Iron Core Joint Structure of Stationary Induction Apparatus and Iron Core Joint Method

Abstract

Generation of broken pieces of thin magnetic ribbons is reduced with respect to a joint part of an iron core, which is formed by laminating the thin magnetic ribbons, of a stationary induction apparatus. There is provided an iron core joint structure of the stationary induction apparatus characterized such that in a butt joint part of the iron core, which is configured with the laminated thin magnetic ribbons, of the stationary induction apparatus, a first resin penetrated into the laminated magnetic ribbons is applied to each of butt joint surfaces facing each other, and a second resin is further applied to an outer side of the first resin.

Claims

1. An iron core joint structure of a stationary induction apparatus, wherein in a butt joint part of an iron core, which is configured with laminated thin magnetic ribbons, of the stationary induction apparatus, a first resin penetrated into the laminated magnetic: bodies is applied to each of butt joint surfaces facing each other, and a second resin is further applied to an outer side of the first resin.

2. The iron core joint structure of the stationary induction apparatus according to claim 1, comprising a member that covers an end portion of the second resin.

3. The iron core joint structure of the stationary induction apparatus according to claim 2, wherein the member that covers the end portion of the second resin exhibits an electric insulation performance.

4. The iron core joint structure of the stationary induction apparatus according to claim 1, wherein the first resin has a viscosity equal to or lower than 10 Pa.Math.s during application and a modulus of elasticity equal to or lower than 10 MPa during hardening, and the second resin has a modulus of elasticity equal to or lower than 1.0 GPa.

5. An iron core joint method for a stationary induction apparatus, comprising: in a butt joint part of an iron core, which is configured with laminated thin magnetic ribbons, of the stationary induction apparatus, applying a first resin penetrated into the laminated magnetic bodies to each of butt joint surfaces facing each other; and further applying a second resin to an outer side of the first resin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 shows an embodiment of the present invention.

[0013] FIG. 2 is an explanatory diagram of an iron core of a stationary induction apparatus.

[0014] FIG. 3 shows an iron core formed by being cut at two portions.

[0015] FIG. 4 shows an embodiment of the present invention.

[0016] FIG. 5 shows an iron core formed with a plurality of wound iron cores.

MODES FOR CARRYING OUT THE INVENTION

[0017] Embodiments of the present invention will be described hereinafter.

[0018] A structure called wound iron core is normally used as a structure of an iron core, which uses thin magnetic ribbons, of a transformer. The wound iron core has the structure in which the thin ribbons are laminated in a radial direction and connected so that the thin ribbons are partially overlaid.

[0019] FIG. 2 is an explanatory diagram of the wound iron core. Reference character 1 denotes a wound iron core body, 2 denotes a lamination surface, and 3 denotes a joint part in which thin ribbons are overlaid. For manufacturing a large-sized iron core, in particular, it is conceivable that the iron core is configured by, for example, dividing the iron core into a plurality of regions. FIG. 3 shows a case of forming the iron core by cutting the iron core at two portions. In this case, a transformer is formed by cutting the iron core at the two portions,, dividing the iron core into an upper iron core 5 and a lower iron core 6, and assembling the upper iron core 5 and the lower iron core 6 again after insertion of a winding.

[0020] It is supposed, for example, that Fe-based amorphous materials are used. In this case, a thickness of each Fe-based amorphous material is about 25 m, so that several thousands of Fe-based amorphous materials are laminated to have a thickness of about 100 mm. Lamination surfaces 4 are continuously liable to an electromagnetic attractive force while the transformer is in operation. Owing to this, the upper iron core 5 and the lower iron core 6 repeatedly strike against each other by the magnetic attractive force on the lamination surfaces 4. As a result, the thin magnetic ribbons are broken, and broken pieces thereof float within the transformer, which causes deterioration of an insulation performance. To address the problem, a structure shown in FIG. 1 is used to inhibit generation of the broken pieces.

First Embodiment

[0021] A first embodiment of the present invention will be described with reference to FIG. I. The present structure is intended to suppress the broken pieces of the thin magnetic ribbons from flying by providing an application material on each lamination surface 4 that faces that of a counterpart iron core in the joint part. Specifically, an A-material that has a low viscosity and that is finally hardened is applied to the lamination surface 4, as described in detail below. It is thereby possible to penetrate the A-material into lamination intermediates 11 between laminated thin magnetic ribbons 15 as shown in an enlarged view in FIG. 1, and to apply the A-material to not only each lamination surface 4 but also a region at a certain width as indicated as an A-material penetration region 10 in FIG. 1. It is thus possible to suppress the broken pieces of the thin magnetic ribbons from flying outside even if the thin magnetic ribbons are broken by an external force.

[0022] Furthermore, after applying the A-material, a B-material 12 hardened in a state of a low modulus of elasticity is applied. The B-material 12 is applied in such a manner as to cover each lamination surface 4 which faces that of the counterpart iron core in the joint part and a side surface 13 of the iron core with the B-material 12. The A-material is penetrated into lamination intermediates 11 between the magnetic materials 15 and hardened; thus, applying the B-material to the lamination surface 4 can facilitate application work without penetration of the B-material 12 into the lamination intermediates again. This enables a region beyond the lamination surface 4 to be covered with the B-material 12; thus, it is possible to further inhibit the broken pieces from flying into the transformer.

[0023] FIG. 4 shows a structure for preventing the B-material 12 from peeling off from an end surface 14. It is considered that a contact state of the end surface 14 of the B-material 12 is partially poor due to, for example, a foreign substance or the like, and that the applied B-material 12 peels off from the portion. To address the peeling, the structure is provided such that a cover 16 is wrapped around the end surface 14 of the B-material so that the end surface 14 thereof is covered with the cover 16 on a side surface of the iron core. The cover 16 can be realized by using an insulating material of a tape shape. It is thereby possible to take measures against the peeling of the B-material from the end surface 14 thereof.

[0024] FIG. 5 shows an embodiment for forming an iron core with a plurality of wound iron cores. This is needed when a large-sized iron core is manufactured. In a case of configuring the iron core using the plurality of iron cores, the iron core is configured as follows although each iron core is identical in structure to those according to the first and second embodiments.

[0025] In FIG. 5, the iron core has four wound iron cores 20, 21, 22, and 23. In this case, the four iron cores are configured to provide interlinkage with the winding. That is, as shown in FIG. 5, the iron core is formed by a combination of the four iron cores. In a case of such a configuration, the A-material that has the low viscosity and that is finally hardened is applied to each lamination surface 4, which faces that of the counterpart iron core in the joint part, of each of the iron cores 20, 21, 22, and 23. A cover 26 is then wrapped to integrate the four iron cores.

[0026] After integration, a B-material hardened in the state of the low modulus of elasticity is applied to cover the A-material. The B-material 25 is applied in such a manner as to cover each lamination surface 4 which faces that of the counterpart iron core in the joint part and the side surface of each of the iron cores with the B-material 25. To prevent the B-material 25 from peeling off from the end surface thereof, the structure is provided such that the cover 26 is wrapped around the end surface thereof so that the end surface thereof is covered with the cover 26 on the side surface of each of the iron cores. Such a configuration can inhibit the broken pieces of the thin magnetic ribbons from flying into the transformer even if the iron core is formed with the plurality of wound iron cores.

[0027] For example, a material that has a viscosity equal to or lower than 10 Pa.Math.s during application and a modulus of elasticity equal to or lower than 10 MPa during hardening with hardening time being equal to or longer than 30 minutes is used as the A-material, and a material that has a modulus of elasticity equal to or lower than 1.0 GPa is used as the B-material. Specifically, a silicone resin, an acrylic-modified silicone resin, an epoxy-modified silicone resin, or a mixture resin of a phenol resin and a rubber at a low viscosity is used.

[0028] In the present embodiments configured as described so far, a butt joint part structure characterized as follows is provided. The butt joint part structure is configured with a first resin penetrated into laminations on each butt surface in a butt joint part of an iron core, and a second resin covering the butt surface. A material that has a low viscosity and that is finally hardened is used as the first resin. A material that has a high viscosity during application and that is finally hardened in a state of a low modulus of elasticity is applied as the second resin after application of the first resin. Realizing the butt joint part structure characterized as described above makes it possible to provide a joint part structure that inhibits the broken pieces of the thin magnetic ribbons from flying within the transformer.

DESCRIPTION OF REFERENCE CHARACTERS

[0029] 1: Wound iron core [0030] 2: Lamination surface [0031] 3: Thin magnetic ribbon [0032] 4: Lamination surface [0033] 5: Upper iron core [0034] 6: Lower iron core [0035] 10: A-material penetration region [0036] 11: Lamination intermediate [0037] 12: B-material [0038] 16: Cover [0039] 20: Element of a plurality of iron cores [0040] 21: Element of a plurality of iron cores [0041] 22: Element of a plurality of iron cores [0042] 23: Element of a plurality of iron cores