Heat exchanger

Abstract

A joining plate (132) of this heat exchanger comprises: a joining surface (132A) that faces a tank header (140) and is partially joined to the flat plate portion (141) of the tank header; and a punching part (132B) that is formed between adjacent plate holes (130A) of the joining surfaces in the row direction in which a plurality of tubes (111) are arranged in a line, is recessed to the opposite side of the tank header from the joining surface in the vertical direction perpendicular to the joining surface, and is formed wider than the width of a refrigerant flow path (143) in the width direction perpendicular to the row direction and the vertical direction.

Description

heat exchanger CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-72305 filed on April 26, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a heat exchanger.

[0003] 2. Description of the Related Art A heat exchanger configured to allow a high-pressure refrigerant fluid to pass therethrough has been proposed in, for example, Patent Document 1.

[0004] European Patent Application Publication No. 1813903

[0005] Typically, a heat exchanger includes a plurality of tubes through which a high-pressure refrigerant flows, and a tank portion disposed at the ends of the plurality of tubes.

[0006] The tank section includes a tank header for flowing high-pressure refrigerant in the row direction of the plurality of tubes arranged in a row, and a joining plate that distributes the high-pressure refrigerant to each tube and is joined to the tank header.

[0007] The tank header has a flat portion joined to the joining surface of the joining plate by brazing, and a bulging portion that bulges from the flat portion to the opposite side of the joining plate and forms a refrigerant flow path. Generally, the bulging portion is formed by molding the flow path into a thick tank header material using an extruded material or the like, because it needs to be designed to withstand high pressures of high-pressure refrigerant.

[0008] However, the joint between the bulge of the tank head and the joint plate is where the corner formed by the inner wall surface of the bulge that forms the refrigerant flow path of the tank head and the flat plate of the bulge abuts against the joint plate. If the corner has a large rounded shape, the brazing material at the joint contacts only a portion of the rounded corner. As a result, in a cross section perpendicular to the joint surface and the column direction, the angle between the tangent of the brazing material that contacts the corner and the tangent of the brazing material that contacts the joint surface becomes less than 90°. In other words, the shape of the brazing material becomes wedge-shaped, significantly reducing pressure resistance.

[0009] One possible solution is to reduce the radius of the corners. However, this would incur costs when molding the extruded material. Another possible solution is to sink the tank header toward the joining plate so that the brazing filler metal covers the entire corner. In other words, it is possible to reduce the clearance between the flat portion of the tank header and the joining surface of the joining plate. However, this would cause the brazing filler metal to overflow from the gap between the tank header and the joining plate. This could result in the tubes being clogged by the brazing filler metal that has overflowed into the refrigerant flow path.

[0010] In view of the above, an object of the present disclosure is to provide a heat exchanger that can accommodate the rounded corners of the tank header and can suppress clogging of the tubes with brazing material.

[0011] According to one aspect of the present disclosure, a heat exchanger includes a plurality of tubes through which a refrigerant flows, and a tank portion disposed at an end of the plurality of tubes.

[0012] The tank section has a structure in which a plurality of plates, each having a plurality of plate holes into which a plurality of tubes are inserted, and a tank header, which is combined with the joining plate of the top layer of the stack of plates, are integrated by brazing.

[0013] The tank header has a flat plate portion joined to the joining plate, and a bulging portion that bulges from the flat plate portion to the opposite side of the joining plate and forms a refrigerant flow path that communicates with each of the multiple tubes through the plate holes.

[0014] The joining plate has a joining surface that faces the tank header and is joined to the flat portion of the tank header, and a recess that is formed between adjacent plate holes in the joining surface in the row direction in which the multiple tubes are arranged in a row, is recessed from the joining surface to the opposite side of the tank header in a direction perpendicular to the joining surface, and is formed wider than the width of the refrigerant flow path in the width direction perpendicular to the row direction and the vertical direction.

[0015] According to this, since the joining plate has a recessed portion formed therein that is wider than the refrigerant flow path, the corner formed by the inner wall surface of the bulge and the flat portion is located within the recessed portion. In other words, the corner does not abut against the joining plate. Therefore, the flat portion of the tank header is joined to the joining surface of the joining plate, so the accuracy of the rounded shape of the corner is not affected. Furthermore, even if the brazing material between the flat portion of the tank header and the joining surface of the joining plate overflows into the refrigerant flow path, the overflowed brazing material can be contained in the recessed portion. Therefore, the rounded shape of the corner of the tank header can be tolerated, and clogging of the tube by the brazing material can be prevented.

[0016] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a perspective view of a heat exchanger according to a first embodiment, Fig. 2 is a plan view of a joint surface of a joint plate constituting a tank section, Fig. 3 is a cross-sectional view of the vicinity of a tank header corresponding to cross section III-III in Fig. 2, Fig. 4 is an enlarged cross-sectional view of the vicinity of a corner of the tank header and a corner of the joint plate in Fig. 3, Fig. 5 is a cross-sectional view of a comparative example to the structure of Fig. 4, Fig. 6 is a cross-sectional view of a comparative example to the structure of Fig. 4, Fig. 7 is a plan view of the joint surface of a joint plate as another example of the first embodiment, Fig. 8 is a plan view of the joint surface of a joint plate as another example of the first embodiment, and Fig. 9 is a cross-sectional view of the vicinity of a tank header according to a second embodiment.

[0017] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicated explanations may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being combinable in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination.

[0018] (First embodiment) Hereinafter, a first embodiment will be described with reference to the drawings. A heat exchanger according to this embodiment is used, for example, in a vehicle air conditioner. The heat exchanger is an evaporator that constitutes a supercritical refrigeration cycle in which the high-pressure side pressure is equal to or higher than the critical pressure. The evaporator cools the conditioned air blown by a blower fan by heat exchange with a refrigerant that circulates in the refrigeration cycle and is decompressed by an expansion valve. The refrigerant may be, for example, carbon dioxide (CO ２ ) is used.

[0019] FIG. 1 is a perspective view showing a schematic configuration of a heat exchanger 100. As shown in FIG. 1, the heat exchanger 100 has, for example, a 2-2 turn structure, and includes two rows of core sections 110 and tank sections 120 located above and below each core section 110. The heat exchanger 100 is composed of multiple members made of aluminum or an aluminum alloy, which is lightweight and highly corrosion-resistant. These components are assembled together by fitting, crimping, jig fixing, or the like, and then brazed together with a brazing material.

[0020] The core portion 110 has tubes 111, fins 112, and side plates (inserts) 113. The tubes 111 have a flat cross-sectional shape. A refrigerant flows through the tubes 111. A plurality of the tubes 111 are arranged in a row. The direction in which the plurality of tubes 111 are arranged in a row is referred to as the row direction.

[0021] The fins 112 are formed into a corrugated shape using thin strip material. The tubes 111 and fins 112 are alternately stacked in the column direction. A pair of side plates 113 serving as reinforcing members are provided further outward from the outermost fin 112. The heat exchanger 100 has two core sections 110, which are arranged in series with respect to the air flow direction A.

[0022] A pair of tanks 120 that collect and distribute the refrigerant are connected to both ends of the tubes 111 in the extension direction. Two rows of refrigerant flow paths are formed in the tanks 120 corresponding to the two core portions 110. The upper tank 120 has an inlet 121 connected to one end of the leeward-side refrigerant flow path and allowing the refrigerant to flow in from the outside, and an outlet 122 connected to one end of the windward-side refrigerant flow path and allowing the refrigerant to flow out to the outside. The other ends of the two refrigerant flow paths are connected by a communication passage (not shown). The two rows of refrigerant flow paths in the upper tank 120 are each divided by a center partition plate 123 located in the center of the rows. Side partition plates 124 are provided at both ends of the two rows of refrigerant flow paths in the lower tank 120.

[0023] 2 is a plan view of the plurality of plates 130 that make up the tank section 120, viewed from the tank header 140 side toward the tube 111 side. FIG. 3 is a cross-sectional view of the vicinity of the tank header 140, corresponding to the cross section III-III in FIG.

[0024] 2 and 3, the tank portion 120 includes a plurality of plates 130 and a tank header 140. The tank portion 120 is disposed at the end of the plurality of tubes 111.

[0025] The plurality of plates 130 connect each tube 111 to the tank header 140. The plurality of plates 130 includes a plate header 131 to which the tube 111 is connected, and a joining plate 132 combined with the tank header 140.

[0026] In this embodiment, the tank section 120 has a plurality of plates 130, which include one plate header 131 and one joining plate 132. Note that one or more intermediate plates may be provided between the plate header 131 and the joining plate 132.

[0027] The plate header 131 is the plate farthest from the tank header 140. The joining plate 132 is the plate that is positioned closest to the tank header 140 among the multiple plates 130 stacked together.

[0028] 2, the tube 111 has a flat, elongated hexagonal cross section. A plurality of tube holes 111A for circulating the refrigerant are formed inside the tube 111. For example, there are 13 tube holes 111A.

[0029] A plurality of flat plate holes 130A are formed in the plate header 131 and the joining plate 132, and the plurality of tubes 111 are inserted through the plate holes 130A of the joining plate 132. The tip ends of the tubes 111 are inserted into the plate holes 130A of the joining plate 132.

[0030] The opening shape of the plate hole 130A formed in the plate header 131 roughly matches the outer peripheral shape of the tube 111. The plate hole 130A formed in the joining plate 132 is formed larger than the plate hole 130A of the plate header 131 in order to ensure a wide gap between the inner wall surface of the plate hole 130A and the outer wall surface of the tube 111.

[0031] In addition, for the plate arranged between the tank header 140 and the plate header 131, the plate hole 130A does not have to be penetrating, depending on the design of the path of the refrigerant flowing through the core portion 110 and the length of the tube 111.

[0032] 3, the joining plate 132 has a joining surface 132A and a cutout portion 132B. The joining surface 132A is a surface that faces the tank header 140. A part of the joining surface 132A is joined to the tank header 140.

[0033] The cutouts 132B are formed in the range between adjacent plate holes 130A on the joining surface 132A in the column direction. The cutouts 132B are recessed in a direction perpendicular to the joining surface 132A of the joining plate 132 toward the opposite side of the tank header 140 from the joining surface 132A. In this embodiment, the cutouts 132B penetrate the joining plate 132 in the vertical direction.

[0034] The cutouts 132B are formed with the maximum width in the column direction so as not to overlap with the plate holes 130A formed in the joining plates 132. As shown in Fig. 2, in this embodiment, when the cutouts 132B are viewed in the vertical direction, the planar shape of the cutouts 132B is rectangular.

[0035] The planar shape of the cutout 132B is not limited to a square. The planar shape of the cutout 132B may be any other shape, such as a polygon, a circle, an ellipse, or any other planar shape. Of course, regardless of the shape of the cutout 132B, it is sufficient that the cutout 132B is formed so that at least a portion of the width in the column direction is maximized.

[0036] 3, the tank header 140 has a flat plate portion 141 and a bulging portion 142. The flat plate portion 141 is joined to the joining plate 132. The bulging portion 142 bulges out from the flat plate portion 141 to the opposite side of the joining plate 132, and forms a refrigerant flow path 143 that communicates with each of the plurality of tubes 111 via the plate holes 130A.

[0037] A refrigerant flow path 143 is formed between the bulge 142 and the joining plate 132. The refrigerant flow path 143 communicates with each of the plurality of tubes 111 via the plate holes 130A. The refrigerant flow path 143 extends in the row direction. The width of the refrigerant flow path 143 in the width direction is narrower than the width of the plate holes 130A.

[0038] A crimping portion 144 is formed on the edge of the tank header 140 to temporarily fix the tank header 140 by sandwiching the joining plate 132 and the plate header 131. The tank portion 120 is integrated by brazing, with the tube 111 inserted into the joining plate 132 and the plate header 131 and the crimping portion 144 sandwiching the joining plate 132 and the plate header 131.

[0039] 3, the cutout 132B is formed wider than the width of the refrigerant flow path 143 in the width direction perpendicular to the column direction and the vertical direction. As a result, when a corner 145 formed by the inner wall surface 142A of the bulging portion 142 of the tank header 140 and the flat plate portion 141 is viewed vertically, the corner 145 of the tank header 140 is located within the range where the cutout 132B is formed. The width direction coincides with the thickness direction of the core portion 110.

[0040] The cutout portion 132B can be formed with high precision by press working or the like. That is, the corner 132D formed by the joining surface 132A of the joining plate 132 and the wall surface 132C constituting the cutout portion 132B can be formed at an angle of approximately 90°. The wall surface 132C is a surface extending in the vertical direction. The above is the overall configuration of the heat exchanger 100.

[0041] Next, we will explain the effect of forming the cutout portion 132B in the joining plate 132. Figure 4 is an enlarged cross-sectional view of the vicinity of the corner 145 of the tank header 140 and the corner 132D of the joining plate 132. As shown in Figure 4, the flat plate portion 141 of the tank header 140 and the joining surface 132A of the joining plate 132 are joined with brazing material 150 so as to provide a predetermined clearance CL.

[0042] Furthermore, a cutout 132B is formed in the joining plate 132, and the width of the cutout 132B in the width direction is wider than the refrigerant flow path 143 of the tank header 140. Here, the width of the refrigerant flow path 143 can be defined as, for example, from a boundary 146 between one corner 145 and the flat portion 141 on one side in the width direction to a boundary between the other corner 145 and the flat portion 141 on the other side in the width direction. This makes it possible to prevent the brazing material 150 from coming into contact with the corner 145 of the tank header 140.

[0043] That is, by forming the punched portion 132B in the joining plate 132, the corner 145 of the tank header 140 can be positioned within the range where the punched portion 132B is formed. In other words, the joining end portion between the tank header 140 and the joining plate 132 can be moved to a position away from the corner 145 of the tank header 140. That is, the position of the fillet 151 of the brazing material 150 can be moved to the position of the flat portion 141. Therefore, the corner 145 of the tank header 140 does not abut against the joining surface 132A of the joining plate 132 in the vertical direction. Therefore, the accuracy of the R-shape of the corner 145 of the tank header 140 does not affect the pressure resistance of the joint between the tank header 140 and the joining plate 132.

[0044] Therefore, the fillet 151, which is the joint end of the brazing filler metal 150, does not contact the corner 145 of the tank header 140, but contacts the flat portion 141 of the tank header 140 and the wall surface 132C of the punched portion 132B. As a result, the angle formed by the fillet 151 of the brazing filler metal 150 is 90°. The angle formed by the fillet 151 of the brazing filler metal 150 is the angle formed by a first tangent L1 of the end of the fillet 151 that contacts the flat portion 141 and a second tangent L2 of the end of the fillet 151 that contacts the wall surface 132C. When the angle formed by the fillet 151 is 90°, a joint shape that alleviates stress can be obtained.

[0045] 4, the tangent lines L1 and L2 are drawn at positions away from the fillet 151 of the brazing filler metal 150 to make them easier to see. The same applies to other figures in which the tangent lines L1 and L2 are shown.

[0046] In this embodiment, the cutouts 132B are formed with the maximum width in the column direction that does not overlap with the plate holes 130A, thereby minimizing the joining area in the column direction between the corners 145 of the tank header 140 and the joining surfaces 132A of the joining plates 132.

[0047] As a comparative example, FIGS. 5 and 6 show a case where the joining plate 132 does not have the cutout portion 132B.

[0048] 5 shows a case where the height of the fillet 151 in the vertical direction, based on the joining surface 132A of the joining plate 132, is greater than the sum of the clearance CL and the height of the corner 145. In other words, the fillet 151 covers the entire corner 145 of the tank header 140. In this case, the angle between the first tangent line L1 and the second tangent line L2 is 90°. However, a large amount of the brazing material 150 overflows from the gap between the tank header 140 and the joining plate 132, which may clog the tube 111.

[0049] 6 shows a case where the height of the fillet 151 in the vertical direction relative to the joining surface 132A of the joining plate 132 is smaller than the sum of the clearance CL and the height of the corner 145. In other words, the fillet 151 is recessed below the corner 145 of the tank header 140. In this case, the angle between the first tangent line L1 and the second tangent line L2 is less than 90°. This causes the brazing filler metal 150 to become wedge-shaped, which causes a sudden increase in stress concentration on the fillet 151.

[0050] 4, the recess 132B is formed in the joining plate 132, which improves robustness against the rounded corners 145 of the tank header 140. Furthermore, even if the brazing filler metal 150 between the flat plate portion 141 of the tank header 140 and the joining surface 132A of the joining plate 132 overflows into the refrigerant flow path 143, the overflowing brazing filler metal 150 can be poured into the recess 132B.

[0051] On the other hand, in the practical structure of the heat exchanger 100, the left-right dimensions in the width direction are finite. Therefore, the wider the recess 132B is made, with a width greater than the refrigerant flow path 143 of the tank header 140, the lower the ratio of the pressure-receiving length to the joint length. Here, as shown in FIG. 3 , the joint length corresponds to the widthwise length from the outer wall surface 132E on one side of the joint surface 132A of the joint plate 132 in the width direction to the wall surface 132C of the recess 132B. The pressure-receiving length corresponds to the widthwise length from the wall surface 132C of the recess 132B to the boundary 146 between the corner 145 and the flat plate portion 141 of the tank header 140.

[0052] The pressure-receiving length may be defined as the length in the width direction from the position of the wall surface 132C of the cutout portion 132B to the connection position between the inner wall surface 142A of the bulging portion 142 and the corner portion 145. In other words, the pressure-receiving length may be defined to include the width of the corner portion 145.

[0053] For example, the ratio of the joint length to the pressure-receiving length can be the same, i.e., joint length:pressure-receiving length = 1:1. This makes it possible to ensure the joint strength between the tank header 140 and the joint plate 132 while forming the punched portion 132B in the joint plate 132. It is preferable that joint length / pressure-receiving length > 1. In other words, the joint length is longer than the pressure-receiving length. This increases the joint strength.

[0054] The relationship between the joint length and the pressure-receiving length can be set symmetrically on one side and the other side in the width direction of the tank header 140, with the tank header 140 as the center. Of course, as long as the joint length can be ensured, the ratio of the joint length to the pressure-receiving length can be different on one side and the other side in the width direction with the tank header 140 as the center. For example, on one side in the width direction with the tank header 140 as the center, the joint length / pressure-receiving length may be greater than 1, and on the other side in the width direction, the joint length:pressure-receiving length may be 1:1.

[0055] Therefore, the structure of the heat exchanger 100 described above allows the rounded corners 145 of the tank header 140 to be tolerated, and also prevents the tubes 111 from being clogged with the brazing material 150 .

[0056] 7, the cutouts 132B do not have to be formed with the maximum width in the column direction between adjacent plate holes 130A on the joining surface 132A of the joining plate 132. Note that, at each location where the cutouts 132B are formed on the joining plate 132, the column direction widths of the cutouts 132B may all be the same or may be partially different.

[0057] 8, a plurality of cutouts 132B may be formed in the column direction. Note that the number of cutouts 132B may be the same or different at each location where the cutouts 132B are formed on the joining plate 132. The width of each cutout 132B in the column direction may be the same for all or may be different for some.

[0058] In this embodiment, the cutout portion 132B corresponds to the recessed portion.

[0059] Second Embodiment In this embodiment, differences from the first embodiment will be mainly described. As shown in Fig. 9, in this embodiment, a recess 132F is formed in a joining plate 132.

[0060] The recess 132F is a groove formed by recessing a part of the joining surface 132A of the joining plate 132 toward the plate header 131. The recess 132F can be formed by press working or the like. The bottom surface of the recess 132F does not have to be flat. For example, the bottom surface of the recess 132F may be curved.

[0061] In this way, it is sufficient that at least a part of the joining surface 132A of the joining plate 132 is recessed. In other words, the recess 132F does not have to penetrate the joining plate 132. This provides the same effects as in the first embodiment.

[0062] The present disclosure is not limited to the above-described embodiments, and various modifications can be made as follows within the scope of the present disclosure.

[0063] For example, the tank header 140 may be joined to the plate header 131. In this case, the plate header 131 corresponds to the joining plate 132.

[0064] In the above embodiment, the flat tube 111 having a flat long hexagonal cross section is exemplified, but the cross section of the tube 111 may have other shapes such as an oval shape or a flat parallelogram shape.

[0065] In the above embodiment, the multi-hole, flat tube 111 having thirteen tube holes 111A is used as an example, but the number of tube holes 111A may be other than thirteen, and a tube with a single hole may also be used.

[0066] In the above embodiment, the crimping portion 144 is provided on the tank header 140, but the crimping portion may be provided on the plate header 131 or the intermediate plate. Furthermore, the crimping portion may be provided by a separate crimping member.

[0067] In the above embodiment, an evaporator is used as an example of a heat exchanger, but the present invention can also be applied to other heat exchangers.

[0068] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A heat exchanger including a plurality of tubes (111) through which a refrigerant flows, and a tank section (120) arranged at the end of the plurality of tubes, wherein the tank section has a structure in which a plurality of plates (130) having a plurality of plate holes (130A) into which the plurality of tubes are respectively inserted, and a tank header (140) combined with a joining plate (132) of the top layer of the stack of the plurality of plates are integrated by brazing, the tank header has a flat plate section (141) joined to the joining plate, and a bulging section (142) that bulges from the flat plate section to the opposite side of the joining plate and forms a refrigerant flow path (143) that communicates with each of the plurality of tubes via the plate holes, and the joining plate has a joining surface (132A) that faces the tank header and is joined to the flat plate section of the tank header, a recess (132B, 132F) formed between adjacent plate holes on the joint surface in a column direction in which the plurality of tubes are arranged in a row, recessed from the joint surface to the opposite side of the tank header in a direction perpendicular to the joint surface, and formed wider than the width of the refrigerant flow path in a width direction perpendicular to the column direction and the vertical direction.

2. A heat exchanger according to claim 1, wherein the recess is a cutout (132B) that penetrates the joining plate in the vertical direction.

3. A heat exchanger according to claim 1 or 2, wherein the recesses are formed with the maximum width in the column direction that does not overlap with the plate holes.

4. A heat exchanger according to claim 1 or 2, wherein a plurality of said recesses are formed in said column direction.

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