JPH08178571A - Heat exchanger - Google Patents

Abstract

PURPOSE: To improve the heat transfer rate of corrugated fins, to obtain the heat radiating area and to improve the radiating performance. CONSTITUTION: Fine yarnlike circular-arclike wires 22 are formed on the flat surfaces 21 of corrugated fins 2, the wires 22 are alternately reversely bent to be molded, and gradually varied in its bending width and height in a fluid flowing direction C. Thus, a temperature boundary layer formed on the surface of the wires 22 is not continuously formed as adjacent one, but separated to be extremely thin. As a result, even in the case of the fin 2, a high heat transfer rate near a pin fin or a net fin can be realized. Further, since the wire groups can be formed substantially over the entire area of the surfaces 21 of the fins 2, the radiating area can be obtained in the same degree of the area as a conventional louver fin, thereby remarkably improving the radiating performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger whose fin shape is improved to improve its heat transfer coefficient, and is suitable for use in, for example, a radiator for an automobile.

[0002]

2. Description of the Related Art Conventionally, as means for improving the heat transfer coefficient on the air side in a heat exchanger such as an automobile radiator, as shown in FIG. 6, a flat tube 1 and a corrugated fin 2 are used.
Are joined together, and a large number of louvers 2a are obliquely cut and raised at a predetermined angle on the flat surface 21 of the corrugated fin 2 to form a so-called louver fin, or the flat surface 21 of the corrugated fin 2 as shown in FIG. A typical structure is a so-called slit fin in which a large number of gate-shaped louvers 2b having a plane parallel to the flat surface 21 are cut and raised.

[0003]

The above louver fins and slit fins have undergone various researches and improvements and have been widely commercialized. However, improvement in performance due to improvements in louver shape, dimensional specifications, etc. has almost reached the limit. Therefore, it is difficult to further improve the performance. Therefore, in recent years, a heat exchanger using a pin fin 3 as shown in FIG. 8 and a net fin 4 formed in a stitch shape as shown in FIG. 9 has been studied. In these pin fins 3 and net fins 4, since the temperature boundary layer is finely divided and does not develop into a thick layer due to the use of thin wires, there is an advantage that the heat transfer coefficient is significantly improved as compared with the above louver fins and slit fins. .

On the other hand, however, since the heat radiation area is reduced, when compared with the same heat exchange volume, there is a problem that the heat radiation performance is lower than that using the louver fins or slit fins. . The present invention has been made in view of the above points, while ensuring a high heat transfer rate comparable to pin fins and net fins, the expansion of the heat dissipation area,
It is an object of the present invention to provide a heat exchanger that can improve heat dissipation performance.

[0005]

In order to achieve the above object, the present invention employs the following technical means. In the invention according to claim 1, a flat tube (1) having a flat cross section,
A heat exchanger having a corrugated fin (2) bent into a corrugated shape and joined to a flat surface of the flat tube (1), wherein the flat surface (21) of the corrugated fin (2) has both front and back surfaces. A large number of thin wires (22) alternately bent into an arc shape are formed on the flat surface, and the bending width (W) and bending height (H) of the large number of arc thin wires (22) are the flat surface. (21) Fluid flow direction (C)
It is characterized by a heat exchanger configured to gradually change from one end side to the other end side.

According to a second aspect of the present invention, in the heat exchanger according to the first aspect, the interval (d) between the arcuate thin wires (22) is substantially equal to the plate thickness (t) of the corrugated fins (2). The feature is that they are set to the same size. According to a third aspect of the present invention, in the heat exchanger according to the first or second aspect, a bending width (W) from one end side of the flat surface (21) in the fluid flow direction (C) to the other end side thereof and A group of arc-shaped fine wires (22) composed of a large number of arc-shaped fine wires (22) configured so that the bending height (H) gradually changes is the flat surface (2).
A plurality of them are formed in the fluid flow direction (C) of 1).

According to a fourth aspect of the present invention, in the heat exchanger according to any one of the first to third aspects, the flat surface (21) of the corrugated fin (2) is equidistant and the flat surface is formed. A large number of slits (S) are formed with a width dimension that gradually changes from one end side to the other end side of the surface (21) in the fluid flow direction (C), and a pressing force is applied in the width direction of the slits (S). It is characterized in that the arc-shaped thin wire (22) is formed by acting.

The reference numerals in parentheses of the above-mentioned means indicate the correspondence with the concrete means described in the embodiments described later.

[0009]

According to the inventions of claims 1 to 4,
Since the above-mentioned technical means is provided, the heat dissipation portion of the corrugated fin can be formed by a thin thread-shaped arc-shaped thin wire, and this arc-shaped thin wire is bent in the opposite direction alternately with the adjacent arc-shaped thin wires. Since the bending width and the bending height are gradually changed in the fluid flow direction, the temperature boundary layer formed on the surface of each arc-shaped thin wire may be formed continuously with the adjacent one. Instead, it becomes a very thin one that is divided into parts.

As a result, in the heat dissipation portion of the corrugated fin according to the present invention, a high heat transfer coefficient similar to that of a pin fin or a net fin can be realized. Moreover, since the arcuate thin wire group can be formed over almost the entire area of the flat surface of the corrugated fin, the heat radiation area can be as large as that of the conventional louver fin, so that the heat radiation performance of the heat exchanger can be dramatically improved. Can be improved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a fin shape according to the present invention, which is basically constituted by a corrugated fin 2 which is bent and formed in a conventional corrugated shape as a base. A large number of thin wires 22 which are alternately bent and formed in an arc shape are formed on both front and back sides.

In FIG. 1, A shows a portion of the large number of arc-shaped thin wires 22 which is bent and formed on the front side (upper side) of the flat surface 21, and B is bent and formed on the back side (lower side) of the flat surface 21. Is shown, and the circular thin wires 22 and B of this A portion are shown.
The arcuate thin wires 22 of the part are formed alternately. Reference numeral 23 is a bent portion of the corrugated fin 2. The bending width W (see FIG. 2) and the bending height H (see FIG. 3) of the large number of arc-shaped thin wires 22 are from one end side to the other end side in the cooling air (fluid) flow direction C of the flat surface 21. It is configured to gradually decrease toward. In this example, as shown in FIG. 3A, the maximum bending height H of the arc-shaped thin wires 22 in one arc-shaped thin wire group consisting of a large number of arc-shaped thin wires 22.
Is approximately 1/2 of the fin pitch Fp of the corrugated fins 2.
Is set to

The corrugated fin 2 is formed from a metal such as aluminum or brass having excellent heat conductivity, corrosion resistance, brazing property (solderability), etc., and its plate thickness t is 0.1. The thin plates are about 0.15 mm, and the distance d between the arc-shaped fine wires 22 formed at equal intervals (the distance between the slits S for forming the arc-shaped fine wires described later) is approximately the same as the plate thickness t of the corrugated fin 2. Is set to.

FIG. 3B shows, as an example of the dimensions, a case where both t and d are set to 0.1 mm. As can be understood from this specific dimension example, the arc-shaped fine line 22 is It is formed into a fine thread. Further, the bending height H of each arcuate thin wire 22 is gradually decreased by the plate thickness t, as shown in FIG.

The flat surface 21 of the corrugated fin 2
On the upper side, a plurality of arc-shaped fine wire groups constituted by the large number of arc-shaped fine wires 22 are formed. That is, one arc-shaped thin wire is formed by a large number of arc-shaped thin wires 22 whose bending width W and bending height H gradually decrease from one end side to the other end side of the flat surface 21 of the corrugated fin 2 in the air flow direction C. A group is formed, and a plurality of (five in FIG. 1) arc-shaped fine wire groups are formed in the air flow direction of the flat surface 21.

In FIG. 3 (a), the above 1
Since the number of the arc-shaped thin wires 22 in one arc-shaped thin wire group is 20, the length L of one thin wire group is 20 × 0.1 mm.
= 2 mm. When eight thin wire groups are formed, the total length L ₀ is 8 × 2 mm = 20 mm. FIG. 4 shows a heat exchange section in which a corrugated fin 2 having a plurality of arc-shaped fine wire groups described above and a flat tube 1 having a flat cross-sectional shape are joined, and a large number of corrugated fins 2 and flat tubes 1 are alternately arranged. After the assembly, the bent portion 23 of the corrugated fin 2 is joined to the flat surface of the flat tube 1.

The flat tube 1 is also made of the same metal as the corrugated fin 2, and the both 1 and 2 are integrally joined by brazing or soldering. In an automobile radiator, both ends of the flat tube 1 communicate with upper and lower tanks having an engine cooling water inlet pipe and an engine cooling water outlet pipe, respectively.
Heat is exchanged between the cooling air blown in the direction of arrow C in FIG. 4 and the engine cooling water to cool the engine cooling water.

Next, the manufacturing method of the heat exchanger of the present invention will be described. First, in forming the corrugated fin 2, as shown in FIG. 5 (a), the above-mentioned thin metal plate having a plate thickness t = 0.1 mm is used. Then, a predetermined number of slits S are formed at substantially the same intervals as the plate thickness t. At this time, the width of the predetermined number of slits S is gradually reduced (see a, b, c in FIG. 5A) so that the bending width W of the arc-shaped fine wire 22 described above can be obtained.

Then, a slit group consisting of the predetermined number of slits S is repeatedly formed by the required number of the above-mentioned arcuate thin wire group. When making the slit S,
At the same time, the slits S are alternately arranged in opposite directions (see FIG.
(A) Raise it in an arcuate shape in the upper direction A and direction B. Further, at the same time when the slit S is cut, the corrugated fin 2 is formed into a corrugated shape.

The processing of the slit S and the corrugation of the corrugated fin 2 can be simultaneously performed by using a gear-shaped molding blade. Next, the corrugated fin 2 in which the slit S is processed and the flat tube 1
And are assembled alternately, and then, for this assembly,
As shown by the arrow B in (b), a pressing force is applied to the corrugated fin 2 through the flat tube 1 from the direction of compressing the width of the slit S.

Due to this pressing force, each slit S portion expands in the vertical direction (A and B directions) in FIG. 5B, and a group of arc-shaped fine lines having a predetermined bending width W and bending height H. Can be formed, resulting in the fin shape shown in FIG. Next, the core plate other than the heat exchange section (flat tube 1, corrugated fins 2), tank, inlet / outlet pipe, etc. are assembled, and the assembled state is maintained by a jig or the like and carried into the brazing furnace. Then, each part of the assembly is joined. With the above, the heat exchanger can be completed.

According to the above heat exchanger structure, the heat dissipation portion of the corrugated fins 2 is formed by the arc-shaped thin wires 22 formed in the shape of extremely fine threads, and the arc-shaped thin wires 22 are adjacent to each other. Formed on the surface of each arc-shaped thin wire 22 because it is bent and formed alternately with the thin wire 22 in the opposite direction, and its bending width W and bending height H gradually decrease in the air flow direction as the cooling medium. The temperature boundary layer is not formed continuously with the adjacent one, but is separated and extremely thin.

As a result, in the heat dissipation portion of the corrugated fin 2 according to the present invention, it is possible to realize a high heat transfer coefficient similar to that of a pin fin or a net fin. Moreover, since the arcuate thin wire group can be formed over almost the entire area of the flat surface 21 of the corrugated fin 2, the heat radiation area can be as large as that of the conventional louver fins, so that the heat radiation performance of the heat exchanger can be improved. Can be improved.

In the embodiment described above, the bending width W and the bending height H of the large number of arc-shaped fine wires 22 are gradually reduced from one end side of the flat surface 21 in the fluid flow direction C to the other end side. However, on the contrary, a large number of arc-shaped fine wires 22 having bending widths W and bending heights H from one end side to the other end side of the flat surface 21 in the fluid flow direction C are formed. Even if it is configured so as to gradually increase, the same operational effect can be exhibited.

Further, it goes without saying that the heat exchanger of the present invention is not limited to radiators for automobiles but can be widely applied to various purposes.

[Brief description of drawings]

FIG. 1 is a partial perspective view showing an embodiment of a corrugated fin according to the present invention.

FIG. 2 is an enlarged front view of a main part of the corrugated fin of FIG.

3A is a cross-sectional view of a main part of the corrugated fin of FIG. 1, and FIG. 3B is an enlarged view of a Y portion of FIG.

FIG. 4 is a partial perspective view of a heat exchange section in which a corrugated fin and a flat tube according to the present invention are assembled.

FIG. 5 is an explanatory view illustrating a method for forming a corrugated fin according to the present invention.

FIG. 6 is a partial perspective view of a heat exchange section showing a conventional louver fin shape.

FIG. 7 is a partial perspective view of a heat exchanging portion showing a conventional slit fin shape.

FIG. 8 is a partial perspective view of a conventional heat exchange section showing a pin fin shape.

FIG. 9 is a partial perspective view of a heat exchange section showing a conventional net fin shape.

[Explanation of symbols]

1 ... Flat tube, 2 ... Corrugated fin, 21 ...
… Flat surface, 22 …… Arcuate thin wire, W …… Bending width, H ……
Bending height.

Claims (4)

[Claims] 1. A heat exchanger having a flat tube having a flat cross section and a corrugated fin bent into a corrugated shape and joined to a flat surface of the flat tube, wherein the flat surface of the corrugated fin is A large number of thin wires that are alternately bent and formed in an arc shape are formed on both front and back sides. The number of arc-shaped thin wires has a bending width and a bending height from one end to the other end in the fluid flow direction of the flat surface. A heat exchanger characterized in that it is configured to gradually change toward the side. 2. The heat exchanger according to claim 1, wherein an interval between the arc-shaped thin wires is set to be substantially the same as a plate thickness of the corrugated fins. 3. An arc-shaped thin wire group composed of a large number of arc-shaped thin wires configured such that the bending width and the bending height gradually change from one end side to the other end side of the flat surface in the fluid flow direction, The heat exchanger according to claim 1, wherein a plurality of heat exchangers are formed in the fluid flow direction of the flat surface. 4. A plurality of slits are formed on the flat surface of the corrugated fin at equal intervals and with a width dimension that gradually changes from one end side to the other end side of the flat surface in the fluid flow direction. The heat exchanger according to any one of claims 1 to 3, wherein the circular thin wire is formed by applying a pressing force in the width direction of the slit.