JP4697686B2 - Heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanger used as an automobile radiator or the like.

  2. Description of the Related Art An automobile radiator is known that includes a radiator core that is formed by alternately stacking tubes and fins having cooling water passages therein, and the fins are corrugated fins. The cooling water warmed by the engine is cooled by natural ventilation flowing through the corrugated fin gap and / or forced ventilation by a fan disposed behind the radiator core while passing through the tube in the radiator.

  By the way, with improvement in engine performance and the like, higher heat dissipation performance is also required for the radiator, and therefore, a corrugated fin with a large number of louvers formed on its surface is adopted, resulting in an increase in heat dissipation area Improvement of heat exchange efficiency is aimed at (for example, refer to the following patent documents 1).

However, if a large number of louvers are formed on the surface of the corrugated fin, the air gap becomes narrow and the flow resistance of the air flowing therethrough increases, so even if the performance of the fan used is improved, the heat dissipation performance There was a limit to improvement.
Japanese Patent Laid-Open No. 2003-83692

  An object of the present invention is to provide a heat exchanger that can obtain extremely excellent heat dissipation performance when used as an automobile radiator or the like.

  The heat exchanger according to the present invention includes a core formed by alternately stacking tubes and fins having fluid passages therein, and the fins have spiral ribs on the inner surface. It is characterized by being formed by a plurality of metal tubes arranged so as to intersect the tubes.

  According to the heat exchanger of the present invention, when this is used, for example, in a radiator for an automobile, air passes through the inside of the metal tube constituting the fin, so that the flow resistance is small and the spiral rib on the inner surface of the metal tube As a result, the air becomes a swirling flow and heat dissipation is promoted, so that the heat dissipation performance is greatly improved.

  In the heat exchanger according to the present invention, preferably, the rib on the inner surface of the metal tube is formed on the back side of the groove by forming a spiral groove on the outer surface of the metal tube.

If the spiral rib on the inner surface of the metal tube is formed as described above, the manufacturing is easy and the cost can be reduced.
As a method of manufacturing a ribbed metal tube, a metal tube having a circular cross section is sent in the length direction while rotating around an axis by a three-point roller, at least one of which is a grooved roller, and is applied to the outer surface of the metal tube. A preferable embodiment includes a step of forming a spiral rib on the inner surface by forming a spiral groove.
However, the manufacturing method of the metal pipe with spiral ribs is not limited to the above, and, for example, an extruded pipe formed using a mold in which one or more ribs extending in the length direction are formed on the inner surface. Alternatively, the drawn tube can be manufactured by a method including a step of twisting around the axis at the time of molding or in a later step.

  The material of the ribbed metal tube is not particularly limited, but preferably aluminum (including an aluminum alloy) that is lightweight and easy to process is used.

The metal tubes are usually arranged in a row between adjacent tubes, or in addition, between the tubes and the side plates located at both ends, and the outer surfaces of the adjacent tubes or between the outer surface and the side plate. Joined to the outer surface by brazing or the like. In addition, the metal tubes may be arranged in two or more rows at each of the above positions. Further, the metal pipes may be arranged in a staggered manner at the respective positions.
The required number of metal tubes are arranged at each of the above-mentioned positions so as to cover the entire length of the tube. In addition, although a metal tube is normally arranged so that it may orthogonally cross with a tube, depending on the flow direction of air, it may be arranged so that it may cross | intersect diagonally with respect to a tube.
Adjacent metal pipes arranged at the respective positions are preferably brought into contact with each other and joined by brazing or the like. Thereby, the intensity | strength as the whole core improves, and joining operations, such as brazing, can be performed easily. However, it is also possible to arrange so that a slight gap is generated between adjacent metal tubes.
It is sufficient that at least one spiral rib is formed on the inner surface of the metal tube, but a plurality of ribs may be formed, thereby increasing the heat radiation area.
Normally, one type of metal tube having the same outer diameter is used for the fin, but the fin may be formed by appropriately arranging two or more types of metal tubes having different outer diameters in combination. .

  The heat exchanger of the present invention is particularly preferably used as a radiator for automobiles, but it can of course be used for other purposes.

  An embodiment of the present invention will be described with reference to FIGS. In this embodiment, the present invention is applied to an automobile radiator.

  FIG. 1 shows the entire radiator. The radiator (1) includes a radiator core (2) formed by alternately stacking tubes (3) and fins (4) in the left-right direction. The upper and lower ends of each tube (3) are connected to the upper tank (5A) and the lower tank (5B), respectively. Side plates (6) are arranged at predetermined intervals on the outside of the tubes (3) located at the left and right ends, and fins (4) are also provided between the tubes (3) and the side plates (6). Is intervened. Although not shown, a fan is attached to the rear surface of the radiator core (2).

  As shown in FIG. 2, the tube (3) has a flat hollow shape having a plurality of cooling water passages (31) therein, and is formed from an aluminum hollow extruded shape.

As shown in FIGS. 1 to 4, the fin (4) includes a plurality of aluminum tubes (40) having a spiral rib (41) on the inner surface and arranged so as to be orthogonal to the tube (3).
The rib (41) on the inner surface of the aluminum tube (40) is formed on the back side of the groove (42) by forming a spiral groove (42) on the outer surface of the aluminum tube (40). It extends over the entire length of (40).
The length of the aluminum tube (40) is substantially equal to the width of the tube (3) in the front-rear direction (see FIGS. 2 and 3). The outer diameter of the aluminum tube (40) is substantially equal to the distance between the adjacent tubes (3), and is about twice that of the thickness of the tube (3) (see FIG. 2). .
Specifically, for example, aluminum having an outer diameter of about 2 to 12 mm, a thickness of about 0.1 to 0.8 mm, and a spiral rib (41) having a height of about 5 to 30% of the outer diameter on the inner surface. A tube (40) is used as the fin (4). The length of the aluminum pipe (40) is, for example, about 110 mm in the case of a truck and about 40 mm in the case of a passenger car.
The aluminum pipes (40) vertically adjacent to each other are brought into contact with each other and joined by brazing (see FIG. 3). Each aluminum tube (40) is brought into contact with the surface of two adjacent tubes (3) or the surfaces of the tubes (3) and side plates (6) located at the ends and joined by brazing. Has been.

  The upper tank (5A) and the lower tank (5B) each have an aluminum tank body (51) and an aluminum core joined to the tank body (51) so as to close the opening thereof and having a tube insertion hole (not shown). It consists of a plate (52). An upper hose (not shown) for introducing cooling water is connected to the upper tank (5A), and a lower hose (not shown) for discharging cooling water is connected to the lower tank (5B). A radiator cap (53) is provided on the top of the upper tank (5A).

  The side plate (6) is also made of aluminum, and is formed into a U-shaped cross section by bending both edge portions outward in the left-right direction.

FIG. 5 shows an example of a method for manufacturing an aluminum pipe (40) with ribs (41) constituting the fin (4).
In this method, an aluminum base tube (40A) having a circular cross section is sent in the length direction while rotating around an axis by a three-point roller (71, 71, 71X), one of which is a grooved roller (71X). This includes a step of forming a spiral rib (41) on the inner surface of the base tube (40A) by forming a spiral groove (42) on the outer surface.
The aluminum tube (40) with the rib (41) thus obtained is cut by a predetermined length and used as the fin (4).
According to said method, manufacture of the aluminum pipe (40) with a rib (41) is easy, mass production is possible, and cost can be held down.

  The radiator (1) includes, for example, a tube (3), a fin (4) (= a metal pipe (40) with a rib (41)), a tank body (51), a core plate (52), and a side plate (6). Produced by forming a brazing filler metal layer in advance on at least one of the abutting surfaces of component parts, etc., and brazing them in a furnace while restraining these component parts with a jig Has been.

In the radiator (1), the cooling water warmed by the engine is introduced into the upper tank (5A), and flows downward through the cooling water passage (31) of each tube (3) from there. After 5B), it is returned to the engine.
Here, while the cooling water flows through the cooling water passage of the tube (3), natural air and / or forced ventilation by a fan flowing through the gaps of the fins (4), that is, the inside of each metal pipe (40). To be cooled. At this time, the flow rate of air per unit time is extremely large because the flow resistance is small inside the metal tube (40). In addition, since the spiral rib (41) is formed on the inner surface of the metal tube (40), the air flowing inside the metal tube (40) becomes a swirling flow due to the presence of the rib (41), thereby the tube. (3) Heat dissipation from the cooling water flowing inside is promoted.
Therefore, according to said radiator (1), compared with the conventional radiator provided with the corrugated fin, heat dissipation performance can improve drastically, and it can contribute to the improvement of the performance of a motor vehicle itself by extension.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention, and is an overall front view of an automotive radiator. It is a horizontal sectional view which expands and shows a part of radiator core. FIG. 3 is a vertical sectional view of the radiator core taken along line III-III in FIG. 2. It is a perspective view of the aluminum tube with a rib which comprises a fin. It shows the manufacturing method of the aluminum tube with a rib, Comprising: (a) is a side view, (b) is an expanded vertical sectional view which follows the bb line of (a).

Explanation of symbols

(1): Radiator (heat exchanger)
(2): Radiator core (core)
(3): Tube (31): Cooling water passage (fluid passage)
(4): Fin (40): Aluminum tube (metal tube)
(41): Spiral rib (42): Spiral groove

Claims (3)

In a heat exchanger having a core formed by alternately stacking tubes and fins having fluid passages therein,
The fin is formed by a plurality of metal tubes having spiral ribs on the inner surface and arranged to intersect the tube, and adjacent metal tubes are brought into contact with each other and joined. Heat exchanger. The metal tube is sent in the length direction while rotating around the axis by a three-point roller, at least one of which is a grooved roller, to form a spiral groove on the outer surface of the metal tube. The heat exchanger according to claim 1 , wherein a spiral rib is formed on the inner surface . In an automobile radiator having a radiator core formed by alternately stacking tubes and fins having cooling water passages therein,
The fin has a spiral rib on the inner surface and is formed by a plurality of aluminum tubes arranged so as to intersect the tube. The aluminum tube has an outer diameter of 2 to 12 mm and a thickness of 0.1 to 0.8 mm. A radiator for an automobile, wherein the height of the rib is 5 to 30% of the outer diameter, and adjacent aluminum tubes are brought into contact with each other and joined.

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