JPS6237802B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a tank for oil-filled electrical equipment, such as a transformer, which has fin-like protrusions with a large heat dissipation effect.

There are various types of tanks for oil-filled electrical equipment, and the one shown in FIG. 1 is one of them. 1st
Figure a is a longitudinal cross-sectional view of the main part of a conventional tank for oil-filled electrical equipment with fin-like overhangs, b is a side view, and c is figure a.
It is a cross-sectional view taken along line AA of FIG. In the figure, 1 is a corrugated plate that constitutes the side wall of the tank.The steel plate is formed by extrusion into a corrugated shape with wave crests that are taller than the width, and then the upper and lower ends of each crest are squeezed inward. A fin-like projecting portion 4 whose upper and lower ends 2 and 3 are closed by welding the butt portions.
A large number of them have been formed. This corrugated plate 1 is welded to a tank top 7 and a tank bottom 8 at both ends 56 of its troughs to form a tank. The insulating oil 9 in the tank also fills the fin-like projections 4 of the corrugated plate, and when the transformer is operated, oil convection occurs as shown by the arrow 10, dissipating heat from the wide surface of the fin-like projections 4. Dissipate.

This tank structure has a larger heat radiation area and has a shorter weld line than other conventional tank structures, such as those that use a panel heat radiator made of two stacked molded panels and welded edges. Although it is advantageous in terms of productivity, the fin-like overhangs 4 in this tank structure are arranged side by side at narrow intervals by extrusion molding, so unlike panel-type radiators,
A reinforcing bead is provided vertically on the side surface 11,
It is not possible to take reinforcement measures that require secondary processing of the side parts 11 themselves, such as bringing both side parts 11 partially close to each other and welding them directly, and conventionally, there is no specific technique for reinforcing the fin-shaped overhanging parts 4. Ta.

For this reason, changes in tank internal pressure during transformer operation,
In particular, due to the large internal pressure applied when an internal accident occurs, the side surface 11 of the fin-like overhang 4 is deformed as shown by the dotted line 11 in FIG. There is a risk that the welds near the boundaries between the upper and lower ends and the tank top 7 and tank bottom 8 will peel off, causing oil leakage, and the only way to prevent this is to increase the thickness of the corrugated plate 1.

The present invention increases the pressure resistance of the fin-like projections and has fin-like projections that have a large heat dissipation effect without increasing the weight of the tank or causing difficulty in corrugation due to thickening of the corrugated plate. The purpose is to economically manufacture tanks for oil-filled electrical equipment, and in order to achieve this, the reinforcing member of the fin-like overhang is formed so that it can be attached to a welding electrode,
This reinforcing member attached to a welding electrode is inserted inside the fin-shaped overhang, and the welding electrode with this reinforcing member attached is connected to another electrode located outside the fin-shaped overhang. The present invention proposes a method of manufacturing a tank for oil-filled electrical equipment, characterized in that the reinforcing member and both side surfaces of the fin-shaped overhang are joined by resistance welding.

Figure 2a is a vertical cross-sectional view of essential parts showing an example of a tank for oil-filled electrical equipment manufactured according to the present invention, and Figure 2b is a longitudinal cross-sectional view of the essential parts.
A sectional view taken along the line BB of FIG.

In FIG. 2, the structure of the corrugated plate 1 itself and its manufacturing method are the same as those described in FIG. 1, and the same reference numerals as in FIG. 1 indicate the same parts. The reinforcing member is inserted inside the fin-like projection 4 of the corrugated plate 1, and both side surfaces 11 of the fin-like projection 4 are inserted into the reinforcing member 12.
are partially joined by resistance welding.
13 indicates the joint. It is preferable that the reinforcing member 12 has an elongated shape in the vertical direction of the tank as shown in the figure, and is arranged vertically with both ends separated from the upper and lower ends 2 and 3 of the fin-like projecting portion 4. With this structure, not only can the fin-shaped overhanging portion 4 be sufficiently reinforced against internal and external pressure, but also the reinforcing member 12 can also be used as a rectifying plate that guides oil flow as shown by arrow 10' during transformer operation. This has the effect of promoting convection of the insulating oil 9 in the tank and assisting heat radiation. Although FIG. 2 shows an example in which only one reinforcing member 12 is used, two or more reinforcing members 12 may be arranged in parallel.

The reinforcing member 12 has a cross-sectional shape suitable for attachment to a welding electrode in order to facilitate welding work as described later, for example, as shown in FIG. It is desirable to form it into a trough shape with a U-shaped cross-section as shown.

If such a reinforcing member with a U-shaped cross section is used, the oil flow path in the fin-shaped overhang 4 will not be narrowed, unlike when the both side surfaces 11 are partially brought close together and directly welded.

Next, a method for partially joining and reinforcing both side surfaces of the fin-like overhang using this U-shaped cross-section reinforcing member will be specifically described. As shown in Figure 2c,
The reinforcing member 12 is a welding electrode 14 formed into a plate shape.
The arm-shaped electrode 16 of the welding machine, which is inserted and positioned into the fin-shaped extension 4 from the direction of arrow 15, is placed over the tip of the fin-shaped extension 4, and is placed along the side of the fin-shaped extension 4. After moving it in the direction of and setting it at the welding position, the workpiece 11,
12 is sandwiched and pressurized in the direction of arrow 18 while applying electricity from a power source 19 to join by resistance welding. The fin-shaped protruding portion 4 may be sandwiched between two arm-shaped electrodes 16 to join both side portions 11 at the same time, or the electrodes 14 may be used as back electrodes for welding by an indirect method. By using the above method, it is possible to easily join the reinforcing member 12 located inside the narrow and deep fin-shaped overhang 4 to the both side surfaces 11.

The thus reinforced corrugated plate 1 is welded to a tank top 7 and a tank bottom 8 at both ends 5 and 6 of its troughs to construct a tank.

As explained above, according to the present invention, since both side surfaces of the fin-like overhang are firmly joined via the reinforcing member inserted inside the fin-like overhang, the extruded fin-like The fin-like projecting portion can be sufficiently reinforced against internal and external pressure without the need for performing secondary processing on both side surfaces of the projecting portion themselves.

Therefore, without increasing the thickness of the corrugated plate, it is possible to manufacture a tank for oil-filled electrical equipment that has a sufficiently high wave crest height and a fin-shaped overhang with a large heat dissipation area, making the equipment smaller and lighter. can do. In particular, in the present invention, the reinforcing member attached to the welding electrode is inserted inside the fin-like overhang, and the welding electrode with the reinforcing member attached and another electrode located outside the fin-like overhang are connected to the reinforcing member attached to the welding electrode. Since the reinforcing member and both side surfaces of the fin-like overhang are joined by resistance welding, the reinforcing member inserted inside the narrow and deep fin-like overhang can be securely positioned. At the same time, by applying an appropriate pressure to the welding point between the electrode on which the reinforcing member is attached and the outer electrode, welding between the reinforcing member and both sides of the fin-shaped overhang can be easily performed in a short time. This method has a unique effect in that a corrugated tank having a fin-like overhang having high pressure resistance can be manufactured economically.

[Brief explanation of the drawing]

Figures 1a, b, and c are longitudinal cross-sectional views, side views, and AA cross-sectional views of the main parts of a conventional oil-filled electrical equipment tank with fin-like overhangs, and Figures 2a, b, and c are from this FIG. 1 is a longitudinal sectional view of a main part, a BB sectional view, and an explanatory diagram of a manufacturing process, showing an example of a tank for oil-filled electrical equipment manufactured according to the invention. DESCRIPTION OF SYMBOLS 1... Corrugated plate, 2, 3... Upper and lower ends of the fin-like protrusion, 4... Fin-like protrusion, 5, 6... Both ends of the trough of the corrugated plate, 7... Tank top, 8... Tank bottom, 11 …
Both side surfaces of the fin-like overhang, 12... reinforcing member, 13
. . . Joint portion between both side portions and reinforcing member, 14 . . . Welding electrode, 16 . . . Other electrodes.

Claims (1)

[Claims] 1. When manufacturing a tank for oil-filled electrical equipment in which the tank side wall is made of a corrugated plate having a fin-like overhang with closed upper and lower ends, the reinforcing member of the fin-like overhang can be attached to a welding electrode. The reinforcing member is attached to a welding electrode and inserted inside the fin-like protrusion, and the reinforcing member is attached to the welding electrode and the reinforcing member is inserted outside the fin-like protrusion. A method of manufacturing a tank for oil-filled electrical equipment, characterized in that the reinforcing member and both side surfaces of the fin-shaped overhang are joined to another electrode by resistance welding.