TW201905943A - Oil-filled transformer and production method for tank used therein - Google Patents

Abstract

The objective of the invention is to provide an oil-filled transformer wherein the heat-dissipating characteristics and the strength of the tank, and a size reduction of the oil-filled transformer, have been taken into consideration. In order to attain this objective, the oil-filled transformer which is filled with an insulating oil houses an iron core-coil assembly assembled from an iron core and a coil inside the tank, wherein the tank has a bottom plate, a flange for mounting a lid, and a trunk section comprising a side plate located between the flange and the bottom plate, the trunk section having a plurality of embossed parts formed on the surface thereof, and the trunk section being constituted by welding the side plate having the embossed parts formed thereon into a cylindrical shape, wherein a weld section is constituted by welding in such a manner as to overlap some of the embossed parts.

Description

Oil-immersed transformer and method for manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an oil-immersed transformer, and more particularly to a tank for an oil-immersed transformer that takes into account miniaturization, heat dissipation, and strength.

Generally, oil-immersed electrical machines, such as tanks for oil-immersed transformers, are filled with insulating oil as an insulating medium for the transformer. The insulating oil expands due to an increase in temperature due to the heat of the transformer, and increases the internal pressure of the groove. Therefore, sufficient strength is required in order to prevent deformation of the groove. Further, heat dissipation performance capable of suppressing an increase in the temperature of the insulating oil having a low heat transfer is required. Japanese Patent Laid-Open No. Sho 53-35122 (Patent Document 1) is known as a prior art. Patent Document 1 is a method in which a sheet is bent into a wave shape to form a fin-shaped projecting portion, and each of the protruding portions has a groove formed in an oil-immersed electric device of a side plate of the protruding oil chamber, and the upper end portion of the protruding portion is inwardly a narrow surface joint portion is formed, and the upper end portion of the protruding portion is welded along the surface joint portion, and only the weld line is uniaxial, and a convex shape is formed on the flat plate of the protruding portion. Alternatively, the concave reinforcing beads may be used to increase the mechanical strength of the protruding portion by the reinforcing beads. [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 53-35122

[Problems to be Solved by the Invention] In the prior art disclosed in Patent Document 1, when the fin-shaped projecting portion of the heat radiating rib is caused by an increase in the temperature of the insulating oil in the groove, the internal pressure is increased. The reinforcing beads are used to increase the strength in the lateral and longitudinal directions of the projections. However, the reinforcing ribs are provided on the heat radiating ribs to increase the strength, and accordingly, the burden on the surface joint portion of the heat radiating ribs is increased, and there is a problem that a higher bonding method is required, resulting in an increase in cost. Further, when the insulating oil is heated by the energization of the coil conductor provided on the core, it rises above it, flows from the inside of the heat radiating rib, and is cooled by the heat radiating action of the heat radiating rib, thereby self-heating The ribs are circulated in such a manner that the outer peripheral side is lowered and returned to the coil side. Therefore, in order to improve the heat dissipation performance, the heat dissipation ribs must be enlarged to expand the heat dissipation area. Therefore, there is a problem that the so-called oil-immersed transformer is enlarged as a whole. The present invention has been made in view of the above problems, and an object thereof is to provide an oil-immersed transformer which takes into consideration the miniaturization of an oil-immersed transformer, the heat dissipation property of a groove, and the strength. [Means for Solving the Problems] In view of the above-described prior art, the present invention is an oil-immersed transformer in which an iron core-coil assembly in which a core and a coil are assembled is housed in a groove and filled with insulating oil. The groove is provided with a flange for mounting the cover, a bottom plate, and a main body portion including a side plate disposed between the flange and the bottom plate, and a plurality of embossed portions are formed on the surface of the main body portion, and the main body portion is borrowed The side plates of the embossed portion are formed by welding in a cylindrical shape, and the welded portions are welded so that the embossed portions are stacked. [Effects of the Invention] According to the present invention, it is possible to provide an oil immersed transformer which takes into consideration the miniaturization of the oil immersed transformer and the heat dissipation and strength of the groove.

Hereinafter, embodiments of the present invention will be described using the drawings. Fig. 1 is a schematic perspective view of the entire groove of the embodiment. In FIG. 1, the groove 10 is configured to include a flange 11 for attaching a cover, a bottom plate 12, and a main body portion 13 including a side plate disposed between the flange 11 and the bottom plate 12, and the core is assembled by the storage. The core-coil assembly with the coil and the insulating oil used to insulate it. The main body portion 13 is formed by pressing a thin sheet of a sheet shape, for example, a steel sheet. 2 is a transverse cross-sectional view of the oil immersed transformer of the present embodiment as seen from above. Fig. 2 shows an oil immersed transformer including a 3-phase 3-pin structure of U phase, V phase, and W phase. In FIG. 2, inside the groove 10 having a rectangular parallelepiped shape, the core-coil assembly 20 is housed in each phase, and the insulating oil 30 is filled around the core-coil assembly 20. The core-coil assembly 20 is provided with coils 22 of the respective phases at the leg portions of the core 21. The coil 22 is composed of a primary coil portion 23 and a secondary coil portion 24. Fig. 3 is a perspective view showing the entire groove in which the heat radiating ribs are provided as a premise of the present embodiment. As shown in FIG. 3, in order to increase the heat dissipation area, it is conceivable to provide the heat dissipation ribs 40 at specific intervals on the outer side of the main body portion 13 of the groove 10 in accordance with the previous groove structure. However, as described above, if the heat dissipation ribs are provided and the heat dissipation ribs are enlarged in order to further improve the heat dissipation effect, there is a problem that the entire oil-immersed transformer is enlarged. Therefore, in the present embodiment, in order to increase the heat dissipation area around the groove, a plurality of convex portions, that is, embossed portions 50 are formed in the main body portion 13 of the groove. Fig. 4 is a perspective view showing the entire groove of the embodiment. As shown in FIG. 4, in the present embodiment, in order to increase the heat dissipation area around the groove, a plurality of embossed portions 50 are formed in the main body portion 13 of the groove. Each of the embossed portions 50 is arranged side by side or in a lattice arrangement at a predetermined interval around the main body portion 13. Further, each of the embossed portions 50 is formed to protrude in a hemispherical shape, for example, and is continuously disposed, and a heat dissipating surface having high heat transfer is formed. In addition, in FIG. 4, the embossed part 50 may be a convex part, and may be set as a recessed part. In this manner, since the embossed portion of the convex portion or the concave portion is formed in the main portion of the groove, the size of the entire oil immersed transformer can be suppressed and the heat dissipation area can be increased, and the heat dissipation property can be further improved. Further, the strength of the groove can be increased by forming the embossed portion of the convex portion or the concave portion. In addition, the main body portion 13 is formed by press-processing a sheet-like thin plate. However, in order to form the tubular main body portion from the sheet-like side plate, it is necessary to connect the end portions of the side plates by welding or the like. Fig. 5 is a schematic perspective view showing a longitudinal section of the entire oblique viewing groove. In addition, in Fig. 5, the embossed portion is omitted. In order to form the main body portion 13, for example, each of the longitudinal half sides of the main body portion 13 shown in Fig. 5 is embossed by press working and bent, and the longitudinal half side after molding is observed from the upper surface. Two U-shaped side plates are manufactured by fusion bonding. Alternatively, one sheet may be formed and welded into a cylindrical shape. The line A-A in Fig. 5 indicates the portion to be welded, that is, the weld line. Fig. 6 is an enlarged schematic view showing a welded portion of the side plates constituting the main body portion 13. The A-A line indicates the weld line of Fig. 5. In Fig. 6, the welded portion is welded to each other by the flat plate portion 60 to which the embossed portion is not applied. On the other hand, in Fig. 7, the portion where the flat plate portion 60 and the end portion of the embossed portion 50 are overlapped is welded. The welding system performs a welding operation along the weld line, so that the molten metal which is melted and solidified during the welding has a certain width to form a welded portion. Therefore, according to the welding of Fig. 7, since the embossed portion is welded, the welding distance is longer than the linear distance in the longitudinal direction of the side plate. Therefore, there is a so-called strength improvement effect as compared with the case where the flat plate portions 60 of Fig. 6 are welded to each other. Moreover, FIG. 8 is welded to a portion where the flat plate portion 60 and one of the embossed portions 50 are half-folded. According to this, since the welding is performed with a portion having a curvature higher than that of the embossed portion, the welding distance is further extended as compared with the case of FIG. Therefore, there is a so-called strength and thus a feature of improvement. Moreover, the three-dimensional welding can be realized, and the strength is further improved. Moreover, FIG. 9 is an example in which the end portions of the embossed portion 50 are welded to each other. In this example, in the case where the flat plate portions 60 are welded to each other, the welding distance is also prolonged, so that the so-called strength is improved. Further, Fig. 10 is a portion in which the end portion of the embossed portion 50 is half-joined with one of the embossed portions 50. In this case, the welding distance is extended as compared with the case where the flat plate portions 60 are welded to each other, and the three-dimensional welding can be further achieved and the strength can be further improved. Further, Fig. 11 is a portion in which one of the embossed portions 50 is half-stacked and welded to each other. In this case, the welding distance is extended as compared with the case where the flat plate portions 60 are welded to each other, and the three-dimensional welding can be further achieved and the strength can be further improved. As shown in FIG. 7 to FIG. 11 above, by welding the welded portions so that the embossed portions are stacked, the welding distance is extended, and the three-dimensional welding can be further achieved and the strength can be further improved. In addition, in the welding of the side plates, the side plates may be butted and welded, and the side plates may be overlapped to weld the end portions of the side plates. Further, the embossed portion can be used as a positioning reference at the time of welding. Further, since the embossed portions are periodically arranged, if the embossed portions of the joined side plates are overlapped and welded, the embossed portions themselves can be used as the positioning of the welding. In addition, a dedicated embossed portion can be provided for positioning. As described above, in the present embodiment, the embossed portion of the convex portion or the concave portion is formed in the side plate forming the groove main body portion, and is bent and formed, and when the side plate is welded in a cylindrical shape, the welded portion is stacked on the embossed portion. Welding. Thereby, the heat dissipation rib can be provided in the groove to reduce the size, and the heat dissipation property of the embossed portion can be improved and the strength of the groove can be improved, and the strength of the groove can be further improved.

10‧‧‧ slots

11‧‧‧Flange

12‧‧‧floor

13‧‧‧ Main body

20‧‧‧core-coil assembly

21‧‧‧ iron core

22‧‧‧ coil

23‧‧‧One coil department

24‧‧‧second coil

30‧‧‧Insulating oil

40‧‧‧Solid ribs

50‧‧‧ embossed department

60‧‧‧ flat section

A-A‧‧‧ line

Fig. 1 is a schematic perspective view of the entire groove of the embodiment. Figure 2 is a cross-sectional view of the oil immersed transformer of the embodiment. Fig. 3 is a perspective view showing the entire groove of the heat dissipating rib provided on the premise of the embodiment. Figure 4 is a perspective view of the entire groove of the embodiment. Fig. 5 is a schematic perspective view showing a longitudinal section of the entire groove of the embodiment in an oblique manner. Fig. 6 is an enlarged schematic view showing a welded portion of a groove side plate which is a premise of the embodiment. Fig. 7 is an enlarged schematic view showing a first example of a welded portion of the groove side plate of the embodiment. Fig. 8 is an enlarged schematic view showing a second example of the welded portion of the groove side plate of the embodiment. Fig. 9 is an enlarged schematic view showing a third example of the welded portion of the groove side plate of the embodiment. Fig. 10 is an enlarged schematic view showing a fourth example of the welded portion of the groove side plate of the embodiment. Fig. 11 is an enlarged schematic view showing a fifth example of the welded portion of the groove side plate of the embodiment.

Claims (11)

An oil-immersed transformer comprising: a core-coil assembly in which an assembled core and a coil are housed in a groove, and filled with insulating oil; and the groove has a flange for mounting a cover, and a bottom plate a main body portion including a side plate disposed between the flange and the bottom plate; a plurality of embossed portions formed on a surface of the main body portion; and a side plate of the embossed portion formed by welding the main body portion in a tubular shape Further, the welded portion is welded in such a manner that the embossed portions are stacked. The oil-immersed transformer according to claim 1, wherein the welded portion is welded such that a flat plate portion of the side plate overlaps an end portion of the embossed portion. The oil-immersed transformer according to claim 1, wherein the welded portion is welded to the flat portion of the side plate and the embossed portion. The oil-immersed transformer of claim 1, wherein the welded portion is welded to overlap end portions of the embossed portions of the side plates. The oil-immersed transformer according to claim 1, wherein the welded portion is welded to the end portion of the embossed portion of the side plate and the embossed portion. The oil-immersed transformer of claim 1, wherein the welded portion is welded in such a manner that one of the embossed portions of the side plates overlaps each other. The oil-immersed transformer according to any one of claims 1 to 6, wherein the embossed portion is used for positioning at the time of welding. The oil-immersed transformer according to claim 1, wherein the welded portion overlaps and welds the embossed portion of the side plate. The oil-immersed transformer according to claim 1, wherein the welding portion abuts the end faces of the side plates or overlaps the side plates to weld the end faces of the side plates. The oil-immersed transformer according to claim 1, wherein the plurality of embossed portions on the surface of the main body portion of the groove are convex portions or concave portions, and are continuously arranged in a side by side arrangement or a lattice arrangement. A method for manufacturing a groove of an oil-immersed transformer, characterized in that it is a method for manufacturing a groove of an oil-immersed transformer; and the groove is provided with a flange for mounting a cover, a bottom plate, and a flange disposed on the flange and the bottom plate a main body portion of the side plate; a plurality of embossed portions are formed on a surface of the main body portion; the embossed portion is formed by press working on the side plate; and the formed side plate is bent and formed; and the formed two side plates are formed The welded portions are welded to each other in such a manner that the embossed portions are stacked.