heat exchanger

Abstract

To provide a heat exchanger capable of suppressing the occurrence of brazing defects in the header tank of the heat exchanger. [Solution] The heat exchanger 1 comprises a header tank 3 having a cylindrical body 30 and a cap 33 that closes the opening at the end of the cylindrical body 30. The cylindrical body 30 is made up of a first member 31 and a second member 32, and includes a single-layer region 301 consisting only of the first member 31 or the second member 32, and a double-layer region 302 formed by overlapping the first member 31 and the second member 32. The cap 33 is made of a third member and has a bent portion BN at its edge 33T, which continuously covers the single-layer region 301 and the double-layer region 302 around the opening. An extension portion 35 is provided near the bent portion BN and towards the center of the cylindrical body 30 in the longitudinal direction from the bent portion BN, which is made up of at least one of the first member 31, the second member 32, and the third member.

Description

Technical Field

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

Background Art

[0002] Conventionally, in an air conditioner for a vehicle using a heat pump cycle, a plurality of heat exchangers are used in a refrigerant circuit. These plurality of heat exchangers include, for example, a heat exchanger disposed in an HVAC (Heating, Ventilating, and Air Conditioning) unit having an air flow passage through which air in the vehicle interior flows, and a heat exchanger (outdoor heat exchanger) disposed outside the vehicle. The outdoor heat exchanger has, for example, a plurality of tubes arranged in parallel and tanks connected to both ends (upper and lower ends) thereof, and some function as a radiator during cooling and as an absorber during heating.

[0003] The tanks of the outdoor heat exchanger are formed, for example, by facing a first tank member and a second tank member each formed in a substantially concave shape so as to close each other's openings, and joining a part of the side surface of the first tank member and a part of the side surface of the second tank member by overlapping them to form a cylindrical tank. Both ends of the cylindrical tank are closed with caps (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional heat exchanger, there has been a problem that poor brazing of the header tank is likely to occur during assembly.

[0006] Let's explain this in detail with reference to Figure 8. Figure 8 shows the brazing state during the assembly process of the heat exchanger 500, with Figure 8(A) being an overall front view, Figure 8(B) being an enlarged perspective view of the dashed rectangle in Figure 8(A), and Figure 8(C) being an enlarged view of the dashed rectangle in Figure 8(B).

[0007] When brazing the heat exchanger 500, especially large heat exchangers 500, they may be positioned in a predetermined orientation (brazing orientation) inside the furnace, as shown in Figure 8. In Figure 8, the upper part of the diagram is the upper part of the furnace, and the lower part is the lower part of the furnace.

[0008] The heat exchanger 500 consists of multiple tubes 501 arranged in the depth direction of Figure 8(A), with header tanks 503 and 504 connected to both ends of the tubes 501 in the longitudinal direction (left-right direction in Figure 8(A)). The header tanks 503 and 504 have a similar configuration and extend in the depth direction of Figure 8(A).

[0009] As shown in Figure 8(B), for example, the header tank 503 is constructed by combining two tank members (first tank member 531 and second tank member 532) that are roughly U-shaped in side view, with a portion of their sides overlapping to form a cylindrical body, and closing the openings at both ends with caps 533.

[0010] In this case, as shown in Figures 8(B) and 8(C), the cylindrical body has a single-layer region 503A consisting of only one of the first tank member 531 and the second tank member 532, and a double-layer region 503B where both members 531 and 532 overlap. In the example in Figure 8, the double-layer region 503B is the region where parts of the sides of both members 531 and 532 overlap, and the remaining region is the single-layer region 503A.

[0011] Furthermore, the cap 533 is, for example, a cover lid having an edge portion 534 that covers the perimeter of the opening, and the edge portion 534 is provided with a bent portion BN at a position corresponding to the stepped portion between the single-layer region 503A and the double-layer region 503B of the cylindrical body, so that they are continuously covered.

[0012] In this case, as shown in Figure 8(C), a boundary exists between the single-layer region 503A and the double-layer region 503B facing the outer bend radius R of the bent portion BN, and a roughly triangular prism-shaped gap G is created between them along the bend line of the bent portion BN. In particular, when the heat exchanger 500 is large, and the plate thickness of the tank members 531, 532 and the cap 533 is thick, the outer bend radius becomes larger, and as a result, the gap G also becomes larger.

[0013] Brazing material is applied to the inner surface of the cap 533 (lower side in Figure 8(C)) and the outer surfaces of the first tank member 531 and the second tank member 532 (upper side in Figure 8(C)). When brazing is performed, the material melts, filling the gap G, and fixing the first tank member 531, the second tank member 532, and the cap 533 together.

[0014] However, although one end of the roughly triangular prism-shaped gap G (the end corresponding to the bottom of the triangular prism) is covered by the cap 533, the other end is in communication with the outside. Therefore, when brazing is performed in the posture shown in Figure 8, it becomes difficult to control the flow of the molten brazing material near the upper bent portion BN. For example, it may flow along the outer surface of the first tank member 531 or into a narrower gap, resulting in a problem of poor brazing due to insufficient brazing material in and around the gap G.

[0015] This invention has been made in view of the above problems and provides a heat exchanger that can suppress the occurrence of brazing defects in the header tank of the heat exchanger. [Means for solving the problem]

[0016] The present invention relates to a heat exchanger having a header tank and a plurality of tubes, wherein the header tank each includes a halved first tank member and a second tank member, the first tank member has a pair of first sides extending in the longitudinal direction, the second tank member has a pair of second sides extending in the longitudinal direction and a bottom surface, the first tank member and the second tank member are facing each other such that at least a portion of the pair of first sides overlaps the inside of at least a portion of the pair of second sides, and in the region exposed to the outside of the second sides, at least a portion including the tip is provided with a thin-walled portion having a plate thickness less than the bottom surface. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a heat exchanger that can suppress the occurrence of brazing defects in the header tank of the heat exchanger. [Brief explanation of the drawing]

[0018] [Figure 1] This is an external perspective view of a heat exchanger according to an embodiment of the present invention. [Figure 2] This is a perspective view showing a first example of a header tank according to an embodiment of the present invention. [Figure 3] This figure shows a first example of a header tank according to an embodiment of the present invention, and is a cross-sectional view of the end. [Figure 4] This figure shows a first example of a header tank according to an embodiment of the present invention, (A) an exploded perspective view of the end, (B) a perspective view of the end, and (C) an enlarged perspective view. [Figure 5] This is a perspective view showing a second example of a header tank according to an embodiment of the present invention. [Figure 6] This figure shows a second example of a header tank according to an embodiment of the present invention, with (A) an exploded perspective view of the end, (B) a perspective view of the end, and (C) an enlarged perspective view. [Figure 7] This figure shows a third example of a header tank according to an embodiment of the present invention, with (A) an exploded perspective view of the end, (B) a front view of the end, and (C) an enlarged perspective view. [Figure 8] It is a diagram showing a conventional heat exchanger.

Mode for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIGS. 1 to 7 are examples of embodiments of the present invention. In the figures, parts with the same reference numerals indicate parts having the same function or the same components, and duplicate explanations in each figure are omitted as appropriate.

[0020] ​​​​​​​​​​​In the following explanation, the direction indicated by the arrow X in Figure 1 is referred to as the tube extension direction, the direction indicated by the arrow Y is referred to as the longitudinal direction of the header tank (or simply the longitudinal direction), and the direction indicated by the arrow Z is referred to as the short direction of the header tank (or simply the short direction).

[0023] Header tanks 3 and 4 are provided at both ends in the direction of tube extension (X direction). One of the header tanks, 3, is formed into a cylindrical shape by joining the first tank member 31 and the second tank member 32, and both ends in the longitudinal direction of the header tank (direction Y indicated by arrows in the figure) are sealed with caps 33, thereby creating a space inside through which a heat transfer medium flows.

[0024] The other header tank 4 is formed by joining the first tank member 41 and the second tank member 42 to form a cylindrical shape, and both ends in the longitudinal direction of the header tank (direction Y indicated by arrow) are sealed with caps 43, thereby creating a space inside through which a heat transfer medium flows.

[0025] In the example shown in Figure 1, the header tank 3 has an inlet 6 in the first tank member 31, and the second tank member 32 is connected to one end in the direction of tube extension (upper in Figure 1, Xa side). The header tank 4 has an outlet 7 in the first tank member 41, and the second tank member 42 is connected to the other end in the direction of tube extension (lower in Figure 1, Xb side).

[0026] In this configuration, the heat transfer medium flowing in from the inlet 6 flows through the upper header tank 3 to the tube 2, and the heat transfer medium flowing through the tube 2 flows through the lower header tank 4 and is discharged from the outlet 7.

[0027] Multiple tubes 2 are arranged longitudinally along the header tank, and a pair of side plates 5 are provided at both ends. The pair of side plates 5 define the spacing between the header tanks 3 and 4, and the multiple tubes 2 arranged inside them form a heat exchange core.

[0028] During brazing, the heat exchanger 1 is positioned in the furnace in the brazing position shown in Figure 8. Figure 8(A) is, for example, a view from arrow V in Figure 1. In this case, of the two sides S1 and S2 facing each other in the short direction (Z direction) of the header tanks 3 and 4 in Figure 1, one side (Za side) S1 is located on the upper side of the furnace.

[0029] Conventionally, there was a problem of insufficient brazing material occurring, particularly on the side S1 of the upper header tanks 3 and 4 in the furnace. However, in this embodiment, the insufficiency of brazing material is suppressed, enabling good brazing of the header tanks 3 and 4. The configurations of the header tanks 3 and 4 are the same below, so the header tank 3 will be described in detail as an example.

[0030] <First example> Figures 2 to 4 show the header tank 3 of the first example. Figure 2 is a perspective view showing the entire header tank 3, and Figure 3 is a cross-section of line XX in Figure 2, and an enlarged view of a part thereof (the dashed circle). Figure 4 is an enlarged view of the Ya side end in Figure 2. Note that the configuration of both ends in the longitudinal direction (Ya side and Yb side) of the header tank 3 is the same, and the configuration of both ends in the short direction (Za side and Zb side) is the same, so the Ya side end and the Za side end will be used as examples in the following explanation.

[0031] Referring to Figures 2 and 3, the header tank 3 has a cylindrical body 30 composed of a first tank member 31 and a second tank member 32, and caps 33 that close the openings at both ends of the cylindrical body 30 in the longitudinal direction. The first tank member 31 and the second tank member 32 are each half-shaped. As shown in the upper part of Figure 3, in this example, the first tank member 31 is formed in a substantially U-shape when viewed from the side, and has a bottom surface 31B and two first sides 31S that extend in the longitudinal direction of the header tank and are opposite to each other. In this example, the second tank member 32 is formed in a substantially U-shape when viewed from the side, and has a bottom surface 32B and two second sides 32S that extend in the longitudinal direction of the header tank and are opposite to each other.

[0032] The first tank member 31 and the second tank member 32 are combined such that they close each other's roughly concave openings. In this configuration, the first tank member 31 and the second tank member 32 are positioned such that at least a portion of the first side surface 31S of the first tank member 31 overlaps with at least a portion of the second side surface 32S of the second tank member 32, thereby forming a cylindrical body 30. In other words, the cylindrical body 30 is composed of a single-layer region 301 consisting only of the first tank member 31 or the second tank member 32, and a double-layer region 302 formed by overlapping the first tank member 31 or the second tank member 32. In the example shown in Figure 3, the region where the second side surface 32S of the second tank member 32 exists is the double-layer region 320, and the remaining region is the single-layer region 301.

[0033] The cap 33 is made of a metal member (cap member) similar to the first tank member 31 and the second tank member 32, and is a cover lid having an edge portion 33T, as shown in the exploded view on the Yb side of Figure 2. That is, the edge portion 33T continuously covers the single-layer region 301 and the double-layer region 302 around the end opening of the cylindrical body 30, as shown in Figure 3. For this reason, the edge portion 33T is provided with a bent portion BN to correspond to the step difference caused by the difference in plate thickness between the single-layer region 301 and the double-layer region 302.

[0034] In this configuration, as shown in the enlarged view in the lower part of Figure 3, a boundary exists between the single-layer region 301 and the double-layer region 302 facing the outer bend R portion of the bent portion BN, and a roughly triangular prism-shaped gap G is created between them, extending along the bend line BL of the bent portion BN (in the depth direction shown). One end of the gap G (the end corresponding to the bottom of the triangular prism) is covered by the cap 33, but the other end communicates with the outside at the tip of the edge 33T of the cap 33. In particular, when the heat exchanger 1 is large, the thickness of the first tank member 31, the second tank member 32 and the cap 33 is thick, which increases the outer bend R, and as a result the gap G also increases.

[0035] Brazing material is applied to the inner surface of the cap 33 (outer bend R side, the right side in the lower diagram of Figure 3) and the outer surfaces of the first tank member 31 and the second tank member 32 (the left side in the lower diagram of Figure 3). Conventionally, when a brazing position as shown in Figure 8 is adopted in the brazing process of assembly, the molten brazing material flows along the outer surface of the first tank member 31 or into a narrower gap in the upper bend BN, resulting in a problem of brazing defects due to insufficient brazing material in and around the gap G.

[0036] In this example, the outer surface of the second side 32S is partially thinned to create an inclined surface, thereby minimizing the outer bend radius of the bent portion BN as much as possible. However, a gap G is still unavoidable. In other words, even if the second side 32S were not thinned, a gap G would still occur, resulting in the same problem.

[0037] Therefore, in this embodiment, as shown in Figure 4, an extension 35 is provided near the bent portion BN and on the central side (Yb side in this example) in the longitudinal direction of the cylindrical body 30 (header tank longitudinal direction) than the bent portion BN (edge ​​portion 33T). The extension 35 is composed of at least one of the members of the first tank member 31, the second tank member 32, and the cap 33.

[0038] In the first example, the extension 35 (extension 35a) is made of the second tank member 32 and is provided adjacent to the bent portion BN. More specifically, the extension 35a made of the second tank member 32 is provided at a position where it at least overlaps with the imaginary line BL' (shown as a dashed line in Figure 4(C)), which is an extension of the bent portion BN shown by the large dashed line in the enlarged view of Figure 3 and Figure 4(C), in the longitudinal direction of the header tank, and is in contact with the tip surface 33Ts of the edge portion 33T of the cap 33. In this example, the second side surface 32S of the second tank member 32 that abuts the tip surface 33Ts of the edge portion 33T of the cap 33 is made to protrude more in the height direction (towards Xa) than other parts, and the extension 35a is provided at a position where it overlaps with the imaginary line BL'. In this way, the gap G can be covered by the extension 35a. In other words, the roughly triangular prism-shaped gap G is covered at one end (the end that forms the bottom of the triangular prism) by the cap 33, and at the other end by the extension 35a. The extension 35a abuts against the edge 33T of the cap 33 in the longitudinal direction of the header tank, and abuts against the first tank member 31 (first side surface 31S) in the short direction of the header tank, thereby restricting the outflow of molten brazing material within the gap G.

[0039] Therefore, even when brazing is performed in the brazing position shown in Figure 8, it is possible to suppress the leakage of molten brazing material from the gap G in the upper bent portion BN (gap G) and its vicinity, and prevent it from flowing downward. Furthermore, by sealing the end of the gap G with the extension portion 35a, the brazing material flows more easily into the gap G due to capillary action, making it possible to retain the brazing material in the gap G. In addition, since the extension portion 35a is made of the second tank member 32 to which the brazing material is applied, this also means that an additional amount of brazing material is added. The additional brazing material also flows more easily into the gap G, avoiding brazing defects between the cap 33 and the two-layer region 302 (first tank member 31 and second tank member 32), and enabling reliable brazing.

[0040] Furthermore, compared to simply adding brazing material (placing brazing) near the part of the gap G that communicates with the outside, by providing the extension 35a, the brazing material flows between the extension 35a and the first tank member 31, allowing it to be guided into the gap G without diffusion. It also makes it easier to form a layer of brazing material.

[0041] Note that the shape of the extension 35a is not limited to the shape shown in Figure 4; any shape that is positioned to overlap with the imaginary line BL' (a shape that can cover the gap G with the extension 35a) is acceptable.

[0042] <Second example> Figures 5 and 6 show the header tank 3 of the second example, where Figure 5 is a perspective view showing the entire header tank 3, and Figure 6 is an enlarged view of the Ya side end of Figure 5. The header tank 3 of the second example differs from the first example in the configuration of the extension 35. The extension 35 (extension 35b) of the second example is provided integrally with the bent portion BN (cap 33).

[0043] More specifically, referring to Figure 6, the extension 35b is made of the same material as the cap 33 and is provided adjacent to the bent portion BN. More specifically, the extension 35b made of the material of the cap 33 is provided at a position that at least overlaps with the imaginary line BL' (shown as a dashed line in Figure 6(C)), which is an extension of the bend line BL of the bent portion BN (shown as a dashed line in Figure 6(C)) in the longitudinal direction of the header tank. In this example, a part of the edge 33T of the cap 33 is made to protrude towards the center side (Yb side in this example) in the longitudinal direction of the header tank (towards the Yb side) along (to contact with) the upper end 32Su of the second side surface 32S, and the extension 35b is provided at a position that overlaps with the imaginary line BL'. In other words, the lower end 35bd of the extension 35b abuts against the upper end 32Su of the second side surface 32S. In this way, the extension 35b can cover the gap G, and the brazing material of the extension 35b can easily flow into the gap G via the upper end 32Su and the space between the extension 35b and the first side surface 31S.

[0044] Referring to Figure 6(A), in this example, a claw 331 is provided on the edge 33T of the cap 33 to temporarily fix the cap 33 to the first tank member 31. By bending this claw 331 toward the rib 316 provided on the first tank member 31, the cap 33 and the first tank member 31 are temporarily fixed together. The extension 35b is provided in the same shape as the claw 331, but it is not bent and instead abuts against the surface of the first tank member 31. The rest of the configuration is the same as in the first example.

[0045] Even in the second example, the gap G is covered by the extension 35b. The extension 35b abuts against the upper end 32Su of the second tank member 32 (second side surface 32S) in the height direction of the header tank, and abuts against the first tank member 31 (first side surface 31S) in the short direction of the header tank, thereby restricting the outflow of molten brazing material in the gap G. Furthermore, due to capillary action, the brazing material flows more easily into the gap G, making it possible to retain the brazing material in the gap G. In addition, since the extension 35b is made of the same material as the cap 33 to which the brazing material is applied, it also adds brazing material, thus avoiding brazing defects between the cap 33 and the two-layer region 302 (first tank member 31 and second tank member 32), and enabling reliable brazing.

[0046] In this case as well, compared to simply adding brazing material near the part of the gap G that communicates with the outside, providing the extension 35b allows the brazing material to flow between the extension 35b and the first tank member 31, thus guiding the brazing material into the gap G without diffusion. It also makes it easier to form a layer of brazing material.

[0047] Note that the shape of the extension 35b is not limited to the shape shown in Figure 6; any shape that is positioned to overlap with the imaginary line BL' (a shape that can cover the gap G with the extension 35b) is acceptable.

[0048] Alternatively, the extension portion 35b may be bent in the same way as the claw 331 and used for temporary fixing of the cap 33 and the first tank member 31.

[0049] <Third example> Figure 7 shows the header tank 3 of the third example, where Figure 7(A) is an exploded perspective view showing the Ya-side end of the header tank 3, Figure 7(B) is a front view showing the Ya-side end of the header tank 3, and Figure 7(C) is a perspective view.

[0050] In the third example, the header tank 3 has an extension 35 (extension 35c) that is integrally provided with the bent portion BN (cap 33), but its shape differs from that of the second example. In the second example, the extension 35b extends towards Yb, including a part of the bent portion BN of the cap 33, and a bent portion (extended bent portion 35bn) exists below the extension 35b. In other words, the lower end portion 35bd of the extension 35b is located below the bend line BL of the bent portion BN (see Figure 6).

[0051] In contrast, the extension 35c of the third example has a configuration in which the extension bent portion 35bn of the second example is removed. That is, the position of the lower end portion 35cd of the extension portion 35c is at the same position as the position of the bend line BL of the bend portion BN. As a result, the lower end portion 35cd of the extension portion 35c is in close proximity to the upper end portion 32Su of the second side surface 32S without contact. For example, the separation distance L of the proximity portion 37 between the lower end portion 35cd of the extension portion 35c and the upper end portion 32Su of the second side surface 32S is, for example, 0.5 mm or less, and preferably about 0.2 mm to 0.3 mm.

[0052] In the second example, processing the extension 35bn of the minute extension bend 35bn is time-consuming, but in the third example, processing the extension 35c becomes easier. Also, the brazing material of the extension 35c flows more easily into the gap G via the upper end portion 32Su, the space between the extension 35c and the first side surface 31S, the adjacent portion 37, etc. On the other hand, in this case, at least a part of the gap G is in communication with the outside. However, if the separation distance L of the adjacent portion 37 is, for example, 0.5 mm or less, the molten brazing material flows into the gap G via the adjacent portion 37 by capillary action, so that brazing defects can be avoided as in the first and second examples.

[0053] In this embodiment, the configuration of the header tank 3 was described as an example in which the first side surface 31S of the first tank member 31 overlaps the inside of the second side surface 32S of the second tank member 32. However, the configuration may also be such that the first side surface 31S of the first tank member 31 overlaps the outside of the second side surface 32S of the second tank member 32. In that case, for example, the extension 35a of the first example is made of the first tank member 31. Alternatively, for example, the first example may be combined with the second or third example.

[0054] It should be noted that the heat exchanger 1 of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0055] 1 heat exchanger 2 tubes 3, 4 Header Tanks 3,4 Header Tanks 5 Side Plates 6 Inlet 7 Outlet 30 Cylindrical body 31 First Tank Component 31B Bottom 31S first side 32 Second Tank Components 32B Bottom 32S second side 32Su upper end 33 caps 33T edge 35 Extension 35bd bottom end 37 Close-up section 301 One layer area 302 Two layer area BN bend section G Gap

Claims

1. A heat exchanger comprising a cylindrical body and a header tank having a cap that closes the opening at the end of the cylindrical body, The cylindrical body is formed by combining a first member and a second member, and includes a single-layer region consisting only of the first member or the second member, and a double-layer region in which the first member and the second member are stacked. The cap is made of a third member and has a bent portion at its edge to continuously cover the first layer region and the second layer region around the opening. An extension made of at least one of the first member, the second member, and the third member is provided near the bent portion and on the side of the cylindrical body toward the center in the longitudinal direction from the bent portion. A heat exchanger characterized by the following features.

2. The extension is a separate member from the third member and is provided adjacent to the bent portion. The heat exchanger according to feature 1.

3. The extension is provided integrally with the bent portion. The heat exchanger according to feature 1.

4. The extension covers the gap between the first member, the second member, and the bent portion. The heat exchanger according to feature 1.

5. The extension is provided in close proximity to the second member and not in contact with it. The heat exchanger according to feature 3.

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