KR100436623B1 - Method for electrostatic coating a metallic cylindrical body - Google Patents

Abstract

In the electrostatic coating method of a metal cylindrical body having a substantially cylindrical shape formed by laminating metal plates, an electrode shaft 18 serving as a supporting rod is inserted into the shaft hole 2 of the metal cylinder CL, and the shaft hole 2 The metal cylindrical body CL is supported by making the inner peripheral surface of the bottom face contact along the axial direction. In this state, the metal cylinder CL is disposed above the flow tank, and electrostatic coating is performed while rotating the metal cylinder CL. Thereby, the resin powder can be uniformly adhered to the surface of the metal cylinder CL. Subsequently, the adhered resin powder is heat-sealed to form a coating film. At this time, since the resin powder does not adhere to the portion where the supporting rod of the inner circumference of the metal cylinder abuts, the unpainted portion becomes a passage for introducing air between the laminated plates expanded by heating, thereby preventing the generation of holes on the surface of the coating film. . The liquid crystal composition of the room temperature curing type is applied to the inner circumferential portion of the electrode shaft 18 which is in contact with the uncoated, and preferably, the gas is sprayed on the coated surface to uniformly expand the liquid resin composition, and then harden. To form a coating film.

Description

Electrostatic coating method of metal cylinder {METHOD FOR ELECTROSTATIC COATING A METALLIC CYLINDRICAL BODY}

An object of the present invention is a method of electrostatic coating of a metal cylinder having a substantially cylindrical shape formed by laminating a metal plate, such as a rotor core or a stator core, with no pinhole or the like in the coating film, and the outer circumference and the inner circumference are uniform. It is to provide a way to paint.

The present invention relates to an electrostatic coating method of a metal cylindrical body having a substantially cylindrical shape formed by laminating metal plates, and in particular, an electrostatic coating method suitable for insulating coating of a rotor core or a stator core used in a rotating electric machine such as a motor or a generator. It is about.

The rotor core or stator core used for rotating electric machines such as motors and generators is formed by stacking a plurality of magnetic metal pieces made of silicon steel sheets, and in the case of rotor iron cores, slots for inserting coils are formed outside. In the case of a stator core, a slot for inserting a coil is formed inside.

An example of the rotor core is shown in FIG. The rotor core 1 is formed by stacking a plurality of magnetic metal pieces 60, has a shaft hole 2 in the center, and slots 4 along the axial direction of the outer periphery 3 in the circumferential direction. It is formed at intervals, and between the slots 4 forms a protrusion 61 for winding the coil. In the figure, 47 indicates a corner portion of the end surface inner circumference.

Electrodeposition coating and electrostatic coating are known as a method of coating the metal cylinder formed by laminating | stacking a metal plate like this rotor core. However, electrodeposition coating has a problem that the equipment is large, the maintenance of the machine is also a big problem, and the production cost is generally expensive.

On the other hand, the electrostatic coating is formed by applying a resin powder to the flow tank by using an electrostatic coating device having a flow tank in which an upper surface is opened and a porous plate disposed on a lower surface thereof, an electrode provided on the porous plate, and a pressure equalizing chamber surrounding a space below the flow tank. And supplying pressure air to the equalization chamber and ejecting it through the porous plate, fluidizing the resin powder in the flow chamber, and imparting positive or negative static electricity to the electrode, thereby charging the resin powder and opposing the electrode. The coated object to which static electricity is applied is supported on the upper side of the flow tank, and the resin powder is attached to the surface of the coated object, followed by heating the coated object to fuse the adhered resin powder to form a coating film.

However, when the front coating was performed by the electrostatic coating on the metal cylinder formed by laminating the metal plates as described above, there were the following problems.

(1) Since the resin powder is fused and heated to form a coating film, the air of the laminated metal sheet expands, resulting in the resulting traces of expanded air on the surface of the coating film. none.

(2) The resin powder is thickly attached to the outer circumference (3) and the end face (5), but the resin powder is not sufficiently attached to the inner circumference of the shaft hole (2) or the slot (4), and there is a gap in the final coating thickness. .

In order to achieve the above object, the electrostatic coating method of the present invention is a method of electrostatic coating of a metal cylindrical body having a substantially cylindrical shape formed by laminating metal plates, wherein the supporting rod is inserted into the shaft hole of the metal cylindrical body, and the shaft hole is formed. By contacting the inner circumferential surface along the axial direction, the metal cylinder is supported, the metal cylinder is placed above the flow tank of the resin powder, and the resin powder is fixed on the surface of the metal cylinder while the metal cylinder is rotated. After completely adhering, the first coating step of forming a coating film by heat-sealing the attached resin powder, and applying a room temperature-curable resin composition to a portion where the support rod of the inner circumference of the metal cylinder abuts to be unpainted. It characterized by including a second coating step of forming a.

According to the present invention, when the metal cylinder is electrostatically coated in the first coating step, the resin powder can be uniformly attached by rotating the metal cylinder. In addition, since the resin powder does not adhere to the portion where the supporting rod of the inner circumference of the metal cylinder abuts, air passages between the laminated plates in which the unpainted portion expands by heating are formed when the attached resin powder is heat-sealed to form a coating film. It is possible to prevent the generation of holes on the coating film surface.

Next, as a second coating step, by coating a resin composition of a room temperature curing type on an uncoated portion of the inner circumference of the metal cylinder and curing at room temperature, a coating film can be formed around all of the metal cylinder. .

1 is a front sectional view of an electrostatic coating apparatus for use in the first embodiment of the electrostatic coating method of the present invention.

FIG. 2 is a perspective view of FIG. 1.

3 is a front sectional view of the electrostatic coating apparatus used in the second embodiment of the electrostatic coating method of the present invention.

4 is an x-ray arrow view of FIG.

5 is a perspective view of FIG. 3.

6 is a front sectional view of the electrostatic coating apparatus used for the third embodiment of the electrostatic coating method of the present invention.

7 is a perspective view showing a fourth embodiment of the electrostatic coating method of the present invention.

8 is a front cross-sectional view of the electrostatic coating apparatus used for the fifth embodiment of the electrostatic coating method of the present invention.

9 is a front sectional view of the electrostatic coating apparatus used for the sixth embodiment of the electrostatic coating method of the invention.

10 is a schematic illustration showing an example of a second coating step of the electrostatic coating method of the invention.

Fig. 11 is an enlarged sectional view showing the main parts of a state in which a resin composition is applied in a second coating step of the electrostatic coating method of the present invention.

12 is a plan view showing an example of the case where a cylindrical body having a groove is coated on the inner circumference in the second coating step of the electrostatic coating method of the invention.

Fig. 13 is a perspective view showing a rotor core as an example of a metal cylinder formed by laminating metal plates.

Fig. 14 is a cross-sectional view showing a state where a liquid resin of room temperature hardening type is applied to the inner circumference of a metal cylinder by a conventional method.

Fig. 15 is a cross-sectional view showing a state where a liquid resin of a room temperature hardening type is applied by a conventional method on the inner circumference of a metal cylinder having a groove on the inner circumference.

It will be described in more detail with reference to a preferred embodiment of the present invention.

In the electrostatic coating method of the present invention, as described above, first, as the first coating step, a support rod is inserted into the shaft hole of the metal cylinder, and the support rod is brought into contact with the inner circumferential surface of the shaft hole in the axial direction so as to contact the metal cylinder. And the metal cylinder is placed above the flow tank of the resin powder in this state, and the resin powder is electrostatically attached to the surface of the metal cylinder while the metal cylinder is rotated, and then the attached resin powder is heat-sealed. To form a coating film. Next, as a second coating step, a coating film is formed by applying a room temperature-curable resin composition to a portion where the supporting rod of the inner circumference of the metal cylinder abuts and is unpainted.

According to a preferred embodiment of the present invention, when the metal cylinder is supported above the flow tank of the resin powder in the first coating process, an annular baffle plate is arranged at a predetermined distance from the end face of the metal cylinder. The resin powder is attached while rotating the metal cylinder.

By arranging the baffle plate, what flows in between the end face of the metal cylinder and the baffle plate among the resin powders suspended from the flow tank is attached to the end face of the metal cylinder, but it flows outside the baffle plate. Attachment to the end face is prevented by the plate. On the other hand, in the shaft hole of the metal cylinder, even if it flows between the end face of the metal cylinder and the baffle plate and flows outside the baffle plate, it flows in through the hole in the center of the baffle plate. This can increase the amount of resin powder flowing into the shaft hole. Further, among the resin powders, the flow between the end face of the metal cylinder and the baffle plate is prevented from scattering around by the baffle plate, and therefore easily enters the slot from the end face side of the metal cylinder. As a result, the thickness of the resin powder adhering to the end surface and outer periphery of a metal cylinder, and the thickness of the resin powder adhering to a shaft hole or slot inner periphery can be averaged, and the thickness of the coating film finally obtained can be made more uniform.

According to a further preferred embodiment of the present invention, a cover plate having a cross-shaped opening is provided on the upper surface of the flow tank, and when the metal cylinder is supported above the opening, the axial direction of the metal cylinder is determined. It is arranged toward one direction of the cross-shaped opening, the portion along the axial direction of the metal cylinder of the opening has a width shorter than the outer diameter of the metal cylinder, has a length longer than the interval of the baffle plate, The portion of the opening along the axial direction and the perpendicular direction of the metal cylindrical body has a width shorter than the axial length of the metal cylindrical body and a length longer than the outer diameter.

According to this embodiment, since the portion along the axial direction of the metal cylindrical body of the cross-shaped opening extends to the outside of the baffle plate, the resin powder also flows to the outside of the baffle plate, and the resin powder is formed on the baffle plate. Since it flows into the shaft hole of the metal cylinder through the center hole, the amount of resin powder adhering around the shaft hole can be relatively increased. In addition, since the portion along the axial direction of the metal cylindrical body of the cross-shaped opening has a width shorter than the outer diameter of the metal cylindrical body, for example, when a metal cylindrical body having a slot on the outer periphery is used as shown in FIG. By reducing the amount of resin powder rising at an angle that is difficult to enter into the slot of the metal cylinder, the amount of resin powder rising at an angle that is easy to enter into the slot of the metal cylinder is increased relatively, and the outer peripheral surface and the slot of the metal cylinder The amount of resin powder adhering to the inner surface can be made more uniform. In addition, since the portion along the axial direction and the perpendicular direction of the metal cylindrical body of the cross-shaped opening is shorter than the axial length of the metal cylindrical body and is longer than the outer diameter, it flows near the end surface of the metal cylindrical body. By reducing the amount of resin powder relatively, the amount of resin powder adhering to the surface of the metal cylinder can be made more uniform.

According to a further preferred embodiment of the present invention, the metal cylinder is disposed on the upper side of the flow tank, and suction means is further provided on the upper side and / or the side of the metal cylinder, and the resin powder is provided by the suction means. To form a flow.

According to this embodiment, by forming the flow of the resin powder by the suction means, the resin powder can be easily attached to the desired portion. Particularly, in the case where the suction means is provided on the upper side and the side of the metal cylinder, when the upper suction means is operated, a strong flow is directed upward, so that the resin powder is easily introduced into the slot and the end face The resin powder adhering to can be made more uniform. In addition, when the side suction means is operated, a flow directed in the horizontal direction can be formed, whereby the resin powder can be easily introduced into the shaft hole or the slot.

According to a further preferred embodiment of the present invention, the scraping member is disposed close to the outer circumference of the metal cylinder, and the thickness of the resin powder attached to the outer circumference of the metal cylinder is adjusted by the scraping member. .

Since the amount of resin powder adhering to the outer circumference of the metal cylinder tends to be formed relatively thick even when various means described above are taken, the excess portion of the resin powder attached to the outer circumference by arranging the scraping member is disposed. By forcibly scraping off, the adhesion amount of the resin powder can be made more uniform.

In a further preferred embodiment of the present invention, in the second step, by applying the liquid resin composition of the normal temperature hardening type to the inner circumference of the metal cylinder which the support rod is in contact with the uncoated, the inner circumference of the metal cylinder By blowing out the gas, the liquid resin composition attached to the inner circumference of the metal cylinder is uniformly stretched and spread, and then the liquid resin composition is cured to form a coating film.

According to this embodiment, the gas is blown out to spread the liquid resin composition uniformly, thereby preventing the flow of paint and unevenness, thereby forming a coating film having a uniform thickness.

According to a further preferred embodiment of the present invention, in the second coating step, a pair of jig having an opening suitable for the inner circumference of the metal cylinder, by clamping both end surfaces of the metal cylinder to support the metal cylinder While rotating the metal cylinder together with the jig, the liquid resin composition is applied to the inner circumference of the metal cylinder and the gas is blown out to the inner circumference of the metal cylinder.

This prevents the attachment of the extra paint to the end face of the metal cylinder, and the upper jig secures the film thickness of each inner circumference of the upper end face of the metal cylinder, and the lower jig is the lower inner circumference of the metal cylinder. It is effective in eliminating liquid pools.

Further, using the UV-curable resin composition as the liquid resin composition, the UV-curable resin composition is applied to the uncoated portion of the inner circumference of the metal cylinder, and the gas is blown out, and then on the inner circumference of the metal cylinder. It is preferable to harden the said ultraviolet curing resin composition by irradiating an ultraviolet-ray.

Thereby, the heating of the resin does not require heating, and the resin composition coated on the inner circumference of the metal cylinder can be instantaneously and uniformly cured.

In addition, the metal cylinder is preferably a stator core or a rotor core used in a rotary electric machine. Since these iron cores are made of a laminate of metal plates and require more complete insulation and rust prevention, the advantage of applying the method of the present invention is particularly great.

1 and 2 show a first embodiment of the electrostatic coating method of the present invention, FIG. 1 is a front sectional view of an electrostatic coating apparatus used in the same method, and FIG. 2 is a principal part perspective view of FIG.

The electrostatic coating apparatus includes a frame member 11 having an upper surface opened, a porous plate 13 covering the lower surface thereof, and a housing 14 disposed on the lower surface of the porous plate 13. 11) and the porous plate 13, the flow tank 12 to which the resin powder P is supplied and filled is formed, and the pressure equalizing chamber 15 is formed by the porous plate 13 and the housing 14. It is. At the side of the pressure equalizing chamber 15, an air supply port 16 for introducing the pressure air AR into the pressure equalizing chamber 15 is provided. A plurality of electrodes 17 are provided on the porous plate 13, and positive or negative static electricity is applied to the resin powder P.

The metal cylindrical body CL (specifically, the laminated iron core 1) to be coated is disposed on the upper side of the flow tank 12, and its axis is horizontally oriented, and the pair of electrode shafts 18 are axial holes 2. Is inserted into the inner circumference of the support. The electrode shaft 18 is applied to a rotating body 19 that is applied with a voltage opposite to that of the electrode 17 of the porous plate 13 and rotates by a drive source (not shown). The electrode shaft 18 abuts against the inner circumference of the shaft hole 2 of the metal cylinder CL in a line shape along the axial direction, and forms a supporting rod in the present invention.

Further, in order to regulate the flow of the resin powder P from the flow tank 12 to the left and right end surfaces 5 and 5 'of the metal cylinder CL, the baffle plates 20 and 21 have the left and right end surfaces. In (5, 5 '), it arrange | positions at some distance, for example several mm, in the direction of the axial center C. The baffle plates 20 and 21 form an annular shape with holes 20b and 21b at the center, and have tapered holes 20a and 21a through which the electrode shaft 18 passes.

The electrode shaft 18 has a stepped portion 18a to which the end face of the metal cylinder CL interlocks, a stepped portion 18b to which the tapered hole 20a of the baffle plate 20 interlocks, and a baffle plate ( 21 has a stepped portion 18c to which the tapered holes 21a of 21 are interlocked, and movement of the metal cylindrical body CL and the baffle plates 20 and 21 in the axial direction is restricted by these stepped portions. .

In the above configuration, the pressure air AR is supplied from the air supply port 16 to the flow tank 12 through the porous plate 13, and the pressure air AR is introduced into the pressure equalizing chamber 15 to provide a porous plate ( By blowing through 13), the resin powder P in the flow tank 12 is fluidized. In addition, the rotating body 19 is rotated to gently rotate the metal cylinder CL together with the electrode shaft 18.

When a predetermined voltage is applied between the electrode 17 and the electrode shaft 18 in this state, the resin powder P is positively or negatively charged by the electrode 17 and reversed through the electrode shaft 18. It is electrostatically attached to the metal cylinder CL to which a voltage is applied.

In this case, the resin powder P, which rises from the flow tank 12 and flows upward, is attached to the outer periphery 3 and the slot 4 of the metal cylinder CL, and the metal cylinder CL. Of the left and right end surfaces 5, 5 'and baffle plates 20, 21, and attached to the left and right end surfaces 5, 5', ③ shaft hole 2 of metal cylinder CL. To be attached to the inner circumference and the like.

However, by providing the baffle plates 20 and 21, the resin powder P flowing outside the baffle plates 20 and 21 can be attached to the left and right end surfaces 5 and 5 'of the metal cylinder CL. Therefore, the amount of the resin powder P adhering to the left and right end surfaces 5, 5 'is smaller than when the baffle plates 20, 21 are not provided.

On the other hand, in the shaft hole 2 of the metal cylindrical body CL, not only flowed into the clearance gap between the left and right end surfaces 5 and 5 'of the metal cylindrical body CL, and the baffle plates 20 and 21, It also flows outside the baffle plates 20 and 21 and passes through the holes 20b and 21b of the baffle plates 20 and 21, so that it does not decrease much compared to the case where the baffle plates 20 and 21 are not provided. .

In addition, part of the resin powder P introduced into the gap between the left and right end surfaces 5, 5 'of the metal cylinder CL and the baffle plates 20, 21 is reflected by the inner surface of the baffle plates 20, 21. Then, it enters into the slot 4 from the end surface side of the metal cylinder CL.

As a result, as compared with the case where the baffle plates 20 and 21 are not provided, the amount of the resin powder P entering the shaft hole 2 and the slot 4 is relatively increased, and the surface of the metal cylinder CL is increased. It becomes possible to make resin powder P adhere | attach more uniformly.

In this way, after the resin powder P is attached to the surface of the metal cylinder CL, the metal cylinder CL is removed from the electrode shaft 18, or the metal cylinder CL is removed from the electrode shaft 18. While being held in a high temperature furnace, the mixture is heated in a high frequency heating furnace or a hot air drying furnace, and the resin powder P is welded to form a coating film.

Since the metal cylindrical body CL is supported by the electrode shaft 18 inserted in the shaft hole 2, the resin powder P is attached to the part of the shaft hole 2 which contacts this electrode shaft 18. As shown in FIG. Do not attach In addition, although the air between the laminated steel sheets expands and tries to flow out during the heating, the expanded air is released from the portion where the resin powder P is not attached, thereby preventing pinholes or the like from occurring in the coating film. Can be. In addition, the surface of the electrode shaft 18 abutting the coating film is hardened, for example, by applying a hardening resin of room temperature type, such as an ultraviolet curable resin, so that a problem such as pinholes due to the expansion of air between the laminated steel sheets does not occur. A coating film can be formed in the whole.

In this invention, well-known coating powders, such as polyester type and an epoxy type, can be used as resin powder (P).

3 to 5 show a second embodiment of the electrostatic coating method according to the present invention, FIG. 3 is a front sectional view of the electrostatic coating apparatus used in the same method, and FIG. 4 is an arrow view of the XX line of FIG. 5 is a principal part perspective view of FIG. 3. In addition, the same code | symbol is attached | subjected to the substantially same part as the said 1st Example, and the description is abbreviate | omitted.

Also in the second embodiment, as in the first embodiment, the metal cylinder CL is supported by a pair of electrode shafts 18, and the left and right end surfaces 5, 5 'of the metal cylinder CL are supported. In the vicinity, baffle plates 20 and 21 for guiding the flow of the resin powder P are provided.

The feature of the second embodiment lies in that the cover plate 31 having an opening H forming a cross shape is arranged on the upper surface of the flow tank 12 at a plane view. This opening portion H has a portion A along the axial direction of the metal cylinder CL and a portion B along the axial direction and at right angles. The portion A along the axial direction has a width W1 smaller than the outer diameter W of the metal cylinder CL, and the length L1 is smaller than the excretion intervals LL of the left and right baffle plates 20 and 21. long. The width B2 of the portion B along the axial direction and the right angle direction is shorter than the axial length L of the metal cylinder CL, and the length L2 is smaller than the outer diameter W of the metal cylinder CL. long.

Therefore, according to this second embodiment, since the portion A along the axial direction of the metal cylinder CL of the cross-shaped opening H extends outward of the baffle plates 20 and 21, The resin powder P also flows outside the baffle plates 20 and 21, and the resin powder P passes through the metal holes CL through the holes 20b and 21b in the center of the baffle plates 20 and 21. Since it flows into the axial hole 2 of the axial hole 2, the adhesion amount of the resin powder P of the inner periphery of the axial hole 2 can be increased relatively.

In addition, since the portion A along the axial direction of the metal cylindrical body CL of the cross-shaped opening portion H has a width shorter than the outer diameter W of the metal cylindrical body CL, the metal cylindrical body ( The amount of resin powder rising at an angle that is hard to enter the slot 4 of CL (the more difficult it is to enter the slot 4 as it moves away from the center of the metal cylinder CL) is reduced, and the slot of the metal cylinder CL is reduced. The amount of resin powder which rises at an angle which is easy to enter (4) is made relatively large, and the amount of resin powder adhering to the outer circumference 3 and the slot 4 of the metal cylinder CL can be made more uniform.

The width W2 of the portion B along the axial direction and the right angle direction of the metal cylindrical body CL of the cross-shaped opening portion H is shorter than the axial length L of the metal cylindrical body CL, and the shaft Since the length L2 of the portion B along the direction perpendicular to the direction is longer than the outer diameter W of the metal cylinder CL, it is near the left and right end surfaces 5, 5 'of the metal cylinder CL. The amount of resin powder P flowing into the resin powder is relatively small, and the amount of resin powder adhering to the left and right end surfaces 5, 5 'of the metal cylinder CL is reduced, so that the resin powder P as a whole The adhesion amount can be made more uniform.

In this second embodiment, the metal cylindrical body CL was tested using a laminated iron core having an outer diameter W of 20.3 mm, an axis length L of 8.8 mm, and an inner diameter of the shaft hole 2 of 15 mm. The thickness of the coating film is 25 to 30 µm in the shaft hole 2, 40 µm in the outer circumferential portion 3, 36-40 µm in the slot 4, and 50 µm in the left and right end surfaces 5 and 5 '. The coating film thickness inside the shaft hole 2 or the slot 4, which P is hard to attach, is sufficiently uniform as compared with the conventional electrostatic coating method without the baffle plate 20 or the cover plate 31. It turned out.

6 is a front sectional view of the electrostatic coating apparatus used for the third embodiment of the electrostatic coating method according to the present invention. In addition, substantially the same part as 1st and 2nd Example is attached | subjected with the same code | symbol, and the description is abbreviate | omitted.

Also in the third embodiment, as in the second embodiment, the metal cylinder CL is supported by a pair of electrode shafts 18, and the left and right end surfaces 5, 5 'of the metal cylinder CL are supported. B) baffles plates 20 and 21 for inducing the flow of the resin powder P are installed in the vicinity thereof, and a cover plate 31 having a cross-shaped opening portion H is disposed on the surface of the flow tank 2. It is.

The feature of the third embodiment is that the suction means 32, 33 for forcibly forming the flow of the resin powder P from the flow tank 12 toward the metal cylinder CL in the desired direction is provided. . One suction means 32 is disposed above the metal cylinder CL, and the other suction means 33 is disposed on one side of the metal cylinder CL. In addition, in this embodiment, the suction means 32, 33 consists of a suction cylinder connected to the suction pump which is not shown in figure, and which suction means 32 and 33 are selectively selected by the switching valve arrange | positioned in a suction cylinder. It is supposed to work.

Therefore, when the suction means 32 on the upper side of the metal cylinder CL is operated, a strong flow is formed upward from the flow tank 12, and the slot 4 of the lower surface of the metal cylinder CL is formed. Resin powder (P) is easily introduced into the resin, increases the amount of resin powder (P) attached to the slot (4), and passes near the left and right end surfaces (5, 5 ') of the metal cylinder (CL). By increasing the flow velocity of the resin powder P, the amount of the resin powder P adhered to the left and right end surfaces 5, 5 'can be reduced, and the thickness can be adhered to a uniform thickness.

Moreover, when the suction means 33 in the side part of the metal cylinder CL is operated, the resin powder P raised from the flow tank 12 will flow to one side along the axial direction of the metal cylinder CL. Therefore, the resin powder P easily flows into the shaft hole 2 or the slot 4, so that the amount of the resin powder P adhered to the shaft hole 2 or the slot 4 can be increased. In this case, the metal cylinder CL is moved relative to the flow tank 12, or the opening portion H of the cover plate 31 is moved to move the position of the metal cylinder CL. By moving relatively in the direction of the suction means 33 directly above the bath 12, the flow can be more effectively formed.

7 is a perspective view showing a fourth embodiment of the electrostatic coating method of the present invention. In addition, the same code | symbol is attached | subjected to the substantially same part as 1st-3rd Example, and the description is abbreviate | omitted.

The fourth embodiment is characterized in that the scraping member 34 of the resin powder P is provided close to the outer circumference 3 of the metal cylinder CL supported by the pair of electrode shafts 18. Is in. As the scraping member 34, a spatula-shaped plate made of synthetic resin is adopted in this embodiment, but it may be a roller or a brush. The gap T between the scraping member 34 and the outer circumference 3 of the metal cylinder CL may be appropriately set in accordance with the desired thickness of the resin powder P, but is usually about several times the desired coating film thickness. Is preferred.

In this embodiment, the excess resin powder P is scratched off by the scraping member 34 when the excessively thick resin powder P adheres to the outer circumference 3 of the metal cylinder CL. The resin powder P having an appropriate thickness can always be attached to the outer circumference 3 of the metal cylinder CL. In this embodiment, the tip edge 34a of the scraping member 34 is brought into contact with the outer circumference of the baffle plates 20 and 21, so that the outer circumference of the scraping member 34 and the metal cylinder CL is provided. The gap T with (3) is prescribed.

8 is a front sectional view of the electrostatic coating apparatus used for the fifth embodiment of the electrostatic coating method according to the present invention. In addition, the same reference numerals are given to substantially the same parts as the first to fourth embodiments, and description thereof will be omitted.

As a feature of this fifth embodiment, as shown in Fig. 3, the metal cylinder CL is supported such that its axial direction is in the horizontal direction, and the resin powder P is attached in the same manner as in the above embodiment. Then, as shown in FIG. 8, the support angle is changed so that the metal cylinder CL may face the axial direction vertically.

That is, when the metal cylindrical body CL is supported so that the axial direction may become a vertical direction, the resin powder P which rises from the flow tank 12 will be the axial hole 2 and the slot ( 4) It is easy to enter, and the thickness of the coating film in the axial hole 2 and the slot 4 can be made thicker.

9 to 12 show a sixth embodiment of the electrostatic coating method of the present invention, FIG. 9 is a front sectional view of an electrostatic coating apparatus used in the same method, and FIG. 10 is a schematic diagram showing a second coating process of the same method. Explanatory drawing and FIG. 11 is an enlarged sectional view of the principal part which shows the state which apply | coated the resin composition in the 2nd coating process. In addition, substantially the same part as a 1st thru | or 5th embodiment attaches | subjects the same code | symbol, and abbreviate | omits the description.

In the sixth embodiment, the metal cylindrical body CL to be coated is supported by an electrode shaft 18 suitable for the inner circumference of the shaft hole 2. One end surface of the metal cylindrical body CL interlocks with the stepped portion 18d of the electrode shaft 18, and the other end surface is pressed by the cap 22 to be fixed to the electrode shaft 18. It is. In this embodiment, since the shaft hole of the metal cylinder CL is blocked by the electrode shaft 18 and the cap 22, and the resin powder hardly enters, the baffle plates as in the first to fifth embodiments described above. Do not need.

As described above, the resin powder P is attached while the metal cylinder is rotated. At this time, the scraping member of the resin powder is provided in close proximity to the outer circumference of the metal cylinder CL, and the metal cylinder ( By scraping off the excess resin powder P attached to the outer circumference of the CL, the resin powder P having an appropriate thickness may always be attached to the outer circumference of the metal cylinder CL. In this manner, after the resin powder P is attached to the surface of the metal cylinder CL, the metal cylinder CL is removed from the electrode shaft 18, or the metal cylinder CL is removed from the electrode shaft 18. It is put in a high frequency heating furnace or a hot air drying furnace and heated, and the resin powder P is welded to form a coating film.

Next, the second coating step will be described. In this step, the liquid resin composition of the normal temperature hardening type is applied to the inner circumferential portion of the shaft hole which is not coated by the support rod in the first coating step.

At this time, when the viscosity of the liquid resin composition 42 of the room temperature curing type is low, as shown in FIG. 14, the film thickness of the inner circumference 47 of the upper end surface of the metal cylinder CL becomes thin, or the liquid pools in the lower portion of the inner circumference. If the groove 51 or the like is formed in the inner circumference 50 of the metal cylinder CL as shown in Fig. 15 and the viscosity is high on the contrary, the groove is crushed and cannot be painted uniformly.

Therefore, as shown in Fig. 10A, both end faces of the metal cylinder CL, in which the coating film 43 is formed at portions other than the inner circumference of the shaft hole in the first coating process, are formed on the metal cylinder CL. Is supported by a pair of jig (41a, 41b) having an opening suitable for the inner circumference of the c), and the paint is supplied to the shaft hole of the metal cylinder (CL) while rotating the metal cylinder (CL) together with the jig. The nozzle 40 is inserted to apply a liquid resin composition of normal temperature curing type, and in this embodiment, a liquid resin composition 42 of ultraviolet curing type to its inner circumference. In addition, the metal cylinder CL may be fixed and the paint supply nozzle 40 may be rotated.

Then, as shown in FIG. 10 (b), a gas, such as air or nitrogen, is blown out from the gas supply nozzle 44 to the inner circumference of the metal cylinder CL, so that the ultraviolet-curable liquid resin composition 42 is circumscribed. Stretch evenly on face.

At this time, by clamping with a pair of jig (41a, 41b) having an opening suitable for the inner circumference of the metal cylinder (CL), as shown in Figure 11, the liquid resin composition on the end surface of the metal cylinder (CL) (42) can be prevented from being attached extraly. Moreover, the film thickness of the inner peripheral part 47 of the upper end surface of the metal cylinder CL is ensured by the upper jig 41a, and the film thickness of the inner peripheral lower part of the metal cylinder CL is ensured by the lower jig 41b. The effect of eliminating liquid pools is brought about.

Further, by gas is blown out from the gas supply nozzle 44 to the inner circumference of the metal cylinder CL, as shown in FIG. 12, grooves 51 and the like are formed in the inner circumference 50 of the metal cylinder CL. Even if present, the liquid resin composition 42 can be applied with a uniform thickness. In addition, the coating film thickness of the inner circumference of the shaft hole can be controlled by changing the gas flushing pressure.

In this way, after applying the ultraviolet-curable liquid resin composition 42 to the inner circumference of the metal cylinder CL, as shown in FIG. 10 (c), the metal cylinder CL is supported by the support member 46. Then, the ultraviolet rays UV are irradiated to the inner circumferential surface of the metal cylinder CL by the ultraviolet irradiation device 45 while rotating the metal cylinder CL together with the supporting member 46. As a result, the liquid resin composition 42 coated on the inner circumference of the metal cylinder CL is cured to form a coating film 42a having a uniform film thickness.

As the liquid resin composition of the normal temperature curing type, not only the above-mentioned ultraviolet curing resin composition, but also a solvent type resin composition which is dried and cured at normal temperature may be used.

By clamping with a pair of jig 41a, 41b having an opening suitable for the inner circumference of the metal cylinder CL, as shown in Fig. 11, the liquid resin composition 42 on the end face of the metal cylinder CL. You can prevent this extra attachment. Moreover, the film thickness of the inner peripheral part 47 of the upper end surface of the metal cylinder CL is ensured by the upper jig 41a, and the film thickness of the inner peripheral lower part of the metal cylinder CL is ensured by the lower jig 41b. A liquid pooling effect is brought about.

Further, by gas is blown out from the gas supply nozzle 44 to the inner circumference of the metal cylinder CL, as shown in FIG. 12, grooves 51 and the like are formed in the inner circumference 50 of the metal cylinder CL. Even if present, the liquid resin composition 42 can be applied with a uniform thickness. In addition, the coating film thickness of the inner circumference of the shaft hole can be controlled by changing the gas blowing pressure.

In this way, after applying the ultraviolet-curable liquid resin composition 42 to the inner circumference of the metal cylinder CL, as shown in FIG. 10 (c), the metal cylinder CL is supported by the support member 46. Then, the ultraviolet rays UV are irradiated to the inner circumferential surface of the metal cylinder CL by the ultraviolet irradiation device 45 while rotating the metal cylinder CL together with the supporting member 46. As a result, the liquid resin composition 42 coated on the inner circumference of the metal cylinder CL is cured to form a coating film 42a having a uniform film thickness.

As the liquid resin composition of the normal temperature curing type, not only the above-mentioned ultraviolet curing resin composition, but also a solvent type resin composition which is dried and cured at normal temperature may be used.

Claims (9)

In the electrostatic coating method of a metal cylinder having a substantially cylindrical shape formed by laminating metal plates, A support rod is inserted into the shaft hole of the metal cylinder body, and the inner cylinder surface of the metal cylinder body is in contact with the inner circumferential surface to support the metal cylinder body, and the metal cylinder body is disposed above the flow tank of the resin powder. A first coating step of electrostatically attaching the resin powder to the surface of the metal cylinder while rotating the metal cylinder, and heat-sealing the attached resin powder to form a coating film; And a second coating step of applying and curing a liquid resin composition of a room temperature curing type to a portion where the support rod in the shaft hole of the metal cylinder is in contact with the unpainted portion. The annular baffle plate according to claim 1, wherein in the first coating step, the cylindrical cylinder is supported above the flow tank of the resin powder, and the annular baffle plate is arranged at a predetermined distance from the end face of the metallic cylinder. And attaching a resin powder while rotating the metal cylinder. 3. The axial direction of the metal cylinder according to claim 1 or 2, wherein a cover plate having a cross-shaped opening is provided on the upper surface of the flow tank, and the metal cylinder is supported above the opening. It is arranged in one direction of the cross of the opening, the portion along the axial direction of the metal cylinder of the opening has a width shorter than the outer diameter of the metal cylinder, has a length longer than the interval of the baffle plate, The portion of the opening along the axial direction and the right angle direction of the metal cylinder has a width shorter than the shaft length of the metal cylinder and a length longer than the outer diameter. The said metal cylinder is arrange | positioned above the said flow tank, and a suction means is provided in the upper part and / or the side of the said metal cylinder, The resin powder of Claim 1 or 2 characterized by the said suction means. Electrostatic coating method of a metal cylinder, characterized in that to form a flow of. 3. The method of claim 1 or 2, wherein the scraping member is disposed close to the outer circumference of the metal cylinder, and the thickness of the resin powder attached to the outer circumference of the metal cylinder by the scraping member is adjusted. An electrostatic coating method of a metal cylinder characterized by the above-mentioned. The liquid crystal composition according to claim 1 or 2, wherein, in the second coating step, the gas is blown into the inner circumference of the metal cylinder to uniformly expand the liquid resin composition attached to the inner circumference of the metal cylinder. Next, the liquid resin composition is cured to form a coating film. A metal jig according to claim 1 or 2, wherein in the second coating step, a pair of jiges having an opening suitable for the inner circumference of the metal cylinder is held by clamping both end faces of the metal cylinder. And rotating the metal cylinder together with the jig, applying the liquid resin composition to the inner circumference of the metal cylinder and blowing the gas into the inner circumference of the metal cylinder. Way. The uncoated portion of the inner circumference of the metal cylinder is coated with the ultraviolet curable resin composition according to claim 1 or 2, wherein in the second coating step, the ultraviolet curable resin composition is used as the liquid resin composition. And discharging the gas, and then irradiating ultraviolet rays to the inner circumference of the metal cylinder to cure the ultraviolet curable resin composition. The method of electrostatic coating of a metal cylinder according to claim 1 or 2, wherein the metal cylinder is a stator core or a rotor core used for a rotary electric machine.