JPS6248363B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a method for forming a heat dissipation container having a large number of hollow fins through which insulating oil circulates, even if a thin metal plate is used. The present invention relates to a method of manufacturing a heat dissipation container for oil-filled electrical equipment such as a transformer tank, which can suppress deformation caused by welding and assembly.

(Prior art) Electrical equipment bodies have been becoming smaller and lighter in weight than ever before, but along with this, the containers that house the electrical equipment bodies are also required to be smaller and lighter.In particular, the metal plates that make up the containers The thickness is also extremely thin. However, when the plate thickness becomes thinner, deformation during assembly and welding is large, causing problems in terms of appearance and functionality. There was a limit to how far it could go.

In particular, heat radiating containers, such as those for transformers, require a radiator to dissipate heat generated during load, and the above restrictions are severe because they require a structurally complex assembly and welding process.

FIG. 4 is an example of a conventional oil-immersed transformer. The cylindrical body of the heat radiating container uses a heat radiating plate b having a large number of hollow fins a, a, and the inside of the hollow fins a, a of the heat radiating plate b is filled with insulating oil, so that the transformer is not operated. At times, oil circulates and radiates heat. This heat sink b
For economical reasons, a single strip-shaped thin metal plate is bent into a pulse wave shape at predetermined intervals to form a large number of fins, and both ends of each fin in the longitudinal direction are welded and closed. The heat dissipation plate b is then bent into a cylindrical shape, and both ends in the width direction are welded to side plates c, c made of thin metal plates that have been formed into a frame shape in advance to form the body of the heat dissipation container.

This welded portion is shown in FIG. One end edge of the side plate c is welded to the bottom plate to increase the rigidity of the side plate c, to form a sealing seat for sealing the tank when the side plate c forms the upper frame, and to form a bottom plate when the side plate c forms the lower frame. To make it easier, the flange part d
have. The wider the flange part d, the higher the rigidity, but if it is made too wide, the gap between the contents of the transformer and the inner wall of the tank will increase accordingly, which is not a good idea from the standpoint of miniaturization, and the current flange part d is The width is 10-20mm.

By the way, after welding the above structure, a large residual tensile stress is generated in the weld bead e and the weld side edge of the side plate c due to shrinkage due to temperature drop. This causes the side plate c to buckle and deform as shown in FIGS. 6 and 7. Needless to say, the amount of deformation is proportional to the amount of contraction of the weld bead and the edge of the side plate, and is inversely proportional to the rigidity of the side plate c. In particular, when welding thin metal plates, the amount of weld bead relative to the thickness of the plate is larger than that of thick plates, and the rigidity is conversely small, so the amount of deformation becomes significantly large. Partly because the width of the flange portion d cannot be made large, there is no means to prevent deformation. When such deformation occurs, correction requires a great deal of effort, and it becomes difficult to obtain a beautiful appearance. During welding work, workers are required to pay close attention to prevent the plates from melting through, and to maintain a high level of tension that does not allow even the slightest mistake in hand movement, which naturally affects work efficiency and productivity. decreases. Automation of welding is possible, but after the heat sink is bent into a cylindrical shape to form the body of the container to some extent, such welding requires large-scale equipment such as automatic tracing equipment, container rotation equipment, and container movement equipment. The amount of investment will be enormous.

(Problems to be Solved by the Invention) As described above, in consideration of the current situation where it has not been possible to reduce the size and weight of this type of container due to the large obstacles and inconveniences caused by making the constituent plates of the heat dissipation container thinner, the present invention has been developed. It is an object of the present invention to provide a method for manufacturing a heat dissipation container for oil-filled electrical equipment, in which the amount of deformation due to welding is extremely small and welding can be easily automated.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention bends a strip-shaped thin metal plate into a waveform at predetermined intervals to form a large number of fins. A heat sink is formed by welding both ends of each fin section in the longitudinal direction to form a hollow fin section, and cutting the hollow fin section to a predetermined length in the undulating direction. In a method for manufacturing a heat dissipation container for oil-filled electrical equipment in which a cylindrical body is formed by side plates made of thin metal plates constituting an upper frame and a lower frame, one end edge of each side plate made of thin metal plates is preliminarily coated. A flange portion is formed on each side plate, and the other end edge of each side plate made of thin metal plate and the end edge of the heat dissipation plate are aligned in a straight line or are stacked, and then the straight side plate is aligned. The abutting or overlapping portions are welded to form a joint plate, and then this joint plate is bent at several spaced locations with the hollow fins on the outside to form the body. .

(Function) Therefore, according to the present invention, the side plate and the heat sink, on which the flange portion is previously provided, are welded while being held in a straight line and then bent, thereby preventing deformation due to welding, welding distortion, and welding defects. This can be suppressed and welding can be easily automated.

(Example) Embodiments of the present invention will be described with reference to the drawings.

1 to 3, in the first step, a strip-shaped thin metal plate is bent into a pulse wave shape at predetermined intervals to form a large number of fins, and at the same time both longitudinal ends 1', 1 of each fin are bent. ' are automatically welded and closed to form a large number of hollow fin parts 1, 1 with voids inside.
form.

This is cut into a predetermined length in the undulating direction of the hollow fin portions 1, 1 to form the heat sink 2.

Next, in the second step, as shown in FIG. 1, for example, the heat radiating plate 2 is placed on rollers 3, 3 so that it can be transported. This may be a continuous step from the first step. Side plates 5, 5 made of thin metal plates cut to the same length as the heat sink 2 are attached to both sides of the heat sink 2 in the width direction. These side plates 5, 5 made of thin metal plates are used to constitute an upper frame and a lower frame, each having a flange portion 10 (second, second,
(see Figure 3) is formed in advance. This flange part 10 is used in the upper frame to increase the rigidity of the side plate 5 and to form a sealing seat for tank sealing, and in the lower frame to increase the rigidity of the side plate 5 and to facilitate welding of the bottom plate. It is something. The flange portion 10 of this embodiment is formed by bending one end edge of the side plate 5 to the side opposite to the protruding side of the hollow fin portion 1, and its width is set relatively so as not to increase the size of the tank. It is set small. Furthermore, notches 4, 4 are formed at required locations so as not to interfere with the bending of the heat dissipation plate 2 and side plates 5 in a later step. The edge part of the heat sink 2 and the edge part of the side plate 5 that does not form the flange part 10 are butted together, or the side plate 5 is slightly overlapped downward,
The abutting portions or overlapping portions are arranged in a straight line. Next, the heat radiating plate 2 and the side plates 5, 5 are transferred while being held by holding rollers 6, 6. Disposed near the holding rollers 6, 6 are the tips of stationary automatic welding torches 8, 8. The heat dissipating plate 2 and the side plates 5, 5 transferred at this position are continuously welded at the abutting or overlapping portions in a straight line from the tips by the torches 8, 8 while being transferred to form a joint plate. After welding, the side plates 5, 5 are subsequently straightened by straightening rollers 7, 7.

Next, in the third step, the joining plate produced in the second step is bent into a cylinder shape at the positions of the notches 4, 4 with the hollow fins 1, 1 outward, and both ends are welded to form the body. (See Figure 2). 11 is the welding line.

In addition, as a result of the above bending, the ends of the flange portions 10 located on both sides of the notches 4, 4 are abutted against each other, so these abutted portions are welded to connect the flange portions 10 that extend around the entire circumference of the body to each of the side plates 5, 5. to form. Thereafter, a bottom plate 12 is welded to a flange portion 10 formed on one side plate 5 of the cylindrical body to form a heat dissipation container.

In this way, the side plates 5, 5 constituting the upper frame and the lower frame are provided with flanges 10, 10 in advance, and the side plates 5, 5 are attached to both sides of the heat sink 2 having the hollow fins 1, 1. By making it possible to weld in a straight line and then assembling it into a cylindrical shape by bending, welding can be easily automated, welding deformation and distortion can be minimized, and thin metal plates can be used. becomes. That is, the side plates 5, 5
Since the flanges 10, 10 are provided in advance to increase rigidity, deformation of the side plates 5, 5 can be suppressed as much as possible when the heat sink 2 and the side plates 5, 5 are welded together. Furthermore, since the welding can be performed in a straight line on a flat plate, it is easy to automate the welding, and this automation allows welding without putting extreme stress on the operator. This results in
Since the side plates 5, 5 have the flange portions 10, 10, deformation is reduced, and welding distortion and welding defects can be reduced. In this case, as in the embodiment, the holding rollers 6, 6
Welding is performed while restrained by the straightening roller 7,
7, welding distortion etc. can be further reduced.

On the other hand, when welding both ends of a cylindrical joint plate or when welding the butt part of a notch, the same skill and tension as conventional thin plate welding is required, but since the welding length is relatively short, there is no problem. Also, since it is a simple welding line, it is easy to automate.

[Effects of the Invention] As described above, according to the method of the present invention, the side plate with the flange portion provided in advance and the heat sink are welded while being held in a straight line and then bent, thereby preventing deformation due to welding, welding distortion, It has excellent effects in that it is possible to suppress the occurrence of welding defects, and it is also possible to automate welding with a much smaller investment compared to conventional welding automation equipment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the method for manufacturing a heat dissipation container according to the present invention, FIG. 2 is a perspective view of a heat dissipation container for a transformer manufactured by the same method, and FIG. 3 is a diagram showing the formation of a flange portion during manufacturing. Figure 4 is a front view of a conventional oil-immersed transformer, Figure 5 is an enlarged sectional view taken along the line X-X in Figure 4, and Figure 6 is a welding strain occurring in the same area. FIG. 7 is a cross-sectional view showing a state in which the welding is caused, and FIG. 7 is a perspective view showing a state of welding distortion. DESCRIPTION OF SYMBOLS 1... Hollow fin part, 2... Heat sink, 3... Roller, 4... Notch, 5... Side plate, 6... Holding roller, 7... Straightening roller, 8... Automatic welding torch, 10 ... Flange part, 11 ... Welding line, 12
……Bottom plate.

Claims (1)

[Claims] 1 A strip-shaped thin metal plate is bent into a waveform at predetermined intervals to form a large number of fins, and both ends of each fin in the longitudinal direction are closed by welding to form a hollow fin. A cylindrical body is formed by a heat dissipation plate cut to a predetermined length and side plates made of thin metal plates that are fixed to both widthwise ends of the heat dissipation plate and constitute an upper frame and a lower frame. In the method for manufacturing a heat dissipation container for oil-filled electrical equipment, a flange portion is formed in advance at one end edge of each thin metal plate side plate, and the other end edge of each thin metal plate side plate and the heat dissipation plate are formed in advance. The end edges of the hollow fins are aligned in a straight line or overlapped, and then the straight butted or overlapping parts are welded to form a joint plate, and then this joint plate is attached to the hollow fin part. A method for producing a heat dissipation container for oil-filled electrical equipment, characterized in that the body is formed by bending the outside at several locations at intervals.