Heat exchanger

Abstract

To achieve space saving.SOLUTION: A heat exchanger includes: a pair of heat transfer pipes which serves as a flow passage for refrigerant flowing in the opposite directions with each other; and a header for connecting the pair of heat transfer pipes and for turning back the refrigerant from one heat transfer pipe to the other heat transfer pipe. The header includes: a first plate-like member for allowing the pair of heat transfer pipes to penetrate; a second plate-like member joined with the first plate-like member; and a space which is formed between the first plate-like member and the second plate-like member, and in which the refrigerant can flow from the one heat transfer pipe. A joint part comprising a joint surface between the first plate-like member and the second plate-like member has a folded part which is folded.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a heat exchanger.

Background Art

[0002] Generally, a heat exchanger is provided in an outdoor unit and an indoor unit of an air conditioner. The heat exchanger operates as an evaporator or a condenser by heat exchange between a refrigerant flowing inside a heat transfer tube and air flowing around fins arranged around the heat transfer tube.

[0003] Some heat exchangers have a plurality of rows of heat transfer tubes stacked in multiple stages with intervals, and the refrigerant reciprocates between the rows. Specifically, two refrigerant outlets and inlets are provided at one end of the heat exchanger. The refrigerant flowing in from one outlet and inlet flows through the heat transfer tubes of one row and reaches the other end of the heat exchanger, and may be folded back to the heat transfer tubes of another row by a return header connecting between the rows, and return to one end where the other outlet and inlet are provided. In this way, by reciprocating the refrigerant, the length of the refrigerant flow path becomes longer and a large amount of refrigerant can be sufficiently evaporated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, the return header that connects between rows of heat transfer tubes is generally formed by brazing two plates together. Specifically, two plates each having a peripheral portion in a flat plate shape and a recess formed in the central portion that is recessed from the surface of this flat plate shape are faced such that their recesses face each other, and the return header is formed by bonding them with the peripheral portion serving as the brazing margin. Since the two plates are joined with their recesses facing each other, a space is formed by the opposing recesses. Such a space is formed for each stage of the heat transfer tubes stacked in multiple stages, and a pair of heat transfer tubes located at the same stage in different rows are connected by one space.

[0006] That is, a pair of heat transfer tubes at the same stage that serve as flow paths for the refrigerant flowing in opposite directions are connected via one space formed by facing the recesses of the two plates. At the bottom of the recess of one of the plates forming this space, through holes are provided for inserting the tips of a pair of heat transfer tubes at the same stage in different rows. The refrigerant flowing out from one of the pair of heat transfer tubes flows into the other heat transfer tube via the space formed in the return header.

[0007] As described above, since the recess formed in the center of the plate forms the space of the return header, the peripheral portion of the plate around the recess is used as the brazing margin. In order to ensure the joining strength of the two plates and form the return header, it is necessary to increase the area of the brazing margin. However, when the area of the brazing margin is increased, there is a problem that the occupied space by the return header becomes large. That is, since the heat transfer tubes are connected to the space formed from the recess of the plate, when viewed from the direction in which the heat transfer tubes extend, the brazing margin of the plate spreads in a direction that does not overlap with the heat transfer tubes (a direction orthogonal to the direction in which the heat transfer tubes extend), making it difficult to save space.

[0008] The disclosed technology has been made in view of such points, and an object thereof is to provide a heat exchanger capable of saving space.

Means for Solving the Problems

[0009] In one aspect, the heat exchanger disclosed in the present application includes a pair of heat transfer tubes that serve as refrigerant flow paths flowing in opposite directions to each other, a plurality of fins installed at intervals on each of the pair of heat transfer tubes, and a header that connects the pair of heat transfer tubes and turns back the refrigerant from one heat transfer tube to the other heat transfer tube. The header includes a first plate-like member that penetrates the pair of heat transfer tubes, a second plate-like member joined to the first plate-like member, and a space formed between the first plate-like member and the second plate-like member into which the refrigerant can flow from the one heat transfer tube. The joint portion formed by the joint surface of the first plate-like member and the second plate-like member has a bent portion. The bent portion is formed at an end of the joint portion in the direction in which the pair of heat transfer tubes are arranged, Beyond the penetration surface located on the fin side closest to the header and through which the pair of heat transfer tubes penetrate, and has a length extending to the fin closest to the header.

Advantages of the Invention

[0010] According to one aspect of the heat exchanger disclosed in the present application, there is an effect that space can be saved.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0012] Hereinafter, an embodiment of the heat exchanger disclosed in the present application will be described in detail with reference to the drawings. Note that the present invention is not limited by this embodiment.

[0013] FIG. 1 is a perspective view showing the configuration of a heat exchanger 100 according to an embodiment. The heat exchanger 100 shown in FIG. 1 is provided, for example, in an outdoor unit of an air conditioner and operates as an evaporator or a condenser. The heat exchanger 100 has a heat exchange core portion 110, a first header 120, a first outlet / inlet 130, a second header 140, a second outlet / inlet 150, and a return header 170.

[0014] The heat exchange core portion 110 has an L shape in plan view and has two rows of heat transfer tubes stacked in multiple stages. The heat exchange core portion 110 also has a plurality of fins that guide air around the heat transfer tubes and promote heat exchange with the refrigerant flowing through the heat transfer tubes. Specifically, FIG. 2 is a view showing a cross section taken along line I-I of FIG. 1, and FIG. 3 is a view showing a cross section taken along line II-II of FIG. 1. In FIG. 1, detailed illustrations of the heat transfer tubes and fins included in the heat exchange core portion 110 are omitted.

[0015] As shown in FIG. 2, the heat exchange core portion 110 has a heat transfer tube 111a, a fin 112a, a heat transfer tube 111b, and a fin 112b. The heat exchange core portion 110 has a row in which the heat transfer tubes 111a are stacked in multiple stages with spaces therebetween and a row in which the heat transfer tubes 111b are stacked in multiple stages with spaces therebetween, and the heat transfer tubes 111a and 111b in the same stage of each row are arranged side by side so as to be close to each other and extend in parallel. The heat transfer tubes 111a and 111b are flat tubes having a flat cross section, and the heat transfer tubes 111a and 111b have the same cross-sectional shape. In the cross section of the heat transfer tubes 111a and 111b, a plurality of flow paths for the refrigerant are arranged in the longitudinal direction. The heat transfer tube 111a extends from the first header 120 to the return header 170, and the heat transfer tube 111b extends from the second header 140 to the return header 170.

[0016] The heat transfer tubes 111a and 111b penetrate through the comb-shaped fins 112a and 112b extending in the stacking direction of the heat transfer tubes 111a and 111b. That is, for example, as shown in FIG. 3, the heat transfer tube 111a penetrates through a plurality of fins 112a, and the refrigerant flowing inside the heat transfer tube 111a efficiently exchanges heat with the air passing between the plurality of fins 112a. Similarly, the heat transfer tube 111b penetrates through a plurality of fins 112b, and the refrigerant flowing inside the heat transfer tube 111b efficiently exchanges heat with the air passing between the plurality of fins 112b.

[0017] The fins 112a and 112b extend in the stacking direction of the heat transfer tubes 111a and 111b, and the heat transfer tubes 111a and 111b are inserted between the teeth of the comb shape. That is, the fin 112a allows a plurality of heat transfer tubes 111a arranged in a row in the stacking direction to pass through, and the fin 112b allows a plurality of heat transfer tubes 111b arranged in a row in the stacking direction to pass through. There is a gap between adjacent fins 112a in the direction in which the heat transfer tube 111a extends, and the space partitioned by the stacked heat transfer tubes 111a and the adjacent fins 112a serves as an air passage. Heat exchange occurs between the air passing through this passage and the refrigerant flowing inside the heat transfer tube 111a. Similarly, there is a gap between adjacent fins 112b in the direction in which the heat transfer tube 111b extends, and the space partitioned by the stacked heat transfer tubes 111b and the adjacent fins 112b serves as an air passage. Heat exchange occurs between the air passing through this passage and the refrigerant flowing inside the heat transfer tube 111b.

[0018] The first header 120 and the second header 140 are provided at one end of the heat exchanger 100. The first header 120 is connected to a plurality of heat transfer tubes 111a arranged in a row in the stacking direction, and the second header 140 is connected to a plurality of heat transfer tubes 111b arranged in a row in the stacking direction.

[0019] When the heat exchanger 100 functions as an evaporator, the first header 120 serves as the refrigerant inlet header and sends the refrigerant in a gas-liquid two-phase state flowing in from the first outflow / inflow port 130 to the heat transfer tubes 111a. Also, when the heat exchanger 100 functions as a condenser, the first header 120 serves as the refrigerant outlet header and sends the refrigerant in a gas-liquid two-phase state flowing in from the heat transfer tubes 111a to the first outflow / inflow port 130.

[0020] When the heat exchanger 100 functions as an evaporator, the second header 140 serves as the refrigerant outlet header and sends the refrigerant in a gas-liquid two-phase state flowing in from the heat transfer tubes 111b to the second outflow / inflow port 150. Also, when the heat exchanger 100 functions as a condenser, the second header 140 serves as the refrigerant inlet header and sends the refrigerant in a gas-liquid two-phase state flowing in from the second outflow / inflow port 150 to the heat transfer tubes 111b.

[0021] The return header 170 is provided at an end opposite to the end where the first header 120 and the second header 140 of the heat exchanger 100 are provided, and connects the heat transfer tubes 111a and 111b. That is, the return header 170 has a space where the tips of a pair of heat transfer tubes 111a and 111b in the same stage are commonly connected, turns back and allows the refrigerant flowing out from the tip of the heat transfer tube 111a to flow into the heat transfer tube 111b, and turns back and allows the refrigerant flowing out from the tip of the heat transfer tube 111b to flow into the heat transfer tube 111a.

[0022] FIG. 4 is a diagram showing the structure of the return header 170. FIG. 4 is a perspective view of the return header 170 as viewed from the side of the heat transfer tubes 111a and 111b (i.e., the inside of the heat exchanger 100).

[0023] The folded header 170 is formed by joining two plate-like members 171 and 172, for example, by brazing. An end portion 171a of the plate-like member 171 in the column width direction (hereinafter simply referred to as the "column width direction"), which is the direction in which a pair of heat transfer tubes 111a and 111b in the same row are arranged, is bent toward the heat transfer tubes 111a and 111b. An end portion 172a of the plate-like member 172 in the column width direction is also bent toward the heat transfer tubes 111a and 111b. And the joint portion between the end portion 171a of the plate-like member 171 and the end portion 172a of the plate-like member 172 forms a bent portion 170a of the folded header 170. That is, both ends in the column width direction of the joint portion of the two plate-like members 171 and 172 are bent portions 170a bent toward the plate-like member 172 side. For example, the plate-like member 171 corresponds to the "second plate-like member" in the claims, and the plate-like member 172 corresponds to the "first plate-like member" in the claims.

[0024] At the center of the plate-like member 171, recesses 171b for each row of the heat transfer tubes 111a and 111b are formed, and at the center of the plate-like member 172, recesses 172b for each row of the heat transfer tubes 111a and 111b are formed. The plate-like members 171 and 172 face each other such that the recesses 171b and 172b corresponding to the same row of the heat transfer tubes 111a and 111b face each other, and are joined so that a space is formed by the opposing recesses 171b and 172b. The brazing material for joining the plate-like members 171 and 172 is included, for example, in a clad layer formed on the surface of the plate-like member 172. When this clad layer is heated, the brazing material melts to join the plate-like member 171 and the plate-like member 172. The tips of the heat transfer tubes 111a and 111b penetrate the bottom of the recess 172b, and the space formed by the recesses 171b and 172b connects the heat transfer tube 111a and the heat transfer tube 111b. That is, the refrigerant can be folded back between the heat transfer tubes 111a and 111b through the space formed by the recesses 171b and 172b.

[0025] The portions of the plate-like members 171 and 172 excluding the recesses 171b and 172b serve as joint portions that are joined to the opposing plate-like members 172 and 171, for example, by brazing. That is, the portion of the plate-like member 171 excluding the recess 171b serves as a joint portion that is joined to the plate-like member 172, for example, by brazing, and the portion of the plate-like member 172 excluding the recess 172b serves as a joint portion that is joined to the plate-like member 171, for example, by brazing. In order to ensure the joint strength of the plate-like members 171 and 172, each joint portion of the plate-like members 171 and 172 has an area of a certain degree or more. That is, for example, the folded header 170 shown in FIG. 4 has joint portions with a relatively large area on the sides of the recesses 171b and 172b.

[0026] And, as described above, the end portions 171a and 172a in the column width direction of the joint portion serve as the bent portions 170a of the folded header 170. The bent portion 170a is bent so as to be substantially parallel to the direction in which the heat transfer tubes 111a and 111b extending through the bottom of the recess 172b extend. In other words, the bent portion 170a is bent at a substantially right angle with respect to the joint portion around the recesses 171b and 172b.

[0027] In this way, even when the area of the joint portion of the plate-like members 171 and 172 is increased to ensure the joint strength by forming the bent portion 170a, the size of the folded header 170 in the column width direction can be reduced. As a result, the occupied space by the folded header 170 can be reduced, and space saving can be achieved.

[0028] FIG. 5 is a diagram showing a cross section of the folded header 170 by a plane perpendicular to the stacking direction (hereinafter simply referred to as the "stacking direction") of the heat transfer tubes 111a and 111b.

[0029] As shown in FIG. 5, the plate-like members 171 and 172 are joined such that the bottoms of the recesses 171b of the plate-like member 171 and the recesses 172b of the plate-like member 172 face each other, thereby forming a space 170b for connecting the heat transfer tubes 111a and 111b. The tips of the heat transfer tubes 111a and 111b penetrate the bottom of the recess 172b and reach the space 170b. Thus, the heat transfer tubes 111a and 111b are connected by the space 170b.

[0030] The portions excluding the recesses 171b and 172b serve as a joint for joining the plate-like members 171 and 172 by, for example, brazing. Both ends in the column width direction of the joint portion are bent portions 170a bent in a direction substantially parallel to the direction in which the heat transfer tubes 111a and 111b extend. That is, the end portion 171a in the column width direction of the plate-like member 171 is bent toward the heat transfer tubes 111a and 111b, and the end portion 172a in the column width direction of the plate-like member 172 is bent toward the heat transfer tubes 111a and 111b, and these end portions 171a and 172a are joined to form the bent portion 170a.

[0031] The bent portion 170a is bent in a direction substantially parallel to the direction in which the heat transfer tubes 111a and 111b that penetrate the bottom of the recess 172b extend, and the tip of the bent portion 170a reaches the vicinity of the fins 112a and 112b closest to the folded header 170 beyond the bottom of the recess 172b. That is, the length of the bent portion 170a is longer than the depth of the recess 172b and is approximately equal to the distance between the folded header 170 and the fins 112a and 112b closest to the folded header 170.

[0032] By making the length of the bent portion 170a longer than the depth of the recess 172b, the ratio between the second moment of area in the recesses 171b and 172b of the plate-like members 171 and 172 and the second moment of area in the joint portion excluding the recesses 171b and 172b can be efficiently reduced. As a result, the concentration of stress on the joint portion can be alleviated, and deformation of the folded header 170 at the joint portion can be prevented.

[0033] Further, by making the length of the bent portion 170a approximately equal to the distance between the folded header 170 and the fins 112a and 112b closest to the folded header 170, the tip of the bent portion 170a reaches near the fins 112a and 112b, shielding the air passage between the folded header 170 and the fins 112a and 112b. As a result, the air around the heat exchanger 100 passes between the adjacent fins 112a and between the adjacent fins 112b without passing between the folded header 170 and the fins 112a and 112b, and the heat exchange efficiency can be improved.

[0034] As described above, according to the present embodiment, at the end in the column width direction of the folded header formed by joining two plate-like members, the joint of the two plate-like members is bent toward the side of the heat transfer tube. Thereby, while securing the area of the joint as the brazing cost of the plate-like member, the size in the column width direction of the folded header can be reduced. As a result, the occupied space by the folded header can be reduced, and space saving can be achieved.

[0035] In the above-described embodiment, the bent portions 170a are formed at both ends in the column width direction of the folded header 170. However, the bent portion may be formed only at one end in the column width direction. Further, a bent portion may be formed at the end in the stacking direction of the folded header 170. In short, by bending any end of the folded header 170 to form a bent portion, space saving is possible.

[0036] Also, in the above-described embodiment, the bent portion 170a is bent in a direction substantially parallel to the direction in which the heat transfer tubes 111a and 111b extend. However, the angle at which the bent portion 170a is bent may be arbitrary. However, by bending the bent portion 170a at an angle of 90 degrees or more, the size in the column width direction of the folded header 170 can be minimized. Further, by bending the bent portion 170a toward the plate-like member 172 side, the bent portion 170a does not protrude to the opposite side of the heat transfer tubes 111a and 111b. As a result, it is possible to prevent the heat exchanger 100 from increasing in size in the direction in which the heat transfer tubes 111a and 111b extend.

[0037] Furthermore, in the above-described embodiment, the heat transfer tubes 111a and 111b are connected by joining the plate-like members 171 and 172 with the concave portions 171b and 172b facing each other to form the space 170b. However, the structure of the folded header 170 is not limited to this. Specifically, for example, as shown in FIG. 6, a spacer 173 may be disposed between the plate-like members 171 and 172, and the plate-like members 171 and 172 sandwiching the spacer 173 may be joined to form the folded header 170. By sandwiching the spacer 173, a space 170b is formed between the plate-like members 171 and 172. The tips of the heat transfer tubes 111a and 111b penetrate the plate-like member 172 and reach the space 170b.

[0038] Also in the folded header 170 having such a structure, for example, the end portions 171a and 172a of the plate-like members 171 and 172 in the column width direction are bent toward the heat transfer tubes 111a and 111b side and joined to form the bent portion 170a. Thereby, even when the area of the joint portion of the plate-like members 171 and 172 is increased to ensure the joint strength, the size of the folded header 170 in the column width direction can be reduced, and space saving can be achieved.

Explanation of Reference Numerals

[0039] 110 Heat exchange core portion 111a, 111b Heat transfer tubes 112a, 112b Fins 120 First header 130 First outflow / inflow port 140 Second header 150 Second outflow / inflow port 170 Folded header 170a Bent portion 170b Space 171, 172 Plate-like members 171a, 172a End portions 171b, 172b Concave portions 173 Spacer

Claims

1. A heat exchanger having a pair of heat transfer tubes serving as flow paths for a refrigerant flowing in opposite directions to each other, a plurality of fins installed at intervals on each of the pair of heat transfer tubes, and a header connecting the pair of heat transfer tubes to turn back the refrigerant from one heat transfer tube to the other heat transfer tube, wherein the header has a first plate-like member penetrating through the pair of heat transfer tubes, a second plate-like member joined to the first plate-like member, and has a space formed between the first plate-like member and the second plate-like member and into which the refrigerant can flow from the one heat transfer tube, a joint portion formed by a joint surface of the first plate-like member and the second plate-like member has a bent portion, wherein the bent portion is formed at an end of the joint portion in a direction in which the pair of heat transfer tubes are arranged, is located on the fin side closest to the header, and has a length extending to the fin closest to the header beyond a through surface through which the pair of heat transfer tubes penetrate, characterized in that it is a heat exchanger.

2. The bent portion is bent toward the first plate-like member side. The heat exchanger according to claim 1, characterized in that.

3. The bent portion is bent in a direction parallel to the direction in which the pair of heat transfer tubes extending through the first plate-like member extend. The heat exchanger according to claim 1 or 2, characterized in that.

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