JPH05169172A - Manufacture of fin for heat exchanger - Google Patents

Abstract

PURPOSE:To obtain a coolared through hole having a prescribe height even when executing ironing with use of volatile oil. CONSTITUTION:When the coolared through hole whose circumferential edge is enclosed by a prescribed height collar 6 is formed on a metal plate shaped body 1, boring of the small hole 2 smaller than the opened diameter of the collared through hole formed on this metal plate shaped body 1 and forming of a trapezoidal or columnar projecting part 3 having the minimum inside diameter larger than the diameter of the small hole 2 by the work of drawing the metal plate shaped body 1 on the circumferential edge part of the small hole 2 are carried out successively, or simultaneously, then, the shape of the small hole 2 formed on the upper end face of the projecting part 3 is adjusted to a prescribed shape, then, the projecting part 6 is subjected to ironing with a punch having an outside diameter equal to the opened hole diameter of the collared through hole and a die having an inside diameter equal to the outside diameter of the collar of the through hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing fins for heat exchangers used in heat exchangers such as automobile coolers and room coolers.

[0002]

2. Description of the Related Art Cooling fins used in a heat radiating portion of a heat exchanger such as an automobile cooler or a room cooler are
A plurality of through holes with collars having a predetermined height are provided on a metal plate such as a rectangular aluminum thin plate. In the heat radiating portion of the heat exchanger formed by such fins, a plurality of fins are polymerized by matching each of the colored through holes of each fin with each other, and copper or the like having a high thermal conductivity is spread over these through holes. A metal conduit is inserted and integrated. As a method for manufacturing such a heat exchanger fin,
The manufacturing method shown in FIG. 3 is proposed in Japanese Patent Publication No. 49-103808 and the like.

The manufacturing method shown in FIG. 3 includes the following steps. First, the metal plate 100 is perforated and burred to form a perforated hole 101 having a peripheral edge surrounded by a projecting piece 102 [step (a)], and then the perforated diameter of the perforated hole 101. Is enlarged and the projecting piece 102 is “ironed” while being extended, and an ironing process is performed to form the collar 104 having a predetermined height [steps (b) and (c)]. Such ironing is usually performed by "squeezing" the protruding piece 101 or the collar 103 with the outer wall surface of the punch and the inner wall surface of the die. In FIG. 3, the ironing process is performed in two stages, and the punch and die used in each stage have different diameters. The collar 104 having a predetermined height obtained in this manner has its tip end bent to form the collar 105 [(d) step].

According to the manufacturing method shown in FIG. 3 (hereinafter sometimes referred to as an ironing processing method), since the ironing processing is performed while expanding the diameter of the drilled hole, the periphery of the obtained collar is punched. There are no processing marks such as marks,
Moreover, the through hole with a collar having a predetermined height can be obtained even with a hard metal plate. By the way, in such an ironing processing method, it is necessary to perform it while using a processing oil, and normally, a nonvolatile oil is used as the processing oil. In this way, when the non-volatile oil is used during the ironing process, the non-volatile oil adheres to the obtained heat exchanger fins (hereinafter sometimes referred to as fins).
Conventionally, Freon (trademark) is used to perform cleaning to remove non-volatile oil adhering to the fins. However, due to the recent regulations on the use of freon gas for the purpose of global environment conservation, freon cannot be used as a solvent.
Therefore, the present inventors have tried to perform the ironing process using volatile oil in order to manufacture the fins without using Freon.

[0005]

As described above, the use of volatile oil during the ironing process
It is possible to eliminate the need for Freon cleaning of the resulting fins. However, when the volatile oil is used for the ironing process, the ironing rate decreases, which is the ratio of the metal plate that can be spread by ironing, as compared with the case of using the non-volatile oil. It was also found that the maximum height of the color of the was reduced. In particular, in recent years, it is often necessary to process a metal plate having a high hardness, and in combination with the use of volatile oil, the ironing rate is significantly reduced. Can be difficult to form. Then, the objective of this invention is providing the manufacturing method of the fin for heat exchangers which can obtain the through hole with a collar of predetermined height even if it performs an inning process using volatile oil.

[0006]

Means for Solving the Problems As a result of studies to achieve the above-mentioned object, the present inventors have made a small hole in advance and then formed a collar having a diameter-expanded small hole formed on the upper surface thereof. Even if a volatile oil is used, a predetermined height can be easily obtained by forming a truncated cone or a columnar convex part having a diameter substantially the same as the diameter of the attached through hole by drawing, and then subjecting the convex part to an ironing process. The present invention has been accomplished by finding that it is possible to manufacture a through hole with a collar. That is, according to the present invention, when forming a colored through hole in which the periphery of the through hole is surrounded by a collar of a predetermined height in a metal plate-shaped body, the colored through hole formed in the metal plate-shaped body is formed. Drilling a small hole having a diameter smaller than the diameter of the opening, and drawing a metal plate-like body at the peripheral portion of the small hole to form a trapezoidal or columnar convex portion having a minimum inner diameter larger than the diameter of the small hole. The formation is performed sequentially or simultaneously, and then the shape of the small hole formed on the upper end surface of the convex portion is adjusted to a predetermined shape, and then a punch having an outer diameter equal to the opening diameter of the through hole with a collar and the punch are formed. A heat exchanger fin manufacturing method is characterized in that a die having an inner diameter equal to the outer diameter of the collar of the through hole is used and the convex portion is subjected to ironing (ironing).

[0007]

In general, in the ironing process, the height of the protruding piece squeezed by the ironing process affects the collar height of the formed through hole with collar. On the other hand, in the conventional ironing method shown in FIG. 3, since the protruding piece is formed by burring, the height of the formed protruding piece is limited. Therefore, the height of the obtained colored through holes is directly influenced by the ironing ratio due to the hardness of the metal plate and / or the characteristics of the processing oil used. In this respect, according to the present invention, the height of the protruding piece to be subjected to the ironing process can be increased in advance by forming the trapezoidal or columnar convex portion having the small hole opened on the upper surface. Therefore, high hardness metal plate and / or
Alternatively, even if the ironing rate at the time of the ironing process is reduced by using the volatile oil, it is possible to easily form the colored through holes having a desired height.

[0008]

The present invention will be described in more detail with reference to the drawings. FIG. 1 is a process diagram for explaining the present invention, which includes the following steps. First, a circular small hole 2 is formed in the metal plate 1 [step (a) in FIG. 1]. This small hole 2
Is smaller than the diameter of the through hole with the collar to be formed. Next, the diameter of the small hole 2 is increased to form a truncated cone-shaped convex portion 3 [step (B) in FIG. 1]. The truncated cone-shaped convex portion 3 has a diameter that is substantially the same as the inner diameter of the through hole with a collar formed by the inner diameter of the bottom surface, and has an enlarged small diameter 2'opened on the upper surface. The small holes 2'opened on the upper surface of the convex portions 3 are small holes 2'because it is difficult to uniformly spread the metal plate 1 when forming the convex portions 3 while expanding the diameter of the small holes 2. Is likely to be distorted elliptical.

When the convex portion 3 having the small hole 2'having such a shape formed on the upper surface is subjected to an ironing process described later,
The resulting colored through-holes have uneven color height and / or
Or, cracks may occur in the collar. For this reason, in this embodiment, in order to adjust the shape of the small hole 2'to a circular shape, the circular hole 4 having a diameter of the major axis length of the small hole 2'is formed [Fig.
(C) step]. The height of the wall surface 5 of the convex portion 3 formed in this way can be made higher than that of the protruding piece 120 formed by the conventional burring process (step of FIG. 3A). In the present embodiment, the wall surface 5 of the formed convex portion 3 is subjected to an ironing process to form the collar 6 having a desired height [step (d) in FIG. 1]. Further, the collar 6 formed to have a desired height is bent at its tip to form the collar 7 [step (e) in FIG. 1].

Next, an apparatus used in the manufacturing method shown in FIG. 1 will be described with reference to FIG. Figure 1
Each mold shown in FIG. 2 can be used in each step shown in FIG. That is, the mold shown in FIG. 2A is used in the step of forming the small hole 2 in the metal plate body 1 in FIG. The mold is a piercing punch 10 and a piercing die 11.
Composed of and. Then, the step of FIG. 1B for forming the convex portion 3 while expanding the diameter of the small hole 2 formed by the die shown in FIG. 2A uses the die of FIG. 2B. ..
This die comprises a forming die 12 and a forming punch 14 which moves up and down in a direction perpendicular to the forming stripper 13. The metal plate 1 is sandwiched between a forming die 12 and a forming stripper 13, and a convex portion 3 is formed by a forming punch 14.
Is formed.

In the step (c) of FIG. 1 for shaping the small hole 2 ′ whose diameter has been expanded by the die of FIG. 2 (B),
The mold shown in FIG. 2 (C) is used. According to this mold, the metal plate 1 is sandwiched between the trimming die 15 and the trimming stopper 16, and the small hole 2 ′ is shaped by the trimming die punch 17 and the trimming punch 25 so that the circular hole 4 is formed. Is formed. Circular hole 4
The wall surface 5 of the protrusion 3 formed with is subjected to the ironing process of FIG. 1D using the mold shown in FIG. 2D. According to the mold of FIG. 2 (D), the metal plate 1 is sandwiched between the ironing die 21 and the ironing stripper 20, and the ironing punch 18 pushes up the knockout punch 19 inside the convex portion 3. Wall surface 5 of the convex portion 3
Squeeze and form the collar 6 on the periphery of the through hole.

After the collar 6 reaches a predetermined height, the collared through-hole is taken out from the ironing die 21 while lowering the ironing punch 18 by the knockout punch 19. The through hole with the collar taken out from the ironing die 21 is formed by bending the tip end portion of the collar 6 with the mold shown in FIG. 2 (E) to form the collar 7 [step of FIG. 1 (e)]. In such a die, the tip of the stepped reflare punch 24 is inserted into the through hole with the collar placed on the reflare die 22, and the tip of the collar is bent at the stepped portion of the reflare punch 24 to form the collar 7. It Tsuba 7
The metal plate-shaped body 1 is pressed by the ejector pins 23, and the through holes with collars formed with are removed from the mold by the lifting of the flare punch 24.

In the embodiment described above, the step of FIG. 1A for forming the small hole 2 in the metal plate 1 and the convex portion while expanding the diameter of the small hole 2 formed. The step of forming the small holes 3 and the step 3 of FIG.
However, the formation of the small holes 2 and the formation of the convex portions 3 may be performed at the same time. Further, in the present embodiment, the collar 6 having a desired height can be formed by one step of the ironing process, and it is not necessary to use the two steps of the ironing process unlike the conventional ironing process shown in FIG. Needless to say, the ironing process may be performed in two steps, if necessary. Further, the smaller the diameter of the small hole 2 formed in the step of FIG. 1A, the smaller the convex portion 3 formed.
Although the height of the wall surface 5 of the small hole 2 can be increased, the smaller the diameter of the small hole 2 is, the greater the distortion of the shape of the expanded small diameter 2'when forming the convex portion 3 becomes. The wall surface 5 of 3 may crack. Small holes 2 where such cracks occur
Since the minimum diameter of 1 depends on the characteristics such as the hardness of the metal plate 1 used, it is preferable to experimentally determine in advance the minimum diameter of the small hole 2 in which the convex portion 3 can be formed without problems.

[0014]

According to the present invention, a highly hard metal plate and / or a volatile oil is used during the ironing process, and even if the ironing rate is remarkably reduced, the colored transparent member with a predetermined height is used. Holes can be formed. Therefore, it is possible to sufficiently comply with the freon gas regulation and the like.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining a process of the present invention.

FIG. 2 is an explanatory diagram for explaining a mold used in the process shown in FIG.

FIG. 3 is an explanatory diagram illustrating a conventional ironing processing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal plate body 2 Small hole 2'Expanded small hole 3 Conical convex part 4 Circular hole 5 Wall surface of convex part 6 Color 7 Collar

Claims (1)

[Claims] 1. When forming a colored through hole in which a peripheral edge of the through hole is surrounded by a collar of a predetermined height in a metal plate-shaped body, an opening of the colored through hole formed in the metal plate-shaped body is formed. Forming a trapezoidal or columnar convex part having a minimum inner diameter larger than the diameter of the small hole by drilling a small hole having a diameter smaller than the hole diameter and drawing the metal plate-like body at the peripheral portion of the small hole. And then sequentially or simultaneously, and after adjusting the shape of the small hole formed on the upper end surface of the convex portion to a predetermined shape, a punch having an outer diameter equal to the opening diameter of the through hole with a collar and the transparent member are formed. A method for producing a fin for a heat exchanger, characterized in that a die having an inner diameter equal to an outer diameter of a collar of a hole is used to perform an ironing process on the convex portion.