JP6853434B2 - Manufacturing method of coil with insulating coating - Google Patents

Description

The present invention relates to a method for manufacturing a coil with an insulating coating by attaching an insulating coating to a flat coil formed by processing a flat lead wire having a flat cross section by electrodeposition coating technology and baking the coil.

Insulating coated electric wires such as so-called enamel wires are manufactured by applying an insulating paint (varnish) based on an insulating resin to the electric wires and baking them, and electrodeposition coating technology is attracting attention as a technique for applying the insulating paint. There is. Further, when the insulating coated electric wire is a coil used for a motor, a transformer, etc., cracks or the like may occur in the insulating coating when the coil is processed into a component shape after the insulating coating is applied in the state of the electric wire. Attempts have been made to insulate an uninsulated bare wire after processing it into the form of a coil.

For example, Patent Document 1 discloses that a workpiece obtained by processing a flat lead wire into an electromagnetic coil shape for a motor (edgewise winding) is electrodeposited and coated. In Patent Document 1, both ends of the work are gripped by chucks and held in a suspended state, and the portion below the gripped portion is immersed in an electrodeposition solution and painted while being conveyed in the suspended state. Then, it is described that an insulating coating is formed by drying or curing after painting.

Further, also in Patent Document 2, both ends of the coil are gripped by a hanger and held in a suspended state, and the portion below the gripped portion is immersed in an electrodeposition solution for coating. It is described that the coating is cured by being placed inside, heated using infrared rays or hot air, and then cooled. Further, it is described that when the film thickness of the insulating film is increased, bubbles are likely to be generated on the surface.

On the other hand, Patent Document 3 discloses a technique for removing bubbles generated in a coating film, and removes air bubbles adhering to the work by taking out the work from the electrodeposition liquid a plurality of times in the middle of the electrodeposition coating process. However, it is described that electrodeposition coating is applied. According to Patent Document 3, if the continuous immersion time in which the work is immersed in the electrodeposition solution without being taken out is lengthened with the elapsed time from the start of the electrodeposition coating process, air bubbles can be efficiently removed. It is said that.

Japanese Unexamined Patent Publication No. 2012-117133 Japanese Unexamined Patent Publication No. 2012-224924 Japanese Unexamined Patent Publication No. 2012-180585

By the way, as described in Patent Document 2, bubbles are likely to be generated in a portion where the coating film is thick. For this reason, when a linear electric wire before being processed into a coil is electrodeposited, it is easy to form a film having a uniform thickness, but after the electric wire is processed into a coil shape, electrodeposition coating is performed. In this case, since the shape has a portion that is wound and overlapped, a bent portion, and the like, the thickness of the coating film tends to vary, and the drying and baking thereof tends to be uneven. Therefore, there is a problem that bubbles are likely to remain.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for manufacturing a coil with an insulating coating, which can reduce the film thickness distribution in the insulating coating.

The method for manufacturing a coil with an insulating coating of the present invention is to attach an insulating paint to a coil component formed by spirally winding a flat lead wire having a flat cross section using a wire coating jig and baking it. The electrodeposition coating jig includes a base and at least a pair of clamps fixed to the base, and the base or at least one of the clamps is a method for manufacturing a coil with an insulating coating. An electrodeposition coating step in which an insulating coating is adhered to a portion between both ends of the coil component , which is formed of a material having good electrical and thermal conductivity and should be insulated, except for both ends. It has a baking step of forming an insulating film on the coil component by baking an insulating paint adhering to the coil component after electrodeposition coating, and the coil component to be insulated coated before the electrodeposition coating process . Both ends are gripped by the respective clamps of the electrodeposition coating jig, and the plurality of winding portions formed between the both ends are maintained in an extended state at intervals, and the extension thereof is maintained. In this state, the electrodeposition coating step and the baking step are performed , and in the electrodeposition coating step, a portion between both ends of the coil component exposed from the clamp is immersed in the electrodeposition tank. A current is passed through the electrodeposition coating jig to the coil component for electrodeposition coating, and in the baking step, heat is transferred to the coil component via the electrodeposition coating jig to transfer the heat to the inside of the coil component. It is characterized by heating from.

By applying electrodeposition coating in a stretched state with intervals between the winding parts of the coil parts, that is, in a linear state without overlapping the winding parts, and performing dry baking, it is uniform around the lead wire. An insulating film having a thickness of various thickness can be formed. In general, air bubbles tend to remain in a thick portion, so that the overall film thickness distribution becomes smaller, so that the residual air bubbles can be reduced and a good quality insulating film can be formed.

In the method for manufacturing a coil with an insulating coating of the present invention, the stretched state may be maintained within the elastic deformation range of the coil component to be insulated.

By maintaining the stretched state of the coil component within the elastic deformation range, the distance between the wound parts is naturally narrowed when the stretched state is released, and the wound parts are easily returned to the original shape in which they are overlapped. be able to. Therefore, the work process for returning the shape of the coil with an insulating coating (coil component) to the original state and the members such as tape used in the work process can be omitted, and the manufacturing process can be simplified.

In the method for manufacturing a coil with an insulating coating of the present invention, it is preferable to hold both ends of the coil component to be insulated in a state parallel to each other to maintain the extended state.

By gripping both ends of the coil parts in a state parallel to each other, electrodeposition coating and dry baking can be performed without contacting the wound parts, and sagging can be suppressed to handle a series of processes. It is also possible to prevent interference with other devices.

According to the present invention, since the insulating paint is adhered and dried and baked in a state where the winding portions of the coil parts are spaced apart, an insulating film having a uniform thickness can be formed on the coil parts, whereby air bubbles can be formed. It is possible to form a high-quality insulating film by reducing the residual amount of the coating material.

It is a perspective view which shows the state which held the coil component in the electrodeposition coating jig used in one Embodiment of the manufacturing method of the coil with an insulating coating of this invention. It is a perspective view which shows the state which put together the electrodeposition coating jig shown in FIG. 1 on a heater. It is sectional drawing which shows typically the example of electrodeposition coating in the manufacturing method of this embodiment. It is a perspective view which shows typically the example of the baking apparatus used in the manufacturing method of this embodiment. It is a perspective view which shows the example of the coil component which is applied the insulating film by the manufacturing method of this embodiment. It is a perspective view of the coil component shown in FIG. 5 in the extended state. It is a top view which shows the example of the coil with an insulating coating with an insulating coating, and shows the film thickness observation cross-sectional position of the insulating coating. It is a cross-sectional view of the coil with an insulating film at each film thickness observation cross-sectional position shown in FIG. 7, and shows the film thickness observation position of the insulating film at each film thickness observation cross-sectional position.

Hereinafter, embodiments of the present invention will be described.
The coil 10 with an insulating coating in this embodiment is a coil segment used for a stator of an electric motor or a generator, and has a flat cross section (t: 0.6 mm × W: 12 mm) as shown in FIG. 8, for example. As shown in FIG. 7, the flat lead wire is spirally wound to form a flat coil component 1, and the central portion 3 (hatched portion in FIG. 7) excluding both end portions 2 is formed by the insulating coating 5. It is insulated and coated. Although not shown, in the coil 10 with an insulating coating, both ends 2 of the coil component 1 where the flat conductors are exposed are coupled to the stator core.

The coil 10 with an insulating coating excludes a molding step of processing a flat lead wire into the shape of a flat coil component 1, a cleaning step of cleaning the processed coil component 1, and both ends 2 of the coil component 1 after cleaning. , An electrodeposition coating step of adhering an insulating paint to the central portion 3 between both end portions 2 by an electrodeposition coating technique, and a baking step of heating the coil component 1 to dry and bake the insulating paint adhering to the coil component 1. It is manufactured through.

In the molding step, the flat lead wire is bent and molded in the plane direction thereof, and processed into a coil component 1 having a plurality of winding portions 4 as shown in FIGS. 5 and 6. Note that FIG. 5 shows a natural state of the coil component 1, and FIG. 6 shows an extended state in which both end portions 2 of the coil component 1 are extended within the elastic deformation range in a state parallel to each other. As described above, in the coil component 1, the winding portions 4 are densely arranged in the natural state. Further, in the examples shown in FIGS. 5 and 6, the winding portion 4 formed in the central portion 3 of the coil component 1 is formed in an oval shape (winding outer diameter is 100 mm × 50 mm), and the winding portion 4 is formed in an oval shape (winding outer diameter is 100 mm × 50 mm). Both end portions 2 are provided so as to extend in the longitudinal direction of the portion 4. The coil component to which the present invention is applied is not limited to the shape shown in FIG. 5, and coil components having various shapes can be adopted.

The electrodeposition coating step is performed in a state where the coil component 1 is held by the electrodeposition coating jig 11 shown in FIG.
The electrodeposition coating jig 11 is a jig for electrodeposition coating on the central portion 3 (the portion hatched in FIGS. 5 and 6) between both end portions 2 except for both end portions 2 of the coil component 1. It is composed of a flat plate-shaped base 12 and a plurality of pairs of clamps 13 fixed to one side of the base 12. Each clamp 13 grips the end portion 2 of the coil component 1, and in the illustrated example, the fixed side clamp member 14 fixed to the base 12 and the movable clamp member 14 fixed to the fixed side clamp member 14 by a screw 15. The side clamp member 16 is provided, and a slot portion 17 for holding the end portion 2 of the coil component 1 in the inserted state is formed by fastening the clamp members 14 and 16 to the opposing portions of the clamp members 14 and 16. Has been done. Further, the slot portion 17 is provided with a spring piece 18 that elastically contacts the end portion 2 of the inserted coil component 1.

In this case, the clamps 13 are fixed on the base 12 in a plurality of rows and arranged in pairs between adjacent rows, as shown by the white arrows in FIG. By inserting and gripping the end portions 2 of the coil component 1 into the slot portions 17 of the pair of clamps 13, the coil component 1 is vertically connected to the base 12 so as to be bridged between the pair of clamps 13. In addition, both ends 2 can be extended within the elastic deformation range of the coil component 1 in a state of being parallel to each other, and the winding portions 4 can be arranged at intervals. Further, by gripping both end portions 2 of the coil component 1 with the clamp 13 in this way, an extended state, that is, a state in which a plurality of winding portions 4 formed between both end portions 2 are spaced apart from each other. Can be maintained. Further, since the paired clamps 13 are arranged in a row on the base 12, the coil parts 1 are also arranged in a row at intervals from each other and in the same posture (FIG. FIG. 2). In the illustrated example, a total of four coil components 1 are arranged on the base 12, and the four coil components 1 form a row.

Further, the base 12 is formed with an opening 19 along the thickness direction so as to remove the central portion thereof. At least one of the base 12 of the electrodeposition coating jig 11 and the pair of clamps 13 is made of a material having good electrical and thermal conductivity, for example, a metal such as aluminum or copper. The clamp 13 is not limited to the type in which the movable side clamp member 16 is fixed by the illustrated screw 15, and may be in the type in which the movable side clamp member 16 is urged by using a spring or the like.

In this way, before the electrodeposition coating process, both ends 2 of the coil component 1 processed by the molding process are gripped by each clamp 13 of the electrodeposition coating jig 11, and the coil component 1 is placed on the base 12. Stand vertically and keep it in the extended state. Then, the coil component 1 is subjected to the electrodeposition coating process in this extended state.
Specifically, the base 12 of the electrodeposition coating jig 11 holding the coil component 1 is supported by a hanger (not shown), and the coil component 1 is suspended. That is, the coil component 1 is supported in a state in which the end portion 2 gripped by the clamp 13 faces upward and the central portion 3 arranged between both end portions 2 faces downward. Further, wiring (both not shown) is connected to the base 12 by an alligator clip or the like. The hanger is formed of an insulator.

Then, as shown in FIG. 3, the coil component 1 in the suspended state is immersed in the electrodeposition tank 22 filled with the insulating paint 21. At this time, except for the end portion 2 gripped by the clamp 13, the central portion 3 exposed from the clamp 13 is immersed in the electrodeposition tank 22, and between the base 12 and the electrode 23 in the electrodeposition tank 22. A current is passed from the DC power supply 24 to the electrodeposition coating.
The insulating paint 21 stored in the electrodeposition tank 22 is an insulating paint (crocodile) based on a polyurethane resin, a polyester resin, a polyesterimide resin, a polyamideimide resin, a polyimide resin, or the like. A curing agent or the like is added.

After being immersed in the electrodeposition tank 22 for a predetermined time, the coil component 1 is pulled up from the electrodeposition tank 22 and the paint (insulating paint 21) adhering to the coil component 1 is baked.

Then, in the baking step, the baking apparatus 31 shown in FIG. 4 is used. In this baking device 31, a receiving station 34 is installed at the entrance of a passage 33 surrounded by a tunnel-shaped heat insulating cover 32, and a drying station 35, a baking station 36, and a cooling station 37 are sequentially installed inside the heat insulating cover 32. Then, the take-out station 38 is installed at the exit of the passage 33. A heater 39 is provided at each of the drying station 35 and the baking station 36, and a blower (not shown) for supplying cold air is provided at the cooling station 37. Further, each of these stations 34 to 38 is separated by a shutter. The transfer between the stations 34 to 38 is performed by intermittently moving the coil component 1 by, for example, an intermittent transfer means (not shown) such as a walking beam.

The heater 39 installed in the drying station 35 and the baking station 36 is formed in a plate shape, is installed horizontally on the passage 33, and its upper surface is a heat radiating surface 39a. Then, the baking step is also performed by holding the coil component 1 in the stretched state by the electrodeposition coating jig 11 as in the electrodeposition coating process. As a result, the water and the organic solvent contained in the insulating coating material 21 can be uniformly and sufficiently removed.

First, with the coil component 1 facing upward, the base 12 of the electrodeposition coating jig 11 is sequentially conveyed from the receiving station 34 onto each heater 39. Then, as shown in FIG. 2, when the base 12 holding the coil component 1 is placed on the heat radiating surface 39a of the heater 39, the base 12 and the clamp 13 are made of a material having good heat conduction (aluminum, copper, etc.). ), The heat of the heater 39 is quickly transmitted from the heat radiating surface 39a and conducted inside, and is transmitted from the clamp 13 to the end portion 2 of the coil component 1 and conducted in the coil component 1 in the length direction. To do. At this time, since the coil component 1 is an electrically good electric body and is excellent in heat conduction, it can be heated quickly and the paint adhering to the coil component 1 can be heated from the inside. Further, since the opening 19 is formed in the base 12, the radiant heat from the heater 39 in the portion facing the opening 19 is transmitted to the coil component 1, and the paint adhering to the coil component 1 is also heated from the outside. Can be done. Further, heat dissipation is suppressed by the heat insulating cover 32, and the coil component 1 can be effectively heated.

In this way, at the drying station 35, the coil component 1 is heated to, for example, 150 ° C. by the drying heater 39 to dry the insulating paint, and at the baking station 36, the coil component 1 is heated, for example, 250 by the baking heater 39. Heat to ℃ and bake the paint. Finally, after cooling at the cooling station 37, the coil is taken out from the take-out station 38, and the end portion 2 of the coil component 1 is removed from the clamp 13 of the electrodeposition coating jig 11 to obtain a product as a coil with an insulating coating.

As described above, in the electrodeposition coating of this embodiment, in the series of steps from the electrodeposition coating step to the baking step, the winding portions 4 are extended at intervals within the elastic deformation range of the coil component 1. Electrodeposition coating can be applied in a state, that is, in a linear state without overlapping the winding portions 4, and dry baking can be performed. As a result, the insulating coating 5 having a uniform thickness can be formed around the lead wire of the coil component 1, and the residual air bubbles can be reduced to form the insulating coating 5 of good quality.

Further, since both end portions 2 of the coil component 1 project laterally from the winding portion 4, the central portion of the winding portion 4 due to the weight of the winding portion 4 when the coil component 1 is suspended. May be in a hanging state. In this respect, in the present embodiment, by holding both end portions 2 of the coil component 1 in a state of being spread parallel to each other, electrodeposition coating and dry baking can be performed without contacting the winding portions 4. At the same time, it is possible to suppress the hanging of the winding portion 4 and prevent interference with other equipment or the like during the handling of a series of steps. Therefore, the handling of the coil component 1 can be facilitated.

Further, in the baking step, the heat of the heater 39 is transmitted from the end 2 of the coil component 1 in the length direction to heat the coil component 1 from the inside, so that the paint adhering to the coil component 1 is also directed from the inside to the outside. Even if air bubbles remain in the paint adhering to the coil component 1, the air bubbles are pushed from the inside to the outside by the gradually thickened cured layer, and the air bubbles are easily removed from the surface. Therefore, the residual bubbles can be further reduced, and a high-quality insulating coating 5 can be formed.

In the above embodiment, before the electrodeposition coating process, the coil component 1 to be insulated is stretched within the elastic deformation range to maintain the winding portions 4 at intervals. The coil component 1 may be plastically deformed to maintain a state in which the winding portions 4 are spaced apart from each other.
When the stretched state of the coil component 1 is maintained within the elastic deformation range, when the stretched state is released after the baking process, the distance between the winding portions 4 is naturally narrowed, and the winding portions 4 are overlapped with each other. Can be easily restored to the shape of (the state before the electrodeposition coating process). Therefore, as compared with the case where the coil component 1 is plastically deformed, the work process for returning the shape of the coil 10 with an insulating coating (coil component 1) to the original state and members such as tape used in the work process are omitted. It can simplify the manufacturing process.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, in the baking step, the heat of the heater 39 is transferred from the end 2 of the coil component 1 to heat the coil component 1 from the inside, but the coil component 1 may be heated from the outside. Further, in the embodiment, both end portions 2 of the coil component 1 are held by the electrodeposition coating jig 11, and both end portions 2 thereof are placed on the heater 39. Only one end may be placed on the heater 39 so that heat is conducted from one end to the entire coil component 1. In that case, the clamp that grips one end of the clamp may be made of a heat conductive material.

The following experiments were carried out to confirm the effect of the present invention.
As shown in FIG. 8, the coil component is formed by spirally winding a flat lead wire having a flat cross section (t: 0.6 mm × W: 12 mm) 10 times with oxygen-free copper to form an oval winding portion. A product formed in a shape (flat shape having an outer diameter of 100 mm × 50 mm) was produced. The electrodeposition coating jig having the configuration shown in FIG. 1 was produced, and the base and clamp of the electrodeposition coating jig were manufactured using aluminum. Then, the coil parts are mounted on the electrodeposition coating jig, the spacing between the winding portions is maintained under the conditions shown in "distance between the coil winding portions" in Table 1, and the insulation mainly composed of polyamide-imide (PAI) is maintained. The electrodeposition coating process was performed using a coating material and an insulating coating material mainly composed of a polyimide (PI) resin. Further, after the electrodeposition coating process, an electrodeposition coating jig is placed on the heater in the same manner as described in the embodiment, and the electric wire parts are heated by heat conduction to perform a baking process. A coil with an insulating coating was produced.

In Examples 1 to 8, the coil parts are maintained in an stretched state within the elastic deformation range in the electrodeposition coating step and the baking step, and in Example 9, the coil parts are elastically deformed in the electrodeposition coating step and the baking step. It was maintained in an elongated state by causing plastic deformation beyond the inside. Further, in Comparative Example 1, the coil parts were not stretched in the electrodeposition coating step and the baking step, that is, they were maintained in a natural state without being elastically deformed or plastically deformed.

In the baking step, the temperature was raised to 150 ° C., held at 150 ° C. for 5 minutes to dry, then held at 250 ° C. for 3 minutes for baking, and then cooled. The rate of temperature rise was as shown in Table 1. Then, after the baking step, the film thickness of the insulating coating formed on the coil with the insulating coating was measured, and the residual state of the bubbles was inspected.

The film thickness of the insulating coating was measured using a KEYENCE microscope (VHX-5000). Further, as shown by the alternate long and short dash lines a1 to a8 in FIG. 7, the cross sections of the straight portion and the bent portion of each oval winding portion (10 times in total) were observed, and the cross sections of these eight locations were observed. In each cross section, as shown by the alternate long and short dash lines b1 to b2 in FIG. 8, by measuring the film thickness of the insulating coating at a total of 8 locations of the flat portion and the corner portion, 10 × 8 = 80 locations for each coil with the insulating coating. The film thickness of the insulating coating was measured.
Then, using the following equation (1), the variation in the film thickness of the insulating coating in each coil with the insulating coating was calculated. The average value of the equation (1) is a value obtained by averaging the measured values of the film thicknesses of the insulating coatings at 80 points.
[| {(Measured value of film thickness farthest from the average value)-(Average value)} | / (Average value)] x 100 (%) ... (1)

In addition, the inspection of air bubbles was performed by visual observation. Then, there were bubbles that could be visually confirmed, those having 5 or more bubbles were marked with "x", those with 1 to 4 bubbles were marked with "Δ", and no bubbles could be confirmed by visual observation. The case was set as "○".
These results are shown in Table 1.

As is clear from Table 1, when the interval between the wound portions is 1 mm or more (Examples 1 to 7 and 9), the variation in the film thickness of the insulating coating is 20% or less, and the thickness is uniform. An insulating film could be formed, and no bubbles remained in the insulating film. When the distance between the wound portions was less than 1 mm (Example 8), small bubbles were generated, but the level was not a problem in actual use.
Further, as can be seen from Table 1, the larger the interval between the wound portions, the smaller the variation in the film thickness of the insulating coating can be. As can be seen by comparing the results of Example 7 and Example 9, even if the distance between the wound portions exceeds the elastic deformation range (15 mm or less), the change in the film thickness of the insulating film does not change. There wasn't.
On the other hand, in Comparative Example 1 in which the coil winding portions are in contact with each other without a gap (0 mm), the film thickness of the insulating coating varies widely and 5 or more bubbles are generated. did.

Based on these results, in the electrodeposition coating process and the baking process, the variation in the film thickness of the insulating coating can be reduced and the generation of air bubbles can be suppressed by maintaining the wound portion of the coil component in an elongated state at intervals. I understand. Further, it can be seen that by providing a spacing of 1 mm or more between the wound portions, the variation in the film thickness of the insulating film can be further reduced, and a high-quality insulating film without residual bubbles can be formed.

1 ... Coil part 2 ... End 3 ... Central part 4 ... Winding part 5 ... Insulating coating 10 ... Coil with insulating coating 11 ... Electrodeposition coating jig 12 ... Base 13 ... Clamp 14 ... Fixed side clamp member 15 ... Screw 16 ... Movable side clamp member 17 ... Slot part 18 ... Spring piece 19 ... Opening 21 ... Insulating paint 22 ... Electrode electrode 24 ... Electrode 24 ... DC power supply 31 ... Baking device 32 ... Insulation cover 33 ... Passage 34 ... Accepting station 35 ... Drying station 36 ... Burning station 37 ... Cooling station 38 ... Extraction station 39 ... Heater 39a ... Heat dissipation surface

Claims (3)

This is a method of manufacturing a coil with an insulating coating by applying an insulating paint to a coil component formed by spirally winding a flat lead wire having a flat cross section using an electric wire coating jig and baking it. hand,
The electrodeposition coating jig includes a base and at least a pair of clamps fixed to the base, and the base or at least one of the clamps is made of a material having good electrical conduction and thermal conductivity. ,
An electrodeposition coating process in which an insulating paint is adhered to a portion between both ends of the coil component to be insulated by electrodeposition.
It has a baking step of forming an insulating film on the coil component by baking the insulating paint adhering to the coil component after electrodeposition coating.
Prior to the electrodeposition coating step , both ends of the coil component to be insulated are gripped by the clamps of the electrodeposition coating jig, and a plurality of winding portions formed between the both ends. It is maintained in an stretched state with an interval between them, and the electrodeposition coating step and the baking step are performed in the stretched state, and at the same time,
In the electrodeposition coating step, a portion between both ends of the coil component exposed from the clamp is immersed in an electrodeposition tank, and an electric current is passed through the coil component via the electrodeposition coating jig. Electrodeposition coating,
The baking step is a method for manufacturing a coil with an insulating coating , which comprises transferring heat to the coil component via the electrodeposition coating jig and heating the coil component from the inside. The method for manufacturing a coil with an insulating coating according to claim 1, wherein the stretched state is maintained within the elastic deformation range of the coil component to be insulated. The method for manufacturing a coil with an insulating coating according to claim 1 or 2, wherein both ends of the coil component to be insulated are gripped in a state parallel to each other to maintain the extended state.

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