JPS63201495A - Heat exchanger - Google Patents

Abstract

PURPOSE:To improve the heat exchanging performance of fins, by a method wherein louvers are formed on the root of a fin, which is near to a tube, while corrugated recessed and projected surfaces are formed on the central flat part of the fin. CONSTITUTION:Louvers 5, 5, formed on a fin 2, increase a heat transfer rate between air and the fin as well as a ventilating resistance, therefore, heat exchanging efficiency between air and the fin is increased. Especially, the louvers 5, 5 are formed on the root of the fin 2, which is near a flat tube 1, therefore, the louvers 5, 5, provided at a part whereat the temperature of the air is high, develop heat exchanging effect between the air sufficiently, whereby the heat exchanging performance is increased. Further, the concave and convex surfaces 6 are formed on a flat part between the left and right louvers 5, 5; therefore, the heat transfer rate of the flat part is increased, whereby the heat transfer efficiency of the whole of the fin 2 may be increased. The separation or the turbulent flow of cooling air, flowing along the flat part, is promoted by the concave and convex surfaces 6 and the resistance of flow is increased. Concave and convex surfaces guide the cooling air toward the louvers 5, 5; therefore, the flow rate of the air, flowing through the louvers 5, 5 having a high heat dissipating performance, is increased, whereby the heat exchanging efficiency of the heat exchanger may be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat exchanger suitable for automobile radiators and automobile air conditioning systems.

[Conventional technology]

Conventionally, heat exchangers used as automobile radiators or automobile air-conditioning systems are made of, for example, a flat tube through which refrigerant or hot water passes, and corrugated fins or plates, as shown in Japanese Utility Model Application Publication No. 59-97378. It has a laminated structure with fins arranged alternately, and these fins are brazed or soldered to the flat tube.

In the conventional heat exchanger described above, in order to improve heat exchange performance with air, louvers are cut and raised on the fins to improve the leading edge effect of the temperature boundary layer. In other words, when the heat of the flat tube is conducted to the fins, heat is exchanged with the air flowing over the surface of the fins.
When a louver portion is formed on the fin, the efficiency of heat transfer with the air increases and good heat exchange is performed.

[Problem that the invention seeks to solve]

However, the conventional louver part is formed in the central flat part between the flat tubes of the fin, and the area between this louver part and the flat tube joint at the fin side end, that is, the root part of the fin, has a flat shape. Ta.

With such a structure, the air flowing into the fins avoids the louver part with high resistance and flows at a high speed through the flat parts with low resistance formed on both sides of the louver part, resulting in a decrease in heat transfer coefficient. Since heat is exchanged in a small flat area, not only is the efficiency not good, but the amount of air passing through the louver is relatively small, and the heat exchange function of the louver is not fully utilized.

The present invention aims to provide a heat exchanger that can further improve heat exchange performance with fins.

[Means for solving problems]

The present invention is characterized in that a louver is formed in the root portion of the fin near the tube, and a wavy uneven surface is formed in the central flat portion of the fin.

[Effect]

According to the present invention, a louver is formed at the base of the fin where the temperature is high due to its proximity to the tube, increasing heat transfer efficiency and increasing the rigidity of the fin.In addition, a wavy uneven surface is formed on the flat central part of the fin. Therefore, the heat transfer efficiency increases in this part as well, and this wavy uneven surface increases air resistance and increases the amount of air flowing into the louver part.
The heat dissipation function of the louver can be fully demonstrated.

〔Example〕

Hereinafter, regarding the present invention, the first embodiment shown in FIGS. 1 to 6 will be explained.
This will be explained based on an example.

FIG. 4 shows the entire heat exchanger, and numeral 1 denotes flat tubes made of aluminum or copper alloy, which are arranged in a meandering pattern. Corrugated fins 2 made of aluminum or copper alloy are interposed between the meandering flat tubes 1, and the bent portions of the corrugated fins 2 are joined to the side surfaces of the flat tubes 1 by soldering or brazing. ing.

One end of the flat tube 1 is connected to an inflow pipe 3, and the other end is connected to an outflow pipe 4.

As shown in FIG. 1, the corrugated fin 2 has louver portions 5, 5 formed at the root portion close to the flat tube 1, that is, at the bent portion. These louver parts 5, 5 are formed by integrally forming a large number of louver pieces 5a..., 5b... at the root part of the corrugated fin 2 along the air flow direction, and each louver piece 5a... ..., 5b
. . . are formed alternately above and below the figure, as shown in cross section in FIG. 2.

Note that the air flows in the direction of arrow F in FIG.

In this embodiment, each of these louver pieces 5a..., 5b...
... are brazed or soldered to the side wall of the flat tube 1. In addition, the louver piece 5a
... or 5b... the interval is 1 of the pitch of fin 2
/4 is good.

An uneven surface 6 is formed in the central flat portion of the corrugated fin 2 between the louver portions 5°5. This uneven surface 6 is integrally formed by pressing a central flat part, and has triangular peaks 6a and valleys 6b with an inclination angle of 10 to 20 degrees, for example, as shown in FIG. ... are formed alternately along the air flow direction to form a waveform.

Note that the louver portions 5 and 6 and the uneven surface 6 of the central flat portion
can be integrally molded at the same time.

That is, in the past, corrugated fins were obtained by forming a corrugated fin by passing a fin-constituting plate 22 between a pair of gear-shaped forming tools 20 and 21, as shown in FIG. In this case, the fin-constituting plate material 22 was passed between gear-shaped forming tools 20 and 21 to give it a meandering shape.

In order to form the louver portions 5, 6 and the uneven surface 6 as in this embodiment, a sixth
Cut and raised teeth 28, 23 and an uneven molded surface 24 as shown in the figure are formed in advance. The cut and raised teeth 23 and 28 are provided at the end of the tooth surface, and a concave and convex molded surface 24 is formed between the cut and raised teeth 28 and 23 on the tooth surface. In this way, by passing the fin-constituting plate material 22 between the pair of gear-shaped forming tools 20 and 21, the fin forming plate material 22 is formed into a wave shape to give a wave shape, and at the same time, the louver 5 and the uneven surface 6 are formed. Can be molded.

According to the embodiment having such a configuration, the refrigerant and hot water passing through the refrigerant passage 7 in the flat tube 1 exchange heat with the fins 2 through the wall of the flat tube 1.

The fins 2 exchange heat with the air flowing over their surfaces. In this case, the louver portions 5.5 formed on the fins 2 increase the heat transfer coefficient with the air and the ventilation resistance, thereby increasing the efficiency of heat exchange with the air. In particular, since the louver parts 5, 5 are formed at the root part of the fin 2 close to the flat tube 1, this root part is a part where the temperature is high due to heat conduction from the flat tube 1, and therefore it is installed in a high temperature part. The louvered portion 5.5 exhibits a sufficient heat exchange effect with the air, increasing heat exchange performance.

Further, since the louver portions 5, 5 are formed at the root portions of the fins 2 joined to the flat tube 1, the rigidity of the fins 2 is increased.

Moreover, an uneven surface 6 is formed on the flat part between the left and right louver parts 5, 5.
Since the heat transfer coefficient of the flat portion is increased compared to the case where the uneven surface 6 is not provided, the heat transfer efficiency of the entire fin 2 is increased, thereby increasing the heat exchange efficiency. In addition, the uneven surface 6 promotes separation and turbulence of the cooling air flowing along the flat portion, so the resistance to the flow increases, and therefore the uneven surface 6 directs the cooling air toward the louver portions 5, 5. Therefore, the amount of air flowing through the louver parts 5, 5 having high heat dissipation performance increases, and the heat exchange efficiency is further improved.

Further, the uneven surface 6 formed on the flat portion increases the mechanical strength of the flat portion.

In the first embodiment, the louver portion 5 is formed of a large number of louver pieces 5a, 5b, etc., which are alternately arranged vertically in the figure.
As in the second embodiment shown in FIG. 7, the shape may be such that a large number of louver pieces 30 are cut and raised at an angle.

Further, in the first embodiment, the uneven surface 6 of the flat portion is formed of triangular peaks 6a and valleys 6b, but the present invention is as shown in FIG. As in the third embodiment, the uneven surface has round peaks 40a... and valleys 4.
0b... may be formed into a waveform.

Further, the uneven surface 6 formed on the flat part between the louver parts 5, 5 is not limited to one row, but may be provided in a plurality of rows.

Furthermore, the fins 2 are not limited to corrugated fins, but may also be plate fins, and the tube 1 is not limited to being flat, but may also be an elliptical or round tube.

〔Effect of the invention〕

As explained above, according to the present invention, since the louver is formed at the base of the fin, which is close to the tube and has a high temperature, the heat transfer efficiency is increased and the rigidity of the fin is increased. Since the uneven surface is formed, heat transfer efficiency is increased in this area as well, and this wavy uneven surface increases air resistance and increases the amount of air flowing into the louver, so the heat dissipation function of the louver can be fully demonstrated. This has the effect of improving heat exchange capacity compared to conventional methods.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, FIG. 1 is an enlarged perspective view of a part of FIG. 4, and FIGS. 2 and 3 are parts of FIG. 1, respectively. 4 is a front view of the entire heat exchanger, 5 and 6 are diagrams each illustrating a corrugated fin manufacturing apparatus, and 7 is a cross-sectional view taken along lines ■-■ and ■-■. 8 is a sectional view of a portion corresponding to FIG. 2 showing a second embodiment of the present invention, and FIG. 8 is a sectional view of a portion corresponding to FIG. 3 showing a third embodiment of the present invention. ■...Flat tube, 2...Corrugated fin, 5
゜5...-louver part, 6... uneven surface. Applicant's agent Patent attorney Takehiko Suzue b. Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] In a heat exchanger in which a core portion is formed by joining corrugated fins or plate fins to a tube through which liquid flows, a louver is formed at the root portion of the fin near the tube, and a wavy shape is formed in the central flat portion of the fin. A heat exchanger characterized by forming an uneven surface.