Heat exchangers and methods for manufacturing them

Abstract

Heat exchanger (10) with: a plurality of heat transfer tubes (11) through which a heat medium flows, wherein the plurality of heat transfer tubes (11) provided are made of aluminium and are arranged side by side; a plurality of connecting tubes (12, 13) through which a heat medium flows, wherein the plurality of connecting tubes (12, 13) are made of aluminium and are soldered to the end sections of the plurality of heat transfer tubes (11); and a heat equalization device (21, 22) which is formed from a heat conductor and is arranged in such a way that it is at least partially in contact with at least two of the plurality of connecting tubes (12, 13) and can transfer heat between them, wherein the heat compensation device (21, 22) and the plurality of connecting tubes (12, 13) are soldered together, and a soldering material (41) that connects the plurality of heat transfer tubes (11) to the plurality of connecting tubes (12, 13) has a lower melting point than a soldering material (40) that connects the heat equalization device (21, 22) to the plurality of connecting tubes (12, 13).

Description

Cross-reference to related registrations

[0001] The present invention is based on the Japanese patent application JP 2015 - 150 574 A filed on 30 July 2015 and on the Japanese patent application JP 2016 - 24 232 A filed on 11 February 2016, the contents of which are hereby incorporated by reference. Technical field

[0002] The present invention relates to a heat exchanger in which a heat transfer tube and a connecting tube are soldered together, and to a method for manufacturing the heat exchanger. Background of the state of the art

[0003] Previously, transverse finned tube heat exchangers were constructed from a copper heat transfer tube, which was brazed section by section using a phosphorus-copper solder and a series torch or similar device. In recent years, to reduce material costs, an aluminum tube has been increasingly used for the heat transfer tube and brazed with an Al-Si solder. In the case of the aluminum tube, the melting points of the base metal and the solder are close to each other, making it difficult to perform brazing without melting the base material.

[0004] Furthermore, the connecting tubes are used in various shapes in transverse finned tube heat exchangers. Therefore, even if a transverse finned tube heat exchanger is heated uniformly, for example by a series burner, the temperature of a part being brazed will vary depending on its position, because the heat capacities of the respective connecting tubes differ, or because the effects of the burner flame on the respective connecting tubes vary.

[0005] If the aluminum heat exchanger is soldered using a series burner or similar, the soldering process may not be easily carried out due to temperature fluctuations.

[0006] Particularly when three or more rows of heat transfer tubes are arranged in one depth direction of the heat exchanger, the influence of the flame on the heat exchanger tube in a middle row is less than on the heat transfer tubes in the two side rows. Therefore, a significant temperature fluctuation occurs in the parts being brazed.

[0007] For this reason, patent document 1 proposes a method that uses a soldering material with a low melting point, such as Zn or Zn-Al.

[0008] In the prior art described in patent document 1, the solder material has a much lower electrical potential than the base material, and thus the solder material is preferentially corroded. Therefore, the soldered part must be coated. For example, a heat-shrinkable tube or a coating is used as the coating material. State-of-the-art documents, patent documents Patent document 1: JP 2015 - 78 789 A Patent document 2: US 4,995,453 A

[0009] US Patent 4,995,453 A discloses a heat exchanger with a plurality of side-by-side heat transfer tubes through which a working medium flows; a plurality of curved reversing tubes at the head of the heat exchanger as connecting tubes that link the heat transfer tubes; and a head support element that supports the reversing tubes. Summary

[0010] In the prior art of patent document 1, since the method for applying the coating to the soldered part as a coating material requires a step to remove a flux residue after the previous soldering, the number of steps can increase significantly in some cases.

[0011] Furthermore, the method for applying the heat-shrinkable tube as the coating material cannot be applied for coating the connecting tube after soldering in the case where a connecting tube in the shape of a bent U is used as the connecting tube, and the application of this method is limited.

[0012] In view of the points set out above, it is an object of the present invention to provide a heat exchanger with a high brazing quality between a heat transfer tube and a connecting tube, and a method for manufacturing the heat exchanger.

[0013] This problem is solved by a heat exchanger having the features of claim 1. A method for manufacturing the heat exchanger is described in claim 7. Advantageous embodiments are the subject of the dependent claims.

[0014] According to claim 1, if the heat transfer tubes (heat transfer pipes) and the connecting pipes are soldered by heating in a process for manufacturing the heat exchanger, since the respective connecting pipes transfer heat to each other through the heat equalization device, a temperature increase can be prevented from varying between the respective connecting pipes.

[0015] Because of this, the variation in heat transfer (heat conduction) from each connecting pipe to a joint can be reduced, allowing the soldering between the heat transfer pipe and the connecting pipe to be thermally balanced. Therefore, a heat exchanger with a high-quality solder joint between the heat transfer pipes and the connecting pipe can be used.

[0016] According to the method of claim 7, the same operational effects can be achieved in the invention as described in the first aspect. Brief description of the drawings Fig. Figure 1 shows a front view of a heat exchanger according to a first embodiment of the present invention. Fig. Figure 2 shows a perspective view of a heat exchanger according to the first embodiment. Fig. Figure 3 shows a partial cross-sectional view of a heat transfer pipe and a connecting pipe according to the first embodiment. Fig. Figure 4 shows a schematic top view of a heat exchanger according to the first embodiment. Fig. Figure 5 shows a front view of a section of the core section according to the first embodiment. Fig. Figure 6 shows a front view of a section of a connecting pipe assembly according to the first embodiment. Fig. Figure 7 shows a cross-sectional view along a line VII-VII from Fig. 4. Fig. Figure 8 shows a cross-sectional view along a line VIII-VIII from Fig. 4. Fig. Figure 9 shows a cross-sectional view along a line IX-IX from Fig. 4. Fig. Figure 10 shows a cross-sectional view of a section of a heat exchanger in a modification of the first embodiment. Fig. Figure 11 shows a section-like enlarged front view of a heat exchanger in a high-frequency induction heating process according to a second embodiment of the present invention. Fig. Figure 12 shows a section-like enlarged side view of the heat exchanger in the high-frequency induction heating process according to the second embodiment. Fig. Figure 13 shows an illustration of arrangement examples of a coil in the high-frequency induction heating process according to the second embodiment. Fig. Figure 14 shows a graphical representation of the temperature of a soldered part in a high-frequency induction heating process according to the second embodiment. Fig. Figure 15 shows a partial perspective view of a heat exchanger according to a third embodiment of the present invention. Fig. Figure 16 shows a section-like enlarged view of the heat exchanger in the high-frequency induction heating process according to the third embodiment. Fig. Figure 17 shows a section-like enlarged front view of a heat exchanger according to a fourth embodiment of the present invention. Fig. Figure 18 shows a section-like enlarged front view of a heat exchanger according to a fifth embodiment of the present invention. Fig. Figure 19 shows a section-like enlarged front view of a heat exchanger according to a sixth embodiment of the present invention. Fig. Figure 20 shows a section-like enlarged front view of a heat exchanger according to a seventh embodiment of the present invention. Fig. Figure 21 shows a section-like enlarged front view of a heat exchanger according to an eighth embodiment of the present invention. Fig. Figure 22 shows a section-like enlarged front view of a heat exchanger according to a ninth embodiment of the present invention. Fig. Figure 23 shows a partial cross-sectional view of a part of a heat exchanger before soldering the connecting tubes and the heat compensation element according to a modification of the present invention. Fig. Figure 24 shows a partial cross-sectional view of a part of a heat exchanger after soldering the connecting tubes and the heat compensation element according to a modification of the present invention. Fig. Figure 25 shows a partial cross-sectional view of a part of a heat exchanger before the soldering of the connecting tubes and the heat compensation element according to a modification of the present invention. Fig. Figure 26 shows a partial cross-sectional view of a part of a heat exchanger after soldering the connecting tubes and the heat compensation element according to a modification of the present invention. Fig. Figure 27 shows a partial cross-sectional view of a part of a heat exchanger before the soldering of the connecting tubes and the heat compensation element according to a modification of the present invention. Fig. Figure 28 shows a partial cross-sectional view of a part of a heat exchanger after soldering the connecting tubes and the heat compensation element according to a modification of the present invention. Fig. Figure 29 shows a partial cross-sectional view of a heat exchanger before the soldering of the connecting tubes and the heat transfer tubes according to a modification of the present invention. Fig. Figure 30 shows a partial cross-sectional view of a heat exchanger after soldering the connecting tubes and the heat transfer tubes according to a modification of the present invention. Fig. Figure 31 shows a partial cross-sectional view of a heat exchanger before the soldering of the connecting tubes and the heat transfer tubes according to a modification of the present invention. Fig. Figure 32 shows a partial cross-sectional view of a heat exchanger after soldering the connecting tubes and the heat transfer tubes according to a modification of the present invention. Fig. Figure 33 shows a partial cross-sectional view of a heat exchanger before the soldering of the connecting tubes, the heat compensation element and the heat transfer tubes according to a modification of the present invention. Fig. Figure 34 shows a partial cross-sectional view of a heat exchanger after soldering the connecting tubes, the heat compensation element and the heat transfer tubes according to a modification of the present invention. Description of the exemplary implementations

[0017] A multitude of embodiments of the present invention are described below with reference to the drawings. In the respective embodiments, a part corresponding to an item described in a previous embodiment may bear the same reference numeral, and a repeated explanation of this part may be omitted. If only a part of an assembly is described in one embodiment, another previous embodiment may be applied to the remaining parts of the assembly.

[0018] The parts can be combined even if it is not explicitly stated that the parts can be combined. The exemplary embodiments can also be combined in some cases even if it is not explicitly stated that the exemplary embodiments can be combined, provided that the combination is not problematic. 1. Example of implementation

[0019] Below is a heat exchanger 10 with reference to the Fig. 1 to 4 described, which is manufactured by soldering. The heat exchanger 10 is a coolant circuit heat exchanger for exchanging heat between a coolant in a coolant circuit and air.

[0020] In the drawings, an arrow W indicates the width direction of the heat exchanger 10. In the drawings, an arrow D indicates the depth direction of the heat exchanger 10. In the drawings, an arrow H indicates the height direction of the heat exchanger 10.

[0021] The heat exchanger 10 has a large number of heat transfer tubes (hereinafter referred to as heat transfer tubes) 11, a large number of connecting tubes 12, 13, a large number of fins 14 and side plates 17. The heat exchanger 10 is a transverse finned tube heat exchanger in which a large number of tubular heat transfer tubes (heat transfer tubes) 11 are inserted into a large number of plate-shaped fins 14.

[0022] Each of the heat transfer tubes 11 is a heat exchanger element that exchanges heat between a coolant flowing inside the heat transfer tube 11 and air flowing outside the heat transfer tube 11. The heat transfer tube 11 extends linearly in the vertical direction H of the heat exchanger 10. The numerous heat transfer tubes 11 are aligned side by side in the horizontal direction W of the heat exchanger 10. In other words, the orientation of the heat transfer tubes 11 coincides with the horizontal direction W of the heat exchanger 10.

[0023] The heat transfer tubes 11 are also arranged in a multitude of rows in the depth direction D of the heat exchanger 10. The air flowing outside the heat transfer tubes 11 flows in the depth direction D of the heat exchanger 10.

[0024] A large number of connecting pipes 12 and 13 are broadly divided into pipe connecting pipes 12 and tank connecting pipes 13. The pipe connecting pipes 12 each have a hairpin-shaped form and connect one end section of the two heat transfer pipes 11 to each other.

[0025] The tank connecting pipes 13 each have a shape that extends essentially linearly, and, as shown in Fig. As shown in Figure 2, they connect an end section of the corresponding heat transfer pipe 11 to a coolant tank 15. The coolant tank 15 is either a distribution tank that distributes the coolant to the many heat transfer pipes 11, or a collection tank into which the coolant from the many heat transfer pipes 11 is collected.

[0026] Most of the fins 14 are heat transfer support elements that increase the heat transfer surface area between the heat transfer tubes 11 and the air to facilitate heat exchange between the air and the coolant. The fins 14 are plate fins formed in a plate shape. The heat transfer tubes 11 and the fins 14 form a core section 18 for carrying out heat exchange between the coolant and the air.

[0027] Most of the fins 14 are stacked on top of each other in the vertical direction H of the heat exchanger 10 (in other words, the longitudinal direction of the heat transfer tubes 11). Most of the heat transfer tubes 11 penetrate the large number of fins 14 in a beveled manner. The heat transfer tubes 11 expand mechanically and come into close contact with the fins 14.

[0028] The heat transfer tubes 11 and the fins 14 form the core section 18 of the heat exchanger 10. The side plate 17 is a reinforcing element that strengthens the core section 18.

[0029] The heat transfer tubes 11, the connecting tubes 12, 13, the fins 14, and the side plates 17 are each made of an aluminum alloy. As the heat transfer tubes 11 expand, they are firmly connected to one another. The soldering material is heated and melted so that the heat transfer tubes 11 and the connecting tubes 12, 13 are soldered together.

[0030] As this is in Fig. As shown in Figure 3, an enlarged opening section 11a and a flared section 11b are formed at an end section of each heat transfer tube 11. The enlarged opening section 11a is formed by increasing the diameter of an end opening section of the heat transfer tube 11. The flared section 11b is formed by further flared the enlarged opening section 11a. An end piece of the connecting tubes 12 and 13 is inserted into the enlarged opening section 11a of the heat transfer tube 11. The insertion gaps between the heat transfer tube 11 and the connecting tubes 12 and 13 are soldered together to provide a coolant flow channel.

[0031] A large number of connections 16 between the heat transfer tubes 11 and the connecting tubes 12, 13 are aligned in the lateral direction W of the heat exchanger 10. The connections 16 are also aligned in numerous rows in the depth direction D of the heat exchanger 10. The positions of these connections 16 in the vertical direction H of the heat exchanger 10 are identical to each other.

[0032] As this is in Fig. As shown in Figure 4, the pipe connection 12 has a mixture of short connecting pipes 12A, which are arranged parallel to the width direction W of the heat exchanger 10, short connecting pipes 12B, which are arranged obliquely to the width direction W of the heat exchanger 10, and long connecting pipes 12C. The tank connection pipe 13 is an inlet and outlet pipe for the coolant.

[0033] The following describes a method for manufacturing the heat exchanger 10. First, through-holes (not shown), through which the heat transfer tubes 11 are inserted, are provided in each of the fins 14 and the side plates 17. After the respective fins 14 have been arranged at equal intervals, the heat transfer tubes 11 are inserted through the through-holes.

[0034] A tube enlargement process is then carried out to enlarge the heat transfer tubes 11. More precisely, a tube expander, which has a larger diameter than the inner diameter of the heat transfer tube 11, is inserted into the heat transfer tube 11, and the heat transfer tube 11 is mechanically expanded (expanded, i.e., widened) by the tube expander. The expansion of the heat transfer tubes 11 brings the fins 14 and the side plates 17 into close contact with the heat transfer tubes 11 for the purpose of connection. Subsequently, the enlarged opening section 11a and the widened section 11b are formed at each end section of the heat transfer tubes 11. As a result, as shown in Fig. As shown in Figure 5, the core section 18 of the heat exchanger 10 has been manufactured.

[0035] Furthermore, an assembly process is carried out to connect the heat compensation element 21 to the connecting pipes 12 and 13. For example, the connecting pipes 12, 13 and the heat compensation element 21 are soldered together using an Al-Si soldering material. The connecting pipes 12, 13 and the heat compensation element 21 can be fixed together by welding, riveting, or the like. As a result, as shown in Fig. Figure 6 shows the connecting pipe assembly manufactured, which has the connecting pipes 12, 13 and the heat compensation element 21.

[0036] A non-corrosive flux containing a cesium fluoride system and a soldering material close to a eutectic composition of a ternary Al-Cu-Si element or a soldering material of an Al-Cu-Si-Zn system in which Zn is added to the aforementioned component, are suitably applied to an area PA shown by wavy lines in the connecting tubes 12 and 13 in Fig. 3 applied as a layer, in other words in an area close to a connection target section 16 to be connected to the connecting tubes 12 and 13.

[0037] The Al-Cu-Si solder material has been formulated to have a solidus temperature of 510 °C and a liquidus temperature of approximately 540 °C, which is considerably lower than the Al-Si base solidus temperature of 577 °C. To enable soldering within the aforementioned temperature range, the flux has a low-temperature activity of 420 °C.

[0038] The heat equalization element 21 is a heat equalization device for compensating (equalizing) the soldering between the heat transfer tubes 11 and the connecting tubes 12, 13. The heat equalization element 21 is made of, for example, aluminum.

[0039] After the tube enlargement process and the assembly process, a heating and joining process is performed. In the heating and joining process, the connecting tubes 12 and 13 of the connecting tube assembly 12 are joined to the heat transfer tubes 11 of the core section 18 by heating. More precisely, as described in the Fig. 7, Fig. 8 and Fig. As shown in Figure 9, after the connecting pipes 12 and 13 have been temporarily connected to the heat transfer pipes 11, the connection target section 16 between the heat transfer pipe 11 and the connecting pipes 12, 13 is locally heated by the series burner 30. The series burner 30 heats the connection target section 16 from the outside of the heat exchanger 10 in the depth direction D.

[0040] As a result, the connection target section 16 between the heat transfer tube 11 and the connecting tubes 12, 13 is locally heated to approximately 550 °C. Therefore, the brazing material on the area P, which is indicated by the wavy lines in Fig. Figure 3 shows the area near the connection target section 16, in which the soldering material is applied to the connecting tubes 12 and 13. The soldering material is melted and flows into the insertion gap between the heat transfer tube 11 and the connecting tubes 12 and 13 through the expanded section 11b of the heat transfer tube 11. As a result, the heat transfer tube 11 and the connecting tubes 12 and 13 are soldered together.

[0041] In the present embodiment, since the shapes of the connecting tubes 12 and 13 differ from one another, their heat capacities also differ. For this reason, if the heat compensation element 21 is not provided, the temperature of each brazed part (in other words, the insertion section of the heat transfer tube 11 and the connecting tubes 12, 13) becomes non-uniform, resulting in solder flow defects and melting of the base material.

[0042] In this respect, in the present embodiment, since the heat compensation element 21 is provided, even if the shape and heat capacity of the connecting tubes 12 and 13 differ from each other, the temperature fluctuation of the brazed part can be considerably reduced by the heat transfer effects of the heat compensation element 21. Therefore, a large number of parts can be brazed by the series burner 30 without causing melting of the base material and insufficient melting of the brazing material.

[0043] In other words, since the respective connecting pipes 12 and 13 transfer heat to each other via the heat equalization element 21, fluctuations in the temperature rise between the connecting pipes 12 and 13 are reduced. For this reason, the soldering quality is improved, as the soldering between the heat transfer pipe 11 and the connecting pipes 12 and 13 is thermally balanced.

[0044] Furthermore, a soldering material with a low melting point close to the eutectic composition of the ternary Al-Cu-Si element, or a soldering material with a low melting point of an Al-Cu-Si-Zn system in which Zn is added to the aforementioned component, is used for soldering the connecting tubes 12, 13 and the heat transfer tube 11. Therefore, the difference in melting point between the aluminum base metal and the soldering material is increased, and the soldering process is facilitated.

[0045] By appropriately selecting the composition of the solder material, the natural potential difference between the solder material and the aluminum base material can be reduced. As a result, corrosion of the solder material can preferably be prevented.

[0046] Furthermore, the heat compensation element 21 and the connecting tubes 12, 13 are joined together using an Al-Si solder material with a high melting point. Therefore, if the connecting tubes 12, 13 and the heat transfer tube 11 are soldered with the solder material with a low melting point, secondary dissolution can be prevented.

[0047] In a Fig. In the modification shown in Figure 10, three or more rows of heat transfer tubes 11 are also arranged in the depth direction D of the heat exchanger 10. In this modification, the influence of the flame on the heat transfer tube 11 in the middle row in the depth direction D of the heat exchanger 10 is less than that on the heat transfer tubes 11 in the two side rows. However, due to the heat transfer effect through the heat equalization element 21 and the effect of increasing the soldering temperature range by using the Al-Cu-Si ternary element solder, all three or more rows are easily soldered simultaneously by the row burner.

[0048] In the present embodiment, a system of three Al-Cu-Si elements is used for brazing the connecting tubes 12, 13 and the heat transfer tube 11. However, if the difference in shape between the connecting tubes 12 and 13 is small, an Al-Si brazing material can be used.

[0049] In the present embodiment, the heat compensation element 21 is formed from a heat conductor and is arranged in such a way that it comes into heat-transferable contact with at least a part of at least two connecting tubes 12 and 13 of the many connecting tubes 12 and 13.

[0050] According to the above-described setup, if the heat transfer tubes 11 and the connecting tubes 12 and 13 are soldered by heating in a process for manufacturing the heat exchanger, since the respective connecting tubes 12 and 13 transfer heat to each other through the heat compensation element 21, a fluctuation of a temperature increase between the respective connecting tubes 12 and 13 can be prevented.

[0051] For this reason, since the fluctuation in heat transfer from each of the connecting pipes 12 and 13 to the connection 16 can be reduced, a brazed joint between the heat transfer pipe 11 and the connecting pipes 12 can be thermally compensated. Therefore, a heat exchanger can be provided that exhibits a high brazed joint quality between the heat transfer pipes 11 and the connecting pipes 12 and 13.

[0052] Even in the case of the heat exchanger, where three or more rows of heat transfer tubes 11 as in Fig. As shown in 10, the soldering between the heat transfer tube 11 and the connecting tubes 12, 13 is thermally balanced, thus enabling the achievement of a high soldering quality.

[0053] In the present embodiment, the heat compensation element 21 and the numerous connecting tubes 12, 13 are soldered together. The solder material that connects the numerous heat transfer tubes 11 and the numerous connecting tubes 12, 13 has a lower melting point than the solder material that connects the heat compensation element 21 and the numerous connecting tubes 12, 13.

[0054] This prevents the solder material that connects the heat transfer tube 11 and the many connecting tubes 12, 13 from dissolving secondarily when the connecting tubes 12, 13 and the heat transfer tube 11 are soldered.

[0055] In the present embodiment, the brazing material connecting the many heat transfer tubes 11 to the many connecting tubes 12, 13 can be an Al-Cu-Si or an Al-Cu-Si-Zn brazing material. According to the setup described above, since the melting point of the brazing material connecting the many heat transfer tubes 11 and the many connecting tubes 12, 13 is low, the melting point difference of the brazing material between the aluminum heat transfer tube 11 and the connecting tubes 12, 13 is increased. For this reason, brazing between the heat transfer tube 11 and the connecting tubes 12, 13 is facilitated.

[0056] In the present embodiment, the heat compensation element 21 and the numerous connecting tubes 12, 13 come into mechanical contact with each other. As a result, if the connecting tubes 12, 13 and the heat transfer tube 11 are soldered with the low-melting-point soldering material, the heat compensation element 21 and the numerous connecting tubes 12, 13 can be reliably brought into contact with each other to ensure reliable heat transfer.

[0057] In the present embodiment, the many heat transfer tubes 11 and the many connecting tubes 12, 13 are soldered together in a state in which the heat compensation element 21, which forms the heat conductor, is arranged such that it comes into heat-transferable contact at least partially with at least two tubes 12 and 13 of the many connecting tubes 12 and 13.

[0058] According to the above-described setup, if the heat transfer tubes 11 and the connecting tubes 12, 13 are soldered by heating in a process to manufacture the heat exchanger, since the respective connecting tubes 12 and 13 transfer heat to each other through the heat compensation element 21, fluctuations in temperature rise between the respective connecting tubes 12 and 13 can be prevented.

[0059] For this reason, the soldering between the heat transfer tube 11 and the connecting tubes 12, 13 can be thermally balanced, as the fluctuation in heat transfer from each of the connecting tubes 12 and 13 to the connection 16 can be reduced. Therefore, a heat exchanger can be provided that exhibits a high soldering quality between the heat transfer tubes and the connecting tubes.

[0060] In the present embodiment, the core section 18 is produced by connecting the fin 14 and the many heat transfer tubes 11 together, wherein the connecting tube assembly 19 is produced by connecting the heat compensation element 21 and the many connecting tubes 12, 13, and the heat transfer tubes 11 and the many connecting tubes 12, 13 are soldered together by connecting the core section 18 and the connecting tube assembly 19.

[0061] As a result, if the many heat transfer tubes 11 and the many connecting tubes 12, 13 are soldered together, the heat compensation element 21 can easily be brought into heat-transferring contact with the many connecting tubes 12 and 13. Second embodiment

[0062] In the embodiment described above, the connecting pipes 12 and 13 are connected to the heat transfer pipe 11 by heating with the burner, however, in the present embodiment, the connecting pipes 12 and 13 are connected to the heat transfer pipe 11 by high-frequency induction heating.

[0063] More precisely, similar to the embodiment described above, a tube enlargement process is carried out to form a core section 18 of a heat exchanger 10, and an assembly process is carried out to form the connecting tube assembly 19, and afterwards a high-frequency induction heating process is carried out.

[0064] In the high-frequency induction heating process, a connection target section 16 between the heat transfer tube 11 and the connecting tubes 12, 13 is locally heated by high-frequency induction heating. As a result, the heat transfer tube 11 and the connecting tubes 12, 13 are soldered together.

[0065] The details of the high-frequency induction heating process are described below. First, how this is described in the Fig. 11 and Fig. Figure 12 shows a coil 20 for high-frequency induction heating arranged on one side of the connection target section 16 and a heat compensation element 21 is arranged above the coil 20.

[0066] An example of the arrangement of coil 20 is shown in Fig. 13 shown. In an example of Fig. 13(a) the coil 20 is placed on both sides of each heat transfer tube 11 and between the heat transfer tubes 11 in a lateral direction W of the heat exchanger 10 (in a direction perpendicular to the plane of the paper of Fig. 13(a) is introduced.

[0067] As in the example of the Fig. 13(b) to 13(d) there can be a place where coil 20 in the example of Fig. 13(a) has not been introduced.

[0068] The thermal equalization element 21 is a thermal equalization device for compensating for soldering between the heat transfer tubes 11 and the connecting tubes 12, 13. The thermal equalization element 21 is a magnetic body that reduces the transmission of magnetic flux. The thermal equalization element 21 is a heat conduction element formed from a thermal conductor. The thermal equalization element 21 is, for example, made of aluminum.

[0069] The heat equalization element 21 is temporarily fixed between a section of the connecting tubes 12 and 13, which is furthest from the connection target section 16, and the coil 20 by soldering, welding, or a clamping device. The heat equalization element 21 can be provisionally fixed prior to the high-frequency induction heating process.

[0070] The heat compensation element 21 is a plate-shaped element that extends in the width direction W of the heat exchanger 10. A hole 21(a) is provided in the heat compensation element 21 through which the connecting pipes 12 and 13 pass. A circumferential section of the body 21(a) within the heat compensation element 21 comes into contact with the outer circumferential surfaces of the connecting pipes 12 and 13.

[0071] An electric current flows in the coil 20 in a state where the coil 20 and the heat compensation element 21 are arranged in the positions mentioned above. The resulting magnetic flux subjects the connection target section 16 to high-frequency induction heating, and the solder material is melted.

[0072] At this point, the fluctuation in the temperature rise caused by the magnetic flux can be reduced by the heat compensation element 21. The reason is described below.

[0073] During high-frequency induction heating, a section with a high magnetic flux density is heated to a significant degree. Therefore, if the heat compensation element 21 is not used, the overall temperature is determined according to the magnetic flux density and the heat capacity. The magnetic flux density is determined according to the distance between the position of the coil 20 and the pipe touched by the magnetic flux.

[0074] If the connecting tubes 12 and 13 have a different shape relative to each other, such as a height difference in the U-bend or a difference in the L-shaped bend section, or if the installation directions of the connecting tubes 12 and 13 are different relative to each other, the distances between the connecting tubes 12, 13 and the coil 20 are different from each other, even if the heat capacities of the connecting tubes 12 and 13 are identical relative to each other, resulting in a temperature fluctuation between the connecting tubes 12 and 13, and the temperature fluctuation between the soldered parts becomes high.

[0075] In light of the circumstances described above, in the present embodiment, the shielding effect of the heat-compensating element 21, which is a magnetic body, prevents the magnetic flux from passing through. For this reason, fluctuations in the temperature rise caused by the magnetic flux can be reduced, even if the shapes of the sections of the connecting tubes 12 and 13 located further away from the coil 20 than the heat-compensating element 21 differ from one another, provided that the shape of the section of the connecting tubes 12 and 13 located closer to the coil 20 than the heat-compensating element 21 and the position of the connecting tubes 12 and 13 relative to the coil 20 are uniform. Furthermore, since the respective connecting tubes 12 and 13 transfer heat to each other through the heat-compensating element 21, fluctuations in the temperature rise between the connecting tubes 12 and 13 are further reduced.For this reason, the soldering quality is further improved, as the soldering between the heat transfer tube 11 and the connecting tubes 12, 13 is thermally balanced even better.

[0076] This can be achieved by a dashed line with two points in Fig. As shown in Figure 14, in a comparative example where the heat compensation element 21 is not used, the temperature fluctuation in each of the connection target sections 16 is approximately 140 °C. On the other hand, as shown by a continuous line in Fig. Figure 14 shows that in the present embodiment, which uses the heat compensation element 21, the temperature fluctuation of the connection target sections 16 is approximately 45 °C, and the temperature fluctuation is reduced by approximately 100 °C compared to the comparison example.

[0077] In the present embodiment, the heat compensation element 21 is soldered to the connecting pipes 12 and 13 by high-frequency induction heating. In other words, in the present embodiment, the heat compensation element 21 is a component of the heat exchanger 10.

[0078] The heat compensation element 21 can be detached from the connecting pipes 12 and 13 after high-frequency induction heating. In other words, the heat compensation element 21 can be a clamping device used in the manufacturing process of the heat exchanger 10.

[0079] In the present embodiment, in a state where the coil 20 is arranged on the side of the connection target section 16 and the heat compensation elements 21 and 22 are arranged between the section of the connecting tubes 12 and 13 furthest away from the connection target section 16 and the coil 20, a current is caused to flow through the coil 20, whereby the heat transfer tube 11 and the connecting tubes 12, 13 are soldered to the connection target section 16 by high-frequency induction heating.

[0080] According to the setup described above, during high-frequency induction heating, the heat-compensating elements 21 and 22 prevent the magnetic flux from passing through, thus reducing the magnetic flux density of a section of the connecting elements 12 and 13 that is further away from the coil 20 than the heat-compensating element 21. This reduces the temperature rise of the connecting pipes 12 and 13. Therefore, even if the shapes of the connecting pipes 12 and 13 differ from each other, variations in the temperature rise between them can be prevented.

[0081] Therefore, since fluctuations in heat transfer (heat conduction) from the connecting pipes 12 and 13 to the respective connection target sections 16 can be reduced, the brazing between the heat transfer pipes 11 and the connecting pipes 12, 13 can be made more balanced. Furthermore, the brazing quality between the heat pipe 11 and the connecting pipes 12, 13 in the heat exchanger 10 can be improved.

[0082] In the present embodiment, the heat compensation elements 21 and 22 are brought into heat-transferring contact with at least a part of the connecting pipes 12 and 13.

[0083] As a result, since the respective connecting pipes 12 and 13 transfer heat to each other via the heat equalization element 21, fluctuations in the temperature rise between the connecting pipes 12 and 13 can be further reduced. For this reason, since the soldering between the heat transfer pipe 11 and the connecting pipes 12 and 13 can be thermally balanced even more effectively, the soldering quality between the heat transfer pipe 11 and the connecting pipes 12 and 13 can be further improved.

[0084] In the present embodiment, the heat compensation elements 21 and 22 are such elements that extend in the orientation direction W of the heat transfer tubes 11. As a result, a large number of connection target sections 16 can be soldered by high-frequency induction heating. 3. Example of implementation

[0085] In the embodiments described above, the heat compensation element 21 is a plate-shaped element that extends in the alignment direction W of the heat transfer pipes 11. However, in the present embodiment, as shown in the Fig. 15 and Fig. As shown in Figure 16, each of the heat compensation elements 22 is a block-shaped element that sits (is fitted) between heat pipes 11.

[0086] The thermal balancing element 22 is a magnetic body that concentrates a magnetic flux and reduces the transmission of the magnetic flux. The thermal balancing element 22, which is a magnetic flux transmission reduction element, is made of aluminum, for example.

[0087] The heat equalization element 22 is temporarily fixed between a section of the connecting tubes 12 and 13 furthest from a connection target section 16 and a coil 20 by soldering, welding, or a clamping device. The heat equalization element 21 can be provisionally fixed prior to the high-frequency induction heating process. An edge of the heat equalization element 22 comes into contact with the outer circumferential surfaces of the connecting tubes 12 and 13.

[0088] Even if the element that sits (is fitted) between the heat transfer tubes 11 is used as the heat compensation element 22 as in the present embodiment, the same operating effects can be achieved as in the embodiments described above. 4. Example of implementation

[0089] In the present embodiment, as is shown in Fig. As shown in Figure 17, an end section of a plate-shaped heat compensation element 21 is extended and bent in a direction opposite to a coil 20. As a result, since the magnetic flux concentration at the end section of the heat compensation element 21 can be reduced and the heat capacity of the end of the heat compensation element 21 can be increased, the thermal compensation of the soldered joint between the heat transfer tube 11 and the connecting tubes 12, 13 can be improved. 5. Example of implementation

[0090] In the present embodiment, as is shown in Fig. As shown in Figure 18, a plate-shaped heat compensation element 21 is not provided near the heat transfer tubes 11 at both end rows, but is only provided near a heat transfer tube 11 in a middle row.

[0091] Since, according to the setup described above, the heat equalization element 21, which is located near the heat transfer tube 11 in the middle row, is subjected to induction heating and generates heat, the temperature of the heat transfer tube 11 in the middle row, which has a low heat generation output, can be set to the same temperature as that of the heat transfer tubes 11 at both end rows, which have a high heat generation output. As a result, the thermal compensation of the solder joint between the heat transfer tube 11 and the connecting tubes 12, 13 can be improved. 6. Example of implementation

[0092] In the present embodiment, as shown in Fig. As shown in Figure 19, a plate-shaped heat compensation element 21 has a curved shape, and a central section of the heat compensation element 21 is arranged closer to the coil 20 than both side sections.

[0093] In the central section of the heat equalization element 21, the magnetic flux density is higher and the amount of heat generation is greater than in the two end sections, thereby increasing the amount of heat transferred to the heat transfer tube 11 in the central row, which has a lower heat generation value. As a result, since the heat transfer tubes 11 in the central row, which have a lower heat generation value, can be brought to a temperature approximately equal to that of the heat transfer tubes 11 in the two end rows, which have a higher heat generation value, the thermal balancing of the brazed heat transfer tubes 11 and the connecting tubes 12, 13 can be improved. 7. Example of implementation

[0094] In the present embodiment, as is shown in Fig. As shown in Figure 20, both ends of a side plate 17 are bent towards the connecting tubes 12 and 13. Since the assembly position of the side plate 17 varies due to a manufacturing defect or the like, the distance between a heat transfer tube 11 of the shortest row and a bent section of the side plate 17 also varies. If the distance between the heat transfer tube 11 of the shortest row and the bent section of the side plate 17 is long, the heat transfer tube 11 at the row furthest away has a high magnetic flux density and therefore reaches a high temperature.

[0095] Therefore, in the present embodiment, an end section of the heat compensation element 21 is bent between a curved position of the side plate 17 and the coil 20. As a result, since the bent section (bend section) of the heat compensation element 21 is subjected to induction heating, the influence of the side plate 17 can be eliminated, and a stable heat compensation property (a stable heat compensation capacity) can be achieved. 8. Example of implementation

[0096] In the present embodiment, the thicknesses of the heat transfer tubes 11 are different from each other. In an example from Fig. 21 the thickness of the two heat transfer tubes 11 on the right side is less than the thickness of the two heat transfer tubes 11 on the left side.

[0097] A plate-shaped heat compensation element 21 has a curved shape, and a section of the heat compensation element 21 on the side of the thin heat exchanger tube 11 is separated (spaced) from a coil 20 compared to a section on the side of the thick heat transfer tube 11.

[0098] The section of the heat equalization element 21 on the side of the thin heat exchanger tube 11 has a lower magnetic flux density and a lower heat generation amount than the side section of the thicker heat transfer tube 11. For this reason, since the temperature between the thin heat transfer tube 11, which has a lower heat capacity, and the thick heat transfer tube 11, which has a high heat capacity, can be made more uniform, the brazing between the heat transfer tube 11 and the connecting tubes 12, 13 can be even better balanced. 9. Example of implementation

[0099] In the present embodiment, the thicknesses of the heat transfer tubes 11 are different from each other. In an example from Fig. 22 the thickness of the two heat transfer tubes 11 on the right side is less than the thickness of the two heat transfer tubes 11 on the left side.

[0100] A section of the plate-shaped heat equalization element 21 on the side of the thin heat transfer tube 11 is folded back so that it is doubled. A section of the plate-shaped heat equalization element 21 on the side of the thick heat transfer tube 11 is not folded back so that it is single.

[0101] The heat capacity of a section of the heat equalization element 21 on the side of the thin heat transfer tube 11 is greater than that of a section on the side of the thick heat exchanger tube 11, to the extent that the amount of temperature rise is reduced. For this reason, since the temperature between the thin heat transfer tube 11, which has a low heat capacity, and the thick heat transfer tube 11, which has a high heat capacity, can be made more uniform, a soldered joint between the heat transfer tube 11 and the connecting tubes 12, 13 can be better compensated.

[0102] Even if the plate-shaped heat equalization elements 21 on the side of the thin heat transfer tube 11 are doubled and only one plate-shaped heat equalization element 21 is formed on the side of the thick heat transfer tube 11, the same operating effects as in the example of Fig. 22 will be achieved.

[0103] Even if the plate thickness of the plate-shaped heat equalization element 21 differs between the sections, and the plate thickness of a section of the plate-shaped heat equalization element 21 on the side of the thin heat transfer tube 11 is greater than the plate thickness of a section on the side of the thick heat transfer tube 11, the same operating effects as in the example from Fig. 22 will be achieved.

[0104] The aforementioned embodiments can be suitably combined with one another. For example, the aforementioned embodiments can be modified in the various ways described below. (1) In the second embodiment, the circumferential section of the hole 21a of the heat compensation element 21 comes into contact with the outer circumferential surfaces of the connecting pipes 12 and 13, but the circumferential section of the hole 21a can also be not in contact with the circumferential surface of the connecting pipes 12 and 13.

[0105] In this case, the temperature fluctuation of each of the connection target sections 16 is approximately 70 °C, and the temperature fluctuation is reduced by 70 °C compared to the comparison example that does not use the heat compensation element 21.

[0106] (2) In the embodiments described above, the heat exchanger 10 is a coolant circuit heat exchanger for exchanging heat between the coolant of the coolant circuit and the air; however, the heat exchanger 10 may comprise different heat exchangers that exchange heat between different heat media.

[0107] (3) In the first embodiment, the heat transfer pipe 11 and the connecting pipes 12, 13 are soldered by the series burner 30. In the second embodiment, the heat transfer pipe 11 and the connecting pipes 12, 13 are soldered by high-frequency induction heating. Alternatively, the heat transfer pipe 11 and the connecting pipes 12, 13 can be soldered by applying a heating process such as a plurality of burners, infrared heating, microwave heating, or the like.

[0108] In this case, when the heat-conducting elements, which are similar to the heat-equalizing elements 21 and 22 in the embodiment described above, are brought into contact with at least a portion of the connecting pipes 12 and 13, the connecting pipes 12 and 13 transfer heat to each other through the heat-equalizing element 21. As a result, the temperature fluctuation between the connecting pipes 12 and 13 can be reduced. Therefore, since the soldering between the heat transfer pipe 11 and the connecting pipes 12 and 13 can be thermally balanced, the soldering quality between the heat transfer pipe 11 and the connecting pipes 12 and 13 can be improved.

[0109] The heat transfer tube 11 and the connecting tubes 12, 13 can be joined together by flame brazing (torch brazing). In this case, if the same heat-conducting element as in the heat-equalizing elements 21 and 22 in the embodiments described above is brought into heat-transferring contact with at least a portion of the connecting tubes 12 and 13, a preheating effect is achieved. Therefore, the brazing can be carried out efficiently if the adjacent connections are brazed continuously.

[0110] In the embodiments described above, the connecting pipes 12, 13 and the heat compensation elements 21, 22 are soldered together. For example, as shown in Fig. As shown in Figure 23, the soldering material 40 is plated (applied) to the surfaces of the heat equalization elements 21, 22 before soldering. In this case, the soldering material 40, which is applied or plated to the surface of the heat equalization elements 21 and 22, is melted by heating and enters a space between the connecting tubes 12 and 13 and the heat equalization elements 21, 22. As shown in Fig. As shown in Figure 24, the connecting pipes 12, 13 and the heat compensation elements 21, 22 are soldered together.

[0111] Furthermore, as can be seen in Fig. As shown in Figure 25, a soldering material 40 with a ring-like shape (ring-shaped) is attached to each of the connecting tubes 12 and 13. In this case, the ring-shaped soldering material 40 is melted around each of the connecting tubes 12 and 13 by heating and enters a space between the connecting tubes 12, 13 and the heat equalization elements 21, 22. As shown in Fig. As shown in Figure 26, the connecting pipes 12, 13 and the heat compensation elements 21, 22 are soldered together.

[0112] Alternatively, as shown in Fig. As shown in Figure 27, a paste-like soldering material 40 is applied such that it comes into contact with the outer circumferential surfaces of the respective connecting tubes 12 and 13 and the surfaces of the heat equalization elements 21 and 22. In this case, the paste-like soldering material 40 is melted around each of the connecting tubes 12 and 13 by heating and enters a space between the connecting tubes 12, 13 and the heat equalization elements 21, 22. As shown in Fig. As shown in Figure 28, the connecting pipes 12, 13 and the heat compensation elements 21, 22 are soldered together.

[0113] In the embodiments described above, the heat transfer pipe 11 and the connecting pipes 12, 13 are soldered together. For example, as shown in Fig. As shown in Figure 29, a paste-like soldering material 41 is applied to the outer circumferential surfaces of the respective connecting tubes 12 and 13 before soldering. In this case, the soldering material 21 is melted by heating the outer circumferential surfaces of the respective connecting tubes 12 and 13 and enters a space between the heat transfer tubes 11 and the respective connecting tubes 12 and 13. As shown in Figure 29, a paste-like soldering material 41 is applied to the outer circumferential surfaces of the respective connecting tubes 12 and 13 before soldering. Fig. As shown in Figure 30, the heat transfer pipe 11 and the connecting pipes 12, 13 are soldered together.

[0114] Furthermore, as can be seen in Fig. As shown in Figure 31, the soldering material 31, in a ring-like shape (ring-shaped), is applied to each of the connecting tubes 12 and 13 before soldering. In this case, the ring-shaped soldering material 41 is melted around the respective connecting tubes 12 and 13 by heating and enters a space between the heat transfer tubes 11 and the respective connecting tubes 12 and 13. As shown in Figure 31, the soldering material 31 is applied to each of the connecting tubes 12 and 13 before soldering. Fig. As shown in Figure 32, the heat transfer pipe 11 and the connecting pipes 12, 13 are soldered together.

[0115] Furthermore, for example, as in Fig. Figure 33 shows that the soldering material 40, having a ring-like shape, can be applied above the heat equalization elements 21 and 22 of the connecting tubes 12 and 13, and the soldering material 41, also having a ring-like shape, can be applied above the upper ends of the heat transfer tubes 11 of the respective connecting tubes 12 and 13. In this case, the ring-shaped soldering materials 40 and 41 can be heated simultaneously around the respective connecting tubes 12 and 13. As shown in Fig.As shown in Figure 34, the heat transfer tube 11, the connecting tubes 12, 13, and the heat equalization elements 21, 22 can be soldered in one go. In this case, both soldering materials 40 and 41 can be the paste-like soldering material described above. While the present invention is described with reference to its exemplary embodiments, it should be understood that the invention is not limited to these exemplary embodiments and the illustrated configurations. On the contrary, the present invention is intended to cover various modifications and equivalent arrangements. Furthermore, while various elements in the different combinations and configurations shown are merely examples, other combinations and configurations with more, fewer, or only a single element also fall within the scope of the present invention.

Claims

[1] Heat exchanger (10) with: a plurality of heat transfer tubes (11) through which a heat medium flows, wherein the plurality of heat transfer tubes (11) provided are made of aluminium and are arranged side by side; a plurality of connecting tubes (12, 13) through which a heat medium flows, wherein the plurality of connecting tubes (12, 13) are made of aluminium and are soldered to the end sections of the plurality of heat transfer tubes (11); and a heat equalization device (21, 22) which is formed from a heat conductor and is arranged in such a way that it is at least partially in contact with at least two of the plurality of connecting tubes (12, 13) and can transfer heat between them, wherein the heat compensation device (21, 22) and the plurality of connecting tubes (12, 13) are soldered together, and a soldering material (41) that connects the plurality of heat transfer tubes (11) to the plurality of connecting tubes (12, 13) has a lower melting point than a soldering material (40) that connects the heat equalization device (21, 22) to the plurality of connecting tubes (12, 13). [2] Heat exchanger (10) according to claim 1, wherein the brazing material (41) connecting the plurality of heat transfer tubes (11) to the plurality of connecting tubes (12, 13) comprises either an Al-Cu-Si brazing material or an Al-Cu-Si-Zn brazing material. [3] Heat exchanger (10) according to one of claims 1 or 2, wherein the heat compensation device (21, 22) and the plurality of connecting tubes (12, 13) are in mechanical contact with each other. [4] Heat exchanger (10) according to any one of claims 1 to 3, wherein the plurality of heat transfer tubes (11) are arranged in three or more rows. [5] Heat exchanger (10) according to any one of claims 1 to 4, wherein at least two of the plurality of connecting tubes (12, 13) have a different shape to each other. [6] Heat exchanger (10) according to one of claims 1 to 5, which further comprises a side plate (17) which is connected to the plurality of connecting tubes (12, 13), wherein the brazing material (41) which connects the plurality of heat transfer tubes (11) to the plurality of connecting tubes (12, 13) is located between the side plate (17) and the heat equalization device (21, 22). [7] Method for manufacturing a heat exchanger (10) wherein the heat exchanger (10) comprises the following: a plurality of heat transfer tubes (11) through which a heat medium flows, wherein the plurality of heat transfer tubes (11) are made of aluminium and are arranged side by side; and a plurality of connecting pipes (12, 13) through which the heat medium flows, wherein the plurality of connecting pipes (12, 13) are made of aluminium and are connected to end sections of the plurality of heat transfer pipes (11), the method comprising the following: Soldering the plurality of heat transfer tubes (11) to the plurality of connecting tubes (12, 13) in a state in which a heat equalization device (21, 22) formed from a heat conductor is arranged such that it is in contact at least partially with at least two of the plurality of connecting tubes (12, 13) and can transfer heat between them, and in a state in which the heat equalization device (21, 22) and the plurality of connecting tubes (12, 13) are soldered together, wherein a soldering material (41) used for soldering the plurality of heat transfer tubes (11) to the plurality of connecting tubes (12, 13) has a lower melting point than a soldering material (40) connecting the heat equalization device (21, 22) to the plurality of connecting tubes (12, 13). [8] Method for manufacturing the heat exchanger (10) according to claim 7, further comprising the following steps: Producing a core section (18) by connecting the plurality of heat transfer tubes (11) and a fin (14) which facilitates heat exchange by increasing the heat transfer surface area; Manufacture of a connecting pipe assembly (19) by connecting the heat compensation device (21, 22) and the plurality of connecting pipes (12, 13); and Connecting the core section (18) and the connecting pipe assembly (19) before soldering the plurality of heat transfer pipes (11) to the plurality of connecting pipes (12, 13). [9] Method for manufacturing the heat exchanger (10) according to claim 7 or 8, further comprising the following step: Connecting the plurality of heat transfer tubes (11) with through holes provided on a side plate (17) prior to soldering the plurality of heat transfer tubes (11) to the plurality of connecting tubes (12, 13).

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