JPS598460B2 - Manufacturing method of corrugated fins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing corrugated fins for heat dissipation in transformers and the like.

In oil-immersed self-cooling systems such as oil-immersed transformers, the heat generated by the winding core is first transferred to the oil by convection, then to the tank wall, where it is dissipated from the outer surface of the tank wall by radiation and air convection.

In order to efficiently dissipate heat from the tank wall, the corrugated fins 1 are deep-drawn fins 1a into a corrugated shape as shown in Fig. 1.
is used. In order to process these corrugated fins from a flat plate, there is a method of performing deep drawing while applying two stages of wrinkle pressing pressure to the ribs using a mold, as a method with high productivity and high processing accuracy.

In particular, in order to reduce elastic deformation after removal from the mold after processing, it is necessary to give the material plastic deformation. Furthermore, a bag is formed by pressing both ends Ib of the protruding fin 1a of the corrugated fin 1 shown in Fig. 1 as shown in Fig. 2, and the seam Ic is welded. There were drawbacks such as the entire structure waving, being drawn in as in Id, or breaking as in Ie, and being difficult to process. The present invention creates corrugated fins by forming grooves parallel to the fins in the curved portion of the fins when forming the fins, so that when both ends of the fins are pressed, the grooves are stretched to prevent the material from deforming or breaking. The purpose is to provide a manufacturing method. Embodiments of the present invention shown in the drawings will be described below.

FIG. 5 shows the first step. In the figure, 1' is a material that is a flat plate before being processed into corrugated fins, 3 is a wrinkle pressing plate, 4 is a punch, and 5 is a die. When the material 1' is fed and supplied to a predetermined position, the feeding stops, and the wrinkle presser plate 3 descends to press the material. At this time, the wrinkle presser plate 3 and the die 5
A groove 2 is formed in the material. Next, the punch 4 descends and pushes the material 1' into the groove of the die 5 to form the fin 1a, and the material 1' is deformed in the groove 2 when passing through the wrinkle holding plate 3, so deformation resistance is added. , has the same effect as pressing with a large wrinkle pressing force. FIG. 3 shows the shape after the first step. FIG. 6 shows the second step.

In the figure, 1 is the corrugated fin after the first step, and 6 is the fin 1
T is a mold that presses the end of a, and T is a mold that presses the groove 2. When the material 1 is sandwiched and pressed by the molds 6 and 1, the ends of the fins 1a are crushed and at the same time the grooves 2 are crushed and flattened to fill the sink area of the fins 1a. Therefore, there is no strain on the material, so a product with less distortion can be obtained as a whole. FIG. 4 shows the shape after the second step. The shape and size of the groove 2 are determined by the amount of material drawn in when both ends of the fin 1a are pressed, the wrinkle pressing pressure, and the capacity of the press machine.

FIG. T and FIG. 8 respectively show other embodiments of the groove 2.
is provided on the rising portion of the fin 1a, and serves not only for the effect in the second step but also for reinforcing the fin 1a. Further, the grooves 2 may be either concave or convex, and a plurality of grooves may be arranged in parallel. As described above, according to the present invention, grooves parallel to the fins are provided in the curved portions on both sides of the fins of the corrugated fins, so that the pressure applied to the wrinkle presser plate in the first step of processing the corrugated fins can be reduced and the pressure applied to the wrinkle presser plate can be reduced. In addition to exerting a holding effect, in the second step of pressing both ends of the fins to bring them into close contact, the groove becomes flat and the material is drawn in, thereby preventing strain, deformation, or breakage of the entire material. Further, the grooves increase the section modulus of the fins, thereby increasing the rigidity, and increasing the surface area, thereby improving the heat dissipation effect.

If the direction in which the groove protrudes is toward the inside of the container, there is an effect that the amount of insulating oil, etc. can be reduced.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional corrugated fin after the first process processing, FIG. 2 is a perspective view showing the process shown in FIG. 1 after the second process processing, and FIG. 3 is an embodiment of the corrugated fin of the present invention. FIG. 4 is a perspective view showing the state after the second step in FIG. 3, FIG. 5 is a sectional view showing the state during the first step in FIG. 3, and FIG. 6 is a perspective view showing the second step of processing in FIG. 4, and FIG.
8 and 8 are cross-sectional views of corrugated fins showing other embodiments. 1... Waveform fin, 2... Groove, 3...
...Wrinkle presser plate, 4...Punch, 5...
...Die, 6,7... Mold.

Claims (1)

[Claims] 1 A first step of forming fins protruding in a wave shape from a flat plate and grooves parallel to the fins on the curved portions on both sides of the fins, and a second step of pressing both ends of the fins to bring them into close contact and welding. A method for manufacturing a corrugated fin, which consists of steps.