SOLUTION: A masking jig 30 is used in an electrostatic atomizer which removes a liquid from a liquid spray part in a charged state by electrostatic force generated by applying voltage between the liquid spray part and a different pole part which becomes a different pole with respect to the liquid spray part, and sprays atomization liquid to an object 40 to be coated. The masking jig 30 comprises a cylindrical member 31 which covers a non-coating part of the object 40 to be coated which is not coated with a liquid. The cylindrical member 31 has an inner surface, an outer surface, and a connection surface 31a which connects the inner surface and the outer surface near an end surface. A closed curve CC is formed at a boundary between the connection surface 31a and the inner surface, the closed curve CC is larger than an outer periphery of the non-coating part, and the object 40 to be coated can be inserted in the closed curve.SELECTED DRAWING: Figure 5

Description

The present invention relates to a masking jig and an electrostatic spraying device.

Conventionally, a liquid such as paint is separated from the liquid spraying section in a charged state by an electrostatic force generated by applying a voltage between the liquid spraying section and a different polarity section having a different polarity with respect to the liquid spraying section, Electrospray deposition (ESD) is an electrostatic spraying device that sprays an atomized liquid onto an object to be coated, and a masking jig is attached to the object to form a thin film of a predetermined shape and pattern on the object. (See Patent Document 1).

The masking jig described in Patent Document 1 includes a masking main body and a masking auxiliary body, and the masking auxiliary body defines a coated portion of a coated object and a non-coated portion of the coated object. And the masking body is arranged so as to cover the non-application portion which is not covered by the masking auxiliary body, and the masking auxiliary body is formed by using a conductive material, and the masking body is formed by using an insulating material. Is formed.

JP, 2016-221433, A

However, the object to be coated in the ESD technical field generally has a flat coating portion as seen in Patent Document 1, so that the coating portion of the coating object may extend over a plurality of surfaces or a circle. Such a masking jig cannot be applied when the surface is a continuous surface such as a peripheral surface or when the object to be coated is a rod-shaped minute component. In addition, since a general masking jig for spray application is attached to the surface of the non-application part by adhesion or adhesion, if it is an object to be coated as described above, the operation of attaching the masking jig Need time to. Further, when the masking jig is peeled off after application, a part of the adhesive or the pressure-sensitive adhesive may remain after peeling off the masking jig, and it takes time to remove these.

Then, this invention is made|formed in view of the above subject, and an object of this invention is to provide the masking jig and electrostatic spraying apparatus which improve the masking workability with respect to a to-be-coated material.

(1) One aspect according to the present invention is that the liquid is charged in a charged state by an electrostatic force generated by applying a voltage between the liquid spray section and a different pole section having a different pole with respect to the liquid spray section. A masking jig used in an electrostatic spraying device for spraying an atomized liquid onto an object to be coated, which is separated from the liquid spray section, and includes a tubular member for covering a non-application section of the object to be coated with no liquid. The tubular member has an inner surface, an outer surface, and a connecting surface that connects the inner surface and the outer surface in the vicinity of an end surface, and a closed curve is formed at a boundary portion between the connecting surface and the inner surface, and the closed curve is , Larger than the outer circumference of the non-application portion, and into which the article to be coated can be inserted.
(2) In the aspect of (1) above, the tubular member may have a portion formed of an insulating material.
(3) In the aspect of (2) above, the maximum gap between the closed curve and the outer periphery of the non-application portion may be 2 mm or less.
(4) In the aspect of (1) above, the tubular member may have a portion formed of a conductive material or a semiconductive material.
(5) In the aspect of (4) above, the maximum gap between the closed curve and the outer periphery of the non-application portion may be 1 mm or less.
(6) In the aspect of (4) or (5), the tubular member may be covered with an insulating material at a portion other than the connection surface.
(7) In any one of the above aspects (1) to (6), in a cross-sectional view along the axis of the tubular member, the tubular member is separated from the point where the closed curve is formed by the thickness of the tubular member. The distance to the inner surface at a point on the connection surface may be 2 mm or less.
(8) In any one of the above aspects (1) to (7), the article to be coated may be an elongated article having the same cross-sectional shape in the longitudinal direction.
(9) In any one of the above aspects (1) to (8), the non-coated portion of the article may have a maximum outer diameter of 3 mm or less.
(10) According to another aspect of the present invention, the liquid is sprayed by an electrostatic force generated by applying a voltage between the liquid spraying section and a different pole section having a different pole with respect to the liquid spraying section. An electrostatic spraying device for spraying an atomized liquid onto an article to be coated by separating it from the liquid spraying section in a charged state, the masking jig including a cylindrical member covering a non-application section of the article to which the liquid is not applied A tubular member having an inner surface, an outer surface, and a connecting surface that connects the inner surface and the outer surface near an end surface, and a closed curve is formed at a boundary portion between the connecting surface and the inner surface. The closed curve is larger than the outer circumference of the non-application portion, the object to be coated can be inserted, and the liquid spraying portion is arranged in the axial direction orthogonal to the central axis of the tubular member.

According to the present invention, it is possible to provide a masking jig and an electrostatic spraying device that improve the workability of masking an object to be coated.

It is a perspective view showing the whole electrostatic spraying device composition using the masking jig of an embodiment concerning the present invention. It is sectional drawing which shows the whole structure of the electrostatic spraying device which uses the masking jig of embodiment which concerns on this invention. It is sectional drawing which shows the liquid spraying part of an electrostatic spraying device. It is an enlarged view showing the tip side of a liquid spraying part, when (a) the tip of a mandrel is located in the back, and (b) the tip of a mandrel is located in the front. It is a perspective view showing a masking jig of an embodiment concerning the present invention. It is explanatory drawing which shows the closed curve in the cylindrical member of embodiment. It is sectional drawing which shows the end surface part of a cylindrical member, (a) without chamfering, (b) with C chamfering, (c) with R chamfering. It is a perspective view which shows the masking jig of the modification 1 which concerns on this invention. FIG. 11 is an explanatory diagram showing a closed curve in the tubular member of Modification 1. It is the schematic which shows a mode that the width|variety of the application part in a to-be-coated article is changed from (a) W1 to (b) W2. It is a perspective view which shows the masking jig of the modification 2 which concerns on this invention. It is a perspective view which shows the masking jig of the modification 3 which concerns on this invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. In the embodiments of the present specification, the same members are designated by the same reference numerals throughout. Further, the terms “front (edge)” and “front (direction)” indicate the liquid spray direction side in each member, and the terms “rear (end)” and “rear (direction)” in each member. The direction opposite to the spray direction of the liquid is shown, and “left” and “right” indicate the case of viewing from the front to the rear.

First, before describing the masking jig 30 of the embodiment according to the present invention, the electrostatic spraying device 10 using the masking jig 30 will be described. FIG. 1 is a perspective view showing an overall configuration of an electrostatic spraying device 10 using a masking jig 30 according to an embodiment of the present invention. FIG. 2 is a sectional view showing the overall configuration of the electrostatic spraying device 10 using the masking jig 30 of the embodiment according to the present invention.

(Electrostatic spraying device)
As shown in FIGS. 1 and 2, the electrostatic spraying device 10 includes a liquid spraying section 20 having a liquid nozzle 22, a masking jig 30, and a heteropolar section 40 having a different polarity with respect to the liquid spraying section 20. A voltage applying unit (voltage power supply) 50 that applies a voltage between the liquid spray unit 20 and the liquid spraying unit 20.

In the present embodiment, the case where the electrical wiring from the voltage applying means (voltage power supply) 50 is directly connected to the article to be coated and the article to be coated itself is the heteropolar portion 40 is shown. An electric wire from a voltage applying means (voltage power source) 50 is connected to a mounting portion (not shown) on which the coating material is mounted, and this mounting portion serves as the heteropolar portion 40, and the coated portion is placed via the mounting portion. The coating material may be electrically connected to the voltage applying means (voltage power supply) 50. Further, the term “different polarity” does not mean only the relationship between the so-called positive electrode (positive electrode) and the negative electrode (negative electrode), but the relationship between the high potential and the low potential is the same. In addition, it also means a case where an electric field is formed by being relatively different in polarity.

An object to be coated (hereinafter referred to as “object to be coated 40”) that will be the different-polarity portion 40 is grounded by the grounding means 60. Although the grounding means 60 is not an indispensable component, the object 40 to be coated may be touched by an operator, so it is preferable to provide it from the viewpoint of safety.

(Liquid spray part)
FIG. 3 is a sectional view showing the liquid spraying section 20 of the electrostatic spraying device 10, and shows only the liquid spraying section 20. It should be noted that FIG. 3 also illustrates a state in which a liquid such as paint is sprayed from the liquid spraying unit 20 as described later.

As shown in FIG. 3, the liquid spray unit 20 includes a body portion 21 made of an insulating material in which a liquid flow path 21b having a liquid supply port 21a for supplying a liquid is formed, and a liquid body of which the through hole is the body portion 21. A liquid nozzle 22 provided at the tip of the body portion 21 so as to communicate with the flow passage 21b, and a mandrel 23 made of a conductive material arranged in the liquid flow passage 21b of the body portion 21 and in the through hole of the liquid nozzle 22. , Are provided.

The body portion 21 is provided with a hole portion 21c communicating with the liquid flow path 21b in order to take out the mandrel 23 to the rear end side, and a gap between the mandrel 23 is sealed in the hole portion 21c. A seal member 24 is provided to prevent liquid from leaking. Although the O-ring is used as the seal member 24 in the present embodiment, the seal member 24 is not limited to the O-ring and may be any one that can seal.

Then, a knob 23a made of an insulating material is provided at the rear end of the mandrel 23 located on the rear end side of the body 21 through the hole 21c, and the knob 23a penetrates almost the center of the knob 23a. An electric wiring connection portion 23b made of the provided conductive material is provided.

As shown in FIGS. 1 and 2, the electric wiring from the voltage applying means 50 is connected to the electric wiring connecting portion 23b. Then, as shown in FIG. 3, the mandrel 23 and the electric wire connecting part 23b are electrically connected by bringing the electric wire connecting part 23b into contact with the mandrel 23.

In the present embodiment, the mandrel 23 is used as the electrode on the liquid spraying section 20 side. However, for example, the liquid nozzle 22 of the liquid spraying section 20 is made of a conductive material, and the voltage applying means 50 is applied to the liquid nozzle 22. The liquid nozzle 22 may be used as an electrode on the liquid spraying section 20 side by connecting the electric wiring of FIG.

A female screw structure 21e is provided on the inner peripheral surface of the rear end opening 21d of the body portion 21 for screwing and connecting the knob portion 23a, while a male screw is provided on the tip outer peripheral surface of the knob portion 23a. A structure 23c is provided.

That is, the mandrel 23 is detachably attached to the body portion 21 by screwing the male screw structure 23c on the outer peripheral surface of the front end of the knob portion 23a into the female screw structure 21e of the rear end opening 21d of the body portion 21. .. Further, the mandrel 23 can be moved in the front-rear direction by adjusting the screwing amount of the knob 23a, and the position of the distal end surface 23d of the mandrel 23 can be adjusted in the front-rear direction.

The opening diameter of the opening 22b at the tip of the liquid nozzle 22 is formed with a large opening diameter of 0.2 mm. The opening diameter of the opening 22b of the liquid nozzle 22 is not limited to 0.2 mm. For example, in the case where the mandrel 23 is used, the opening diameter may be about 1.0 mm, clogging is unlikely to occur, and considering that clogging can be easily performed, 0.1 mm or more. Is more preferable, 0.2 mm or more is more preferable, and it is more preferable that it is larger than 0.2 mm.

On the other hand, the opening diameter of the opening 22b of the liquid nozzle 22 is preferably 1.0 mm or less, more preferably 0.8 mm or less, still more preferably 0.5 mm or less in consideration of atomization stability. Good to do.

4 is an enlarged view in which the tip side of the liquid spraying section 20 is enlarged, FIG. 4(a) is a case where the tip surface 23d of the mandrel 23 is located rearward, and FIG. 4(b) is FIG. This is a case where the tip end surface 23d of the mandrel 23 is located forward of the state of (a).

As shown in FIG. 4A, the liquid nozzle 22 has a tapered inner diameter portion (see range A) in which the inner diameter is tapered toward the opening 22b side and the taper angle is α. The mandrel 23 has a tapered portion (see range B) in which the outer diameter decreases toward the tip surface 23d and the taper angle is β.

The taper angle α of the tapered inner diameter portion of the liquid nozzle 22 is larger than the taper angle β of the tapered portion of the mandrel 23. The diameter of the tip surface 23d of the mandrel 23 is smaller than the opening diameter of the opening 22b of the liquid nozzle 22, but the tapered portion of the mandrel 23 has a diameter gradually increasing toward the rear end side. The liquid nozzle 22 is formed so as to have a larger diameter and a larger diameter than the opening diameter of the opening 22b of the liquid nozzle 22.

By thus forming the tip ends of the liquid nozzle 22 and the mandrel 23, the width of the gap formed between the liquid nozzle 22 and the mandrel 23 can be adjusted by moving the mandrel 23 in the front-back direction. The amount of the liquid discharged from the opening 22b of the liquid nozzle 22 can be adjusted.

Further, by moving the mandrel 23 further to the front side than in the state shown in FIG. 4B, the mandrel 23 comes into contact with the inner peripheral surface of the liquid nozzle 22 and closes the opening 22b of the liquid nozzle 22. Is possible. Therefore, it is possible to prevent the liquid in the liquid nozzle 22 from being dried by closing the opening 22b of the liquid nozzle 22 with the mandrel 23 when the liquid such as paint is not sprayed. It can suppress clogging.

(Heteropolar portion 40)
In the present embodiment, as described above, the case in which the article to be coated 40 is used as the different-polarity portion 40 is shown, and the electric wiring on the opposite side to the one connected to the mandrel 23 of the voltage applying means (voltage power supply) 50. Is connected to the article to be coated 40, so that the article to be coated 40 itself has a different polarity with respect to the liquid spraying section 20.

However, for example, when the article to be coated 40 is conveyed to a position where a liquid such as paint is applied by a conveyer or the like, the electrical wiring from the voltage applying means 50 is placed on the article to be coated 40 of the conveyer. The article 40 to be coated may be electrically connected to the voltage applying means 50 via the placing section so that the article is electrically connected to the placing section.

Returning to FIG. 3, a state in which the liquid is sprayed from the liquid spraying section 20 will be described, and then the masking jig 30 that allows the sprayed liquid to be applied only to a predetermined range of the article 40 to be coated. Will be described.

The liquid supplied to the liquid supply port 21a of the body portion 21 is further supplied to the tip side of the liquid nozzle 22, and static electricity due to the voltage applied between the object to be coated 40 (heteropolar portion 40) and the mandrel 23. Due to the force, it is pulled to the front side and separated and atomized forward.

It should be noted that the liquid may be supplied as long as the liquid lost by the spray is lost from the liquid spray unit 20 is sequentially supplied, and the opening 22b (more accurately, the opening 22b and the opening 22b) of the liquid nozzle 22 may be supplied. If the liquid is pressure-fed at a pressure such that the liquid is ejected from the gap between the mandrel 23), atomization may not be possible.

Then, as the electrostatic force pulling the liquid forward balances the adhesive force due to the surface tension and the viscosity to the tip surface 23d of the mandrel 23 and the tip outer peripheral edge 22a of the liquid nozzle 22, as shown in FIG. The liquid supplied to the tip side of the nozzle 22 forms a Taylor cone TC having a conical shape at the tip.

The Taylor cone TC is formed in such a manner that positive/negative charges are separated in the liquid by the action of an electric field, and the meniscus at the tip of the liquid nozzle 22 charged with excess charges is deformed into a conical shape. .. Then, the liquid is pulled straight from the tip of the Taylor cone TC by the electrostatic force, and then the liquid is sprayed in a wide range by the electrostatic explosion.

The liquid to be sprayed, that is, the liquid separated from the liquid nozzle 22 into liquid particles has a dramatically larger area in contact with air than in the state before separation, so that vaporization of the solvent is promoted and the solvent The distance between the charged electrons becomes shorter due to the vaporization, and electrostatic repulsion (electrostatic explosion) occurs, and the liquid particles are further divided into smaller liquid particles.

When this fragmentation occurs, the surface area in contact with air increases more than before the fragmentation, which promotes vaporization of the solvent, electrostatic explosion occurs as described above, and liquid with a small particle size Split into particles. The liquid is atomized by repeating such electrostatic explosion.

Here, in the present embodiment, the mandrel 23 is provided in the liquid nozzle 22, but if the mandrel 23 is not provided, the liquid can be attached only to the outer peripheral edge 22a of the tip of the liquid nozzle 22. ..

In this case, if the opening diameter of the opening 22b of the liquid nozzle 22 is increased, the liquid can be attached only to the outer peripheral edge 22a of the tip of the liquid nozzle 22, so that the liquid fluctuates in the vertical and horizontal directions of the liquid nozzle 22, for example. Stability of liquid particles leaving the liquid nozzle 22 (particle size, number, charge state, etc.) because it is difficult to form a clean Taylor cone TC or the Taylor cone TC itself cannot be maintained. Stability cannot be obtained, and as a result, stable atomization of the liquid cannot be achieved.

Therefore, in this embodiment, the mandrel 23 is arranged in the liquid nozzle 22, and the liquid adheres not only to the outer peripheral edge 22a of the liquid nozzle 22 but also to the front end surface 23d of the mandrel 23. Therefore, even if the opening diameter of the opening 22b of the liquid nozzle 22 is large, since the tip surface 23d of the mandrel 23 to which the liquid can adhere is present in the central portion of the opening 22b, a stable Taylor cone TC can be formed. It is thought that stable atomization of liquid is possible.

If the tip surface 23d of the mandrel 23 goes too far forward from the tip outer peripheral edge 22a of the liquid nozzle 22 (that is, the tip surface of the opening 22b of the liquid nozzle 22), it becomes difficult for the electric field to act on the liquid coming out of the liquid nozzle 22, On the other hand, if the tip surface 23d of the mandrel 23 is excessively retracted rearward from the tip surface of the opening 22b of the liquid nozzle 22, the state is the same as that where there is no portion where the liquid can adhere to the central portion of the opening 22b.

From this, the position of the tip surface 23d of the mandrel 23 is in the front-rear direction along the central axis of the mandrel 23 with respect to the tip surface of the opening 22b of the liquid nozzle 22 when the liquid is sprayed. It is preferable that it is located within 10 times the opening diameter of the opening 22b at the tip of 22, more preferably within 5 times, and even more preferably within 3 times. Is.

For example, in the present embodiment, the opening diameter of the opening 22b of the liquid nozzle 22 is 0.2 mm, and when the electrostatic force is not taken into consideration, the liquid discharged from the opening 22b of the liquid nozzle 22 is discharged at the tip of the liquid nozzle 22. It comes out in a hemispherical shape with a diameter of about 0.2 mm.

The tip of the mandrel 23 is located near the liquid so that an electric field (electrostatic force) acts on the liquid emerging from the tip of the liquid nozzle 22 to form a conical Taylor cone TC. Good. Therefore, it is preferable that the tip of the mandrel 23 is positioned within 2 mm forward (outward) from the tip surface of the opening 22b of the liquid nozzle 22, while the tip of the mandrel 23 is positioned so as to affect the attachment of the liquid. It is preferable that the nozzle 22 is positioned within 2 mm rearward (in the retracting direction) from the tip end surface of the opening 22b.

Thus, by providing the mandrel 23, the opening diameter of the opening 22b of the liquid nozzle 22 can be made large so that clogging can be suppressed. Further, since the opening diameter of the opening 22b of the liquid nozzle 22 can be increased, the liquid nozzle 22 can be manufactured by machining.

In the present embodiment, the tip of the mandrel 23 is shown as a flat surface as the tip surface 23d, but the tip of the mandrel 23 does not necessarily have to be a flat surface, and a stable Taylor cone TC Since it suffices to contribute to the formation, the tip end of the mandrel 23 may have a curved surface protruding toward the front side like an R shape, for example.

In this way, the liquid sprayed from the liquid spraying unit 20 (liquid nozzle 22) becomes an atomized liquid while repeating electrostatic explosion, and since the atomized liquid is in a state of being charged, the object to be coated is It is attracted to the 40 (heteropolar portion 40) side by electrostatic force and is applied to the article 40 to be coated.

(Coating object)
Here, the coated article 40 will be described. The coated article 40 is a long article having the same cross-sectional shape in the direction perpendicular to the longitudinal direction, such as a wire, a rod or a pipe, in the longitudinal direction. In the form, it is a round bar or a round pipe (see FIG. 5), and in Modification 1 described later, it is a square bar or a square pipe (see FIG. 8). The maximum outer diameter D3 (outer shape D3) of the coating portion 41 and the non-coating portion 42 of the article to be coated 40 is, for example, 3 mm or less, and may be as small as about 0.1 mm.

(Masking jig)
The masking jig 30 will be described with reference to FIGS. 1-2 and 5-7. FIG. 5 is a perspective view showing the masking jig 30 according to the embodiment of the present invention. FIG. 6 is an explanatory diagram showing a closed curve CC in the tubular member 31 of the embodiment. FIG. 7 is a cross-sectional view showing an end surface portion of the tubular member 31, and shows (a) without chamfering, (b) with C chamfering, and (c) with R chamfering.

As shown in FIG. 5, the masking jig 30 includes at least a tubular member 31 that holds the article to be coated 40 and a support member 32 that supports the tubular member 31. The tubular member 31 and the support member 32 are separately formed, and the support member 32 is detachably or immovably attached to the tubular member 31.

The tubular member 31 is formed in a cylindrical shape of a predetermined length by using a conductive material such as a metal pipe so that the non-coated portion 42 of the article to be coated 40 can be inserted therein. However, not limited to this, it may be formed using a semiconductive resin material in which a conductive substance such as carbon or metal is mixed.

Further, as shown in FIG. 7A, the tubular member 31 is cut along a plane orthogonal to the center of the tubular member 31, and its end surface, that is, the connection surface 31a connecting the inner surface 31b and the outer surface 31c. Has a circular ring shape. Here, the separation distance t in the direction perpendicular to the central axis of the tubular member 31 between the inner surface 31b and the outer surface 31c of the connection surface 31a is preferably 2 mm or less. In this case, the separation distance t becomes equal to the thickness of the tubular member 31.

A closed curve CC is formed at the boundary between the connecting surface 31a and the inner surface 31b (see also FIG. 6). Here, the closed curve CC literally means a closed curve in which both ends match (without both ends), and when the closed curve CC is arranged (projected) on a plane, it is divided into an inner region and an outer region, and is typically Is a circle of the present embodiment, but includes an ellipse and the like, and strictly speaking, it is not a curved line but a closed polygonal line (a figure surrounded by a finite line chain), a triangle, or a quadrangle in Modification 1 (described later) It also includes polygons such as rectangles. Further, the closed curve CC is not a line in a strict sense (that is, a line having no width), but a separation distance t in a direction perpendicular to the central axis of the tubular member 31 between the inner surface 31b and the outer surface 31c. It may be a C-chamfered surface or a R-chamfered surface (that is, a line having a small width) that is small enough for the above. However, the closed curve CC is preferably rotationally symmetric with the center of gravity as the center of rotation.

The tubular member 31 is designed according to the size and shape of the article to be coated 40 because the non-application portion 42 of the article to be coated 40 is inserted as described above, but the diameter d3 is equal to that of the article to be coated 40. It is slightly larger than the outer shape (outer diameter), and the maximum gap G between the closed curve CC and the outer diameter D4 of the non-application portion 42 (and/or the application portion 41) of the article 40 is 1 mm or less. Formed (see FIG. 6).

For example, when the outer diameter of the columnar article 40 is 3 mm, the closed curve CC of the tubular member 31 is circular, and the diameter d3 is 4 mm or less, which is larger than the outer diameter 3 mm of the article 40. The thickness t is 2 mm or less at maximum. That is, the diameter d3 of the closed curve CC is 4 mm or less, and the separation distance t in the direction perpendicular to the central axis of the tubular member 31 between the inner surface 31b and the outer surface 31c is 2 mm or less. At this time, the maximum outer diameter D3 of the tubular member 31 is 8 mm.

The end surface of the tubular member 31 may be C-chamfered so that the angle between the inner surface 31b and the connection surface 31a is 60° or less, as shown in FIG. ), R chamfering may be performed. In this way, when the connecting surface 31a is formed as the heteropolar portion 40 with respect to the liquid spray portion 20 by performing the C chamfering processing or the R chamfering processing on the end surface of the tubular member 31, the boundary between the coating portion 41 and the non-coating portion 42 is used. In the vicinity of the end surface of the tubular member 31 which is near 43, the effective separation distance tc between the inner surface 31b and the outer surface 31c in the direction perpendicular to the axis of the tubular member 31 is defined as the connecting surface between the inner surface 31b and the outer surface 31c. The apparent separation distance ta along 31a and the thickness t of the tubular member 31 can be made substantially smaller, so that when the tubular member 31 is formed of a conductive material, the coating portion The atomized particles toward 41 are less attracted to the connection surface 31a, and it is possible to prevent the application amount of the application unit 41 near the boundary 43 from decreasing.

However, the effective separation distance tc is the cylindrical member 31 from the point where the closed curve CC is formed (the point of the boundary between the connecting surface 31a and the inner surface 31b) in a cross-sectional view taken along the central axis of the cylindrical member 31. Is the distance to the inner surface 31b at the point T on the connection surface 31a which is separated by the thickness t. In other words, the effective separation distance tc is the point at which the closed curve CC is formed (the point at the boundary between the connecting surface 31a and the inner surface 31b) in the cross-sectional view of the tubular member 31 cut along the central axis. From a point (intersection point) T intersecting the connecting surface 31a to a point perpendicular to the inner surface 31b when a circle having a radius of the thickness t (separation distance t described above) of the tubular member 31 is drawn around Is the distance. Further, the effective separation distance tc is preferably 2 mm or less.

That is, in a cross-sectional view taken along the central axis of the tubular member 31, the connecting surface 31a shown in FIGS. 7B and 7C is closer to the connecting surface 31a than the separation distance t along the connecting surface 31a shown in FIG. 7A. Although the apparent separation distance ta along the line becomes large (long), the connecting surface 31a in the latter case does not extend along the plane orthogonal to the central axis of the tubular member 31 unlike the former case, and thus the closed curve Since CC extends in a direction away from the plane orthogonal to the central axis of the tubular member 31, the connecting surface 31a does not entirely serve as the different pole portion 40, and only the range of the effective separation distance tc has the different pole. It becomes part 40. As shown in FIG. 7A, the effective separation distance tc when the connection surface 31a is formed along the direction perpendicular to the central axis of the cylindrical member 31 is the separation distance t (that is, the cylindrical member). Since it is equal to the thickness t) of 31, the separation distance t in the above-described embodiment can be restated as the effective separation distance tc.

In order to make the boundary 43 between the coating portion 41 and the non-coating portion 42 of the article 40 clear, the end surface of the tubular member 31 has the end portion of the tubular member 31 orthogonal to the central axis as described above. It is preferable that the closed curve CC has a circular shape and the closed curve CC has a circular shape, but the closed curve CC may have an elliptical shape when cut with a plane that intersects the central axis at a predetermined angle. It may be such that a part of the cylindrical surface is cut out (in this case, the closed curve CC is not a single plane but a curve (in a three-dimensional space) extending over two or three planes).

The grounding means 60 may be connected to the article to be coated 40, and may be directly connected to the article to be coated 40 as shown by the solid line (i) in FIG. Alternatively, the grounding means 60 may be indirectly connected to the article to be coated 40 via the conductive portion (for example, the tubular member 31) of the masking jig 30 as shown by the one-dot chain line (ii) in FIG. it can. In this case, the grounding means 60 may be connected to the conductive parts of both the left and right masking jigs 30.

(Modification 1)
Here, the masking jig 130 of the first modification will be described. FIG. 8 is a perspective view showing a masking jig 130 of Modification 1 according to the present invention. FIG. 9: is explanatory drawing which shows the closed curve CC in the cylindrical member 131 of the modified example 1. As shown in FIG.
The masking jig 130 of the modified example 1 holds an object to be coated 140 in the shape of a square rod or a square pipe, and the tubular member 131 is the same as the masking jig 30 of the above embodiment in that it is a square pipe. Other than that, the tubular member 131 is made of a conductive material, and the other configurations such as the support member 132 are the same as those of the embodiment, and thus the description thereof will be omitted.

As shown in FIG. 9, the closed curve CC of the end of the tubular member 131 has a rectangular frame shape having an inner peripheral width of D3, an inner peripheral height of h3, and a thickness of t. Also in this case, the maximum gap G between the closed curve CC and the outer periphery of the article 140 may be designed to be 1 mm or less.

As described above, the tubular members 31, 131 of the masking jigs 30, 130 select the closed curve CC forming the predetermined gap G according to the shape of the objects 40, 140 to be coated 40. Is easier to insert. Further, the portions of the objects to be coated 40, 140 that are inserted and held in the tubular members 31, 131 and shielded from the outside become the non-application portions 42, and the portions that are not shielded by spraying the liquid by the liquid spraying portion 20. Is the application section 41.

Next, an electrostatic spraying method by the electrostatic spraying device 10 using two masking jigs 30 will be described. FIG. 10 is a schematic view showing a state in which the width of the coating portion 41 of the article to be coated 40 is changed from (a) W1 to (b) W2. The support member 32 of the masking jig 30 is fixed to a workbench (not shown).

In FIG. 10( a ), a long round bar to be coated 40 is held by two masking jigs 30 in a state where the width of the coating portion 41, that is, the interval between the tubular members 31 is W 1. .. Further, the liquid spraying section 20 is preferably arranged so as to face the coating section 41 so that the axis of the liquid spraying section 20 is in the axial direction orthogonal to the central axis of the tubular member 31, but The axis of the spraying section 20 may be inclined with respect to the central axis of the tubular member 31 within a range of about 80° to 120°.

When changing the width of the coating portion 41 to W2, one or both of the left and right masking jigs 30 are moved so that the interval between the tubular members 31 becomes W2, as shown in FIG. 10B. So that it is fixed.

The tubular member 31 of the masking jig 30 and the article to be coated 40 are not inserted in a fitted state, but are inserted and held in a state having a gap G (sliding state). Therefore, the masking jig 30 can be moved even after the object 40 to be coated is inserted, and the width of the coating section 41 can be easily changed. In addition, when the space W1 between the tubular members 31 is wider than the application range of the liquid spraying section 20, application may be performed while the liquid spraying section 20 is moved (or oscillated), or the positions may be changed. ..

As described above, the masking jigs 30 are often used in combination, but when three or more masking jigs 30 are used, the non-coating portion 42 is formed between the coating portions 41 and 41. be able to. Of course, as shown in FIGS. 5 and 7, it is also possible to use the masking jigs 30 and 130 alone, and to use only the end portion of one side of the articles 40 and 140 as the coating section 41. It is also possible to make the application portions 41 near both ends.

(Modification 2)
Next, the masking jig 230 of Modification 2 used alone will be described. FIG. 11 is a perspective view showing a masking jig 230 of Modification 2 according to the present invention.
In the above-described embodiment and the modified examples 1 and 2, the shapes of the articles to be coated 40, 140 are long articles having the same cross-sectional shape in the longitudinal direction. However, like the article to be coated 240 shown in FIG. An irregular shape such as a pin, a shaft, or a screw may be used.

The article to be coated 240 is formed of a straight portion 240a, a taper portion 240b, and a flange portion 240c. The straight portion 240a may be engraved with a male screw.

The masking jig 230 holds the article to be coated 240 such that only the straight portion 240 a of the article to be coated 240 projects from the end surface of the tubular member 231. As a result, the straight portion 240a can be the application portion 241, and the tapered portion 240b and the flange portion 240c can be the non-application portion 242. Other configurations such as the support member 232 are the same as those in the embodiment, and thus description thereof will be omitted.

As described above, the masking jig 30 according to the embodiment of the present invention includes the tubular member 31 made of a conductive material that covers the non-application portion 42 of the article 40 to which the liquid is not applied. , An inner surface 31b, an outer surface 31c, and a connection surface 31a that connects the inner surface 31b and the outer surface 31c near the end surface, and a closed curve CC is formed at the boundary between the connection surface 31a and the inner surface 31b. It is larger than the outer circumference of the non-coating portion 42, and the article 40 to be coated can be inserted therein. Thereby, the coating preparation is completed only by inserting the article to be coated 40 inside the tubular member 31, so that it is possible to provide the masking jig 30 that improves the masking workability of the article to be coated 40.

Further, the electrostatic spraying device 10 according to the embodiment of the present invention uses an electrostatic force generated by applying a voltage between the liquid spraying section 20 and a different pole section that is a different pole with respect to the liquid spraying section 20. An electrostatic spraying device (10) for separating a liquid in a charged state from a liquid spraying section (20) and spraying an atomized liquid onto an object to be coated (40), which is made of a conductive material and applies the liquid on the object to be coated (40). The masking jig 30 is provided with the tubular member 31 that covers the non-application portion 42. The tubular member 31 includes an inner surface 31b, an outer surface 31c, and a connection surface 31a that connects the inner surface 31b and the outer surface 31c near the end surface. , And a closed curve CC is formed at the boundary between the connection surface 31a and the inner surface 31b, the closed curve CC is larger than the outer circumference of the non-application portion 42, the article 40 to be inserted can be inserted, and The tubular member 31 is arranged in the axial direction orthogonal to the central axis of the tubular member 31. As a result, the liquid droplets sprayed from the liquid spraying section 20 are applied to the object to be coated 40 in the vicinity of the object to be coated 40 in the direction of the object to be coated 40 substantially at right angles to the axis of the tubular member 31. In the axial direction of the tubular member 31, there is almost no droplet intrusion in the direction in which the gap G between the article to be coated 40 and the closed curve CC extends, and between the article to be coated 40 and the tubular member 31. Even if there is a gap G in the gap G, the boundary 43 between the non-coating portion 42 and the coating portion 41 can be clearly formed.

As described above, when the tubular member 31 is made of a conductive material, if the maximum gap G between the closed curve CC and the outer periphery of the non-application portion 42 is 1 mm or less, the electrostatically atomized liquid will have this gap. It is possible to more clearly form the boundary 43 between the coating portion 41 that applies the liquid and the non-application portion 42 that does not apply the liquid without entering the G.

When the tubular member 31 is made of a conductive material, the article 40 to be coated is connected to the grounding means 60, the tubular member 31 is also connected to the grounding means 60, and the connection surface 31a is connected to the liquid spraying section 20. On the other hand, in the case of the different polarity portion 40, in the masking jig 30 having a wide connection surface 31a with an effective separation distance tc exceeding 2 mm, the liquid droplets that have reached the vicinity of the connection surface 31a of the coating portion 41 are Since it is adsorbed in the direction (side) of the connection surface 31a, it is possible that the application of the article 40 near the connection surface 31a (boundary 43) is hindered.

(Modification 3)
FIG. 12 is a perspective view showing a masking jig 330 of Modification 3 according to the present invention.
A masking jig 330 of Modification 3 is a cylindrical member 331 formed of a conductive material, an insulating protection member 333 provided on the outer periphery of the cylindrical member 331 and formed of an insulating material, And a support member 332 that supports these.

The insulating protection member 333 protects the portion of the tubular member 331 excluding the vicinity of the end surface. In other words, at least the closed curve CC is exposed to the outside. When the object 40 to be coated is held by such a masking jig 330, an electric field for electrostatic atomization is formed between the liquid spray section 20 and the object 40 and the vicinity of the end faces of the tubular member 331. However, since it is not formed between the supporting member 332 and the insulating protection member 333, the electrostatically atomized liquid does not adhere to the supporting member 332 and the insulating protection member 333. Further, the insulating protection member 333 may cover the portion of the tubular member 331 excluding the closed curve CC and the connection surface 331 a, that is, the entire outer peripheral surface of the tubular member 331.

When the masking jig 330 is applied to the square rod-shaped object 140, the tubular member 331 and the insulating protection member 333 may be formed in a square pipe shape.

(Modification 4)
In the masking jigs 30, 130, 230 of the above-described embodiment and the modified examples 1 and 2, the tubular members 31, 131, 231 were formed by using a conductive material, but the tubular members were formed by using an insulating material. It is also applicable when forming the members 31, 131, and 231. In the modified example 4, the materials for forming the tubular members 31, 131, and 231 are different, and the shapes and structures are not different, and therefore the description of each configuration is omitted.

For example, if the connecting surface 31a is charged without forming the connecting surface 31a as the different pole portion 40 with respect to the liquid spraying portion 20 by forming the tubular member 31 using an insulating material, the connecting portion 31a and the coating portion 41 are formed. The effective separation distance tc between the inner surface 31b and the outer surface 31c can be substantially reduced in the vicinity of the end surface of the tubular member 31, which is near the boundary 43 with the non-application portion 42, and thereby the fog toward the application portion 41. It is possible to prevent the atomized particles from moving away from the connection surface 31a, and it is possible to prevent the application amount of the application portion 41 near the boundary 43 from decreasing.

In this case, unlike the embodiment, the maximum gap G between the closed curve CC and the outer periphery of the non-application portion 42 can be increased to 2 mm or less. As described above, even if the maximum gap G between the closed curve CC and the outer periphery of the non-application portion 42 becomes 2 mm, the electrostatically atomized liquid does not enter the gap G, and the liquid in the article to be coated 40 does not enter. It is possible to more clearly form the boundary 43 between the application portion 41 that applies the liquid and the non-application portion 42 that does not apply the liquid.

However, in the case where the tubular member 31 is formed of an insulating material and has a wide connection surface 31a such that the effective separation distance tc exceeds 2 mm, the liquid droplets that have reached the vicinity of the connection surface 31a of the coating unit 41 will not contact the connection surface 31a. Due to the electrostatic charge, an electrostatic force is applied in a direction (side) away from the connection surface 31a and is pressed, so that the application of the article 40 near the connection surface 31a may be hindered. Further, since the electrostatic force received by the droplets from the connection surface 31a changes depending on the charged state of the connection surface 31a, the masking may become unstable due to the humidity of the surrounding environment.

In the above-described embodiment, the inner surface 31b and the outer surface 31c of the tubular member 31 are parallel to each other, but the inner surface 31b and the outer surface 31c do not necessarily have to be parallel to each other. The thickness may be thicker or thinner, or may be thicker or thinner stepwise. The same applies to the tubular members 131, 231, 331 of Modifications 1 to 4.

In the above-described embodiments and modified examples, the articles to be coated 40, 140, 240 are long or short articles having a standard length, but the wire wound around the core as the article to be coated is unwound and intermittently wound. Alternatively, an infinite length long product (substantially endless long product) supplied to the above may be applied.

In the above-described embodiment and modified example, the different-polarity portion 40 is the article to be coated 40, but an additional different-polarity portion 40 for promoting the separation of the liquid in the charged state is provided in the vicinity of the liquid nozzle 22 of the liquid spraying portion 20. It may be provided.

As described above, the present invention is not limited to the specific embodiments and modified examples, and those appropriately modified and improved are also included in the technical scope of the present invention. It will be apparent to those skilled in the art from the description of the claims.

DESCRIPTION OF SYMBOLS 10 Electrostatic spraying device 20 Liquid spraying part 21 Body part, 21a Liquid supply port, 21b Liquid flow path, 21c Hole part, 21d Rear end opening part, 21e Female screw structure 22 Liquid nozzle, 22a Tip outer peripheral edge, 22b Opening part 23 Mandrel, 23a knob portion, 23b electric wiring connection portion, 23c male screw structure, 23d tip surface 24 sealing member 30 masking jig 31 tubular member, 31a connecting surface, 31b inner surface, 31c outer surface, CC closed curve, D3 outer diameter (width ), d3 diameter, tc effective separation distance, t separation distance (width or thickness), ta apparent separation distance, h3 height, T point 32 support member 40 different pole portion (coated object), D4 outer diameter 41 coating portion 42 Non-application part 43 Boundary 130,230,330 Masking jig 131,231,331 Cylindrical member, 131a, 231a, 331a Connection surface 132,232,332 Support member 333 Insulation protection member 140,240 Coated object 240a Straight part, 240b Tapered part, 240c Flange part 241 Coating part 242 Non-coating part 50 Voltage applying means 60 Grounding means TC Taylor cone G Gap

Claims (10)

Liquid is sprayed from the liquid spraying section by an electrostatic force generated by applying a voltage between the liquid spraying section and a different polarity section having a different polarity with respect to the liquid spraying section, and is applied to an object to be coated. A masking jig used in an electrostatic spraying device for spraying an atomized liquid,
A tubular member that covers a non-application portion of the article to which the liquid is not applied,
The tubular member has an inner surface, an outer surface, and a connecting surface that connects the inner surface and the outer surface in the vicinity of the end surface, and a closed curve is formed at a boundary portion between the connecting surface and the inner surface.
The closed curve is larger than the outer periphery of the non-application portion, and the article to be coated can be inserted.
A masking jig characterized by that. The tubular member has a portion formed of an insulating material,
The masking jig according to claim 1, wherein: The maximum gap between the closed curve and the outer periphery of the non-application portion is 2 mm or less.
The masking jig according to claim 2, wherein: The tubular member has a portion formed of a conductive material or a semiconductive material,
The masking jig according to claim 1, wherein: The maximum gap between the closed curve and the outer periphery of the non-application portion is 1 mm or less.
The masking jig according to claim 4, wherein The tubular member is covered with an insulating material except for the connection surface.
The masking jig according to claim 4, wherein the masking jig is a masking jig. In a cross-sectional view along the axis of the tubular member, the distance from the point where the closed curve is formed to the inner surface at a point on the connection surface that is separated by the thickness of the tubular member is 2 mm or less,
7. The masking jig according to claim 1, wherein the masking jig is a masking jig. The article to be coated is a long object having the same sectional shape in the longitudinal direction,
The masking jig according to claim 1, wherein the masking jig is a masking jig. The article to be coated has a maximum outer diameter of the non-application portion of 3 mm or less,
9. The masking jig according to claim 1, wherein the masking jig is a masking jig. Liquid is sprayed from the liquid spraying section by an electrostatic force generated by applying a voltage between the liquid spraying section and a different polarity section having a different polarity with respect to the liquid spraying section, and is applied to an object to be coated. An electrostatic spraying device for spraying an atomized liquid,
A masking jig having a tubular member for covering a non-application portion of the article to be coated with no liquid,
The tubular member has an inner surface, an outer surface, and a connecting surface that connects the inner surface and the outer surface in the vicinity of an end surface, and a closed curve is formed at a boundary portion between the connecting surface and the inner surface.
The closed curve is larger than the outer periphery of the non-application portion, the object to be coated can be inserted,
The liquid spray section is arranged in an axial direction orthogonal to the central axis of the tubular member,
An electrostatic spraying device characterized by the above.

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