JPS6156605B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tank for oil-filled electrical equipment such as a transformer, and has a side plate formed by bending a sheet-like thin steel plate into a corrugated shape to form a fin-like protrusion. This invention relates to a tank for oil-filled electrical equipment having a structure in which a secondary bushing is provided on the side wall of the tank.

Generally, in oil-filled electrical equipment, heat generated inside the equipment is radiated from the tank surface using insulating oil as a medium. For this reason, various structures have been adopted for tanks of oil-filled electrical equipment to enhance the heat dissipation effect. Among these, corrugated heat dissipation plates, in which a sheet steel plate is bent into a corrugated shape to expand the heat dissipation area, have come into widespread use. As shown in FIG. 1, this corrugated heat dissipation plate is made by bending a thin sheet-like steel plate 1 into a wave shape to form fin-like protrusions 1a at regular intervals, and attaching the tips of the protrusions 1a to a plurality of reinforcing pieces 2. Thus, they are connected to each other, and the upper and lower edges of each of the protrusions 1a are pressed together and welded, for example, by MAG welding, to form a single corrugated heat sink 3. However, when a corrugated heat sink is used to construct a tank for oil-filled electrical equipment, the upper and lower edges of the corrugated heat sink are fixed to the upper side plate and the lower side plate/bottom plate of the tank by welding or the like. The tank side wall is constructed. In a tank structure using such a corrugated heat sink, when the bushing is attached to the side wall of the tank, a tank structure as shown in FIG. 2 is adopted. Here, 3 is a corrugated heat sink forming two opposing sides of the tank side wall, 4 is an upper side plate, 5 is a bushing attached to the remaining two sides of the tank side wall, and 6 is a cable duct surrounding the bushing 5. . This structure can be applied to devices that generate little loss, but as the capacity of the device increases, the heat dissipation area must naturally be increased, and in this case, the amount of protrusion of the protruding portion 1a will be increased. However, the stress caused by the tank pressure of the protruding portion 1a occurs in proportion to the amount of protrusion, that is, the square of the wave depth, and inversely proportional to the square of the plate thickness, and the amount of deformation is proportional to the fourth power of the wave depth. However, since it increases or decreases in inverse proportion to the cube of the plate thickness, it is necessary to increase the plate thickness according to the size of the protrusion in order to suppress the stress and deformation of the protrusion 1a to below the respective allowable values. Naturally, as the thickness of the plate increases, the cost of materials and the weight of the product increase. Furthermore, in the structure in which the heat sink 3 is arranged on three sides of the tank side wall as shown in FIG. A dead space is created outside the sides, that is, outside the corners of the tank, which increases the external dimensions of the device. In addition, it is necessary to provide the protrusions 1a at an appropriate pitch from the viewpoint of heat dissipation efficiency. Therefore, the total number of protrusions can be limited depending on the tank size, and the amount of protrusion of the protrusions 1a can be set in order to obtain a larger amount of heat dissipation. Naturally, even if the number of the bushings is increased, there are manufacturing limitations, and there are also problems with the strength of the protruding portion 1a mentioned above, so the above-mentioned structure is inconvenient in the case of the bushing lateral extension method.

The present invention was made in view of these points,
To provide a tank for oil-filled electrical equipment of a side-extruding bushing type, which is small, lightweight, and economical, has high mechanical strength, can enlarge the heat radiation area without increasing the plate thickness of the fin-like protruding parts.

An embodiment of the present invention will be described below with reference to FIGS. 3 to 11. In FIG. 3, the tank for oil-filled electrical equipment according to the present invention has a pair of short side walls 1 which are arranged opposite to each other and are constructed of corrugated heat sinks.
1, 11, and a flat long side wall 1 disposed between the opposing ends of the pair of short side walls 11, 11.
2 and 12 are oil-tightly fixed at their adjacent ends by welding or the like to form a tank side wall.
In this case, both ends of the pair of short side walls 11, 11 are connected to the base 12 of each long side wall 12, 12.
The base portions 12a, 12 of the long side walls 12, 12 are arranged at positions extending outward from the positions of the long side walls 12, 12a.
Attach the bushings 5, 5 to a. Note that 6 indicates a cable duct that covers the bushing 5.

FIG. 4 is a plan cross-sectional view of a corrugated heat sink forming the short side wall 11 of the tank, in which fin-like protrusions 1a are formed continuously at regular intervals by bending a sheet-like thin steel plate in a corrugated manner. A plurality of flange parts 1b, 1b are formed to form a protruding part group, and a flat plate part is provided at both ends of the protruding part group, and the flat plate part is appropriately bent and welded to another adjacent side plate. was formed. The upper and lower edges of each protrusion 1a of the corrugated heat sink 11 are pressed together and oil-tightly fixed by welding. Further, the tips of the respective protrusions 1a of the protrusion group are connected to each other by reinforcing pieces 2, and the side without the reinforcing pieces 2 is disposed inside the tank.

On the other hand, FIGS. 5a to 5c show the long side wall 1 of the tank.
2 is a plan view, a front view, and a side view of a flat plate constituting the base 1.
Side plate parts 12b, 12b are formed on both sides of the base 12a, and the ends of the side plate parts 12b, 12b are further bent to form flange parts 12c, 12c.
In the middle part of a is an opening 1 for attaching a bushing.
2d is provided. The base portion 12a of this flat plate is placed inside the tank.

A tank side wall is constructed by fixing the respective flange portions 1b, 12c of the pair of short side walls 11, 11 and the pair of long side walls 12, 12 by welding.

Note that FIGS. 6a to 6d show various connection structures at the flange portions of the long side wall 12 and the short side wall 11.

As shown in FIGS. 7 and 8, the upper side plate 15 and the lower side plate/bottom plate 16 are fixed to both the upper and lower ends of the tank side wall configured as described above, and the short side walls 11, 11 and the long side side wall 12,
The communication path 1 shown in FIG. 3 formed between the
Cover plates 18 and 19 (see FIG. 8) are fixed to the upper and lower parts of 7 and 17 by welding to form one tank.

The tank for oil-filled electrical equipment constructed in this manner has the following advantages. That is, first of all, from the point of view of downsizing the equipment, it is not possible to form fin-like protrusions on both sides of the cable tact provided on the side wall of the tank in tanks using conventional corrugated heat sinks, but in the present invention, as shown in FIG. As shown in the plan view shown in FIG. The protruding portion 1a can also be formed in the heat dissipation support, so that it is possible to reduce the external dimensions of the device, that is, to reduce the floor space.

In addition, in tanks using conventional corrugated heat sinks, depending on the amount of heat generated by the equipment, if the amount of heat generated is large, the protrusion 1a
The amount of protrusion is increased to increase the heat dissipation area, but this amount of protrusion, that is, the depth of the waves, is naturally limited by manufacturing limitations such as the capacity of manufacturing equipment or the processing accuracy of the product in waveform shaping and squeeze molding of both edges. In addition, in order to obtain effective heat dissipation characteristics on the air side, the pitch of the protrusions is also limited depending on the depth of the waves, and the number of protrusions is also limited for the same tank size. Therefore, in such a tank structure, the maximum amount of heat dissipation is limited and the applicable equipment capacity is limited.

In addition, if the depth of the waves is increased depending on the amount of heat generated, both stress and deformation must be kept below the allowable values for the internal pressure of the tank, but as the depth of the waves increases, it is natural that The board thickness must be increased depending on the depth.

On the other hand, the tank structure according to the present invention can be formed by providing the protrusions 1a on both sides of the cable duct 6 to increase the total number of protrusions 1a, as described above, so that the amount of stress and deformation of the protrusions 1a due to tank internal pressure can be increased. It is easy to reduce the temperature below the allowable value without increasing the plate thickness, reducing material costs and reducing the weight of the product compared to conventional tank structures. The applicable equipment capacity of the structure can be greatly expanded.

In the above embodiment, the long side walls 12 were constructed of flat plates bent in a U-shape, but as shown in FIG. 22, 22, and an end portion 22e of each long side wall 22, 22 without a side plate portion,
If the corrugated heat radiating plates 25, 25 are connected between 22e and the end of the short side wall 11, the number of fin-like protrusions increases, so the heat radiating capacity can be increased. In this case, the bushing 5 attached to the intermediate portion of the long side wall 22 is disposed offset from the center of the intermediate portion toward the side plate portion 22b.

In addition, as shown in FIG. 10, in order to further increase heat dissipation capacity, flange portions 32c, 32c are provided at both ends.
The long side wall 32 is made up of a flat plate formed with only one side, and the corrugated heat sinks 35, 35 are connected between both ends of the long side wall 34 and the ends of the short side walls 11, 11, respectively. I can do it.

Furthermore, as shown in FIGS. 11a to 11c, when the long side wall 42 is constructed of a flat plate bent into a U-shape,
It is also possible to form bag-shaped portions 42e that project outward and extend in the height direction on the side plate portions on both sides. With this configuration, the occurrence of small loops in the natural circulation of the insulating oil inside the heat sink can be eliminated, and the cooling efficiency of the oil side of the equipment can be improved.Moreover, the rigidity is increased, making it possible to reduce the board thickness. This makes it possible to further reduce the weight of the equipment.

As explained above, in the present invention, compared to a tank structure configured using a conventional corrugated heat sink, it is possible to downsize the equipment, and in the case of a tank with the same amount of heat dissipation as a conventional tank, the plate thickness is reduced. Thus, it is possible to obtain an oil-filled tank for electrical equipment that has effects such as reduction in material costs and weight reduction of the product.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a corrugated heat sink, Fig. 2 is a plan view showing a conventional tank for oil-filled electrical equipment, and Fig. 3 is a plan cross section showing an embodiment of the tank for oil-filled electrical equipment according to the present invention. Figure 4 is a plan sectional view showing the short side wall of the oil-filled electrical equipment tank shown in Fig. 3, and Figs. Sectional view, front view and side view, Figure 6a
to d are cross-sectional views showing various connection structures between the short side walls and the long side walls, and Figures 7 and 8 are the oil-filled electrical equipment tank shown in Figure 3 with the upper side plate and lower side plate/bottom plate attached. 9th plan view and side sectional view showing
10 and 10 are plan sectional views showing other embodiments of the present invention, respectively, and FIGS. 11a to 11c are plan sectional views, front views, and side sectional views showing other embodiments of the long side walls. 1... Sheet steel plate, 1a... Protrusion, 2...
Reinforcement piece, 5... Bushing, 11... Short side side wall,
12, 22, 32, 42...long side wall, 12a...
…base.

Claims (1)

[Claims] 1. Fin-like protrusions are continuously formed by bending a sheet steel plate in a corrugated manner, and a pair of corrugated heat dissipating plates with both ends of each fin-like protrusion fixed in an oil-tight manner are placed at a predetermined interval. A flat plate having an opening for attaching a bushing is arranged between the ends of the pair of short side walls to form opposing short side walls, and the adjacent ends are oil-tight directly or through another member. The long side walls are formed by being fixed to the long side walls, and both ends of each of the pair of short side walls are arranged at an extended position outward from the base of the pair of long side walls. A tank for oil-filled electrical equipment.