HEAT EXCHANGER, AIR-CONDITIONING APPARATUS EQUIPPED WITH HEAT EXCHANGER, AND METHOD FOR PRODUCING HEAT EXCHANGER

Abstract

A heat exchanger includes plural heat exchanger cores, each of which includes plural tabular fins with notches formed therein and plural heat transfer tubes. The plural fins are disposed such that planes of the fins face each other. The plural heat transfer tubes are hairpin tubes each of which is bent in a U-shape. The hairpin tubes are placed in the notches in the fins so as to extend in a direction crossing the planes of the fins. The plural heat exchanger cores are placed side by side in a direction crossing the direction of the notches in the fins and at the same time a direction along the planes of the fins. A brazing sheet is disposed between adjacent ones of the heat exchanger cores. The adjacent ones of the heat exchanger cores are brazed together by the brazing sheet.

Description

TECHNICAL FIELD

The present invention relates to a heat exchanger adapted to exchange heat between refrigerant and air, an air-conditioning apparatus equipped with the heat exchanger, and a method for producing the heat exchanger.

BACKGROUND ART

Hitherto, a finned-tube heat exchanger having heat transfer tubes and fins is known as a heat exchanger for an air-conditioning apparatus. Types of heat transfer tube include a circular tube whose cross-sectional shape is circular and a flat tube whose cross-sectional shape is a chamfered rectangle. Hereinafter, the heat exchanger using a circular tube will be referred to as a circular-tube heat exchanger and the heat exchanger using a flat tube will be referred to as a flat-tube heat exchanger.

As a method for producing a flat-tube heat exchanger, a method is known in which U-shaped notches extending in a widthwise direction of fins from one end of the fins are formed and a flat tube is press-fitted into the notches. On the other hand, a circular-tube heat exchanger is produced by forming circular holes in the fins and inserting a circular tube into the holes. In such a circular-tube heat exchanger, heat exchanger cores are not placed side by side in an up-down direction. On the other hand, a flat-tube heat exchanger is known in which plural heat exchanger cores are placed side by side in the up-down direction as described, for example, in Patent Literature 1.

CITATION LIST

Patent Literature

• Patent Literature 1: Japanese Patent No. 5980424

SUMMARY OF INVENTION

Technical Problem

Generally, in the flat-tube heat exchanger in which plural heat exchanger cores are placed side by side in the up-down direction, the adjacent heat exchanger cores are coupled together by a coupling element. Therefore, if a load is exerted on the flat-tube heat exchanger, there is concern that relative locations of the heat exchanger cores may be shifted due to falling of the coupling element or displacement between the coupling element and the heat exchanger.

The present invention has been made to solve the above problem and an object thereof is to provide a heat exchanger that keeps relative locations of heat exchanger cores from shifting, an air-conditioning apparatus equipped with the heat exchanger, and a method for producing the heat exchanger.

Solution to Problem

According to one embodiment of the present invention, there is provided a heat exchanger comprising a plurality of heat exchanger cores, each of the plurality of heat exchanger cores including a plurality of tabular fins with notches formed therein and a plurality of heat transfer tubes, wherein: the fins are disposed such that planes of the fins face each other and the heat transfer tubes are placed in the notches in the fins so as to extend in a direction crossing the planes of the fins; and the plurality of heat exchanger cores are placed side by side in a direction crossing the notches and extending along the planes of the fins, and adjacent ones of the heat exchanger cores are joined together.

Also, according to another embodiment of the present invention, there is provided a method for producing a heat exchanger that comprises a plurality of heat exchanger cores, each of the plurality of heat exchanger cores including a plurality of tabular fins with notches formed therein and a plurality of heat transfer tubes, the method comprising: forming the heat exchanger cores in which the fins are disposed such that planes of the fins face each other and that the heat transfer tubes are placed in the notches in the fins so as to extend in a direction crossing the planes of the fins; placing the plurality of heat exchanger cores side by side in a direction crossing a direction of the notches and extending along the planes of the fins; and joining together adjacent ones of the heat exchanger cores.

Advantageous Effects of Invention

In the heat exchanger according to one embodiment of the present invention, the plurality of heat exchanger cores are placed side by side in a direction crossing a direction of the notches formed in the fins and extending along the planes of the fins, and adjacent ones of the heat exchanger cores are joined together. This keeps relative locations of the adjacent heat exchanger cores from shifting.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1(a) and 1(b) are perspective views of an outdoor unit on which a flat-tube heat exchanger according to Embodiment 1 of the present invention is mounted.

FIG. 2 is a diagram showing a related art flat-tube heat exchanger mounted on an outdoor unit of an air-conditioning apparatus.

FIGS. 3(a) and 3(b) are diagrams showing the flat-tube heat exchanger according to Embodiment 1.

FIGS. 4(a) and 4(b) are sectional views of the flat-tube heat exchanger according to Embodiment 1.

FIGS. 5(a) to 5(e) are enlarged views of part D in FIG. 4(b).

FIGS. 6(a) and 6(b) are sectional views of a flat-tube heat exchanger according to Embodiment 2 of the present invention.

FIGS. 7(a) to 7(e) are enlarged views of part F in FIG. 6(b).

FIGS. 8(a) to 8(c) are sectional views of a flat-tube heat exchanger according to Embodiment 3 of the present invention.

FIGS. 9(a) to 9(c) are sectional views of a flat-tube heat exchanger according to Embodiment 4 of the present invention.

FIGS. 10(a) and 10(b) are sectional views of a flat-tube heat exchanger according to Embodiment 5 of the present invention before being loaded into an electric furnace.

FIGS. 11(a) and 11(b) are sectional views of a flat-tube heat exchanger according to Embodiment 6 of the present invention.

FIG. 12 is a diagram showing a flat-tube heat exchanger according to Embodiment 7 of the present invention.

FIGS. 13(a) and 13(b) are sectional views of the flat-tube heat exchanger according to Embodiment 7 of the present invention.

FIGS. 14(a) and 14(b) are diagrams showing a flat-tube heat exchanger according to Embodiment 8 of the present invention.

FIG. 15 is a diagram showing a flat-tube heat exchanger according to Embodiment 9 of the present invention.

FIG. 16 is a diagram showing one step in production of a heat exchanger core.

FIG. 17 is a diagram showing one step in production of the flat-tube heat exchanger.

FIG. 18 is a diagram showing one step in production of the flat-tube heat exchanger.

DESCRIPTION OF EMBODIMENTS

Embodiments of a heat exchanger according to the present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited by the embodiments described below. Also, in the following drawings, some components are not shown in their actual size relationships.

Embodiment 1

FIGS. 1(a) and 1(b) are perspective views of an outdoor unit on which a flat-tube heat exchanger according to Embodiment 1 of the present invention is mounted. FIG. 1(a) is a perspective view of the entire outdoor unit 200 and FIG. 1(b) is a perspective view showing the outdoor unit 200 from which some elements have been removed. Note that in FIGS. 1(a) and 1(b), an X direction corresponds to a front-rear direction of the outdoor unit 200, a Y direction corresponds to a left-right direction of the outdoor unit 200, and a Z direction corresponds to an up-down direction of the outdoor unit 200. The outdoor unit 200 has a vertically long outer shell as a whole. The outdoor unit 200 includes an upper front panel 51, a lower front panel 52, a left side panel 53, and a fan guard 54. Besides, the outdoor unit 200 also includes a back panel located on the back side, being opposite to the upper front panel 51 and lower front panel 52 as well as a right side panel located on the right side, being opposed to the left side panel 53. The back panel and the right side panel are located at positions not illustrated in FIG. 1. The upper front panel 51 and the lower front panel 52 make up front part of the outer shell of the outdoor unit 200. The left side panel 53 makes up left part of the outer shell of the outdoor unit 200. The right side panel makes up right part of the outer shell of the outdoor unit 200. The back panel makes up back part of the outer shell of the outdoor unit 200. The fan guard 54 is provided above the outdoor unit 200.

An air inlet 59 is formed in the left side panel 53. Air inlets similar to the air inlet 59 are formed also in the back panel and the right side panel. An air outlet 55 is formed in the fan guard 54.

As shown in FIG. 1(b), the outdoor unit 200 includes a base panel 56 disposed at the bottom. The base panel 56 makes up a bottom part of the outer shell of the outdoor unit 200. A flat-tube heat exchanger 101, a compressor 57, and an accumulator 58 are disposed on the base panel 56. The flat-tube heat exchanger 101, compressor 57, and accumulator 58 are fixed to the base panel 56, for example, by screwing.

The flat-tube heat exchanger 101 is disposed such that it faces the left side panel 53, the back panel, and the right side panel. That is, the flat-tube heat exchanger 101 is U-shaped in cross section in a plane parallel to the X direction and the Y direction. The flat-tube heat exchanger 101 is fixed to the left side panel 53 as well as to the base panel 56 as described above. Refrigerant is supplied to the flat-tube heat exchanger 101. Also, air taken in through the air inlets in the rear panel and the right side panel as well as through the air inlet 59 passes through the flat-tube heat exchanger 101. The flat-tube heat exchanger 101 exchanges heat between the refrigerant and passing air. During cooling operation of an air-conditioning apparatus connected with the outdoor unit 200, the flat-tube heat exchanger 101 functions as a condenser, i.e., as a radiator, and thereby condenses and liquefies the refrigerant. Also, during heating operation of the air-conditioning apparatus connected with the outdoor unit 200, the flat-tube heat exchanger 101 functions as an evaporator, and thereby evaporates or vaporizes the refrigerant.

The compressor 57 compresses and discharges refrigerant. The compressor 57 is connected to a suction side of the accumulator 58. The accumulator 58 serves to accumulate liquid refrigerant. The compressor 57 is connected to a discharge side to the flat-tube heat exchanger 101 during cooling operation of the air-conditioning apparatus connected with the outdoor unit 200 and is connected to a use side heat exchanger mounted on a non-illustrated indoor unit, during heating operation of the air-conditioning apparatus.

Also, a non-illustrated fan is mounted on the outdoor unit 200 and is used to take air into the outdoor unit 200 and discharge air out of the outdoor unit 200. The fan is disposed on top of the outdoor unit 200 and is surrounded and covered by the fan guard 54. As the fan rotates, air is taken into the outdoor unit 200 through the air inlets in the rear panel and the right side panel as well as through the air inlet 59 while air in the outdoor unit 200 is released out of the outdoor unit 200 through the air outlet 55.

FIGS. 3(a) and 3(b) are diagrams showing the flat-tube heat exchanger according to Embodiment 1. FIG. 3(a) is a general view of the flat-tube heat exchanger 101 before being bent into a U-shape. FIG. 3(b) is an enlarged view of part B in FIG. 3(a), i.e., hairpin-like bent portion of flat tubes of the flat-tube heat exchanger 101. The flat-tube heat exchanger 101 includes two heat exchanger cores 11 and 12. Each of the heat exchanger cores 11 and 12 includes hairpin tubes 1, which are U-bent flat heat transfer tubes, and plural fins. The plural fins are disposed in parallel such that planes of each pair of adjacent fins face each other. In FIG. 3, the plural fins are illustrated as a fin assembly 3. Of the plural fins, a U-shaped notch is formed along a widthwise direction of each fin in one of a pair of lateral edges extending in a lengthwise direction. The hairpin tubes 1 are press-fitted into the U-shaped notches in the plural fins. U-bent portions of the hairpin tubes 1 are located in one of end portions of each heat exchanger core 11 or 12. The end portions of the hairpin tubes 1 that are located at another end of each heat exchanger core 11 or 12, are cut sections that allow cross-sectional shape of the flat-tubes to be checked visually. The cut sections of the hairpin tubes 1 are connected with non-illustrated joints used to connect flat tubes and circular tubes with each other, a header 5, and a distributor 6.

In the following description, a stage direction means a direction crossing a direction of the notches in the fins and at the same time a direction extending along the planes of the fins. That is, the stage direction is an up-down direction of the flat-tube heat exchanger 101 and corresponds to the Z direction in FIG. 1.

The two heat exchanger cores 11 and 12 are placed side by side in the stage direction. In other words, the two heat exchanger cores 11 and 12 are placed side by side along the up-down direction. The heat exchanger cores 11 and 12 are joined together by a brazing sheet 7. The heat exchanger cores 11 and 12 abut against each other in the stage direction and loaded into an electric furnace with a brazing sheet 7 inserted therebetween, thereby being brazed to each other.

According to Embodiment 1, the heat exchanger cores 11 and 12 are placed side by side in the stage direction and joined together using a brazing sheet 7. Thus, even if a load is exerted on the flat-tube heat exchanger 101, relative positional locations of the heat exchanger cores 11 and 12 can be prevented from shifting.

Also, since it is sufficient that the two heat exchanger cores 11 and 12 are abut against each other and loaded into an electric furnace with a brazing sheet 7 inserted therebetween, the flat-tube heat exchanger 101 is easy to assemble during production. Also, production time and production cost of the flat-tube heat exchanger 101 can be curbed.

Now, effects of the heat exchanger according to Embodiment 1 will be described in comparison with an existing heat exchanger.

FIG. 2 is a diagram showing an existing flat-tube heat exchanger mounted on an outdoor unit of an air-conditioning apparatus. In FIG. 2, components similar to those of the flat-tube heat exchanger 101 of Embodiment 1 described with reference to FIG. 3 are denoted by the same reference numerals as the corresponding components in FIG. 3, and description thereof will be omitted. The existing flat-tube heat exchanger 100 includes heat exchanger cores 111 and 10. Each of the heat exchanger cores 111 and 10 includes fin assemblies 3. The heat exchanger cores 111 and 10 are coupled together and fixed by coupling elements 4 placed at intervals in a direction crossing planes of fins in the fin assemblies 3. The coupling elements 4 are fitted around hairpin tubes 1 and this configuration fixes the heat exchanger cores 111 and 10 to each other. In some cases, the coupling elements 4 are fixed to the hairpin tubes 1 with an adhesive.

In the existing flat-tube heat exchanger 100 of FIG. 2, the coupling elements 4 coupling together the heat exchanger cores 111 and 10 are placed at intervals in the direction crossing the planes of fins in the fin assemblies 3. Thus, fins cannot be placed in locations where the coupling elements 4 are placed. That is, in the direction in which the hairpin tubes 1 extend by passing through fins, fins do not exist in some part. In contrast, according to Embodiment 1, since the two heat exchanger cores 11 and 12 are placed side by side in the stage direction, fins can be placed anywhere in the direction in which the hairpin tubes 1 extend by passing through fins. In this way, Embodiment 1 allows a larger number of fins to be placed as compared with the existing example. This ensures high heat exchange characteristics of the flat-tube heat exchanger 101.

FIGS. 4(a) and 4(b) are sectional views of the flat-tube heat exchanger according to Embodiment 1. FIG. 4(a) is a sectional view of the flat-tube heat exchanger along line A-A in FIG. 3(a) and FIG. 4(b) is a sectional view along line C-C in FIG. 4(a). The lateral direction in FIGS. 4(a) and 4(b) coincides with the stage direction in the figures. As shown in FIG. 4(b), the end faces of fins 211 of the heat exchanger core 11 that face the heat exchanger core 12 are not bent, and the end faces of fins 212 of the heat exchanger core 12 that face the heat exchanger core 11 are not bent. Besides, a brazing sheet 7 is inserted between the heat exchanger cores 11 and 12 as described above. That is, the brazing sheet 7 is interposed between the unbent end faces of the fins.

Now, combinations of materials for the fins 2, hairpin tubes 1, and brazing sheet 7 according to Embodiment 1 will be described. A first combination uses a bare material for the fins 2, uses a clad tube for the hairpin tubes 1, and does not use a brazing material for brazing between the fins 2 and the hairpin tubes 1. A second combination uses a clad material for the fins 2, uses a bare tube for the hairpin tubes 1, and does not supply a brazing material for brazing between the fins 2 and hairpin tubes 1. A third combination, which uses preplaced brazing, uses a bare material for the fins 2, uses a bare tube for the hairpin tubes 1, and supplies a brazing material for brazing between the fins 2 and the hairpin tubes 1. Here, the bare material is a material made up of a core and the clad material is a material made by bonding together a core and a brazing material. The bare tube is a flat tube without a brazing material provided on a surface and the clad tube is a flat tube having a brazing material layer on its surface.

The first combination uses a clad tube for the hairpin tubes 1, i.e., for the flat tubes. The use of the clad tube for the hairpin tubes 1 makes it possible to use a bare material that does not need a brazing material layer, for the fins 2. An aluminum brazing material contains Si, i.e., silicon. Because Si has very high hardness, there is a concern that wear on an edge of a cutting blade of a metal die used in forming the fins 2 may be accelerated. The use of a bare material that does not need a brazing material for the fins 2 can reduce the wear on the edge of the cutting blade.

The second combination uses a clad material for the fins 2. The use of a clad material for the fins 2 makes it possible to use a bare material made up of only a core for the hairpin tubes 1, thus leading to reduction in cost.

The third combination uses bare materials for the fins 2 and the hairpin tubes 1 and uses preplaced filler metal. The preplaced filler metal is a brazing material set near brazing points before being loaded into an electric furnace to supply the brazing material to between workpieces to be brazed during brazing. Preplaced filler metal makes it easy to adjust and change the amount of the brazing material and the use of preplaced filler metal exerts the effect of reducing wear on the edge of the cutting blade of the metal die. Thus, the use of preplaced filler metal allows the production cost of the heat exchanger cores 11 and 12 to be curbed.

FIGS. 5(a) to 5(e) are enlarged views of part D in FIG. 4(b). FIG. 5 shows the flat-tube heat exchanger at a stage before being loaded into an electric furnace. FIG. 5(a) is an example in which a bare material made up of only a core 2a is used for the fins 2 and a brazing material 7b is used for the brazing sheet 7. The use of a bare material made up of only the core 2a for the fins 2 exerts the effect of suppressing wear on the edge of the cutting blade. The use of the brazing material 7b for the brazing sheet 7 improves designability of joins because the brazing sheet 7 is melted after being loaded into the electric furnace.

FIG. 5(b) is an example in which a clad material made up of the core 2a and a brazing material 2b is used for the fins 2 and a brazing material is used for the brazing sheet 7. Since a clad material made up of the brazing material 2b is used for the fins 2, a bare tube can be used for the hairpin tubes 1. The use of a bare tube allows the production cost of the heat exchanger cores 11 and 12 to be curbed. Also, the use of the brazing sheet 7 improves the designability of joins as in the case of the example of FIG. 5(a).

FIG. 5(c) is an example in which a clad material made up of the core 2a and the brazing material 2b is used for the fins 2 and a bare material made up of only the core 7a is used for the brazing sheet 7. By supplying the brazing material used for brazing between the fins 2 and the brazing sheet 7 from the brazing material 2b of the fins 2, a bare material can be used for the brazing sheet 7. This makes it possible to curb the cost of the brazing sheet 7. Since a metal junction is formed between the fins 2 and the brazing sheet 7 by brazing, the heat transfer area of the fins 2 is increased. This improves heat exchange performance of the heat exchanger cores 11 and 12.

FIG. 5(d) is an example in which a bare material made up of only the core 2a is used for the fins 2 and a clad material made up of the core 7a and the brazing material 7b formed on a surface of the core 7a is used for the brazing sheet 7. The use of a bare material for the fins 2 exerts the effect of suppressing wear on the edge of the cutting blade. Since a clad material is used for the brazing sheet 7, the core of the brazing sheet 7 remains after being loaded into the electric furnace, brazing the fins 2 and the brazing sheet 7 to each other and forming a metal junction. This increases the heat transfer area of the fins 2, thereby improving heat exchange performance of heat exchangers of the heat exchanger cores 11 and 12.

FIG. 5(e) is an example in which a clad material made up of the core 2a and the brazing material 2b is used for the fins 2 and a clad material made up of the core 7a and the brazing material 7b formed on the surface of the core 7a is used for the brazing sheet 7. The core of the brazing sheet 7 remains after being loaded into the electric furnace, brazing the fins 2 and the brazing sheet 7 to each other and forming a metal junction. This increases the heat transfer area of the fins 2, thereby improving heat exchange performance of heat exchangers of the heat exchanger cores 11 and 12. Also, a larger amount of the brazing material is supplied to the brazing points, which eliminates the lack of brazing material and thereby enabling stable brazing.

Note that although in Embodiment 1, the brazing sheet 7 is joined by brazing, this is not restrictive. The brazing sheet 7 may be joined with an adhesive. Also, the brazing between the fins 2 and hairpin tubes 1 may be performed during brazing between the heat exchanger cores 11 and 12 performed using the brazing sheet 7, or in another step before the brazing between the heat exchanger cores 11 and 12 performed using the brazing sheet 7. Also, brazing of the header 5 and the distributor 6 may be performed all at once by loading the header 5 and the distributor 6 into the electric furnace at the time of brazing of the heat exchanger cores performed using the brazing sheet 7. The header 5 and the distributor 6 may be brazed in separate steps before and after brazing between the heat exchanger cores.

Embodiment 2

FIGS. 6(a) and 6(b) are sectional views of a flat-tube heat exchanger according to Embodiment 2 of the present invention. FIG. 6(a) is a sectional view of the flat-tube heat exchanger according to Embodiment 2 along a line corresponding to line A-A in FIG. 3(a) and FIG. 6(b) is a sectional view along line E-E in FIG. 6(a). The lateral direction in FIGS. 6(a) and 6(b) coincides with the stage direction in the figures.

As shown in FIGS. 6(a) and 6(b), heat exchanger cores 112 and 122 are placed side by side in the stage direction. As shown in FIG. 6(b), those end faces of fins 221 of the heat exchanger core 112 that face the heat exchanger core 122 are bent, forming fin collars 8. Similarly, the end faces of fins 222 of the heat exchanger core 122 that face the heat exchanger core 112 are bent, forming fin collars 8. That is, on the heat exchanger cores 112 and 122 that abut against each other, the end faces of the fins 221 and 222 of the heat exchanger cores 112 and 122 are bent ata part where the heat exchanger cores 112 and 222 abut against each other. A brazing sheet 7 is inserted between the heat exchanger cores 112 and 122. That is, the brazing sheet 7 is interposed between the bent end faces of the fins 221 and bent end faces of the fins 222.

According to Embodiment 2, since the brazing sheet 7 is interposed between the bent end faces of the fins 221 and 222, a wider contact area can be secured between the fins 221 and brazing sheet 7 as well as between the fins 222 and brazing sheet 7. Thus, the brazing sheet 7 can be brazed stably to the fins 221 and 222. Also, brazing joint strength of the brazing sheet 7 with the fins 221 and 222 is increased.

FIGS. 7(a) to 7(e) are enlarged views of part F in FIG. 6(b). FIG. 7 shows the flat-tube heat exchanger at a stage before being loaded into an electric furnace. FIG. 7(a) is an example in which a bare material made up of only the core 2a is used for the fins 221 and 222 and the brazing material 7b is used for the brazing sheet 7. The use of a bare material for the fins 221 and 222 exerts the effect of suppressing wear on the edge of the cutting blade of the metal die. Also, the use of the brazing material 7b for the brazing sheet 7 improves designability of joins because the brazing sheet 7 is melted after being loaded into the electric furnace. Furthermore, on the heat exchanger cores 112 and 122, end faces of the fins 221 and 222 of the heat exchanger cores 112 and 122 are bent at a part where the heat exchanger cores 112 and 122 abut against each other, and the fin collars 8 are formed on the fins 221 and 222, thereby exerting the above-mentioned effect.

FIG. 7(b) is an example in which a clad material made up of the core 2a and brazing material 2b is used for the fins 221 and 222 and a brazing material is used for the brazing sheet 7. Since a clad material made up of the brazing material 2b is used for the fins 221 and 222, a bare tube can be used for the hairpin tubes 1. The use of a bare tube allows the production cost of the heat exchanger cores 112 and 122 to be curbed. Also, the use of the brazing sheet 7 improves the designability of joins. Also, a large amount of the brazing material is supplied to the brazing points, which eliminates the lack of a brazing material during joining, and thereby enabling stable brazing.

FIG. 7(c) is an example in which a clad material is used for the fins 221 and 222 and a bare material made up of only the core 7a is used for the brazing sheet 7. By supplying the brazing material used to braze the brazing sheet 7 to the fins 221 and 222 from a brazing material layer of the fins 221 and 222, a bare material can be used for the brazing sheet 7. This makes it possible to curb the cost of the brazing sheet 7. Since the brazing sheet 7 is brazed to the fins 221 and 222, forming a metal junction, the heat transfer area of the fins 221 and 222 is increased, which improves the heat exchange performance of the flat-tube heat exchangers. Furthermore, on the heat exchanger cores 112 and 122, the end faces of the fins 221 and 222 of the heat exchanger cores 112 and 122 are bent at a part where the heat exchanger cores 112 and 122 abut against each other, and fin collars 8 are formed on the fins 221 and 222, thereby exerting the above-mentioned effect.

FIG. 7(d) is an example in which a bare material made up of only the core 2a is used for the fins 221 and 222 and a clad material made up of the core 7a and the brazing material 7b formed on the surface of the core 7a is used for the brazing sheet 7. The use of a bare material for the fins 221 and 222 exerts the effect of suppressing wear on the edge of the cutting blade of the metal die. Since a clad material is used for the brazing sheet 7, the core of the brazing sheet 7 remains after being loaded into the electric furnace, brazing the brazing sheet 7 to the fins 221 and 222 and forming a metal junction. This increases the heat transfer area of the fins 221 and 222, thereby improving the heat exchange performance of the heat exchanger cores 112 and 122. Furthermore, on the heat exchanger cores 112 and 122, the end faces of the fins 221 and 222 of the heat exchanger cores 112 and 122 are bent at a part where the heat exchanger cores 112 and 122 abut against each other, and fin collars 8 are formed on the fins 221 and 222, thereby exerting the above-mentioned effect.

FIG. 7(e) is an example in which a clad material made up of the core 2a and brazing material 2b is used for the fins 221 and 222 and a clad material made up of the core 7a and the brazing material 7b formed on the surface of the core 7a is used for the brazing sheet 7. The core of the brazing sheet 7 remains after being loaded into the electric furnace, brazing the brazing sheet 7 to the fins 221 and 222 and forming a metal junction. This increases the heat transfer area of the fins 221 and 222, thereby improving the heat exchange performance of the heat exchanger cores 112 and 122. Also, a larger amount of the brazing material is supplied to the brazing points, which eliminates the lack of a brazing material and thereby enabling stable brazing. Furthermore, on the heat exchanger cores 112 and 122, the end faces of the fins 221 and 222 of the heat exchanger cores 112 and 122 are bent ata part where the heat exchanger cores 112 and 122 abut against each other, and fin collars 8 are formed on the fins 221 and 222, thereby exerting the above-mentioned effect.

Embodiment 3

FIGS. 8(a) to 8(c) are sectional views of a flat-tube heat exchanger according to Embodiment 3 of the present invention. FIG. 8(a) is a sectional view of the flat-tube heat exchanger according to Embodiment 3 along a line corresponding to line A-A in FIG. 3(a). That is, FIG. 8(a) shows a section of the flat-tube heat exchanger according to Embodiment 3 in the stage direction. FIG. 8(b) is a sectional view along line G-G in FIG. 8(a). The lateral direction in FIGS. 8(a) and 8(b) coincides with the stage direction in the figures. FIG. 8(c) is an enlarged view of part H in FIG. 8(b). FIG. 8(c) shows the flat-tube heat exchanger at a stage before being loaded into an electric furnace. As shown in FIGS. 8(a) and 8(b), heat exchanger cores 311 and 312 are placed side by side in the stage direction. As shown in FIG. 8(c), according to Embodiment 3, a clad material made up of the core 2a and brazing material 2b is used for the fins 231 of the heat exchanger core 311 and the fins 232 of the heat exchanger core 312. No brazing sheet is disposed between the heat exchanger cores 311 and 312. When the two heat exchanger cores 311 and 312 are loaded into the electric furnace while abutting against each other, the brazing material 2b of the fins 231 and 232, which are made of a clad material, flows into a gap between the cores 2a by capillary action, thereby forming a brazed joint. Since no brazing sheet is disposed, the flat-tube heat exchanger is easy to assemble during production, which results in a reduction in production time and production cost.

Embodiment 4

FIGS. 9(a) to 9(c) are sectional views of a flat-tube heat exchanger according to Embodiment 4 of the present invention. FIG. 9(a) is a sectional view of the flat-tube heat exchanger according to Embodiment 4 along a line corresponding to line A-A in FIG. 3(a). That is, FIG. 9(a) shows a section of the flat-tube heat exchanger according to Embodiment 4 in the stage direction. FIG. 9(b) is a sectional view along line I-I in FIG. 9(a). The lateral direction in FIGS. 9(a) and 9(b) coincides with the stage direction in the figures. FIG. 9(c) is an enlarged view of part J in FIG. 9(b). FIG. 9(c) shows the flat-tube heat exchanger at a stage before being loaded into an electric furnace. As shown in FIG. 9(c), the end faces of fins 241 of the heat exchanger core 411 facing the heat exchanger core 412 are bent, and the end faces of fins 242 of the heat exchanger core 412 facing the heat exchanger core 411 are also bent. That is, on the heat exchanger cores 411 and 412 abutting against each other, the fins 241 and fins 242 are bent at a part where the heat exchanger cores 411 and 412 abut against each other. The brazing sheet 7 is not disposed between the heat exchanger cores 411 and 412.

When the two heat exchanger cores 411 and 412 are loaded into the electric furnace while abutting against each other, the brazing material 2b of the fins 241 and 242, which are made of a clad material, flows into a gap between the cores 2a by capillary action, thereby forming a brazed joint. Since no brazing sheet is disposed, the flat-tube heat exchanger is easy to assemble during production, which results in reduced production time and production cost. Furthermore, on the heat exchanger cores 411 and 412, the end faces of the fins 241 and 242 of the heat exchanger cores 411 and 412 are bent at a part where the heat exchanger cores 411 and 412 abut against each other, thereby forming fin collars 8. Thus, a wider contact area can be secured between the fins 241 of the heat exchanger core 411 and the fins 242 of the heat exchanger core 412. Consequently, the fins 241 and 242 can be brazed stably to each other. Also, brazing joint strength between the fins 241 and 242 is increased.

Embodiment 5

FIGS. 10(a) and 10(b) are sectional views of a flat-tube heat exchanger according to Embodiment 5 of the present invention before being loaded into an electric furnace. FIG. 10(a) is a sectional view of the flat-tube heat exchanger according to Embodiment 5 along a line corresponding to line A-A in FIG. 3(a). That is, FIG. 10(a) shows a section of the flat-tube heat exchanger according to Embodiment 5 in the stage direction. FIG. 10(b) is a sectional view along line K-K in FIG. 10(a). The lateral direction in FIGS. 10(a) and 10(b) coincides with the stage direction in the figures. In Embodiment 5, heat exchanger cores 511 and 512 are placed side by side in the stage direction. Hairpin tubes 1 are exposed on end faces of fins 252 at a part where the heat exchanger core 512 abuts against the heat exchanger core 511. End faces of fins 251 are bent at a part where the heat exchanger core 511 abuts against the heat exchanger core 512. A brazing sheet 7 is inserted between the heat exchanger cores 511 and 512. The brazing sheet 7 of Embodiment 5 is made up of only a brazing material. According to Embodiment 5, the hairpin tubes 1 of the heat exchanger core 512 and the fins 251 of the heat exchanger core 511 are brazed together. Generally, flat tubes are more rigid and hardly deformed as compared with fins. Thus, brazing according to Embodiment 5 is more stable than when one group of fins and another group of fins are brazed to each other.

Embodiment 6

FIGS. 11(a) and 11(b) are sectional views of a flat-tube heat exchanger according to Embodiment 6 of the present invention. FIG. 11(a) is a sectional view of the flat-tube heat exchanger according to Embodiment 6 along a line corresponding to line A-A in FIG. 3(a). That is, FIG. 11(a) shows a section of the flat-tube heat exchanger according to Embodiment 6 in the stage direction. FIG. 11(b) is a sectional view along line L-L in FIG. 11(a). The lateral direction in FIGS. 11(a) and 11(b) coincides with the stage direction in the figures. In Embodiment 6, heat exchanger cores 611 and 612 are placed side by side in the stage direction. Hairpin tubes 1 are exposed on end faces of fins 262 at a part where the heat exchanger core 612 that abuts the heat exchanger core 611. End faces of fins 261 are bent ata part where the heat exchanger core 611 abuts against the heat exchanger core 612. A clad material made up of a core and brazing material is used for the fins 261 and 262. No brazing sheet is disposed between the heat exchanger cores 611 and 612. According to Embodiment 6, the hairpin tubes 1 of the heat exchanger core 612 and the fins 261 of the heat exchanger core 611 are brazed together. Thus, as in the case of Embodiment 5, more stable brazing is ensured when one group of fins and another group of fins are brazed to each other. Also, the use of a clad material for the fins 261 and 262 eliminates the need for a brazing sheet, making it possible to reduce the number of parts.

Embodiment 7

FIG. 12 is a diagram showing a flat-tube heat exchanger according to Embodiment 7 of the present invention. FIG. 12 is a general view of the flat-tube heat exchanger 107 before being bent into a U-shape. FIGS. 13(a) and 13(b) are sectional views of the flat-tube heat exchanger according to Embodiment 7 of the present invention. FIG. 13(a) is a sectional view of the flat-tube heat exchanger according to Embodiment 7 along a line corresponding to line M-M in FIG. 12(a). That is, FIG. 13(a) shows a section of the flat-tube heat exchanger according to Embodiment 7 in the stage direction. FIG. 13(b) is a sectional view along line N-N in FIG. 13(a). The lateral direction in FIGS. 13(a) and 13(b) coincides with the stage direction in the figures. In Embodiment 7, heat exchanger cores 711 and 712 are placed side by side in the stage direction. Hairpin tubes 1 are exposed on end faces of fins 271 at a part where the heat exchanger core 711 of the flat-tube heat exchanger 107 abuts against the heat exchanger core 712. Similarly, hairpin tubes 1 are exposed on end faces of fins 272 at a part where the heat exchanger core 712 of the flat-tube heat exchanger 107 abuts against the heat exchanger core 711. At least two spacer blocks 9 are disposed between the heat exchanger cores 711 and 712. Five spacer blocks 9 are disposed in the example shown in FIG. 12. The spacer blocks 9 are made of metal such as aluminum or stainless steel.

When plural spacer blocks 9 are inserted between the heat exchanger cores 711 and 712 and loaded into the electric furnace by being placed in contact with hairpin tubes 1 made of a clad tube having a brazing material layer, the heat exchanger cores 711 and 712 are joined together via the hairpin tubes 1 and the spacer blocks 9. According to Embodiment 7, since the hairpin tubes 1 and the spacer blocks 9, both having rigidity, are joined together, stable brazing can be achieved and coupling strength can be increased as well.

Whereas five spacer blocks 9 are disposed in the example shown in FIG. 13, this is not restrictive. It is sufficient that two or more spacer blocks 9 are disposed. Note that a brazing material may be supplied instead of the clad tube or spacer blocks 9 provided with a brazing material may be used. Also, the joint between the hairpin tubes 1 and the spacer blocks 9 is not limited to brazing, and an adhesive may be used.

Embodiment 8

FIGS. 14(a) and 14(b) are diagrams showing a flat-tube heat exchanger according to Embodiment 8 of the present invention. FIG. 14(a) is a general view of the flat-tube heat exchanger 108 before being bent into a U-shape. FIG. 14(b) is an enlarged view of part O in FIG. 14(a), i.e., hairpin bends of flat tubes of the flat-tube heat exchanger 108. The flat-tube heat exchanger 108 includes heat exchanger cores 281 and 282. The heat exchanger cores 281 and 282 are placed side by side in the stage direction. The heat exchanger cores 281 and 282 include plural fins. The plural fins are disposed in parallel such that the planes of each pair of adjacent fins face each other. In FIG. 14, the plural fins are illustrated as a fin assembly 3. Of the plural fins, a U-shaped notch is formed along a widthwise direction of each fin in one of a pair of lateral edges extending in a lengthwise direction. The hairpin tubes 1 are press-fitted into the U-shaped notches in the plural fins. According to Embodiment 8, one of the U-bent hairpin tubes 1 is placed so as to bridge between the heat exchanger cores 281 and 282. That is, one of a pair of straight-tube portions of the hairpin tubes extending in the lateral direction of the flat-tube heat exchanger 108 is placed at a part in the heat exchanger core 281 that is closest to the end face facing the heat exchanger core 282 while another straight-tube portion is placed at a part in the heat exchanger core 282 that is closest to the end face facing the heat exchanger core 281. The hairpin tubes 1 are placed so as to couple together the heat exchanger cores 281 and 282. Besides, a brazing sheet 7 is inserted between the heat exchanger cores 281 and 282. The heat exchanger cores 281 and 282 are joined together by the brazing sheet 7.

When a flat-tube heat exchanger is configured by coupling together two heat exchanger cores, the join between the two heat exchanger cores is lower in strength than other parts. There is a concern that if a load is exerted on the flat-tube heat exchanger, the heat exchanger cores may be divided along the join. According to Embodiment 8, cut ends of the hairpin tubes 1 are connected with the header 5 and the hairpin side bridges between the heat exchanger cores 281 and 282. This further increases the strength of the join between the heat exchanger cores 281 and 282. Also, there is no need to provide an element configured to increase the strength of the join. This enables increasing the strength of the join while curbing increases in the number of parts. In this way, Embodiment 8 makes it possible to facilitate assembly and reduce the production cost while increasing the strength of the join between the two heat exchanger cores.

Embodiment 9

FIG. 15 is a diagram showing a flat-tube heat exchanger according to Embodiment 9 of the present invention. FIG. 15 is a general view of the flat-tube heat exchanger 109 before being bent into a U-shape. The flat-tube heat exchanger 109 includes heat exchanger cores 291 and 292. The heat exchanger cores 291 and 292 are placed side by side in the stage direction. The heat exchanger cores 291 and 292 include plural fins. The plural fins are disposed in parallel such that the planes of each pair of adjacent fins face each other. In FIG. 15, the plural fins are illustrated as a fin assembly 3. Of the plural fins, a U-shaped notch is formed along a widthwise direction of each fin in one of a pair of lateral edges extending in a lengthwise direction. Flat tubes 15 are press-fitted into the U-shaped notches in the plural fins. According to Embodiment 9, one of cut ends of each flat tube 15 is connected with a header 5 and another cut end is also connected with a header 5. That is, both ends of each flat tube 15 are connected with respective headers 5.

As described above, when a flat-tube heat exchanger is configured by coupling together two heat exchanger cores, the join between the two heat exchanger cores is lower in strength than other parts. According to Embodiment 9, since the both ends of the hairpin tubes 1 are connected with the respective headers 5, the strength of the join between the heat exchanger cores 291 and 292 can be increased.

Whereas Embodiments 1 to 9 are described above by exemplifying a configuration in which two heat exchanger cores are placed side by side in the stage direction and joined together, this is not restrictive. Three or more heat exchanger cores may be placed side by side in the stage direction, with adjacent heat exchanger cores being joined together.

According to the present invention, since plural heat exchanger cores are placed side by side in the stage direction, although the individual heat exchanger cores are small, a large flat-tube heat exchanger can be constructed as a whole. By reducing the size of the heat exchanger cores, production equipment of the heat exchanger cores can be downsized, which makes it possible to reduce capital investment. Also, by adjusting the number of heat exchanger cores placed side by side in the stage direction, flat-tube heat exchangers of various sizes can be produced easily.

Embodiment 10

Next, a method for producing a flat-tube heat exchanger will be described. As described above, the flat-tube heat exchanger 101 includes the heat exchanger core 11, the heat exchanger core 12, non-illustrated joints used to connect flat tubes and circular tubes with each other, the header 5, and the distributor 6. Also, the heat exchanger cores 11 and 12 include the hairpin tubes 1 produced by bending flat tubes as well as include plural fins.

Methods for producing a heat exchanger core include the following. The fins of heat exchanger cores are cut and created from a metal sheet, such as an aluminum sheet, with high thermal conductivity. The fins are created, for example, by press-forming a coiled aluminum sheet continuously fed by a progressive die mounted on a high-speed press. To make it easier to join fins to flat tubes, each of the fins may be provided with a fin collar formed by cutting and raising part of a fin surface placed in contact with the flat tubes. The flat tubes are made of metal, such as aluminum or copper, with high thermal conductivity. The hairpin tubes are created as follows: a flat tube coiled by being wound around a bobbin is rolled, shaped by being straightened, cut into a predetermined length, and bent.

The press-formed fins are cut into a predetermined length and stacked. Bent flat tubes or hairpin tubes are press-fitted into the U-shaped notches in the stacked fins to produce the heat exchanger core.

Methods for producing a heat exchanger core include a method different from the above-mentioned press-fitting method as follows. FIG. 16 is a diagram showing one step in production of a heat exchanger core according to Embodiment 10 of the present invention. As shown in FIG. 16, fins 2 are cut one by one from a sheet material 20 press-formed by continuously feeding a material by a progressive die mounted on a high-speed press. Then, plural hairpin tubes 1 are arranged and the fins 2 are inserted one by one into the plural hairpin tubes 1 such that the hairpin tubes 1 are placed in the notches in the fins 2. Consequently, the fins 2 are arranged such that the planes of the fins 2 face each other. Note that rather than the hairpin tubes 1 in which flat tubes are bent, straight, flat tubes may be used without being bent.

Next, the flat tubes, i.e., the hairpin tubes 1, are brazed to the fins 2. In the case of the flat-tube heat exchanger according to Embodiment 1, the material composition of the fins 2 is as described with reference to FIGS. 5(a) to 5(e). As with FIGS. 5(b), 5(c), and 5(e), when a clad material made up of the core 2a and brazing material 2b is used for the fins 211 and 212, the hairpin tubes 1 are brazed to the fins 211 and 212 by the brazing material 2b. When a bare material made up of only the core 2a is used for the fins 211 and 212 as with FIGS. 5(a) and 5(d) and the hairpin tubes 1 have a brazing material layer, the hairpin tubes 1 and fins 2 are brazed together by the brazing material of the hairpin tubes 1. When a bare material made up of only the core 2a is used for the fins 211 and 212 as with FIGS. 5(a) and 5(d) and the hairpin tubes 1 do not have a brazing material layer, the hairpin tubes 1 and the fins 2 are brazed together by being supplied with preplaced filler metal. The hairpin tubes 1 and the fins 2 are brazed together by furnace brazing performed in a high-temperature atmosphere furnace.

In the case of the flat-tube heat exchanger according to Embodiment 2, the material composition of the fins 2 is as described with reference to FIGS. 7(a) to 7(e) and a mode of brazing is similar to that of the flat-tube heat exchanger according to Embodiment 1 described above.

FIG. 17 is a diagram showing one step in production of the flat-tube heat exchanger. Plural heat exchanger cores are created in the manner described above and placed side by side to assemble a flat-tube heat exchanger. In the example shown in FIG. 17, two heat exchanger cores, namely the heat exchanger cores 11 and 12, are placed side by side. According to Embodiment 10, the heat exchanger cores 11 and 12 are placed side by side in the stage direction, i.e., in a direction crossing the direction of the notches in the fins 2 in which the hairpin tubes 1 are placed and at the same time in a direction extending along the planes of the fins 2. The step of placing the heat exchanger cores 11 and 12 side by side may be carried out before the hairpin tubes 1 and fins 2 are brazed together.

After the heat exchanger cores 11 and 12 are placed side by side in the stage direction, the brazing sheet 7 is inserted between the heat exchanger cores 11 and 12 to assemble the flat-tube heat exchanger 101. The assembly of the flat-tube heat exchanger 101 is carried out on a work bench or dolly. In inserting the brazing sheet 7, a jig may be used to adjust relative locations of the hairpin tubes 1, the fins 2, and brazing sheet 7 and fix these elements.

After the flat-tube heat exchanger is assembled, parts used to couple together cut ends of the hairpin tubes 1 are connected. Examples of the coupling parts include a U-bend used to connect a pair of heat transfer tubes, a header used to connect to individual heat transfer tubes from a main passage, and a distributor. In connecting the cut end of each hairpin tube 1 to a U-bend, a circular tube, a header, or a distributor, an element called a joint is used in some cases to convert a passage from a circular tube to a flat tube.

As the flat-tube heat exchanger 101 assembled in the manner described above is loaded into a high-temperature atmosphere furnace, the heat exchanger cores 11 and 12 are brazed together via the brazing sheet 7, thereby creating the flat-tube heat exchanger 101. If the flat-tube heat exchanger 101 is assembled before brazing of the hairpin tubes 1 and the fins 2, the hairpin tubes 1 and the fins 2 are brazed together when the heat exchanger cores 11 and 12 are brazed together.

In the case of the flat-tube heat exchanger according to Embodiment 1, the materials for the brazing sheet 7 are as described with reference to FIGS. 5(a) to 5(e). When the brazing material 7b is used for the brazing sheet 7 as with FIGS. 5(a) and 5(b), the brazing sheet 7 is melted after being loaded into a high-temperature atmosphere furnace, and thus the brazing sheet 7 does not form a single layer in the flat-tube heat exchanger 101. When a bare material made up of only the core 7a is used for the brazing sheet 7 as with FIG. 5(c), a brazing material is supplied from the brazing material 2b of the fins 2 after being loaded into the high-temperature atmosphere furnace. After brazing, the brazing sheet 7 forms a single layer in the flat-tube heat exchanger 101. When a clad material is used for the brazing sheet 7 as with FIGS. 5(d) and 5(e), the core 7a remains after being loaded into the high-temperature atmosphere furnace. Thus, after brazing, the brazing sheet 7 forms a single layer in the flat-tube heat exchanger 101.

In the case of the flat-tube heat exchanger according to Embodiment 2, the material composition of the brazing sheet 7 is as described with reference to FIGS. 7(a) to 7(e) and a mode of the brazing sheet 7 after brazing is similar to that of the flat-tube heat exchanger according to Embodiment 1 described above.

In the case of the flat-tube heat exchanger according to Embodiment 5, the brazing sheet 7 shown in FIG. 10 is made up of only a brazing material. Thus, the brazing sheet 7 is melted after being loaded into the high-temperature atmosphere furnace, and consequently the brazing sheet 7 does not form a single layer in the flat-tube heat exchanger 101.

The hairpin tubes 1 are joined to the U-bends, a header, a distributor, and joints by being loaded into the high-temperature atmosphere furnace.

FIG. 18 is a diagram showing one step in production of the flat-tube heat exchanger. The flat-tube heat exchanger may be assembled by stacking plural structures each including the heat exchanger core 11, the heat exchanger core 12, and the brazing sheet 7 placed side by side in the stage direction as shown in FIG. 18. The structures are stacked along a column direction parallel to the direction of the planes of the fins 2 and crossing the stage direction at right angles.

In a first column, the heat exchanger cores 11 and 12 are placed side by side in the stage direction and the brazing sheet 7 is inserted between the heat exchanger cores 11 and 12. In a second column, similarly the heat exchanger cores 11 and 12 are placed side by side in the stage direction and the brazing sheet 7 is inserted between the heat exchanger cores 11 and 12. This creates a two-column structure. Then, the structure is loaded into the high-temperature atmosphere furnace. To prevent the heat exchanger cores in the first column and the heat exchanger cores in the second column from being joined together, an anti-joining sheet 30 for use to prevent joining is inserted between the two columns. When the flat-tube heat exchanger is produced by furnace brazing, carbon fiber is used for the joining prevention sheet, for example.

In loading the two-column structure into the high-temperature atmosphere furnace, a jig may be used to adjust and fix the relative locations of the hairpin tubes 1, the fins 2, and the brazing sheet 7.

Note that the parts used to connect the cut ends of the hairpin tubes 1 with each other may be brazed by furnace brazing when the heat exchanger cores are brazed together, brazed by burner brazing configured to burn a base material and the brazing material by flames, or brazed by high-frequency brazing.

As described above, according to Embodiment 10, production of the flat-tube heat exchanger includes placing the heat exchanger cores 11 and 12 side by side in the stage direction, i.e., a direction crossing the direction of the notches in the fins and at the same time a direction extending along the planes of the fins; and joining together the heat exchanger cores placed side by side. This keeps relative locations of the adjacent heat exchanger cores from shifting in the production of the flat-tube heat exchanger.

REFERENCE SIGNS LIST

1 hairpin tube 2 fin 2a core 2b brazing material 3 fin assembly 4 coupling element 5 header 6 distributor 7 brazing sheet 7a core 7b brazing material 8 fin collar 9 spacer block 10 heat exchanger core 11 heat exchanger core 12 heat exchanger core 15 flat tube 20 sheet material 30 anti-joining sheet 51 upper front panel 52 lower front panel 53 left side panel 54 fan guard 55 air outlet 56 base panel 57 compressor 58 accumulator 59 air inlet 100 flat-tube heat exchanger 101 flat-tube heat exchanger 107 flat-tube heat exchanger 108 flat-tube heat exchanger 109 flat-tube heat exchanger 111 heat exchanger core

• • 112 heat exchanger core 122 heat exchanger core 200 outdoor unit 211 fin 212 fin 221 fin 222 fin 231 fin 232 fin
  • 241 fin 242 fin 251 fin 252 fin 261 fin 262 fin
  • 271 fin 272 fin 281 heat exchanger core 282 heat exchanger core 291 heat exchanger core 292 heat exchanger core 311 heat exchanger core 312 heat exchanger core 411 heat exchanger core
  • 412 heat exchanger core 511 heat exchanger core 512 heat exchanger core 611 heat exchanger core 612 heat exchanger core
  • 711 heat exchanger core 712 heat exchanger core

Claims

1. A heat exchanger comprising a plurality of heat exchanger cores, each of the plurality of heat exchanger cores including a plurality of tabular fins with notches formed therein and a plurality of heat transfer tubes, wherein:

the fins are disposed such that planes of the fins face each other and the heat transfer tubes are placed in the notches in the fins so as to extend in a direction crossing the planes of the fins; and

the plurality of heat exchanger cores are placed side by side in a direction crossing a direction in which the notches are arranged along the fins and extending along the planes of the fins, and adjacent ones of the heat exchanger cores are brazed together.

2. (canceled)

3. The heat exchanger of claim 1, further comprising a brazing sheet placed between the adjacent ones of the heat exchanger cores, wherein the adjacent ones of the heat exchanger cores are brazed together by the brazing sheet.

4. The heat exchanger of claim 3, wherein at least either of the fins or the brazing sheet includes a brazing material.

5. The heat exchanger of claim 1, wherein the fins include a core and the brazing material.

6. The heat exchanger of claim 1, wherein, in the fins in at least one of the adjacent ones of the heat exchanger cores, end faces of the fins facing of the an other of the adjacent ones of the heat exchanger cores are bent.

7. The heat exchanger of claim 1, wherein, in the fins in at least one of the adjacent ones of the heat exchanger cores, the heat transfer tubes are exposed on end faces facing an other of the adjacent ones of the heat exchanger cores.

8. The heat exchanger of claim 7, wherein a block element made of metal is disposed between the adjacent ones of the heat exchanger cores and the adjacent ones of the heat exchanger cores are joined together via the block element.

9. The heat exchanger of claim 1, wherein the plurality of heat transfer tubes are hairpin tubes each of which is bent in a U-shape, and in one of the hairpin tubes, one of a pair of straight-tube portions extending in a lateral direction of the heat exchanger is located on an end face, of one of the adjacent ones of the heat exchanger cores, facing an other of the heat exchanger cores and an other of the pair of straight-tube portions is located on an end face, of the other of the heat exchanger cores, facing the one of the heat exchanger cores.

10. The heat exchanger of claim 1, wherein the plurality of heat transfer tubes are coupled together at one end by a header and coupled together at an other end by another header.

11. An air-conditioning apparatus equipped with the heat exchanger of claim 1.

12. A method for producing a heat exchanger that comprises a plurality of heat exchanger cores, each of the plurality of heat exchanger cores including a plurality of tabular fins with notches formed therein and a plurality of heat transfer tubes, the method comprising:

forming the heat exchanger cores in which the fins are disposed such that planes of the fins are opposed to each other and that the heat transfer tubes are placed in the notches in the fins so as to extend in a direction crossing the planes of the fins;

placing the plurality of heat exchanger cores side by side in a direction crossing a direction in which the notches are arranged along the fins and extending along the planes of the notches; and

joining together adjacent ones of the heat exchanger cores by brazing.

13. (canceled)

14. The method of claim 12, wherein a brazing sheet is used for brazing.

15. The method of claim 14, wherein the brazing sheet is made up of only a brazing material.