Resin molded coil and molded transformer using the same

Abstract

 A resin molded coil is configured by providing multiple layers of a prepreg layer (41,42,43,44) and a fiber glass-base layer (31,32,33,34) in the inner/outer circumference resin layers in the radial direction of the concentric circle of a coil (1) and a winding wire to make the resin layer multiply-layered and subdivided. This configuration reduces the resin contraction amount of each layer and increases crack resistance.

Description

[0001] The present invention relates to a technology for providing a molded transformer for power receiving and distribution.

[0002] The related art in this technical field is described in JP-A-2000-12343 (Patent Document 1) and JP-A-11-214237 (Patent Document 2).

[0003] Patent Document 1 and Patent Document 2 given above describe the provision of a manufacturing method of a resin molded coil wherein the resin molded layer is formed in a method easier than that of the prior art and the insulation characteristics are good.

[0004] A resin molded coil, which is formed by molding winding wire, obtained by winding an electrical-insulator-coated conductor, with thermoset resin such as epoxy resin is superior in insulation characteristics and flame resistance and, therefore, is applied primarily to a high-voltage power receiving and distribution molded transformer.

[0005] In the conventional manufacturing method of a resin molded coil, the radially inner/outer circumference of the concentric of the coil is configured by only the resin layer or by one fiber glass base-material layer impregnated with resin and one resin layer to ensure the insulation characteristics as described above.

[0006] For a resin molded coil, it is desired not only to improve the insulation characteristics but to further improve the crack resistance.

[0007] In the conventional configuration of a resin molded coil, the resin contraction amount increases in the resin layer at resin curing time or transformer operation time and, when the resin contraction amount exceeds the allowable stress, it is anticipated that a crack will appear.

[0008] When a crack appears, moisture or dust may enter the coil or the winding wires through the crack, sometimes causing a breakdown in use. This is another problem to be addressed.

[0009] It is a preferred aim of the present invention to provide a resin molded coil, which solves the problems described above, and a molded transformer that uses the resin molded coil.

[0010] The present invention provides many embodiments that may address the problems described above. An example is given below.

[0011] A resin molded coil is configured by providing multiple layers of a prepreg layer and a fiber glass-base layer in the inner/outer circumference resin layers in the radial direction of the concentric circle of a coil and a winding wire to make the resin layer multiply-layered and subdivided. This configuration reduces the resin contraction amount of each layer and increases crack resistance.

[0012] The following describes the configuration of the present invention in another way.

[0013] A resin molded coil comprises an inner circumference side resin layer and an outer circumference side resin layer in the radial direction of a winding wire wherein the inner circumference side resin layer or the outer circumference side resin layer has a plurality of layers of glass base-material.

[0014] The resin molded coil is configured in such a way that a prepreg layer is provided on the inner circumference side of the inner circumference side resin layer and a glass base-material layer is provided on the outer circumference side of the prepreg layer.

[0015] The resin molded coil is configured in such a way that, from the inner circumference side to the outer circumference side in the radial direction of the winding wire, a first prepreg layer, a first glass base-material layer, a second prepreg layer, a second glass base-material layer, the winding wire, a third glass base-material layer, a third prepreg layer, a fourth glass base-material layer, and a fourth prepreg layer are provided.

[0016] The resin molded coil further comprises a resin layer on the top and the bottom of the glass base-material layers in the axial direction of the winding wire.

[0017] The resin molded coil is configured in such a way that the glass base-material is made of fiber.

[0018] The resin molded coil is configured in such a way that the resin layer on the top and the bottom has a fiber glass base-material.

[0019] A molded transformer for power receiving and distribution comprises the resin molded coil; an iron core where the resin molded coil is provided; a connecting terminal to which the resin molded coil is connected; and a metal fitting for securing the resin molded coil.

[0020] The present invention increases the crack resistance of the resin layer and the workability of wire winding as compared to the conventional method and provides a molded transformer superior in dielectric strength and productivity.

[0021] In the drawings

FIG. 1 is a diagram showing an example of the cross section of a resin molded coil in a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of the cross section of a resin molded coil in a second embodiment of the present invention.

FIG. 3 is a diagram showing an example of the top view of the cross section of the resin molded coil in the embodiments of the present invention.

FIG. 4 is a diagram showing the outline of a resin molded transformer in which the resin molded coils of the embodiments of the present invention are provided.

[0022] Embodiments will be described with reference to the drawings.

[First embodiment]

[0023] In this embodiment, the following describes the configuration of the resin layer on the radially inner circumference side and outer circumference side of the molded coil winding wire of a resin molded coil.

[0024] FIG. 1 is a diagram showing an example of the cross section when a resin molded coil in this embodiment is viewed from the side.

[0025] The resin molded coil in this embodiment has a winding wire 1 that acts as a coil, a molded resin layer 2, a glass base-material layer, and a prepreg layer.

[0026] The resin molded coil is configured by the following components from the inner circumference side to the outer circumference side of the coil: first prepreg layer 41, first glass base-material layer 31, second prepreg layer 42, second glass base-material layer 32, winding wire 1, third glass base-material layer 33, third prepreg layer 43, fourth glass base-material layer 34, and fourth prepreg layer 44.

[0027] The molded resin layer 2 is formed by filling and curing resin on and under the first prepreg layer 41, first glass base-material layer 31, second prepreg layer 42, second glass base-material layer 32, winding wire 1, third glass base-material layer 33, third prepreg layer 43, fourth glass base-material layer 34, and fourth prepreg layer 44.

[0028] The structure of the conventional resin molded coil requires that the prepreg tape be wound multiple times to attain the thickness of the prepreg layer on the inner circumference side to increase crack resistance. This winding work requires a long time and therefore decreases the productivity.

[0029] In contrast, in the resin molded coil of the first embodiment shown in FIG. 1, the resin layer is configured by winding the prepreg tape in one turn to form a prepreg layer on the inner circumference side to provide the first prepreg layer 41.

[0030] The first glass base-material layer 31 is provided on the first prepreg layer 41.

[0031] The first glass base-material layer 31 is provided in this way to increase crack resistance.

[0032] Because the first prepreg layer 41 on the inner circumference side is created by winding the prepreg tape in one turn as described above, the winding work time becomes shorter than that in the conventional winding work in which the prepreg tape is wound multiple turns, thus improving productivity as compared to the conventional method.

[0033] As exemplified in FIG. 1, it is also possible to improve crack resistance by providing multiple layers, such as the second prepreg layer 42, in which the prepreg tape is wound once, and the second glass base-material layer 32. In this case too, the reduction in the number of times of prepreg tape winding as compared to the conventional method provides a resin molded coil with better winding workability.

[0034] The molded resin layer 2 is formed by filling and curing resin on and under the prepreg layer, which includes the winding wire 1, first prepreg layer 41, second prepreg layer 42, third prepreg layer 43, and fourth prepreg layer 44, and the glass base-material layer which includes the first glass base-material layer 31, second glass base-material layer 32, third glass base-material layer 33, and fourth glass base-material layer 34.

[0035] In the description above, the number of turns of the prepreg tape is not limited to one but may be wound any number of turns as long as the winding work time can be reduced as compared to the conventional method. This means that the prepreg tape may be wound twice or three times.

[Second embodiment]

[0036] In this embodiment, the following describes the configuration of the top and bottom of the resin layers of a resin molded coil.

[0037] FIG. 2 is a diagram showing an example of the cross section of a resin molded coil in a second embodiment.

[0038] The description is omitted for the parts in the cross section of the resin molded coil in FIG. 2 that have the configuration with the same reference numerals, and have the same functions, as those in FIG. 1 described above.

[0039] In the second embodiment, the molded resin layer 2 is altered.

[0040] As exemplified in FIG. 2, a fiber glass base-material 5 is provided in the molded resin layer 2 at the end of the insulators such as the glass base-material layer and the prepreg layer to cover the end of the insulators such as the glass base-material layer and the prepreg layer.

[0041] This configuration prevents a crack from starting to open at the end of those insulators. The molded resin layer 2 is formed by filling and curing resin on and under the glass base-material layer and the prepreg layer.

[0042] Instead of the glass base-material layer and the prepreg layer, insulators such as an inter-layer insulating film or a glass cloth, for example, TEONEX(R) and LUMIRROR X10S(R), may also be provided.

[Third embodiment]

[0043] FIG. 3 is a sectional view showing an example of forming the resin layer of the resin molded coil 100, exemplified in FIG. 1 and FIG. 2, using resin.

[0044] As shown in FIG. 3, the first prepreg layer 41, first glass base-material layer 31, second prepreg layer 42, and second glass base-material layer 32 on the inner circumference side of the resin molded coil 100 is formed as a resin layer 40A using resin, and the third glass base-material layer 33, third prepreg layer 43, fourth glass base-material layer 34, and fourth prepreg layer 44 on the outer circumference side is formed as a resin layer 40B using resin.

[0045] According to the description above, the resin molded coil 100 has the resin layers, each of which is a layer of resin, in such a way that the resin layer 40A is positioned on the inner circumference side of the winding wire 1 and the resin layer 40B is positioned on the outer circumference side as exemplified in FIG. 3. The sectional shape of the resin molded coil 100 is not limited to circle, but may be quadrilateral.

[Fourth embodiment]

[0046] Next, FIG. 4 shows the outline perspective view of a power receiving/distribution molded transformer in which the resin molded coils 100 are provided.

[0047] The power receiving/distribution molded transformer shown in FIG. 4 comprises an iron core 10, a primary coil provided around the iron core 10 to generate an alternating field, a secondary coil provided between the iron core 10 and the primary coil, a primary terminal 13 provided outside the transformer as the connecting terminal of the primary coil, a secondary terminal 14 provided outside the transformer as the connecting terminal of the secondary coil, and metal fittings 11 and 12 of the transformer.

[0048] An air space, which functions as an insulator and a cooler, is provided between the primary coil and the secondary coil. The metal fittings 11 and 12 comprise the top metal fitting and the bottom metal fitting that secure the iron core 10 and the coil from above and below.

[0049] The primary coil may be configured by divided coils, and resin is cast and cured to configure a resin molded coil. The wire winding method of the divided coils described above is not used for the secondary coil, and a molded coil, formed by winding coil on the metal mold, casting and curing resin, and then removing the metal mold, may be installed.

[0050] The bobbin is made of resin, and a glass roving cloth base-material is used.

Claims

1. A resin molded coil comprising an inner circumference side resin layer (40A) and an outer circumference side resin layer (40B) in the radial direction of winding of a winding wire (1), wherein
said inner circumference side resin layer (40A) or said outer circumference side resin layer (40B) has a plurality of layers of glass base-material (31,32,33,34).

2. The resin molded coil according to claim 1, wherein
a prepreg layer is provided on the inner circumference side of said inner circumference side resin layer and
a glass base-material layer is provided on the outer circumference side of said prepreg layer.

3. The resin molded coil according to claim 1, wherein
from the inner circumference side to the outer circumference side in the radial direction of said winding wire (1), a first prepreg layer (41), a first glass base-material layer (31), a second prepreg layer (42), a second glass base-material layer (32), the winding wire (1), a third glass base-material layer (33), a third prepreg layer (43), a fourth glass base-material layer (34), and a fourth prepreg layer (44) are provided.

4. The resin molded coil according to any one of claims 1-3, further comprising:

a resin layer (2) on the top and the bottom of said glass base-material layers (31,32,33,34) in the axial direction of the winding of the winding wire (1).

5. The resin molded coil according to any one of claims 1-4, wherein
the glass base-material (31,32,33,34) is made of fiber.

6. The resin molded coil according to claim 5, wherein
said resin layer (5) on the top and the bottom has a fiber glass base-material.

7. A molded transformer for power receiving and distribution comprising:

the resin molded coil according to claims 1-3;

an iron core (10) where the resin molded coil is provided;

a connecting terminal (13,14) to which said resin molded coil is connected; and

a metal fitting (11,12) for securing the resin molded coil.

Drawing