WO2020189483A1 - Heat exchanger and heat exchanger manufacturing method - Google Patents

Abstract

A heat exchanger (1A) is provided with heat transfer tubes (20) and headers (10F, 10B). The heat transfer tubes (20) transfer heat to fins (30). Each of the headers (10F, 10B) has an outer wall (11F, 11B) having insertion holes into which the heat transfer tubes (20) are inserted and embossed portions (12) that surround the insertion holes and protrude in the tube axis direction of the heat transfer tubes (20). In the headers (10F, 10B), the heat transfer tubes (20) are brazed to the embossed portions (12) and the inner walls of the insertion holes.

Description

How to manufacture heat exchangers and heat exchangers

This disclosure relates to heat exchangers and methods for manufacturing heat exchangers.

Some heat exchangers have a header that distributes and aggregates the refrigerant to the heat transfer tube that transfers heat to the fins. In such heat exchangers, the header and heat transfer tube are generally brazed.

For example, Patent Document 1 includes a heat transfer tube, an insertion hole into which the heat transfer tube is inserted, and a header having an outer wall formed with a peripheral wall surrounding the opening of the insertion hole, and the heat transfer tube is brazed to the peripheral wall. The heat exchanger is disclosed.

In the heat exchanger described in Patent Document 1, the insertion hole and the peripheral wall are formed by burring the outer wall of the header.

On the other hand, Patent Document 2 describes that in a method of punching a metal plate to form a hole having a diameter smaller than the plate thickness on the metal plate, burrs adhere to the inner wall of the hole.

Japanese Unexamined Patent Publication No. 2000-39288 Japanese Unexamined Patent Publication No. 6-91334

In order to increase the joint strength between the heat transfer tube and the header, it is desirable to increase the joint area between the heat transfer tube and the header.

In the heat exchanger described in Patent Document 1, it is considered that the insertion hole and the peripheral wall are formed by burring in order to widen the joint area between the heat transfer tube and the header. Then, in forming the insertion hole and the peripheral wall, it is considered necessary to form a pilot hole smaller than the insertion hole in advance. However, as described in Patent Document 2, when the diameter of the pilot hole is smaller than the plate thickness, burrs adhere. Therefore, if the outer wall is too thick with respect to the insertion hole, it is difficult to form the insertion hole and the peripheral wall.

Also, in order to widen the joint area between the header and the heat transfer tube, it is conceivable to increase the thickness of the outer wall of the header. In this case as well, if the outer wall is too thick with respect to the insertion hole, it is difficult to form the insertion hole.

The present disclosure has been made in order to solve the above problems, and an object of the present disclosure is to provide a heat exchanger and a method for manufacturing a heat exchanger, which have a high joint strength between a heat transfer tube and a header and are easy to manufacture.

In order to achieve the above object, the heat exchanger according to the present disclosure surrounds the heat transfer tube for transferring heat to the fins, the insertion hole into which the heat transfer tube is inserted, and the insertion hole, and projects in the axial direction of the heat transfer tube. A header having an outer wall on which an embossed portion is formed is provided. In the header, heat transfer tubes are brazed to the embossed portion and the inner wall of the insertion hole.

According to the configuration of the present disclosure, the heat transfer tube is brazed to the embossed portion and the inner wall of the insertion hole, so that the joint strength is high. Further, since the embossed portion is only formed on the outer wall, it is easy to manufacture even if the thickness of the outer wall is increased.

Perspective view of the heat exchanger according to the first embodiment of the present disclosure. Perspective view of the heat transfer tube included in the heat exchanger according to the first embodiment of the present disclosure. Perspective view of the cut portion when the heat exchanger is cut in the region III shown in FIG. Front view of the cut portion when the heat exchanger is cut in the region III shown in FIG. Sectional view at the VV cutting line shown in FIG. Cross-sectional view of the outer wall of the header in which the embossed portion is formed by the method for manufacturing the heat exchanger according to the first embodiment of the present disclosure. Cross-sectional view of the outer wall of the header when a through hole is formed in the embossed portion in the method for manufacturing the heat exchanger according to the first embodiment of the present disclosure. Cross-sectional view of a header when a heat transfer tube is inserted into a through hole in the method for manufacturing a heat exchanger according to the first embodiment of the present disclosure. Perspective view of the heat exchanger according to the second embodiment of the present disclosure. Front view of the heat exchanger according to the second embodiment of the present disclosure. Cross-sectional view taken along the XI-XI cutting line shown in FIG. Cross-sectional view of the header when the heat transfer tube is inserted into the through hole in the method for manufacturing the heat exchanger according to the second embodiment of the present disclosure. Perspective view of the heat exchanger according to the third embodiment of the present disclosure. Front view of the heat exchanger according to the third embodiment of the present disclosure. Cross-sectional view taken along the XV-XV cutting line shown in FIG. Cross-sectional view of a modified example of the heat exchanger according to the first embodiment of the present disclosure. Cross-sectional view of a modified example of the outer wall of the header of the heat exchanger according to the first embodiment of the present disclosure.

Hereinafter, the heat exchanger and the method for manufacturing the heat exchanger according to the embodiment of the present disclosure will be described in detail with reference to the drawings. In the figure, the same or equivalent parts are designated by the same reference numerals. In the Cartesian coordinate system XYZ shown in the figure, when the direction in which the heat transfer tube extends is the direction from the front to the back, the horizontal direction is the X axis, the vertical direction is the Z axis, and the direction orthogonal to the X axis and the Z axis. Is the Y axis. Hereinafter, this coordinate system will be referred to and described as appropriate.

(Embodiment 1)
The heat exchanger according to the first embodiment is a heat exchanger in which an embossed portion is formed on the outer wall of the header. In this heat exchanger, a heat transfer tube is brazed to the embossed portion. Hereinafter, the configuration of the heat exchanger will be described with reference to FIGS. 1 to 2, and then the embossed portion will be described with reference to FIGS. 3 to 5. Next, a method of manufacturing the heat exchanger will be described with reference to FIGS. 6-8.

FIG. 1 is a perspective view of the heat exchanger 1A according to the first embodiment. FIG. 2 is a perspective view of the heat transfer tube 20 included in the heat exchanger 1A. In FIG. 1, parts such as a refrigerant pipe and a joint for supplying and discharging the refrigerant are omitted for easy understanding.

As shown in FIG. 1, the heat exchanger 1A has a plurality of headers 10F and 10B in which a refrigerant is supplied from an external device or discharges a refrigerant to the external device, and a plurality of headers 10F and 10B through which the refrigerants of the headers 10F and 10B are circulated to transfer the heat of the refrigerant. The heat transfer tube 20 and a plurality of fins 30 that dissipate the heat of the heat transfer tube 20 are provided.

Headers 10F and 10B have rectangular parallelepiped outer walls 11F and 11B. Although not shown, a flow path for flowing a refrigerant is formed inside the flow path. The headers 10F and 10B are arranged so as to be separated from each other with the longitudinal directions of the outer walls 11F and 11B facing left and right. The headers 10F and 10B are connected to each other by a plurality of heat transfer tubes 20 in order to allow the refrigerant to flow.

Note that the headers 10F and 10B have shapes symmetrical with respect to the XZ plane. Further, the headers 10F and 10B have the same configuration except that they are symmetrical. Therefore, in the present specification, the headers 10F and 10B are simply referred to as headers 10 except when the arrangement relationship is described below. Similarly, the outer wall 11F and 11B are also simply referred to as the outer wall 11 except when the arrangement relationship is explained.

As shown in FIG. 2, the heat transfer tube 20 is formed in a flat front view. Here, the flat shape is a shape in which both ends in the longitudinal direction are rounded into a semicircle in the front view, and is, for example, a flat oval in the front view. The heat transfer tube 20 has an internal space that serves as a flow path for flowing the refrigerant. The internal space extends in the horizontal direction and is partitioned by a plurality of partition walls 21 arranged in the vertical direction in order to enhance heat transfer.

Returning to FIG. 1, the tube axis of the heat transfer tube 20 extends linearly in the direction from the back to the front, that is, in the Y direction. The heat transfer tube 20 and the heat transfer tube 20 are arranged with a gap between them in order to increase the heat exchange rate with air. A plurality of fins 30 are attached to the heat transfer tube 20 in order to dissipate heat transferred from the refrigerant.

The fin 30 is formed in the shape of a rectangular plate in order to improve heat dissipation. Its thickness is 0.09-0.2 mm. Although not shown, a notch that can be fitted to the end portion of the heat transfer tube 20 in the longitudinal direction of the cross section is formed in the longitudinal direction of the fin 30. The number of cutouts is the same as that of the heat transfer tube 20, and the pitch of the cutouts is the same as the left-right pitch of the heat transfer tube 20 and the heat transfer tube 20. Then, the notch portion is fitted to the heat transfer tube 20, and a plurality of fins 30 are attached to the heat transfer tube 20. The fins 30 are fixed to the heat transfer tube 20 by being brazed to the heat transfer tube 20 at these notches. Then, as shown in FIG. 1, the fins 30 are assembled to the plurality of heat transfer tubes 20 in a state where the longitudinal direction is directed to the left-right direction and at a constant pitch, for example, at a pitch of 1.0-2.0 mm. There is.

The fin 30 and the heat transfer tube 20 are made of aluminum or an aluminum alloy in order to enhance the heat transfer property and increase the heat exchange rate between the refrigerant and air. The fin 30 is subjected to surface treatment for anticorrosion, antifouling, hydrophilicity, water repellency, etc. according to the usage environment. A sacrificial anode layer containing zinc is provided on the surface of the heat transfer tube 20 in order to prevent leakage of the refrigerant due to pitting corrosion.

On the other hand, the header 10 is made of aluminum or an aluminum alloy like the heat transfer tube 20. A sacrificial anode layer containing zinc is formed on the surface. Since the header 10 is made of the same material as the heat transfer tube 20, the occurrence of distortion after joining with the heat transfer tube 20 is reduced. The header 10 is formed with an embossed portion 12 for joining the heat transfer tubes 20. Next, the embossed portion 12 of the header 10 will be described with reference to FIGS. 3 to 5.

FIG. 3 is a perspective view of the cut portion when the heat exchanger 1A is cut in the region III shown in FIG. FIG. 4 is a front view of the cut portion. FIG. 5 is a cross-sectional view taken along the line VV shown in FIG. In FIG. 3, the brazing material 14 is omitted for ease of understanding.

As shown in FIGS. 3 and 4, a convex embossed portion 12 is formed on the + Y side on the front side of the outer wall 11, that is, the wall portion on the + Y side.

The embossed portion 12 is a portion formed by a processing method called embossing, half piercing, half punching, dowel processing, or the like. Although the detailed processing method will be described later, as shown in FIG. 5, the embossed portion 12 has a shape in which a part of the outer wall 11 is displaced in the tube axis direction of the heat transfer tube 20. The above-mentioned processing method in which the embossed portion 12 is formed is hereinafter referred to as an embossing processing method.

Specifically, in the embossed portion 12, a part of the outer wall 11 is projected in the Y direction, which is the pipe axis direction, in a local region A narrower than the thickness T of the outer wall 11. The raised portion of the outer wall 11 is parallel to the non-protruded portion of the outer wall 11. The raised distance is half the thickness T of the outer wall 11. Therefore, in the embossed portion 12, the wall surface on the + Y side protrudes by half the thickness T in the + Y direction, and the wall surface on the −Y side is recessed by half the thickness T in the −Y direction. In the present specification, the direction in which the embossed portion 12 is raised is also referred to as a protrusion direction and a displacement direction, and the length in which the embossed portion 12 is raised is also referred to as a protrusion length.

Further, the embossed portion 12 has a shear cross section 120 by the above processing method. Here, the shearing surface 120 is a smooth surface formed by the processing tool when the outer wall 11 is sheared by the above processing method. The shear surface 120 has fine scratches extending in the thickness direction of the wall by the processing tool.

Returning to FIGS. 3 and 4, the embossed portion 12 is formed in a flat shape similar to the heat transfer tube 20 in the front view. Its size is larger than that of the heat transfer tube 20. On the other hand, a through hole 13 into which the heat transfer tube 20 is inserted is formed in the center of the embossed portion 12.

The through hole 13 is formed in a flat shape similar to the heat transfer tube 20 in which the heat transfer tube 20 can be loosely inserted. As shown in FIG. 5, the through hole 13 penetrates the embossed portion 12 in the Y direction. The through hole 13 has a gap C1 over the entire circumference of the heat transfer tube 20.

The gap C1 is formed in a size that allows the molten brazing material 14 to penetrate. Specifically, the gap C1 has a size of, for example, about 0.1-0.5 mm, although it depends on the material and surface treatment of the header 10. Then, the through hole 13 is filled with the brazing material 14, and the heat transfer tube 20 is joined to the inner wall of the through hole 13.

On the other hand, at the + Y end of the through hole 13, a low fillet is formed between the heat transfer tube 20 and the through hole 13 so as to protrude from the through hole 13 and close the heat transfer tube 20. As a result, the joint strength with the heat transfer tube 20 is increased. Although not shown, the brazing material 14 is filled over the entire circumference of the gap C1 between the through hole 13 and the heat transfer tube 20. And the low fillet is formed all around the low fillet. As a result, the gap C1 is closed with high airtightness, and the pressure resistance of the brazed portion is enhanced.

The −Y end of the through hole 13 is continuous with the depression on the + Y side of the embossed portion 12. The above-mentioned shear section 120 is formed on the inner wall of the depression. A gap C2 having a size of about 2-3 times the gap C1 is provided between the sheared cross section 120 and the inserted heat transfer tube 20.

The gap C2 is filled with the brazing material 14 described above. A low fillet is formed in the gap C2, and the gap C2 is closed by the low fillet. Here, although not shown, the gap C2 is filled with the brazing material 14 over the entire circumference and is closed by the wax fillet. As mentioned above, the shear section 120 has fine scratches extending in the thickness direction of the wall. Therefore, the brazing material 14 penetrates between the scratches on the shear surface 120. As a result, the joint strength with the heat transfer tube 20 is increased.
In the present specification, the through hole 13 is also referred to as an insertion hole because the heat transfer tube 20 is inserted into the through hole 13. Further, the through hole 13 is an example of the insertion hole as referred to in the present specification.

Next, a method of manufacturing the heat exchanger 1A will be described with reference to FIGS. 6-8.

FIG. 6 is a cross-sectional view of the outer wall 11 of the header 10 when the embossed portion 12 is formed in the method of manufacturing the heat exchanger 1A according to the first embodiment. FIG. 7 is a cross-sectional view of the outer wall 11 of the header 10 when the through hole 13 is formed in the embossed portion 12 by the same manufacturing method. FIG. 8 is a cross-sectional view of the header 10 when the heat transfer tube 20 is inserted into the through hole 13 by the same manufacturing method. In addition, in FIG. 6-8, the cut surface corresponding to the VI-VIII region shown in FIG. 5 is shown.

First, a plurality of heat transfer tubes 20 having the above-mentioned shapes are manufactured by processing methods such as extrusion molding, pultrusion molding, and bending. Further, a plurality of fins 30 having the above-mentioned shapes are produced by press working. At this time, as the material, aluminum, an aluminum alloy, or a clad material in which these materials are clad is used. The surface is surface-treated according to the purpose of use.

Subsequently, a plurality of heat transfer tubes 20 are arranged at the above-mentioned positions, and the heat transfer tubes 20 arranged in the notches of the plurality of fins 30 are fitted. Further, the notch is brazed to the heat transfer tube 20 to join the heat transfer tube 20 and the fin 30. In this brazing, the brazing material is supplied by applying a paste-like brazing material or placing a fixed brazing material in the vicinity of the notch portion of the fin 30. After that, the brazing material is melted and permeated between the heat transfer tube 20 and the notch of the fin 30. Further, the permeated brazing material is cooled, and the heat transfer tube 20 and the fin 30 are joined with the brazing material. As a result, the heat transfer tube 20 and the fin 30 are joined. In addition, this step is hereinafter referred to as assembling the heat transfer tube 20 and the fin 30.

The header 10 is manufactured in parallel with the production of the heat transfer tube 20 and the fin 30 and the assembly of the heat transfer tube 20 and the fin 30.

In the production of the header, first, the above-mentioned aluminum or aluminum alloy sheet metal having a thickness T is prepared and used as the outer wall 11 of the header 10. Subsequently, the sheet metal is processed by the embossing method described above to form the embossed portion 12 having the shape described above. Specifically, as shown in FIG. 6, the outer wall 11 is arranged between the punch 100 and the die 200, the punch 100 is pushed into the outer wall 11, and the outer wall 11 is sheared by the punch 100. At this time, the pushing amount of the punch 100 is set to half the thickness T of the outer wall 11. As a result, the embossed portion 12 is formed on the outer wall 11. Further, a shear section 120 is formed in a portion of the outer wall 11 pushed by the punch 100. When the punch 100 is pushed in, a large number of fine linear scratches extending in the pushing direction are formed on the sheared surface 120. This step is an example of the embossed portion forming step as referred to in the present specification.

Next, as shown in FIG. 7, a through hole 13 having the above-mentioned shape is formed in the outer wall 11 on which the embossed portion 12 is formed. In the formation of the through hole 13, the through hole 13 is formed in the outer wall 11 by using a cutting tool, a machine tool, a press machine, or the like. In other words, the through hole 13 is formed by machining or press working. This step is an example of the through hole forming step as referred to in the present specification.

Subsequently, the rectangular parallelepiped header 10 described above is formed by pressing the outer wall 11 on which the through hole 13 is formed. In the through hole forming step, the through hole 13 may be formed and the header 10 having the above-mentioned shape may be formed by press working.

Next, as shown in FIG. 8, the heat transfer tube 20 is inserted into the through hole 13 of the header 10 formed in a rectangular parallelepiped shape by press working. At this time, a gap C1 is provided between the inner wall of the through hole 13 and the heat transfer tube 20. Here, although not shown, the heat transfer tube 20 to be inserted is a heat transfer tube 20 to which the fins 30 are joined by assembling the heat transfer tube 20 and the fins 30. This step is an example of the heat transfer tube insertion step as referred to in the present specification.

Next, the brazing material 14 is placed in the opening of the through hole 13 with the gap C1 provided. Then, the brazing material 14 is heated and melted, and as shown by an arrow R, the brazing material 14 is infiltrated into the gap C1 between the inner wall of the through hole 13 and the heat transfer tube 20. Further, the brazing material 14 is infiltrated into the gap between the inner wall of the through hole 13 and the sheared surface 120. As a result, as shown in FIG. 5, the brazing material 14 protrudes from the recess of the embossed portion 12 having the opening of the through hole 13 and the sheared cross section 120, and a low fillet is formed to close these gaps by surface tension. Further, the brazing material 14 penetrates between the fine linear scratches on the shear surface 120. Then, the brazing material 14 is cooled and cured. The brazing material 14 forms a low fillet, and the heat transfer tube 20 is firmly joined to the header 10. This step is an example of the brazing step as referred to in the present specification.

In the brazing step, the brazing material 14 is placed in the opening of the through hole 13, and the brazing material 14 may be in a well-known form such as a paste, a wire, or a foil.

By the above steps, the fin 30, the heat transfer tube 20, and the header 10 are assembled, and the heat exchanger 1A is completed.

As described above, in the heat exchanger 1A according to the first embodiment, the heat transfer tube 20 is joined by the brazing material 14 to the sheared cross section 120 of the embossed portion 12 formed in the header 10 and the inner wall of the through hole 13. .. Therefore, the joint area between the heat transfer tube 20 and the header 10 is large, and the joint strength is high.

The embossed portion 12 is formed in a shape in which a part of the wall portion of the outer wall 11 of the header 10 is projected in the tube axial direction of the heat transfer tube 20. Therefore, the embossed portion 12 is recessed in the direction opposite to the raised direction. Then, the brazing material 14 is filled in the depression. As a result, the embossed portion 12 supports the heat transfer tube 20. As a result, in the heat exchanger 1A, the strength of the heat transfer tube 20 is high.

Generally, when the through hole 13 and the peripheral wall are formed by burring, it is difficult to form the through hole 13 and the peripheral wall when the thickness of the outer wall 11 is larger than the inner diameter of the through hole 13.

On the other hand, the embossed portion 12 is formed by a punch 100 pushing a part of the outer wall 11 by a processing method called embossing, half piercing, or the like. Therefore, in the heat exchanger 1A, the embossed portion 12 can be easily manufactured even when the thickness of the outer wall 11 is larger than the inner diameter of the through hole 13. As a result, it is easy to increase the thickness of the outer wall 11 to increase the joint strength between the heat transfer tube 20 and the header 10.

Further, since the embossed portion 12 which is one size larger than the through hole 13 is only formed on the outer wall 11, it is easy to manufacture even if the thickness of the outer wall 11 is increased as compared with the burring process.

In the heat exchanger 1A, a through hole 13 is formed in the embossed portion 12 by machining or press working. Therefore, the embossed portion 12 and the through hole 13 can be formed with high position accuracy as compared with the case where the through hole 13 and the peripheral wall are formed by the burring process.

(Embodiment 2)
In the first embodiment, one through hole 13 is formed in one embossed portion 12. As a result, one heat transfer tube 20 is joined to one embossed portion 12. However, the embossed portion 12 is not limited to this. In the heat exchanger 1B according to the second embodiment, a plurality of through holes 43 are formed in one embossed portion 42. A plurality of heat transfer tubes 20 are joined to the plurality of through holes 43.

Hereinafter, the heat exchanger 1B according to the second embodiment will be described with reference to FIGS. 9 to 12. In the second embodiment, a configuration different from that of the first embodiment will be described.

FIG. 9 is a perspective view of the heat exchanger 1B according to the second embodiment. FIG. 10 is a front view of the heat exchanger 1B. FIG. 11 is a cross-sectional view taken along the XI-XI cutting line shown in FIG. FIG. 12 is a cross-sectional view of the header 40 when the heat transfer tube 20 is inserted into the through hole 43 in the method of manufacturing the heat exchanger 1B according to the second embodiment. Note that FIG. 9 shows a cut portion when the header 40 is partially cut in a plane parallel to the YZ plane, as in FIG. Further, in FIG. 12, the cut surface of the XI-XI cutting line shown in FIG. 10 is shown.

As shown in FIG. 9, the heat exchanger 1B includes a header 40 in which an embossed portion 42 in which two heat transfer tubes 20 are joined is formed.

As shown in FIG. 10, the embossed portion 42 is formed in a rectangular shape when viewed from the front. The longitudinal direction of the embossed portion 42 is directed in the vertical direction. Its length is larger than the longitudinal direction of the cross section of the heat transfer tube 20. Further, the lateral direction of the embossed portion 42 is directed to the left-right direction. The length in the lateral direction is larger than the sum of the pitch P of the heat transfer tube 20 and the length of the heat transfer tube 20 in the lateral direction. As a result, the embossed portion 42 has a size that allows two through holes 43 having the same shape and the same size as the through holes 13 described in the first embodiment to be arranged. The embossed portion 42 is formed with the two through holes 43 described above. A heat transfer tube 20 is inserted into each of the through holes 43.

As shown in FIG. 11, a gap C1 similar to that of the first embodiment is provided between the inner wall of the through hole 43 and the heat transfer tube 20. Then, the brazing material 14 is filled between the inner wall of the through hole 43 and the heat transfer tube 20 as in the first embodiment. As a result, the heat transfer tube 20 is joined to the inner wall of the through hole 43. As a result, in the heat exchanger 1B, two heat transfer tubes 20 are joined to the embossed portion 42.

On the other hand, the same gap C2 as in the first embodiment is provided between the inner wall UW at the upper end of the recess of the embossed portion 42 and the heat transfer tube 20. As a result, the brazing material 14 is filled as in the first embodiment. The inner wall UW has the same shear section 120 as in the first embodiment. As a result, the heat transfer tube 20 is firmly joined to the inner wall UW.

On the other hand, in the inner wall LW at the lower end of the recess of the embossed portion 42, a gap C3 larger than the gap C2 is formed between the embossed portion 42 and the heat transfer tube 20. As a result, the brazing material 14 is not filled in the gap C3, and the brazing material 14 exists only in the vicinity of the inner wall LW. As a result, the inner wall LW is not joined to the heat transfer tube 20.

As described above, in the embossed portion 42, only a part of the inner wall of the recess is joined to the heat transfer tube 20 by the brazing material 14. However, a part of the inner wall has a shear surface of 120. Therefore, the header 40 and the heat transfer tube 20 are more firmly joined to each other as compared with the case where the embossed portion 42 is not formed.

Next, the method of manufacturing the heat exchanger 1B according to the second embodiment will be described.

First, the heat transfer tube 20 and the fin 30 are manufactured in the same manner as in the first embodiment, and then the heat transfer tube 20 and the fin 30 are assembled. Further, the header 40 having the above-mentioned shape is produced. At this time, the embossed portion 42 and the through hole 43 having the above-mentioned shapes are produced by performing the same embossed portion forming step and through hole forming step as in the first embodiment.

Subsequently, as shown in FIG. 12, the heat transfer tube 20 is inserted with the gap C1 provided in the through hole 43. Then, the brazing material 14 having a shape surrounding the outer periphery of the heat transfer tube 20 is installed in the heat transfer tube 20 while maintaining the gap C1. Then, as in the first embodiment, the brazing material 14 is heated and melted, and the brazing material 14 is infiltrated into the gap C1 between the inner wall of the through hole 43 and the heat transfer tube 20. At this time, the brazing material 14 penetrates into the gap C1 and the gap C2 between the inner wall UW at the upper end of the recess of the embossed portion 42 and the heat transfer tube 20 by surface tension. Then, the brazing material 14 is filled in the gap C2.

On the other hand, at the lower end of the recess of the embossed portion 42, the brazing material 14 that has penetrated into the gap C1 hangs down due to gravity as shown by the arrow S. The gap C3 is larger than the gap C2 of the inner wall UW at the upper end of the recess of the embossed portion 42. Therefore, the brazing material 14 is unlikely to be filled in the gap C3 due to surface tension.

Here, when the brazing material 14 is melted in an amount more than necessary for joining the inner wall of the through hole 43 and the heat transfer tube 20, wax clogging occurs or the header 40 or the heat transfer tube 20 is melted, so-called. Erosion may occur. However, in the second embodiment, a gap C3 larger than the gap C2 is provided at the lower end of the recess of the embossed portion 42. Therefore, the surplus brazing material 14 flows downward due to gravity and gathers in the gap C3. As a result, wax clogging is less likely to occur, and so-called erosion is less likely to occur.

After the brazing material 14 is heated and melted, the brazing material 14 is cooled and cured. As a result, the heat transfer tube 20 is brazed to the header 10. The heat exchanger 1B is completed by the above steps.

As described above, also in the heat exchanger 1B according to the second embodiment, the heat transfer tube 20 is brazed to the inner wall UW of the embossed portion 42 having the sheared cross section 120 as in the first embodiment. Therefore, even in the heat exchanger 1B, the joint strength between the heat transfer tube 20 and the header 40 is high.

In the burring process, if the pitch P of the heat transfer tube 20 is too small, the pitch of the through holes 43 also becomes small, and the strength of the wall portion between the through holes 43 decreases. As a result, it may be difficult to form the through hole 43 and the peripheral wall.

However, in the heat exchanger 1B, the embossed portion 42 to which a plurality of heat transfer tubes 20 can be joined is formed in the same embossed portion forming step as in the first embodiment. Further, a through hole 43 is formed in the embossed portion 42 by the same through hole forming step as in the first embodiment. That is, the through hole 43 is formed by machining or press working. Therefore, the embossed portion 42 and the through hole 43 can be formed more easily than the burring process.

(Embodiment 3)
In the first and second embodiments, a step is provided between the outer wall 11 and the embossed portions 12 and 42. That is, the embossed portions 12 and 42 have a step shape protruding from the outer wall 11 to the front side, and as a result, a step is provided. The number of stages is one. However, the embossed portions 12 and 42 are not limited to this. The embossed portions 12 and 42 may have a stepped shape having a plurality of steps. The heat exchanger 1C according to the third embodiment includes a stepped embossed portion 52.

Hereinafter, the heat exchanger 1C according to the third embodiment will be described with reference to FIGS. 13 to 15. In the third embodiment, a configuration different from the first and second embodiments will be described.

FIG. 13 is a perspective view of the heat exchanger 1C according to the third embodiment of the present disclosure. FIG. 14 is a front view of the heat exchanger 1C. FIG. 15 is a cross-sectional view taken along the XV-XV cutting line shown in FIG. Note that FIG. 13 shows a cut portion when the header 50 is partially cut in a plane parallel to the YZ plane, as in FIG. Further, in FIG. 13, the brazing material 14 is omitted for easy understanding.

As shown in FIGS. 13 and 14, the heat exchanger 1C includes a header 50, and an embossed portion 52 projecting to the front side in a stepped manner is formed on the outer wall 51 of the header 50.

The embossed portion 52 is formed in the shape of a staircase having a plurality of steps. Specifically, the embossed portion 52 is formed in the shape of a staircase having three steps 521-523 that rise toward the front side from the peripheral edge toward the center. Each step 521-523 of the embossed portion 52 has a flat front view similar to the cross-sectional shape of the heat transfer tube 20. Each stage is similar to each other. The step 523 on the center side of the embossed portion 52 is the smallest of the steps 521-523, but the step 523 is larger than the cross-sectional shape of the heat transfer tube 20 in front view because it is connected to the heat transfer tube 20.

These stages 521-523 are projected on the front side, that is, in the + Y direction by being formed by the embossing method described in the first embodiment.

Specifically, as shown in FIG. 15, the step 521 is formed by a part of the outer wall 51 protruding in the + Y direction by the protrusion length L1 by the embossing method. The protruding length L1 is more than half the thickness T of the outer wall 51. As a result, the −Y side of the step 521 is recessed by the protrusion length L1 from the −Y surface of the outer wall 51. As a result, there is a step having a protruding length L1 between the −Y surface of the step 521 and the −Y surface of the outer wall 51. The stepped surface has a shear section 121 formed by an embossing method.

Further, the step 522 is formed by a part of the step 521 protruding in the + Y direction by the embossing method. The protruding length L2 is the same as the protruding length L1 of the step 521. Further, the + X end and the −X end of the step 522 are located on the center side of the step 521 by a width W from the + X end and the −X end of the step 521. Here, the width W is more than half of the thickness T of the outer wall 51. As a result, the step 522 is smaller than the step 521 in the XY cross-sectional view.

The -Y side of the step 522 is formed by the embossing method, so that the protrusion length L2 is recessed from the -Y surface of the step 521. As a result, the −Y surface of the step 522 has a step with a protruding length L2 from the −Y surface of the step 521. Further, the stepped surface is formed by a shearing surface 122.

Further, the step 523 is formed by a part of the step 522 protruding in the + Y direction by the embossing method. The protruding length L3 is the same as the protruding length L1 of the step 521, and the positional relationship of the step 523 with respect to the step 522 is the same as the positional relationship of the step 522 with respect to the step 521. The step 523 has the same step as the protrusion length L3 on the −Y side, and has a shearing cross section 123 on the step surface.

The step 523 is formed inside the step 522. Further, the step 522 is formed inside the step 521. As a result, the −Y side of the step 523 is the most recessed among the steps 521-523. A through hole 53 is formed in the central portion thereof so as to penetrate the central portion in the Y direction. A heat transfer tube 20 extending in the same direction is inserted into the through hole 53.

The heat transfer tube 20 has a gap C1 between it and the inner wall of the through hole 53, as in the first embodiment. Further, the heat transfer tube 20 has a gap C2 between the heat transfer tube 20 and the shearing section 123 on the −Y side of the step 523, similarly to the shearing section 120 described in the first embodiment. Further, the heat transfer tube 20 has gaps C4 and C5 between the shear sections 122 and 121.

The brazing material 14 is filled in these gaps C1, C2, C4, and C5. A low fillet is formed in the gap C5. Although not shown, this low fillet is formed over the entire circumference of the gap C5 between the heat transfer tube 20 and the shear section 121. As a result, the gap C5 is closed with high airtightness, and the brazing pressure resistance is high. As a result, the gaps C1, C2, and C4 are also closed with high airtightness.

Further, since the brazing material 14 has penetrated into the shear section 121-123, the joint strength between the heat transfer tube 20 and the embossed portion 52 is high.

Next, the manufacturing method of the heat exchanger 1C according to the third embodiment will be described.

First, the heat transfer tube 20 and the fin 30 are manufactured in the same manner as in the first and second embodiments, and then the prepared heat transfer tube 20 and the fin 30 are assembled.

Further, the header 50 having the embossed portion 52 described above is manufactured. In the production of the header 50, the stepped steps 521-523 are formed on the outer wall 51 by repeating the embossed portion forming step described in the first embodiment.

Specifically, the punch 100 and the die 200 described in the first embodiment are used to form the step 521, and then the punch 100 and the die 200 are used with another punch and die (not shown) to form the step 521. A step 522 is formed inside. Further, the other punch and die are replaced with another one to form a step 523 inside the step 522. As a result, a stepped embossed portion 52 is formed on the outer wall 51.

Next, the same through hole forming step and brazing step as in the first embodiment are performed. As a result, a through hole 53 is formed in the embossed portion 52, and the heat transfer tube 20 is inserted into the formed through hole 53. Further, the gaps C1, C2, C4, and C5 formed between the heat transfer tube 20 and the through hole 53 or the embossed portion 52 are filled with the brazing material 14.

In the filling of the brazing material 14, the molten brazing material 14 permeates the gaps C1, C2, C4, and C5 due to the capillary phenomenon. As a result of the molten brazing material 14 gathering in a narrow space due to surface tension, it gathers in the gaps C1, C2, C4, and C5, so that it is difficult for the molten brazing material 14 to flow from the end of the heat transfer tube 20 into the inside thereof. As a result, so-called wax clogging, in which the internal space of the heat transfer tube 20 is blocked by the brazing material 14, is suppressed. The brazing material 14 fills the gaps C1, C2, C4, and C5 to close the gaps C1, C2, C4, and C5 with high airtightness.

In the third embodiment, the embossed portion 52 formed in the shape of a staircase and having three steps, that is, the steps 521-523 is described. However, the embossed portion 52 may have a plurality of stages. Therefore, the embossed portion 52 may have, for example, two steps. Further, the embossed portion 52 may have more than three steps.

Further, in the third embodiment, the low fillet is formed in the gap C5, but the low fillet may be formed in the gaps C2 and C4 in addition to the gap C5. This is because even in such a form, the heat transfer tube 20 can be brazed to at least the sheared surface 121. The brazing fillet may be formed in the gaps C2, C4, and C5 according to the amount of the brazing material 14 supplied in the brazing step.

In the third embodiment, one heat transfer tube 20 is joined to the embossed portion 52, but as in the second embodiment, a plurality of heat transfer tubes 20 may be joined to the embossed portion 52.

As described above, the heat exchanger 1C according to the third embodiment includes an embossed portion 52 formed in a stepped shape, and the embossed portion 52 has a shear section 121-123. In the heat exchanger 1C as well, as in the first and second embodiments, the heat transfer tube 20 is brazed to the shear section 121-123, so that the joint strength between the heat transfer tube 20 and the header 50 is high.

Further, in the heat exchanger 1C, since the low fillet is larger than that in the first embodiment, the joint strength of the heat transfer tube 20 is higher than that in the first embodiment.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. For example, in the first embodiment, the embossed portions 12, 42, 52 project toward the outside of the headers 10, 40, 50. However, the embossed portions 12, 42 and 52 are not limited to this. The embossed portions 12, 42, and 52 may project in the axial direction of the heat transfer tube 20. Therefore, the embossed portions 12, 42, 52 may protrude inward of the headers 10, 40, 50.

FIG. 16 is a cross-sectional view of a modified example of the heat exchanger 1A according to the first embodiment. Note that FIG. 16 shows a cross-sectional view taken along the cutting line at the same location as the VV cutting line shown in FIG.

As shown in FIG. 16, the heat exchanger 1D includes a header 60 in which an embossed portion 62 projecting toward the internal space, which is a flow path, is formed. The embossed portion 62 projects in the tube axis direction of the heat transfer tube 20, more specifically, in the −Y direction.

In this way, the embossed portions 12, 42, 52 may protrude toward the inside of the headers 10, 40, 50. Even in such a form, the recesses of the embossed portions 12, 42 and 52 can be filled with the brazing material 14 to firmly join the heat transfer tube 20 to the embossed portions 12, 42 and 52.

In the first embodiment, the embossed portions 12, 42, 52, 62 are projected by half the thickness T of the outer wall 11. Further, the thicknesses of the embossed portions 12, 42, 52 and 62 are the same as the thickness T of the outer wall 11. However, the embossed portions 12, 42, 52 and 62 are not limited to this. The embossed portions 12, 42, 52, 62 may project in the pipe axis direction, and the projecting length thereof is arbitrary. Further, the thicknesses of the embossed portions 12, 42, 52 and 62 are also arbitrary. For example, the embossed portions 12, 42, 52, 62 may protrude by 1/3 of the thickness T of the outer wall 11, and the thickness of the embossed portions 12, 42, 52, 62 presses the punch 100. By doing so, it may be thinner than the thickness T.

In the first embodiment, the headers 10, 40, 50, and 60 have a rectangular parallelepiped outer wall 11, but the headers 10, 40, 50, and 60 are not limited to this. The headers 10, 40, 50, 60 may have outer walls 11, 41, 51, 61 in which the through holes 13, 43, 53 and the embossed portions 12, 42, 52, 62 are formed. Therefore, the headers 10, 40, 50, and 60 have an arbitrary shape to this extent. For example, the headers 10, 40, 50, 60 may have a cylindrical outer wall 11.

Further, as far as the above is concerned, the materials of the headers 10, 40, 50 and 60 are also arbitrary. In the first embodiment, the sacrificial anode layer is formed on the surface of the headers 10, 40, 50, 60, but the headers 10, 40, 50, 60 are not limited to this. For example, the headers 10, 40, 50, 60 may be formed of a brazing sheet of the outer wall 71.

FIG. 17 is a cross-sectional view of a modified example of the outer wall 11 of the header 10. Note that FIG. 17 shows only a part of the outer wall 11.

The outer wall 71 is formed of a brazing sheet in which a brazing material is provided as a skin material on aluminum or an aluminum alloy as a core material. Specifically, as shown in FIG. 17, the outer wall 71 is formed of a first layer 72 formed of an alloy containing manganese and aluminum, and an aluminum alloy having a lower melting point than the alloy of the first layer 72. A second layer 73 and a third layer 74 formed of the same aluminum alloy as the second layer 73 or an alloy containing zinc and aluminum are laminated. Here, the aluminum alloy of the second layer 73 is the same material as the brazing material 14.

As described above, the headers 10, 40, 50, and 60 may be formed of the brazing sheet of the outer wall 71. In this case, the skin material of the brazing sheet may be formed on one side of the core material or on both sides of the core material, as in the outer wall 71. The shearing surface 120 described above may be formed on a brazing material which is a skin material. In such a form, since the shear surface 120 itself is a brazing material, the heat transfer tube 20 can be reliably joined.

The internal structure of the headers 10, 40, 50, and 60 is also arbitrary. The inside of the headers 10, 40, 50, and 60 may be divided by a partition wall, and there may be a plurality of flow paths. In the heat exchanger 1A-1D, the number of headers 10, 40, 50, and 60 may be one depending on the flow path.

In the first embodiment, the headers 10, 40, 50, 60 and 70 are formed of one member, but the headers 10, 40, 50, 60 and 70 are manufactured by combining a plurality of header parts. It may have been done. In that case, a plurality of header parts may be brazed.

As described above, the headers 10, 40, 50, 60, 70 have through holes 13, 43, 53 and outer walls 11, 41, 51, 61 in which the embossed portions 12, 42, 52, 62 are formed. You just have to do it. Then, the heat transfer tube 20 may be brazed to the inner walls of the embossed portions 12, 42, 52, 62 and the through holes 13, 43, 53. Therefore, as long as this condition is satisfied, the direction in which the outer walls 11, 41, 51, and 61 are oriented and the direction in which the heat transfer tube 20 extends are arbitrary. Further, as long as this condition is satisfied, the number of heat transfer tubes 20 provided is also arbitrary.

For example, headers 10, 40, 50, 60, 70 include outer walls 11, 41, 51, 61 facing forward or backward, and outer walls 11, 41, 51, 61 facing right or left, front or rear. A large number, for example, 10 to 100 heat transfer tubes 20 may be connected to the facing outer walls 11, 41, 51, 61, and the heat transfer tubes 20 may be arranged in the left-right direction. Further, a large number, for example, 2 to 100 heat transfer tubes 20 may be connected to the outer walls 11, 41, 51, 61 facing upward or downward, and the heat transfer tubes 20 may be arranged in the vertical direction.

Further, as long as the above conditions are satisfied, the number of heat transfer tubes 20 brazed to the embossed portions 12, 42, 52, and 62 is, of course, arbitrary. For example, a plurality of heat transfer tubes 20 may be brazed to the embossed portions 12, 42, 52, and 62. Further, when the headers 10, 40, 50, 60, and 70 are provided with a plurality of outer wall walls 11, 41, 51, 61 facing in different directions, the embossed portions are formed on the outer wall walls 11, 41, 51, 61 facing in which direction. It is also optional that 12, 42, 52, 62 are provided. For example, the embossed portions 12, 42, 52, 62 may be provided on the outer walls 11, 41, 51, 61 facing upward or downward.

The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Moreover, the above-described embodiment is for explaining the present disclosure, and does not limit the scope of the present disclosure. That is, the scope of the present disclosure is indicated by the claims, not the embodiments. And various modifications made within the scope of the claims and within the equivalent meaning of disclosure are considered to be within the scope of the present disclosure.

This application is based on Japanese Patent Application No. 2019-47920 filed on March 15, 2019. The specification, claims, and drawings of Japanese Patent Application No. 2019-47920 shall be incorporated into this specification as a reference.

1A-1D heat exchanger, 10,10F, 10B header, 11,11F, 11B outer wall, 12 embossed part, 13 through hole, 14 brazing material, 20 heat transfer tube, 21 partition wall, 30 fins, 40 header, 41 outer wall , 42 embossed part, 43 through hole, 50 header, 51 outer partition wall, 52 embossed part, 53 through hole, 60 header, 61 outer wall, 62 embossed part, 71 outer wall, 72 first layer, 73 second layer , 74 Third layer, 100 punch, 120, 121, 122, 123 shear cross section, 200 die, 521-523 steps, A area, C1-C5 gap, L1-L3 protrusion length, P pitch, LW, UW inner wall, R, S arrow, T thickness, W width.

Claims (11)

1. A heat transfer tube that transfers heat to the fins,
   The heat transfer tube has an insertion hole into which the heat transfer tube is inserted and an outer wall surrounding the insertion hole and having an embossed portion protruding in the tube axis direction of the heat transfer tube. The heat transfer tube has the embossed portion and the insertion hole. With the header waxed on the inner wall of
   A heat exchanger equipped with.
2. The embossed portion has a dent on the side opposite to the protruding direction.
   The heat transfer tube is brazed to the inner wall of the recess by a brazing material filled between the heat transfer tube and the recess of the embossed portion.
   The heat exchanger according to claim 1.
3. The heat transfer tube is brazed over the entire inner wall of the depression or a part of the inner wall of the depression.
   The heat exchanger according to claim 2.
4. A plurality of the insertion holes are formed in the outer wall.
   The heat exchanger according to any one of claims 1 to 3.
5. The embossed portion has the shape of a staircase having a plurality of steps.
   The heat exchanger according to any one of claims 1 to 4.
6. The heat transfer tube is brazed to the inner wall of the embossed portion by a brazing material filled between the heat transfer tube and the inner wall of at least one of the plurality of stages.
   The heat exchanger according to claim 5.
7. An embossed portion forming step of embossing the outer wall of the header to form an embossed portion on the outer wall.
   A through hole forming step of forming a through hole in the embossed portion,
   A heat transfer tube insertion step of inserting a heat transfer tube into the through hole, and
   A brazing step of brazing the heat transfer tube inserted into the through hole to the embossed portion and the inner wall of the through hole.
   A method of manufacturing a heat exchanger comprising.
8. In the brazing step, a brazing material is filled between the inner wall of the recess on the side opposite to the protruding direction of the embossed portion and the heat transfer tube, and the heat transfer tube is brazed to the embossed portion with the brazing material. ,
   The method for manufacturing a heat exchanger according to claim 7.
9. In the embossing portion forming step, a sheared cross section is formed on the outer wall by embossing the outer wall.
   The method for manufacturing a heat exchanger according to claim 8.
10. In the brazing step, a brazing material is filled between the sheared surface and the heat transfer tube, and the heat transfer tube is brazed to the sheared surface with the brazed material.
    The method for manufacturing a heat exchanger according to claim 9.
11. In the through hole forming step, the through hole is formed by pressing or machining the embossed portion.
    The method for manufacturing a heat exchanger according to any one of claims 7 to 10.

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