JPH0193106A - Molded coil and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the deformation of a coil when synthetic resin is poured into the mold by a method wherein a blank coil is formed by closely fixing a sheet-like reinforcement material carrying thermosetting resin to the inner and the outer circumferential surfaces of the coil formed by a conductor and an interlayer insulating material. CONSTITUTION:A blank coil 1 is formed by closely fixing a sheet-like reinforce ment material 4 carrying thermosetting resin to the inner and the outer circum ferential surfaces of the coil on which the conductor consisting of 4-layer alumi num round wire 2 and an interlayer insulating material 3 are laminated, and the above-mentioned material is integrally formed with the coil. Accordingly, the coil 1 is hardly deformed when a synthetic resin material 5 is molded, and it is unnecessary to thickly form the resin material. As a result, the molded coil can be manufactured in an excellent economical manner.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a molded coil for a molded transformer used for power distribution or voltage conversion, and particularly to a molded coil made using a mold.

Conventional technology The method of making a molded coil using a conventional mold is to first create a winding (coil) by winding a conductor (electric wire) around the winding core, and then connect the windings on the required side. It was a bare coil. Then, this raw coil is set in a mold consisting of a core material for casting and an outer frame consisting of a bottom punch and side plates, and after preheating this mold and the raw coil, resin is poured into the mold. A resin hardening material layer was formed around the coil. At this time, the resin filled in the gap between the inner surface of the element coil and the casting core material forms an inner peripheral insulation layer, and the resin filled between the outer side of the element coil and the side plate forms an outer peripheral insulation layer.

Problems to be Solved by the Invention It is sufficient if the thickness of the inner or outer insulating layer is 3 mm, but in the conventional technology, the dimensional accuracy of the coil is poor, so the thickness is 5 to 1 mm.
Approximately 0 mm was required. In other words, even if a coil is formed using a core, when the core is removed, the coil will deform and dent inward or bulge outward, so if resin is cast as is, the insulation layer thickness will be reduced. There was a problem that there was a shortage of places.

As a way to solve this problem, methods are being used to take into account the deformation of the coil in advance and make the casting core material smaller, or to increase the dimensions of the outer frame to ensure at least a certain level of resin thickness. However, this leads to an increase in the amount of resin used and a decrease in heat dissipation.

As a result, I had no choice but to use an expensive transformer.

Another method is to form a heat-fusible resin layer on the outer surface of the wire, heat the core together with the core after one winding, and fuse it.
Methods for preventing coil deformation are known. Although this method is certainly an effective method, it is necessary to form a heat-fusible resin layer on all the wires, which results in an increase in the cost of the wires.

The present invention solves the above-mentioned problems, and aims to provide a molded coil that can ensure the thickness of the insulating layer formed around the bare coil and does not involve a significant increase in cost. It is something to do.

Means for Solving the Problems In order to solve the above problems, the present invention comprises a coil in which a conductor and an insulating material between the eyebrows are wound in layers, and a thermosetting resin is supported on the inner peripheral surface of the coil. a sheet-shaped reinforcing material that is integrated with the coil by closely contacting at least a portion of the outer peripheral surface and the end surface in the axial direction of the core; and a synthetic resin layer formed around the coil and the reinforcing material. It is a gift.

action With the above configuration, before injecting the synthetic resin layer.

Since the coil is integrated with the reinforcing material by the thermosetting resin supported on the reinforcing material, the coil does not deform when casting the synthetic resin layer. Therefore, there is no need to set the resin thickness to be thicker, and costs can be reduced.

Example An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a partial sectional view of a molded coil showing an embodiment of the present invention, and FIGS. 2 and 3 are an external perspective view and a partial sectional view of an elementary coil of the same molded coil. In FIGS. 2 and 3, reference numeral 1 denotes an elementary coil in the shape of a rectangular cylinder with openings on the upper and lower surfaces. The coil is wound to form a coil, and a reinforcing material 4 carrying a thermosetting resin is disposed integrally with the coil on the inner and outer circumferential surfaces of the coil. Then, as shown in FIG. 1, the raw coil 1 is surrounded by a synthetic resin 5 to form a molded coil.

Example 1 Next, specific examples shown in FIGS. 1 to 3 will be explained. The cross-sectional area is 15
As a reinforcing material 4, a rectangular core with a length of 36011 cm and a radius of curvature of 16 mm at the four corners with a size of 0 x 100
After winding an epoxy prepreg with a glass fiber substrate of thickness 0.25 mm and width 110 mm four times, a diameter of 1 mm with an insulating coating is formed. The Om layer round aluminum wire 2 was wound 100 times from a position 5 mm away from the end of the epoxy prepreg wound around the core to form a first layer winding. After that, as an interlayer insulating material 3.

Two polyethylene terephthalate $I (pH!T) films with a thickness of 50μ and a width of 110 are wound three times on the winding, and aluminum round wire 2 is started from the final position of the winding on the film. The second layer winding was formed by winding the wire 100 times while shifting the position in the direction. Thereafter, the film and round aluminum wire 2 were wound in the same manner to obtain a four-layer coil. Next, the epoxy prepreg having a width of 110 mm was wrapped around the outer periphery of the coil as a reinforcing material 4 on the end face. The epoxy prepreg was wound twice together with the epoxy prepreg that was first wound around the core, and then transferred to a dryer and heated at 150° C. for 1 hour to cure the epoxy prepreg. After curing,
After cooling to room temperature, the core was removed to obtain a bare coil 1 in which the epoxy prepreg was tightly integrated. The obtained raw coil 1 was molded into a casting core material with a cross-sectional area of 138 x 86 mm and a radius of curvature of 10 mm at the four corners, and an inner dimension of 162 x 112 mm.
It was transferred to a mold consisting of an outer frame for casting with a radius of curvature of 271 mm at the four corners and a terminal drawer in one direction, and heated to 100°C.
After preheating for 4 hours, an epoxy resin containing 60% filler was vacuum cast as the synthetic resin 5, and heated at 80°C for 10 hours and then at 140°C for 4 hours to harden the epoxy resin. A molded coil having an average 4+sm of epoxy resin layer on the circumference and outer periphery was made.

According to this molded coil, the elementary coil 1 before being surrounded by the epoxy resin is integrated with the cured epoxy prepreg, and an epoxy resin layer having a designed thickness can be obtained when the epoxy resin is cast.

FIG. 4 and FIG. 5 are a perspective view and a partial sectional view of an elementary coil showing another embodiment. In FIGS. 4 and 5, an elementary coil 11 is formed by overlapping and winding a copper foil 12 as a conductor and an interlayer insulating material 13 to form a coil, and carrying a thermosetting resin on the inner peripheral surface of this coil. A reinforcing material 14 is disposed, and another tape-shaped reinforcing material 15 is further wound around two locations of the coil from above the reinforcing material 14 on the inner circumferential surface to be integrated with the coil.

Example 2 Next, specific examples shown in FIGS. 4 and 5 will be explained.

A tape-like reinforcing material 15 of 10 eu+ in width and 10 mm in length (1 layer of hazy tape-like epoxy prepreg was applied to two locations on the straight part of the core used in Example 1 in the axial direction of the core, and then reinforced. As the material 14, an epoxy prepreg with a width of 76mm and 11mm was wound around the core four times.A copper foil 12 with a width of 66mm and a thickness of 20μ and a thickness of 16μ as the glabella insulating material 13 were placed on this epoxy prepreg. A coil was formed by overlapping two sheets of PET film with a width of 74 m and winding it 150 times. After winding, the tape-shaped epoxy prepreg attached to the straight part of the core was wound around the coil, and a polyester tape (Fig. (not shown). This coil was transferred to a dryer together with the core, and heated under the same conditions as in Example 1 to cure the epoxy prepreg. After cooling to room temperature, the core was removed and the epoxy prepreg was An elementary coil 11 that was tightly integrated was obtained.This elementary coil 11 was used in Example 1.
Resin casting was performed in the same manner as above to produce a molded coil having an average 4-layer epoxy resin layer as a synthetic resin on the inner and outer circumferential sides of the bare coil 11.

In the above examples, the reinforcing material supporting the thermosetting resin is not only glass fiber, but also heat-resistant insulating materials such as polymer films such as polyethylene terephthalate and polypropylene, Nomex, and aromatic polyamide laminated paper such as glass paper. Any material may be used as long as it has a thermosetting resin supported on a material with excellent properties. Further, the position of close contact and the number of turns may be determined depending on the type, size, shape, etc. of the electric wire used.

Comparative Example 1 After winding glass cloth with a width of 110 mm, which has the same specifications as the epoxy prepreg substrate used in Example 1, four times around the core used in Example 1, the aluminum circle used in Example 1 was wrapped. A first layer winding was formed by winding the wire 100 times while shifting the wire from a position 5 mm away from the end of the glass cloth.

Thereafter, two sheets of PET film with a thickness of 50 μm and a width of 110 mm were wound three times on the winding wire as an interlayer insulation material, and the aluminum round wire was shifted from the final position of the winding wire in the direction of the winding start on the film. The second layer winding was formed by winding the wire 100 times. Thereafter, the film and round aluminum wire were wound in the same manner to obtain a four-layer coil.

Next, the glass cloth was wound twice around the outer periphery of this coil, and then fixed with Nomex tape. Then, the core was removed to obtain a bare coil.

Comparative Example 2 A glass cloth having a width of 76 mm+, which had the same specifications as the epoxy prepreg base material used in Example 2, was wound four times around the core used in Example 1. The copper foil and PET film used in Example 2 were wound on this glass cloth by the same method as in Example 2 the same number of times. Furthermore, glass cloth, copper foil, and PET film were adhered using adhesive tape to obtain a bare coil of copper foil winding.

The samples obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were comparatively evaluated for dimensional stability. In other words, measure the X and y values shown in Figure 2 as the inner dimensions of the bare coil with the core attached, and after removing the core, measure the x and y values again to determine the deformation of the coil. We investigated the extent of The measurement results are shown in Table 1. Next, Example 1. The raw coils obtained in Example 2, Comparative Example 1, and Comparative Example 2 were set in a mold with dimensions such that the thickness of the inner circumferential insulating layer and the outer circumferential insulating layer was 41 mm, and resin casting was performed. Table 1 also shows the results of measuring the thickness of the resin layer by cutting the straight portion of the molded coil obtained, that is, the section AA shown in FIG. 2.

(Margin below) As can be seen from Table 1, the element coils of Examples 1 and 2 do not change in dimension even after the core is removed, while Comparative Examples 1 and 2 show large dimensional changes. In addition, regarding the thickness of the insulating layer after molding with epoxy resin, the resin thickness according to the Habo design was obtained in the cases using the bare coils of Examples 1 and 2, but on the other hand, in Comparative Examples 1 and 2. Almost no insulating layer was formed.

As described above, according to the present invention, a sheet-like reinforcing material is disposed in close contact with at least a portion of the inner circumferential surface, outer circumferential surface, and end surface in the core axis direction of the coil, and this reinforcing material is heated. The structure is such that the bare coil can be integrated before one synthetic resin layer is cast by carrying a curable resin, and the dimensional stability of the bare coil is good, and the thickness of the synthetic resin layer can be designed. Molded coils that can be obtained on the street can be easily made, and the cost of molded transformers can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a molded coil showing an embodiment of the present invention, FIGS. 2 and 3 are external perspective views and partial sectional views of an elementary coil of the same molded coil, and FIGS. 4 and 5.
The figures are an external perspective view and a partial sectional view of an elementary coil of a molded coil showing another embodiment of the present invention. 1.11...Elementary coil, 2...Aluminum round wire, 3,1
3... Interlayer insulation material, 4.14.15... Reinforcement material (epoxy prepreg), 5... Synthetic resin, 12... Copper foil. Agent Yoshihiro Morimoto Figure 2 Figure 3 Figure 4 Figure 5

Claims (2)

[Claims] 1. The coil is formed by carrying a thermosetting resin and a coil formed by overlappingly wound a conductor and an interlayer insulating material, and is in close contact with at least a portion of the inner circumferential surface, outer circumferential surface, and end surface of the core in the axial direction of the coil. A molded coil comprising a sheet-like reinforcing material that is integrated with a coil, and a synthetic resin layer formed around the coil and the reinforcing material. 2. A sheet-shaped reinforcing material carrying a thermosetting resin is brought into close contact with at least a portion of the inner circumferential surface, outer circumferential surface, and end surface in the axial direction of the coil, and the sheet-shaped reinforcing material and the coil are bonded together by heating and curing. A method for manufacturing a molded coil, which comprises molding a synthetic resin layer around the coil after the coil is integrated.