JPS6160217A - Formation of thin metallic sheet - Google Patents

Abstract

PURPOSE:To form easily a high rising wall-hole by forming radial cuts, cut radially based on the center of a rising wall-hole to be provided to a thin metallic sheet, before rasing all together plural tongue-pieces divided by the cuts. CONSTITUTION:Four lines of cuts 11A are formed by a punch 12 and a die 13. Next, new four lines of cuts 11B are formed between the four-lines of cuts 11A by a punch 12' and a die 13', to form plural sectorial tongue-pieces 14 between the cuts. Next, a rising wall-hole 3 having a rising wall 4 consisting of tongue-pieces 14 is formed by bending each tongue-pieces 14 from its base-end part, to raise the piece 14 to the sheet-surface side of one side of a thin metallic sheet, by using a die 15 and a punch 16 used for burring work, before forming a flare part 5 by bending the front end of wall 4 to the outside by using a punch 17 used for flaring work. Accordingly, the yield of product is improved without performing piercing work.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a raised wall having a raised wall (collar) on the inner periphery, such as a hole for inserting a tube in an aluminum alloy fin plate of a heat exchanger. The present invention relates to a method for forming holes in a thin metal plate.

2. Description of the Related Art Generally, in a fin plate type heat exchanger, as shown in FIG. 7, a fin plate 1 made of an aluminum alloy or the like is made of copper or aluminum alloy, through which a cooling medium or a heating medium, such as Freon, flows. It is necessary to form an upright wall hole 3 for inserting the tube 2 made of aluminum. The rise in this rising wall hole 3! (partially empty) 4
The fin plate 1 is brought into close contact with the tube 2 to improve heat conduction from the tube 2 to the fin plate 1, and at the same time, the height of the collar portion 4 allows the fin plate 1A to be in close contact with the other fin plate 1A adjacent in parallel. It also plays a role in regulating spacing. The tip of the collar portion 4 is usually processed to form a flared portion 5 with a curved cross section in order to prevent other fin plates 1A from getting caught and to provide strength. be.

Conventionally known processing methods for forming the upright wall holes 3 of the fin plate 1 as described above include (a) one-way drilling method, (b) burring method, and (c) ironing method.

For example, the draw one method of (A) above is shown in FIGS. 8(A) to (F).
), first stretch forming (A) is performed, followed by several stages of re-drawing (B) and (C), then piercing (D), followed by burring (
A part of the collar is formed by E), and finally a flared part is formed by flaring (F). In addition, the burring method described in (b) above can be used, for example, in FIGS.
As shown in C), a hole is first made by piercing (A), followed by burring (B) and flaring I (C). Furthermore, as shown in FIGS. 10(A) to 10(D), the ironing method (c) is similar to the burring method in that the piercing process (A) is performed.
and burring processing (B), and then ironing processing (C) to thin the tip of a part of the collar,
Finally, flaring processing (D) is performed.

All of these processing methods have piercing, burring, and flaring in common, and the drilling in these processes is important because it determines the height of the empty part and the spacing between adjacent fin plates. This is a contributing factor.

In addition, as a processing method that partially changes the one-way method, after performing stretch forming, redrawing, and piercing, a hole 6 formed by piercing is formed as shown in FIG. 11.
The method of forming four cuts 7 around the periphery and then performing burring and flaring is described in Japanese Patent Publication No. 57-2.
This is proposed in Publication No. 0043.

Problems to be Solved by the Invention In all of the above-mentioned drilling method, burring method, ironing method, and the 31 method disclosed in Japanese Patent Publication No. 57-20043, drilling by piercing is an essential step. However, during piercing process, circular or oval shaped scraps accumulate in the mold,
If this is left untreated, it will clog the inside of the mold and cause mold cracking and mold damage.Also, since this punched scum is coated with molding oil, it tends to adhere to the inside of the press and the mold. Conventionally, the work of removing the scraps by hand has been carried out periodically, but this work requires manpower, which poses a problem of increasing operating costs and lowering productivity.

Moreover, the punched scraps from the piercing process as described above naturally result in material loss, resulting in a decrease in yield.

In addition, the aforementioned (a) doro one-way method, (b) barring method,
(B) In all ironing methods, the ability to expand the bow during burring is an important factor that determines the height of the part of the collar, but with ironing, there is a limit to the ability to expand the hole in one hole. However, there are few aluminum alloys in which the maximum pore expansion rate exceeds 50%, and therefore there is a drawback that the height is partially limited.

The present invention has been made against the background of the above-mentioned circumstances, and provides a method for forming a rising wall hole in a thin metal plate, which does not generate scraps and can easily obtain a rising wall hole with a partially high height. The purpose is to

Means for Solving the Problems The metal thin plate forming method of the present invention provides a rising wall hole having a wall rising to one side of the plate surface at the inner peripheral edge of the hole.
When forming it into a board, gold 1! [Multiple cuts are formed in the thin plate radially extending from a position corresponding to the center of the upright wall hole to be finally formed, and then the above-mentioned 8
This method is characterized in that a rising wall hole is formed by simultaneously raising each tongue portion divided by a cut using a die and a punch.

Detailed explanation for carrying out the invention In carrying out the method of this invention, first the method shown in FIG.
As shown in A) or (B), gold 11il such as aluminum alloy N plate to be the fin plate of the heat exchanger
A plurality of linear cuts 11 are formed in the plate 10 radially (that is, in the radial direction) with reference to position 0, which is the center of the rising wall hole 3 to be finally obtained. Cut point 1 here
As will be described later, it is desirable to set the number of 1s to 5 or more (Fig. 1 (A)).
B)) is desirable.

As a specific method for forming the plurality of radial cuts 11 as described above, for example, they may be formed by shearing using a die and a punch. For the second example
As shown in Figures (A) and (F3>), a punch 12 having a tip surface shaped like two quadrants symmetrically butted together as shown in Figure 2 (A) and a die 13 corresponding to the punch 12. As shown in FIG. 2(B), using a punch 12- and a die 13- which have the same shape as described above and are shifted in phase by 45 degrees with respect to the position shown in FIG. 2(A), first, the second
Figure 3 (Figure 3) by punch 12 and die 13
As shown in FIG. 3(B), four cuts 11A are formed at 90' intervals, and then, as shown in FIG. It is sufficient to form the book cut 11B.

A plurality of radial cuts 11 (11A, 1
1B), a plurality of fan-shaped tongue pieces 14 are formed between them. Therefore, in the next step, for example, as shown in Figure 3 (
As shown in C), each tongue portion 14 is bent from its base end portion and raised toward one plate surface side of the thin metal plate 10. In this way, a rising wall hole 3 having a rising wall (collar) 4 made of the tongue portion 14 is formed.

As a specific means for bending and raising the tongue portion 14 in this manner, for example, a burning die 15 and a punch 16 may be used as shown in FIG.

After forming the rising wall hole 3 as described above, the fifth hole is usually formed.
Using a punch 17 for flaring as shown in the figure, a flaring process is performed to curve the tip of the rising edge 14 made of a portion 14 of the tongue piece 7 outward as shown in FIG. 3(D). Section 5 is formed.

In the above explanation, if the number of linear cuts 11 formed in the thin metal plate 10 is four or less than four, the tongue portion 14 will break at the bent portion when being raised (burring). There is also a possibility that the adhesion with the tube may be reduced or the commercial value in terms of appearance may be reduced. In order to avoid such problems, it is desirable that the number of cuts 11 be 5 or more. /
It is desirable to have eight or more.

Note that the method of the present invention can also be used in combination with the conventional slurry method described above. That is, gold i [After performing overhang forming on the thin plate 10 and re-drawing as necessary, the top surface 1 of the overhanging portion is formed as shown in FIG. 6(A).
A plurality of cuts 11 are formed in 7, and then Fig. 6 (8)
As shown in the figure, burring is performed to make each tongue portion 14 stand up, and then flaring is performed as necessary.

Furthermore, in the above explanation, it was assumed that the flaring process was finally performed, but it may be omitted depending on the case. In other words, flaring processing is normally required when forming fin plates for heat exchangers, but the method of this invention can be used not only for fin plates for heat exchangers but also for tubes! 5
The rising wall hole for mounting in the w state is made with gold i['fII
The present invention is applicable to all cases in which it is formed into a plate, and in applications other than fin plates for heat exchangers, it may be used without flaring.

Effects of the Invention In the method of the present invention, a rising wall (collar) is formed by forming a plurality of linear cuts 11 in a thin metal plate 10 and making fan-shaped tongue portions separated by the cuts 11 stand up. From forming a rising wall hole with
Since there is no need to perform piercing, and therefore no punching residue from piercing remains in the mold, there is no need to remove the punching debris, and participation is improved. In addition, in the method of the present invention, the height of the collar part is mainly determined by the length of the tongue formed by the cut, and the height of the collar part is not controlled depending on the hole expandability of the material. It is possible to obtain a part of the collar with a height that is, for example, twice as high as that of the conventional burring method.

[Brief explanation of drawings]

FIGS. 1(A) and (B) are plan views showing aspects of the cuts formed by the method of the present invention, and FIGS. 2(A) and (B) respectively.
is a schematic perspective view showing an example of a die and punch used in the step of forming a cut in the method of the present invention,
3(A) to 3(D) are perspective views showing step-by-step an example of the method of the present invention, and FIG. 4 shows a die and punch for burning to raise the tongue portion in the method of the present invention. FIG. 5 is a schematic perspective view showing a punch for flaring to finally form a flared portion in the method of the present invention, and FIG.
A>, (B) is a diagram showing a part of the process when the method of the present invention is used in combination with the dross method. FIG. 7 is a vertical cross-sectional view showing a conventional normal upright wall hole in a fin plate of a heat exchanger, and FIGS. 8 (A) to (F) are schematic diagrams showing step-by-step the conventional drawer type. Figure 9 (A) ~
(C) is a schematic diagram showing the conventional burring method step by step, Figures 10 (A) to (D) are schematic diagrams showing the conventional ironing method step by step, and Figure 11 is a schematic diagram showing the conventional ironing method step by step. It is a perspective view for explaining an example of a conventional method. 3...Rising wall hole, 4...Rising! (partially empty)
, 10... metal thin plate, 11.11A, 11B...
Cut, 14... tongue piece part. Applicant Sky Aluminum Co., Ltd. Agent Patent Attorney ± 11) Hisashi Take (one idiot) 3rd podium 7'F Figure 4, 5° 6th illustration) (B) Condolences t 4 Figure 11 Figure 8 (A) ) C===-1 Figure 9 (A) - 11111 Figure 10 (A)

Claims (3)

[Claims] (1) When forming a rising wall hole in a thin metal plate, which has a wall rising to one side of the plate surface on the inner peripheral edge of the hole, the position corresponding to the center of the rising wall hole to be finally formed in the thin metal plate is used as a reference. A thin metal sheet characterized in that a plurality of cuts extending radially are formed, and then each tongue section divided by each cut is made to stand up all at once using a die and a punch to form a rising wall hole. Molding method. (2) The method for forming a thin metal sheet according to claim 1, wherein the number of cuts is five or more. (3) The method for forming a thin metal sheet according to claim 1, wherein the number of cuts is eight or more.