JPH09280754A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger which is excellent in mass productivity and reliability, and provided with measures for preventing the frost. SOLUTION: A plurality of flat tubes 10 are arranged in parallel with the prescribed intervals in the thickness direction. Corrugated fins 14 are interposed between the flat tubes 10, and a pair of hollow headers are arranged at each end of the tubes 10 in a continuously connected condition. A plurality of reinforcement ribs 14b are formed on a windward side part of the corrugated fins 14, and a plurality of louvers 14a are formed on a leeward side part thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger, and more particularly to a heat pump type outdoor heat exchanger for a room air conditioner and a heat exchanger used as a heat exchanger for a car air conditioner of the same type.

[0002]

2. Description of the Related Art Conventionally, for example, as a heat exchanger for a car air conditioner, a plurality of flat tubes arranged in parallel at a predetermined interval in a thickness direction and interposed between these flat tubes. Arranged corrugated fins, and a pair of hollow headers arranged in a communication connection state at both ends of the tube, a type of heat exchange medium to simultaneously flow a plurality of tubes in parallel, It is rapidly becoming widespread in recent years, as it is compact and lightweight and can exhibit high performance.

However, when such a heat exchanger is used as, for example, an outdoor heat exchanger for a heat pump type room air conditioner, there is a problem in terms of frost resistance and it has not been put into practical use. Is.

As a measure for improving the frost resistance, for example, as disclosed in Japanese Patent Laid-Open No. 147785/1994, the leeward half of the corrugated fin is louverless, while the louver is formed on the leeward half. Things have been proposed. However, when such a corrugated fin is produced by using a fin roll forming machine having high productivity, the fin is meandered. Therefore, there is a problem that core setting is not easy at the time of assembling into the heat exchanger and mass productivity is hindered. Further, even if mass production is neglected and the core is set, the louver is formed in a state of being biased to one side of the corrugated fin, so that the buckling strength of the fin is weak and it is not easy to assemble the heat exchanger core. In addition, inconvenience may occur that brazing failure occurs between the corrugated fins and the flat tubes.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a heat exchanger excellent in both mass productivity and reliability and provided with anti-frosting measures. is there.

[0006]

In order to achieve the above object, a heat exchanger according to the present invention comprises a plurality of flat tubes arranged in parallel at a predetermined interval in a thickness direction and flat tubes thereof. In a heat exchanger comprising corrugated fins interposed between tubes and a pair of hollow headers arranged in communication connection at both ends of the tubes, the corrugated fins have a plurality of reinforcements on a windward side. While the ribs are formed, a plurality of louvers are formed in the same leeward side portion.

As a measure against drainage in this heat exchanger,
It is preferable that each of the flat tubes is arranged along the vertical direction and that one or a plurality of draining grooves are formed on the surface of the flat tube along the length direction thereof. Such a flat tube with a groove can be easily manufactured by extrusion molding.

Alternatively, instead of such a flat tube with a groove, each of the flat tubes may be arranged in the vertical direction, and a recess for draining water may be formed at the tube contact portion of the corrugated fin. good.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below.

1 to 4 show a first embodiment of the present invention. FIG. 1 shows a front view when the present invention is applied to an outdoor heat exchanger for a heat pump,
This heat exchanger (H) has a large number of perforated flat tubes (1
0), corrugated fins (14) interposed between the tubes (10), and a pair of headers (15) arranged in communication connection with both ends of the tubes (10).
(16) and are provided.

The flat tube (10) is made of an extruded aluminum material and is a porous flat tube having a partition and reinforcing wall (11) therein as shown in FIGS. 2 and 3. However, an electric resistance welded tube may be used instead of the extruded mold material. The tubes (10) are arranged vertically and arranged in the left-right direction at predetermined intervals in the thickness direction.

As shown in FIGS. 2 and 3, the surface of the tube (10) has a plurality of cross-sections V along its length.
Or, a U-shaped draining groove (12) is formed. This groove (12) is for allowing water droplets condensed on the tube surface to smoothly flow down along the groove (12) when the heat exchanger is used as an evaporator (evaporator).

In the illustrated embodiment, the draining groove (12) is formed at a corresponding position of each partition / reinforcing wall (11), but the forming position is not limited to this. Alternatively, for example, they may be formed between the partitions and the reinforcing walls.

The size of the draining groove (12) must be such that it exhibits good draining properties, does not significantly reduce the tube strength, and can secure the refrigerant passage (13) inside the tube. Needless to say. Preferably the groove radius is 0.5-1.0 mm
It is a degree.

The tube end has a header (15).
Tube insertion holes (15a) (16) formed in (16)
The inner peripheral edge of the tube insertion hole and the outer peripheral surface of the tube end must be integrated by brazing in a liquid-tight state. Therefore, in the tube (10) of the embodiment, the draining groove (12) is formed except for the end portion. However, the draining groove (12) may be formed in advance over the entire length of the tube (10), and the end portion of the tube may be subjected to a mouth straightening process to make the end portion flat without a groove. Such opening correction can be easily performed without increasing the processing time by adding the opening punch slide mechanism in the existing edge correction step.

As described above, by arranging the tube (10) vertically and forming the draining groove (12) on the surface thereof, the drainage of the condensed water is improved. The corrugated fins (14) are formed by corrugating a sheet material wider than the width of the flat tube (10). As the sheet material, for the purpose of facilitating the brazing integration with the flat tube (10) and the brazing integration, it is possible to use a brazing material on both front and back surfaces of a thin plate-shaped aluminum core material. Aluminum brazed sheets with layers clad are preferably used.

The corrugated fin (14) has a structure shown in FIG.
As shown in FIG. 4, a plurality of louvers (14a) are cut and raised in parallel along the fin height direction at a portion corresponding to the leeward side half of the flat tube (10). On the other hand, a plurality of reinforcing ribs (14b) having a semicircular cross section are formed along the fin height direction in the portion corresponding to the upper half of the wind. Such reinforcing ribs (14
b) can be easily formed by press molding. Then, the fins (14) are interposed between the tubes (10) adjacent to each other with the leeward side end aligned with the leeward side end of the tube (10), and are integrated by brazing. Such brazing is performed by the brazing material layer of the fin (14). Then, fin (1
The windward end of 4) is in a state of projecting to the windward side from the windward end of the tube (10).

The raised height (a) of the louver (14a) of the corrugated fin (14) and the reinforcing rib (14).
It is desirable that the size of b), that is, the radius (R) in the illustrated embodiment, has a relation of R> a in order to secure a free passage area between fins during frost formation. Further, the relationship between the size (R) of the reinforcing ribs (14b) and the number thereof is preferably set so that the size (R) and the number are the same as the residual stress when the louver (14a) is processed.

As described above, as the corrugated fins (14), only the reinforcing ribs (14b) are formed without forming the louvers in the windward half, and the louvers (14) are formed in the leeward half.
(a) is formed so that when the heat exchanger is operated as an evaporator (evaporator), a sufficient frosting region is secured and the operation time until slow frost is extended as long as possible. This is because

In this embodiment, the windward side of the corrugated fin (14) is projected to the windward side from the windward side end of the tube (10) to secure a larger frost formation region. Of course, it is also possible to adopt a corrugated fin (14) having the same width as the tube width without protruding in this way. Even in this case, it is possible to obtain the above effect more excellently than the case where the louver is formed over the entire width of the fin.
Further, as described above, by forming the reinforcing rib (14b) together with the louver (14a), meandering does not occur even when the corrugated fin (14) is formed by a fin roll forming machine, and core setting is easily performed. be able to. Moreover, since the buckling strength of the corrugated fins (14) is improved by the presence of the reinforcing ribs (14b), the heat exchanger core can be easily assembled, and the yield of brazing can be improved, and the quality can be improved. It is a thing.

The headers (15) and (16) are horizontally arranged at the upper and lower ends of the tube (10), and the ends of the tubes are communicatively connected.

The headers (15) and (16) are formed by bending one aluminum brazing sheet in which a brazing material layer is clad on the inner or outer surface of an aluminum core material, preferably on both surfaces, and bending it into a substantially circular cross section. The both side edges are butt-joined and brazed together by the brazing material layer. As the header constituent member, a clad tube in which an inner surface, an outer surface, or both inner and outer surfaces of an aluminum tube is coated with a brazing material layer is used. The clad tube may be manufactured by electric resistance welding, or may be manufactured by extrusion or other method.
The brazing filler metal layer generally has a Si content of about 6
About 13 wt% of Al-Si alloy is used.

Tube insertion holes (15a) are formed in the headers (15) and (16) at predetermined intervals along the length thereof.
(16a) is bored and the insertion hole (15a) is formed.
Corresponding end portions of the flat tubes (10) are inserted and arranged in (16a), and are joined and connected firmly and liquid-tightly by brazing.

In such brazing, the ends of the flat tubes (10) are inserted into the tube insertion holes (15a) (16a), and corrugated fins (14) are arranged between adjacent tubes. After the temporary assembly,
These are carried into a furnace and collectively brazed by vacuum brazing or the like for joining. After such brazing, the header (15) (16) and the flat tube (10)
A sufficient fillet is formed at the joint portion with and the headers (15) and (16) and the flat tube (10) are firmly joined and integrated without a gap, and each tube (10) and the corrugated fin (14). ) And are brazed together as well.

When brazing the headers (15) and (16) to the flat tube (10), a brazing sheet coated with brazing is used as the material for the corrugated fins (14), or the flat tube (10) is brazed. If a clad tube having a brazing material layer formed on the outer surface is used as a material, the flat tubes (10) and corrugated fins are simultaneously brazed to the headers (15) (16) and the flat tubes (10). Brazing with (14) can also be performed, and the productivity of the heat exchanger can be further improved.

Further, the closing lids (18), (18), (18) and (18) are provided at the left and right ends of the headers (15) and (16).
Are attached by brazing. Such brazing is performed by the brazing material layer coated on the headers (15) and (16) or the brazing material layer further coated on the lid body (18). Furthermore, on the left upper surface of the upper header (15)
The refrigerant inlet pipe (19) is connected by brazing so as to project upward, while the refrigerant outlet pipe (20) is connected by brazing at the lower right side of the lower header (16). This brazing is usually done with a braze layer coated on the headers (15) (16).

Although not shown in this embodiment, a corrugated fin may be further arranged on the outer surface of the outermost tube (10) and a side plate may be arranged outside the fin.

Although not used in this embodiment, a partition plate for partitioning the inside of the header in the longitudinal direction is provided in any one of the headers or both of the headers (15) and (16). By installing the plate, the refrigerant may flow in a meandering manner in all the refrigerant passages formed by the tube group.

In the above structure, the upper header (15)
The refrigerant flowing in from the refrigerant inlet pipe (19) of the first refrigerant flows into the upper header (15), then flows down each flat tube (10) to the lower header (16), and the refrigerant outlet pipe (2).
0) flows out of the heat exchanger. Then, while flowing through each tube (10), heat exchange is performed with the air flowing through the air flowing gap including the corrugated fins (14) formed between the flat tubes (10).

FIG. 5 shows a heat exchanger according to another embodiment.

The heat exchanger of this embodiment has the same basic structure as the heat exchanger of the above-mentioned embodiment,
Corresponding parts are designated by the same reference numerals, and detailed description thereof will be omitted. In this heat exchanger, instead of adopting the flat tube (10) in which the drainage groove is not formed as shown in the above embodiment, the flat tube (10) is replaced with the tube (10) as the corrugated fin (14). A radius of 0.3 to 1.2 mm at the contact part, that is, the center part of the mountain twill line
Draining recess (14c) of approximately U-shaped cross section
What has formed is adopted. This draining recess (14c) can be easily processed in the fin forming machine. Corrugated fins (1
Even if the draining concave portion (14c) is formed on the 4) side, the same operational effect as that of the above-described embodiment can be obtained. Further, there is an advantage that the drainability can be ensured even if a conventionally known extruded tube having no drainage groove is used as the flat tube (10).

However, the corrugated fins (14) in which the draining recesses (14c) as shown in this embodiment are formed and the flats in which the draining grooves (12) as shown in the above embodiment are formed. It goes without saying that the tube (10) may be combined.

Further, the present invention also allows the corrugated fins (14) in this embodiment to have the same width as the flat tubes (10).

FIG. 6 shows still another embodiment, but unlike the above-mentioned both embodiments, the flat tube (1
As 0), a meandering curve is adopted. The other points are the same as those of the above-described embodiments, and corresponding portions are denoted by the same reference numerals and the description thereof will be omitted.

In each of the above embodiments, the headers are arranged horizontally at the upper and lower positions.
The present invention is also applicable to a tube in which the tubes are horizontally arranged and headers are vertically arranged at both left and right ends thereof.

[0036]

As in the heat exchanger according to the present invention, a plurality of reinforcing ribs are formed on the leeward side of the corrugated fin, while a plurality of louvers are formed only on the leeward side. Similar to the conventional one in which the windward part of the corrugated fin is louverless, when the heat exchanger is operated as an evaporator (evaporator), a sufficient frosting region can be secured, and even slow frosting can be achieved. In addition to being able to lengthen the operating time as much as possible, it has the following effects. That is, since the reinforcing ribs are formed on the windward side of the corrugated fins, meandering does not occur even when the corrugated fins are formed by a fin roll forming machine, and core setting can be easily performed. Moreover, since the buckling strength of the corrugated fins is improved by the presence of the reinforcing ribs, the heat exchanger core can be easily assembled, the yield after brazing is improved, and the quality can be improved. .

As described above, according to the present invention, it is possible to provide a heat exchanger which is excellent in both mass productivity and reliability and which is protected against frost formation.

Further, by disposing the flat tubes along the vertical direction and forming one or a plurality of draining grooves along the length direction on the surface of the flat tubes, the drainage of the condensed water is improved. be able to.

Alternatively, by arranging the flat tubes along the vertical direction and forming the draining recesses at the tube contacting portions of the corrugated fins, the drainage of the condensed water can be improved similarly to the above. .

[Brief description of drawings]

FIG. 1 is an overall front view of a heat exchanger according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II in FIG.

FIG. 3 is a partially enlarged perspective view of a core portion of the heat exchanger.

FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG.

FIG. 5 is a partially enlarged perspective view of a core portion of a heat exchanger according to another embodiment.

FIG. 6 is an overall front view of a heat exchanger according to still another embodiment.

[Explanation of symbols]

 Reference Signs List 10 flat tube 12 groove for draining 14 corrugated fin 14a louver 14b reinforcing rib 14c recess for draining 15 header 16 header

Claims (3)

[Claims] 1. A plurality of flat tubes arranged in parallel in the thickness direction at predetermined intervals, corrugated fins interposed between the flat tubes, and a communication connection state at both ends of the tubes. In a heat exchanger having a pair of hollow headers arranged, the corrugated fins have a plurality of reinforcing ribs formed on the leeward side and a plurality of louvers formed on the leeward side. A heat exchanger characterized by being present. 2. The flat tube is arranged along the vertical direction, and one or a plurality of draining grooves are formed on the surface of the flat tube along the length direction thereof. Heat exchanger. 3. The heat exchanger according to claim 1, wherein the flat tubes are arranged along a vertical direction, and drainage recesses are formed at the tube contacting portions of the corrugated fins.