JPS5819123B2 - Manufacturing method of transformer case - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a transformer case in which a side wall of a case side plate is formed with radiation fins filled with insulating oil.

Conventionally, the configuration of the heatsink in the transformer case is the first one.
As shown in the figure, the open ends of the heat sink B, which are curved in a U-shape at the top and bottom of the case side plate, are welded to communicate with the inside of the transformer case, and the insulating oil is supplied through the heat sink B. As shown in Fig. 2, a metal strip is bent into a corrugated shape to form radiation fins C, and a plurality of these are arranged and welded around the outer circumference of the case side plate. Further, as shown in Fig. 3, a band-shaped metal plate is continuously bent into a wave shape at predetermined intervals to form a heat dissipation fin D, and the upper and lower ends of the heat dissipation fin D are closed by welding to insulate oil. A filling gap E is formed, and upper and lower side plates F and G are formed at both upper and lower ends of the gap E.
A transformer case is formed by welding and fixing the transformer case into a cylindrical body, and the gap E of the radiation fin D is filled with insulating oil to dissipate heat.

However, when forming a radiator with the heat radiating tube B,
Cutting the pipe 2 There are many heat dissipation members to assemble, such as bending both ends and attaching to case side plate A, and heat dissipation pipe B
Each of the tubes must be welded and fixed, which requires a large quantity of units, and it is also necessary to consider oil leakage at the welded portion of the heat dissipation tube B, making automation difficult.

In addition, when using a radiation fin C made by bending the strip material into a corrugated shape,
When painting, it is difficult to sufficiently coat the inside of the heat dissipation fin C, which may cause early deterioration of the transformer case due to rust. There is an opening to do so.

Furthermore, the heat dissipation fin D is made by continuously bending the band-shaped metal plate.
In the case of forming a heat dissipation fin D, the welded portions between both ends of the heat dissipation fin D and the upper and lower side plates F and G become long, which requires consideration for oil leakage, increases the number of welding steps, and increases the welding time. Since it is divided into upper and lower side plates F and G, there are problems in that the number of assembly steps is increased and automation is complicated and difficult.

The present invention has been made in view of the above-mentioned points, and its purpose is to provide a method for manufacturing a transformer case that improves the heat sink structure, makes the work easier, reduces man-hours, and facilitates automation. There is a particular thing.

Embodiments of the present invention will be described below with reference to FIGS. 4 to 6.

First, a case side plate 1 having a vertically long cylindrical shape is formed.

In this method, a band-shaped metal plate cut to a predetermined length is formed into a cylindrical shape by well-known roll processing, and both ends of the metal plate are butted or overlapped and fixed together by welding.

Since the joints at both ends are linear in this welding, it is possible to use a well-known automatic welding method that applies a welding torch to the joints at both ends from the outside and moves the welding torch in a straight line for welding.

At this time, if the primary and secondary bushings of the transformer are to be attached to the case side plate 1, the bushing attachment holes may be drilled in advance at predetermined positions and then rolled.

Next, heat dissipation fins 2 are integrally formed on the side wall of the case side plate 1. As shown in FIGS. A plurality of pairs of holding pieces 3a, 3a protruding in parallel are arranged vertically in the axial direction of the outer frame 3 at a predetermined interval, and a heat dissipation fin 2 is formed to bulge between the holding pieces 3a, 3a. A plurality of outer molding molds 4 are inserted into and removed from the outer frame 3 along the axis of the outer frame 3, projecting radially inward, and arranged in a circular pattern.

This molding outer mold 4 is formed vertically in the axial direction of the outer frame 3, and its head has the same arc as the outer peripheral arc of the cylindrical transformer case. A fin-forming recess 4a is provided in a vertically elongated manner.

A cylindrical inner frame 5 is concentrically housed inside the outer mold 4 and spaced apart from the outer frame 3, and the side wall of the inner frame 5 is provided with the mold 4 and the cylindrical inner frame 5. A plurality of suppressing inner molds 6 with opposing heads are installed so as to be freely extrudable radially.

This suppressing inner mold 6 is formed vertically in the axial direction of the inner frame 5, and its head has the same arc shape as the inner circumferential arc of the cylindrical transformer case, and the central part has the same shape as the bulging recess of the radiation fin 2. The fin extrusion part 6a is vertically stepped and is adapted to fit into the fin forming recess 4a of the outer mold 4 by the pressing movement of the inner mold 6 in the radial direction.

The outer frame 3 and inner frame 5 are each fixed on a base 7.

Further, as shown in FIG. 5, the back surface of the suppression inner mold 6 is inclined so as to extend downwardly toward the axis, and is formed into an inverted truncated cone or inverted truncated polygonal pyramid circumscribing this inclined surface. A cone-shaped extrusion member 8 is drivingly connected to a hydraulic cylinder 10 through a connecting rod 9 passing through the base 7 so as to be able to move up and down, and the downward movement of the extrusion member 8 simultaneously pushes the pressing inner mold 6 in the radial direction. A movable fin forming device forms a cylindrical case side plate 1 between the heads of the outer mold 4 and the inner suppressing mold 6.
is inserted with one open end in contact with the base 7, and the pressing inner mold 6 is simultaneously pressed and pushed in the radial direction toward the outer mold 4 by the downward movement of the extrusion member 8. The center part of the side wall of the case side plate 1 is the fin extrusion part 6 of the suppression inner mold 6.
The heat dissipating fins 2 are extruded in the radial direction by the heat dissipating fins 2a, and are compressed between the fin molding recesses 4a and the fin extrusion parts 6a, thereby forming the heat dissipating fins 2 in a bulging manner.

After that, the extrusion member 8 is moved upward to move the pressing inner mold 6 inward, and the case side plate 1 is extracted upward together with the outer mold 4, or the outer mold 4 is divided into upper and lower parts in advance. Then, the outer mold 4 is pulled upward together with the divided upper part, and the formation of the heat dissipation fins 2 on the case side plate 1 is completed.

As a result, as shown in FIG. 6, a radiator is formed in which a plurality of radiating fins 2 are arranged in the radial direction on the side wall of the case side plate 1, leaving short cylindrical side walls at the upper and lower parts.

In forming the heat dissipation fins 2, the side walls of the case side plate 1 are pressurized and extruded in the radial direction by the suppression inner mold 6, so after welding the joints at both ends of the case side plate 1 together, the heat dissipation fins are 2, tensile stress will be generated at the both end joints, but the case side plate 1 is inserted with the both end joints positioned in the middle of the outer mold 4°4, and the case side plate 1 is With respect to the circumferential direction of
The relationship between 1 and the bulging height H of the radiation fin 2 is L 1:26
The arrangement interval of the heat dissipation fins 2 is set to be H+ 40 (mm), and the distance L2 from the upper and lower ends to the rising edge of the heat dissipation fins 2 and the bulge height of the heat dissipation fins 2 are set in the vertical direction of the case side plate 1. The relationship between L2 and H is set as L2>3H (mm) (this reduces the tensile stress generated at both end joints, maintains sufficient welding strength, and reduces vertical shrinkage to dissipate heat. The fins 2 are formed into a bulge.

In addition, if you want to change the vertical length or width of the radiation fin 2 by attaching accessories such as bushings and oil level gauges to the case side plate 1, use the molding outer mold 4 and the suppression inner mold at the corresponding positions. 6 to the desired outer mold 4 and press inner mold 6 in advance, the length or width of the heat dissipation fins 2 at the corresponding location can be partially changed and expanded at the same time as the other heat dissipation fins 2. Can be formed.

Next, the bottom plate 11 is fixed by welding to one open end of the case side plate 1 on which the radiation fins 2 are formed.

As shown in FIG. 6, a bottom plate 11 shaped like a circular inverted dish is fitted into one open end of the case side plate 1 to form a so-called "raised bottom" and welded.

Since the open end of the case side plate 1 is circular, this welding can be performed by a well-known automatic welding method in which a welding torch is fixed to the arm, the torch is applied to the joint, and the arm is rotated while welding. becomes.

Then, the flange 12 is folded at the other open end of the case side plate 1 by applying pressure to the flange forming groove provided in a flange forming mold (not shown) and pressing the case side plate 1 toward the flange forming groove. By bending, the transformer Kenneth is formed.

In addition, in the example, the bottom plate 11 is welded and fixed, and the flange 12
Although it was explained that the pressure forming is performed after the heat dissipation fin 2 is formed, either one of the second steps is performed before the heat dissipation fin 2 is formed, and the heat dissipation fin 2 is formed using the fin forming machine with this process upward. It is also possible to make it grow.

In addition, in the embodiment, it has been explained that the pressing inner mold 6 for molding the heat dissipating fins 2 is pressed and moved by the cone-shaped extrusion member 8, but a link mechanism in which the extrusion member is drivingly connected to a hydraulic cylinder is used. Alternatively, it may be configured by an auxiliary hydraulic cylinder or the like.

According to the present invention, the case side plate is formed into a vertically elongated cylindrical shape, and the joints at both ends are butted or lap welded to form the cylindrical body, so that the joints at both ends are straight and welded. The heat dissipation fins can be arranged in a circular manner with a plurality of outer molds, and inside these, a plurality of heat dissipation fins are arranged in a circle with a plurality of outer molds arranged in a circular manner facing the outer molds. A cylindrical case side plate is inserted between the pressing inner mold, and a plurality of suppressing inner molds are pressurized simultaneously in the radial direction by an extrusion member to integrally form a bulge on the side wall of the case side plate. Since it is made of solid wood, multiple heat dissipation fins can be formed in one process, and when you want to change the vertical length or width of the heat dissipation fin because accessories such as bushings and oil level gauges are attached to the case side plate. In this case, it is recommended to change the setting of the molding outer mold and the suppressing inner mold at the relevant position in advance.
Therefore, a heat dissipation fin of a desired length and width can be formed to bulge at the same time as other heat dissipation lines, making it easy to change the heat dissipation fin, making it possible to increase efficiency and mass production. is integrally formed on the side wall of the case side plate leaving short cylindrical side walls at the top and bottom, so there is no need for welding to attach the heatsink to the case side plate as in the past, and the upper and lower side plates There is no need to weld the heat dissipation fins, so there is no deformation or distortion caused by the heat during welding, and there is no need to straighten the distortion, which greatly reduces work time and reduces the welding area. The welding length is also greatly reduced, so there is no need to worry about oil leakage from the welding area, and the bottom plate is attached by fitting and welding the circular inverted dish-shaped bottom plate into the open end of the case side plate, which has a circular opening. Since the welding part is circular, it is possible to automate welding, and the bottom plate is shaped like a circular inverted dish, so the legs attached to the bottom of the transformer case can also be attached to the bottom plate. The transformer case can be formed at the same time by removing the legs, and the number of parts and welding steps can be reduced, and the process for forming the transformer case can be easily automated.

In addition, the radiation fins are formed by forming the case side plate into a cylindrical shape and then integrally forming a bulge on the side wall of the case. Compared to conventional molding, the shaping process by work hardening is not required, making it easier to form a cylindrical shape, making it possible to form a transformer case with less variation in dimensions.Moreover, there are no heat dissipation fins on the side walls of the case side plate. The bulges are formed integrally; therefore, these function as reinforcing ribs, which makes it possible to use thin plate materials, making it easier to process the radiating fins into bulges, and improving the shape of the transformer case. It is also possible to reduce weight, and by forming a bulge on the heat dissipation fin, there are no edges (this makes it easier to paint, making it possible to achieve a uniform coating film, and simplifying the shape of the case and fins, making it possible to automate painting. This makes it possible to create a transformer case that significantly prevents rusting over a long period of time.

Furthermore, since there is no need to separately provide members for forming upper and lower side plates or a heat radiator, the number of members for forming the transformer case is significantly reduced, and material management can be rationalized.

Furthermore, the manufacturing process of the transformer case formed according to the present invention allows for various layouts, which facilitates the layout in terms of existing equipment and space, and improves the radiator structure to simplify the work and facilitate automation. This method has remarkable effects such as being able to easily and economically form a transformer case with reduced man-hours and improved productivity.

[Brief explanation of the drawing]

Figures 1 to 3 show examples of conventional Kava heaters.
Figure 1 is a vertical cross-sectional view of the main part showing the case using heat dissipation tubes, Figure 2
The figure is a perspective view of the main part showing the case where the strip material is made into a corrugated shape.
The figure shows a case in which a band-shaped metal plate material is bent into a corrugated shape, and Figure A is a vertical sectional view of the main part, and Figure 1 is a cross-sectional view taken along line X--X in Figure A. 4 to 6 show embodiments of the present invention, in which FIG. 4 is a plan sectional view of a main part explaining the formation of a bulge in the heat dissipation fin portion, and FIG. 5 is a longitudinal sectional view of FIG. 4. , FIG. 6 is a longitudinal sectional view of the transformer case. 1: Case side plate, 2: Radiation fin, 4: Outer mold, 4
a: fin molding recess, 6: pressing inner mold, 6a: fin extrusion section, 8: extrusion member.

Claims (1)

[Claims] 1 A band-shaped metal plate cut to a predetermined length is formed into a cylindrical shape, and both ends are welded to form a case side plate in the form of a vertically long cylindrical body with the top and bottom open. A plurality of fin molding recesses are arranged in a circular manner facing the mountain man ■, and a round molding outer mold is formed, and a vertically elongated stepped fin extrusion part is arranged in a circular shape on the inside of this molding outer mold, facing the fin molding recesses. A plurality of extrusion members are inserted between a plurality of molds and a pressing inner mold that can be simultaneously pushed in the radial direction,
The plurality of pressing inner molds are pressed simultaneously in the radial direction toward the outer molding mold, and the plurality of heat dissipating fins are formed on the side wall of the case side plate, leaving a short cylindrical side wall at the bottom and expanding them as one unit. A method for manufacturing a transformer case, characterized in that the transformer case is formed by molding the case side plate, fitting a circular inverted dish-shaped bottom plate into one open end of the case side plate, and melting the bottom plate integrally.